Chilled Beam Application Guidebook

Maija Virta (ed.) David Butler Jonas Gräslund Jaap Hogeling Erik Lund Kristiansen Mika Reinikainen Gunnar Svensson rehva Federation of European Heating and Air-conditioning Associations

GUIDEBOOK NO 5

Maija Virta (ed.) David Butler Jonas Gräslund Jaap Hogeling Erik Lund Kristiansen Mika Reinikainen Gunnar Svensson

DISCLAIMER

This Guidebook is the result of the efforts of REHVA volunteers. It has been written with care, using the best available information and the soundest judgment possible. REHVA and the REHVA volunteers, who contributed to this Guidebook, make no rep- resentation or warranty, express or implied, concerning the completeness, accuracy, or applicability of the information contained in the Guidebook. No liability of any kind shall be assumed by REHVA or the authors of this Guidebook as a result of reliance on any information contained in this document. The user shall assume the entire risk of the use of any and all information in this Guidebook.

------

All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronically or mechanical, including photocopy recording, or any information storage and retrieval system, without permission in writing from the publisher.

Requests for permission to make copies of any part of the work should be addressed to REHVA, P.O. Box 82, 1200 Brussels e–mail: [email protected]

ISBN 2-9600468-3-8

Printed in Finland, Forssan Kirjapaino Oy, Forssa

List of contents

Terminology, Symbols and Units ...... vii 1. CHILLED BEAM COOLING AND HEATING IN A NUTSHELL...... 1 2. THEORETICAL BACKGROUND ...... 3 2.1 Heat Transfer...... 3 2.1.1 Radiation ...... 3 2.1.2 Convection ...... 3 2.1.3 Evaporation ...... 3 2.2 Heat Transfer Efficiency in Chilled Beams ...... 4 2.3 Room Control...... 5 3. ROOM AIR CONDITIONING SYSTEM SELECTION ...... 6 3.1 Overview of Different Room Units ...... 6 3.2 Conditions for Chilled Beam Applications ...... 7 3.3 Life Cycle Cost (LCC) ...... 7 4. CREATING GOOD INDOOR CLIMATE WITH CHILLED BEAMS...... 10 4.1 Types of Chilled Beam Systems ...... 10 4.1.1 Passive Chilled Beams...... 10 4.1.2 Active Chilled Beams...... 11 4.1.3 Perimeter Passive Chilled Beams...... 11 4.1.4 Integrated Service Beams ...... 12 4.2 Comfortable Indoor Climate with Chilled Beams...... 12 4.3 Room Construction Design Requirements...... 15 4.4 Positioning of chilled beams...... 17 4.4.1 Positioning of passive chilled beams ...... 17 4.4.2 Positioning of perimeter chilled beams ...... 17 4.4.3 Positioning of active chilled beam...... 18 4.5 Demonstration of Indoor Climate Conditions...... 19 5. CHILLED BEAM SYSTEM DESIGN ...... 21 5.1 Cooling with Active Chilled Beams ...... 21 5.2 Heating with Active Chilled Beams...... 24 5.3 Active Chilled Beams in Hot and Humid Climates...... 25 5.4 Prevention of Condensation...... 26 5.5 Air and Water Distribution Systems ...... 27 5.5.1 Distribution Pipe Work ...... 28 5.5.2 Chiller Plant and Buffer Vessel ...... 29 5.5.3 Ductwork and Air Handling Unit...... 30 5.6 Use of Free Cooling and Sustainable Heat Sources ...... 31 5.7 Room Controls ...... 31 5.8 Design Methodology for Chilled Beam System...... 32

iii

6. PRODUCT SELECTION...... 34 7. INSTALLATION AND COMMISSIONING...... 37 7.1 Installation...... 37 7.2 Flushing...... 38 7.3 Filling-up and venting the system...... 38 7.4 Commissioning...... 38 8. RUNNING OF CHILLED BEAM SYSTEM ...... 41 8.1 Maintenance and Replacement ...... 41 8.2 Essential Issues in Beam Operation...... 41 9. CASE STUDIES ...... 43 9.1 A Case of Office Building in United Kingdom...... 43 9.2 A case of Office Building in France ...... 44 9.3 A case of Office Building in Sweden...... 45 9.4 A Case of Office Building in Belgium with High Performance Values ...... 46 9.5 A Case of Office Building in Finland with Passive Chilled Beams ...... 47 10. REFERENCES ...... 48

Foreword

REHVA is a 40-year-old organisation of mate, control of exposure to environ- European professionals in the field of mental tobacco smoke with ventilation, building services (heating, ventilating and criteria of clean ventilation systems, low air-conditioning). REHVA represents temperature heating systems, indoor envi- more than 100,000 experts from 30 Euro- ronment and productivity. pean countries. The topic of the guidebook on chilled REHVA´s main activity is to develop and beam cooling is extremely important with disseminate economical, energy efficient respect to indoor environment. This rela- and healthy technology for the mechanical tively new technology has rapidly spread services of buildings. The work is super- all over the Europe. Its advantages are in vised by the board of directors. Each low noise generation, low room velocities member of the board is responsible for and flexibility. High temperature level of work in a specific area of REHVA activi- cooling media also improves the energy ties. efficiency of the mechanical cooling and allows longer periods of free cooling. The REHVA Guidebook projects are coordi- Guidebook presents the principles of nated by the Technical Committee of chilled beam cooling and illustrates its REHVA. The objectives of this work are: practical applications.

Initiate work for technical guidebooks The guidebook on chilled beam cooling is in the area of building services written by a working group of highly Establish task forces for such qualified international experts under the guidebooks leadership of Mrs Maija Virta from Develop distribution of REHVA Finland. The work is done on a voluntary Guidebooks to members and other basis with no commercial interest. The professionals document is approved by the REHVA Supervise the quality of REHVA board. The board would like to express its Guidebooks sincere gratitude to the working group for their invaluable work. Several task forces are currently working towards REHVA Guidebooks such as: Olli Seppänen commissioning of HVAC systems for President Elect of REHVA and Chairman good energy efficiency and indoor cli- of the technical committee

Member countries of REHVA

Belgium Greece Romania Bosnia and Herzegovina Hungary Russia Bulgaria Ireland Serbia and Montenegro Croatia Italy Slovakia Czech Republic Latvia Slovenia Denmark Lithuania Spain Estonia The Netherlands Sweden Finland Norway Switzerland France Poland Turkey Germany Portugal United Kingdom

Work Group

This guidebook has been developed in a work-group consisting of the following experts: David Butler, Principal Consultant, BRE, Watford, United Kingdom Jonas Gräslund, Technical Director, Skanska Fastigheter Stockholm AB, Sweden Jaap Hogeling, Director, ISSO, Rotterdam, the Netherlands Erik Lund Kristiansen, Marketing Engineer, Danfoss A/S, Denmark Mika Reinikainen, Director, Olof Granlund Oy, Helsinki, Finland Gunnar Svensson, Export Director, Swegon AB, Stockholm, Sweden Maija Virta, M.Sc., Development Director, Halton Oy, Kausala, Finland

Reviewers

The following persons have reviewed the book and made valuable suggestions for improvements: Francis Allard, France Derrick Braham, CIBSE – Chartered Institution of Building Services Engineers, United Kingdom Peter Novak, Energotech d.o.o. Slovenia Michael Schmidt, Germany Olli Seppänen, Professor, Helsinki University of Technology, Finland Bjarne W. Olesen, DTU, Denmark

Acknowledgements

The workgroup wishes to thank the contribution of Mrs. Verity Braham for checking the grammar and spelling and Mr. Harri Itkonen for his help with finalising this book.

Terminology, Symbols and Units

Terms and definitions

The terms and definitions are based on the CEN standard of Chilled Beams, testing and rating of active chilled beams. [12, 13] Additional definitions are mainly from an ISSO publication of Climatic Ceilings and Chilled Beams; Applications of Low Temperature Heating and High Temperature Cooling [1].

Active (Ventilated) Chilled Beam Draught Rating (DR-value) A convector with integrated air supply The percentage of people predicted to be where primary air, induced air or primary dissatisfied due to draught. air plus induced air passing through the cooling coil(s). The cooling medium in the Effective Length coil is water. The beam is normally The length of the cooling section of a mounted under the ceiling. chilled beam.

Chilled Beam Induced Airflow A cooled element or cooling coil situated in, The secondary airflow from the room induced above or under a ceiling which cools con- into the chilled beam by the primary air. vectively using natural or induced air flows. The cooling medium is usually water. Induction Rate The total volume of air displaced by in- Chilled Ceiling (Radiant Ceiling) duction, divided by the volume of primary Ceiling panels that are made up of elements air supplied. that connect together and cool primarily through radiation. The cooling medium is Infiltration usually water. The transport of air through leakage paths in the envelope of a building, resulting Closed Chilled Beam from pressure (e.g. wind) and temperature An active chilled beam where there is an differences. integrated secondary air path directly from the room space. Closed chilled beams are Mixed Airflow Rate mainly situated within a suspended ceil- The total airflow rate supplied from the ing. The cooling medium is usually water. beam to the space (mixture of primary air and induced air) Dew Point The temperature at which the water vapour Mean Radiant Temperature present in the air condenses. The theoretical uniform temperature of a room in which the radiant exchange be- Draught tween the human body and its environ- Unwanted local cooling of the body ment is the same as the radiant exchange caused by air movement. in the actual location.

vii

Nominal Cooling Capacity Passive Chilled Beam (Static Beam) The cooling capacity calculated from the The cooled element or cooling coil fixed curve of best fit for the nominal cooling in, above or under a ceiling fitted with a water flow rate at the nominal temperature cooling coil that cools mainly convectively difference. using natural airflows. The cooling medium is usually water. Nominal Cooling Water Flow Rate The flow rate that gives a cooling water Primary Airflow Rate temperature rise of 2 ± 0.2K at the nomi- Conditioned and dehumidified outdoor air nal temperature difference of 8K. supplied to the chilled beam through a duct from the air handling unit. Nominal Temperature Difference 8 K temperature difference between the Reference Air Temperature reference air temperature and the mean Average of the induced air temperature on cooling water temperature. the inlet side of a chilled beam.

Open Chilled Beam Room Air Temperature An active chilled beam where secondary The average of air temperatures measured air is taken in into the top of the beam. at 1.1m high, positioned out of the main Open chilled beams are mainly used with- air current from the chilled beam. out a suspended ceiling. Total Length Operative Temperature The total installed length of the cooling Uniform temperature of an imaginary section of a chilled beam, including casing. black enclosure in which an occupant would exchange the same amount of heat Turbulence Intensity by radiation plus convection as in the ac- The ratio of the standard deviation of the tual non-uniform environment. air velocity to the mean air velocity. Used to measure variations in air velocity.

Symbols and Units SYMBOL QUANTITY UNIT cp Specific heat capacity, cp = 4.187 kJ/(kg,K) (water), cp = 1.005 kJ/(kg,K) (air) kJ/(kg,K) L Active length of chilled beam m Lt Total length of a chilled beam, including casing m P Total cooling capacity, P = cp·qm·(θw2 − θw1) W PL Specific cooling capacity of a chilled beam, relative to active length L W/m PN Nominal cooling capacity at ΔθN = 8K W PLN Nominal specific cooling capacity at ΔθN = 8K W/m qw Water flow rate l/s qm Water mass flow rate (qm = ρw · qw) kg/s ρw Density of water (1000 kg/m3) kg/m3 θa Room air temperature °C θr Reference air temperature = induced air temperature °C θp Primary air temperature °C Δθ Temperature difference, Δθ = θr − θw K ΔθN Nominal temperature difference (= 8K) K θw1 Water inlet temperature °C θw2 Water outlet temperature °C θw Mean water temperature, θw = 0.5·(θw1 + θw2) °C qp Primary air flow rate m³/s p Primary air temperature °C ρp Density of primary air (1.20 kg/m3, θ = 21°C) kg/m3

viii

1. CHILLED BEAM COOLING AND HEATING IN A NUTSHELL

Principles Passive chilled beams comprise a heat Chilled beam systems are primarily used exchanger for cooling, and when desired for cooling and ventilating spaces, where for heating. The operation is based on good indoor environmental quality and natural convection. The primary air is individual space control are appreciated. supplied to the space using separate dif- Chilled beam systems are dedicated out- fusers either in the ceiling or wall, or al- door air systems to be applied primarily ternatively through the raised floor. in spaces where internal humidity loads are moderate. They can also be used for Best suited for: heating. The chilled beam system provides excellent thermal comfort, energy conservation Active chilled beams are connected to and efficient use of space due to high heat both the ventilation supply air ductwork, capacity of water used as heat transfer and the chilled water system. When de- medium. The system operation is simple sired, hot water can be used in this system and trouble-free with minimum mainte- for heating. The main air-handling unit nance requirements. The beam system supplies primary air into the various design complements the flexible use of rooms through the chilled beam. Primary available space, whilst the high tempera- air supply induces room air to be recircu- ture cooling and low temperature heating lated through the heat exchanger of the maximise the opportunity for free cooling chilled beam. In order to cool or heat the and heating. room either cold (14−18°C) or warm (30−45°C) water is cycled through the Typical applications for beam systems are: heat exchanger. Recirculated room air Cellular and open plans offices and the primary air are mixed prior to Hotel rooms diffusion in the space. Room temperature Hospital wards is controlled by the water flow rate Retail shops through the heat exchanger. Bank halls

Closed active chilled beam Open active chilled beam Passive chilled beam

Figure 1.1 Operation principle of closed active, open active and passive chilled beams. In active chilled beams the primary air supply induces room air through heat exchanger where as in passive chilled beam the operation is based on natural convection.

Due to dry cooling operation the beam tems or wet operating cooling systems system is used where the internal humidity (e.g. fan coils) are recommended. loads are moderate, the primary air is dehumidified and any infiltration through the Operating range: building envelope is limited and controll- The active chilled beam system can be ed. Active chilled beams provide an option used when the total sensible cooling to integrate lighting and other building (air + water) requirement is under services with the air conditioning units. 120 W/floor-m² in comfort conditions. The optimum operating range, when good Less suited for: thermal comfort in sedentary type occu- Spaces in which high ventilation rates are pations is required, is 60−80 W/floor-m². required, (i.e. where heat loads and con- The active chilled beam system is typi- taminant loads from occupants are con- cally a dedicated outdoor air system, current) such as conference areas, meet- where primary airflow rates are between ing rooms and classrooms, and where all- 1.5 – 3 l/s,floor-m². Passive chilled beams air systems are more practical. Demand can be used when total sensible cooling based variable airflow systems (VAV) are requirement is 40 − 80 W/floor-m². recommended if heat and contaminant loads vary strongly all the time. Higher cooling requirements can be met, where optimal thermal comfort is not re- In spaces, where internal humidity loads quired or where the occupancy type is not are high, or increased risk of infiltration sedentary (for example in copying rooms, exists e.g. through open doors, all-air sys- computer rooms etc.).

Figure 1.2 Examples of active and passive chilled beam installations.

2. THEORETICAL BACKGROUND

2.1 Heat Transfer The structure and colour of the surfaces have virtually no significance for low An individual’s heat exchange with the temperature radiation as regards its ca- surroundings primarily occurs in three pacity to emit and absorb thermal radia- ways, these are: tion, with the exception of untreated metal surfaces. Examples of sources of heat emission through radiation to low temperature radiation are panel radia- surrounding areas or to free space tors as well as ceiling and floor heating/ heat emission through convection cooling systems. to the surrounding air heat emission through 2.1.2 Convection the evaporation of fluid. If a surface is warmer than the room air it emits heat to the room air. In the same A fourth form of heat exchange can also way, the room air emits heat to a surface occur through conduction to fixed or that is colder than the room air. This form floating objects in direct contact with the of heat transfer is called convection, and body. However, in normal cases this is so is divided into: small it is negligible. Natural convection 2.1.1 Radiation Forced convection Radiant heat is constantly emitted from warmer to colder surfaces and increases Natural convection is obtained through with the temperature difference between the density differences of the air in the them. The radiant heat exchange is primar- different layers, which are created by the ily dependent on the following factors: temperature differences between the air and the objects against or around which the size and location of the surfaces and the air flows. the view factor in relation to each other the temperatures of Forced convection is heat transfer in a the individual surfaces fluid due to motion induced by mechani- the character of the surfaces, which cal means such as a fan. determines the emission and absorption factors, i.e. the ability to emit and 2.1.3 Evaporation absorb radiant heat. Evaporation heat is expended when a liq- uid changes to a gas state. When a person As the room surfaces and conventional perspires this latent heat is transferred by heaters have relatively low temperatures, the body surface, which then cools. Heat an individual’s heat transfer with sur- transfer through evaporation and convec- rounding surfaces takes place in the form tion also takes place during breathing. of long wave, low temperature radiation.

Figure 2.1 Radiant heat transfer occurs between all surfaces of differing temperatures. Convection occurs when air moves along a surface. Natural convection is obtained through the density differences of air, and forced convection e.g. fans.

Heat emissions due to evaporation are de- Specific conductance of the heat ex- pendent on the room air temperature but changer depends on coil and pipe dimen- also on the absolute humidity of the room sions and coil width. air. At average temperatures between approximately 18°C to 25°C with normal Convective heat transfer properties de- relative humidity 20−50% this effect is pend on primary airflow and induction small for sedentary persons. If the humid- airflow rates. Induction rate depends on ity level rises to 60% RH and above, the the type and number of supply air nozzles. skin surface becomes clammy and evaporation is difficult. Inlet water and room temperatures af- fect the mean temperature difference be- 2.2 Heat Transfer Efficiency in tween the air and the water in the heat Chilled Beams exchanger.

Heat transfer within chilled beam occurs Water is a much more efficient heat car- primarily by convection via the heat ex- rier than air. Therefore high airflow rate changer. and consequently large duct work are needed to provide the same cooling effect The heat exchanger is typically a coil with as water. The specific heat capacity per copper pipes and aluminium fins con- kg of water is 4.2 times higher than the nected to the cooling / heating water sys- specific heat capacity of air. tems. In active chilled beams heat transfer ) 100% W is enhanced by forced convection gener- (

L 80% ated by high induction effect of primary P 60% air supply. The heat transfer in the ex- 40% changer depends on several variables. 20%

0% 0 0.11 Water mass flow rate is selected to 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.12 0.13 0.14 0.15 q (kg/s) achieve a desired outlet water tempera- m ture for a given inlet water temperature Figure 2.2 The specific heat transfer of a and to ensure efficient heat transfer by chilled beam. Water flow rate (qm) should be turbulent to ensure effective heat transfer (PL) maintaining turbulent flow conditions but after a certain point any increase of water with sufficient water flow velocity. flow rate does not improve the heat transfer.

The water flow rate inside the pipe should The on/off controller has two stages: “on” be high enough to ensure a turbulent flow (valve fully open – full flow of water) or in design conditions. The heat transfer is “off” (valve fully closed – no water significantly more effective in turbulent flow). An on/off actuator takes 3−5 min- flow than in laminar flow. However the utes to open and close the valve, and chilled beam heat exchanger has an opti- therefore provides reasonable stability in mum specific capacity above which the room temperature. higher water velocity does not increase the cooling output. The proportional (P) controller is modulating the position of the valve and the Table 2.1 Minimum water flow rate with dif- water flow continuously. The P-controller ferent pipe diameters to ensure fully turbulent is associated with a proportional band (P- flow. band), typically 1−3°C – which represents Outside Water Minimum water the deviation from the temperature set diameter velocity flow rate (mm) (m/s) (kg/s) point that produces 100 % control signal (valve fully open). The P-controller en- 10 0.28 0.016 sures a stable control and continuous wa- 12 0.23 0.018 ter flow. P-controller does not eliminate 15 0.18 0.024 the offset from the set point.

18 0.15 0.030 The PI-controller is a proportional con- 22 0.12 0.038 troller with an integrating-function that increases the gain and eliminates the off- 2.3 Room Control set from the set point temperature over time. However, in the cooling season The objective of room control is to mini- when cooling is only required for part of mize the difference between the ac- the day, there is actually little or no dif- tual/controlled room temperature and the ference between P- and PI-control. end-user defined set point temperature.

There are two basic types of controllers used with chilled beam cooling system: self-acting controllers and electronic controllers.

There are different solutions for control- ling room temperature in chilled beam installations:

On/off time proportional on/off Figure 2.3 Room temperature controls can be proportional (P) integrated inside the chilled beam or more typi- proportional-integrating (PI) cally installed on the wall.

3. ROOM AIR CONDITIONING SYSTEM SELECTION

PROPERTIES OF CHILLED BEAM SYSTEM Low life cycle costs:

Low maintenance cost

Good energy efficiency

Free cooling possible in cold and temperate climate

Hygienic system

No filters to be changed or cleaning of drain pans for condensate

Easy cleaning of coils and surfaces, only once in every 5 years

Chilled beams operate with a dry cooling coil

No condensate collection system

Primary air should be dehumidified in the air handling unit and/or

Control of water temperatures is needed to avoid condensation

Building conditions when chilled beams are used:

Cooling demand in the space is less than 80 W/floor-m² (max 120)

Heating demand less than 40 W/floor-m²

Limited infiltration through building envelope

Special attention to the building management system if windows are openable

3.1 Overview of Different Different systems have different proper- Room Units ties with respect to thermal and acoustic performance, operation, maintenance and There are a variety of air conditioning investments. systems (air-water systems), where water is used as the heat transfer medium for The chilled beam system promotes excel- cooling. The most common room air con- lent thermal comfort, energy conservation ditioning units and arrangements in these and efficient use of space due to the high systems are: heat capacity of water used as the heat Fan coil unit transfer medium. The operation principle High pressure induction unit (floor or of the system is simple and trouble-free, ceiling mounted) because the chilled beam system does not Climatic ceilings use fans which consume energy and may • Chilled ceilings break down. In active chilled beam sys- - Ceiling panels tems ventilation is integrated in the room - Plastic pipes covered with plaster units and no separate equipment for room • Chilled beams air distribution is needed. - Active chilled beams (open and closed) Maintenance requirements are minimal - Passive chilled beams because there are no filters to be changed - Integrated service beams (active or any condensate collection system to be or passive beam) cleaned annually. It is recommended that

Single user license only, copying and networking prohibited. All rights reserved by REHVA. 3. ROOM AIR CONDITIONING SYSTEM SELECTION the beam system is vacuum-cleaned every ed with efficient solar shading to limit the 3 − 5 years, and the control system opera- total room cooling demand to less than 80 tion checked at the same time. (max 120) W/floor-m², particularly on the south façade spaces. Beam system design complements the flexible use of the available space, whilst 3.3 Life Cycle Cost (LCC) the high temperature cooling and low When making a decision between the dif- temperature heating maximise the oppor- ferent systems, the life cycle cost analysis tunity for free cooling and heating. The should be performed. Even though the final selection between systems depends investment cost presents about 80% of the on the design of the building, its spaces overall life cycle cost with a life cycle of and their use, as well as the desired qual- 15 years and respectively 50% with a life ity level of indoor climate conditions and cycle of 50 years; the saving potential in life cycle cost. energy, replacement and maintenance costs is still significant. It is difficult to 3.2 Conditions for Chilled Beam give any general values of life cycle cost Applications for different systems, as the result of LCC The operation of all climatic ceiling ap- is very much dependent on the design of plications (chilled beams and ceilings) is the building, climatic conditions etc. For based on dry-cooling operation and typi- this reason it is recommended to make a cally the units or arrangements do not life cycle cost analysis of each building include any condensate collection system. individually. This means that temperature of heat transfer surfaces has to be higher than the dew The investment cost of the chilled beam point temperature of the room air. For system is influenced by the flexibility of this reason the humidity in these build- the space. When beams are installed ings has to be controlled. In most cases lengthwise in the room, the typical chilled this means, that the outdoor air has to be beam installation is one beam in every dehumidified by being cooled in the cen- second or third module. This means the tral air-handling unit. minimum flexibility of about 0.9 m.

The building envelope should meet the When beams are installed crosswise the best National Standard of Air tightness to individual beam can be as short as 0.6m, limit the infiltration through the building and in consequence only has minimum envelope. If openable windows are used, flexibility. However such short lengths then special attention should be paid to the raise the investment cost due to the in- control system of the water temperature to creased number of duct and pipe connec- avoid condensation on the chilled beam. tions, as well as valves and control dampers. This is why it is more cost-effective to Chilled beams have a limited cooling ca- install either longer beams, or use a mix- pacity when high thermal comfort re- ture of shorter and longer beams e.g. alter- quirements of spaces are set. Conse- nating beam length equal to width of one quently all fenestration should be provid- space module and two space modules.

Figure 3.1 In lengthwise (left) installation there are often less pipe and duct connections with same module division, because there is only one beam in every second or third module, while in crosswise installation (right) there is typically one beam per module. The smaller the module division is, the more expensive the beam installation is.

The installation time of a chilled beam is (wax bulb actuators may need replace- about 1 hour. Transportation costs are ment earlier). often included in the purchase price, but if not, 5 to 20% can be added depending Life cycle costs depend on local condi- on the distance between the building site tions and are project specific, and highly and the manufacturing works. dependant on which cost items have been included in the analysis. Accordingly the Estimating energy, maintenance and re- cost difference between the different sys- placement costs is laborious. Energy costs tems is more significant and more reliable include typically heating and electric en- than the absolute cost level. ergy costs. Annual energy consumption and energy price increases should be Use of chilled ceilings and beams has a taken into account as well as the interest positive effect on the energy consumption rate and calculation period. The energy of buildings. Since water is primarily used consumption should be calculated with a as an energy carrier instead of air, the sys- dynamic energy simulation program. tem is using energy efficiently. Since water is the primary energy carrier, the sys- Chilled beams and chilled ceilings require tem is more energy efficient than an all air only minimum maintenance. The finned system. Additionally it is possible to fur- coil of the beam should be vacuum- ther improve the overall efficiency by us- cleaned every 3−5 years and the operation ing higher cooling water temperatures and of room controls should also be checked lower heating water temperatures than are at the same time. used in air based systems. Even sustainable energy sources (waste heat, ground When replacement costs are calculated, a heat etc.) and free cooling can be utilized maintenance period of 20 years can be in order to improve the energy perform- used for beams, and 10 years for controls ance of the building.

Maintenance Investment Energy

Building automation Electricity Plumbing Cooling Equipments Share of different life cycle Beams Share of different costs over 15 years Ventilation and air conditioning investment costs Figure 3.2 Example of different costs in a Scandinavian office building, where chilled beams are used for cooling in the office spaces, and all-air system in other spaces. [5]

The following investment costs (includ- Piping and plumbing ing purchase price, installation and trans- • Cooling pipe work portation costs) should be taken into ac- • Heating pipe work and radiators count in life cycle cost calculations. • Condensate collection systems Building Automation (drain pans and drains) • Building automation and room con- Electricity consumption and trol equipment power demand Ventilation and Air Conditioning • HVAC electricity components • Air handling units, fans, and ductwork (fans, chiller, pumps etc.) • Room equipment, chilled beams, fan Extra building costs coils, VAV units, re-heat coils • Suspended ceiling and raised floor Cooling and heating Reservations for modifications during • Water cooling equipment the building process (%). • Central heating units

Fan coil in 300 rooms, 20-year life cycle: Filter change: €25/filter twice a year € 300.000 15 min to replace @ €20/hr € 60.000 Cleaning of condensation system: 3 times/year @ 15 min € 90.000 Motor replacement: €200/motor € 60.000 2 h work @ €20/hr € 12.000 Fan coil replacement: € 1000/ unit € 150.000 Total € 672.000

Chilled beam in 300 rooms, 20-year life cycle: Cleaning of chilled beam: once in every 5 years á 15 min @ €20/hr € 6.000 Difference in maintenance and replacement costs € 666.000 Figure 3.3 Example of maintenance and replacement costs of a fan coil system and chilled beam system.

4. CREATING GOOD INDOOR CLIMATE WITH CHILLED BEAMS

PRACTICAL GUIDELINES − Comfortable indoor environment can be achieved when:

Cooling capacity of active chilled beams is typically 250 W/m (max 350 W/m) and passive chilled beams 150 W/m (max 250 W/m) to avoid draughts in the occupied zone

Highly insulated airtight windows with effective solar shading are used

Window draught (radiation and downward air movement) in cold seasons is eliminated

Heating capacity of active beams is typically150 W/m to create sufficient mixing between the supply air from the beam and the room air

Operation is designed taking into account the conditions during seasons (winter, summer, intermediate season)

An efficient control system is used

Chilled beams are installed and placed correctly in the space.

− Be aware of increased risk of draught if cold air from chilled beams is supplied towards the cold window surface or directly down to the occupied zone.

− Chilled beams installed above the door can create draught problems if the internal loads near the window are strong enough to bend the air jet from the beam to the occupied zone.

− Passive and open active chilled beams installed in the suspended ceiling always require sufficiently large openings in the ceiling for the induced room air path.

− When demonstrating the operation of chilled beams with full-scale mock-ups or computational fluid dynamics (CFD) simulations, the input parameters should be adequately defined, especially the boundary conditions of beam when using CFD.

4.1 Types of Chilled Beam a perforated ceiling. Supply air can be in- Systems troduced either from high or low level.

4.1.1 Passive Chilled Beams Heat transfer from passive beams occurs mainly by natural convection with a minor part by radiation. Warm room air in contact with the cooled surface of the heat exchanger flows downwards through the beam into the room. Passive chilled beams are not connected to the ventilation system Figure 4.1 Operation principle of a passive and can be positioned fully exposed, re- chilled beam is mainly based on natural con- cessed within a suspended ceiling or above vection.

Ventilation air supply (outdoor air) ar- positioning, it is possible to supply air in rangements need to be designed carefully one or two opposite directions. in order not to interfere with the operation of passive chilled beam. When the air is An active chilled beam can be either open supplied using ceiling diffusers, the air jet or closed with an integral induced air should not obstruct the convective flow of path. In closed chilled beams induced passive chilled beam. In some cases room air flows directly through the heat where this could be exploited to prevent exchanger so that is not circulated via the downdraught from a beam, the reduction suspended ceiling. in capacity of the chilled beam should be taken into account (e.g. in full scale 15 l/s 18°C mock-up).

Passive chilled beams can also be used with under floor supply or with sidewall displacement terminals. This arrangement typically creates a good mixed flow sys- 65 l/s 18.5°C tem, where the convective down flow 50 l/s from passive chilled beams mixes with 24°C the low velocity air supply. 65 l/s 18.5°C Room air quality can be improved using high supply airflow rates. However, the 15 l/s size and number of diffusers should be 18°C selected so that the air velocities in the occupied zone are low. 50 l/s 24°C 4.1.2 Active Chilled Beams Figure 4.2 Active chilled beam operation is based on induction of room air through the Active chilled beams combine the supply cooling coil. The induction rate varies between of ventilation air (outdoor air) and cool- 1:3 and 1:5 depending on the design. ing in order to enable effective heat transfer due to forced convection, and ensure 4.1.3 Perimeter Passive Chilled Beams good air distribution also at high cooling Perimeter passive chilled beams are in- capacity levels. Primary air is supplied stalled close to glazed façades or win- into the space via a supply air plenum dows, and are designed to offset solar through nozzles along its length. The gains in the perimeter zone and minimise supply air jet induces room air through the depth of the zone of high cooling de- the heat exchanger. mand. They minimise the disruptive effect that solar gains can have on air tem- The mixture of outdoor air and induced perature and air circulation away from the room air is supplied into the room perimeter, which is especially important through the longitudinal slots along both where displacement ventilation and/or sides of the beam. Depending on re- chilled ceilings are used. A further advan- quirements, available space and beam tage of locating chilled beams in the

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook perimeter is that any warm plume rising while reducing costs. Single source re- from the window or blind enhances the sponsibility lowers risk and reduces the air-water temperature difference in the need for co-ordination. In addition, the chilled beam and this raises its cooling space achieves architectural finish when performance. [7] fewer separate pieces of equipment are fixed to ceiling and walls. Often available room height is increased, as no suspended ceiling is needed. Lighting heat extracted in exhaust

Chilled beam Chilled ceiling panels

Displacement ventilation

Figure 4.3 An example of a perimeter chilled beam installation. It can be used with different kind of climatic ceilings as in this illustration, with chilled ceiling panels and under floor supply but also with active or passive chilled beams.

4.1.4 Integrated Service Beams Traditional chilled beam installations have chilled beams as the ventilation, cooling and heating solution, but an integrated service beam concept proposes an all-in-one solution for all ceiling mounted room technical services like down and/or up lights, exhaust, sprinklers, PA/VA Figure 4.4 Different room services can be integrated into the chilled beam at the factory. speakers, PIR sensors, smoke detectors, power and IT cabling and connections. The integrated service beam concept is 4.2 Comfortable Indoor Climate suitable for both active and passive beams with Chilled Beams for both flush and exposed mounted in- Indoor climate target values should be stallations. taken into account, when defining design values for chilled beam systems. Specific The service beam is an integration of aes- cooling capacity and primary airflow rate thetics and economics. Pre-assembly of should be limited to the range where all desired services at the factory in- proper operation conditions and comfort- creases installation speed and quality able thermal conditions can be ensured

Single user license only, copying and networking prohibited. All rights reserved by REHVA. 4. CREATING GOOD INDOOR CLIMATE WITH CHILLED BEAMS e.g. by avoiding too high air velocities in The required cooling capacity should always the occupied zone. The higher the spe- be calculated using dynamic simulation cific cooling output, the higher the induc- software taking into account the simultane- tion rate (typically 1:3−1:5) and therefore ous heat loads as well as the transient heat the risk of draught is increased with high transfer effects of the thermal mass of the linear cooling capacities. construction. Unnecessary over-sizing of the system increases the investment costs. The To ensure comfortable conditions in spaces, intentional over-sizing for future flexibility it is recommended that the building is de- is realised by paying attention to the sizing signed so that heat loads can be maintained of water flow rates and ensuring the stable below 80 (max 120) W/floor-m². room temperature control.

Table 4.1 The following values can be used as a guideline the interdependency between the maximum cooling output of the chilled beam system and the supply airflow rate. Actual values need to be checked case by case using the data of selected beam type and model. Airflow Rate Cooling Capacity ( l/s,m²) (W/m²) 1.5 … 70 2 … 90 3 … 120

Table 4.2 Recommended indoor climate target values. These values are based on good indoor climate level of international standards and recommendations like EN ISO 7730 and CEN report 1752, noticing some limitations of chilled beam system. Summer Winter Comfort PMV -0.5…+0.5 -0.5…+0.5 Temperature Operative room air temperature 24.5 ± 1.5°C 22 ± 2°C Vertical air temperature difference (0,1…1,1 m) < 3°C < 3°C Radiant temperature asymmetry of windows < 23°C < 10°C Radiant temperature asymmetry of ceiling < 14°C < 5°C Floor surface temperature 19…26°C 19…26°C Air Quality Outdoor air requirement per floor area 1.5…3 l/s,m² 1.5…3 l/s,m² Outdoor air requirement per person 8…20 l/s,person 8…20 l/s,person Air Velocity Draught rating (DR) < 15% < 15% Average air velocity in the occupied zone (PMV=0) 0.18 m/s 0.15 m/s Maximum air velocity in the occupied zone 0.23 m/s 0.18 m/s Air Humidity Relative humidity 30…55% 25…40% Acoustics Sound level requirement NR15-NR30 NR15-NR30

Figure 4.5 The design cooling capacity of chilled beam should be defined based on hourly solar, occupancy, light and equipment loads. The cooling demand can be calculated by taking into account the thermal mass of constructions and, when desired, the night ventilation.

Satisfactory heating operation of active lected to allow for higher primary airflow chilled beams is by selecting units with and water flow rates to compensate po- low specific capacity so that the warm tential increases in heat loads within the mixed airflow mixes well with the room space. The beam design and arrangement air. High supply air temperature and high can allow for both future partitioning re- specific heating capacity decrease the ven- quirements and the modular design of the tilation efficiency and increase the tem- space. perature difference between the floor and ceiling. Cold and extensive window sur- Since both active and passive chilled face increases the risk of stratification. beam operation is sensitive to internal Attention should be paid to the fabric, and conditions, design parameters should be size of the fenestration to keep the heat considered not only for summer and win- losses moderate and surface temperatures ter conditions but also for intermediate close to the room air temperature. seasons, when the system is often operating in cooling mode due to high internal If possible the chilled beam arrangement and external heat loads, although the ex- should be designed to allow for future ternal weather conditions are closer to layout changes within the space. This will winter conditions. This is especially im- apply to speculative office buildings, portant when the airflow from the active owner-occupier developments and refur- chilled beam is directed towards the cold bishments. Chilled beams may be se- window surface.

Table 4.3 Recommended design values for chilled beam system. Cooling Heating Cooling and Heating Optimum heat loads / losses 60…80 W/floor-m² 25…35 W/floor-m² Maximum heat loads / losses < 120 W/floor-m² < 50 W/floor-m² Specific capacity of passive beam above occupied zone < 150 W/m − Specific capacity of passive beam outside occupied zone < 250 W/m − Specific capacity of active beams (highest class of indoor climate) < 250 W/m < 150 W/m Specific capacity of active beams (medium class of indoor climate) < 350 W/m < 150 W/m Supply air Specific primary air flow rate of active beam 5…15 l/s,m 5…15 l/s,m Supply air temperature 18…20°C 19…21°C Pressure drop of active beam 30…120 Pa 30…120 Pa Room air Reference air temperature (air into the beam): active beam Room air temp. Room air temp. + 0…2°C Reference air temperature (air into the beam): passive beam Room air temp. + 0…2°C − Inlet water Water flow rate with pipe size of 15 mm (turbulent flow) > 0.03…0.10 kg/s > 0.03…0.10 kg/s Water flow rate with pipe size of 10 mm (turbulent flow) > 0.015…0.04 kg/s > 0.015…0.04 kg/s Inlet water temperature 14…18°C 30…45°C Pressure drop 0.5…15 kPa 0.5…15 kPa

The successful operation of passive beams room air and inlet water increases the is dependent on the correct positioning of cooling outlet of the passive beam is also the beam with respect to the internal heat increased. The system operation is reliable loads. If the loads are located right under and the room temperature is kept within the beam, the convective flow of the heat the desired range. To avoid heating and loads may obstruct the natural convection cooling at the same time this solution through the coil. On the other hand the should be combined with free cooling by correct positioning may slightly improve air handling unit heat recovery. the performance of passive chilled beams. 4.3 Room Construction Design A chilled beam system (mainly passive Requirements beams) can also be partly designed as a self-regulating system without a room con- When installing open active chilled beams troller. The water inlet and outlet tempera- or passive chilled beams into a suspended tures (typically 19/22°C) are selected close ceiling, a minimum clearance between the to the minimum room air temperature. top of the beam and soffit should be pro- This ensures that with minimum heat load vided for a sufficient return air path. level the room is not becoming too cold. Once the heat loads start to increase, the Shadow gaps, dummy beam sections and room air temperature rises. As the tem- transfer grilles are recommended for return perature difference between the ambient air path arrangements. The return air path

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook should be placed at the unit’s short side if occupants, as well as to prevent any down possible. The net free area of return air draught from the internal window surface. path should be at least 0.1m² per linear active chilled beam meter and a minimum Whenever chilled beams are used for 50% of the surface area of passive beams. heating with extensive glass facades, spe- Secondary air recirculation into the ceiling cial attention should be paid to window void only through the air handling light construction. There are several options to fittings is not recommended due to the increase the surface temperature of win- higher air pressure drop incurred. dow and minimise the draught created by the window.

As long as the window internal surface temperature is high enough (at least 14°C) the risk of draught is small. In practice this means that the average U- Figure 4.6 A minimum clearance between the value of window (frame and glass areas) top of the passive chilled beam and soffit should be provided for a sufficient return air should be around 1.2 W/m²K. path. A radiant panel or passive chilled beam The selection of windows critically af- above the window cannot measurably fects the indoor climate conditions. increase the surface temperature of window. However it lowers the radiant tem- The heat transmission coefficient of win- perature asymmetry near window, and dow should be sufficiently low to ensure because air is warmer above the window, that during the winter the internal window the air temperature underneath the win- surface is warm enough to avoid direct dow is also higher and thereby reduces radiation between the window and the the draught.

Table 4.4 Air velocity underneath the window created by cold window surfaces. However in a typical office application the air velocity underneath the window is not important, but it should be studied in the occupied zone 1 meter from the window.

Troom (°C) Toutdoor (°C) U-value (W/m²K) Window height (m) Tsurface (°C) V (m/s) 21 −20 1 1.5 14.9 0.22 21 −20 1 2 14.9 0.24 21 −20 1.5 1.5 11.8 0.26 21 −20 1.5 2 11.8 0.31 21 −5 1 1.5 17.1 0.18 21 −5 1 2 17.1 0.2 21 −5 1.5 1.5 15.2 0.21 21 −5 1.5 2 15.2 0.23 21 −5 2 1.5 13.2 0.24 21 −5 2 2 13.2 0.27

A warm radiator underneath the window ensure proper cooling output, but on the prevents down draught. It is also impor- other hand small enough to avoid down tant to remember that there should be no draught directly from beam. obstacles close to the window (table at least 100 mm from window). Heating 4.4.2 Positioning of perimeter chilled strips (electrical) underneath the window beams or heated window glass can also be used. The performance of perimeter chilled beams has been shown to be very sensi- There are also other constructional tech- tive to the design and configuration of the niques to reduce down draught from a perimeter area including suspended ceil- window. It can be divided to several sec- ings and window blinds. In practice this tions when turbulence between each win- has often led to poor performance and dow sector decreases the velocity under- conflict with architectural and aesthetic neath. Obstacles like cable chases have requirements. the same effect. The following guidelines should mini- 4.4 Positioning of chilled beams mise the negative impact of interaction of thermal plumes and building construction 4.4.1 Positioning of passive chilled beams and ceiling elements. Passive beams should not be installed directly above fixed working positions, Internal roller blinds are more effective at because the velocity created by natural guiding the thermal plumes from solar convection is highest underneath the gains to perimeter chilled beams than beam. If the beam is situated above the slatted horizontal blinds. If the blind is window or above other high convective not installed in a box then the gap be- heat loads, the possible reduction of cool- tween the top of the blind and the under- ing output should be taken into account. side of the building frame should be as small as possible.

The installation of ceiling tiles below chilled beams restricts the free flow of air into and out of the ceiling void and therefore through the chilled beams. Ceiling tiles should therefore have at least 50% free area and hole size maximised (for example 10 mm diameter). Ideally no Figure 4.7 Passive beams should always be ceiling tiles should be fitted or louvered positioned outside of occupied zone. tiles should be used below perimeter chilled beams. The risk of draught can be minimised by positioning the passive beam above the Lowering the chilled beams and ceiling perforated ceiling, in which case the per- relative to the underside of the building forations in the ceiling should be large perimeter frame results in more of the enough (approximately 50% free area) to thermal plume being captured and

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook directed into the ceiling void. This pro- This positioning is acceptable only when vides both increased cooling performance it is agreed to limit the occupied zone. and improved thermal comfort. [7]

4.4.3 Positioning of active chilled beam The recommended location of active beams is above work places, because velocity is lowest precisely underneath the beam (if the throw pattern of the beam is horizontal). If the beam is positioned near the wall, the asymmetrical / unidirec- tional throw pattern is recommended.

The lowest velocity conditions for all seasons can be created, when chilled beams are installed lengthwise in the space. This normally ensures the use of longer beams, which means lower cooling capacity requirement per linear meter.

Lengthwise installation is also beneficial Figure 4.8 Active beams should be positioned in intermediate seasons, when window above the work place in the space to ensure surface is still cold but due to internal the lowest air velocities in all seasonal condi- loads cooling is required in the space. In tions. the crosswise installation the cool supply air is discharged towards the cold window surface increasing the velocity underneath the window.

The beam installation above the door is sensitive to internal convection flows if the supply air is discharged towards the window. Due to the long distance from the beam to the opposite wall, the supply air jet may be interfered by uprising convective flows from heat loads and de- flected directly into the occupied zone.

When active beams discharge downwards e.g. from above the door, the distance from the beam to the occupied zone must Figure 4.9 Room air velocities in the interme- be long enough to avoid high velocity diate season with the same beam installed ei- close to the floor in the occupied zone. ther crosswise or lengthwise in the room. [11]

describing physical phenomena are solved numerically. Both options are ca- pable of demonstrating the velocities and temperatures in the space in steady-state conditions, as long as the input parameters are correct.

If there is no real boundary data of chilled

beam available (given by a manufacturer), the mock-up then gives more reliable information.

It is critical to model the internal conditions and external solar loads as naturally as possible. A chilled beam system is sensitive to convective flows and for this

reason the ratio of convective and radiant Figure 4.10 Possible risk of room loads influ- heat transfer should be correct when encing the throw pattern of the beam. In the top picture there is no internal load in the space demonstrating the process in the space. and in the bottom picture the room is occupied The surface temperature and area of each and the window surface is warm. [11] mock-up of heat sources should be at the correct level. For the same reason the po- 4.5 Demonstration of Indoor sitioning of all the loads should be identi- Climate Conditions cal to an actual case. Using the even distribution of loads inside the space, or When chilled beams are used within the transferring all the loads through the wall normal operation range and in normal construction (as in a standard capacity installation positions, any special demon- measurement), the velocity and tempera- strations of operation is not necessarily ture values measured in the occupied needed. But if the operational parameters zone are unrealistic. of a chilled beam are close to or beyond the recommended limits, and if the posi- In CFD simulations the critical issue is tioning of the beam is critical, it is rec- the boundary conditions of selected beam. ommended to demonstrate the operation This is why whenever CFD simulations of the product in the specified design are used; the product boundary conditions conditions. specified by the manufacturer should be used. The difference between simulated There are two options to demonstrate the and actual velocity and temperature val- operation: full-scale mock-up tests and ues can be remarkable if using generic Computational Fluid Dynamics (CFD) product model. simulations. CFD-simulation equations

Figure 4.11 Example of full-scale mock-up, where internal loads are simulated with dummies giving the correct ratio of convective and radiant load. Window wall and floor close to window is heated to give external loads to the space. Air movements are visualized with smoke.

When ordering a full-scale mock-up or Specification of solar gain through the CFD demonstrations the following items window (surface temperatures of walls should be specified: and floor) Target of the test Tested products, locations and (what problems need to be solved) manufacturer Sizes of the space Details of different test cases: (length, width, height) • Room air temperature Window construction • Supply air temperature and airflow rate (type, width, height and heat • Water inlet temperature and water transmission coefficient, solar shading) flow rate External temperatures Velocity and temperature measurement (summer / winter) grid and heights e.g. 0.1 m, 0.6 m, 1.1 m, Furniture and ceiling lay-out 1.4 m and 1.8 m (measurement points to Specification of internal loads find maximum velocity need to be (also positioning) defined e.g. by smoke during the test).

5. CHILLED BEAM SYSTEM DESIGN

PRACTICAL GUIDELINES − Design the chilled beam system based on real cooling requirements. Overdesign of the system makes it more expensive and decreases comfort.

− Primary air should be dehumidified in most cases and the airflow rate must be high enough to absorb the humidity generated in the space and fulfil the hygienic needs (1.5 – 3 l/s,floor-m²) (5−15 l/s,beam-m). Very high primary airflow rates increase the risk of draughts in the occupied zone.

− Try to use only a few different type of beams (type, length, nozzle size etc.) in order to make the tendering process, logistics on the construction site and maintenance of building easier.

− Oversizing of heating system may prevent the proper operation of chilled beams used as a heating unit. Use as low an inlet water temperature as possible (max 45°C)

− Chilled beam systems can be used also in a hot and humid climate, as long as infiltration is controlled, primary air volume is high enough and morning start- up is in control.

− Condensation must be prevented in chilled beam systems by:

Sufficiently high inlet water temperature (14°C or higher)

Dehumidification of primary air (especially when the outdoor air temperature is above 22°C)

Insulating valves and pipes

Using condensation sensors on the pipe surface

Raising the chilled water temperature or switching off valves locally if there is an increased risk of condensation

− Distribution pipework dimensions are larger due to dry cooling system operation (low temperature drop across the coil 2 – 4°C)

− Typical room air temperature control is time proportional on-off control with 2-way valves.

− Chilled beam system increases the opportunities to use free cooling and sustainable heat sources.

5.1 Cooling with Active Chilled heat loads together with internal gains Beams can be calculated. The thermal capacity of the construction should be taken into Having defined the design room tempera- account in cooling load calculations by ture (normally between 23−26°C in the using dynamic simulation software. The summer) and established the external de- difference of external heat loads through sign ambient conditions, external sensible windows based on dynamic simulation in

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook different geographical locations in zone. The use of protection against exces- Europe, is smaller than those generally sive solar gain is therefore highly recom- used in design practice. mended (special glass, different types of shading etc). Overdesign of the system increases the installation cost, and even if the thermal The chilled beam system primary airflow comfort criteria is fulfilled, the percent- rate is defined to satisfy comfort condi- age of satisfied occupants is reduced due tions, minimum ventilation requirement to increased air velocities in the occupied and internal humidity level.

Figure 5.1 The chilled beam system creates comfortable air velocity and temperature conditions in the space when the overall building and chilled beam system is designed correctly.

] 120 floor 110

100

90 Helsinki 80 Paris Rome Cooling required [W/m² required Cooling 70

50 , ntis.green ntis.green ntis.green Low-emis., A 2xClear, 2xClear, No blinds 2xClear, Blinds 50% Low-emis., A 2xClear, No blinds 2xClear, Blinds 50% Low-emis., A 2xClear, No blinds 2xClear, Blinds 50% West South East Window type and direction Figure 5.2 A study shows the cooling load using different window types and directions in three different geographical areas in Europe. According to this study the difference in the cooling load in different areas is 10−18% depending on the case and the maximum cooling load is 110 W/m²,floor.

The required ventilation rate in a typical of- only, the inlet water temperature must be fice space is 1.5 − 3 l/s,m² (6 – 12 m3/h,m²). selected to avoid condensation. The inlet In order to keep humidity levels within the water temperature (normally no lower design parameters the primary air handling than 14°C) must be selected so that the unit normally requires the facility to de- surface temperature of the cooling water humidify the supply air. The primary air- inlet pipe is above the dew point tempera- flow rate should also be high enough to ture of the room air. absorb the humidity generated inside the space. The cooling water inlet temperature and water flow rate are selected so that an Chilled beam systems normally use a adequate temperature difference between constant air flow and operate with a pri- the mean water temperature and room mary supply air temperature reset by the temperature (Dq = 6 – 10°C) and the re- season (summer: 18 − 20°C and winter: quired cooling capacity can be achieved. 19 − 21°C). Lower supply air temperatures can be used if the room system Cooling water mass flow rate is selected (beam or other heating element) has the so that the flow is turbulent in the normal capacity to also heat the cold supply air in operating situation, typically 0.025 – order to avoid too cold room air tempera- 0.10 kg/s for a ø15 mm pipe. Beams can ture. be connected in parallel or series. Parallel connection is normally used, but for When the specific length (of the heat ex- short-length or low-capacity chilled changer) of the chilled beam and the pri- beams, series connection may also be mary air flow rate are defined, it is impor- used. tant to note that each beam has a minimum operating airflow rate to keep the To suit architectural requirements the minimum pressure inside the beam cham- length of the beam casing can be selected ber, as well as to ensure effective heat longer than the actual capacity requires transfer of the cooling coil and to guaran- (e.g. as long as the room). In this case the tee the operation of air diffusion. On the actual heat exchanger section is sized ac- other hand the primary airflow rate cording to the required cooling load, after should not be too high in order to avoid deducting the cooling effect of the pri- excessive induced air flow which can mary air supply. However it is always cause draughts in the occupied zone. The beneficial to select as few different types typical airflow rate of an active chilled and lengths of beam as possible in each beam is 5 l/s,m – 15 l/s,m. floor or building. It simplifies both the tendering process and the logistics on the Chilled beams are selected with inlet and building site. outlet water temperature differences of typically 2 − 4°C. Water flow rates and In the case of large cold windows, the connection method (chilled beams con- simultaneous operation of both the beam nected in parallel or series) should also be cooling and the under window heating considered. As the chilled beam system is system is recommended. This avoids cold designed to provide sensible cooling draughts from the window, and compen-

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook sates the internal heat loads with cooling. perature is higher than 14°C and height is This increases the operative temperature not more than 1.5 m). and ensures the comfort of the occupants. The energy wasted from the heating ele- 3 ments is recovered by the heat recovery 2.5 system of the air-handling unit. 2 5.2 Heating with Active Chilled Room height (m) Room height Beams 1.5 40 deg.C The design of the heating system begins 1 60 deg.C by defining the required heating capacity. 0.5 74 deg.C In traditional heating systems the design is often based on high safety margins 0 when heat losses are calculated. When a 0 2 4 6 8 10 chilled beam system is used for heating, Temperature difference dT (C) proper system operation cannot be Figure 5.3 Temperature gradient in the space achieved by oversizing the heating sys- with different inlet water temperatures. tem. In a new office building 30 –

45W/m²,floor of heating capacity is typically enough.

If the heating inlet water temperature of a chilled beam is higher than 40 – 45°C 28°C (linear output of an active beam is higher than 140 − 160 W/m) in a typical installation, secondary air is often too warm to mix properly with the room air. The relatively low temperature gradient in the O space raises the air temperature near the 24°C Inlet w ater 36 C floor thus maintaining comfortable thermal conditions, as well as ensuring the energy efficiency of the system (by decreasing the short circuit and thus the exhaust air temperature). 38°C The mixing is also dependent on the window size and surface temperature. The higher and colder the window, the colder the air falling down to the floor, and the 26°C Inlet w ater 55°C temperature gradient between secondary air and room air becomes higher. For this reason using beams for heating is recom- Figure 5.4 IR Measurements of a closed beam mended when the heat transmission of the during heating mode with two different inlet windows is moderate (e.g. surface tem- water temperatures made by KTH in Sweden.

The heating capacity of active beams is When an office room is occupied the in- dependent on the primary airflow rate. ternal heat sources normally reduce the This is why ventilation must be operating required heating output and the tempera- when heating is required. ture gradient stays at an acceptable level.

The heating of static beams is based on 5.3 Active Chilled Beams in Hot the mixing effect of primary air supply and Humid Climates and cold window surface, partly because the warmer upper part of the space is ra- In a hot and humid climate, it is important diating to other surfaces and warming to control the relative humidity concur- them up. rently with the temperature. Decreasing the indoor air temperature and humidity could The temperature gradient between the improve the perceived air quality signifi- cold floor and the warm ceiling is slightly cantly. The results have shown that the ac- mixed by the cold window but is still ceptability of indoor climate increases line- relatively high in early morning. There- arly with decreasing enthalpy of air. fore the ventilation needs to be started early enough to ensure that the warm The use of a chilled beam system in a hot room air near the ceiling is mixed well and humid climate has been studied using before space is occupied. Sometimes it is the case-study approach [14]. Field meas- necessary to close the warm water circu- urements were conducted in two rooms of lation of the beam system to increase the an office building, located in Singapore, mixing of room air at start up. served by a ventilated chilled beam system.

24,0

22,0 Beam Water Inlet Temperature

20,0 Beam Water Outlet Temperature C) o 18,0 Room Air Temperature 16,0

temperature ( Dew Point 14,0 Temperautre

Off-Coil 12,0 Temperature (AHU)

10,0 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 27 of March Figure 5.5 Case study measurement results of an office room during 24 hours in Singapore. With these set points, the objective was to prevent condensation in the beam unit and to achieve dry cooling. The humidity level was high because the supply airflow rate was much lower (39%) than the design specification due to undersized fan capacity. It should be noted that the humidity level was not significantly increased during the night. During the nighttime the dew point was only 1OC higher than the daytime value. [14]

Based on the measurements, it is possible used to control humidity levels and avoid to prevent the condensation in the beam condensation. system and achieve dry cooling. But only if the infiltration is minimized, the supply In order to ensure dehumidification the airflow rate is sufficient to extract humid- supply air during periods of high outdoor ity caused by people, and the control sys- temperatures and high relative humidity, tem has correctly designed and commis- the cooling coil of the air handling unit sioned. Consequently night ventilation is should be sized adequately to meet the not recommended and the exhaust fans total cooling demand including both sen- must also be stopped during the night sible and latent heat load. The supply air time. water content should be so low that the ventilation airflow compensates for the The most critical time to reach dry cool- internal humidity loads, in practice the ing is to maintain the required humidity room air dew point temperature is lower level during the morning start-up period. or equal to the inlet temperature of chilled Condensation can be prevented by start- water in the chilled beam system. ing dry air ventilation about 30 minutes before the water-based cooling by adjust- As moisture will most likely first appear ing the operating hours of the fans and on the valves it is good practice to insulate the chilled water pump of the beam sys- the valves and connecting pipe work lead- tem. ing to the heat exchanger. The system can be further safeguarded with condensation The target temperature and humidity lev- sensors mounted on the surface of the els are the starting point for the system connecting pipe work. If condensation is design. Typically, the target for the room detected then either the inlet water tem- temperature is 23−24°C and 60−65% for perature is raised, the beam cooling water the relative humidity. circulation pumps are switched off, or control valves are switched off locally. How- 5.4 Prevention of Condensation ever in the case of a building with openable windows individual contact sen- Cooled beam systems must be designed sors can be applied to the windows to shut to ensure that there is no risk of conden- off the cooling water supply to that area. sation. This means selecting an inlet water temperature higher than the dew point Studies have shown that the inlet water temperature. The inlet water temperature temperature can be slightly lower than the must be reset accordingly, if the internal dew point of the space before the conden- humidity levels are affected by external sation occurs on the pipe surface and influences. even lower (-1.5°C) before the water droplets start to form. This difference is Dehumidification of the primary supply recommended as a safety margin for un- air by the main air handling unit plant is expected humidity loads.

Outdoor air e.g. in Scandinavia

Room air

Supply air Inlet water to beams

Water temperature in cooling coil

Figure 5.6 Dehumidification process of primary air presented in psychometric chart.

5.5 Air and Water Distribution the chilled beams (14–18°C) is generally Systems significantly higher than the supply water temperature of the air handling unit's A typical active chilled beam system for cooling coil for dehumidification of the cooling is presented in the schematic dia- primary supply air (7−9°C). gram (Figure 5.7). The chilled water circuit for the chilled beams is connected to If chilled beams are also used for heating, the primary chilled water system via a the system has two separate water cir- buffer vessel. Chilled water is continu- cuits, a low temperature (35−40°C) cir- ously circulated the system using a 3-way cuit for the chilled beams and high tem- mixing valve for flow water temperature perature circuit for the air handling unit’s control. The water inlet temperature of heating coil.

Air handling unit

Buffer vessel Active chilled beam

Chiller Thermostatic valve + water radiator

District heating Figure 5.7 An example schematic diagram of an active chilled beam system typically used in Scan- dinavia, where one chiller is providing cooling water both for the air handling unit (7°C) and the chilled beams (15°C).

5.5.1 Distribution Pipe Work ing 10 kPa pressure drop in the coil of the Due to lower temperature difference be- chilled beam, 10 kPa for the control tween flow water and room air (8−10°C) valves and 10 kPa for the pipe work. By in a dry cooling system, the water flow using the final pressure drop over beam rates are higher and the pipe sizes in the coil and beam valve / balancing valve, the distribution pipe work are larger. Distri- balancing by the balancing valves in the bution pipe work is typically sized to a shaft for each floor could be excluded. pressure drop of 50−100 Pa/m in order to enable balancing the pipe work using Copper, steel or plastic pipes can all be small pressure drops in the balancing used. Pipes should be insulated to save valves to avoid noise generation. energy and avoid condensation. If the inlet water temperature is constantly kept The maximum recommended pressure for above the dew point temperature, no va- the distribution system is 35 kPa compris- pour barrier in the insulation is needed.

Due to the lower heat transmission proper- The flow water temperature is controlled ties, plastic pipes may be used without according to the dew point of room or insulation taking care that the flow water exhaust air. The operation of mixing temperature is kept at a sufficiently high valve group is essential for condensation level. prevention. Either 2-way valve with a bypass or 3- way valve is used. The main pipes should be installed at a higher level than the chilled beams to en- 5.5.2 Chiller Plant and Buffer Vessel able the venting of the pipe work e.g. us- In chilled beam systems it is possible to ing automatic venting valves. benefit from the high coefficient of performance (COP) of the chiller plant at the When using 2-way control valves for the elevated flow water temperatures. This water flow control of the chilled beams, can reduce the chiller plant size and run- the pressure control with constant pres- ning costs. sure regulators should be used to avoid the risk of water borne noise. With vari- Cooling is also needed in wintertime, and able speed pumps also pumping energy is for this reason the chiller must be sup- conserved. plied with winter operation equipment.

Alternatively, the pressure difference can The chilled water circuit is connected to also be regulated by mounting a by-pass the primary chilled water circuit via a connection equipped with a balancing buffer vessel. This buffer vessel mini- valve or pressure reduction valve at the mises the frequency of stop/start opera- end of each branch. tions of the chiller plant.

AHU ME TE

TC TE

7 – 14°C 14 – 19°C

Beams 15 … °C

AHU ME TE

TC TE

7 – 14°C 14 – 19°C

Beams 15 … °C

Figure 5.8 Mixing valve group prevents too cold water circulating in the chilled beam system.

Figure 5.9 The efficiency of the compressor can be increased by using a dry cooling system (inlet water 14°C instead of 7°C).

5.5.3 Ductwork and Air Handling Unit However dehumidification of the supply Due to constant airflow and full outdoor air is needed in the cooling coil of air air system the duct dimensions are small. handling unit. The ductwork is proportionally balanced, but also constant pressure controlled When chilled beam duct branches are ductwork zones are use for two reasons: symmetric and the main ducts are large 1. variable flow applications are incor- with low pressure losses (1 − 2 Pa/m), in- porated in the zones dividual balancing dampers are not neces- 2. effective implementation of airflow sarily required. This is beneficial not only adjustment within the zone. in operation (e.g. noise generation and fan

Single user license only, copying and networking prohibited. All rights reserved by REHVA. 5. CHILLED BEAM SYSTEM DESIGN energy) but also in both installation and There are several options for utilising the commissioning. If symmetrical duct de- cold outdoor air. For example, the chilled sign is not possible, similar benefits can be water from the buffer vessel can be circu- achieved by designing constant pressure lated through the cooling coil of the air- ductworks. handling unit during free-cooling operation and heat is transmitted from the chilled water to the supply air. Other al- ternatives are dry air coolers, cooling towers or ground cold energy storages.

Since the chilled beam system is a low temperature (30−45°C) heating system, sustainable heat sources are easier to use than with traditional heating systems; and higher efficiency of the heating boiler is

achieved. A heat pump system is particu- Figure 5.10 Example of traditional and self- larly suitable for heat generation due to adjusting ductwork. its high efficiency at the low temperature levels.

5.6 Use of Free Cooling and If either free cooling or sustainable heat Sustainable Heat Sources sources are considered, the requirements of the systems mentioned earlier, need to A higher chilled water temperature is be taken into account when selecting the used in active chilled beam systems com- inlet and outlet water temperature differ- pared to other systems (e.g. fan coil sys- ences. tems). This provides the opportunity to use various sources of free cooling such 5.7 Room Controls as outdoor air or ground water heat sinks. Free cooling reduces the need for addi- Very basic controls can be used with tional mechanical cooling and will reduce chilled beam systems, because of the long operating costs. During the summer sea- reaction time of chilled beam. This is due son however, a mechanical cooling sys- to the large coil size and low air velocity tem will be required. through the coil, compared to the other air-water systems like fan coils. Chilled beams can be designed and selected to use higher operating tempera- The control principle can be on−off, time tures than typical fan coil systems proportional on−off or modulating. The (14−18°C Vs 6−12°C), increasing the selection of the control system is depend- available free-cooling period. On the ent on the system design. In most cases other hand due to small inlet-outlet tem- all the above mentioned control principles perature difference pumping energy costs provide reliable operation of the system. are higher than in fan coil systems. In cases where the difference between the

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook design and normal operating conditions is sor that registers if condensation forms on large (e.g. the design is based on a much the flow pipe to the chilled beam. higher heat load level than the existing load), time proportional on−off or modu- When the sensor registers condensation on lating controls are recommended. the flow pipe, the electronic dew-point alarm is activated. In the alarm mode, the The room air temperature is maintained two potential-free relays are activated. The by regulating the water flow rate with a relay outputs can be used to shut off the 2-way valve in order to minimise pump- valve and/or to send a signal to an alarm ing costs. system or BMS system that condensation is appearing in the room or zone.

Control valve 5.8 Design Methodology for Chilled Beam System Shut off valve The design of chilled beam systems is twofold: the determination of the design conditions of the space Balancing + shut off valve the selection of the type and length of the chilled beam and definition of other Room thermostat/controller related design parameters.

Figure 5.11 Typical room air temperature con- The first is related to the specific space trol with a chilled beam system. where beams are used. However, the optimum operation of chilled beam system The valves should be made of corrosion- sets some limitations to the space design. resistant brass, specially designed for For this reason the design of the space chilled water applications. and selection of the beam is often an it- erative design process where input values The risk of condensation should be pre- are optimised to meet both the comfort vented when using chilled ceiling sys- conditions as well as the optimum re- tems, because chilled panels and beams quirements of the product operation. are not equipped with either a drain tray or condensate evacuation. There are dif- The room control system is selected after ferent methods for condensation preven- the beam selection to ensure the selected tion, refer to the chapter 5.4 Prevention of indoor climate parameters and the energy Condensation. efficiency of system. After that the critical points of water and air distribution, the Additionally a dew-point alarm in high- chilled beam system operation is checked risk areas is recommended. The electronic as well as the management principles of dew-point alarm is equipped with a sen- the building management system.

SelectionSelection ofof thermalthermal environmentenvironment levellevel Determination of space design parameters • Room air temperature / summer q = 23…26 OOC • Room air temperature / summer qaa = 23…26 C • Room air temperature / winter q = 20…22 OOC • Room air temperature / winter qaa = 20…22 C

SelectionSelection ofof thethe indoorindoor airair qualityquality levellevel andand airair flowflow raterate • Fresh air flow requirement q = 1.5…3 l/s,m22 and/or 10…15 l/s,person • Fresh air flow requirement qpp = 1.5…3 l/s,m and/or 10…15 l/s,person •• Calculate Calculate infiltrationinfiltration throughthrough externalexternal wallwall basedbased onon pressurepressure // temperaturetemperature differencedifference • Select relative humidity level in the space R = 30…50% • Select relative humidity level in the space Rhh = 30…50% •• Primary Primary airair off-coiloff-coil temperaturetemperature • Temperate climate q =14…15 OOC (air moisture content 9…10 g/kg) • Temperate climate qpp = 14…15 C (air moisture content 9…10 g/kg) • Hot and humid climate q = 12…13 OOC (air moisture content 8…8,5 g/kg) • Hot and humid climate qpp = 12…13 C (air moisture content 8…8,5 g/kg) •• Check Check humidityhumidity balancebalance basedbased onon infiltration,infiltration, airair moisturemoisture contentcontent andand internalinternal loadsloads

CalculationCalculation ofof requiredrequired coolingcooling andand heatingheating capacitycapacity •• Heat Heat loads:loads: (dynamic(dynamic energyenergy simulationssimulations andand internalinternal loads):loads): PP << 80 80 (max(max 120)120) W/mW/m22 •• Heat Heat losseslosses PP << 45 45 W/mW/m22,floor,floor •• Check Check comfortcomfort conditionsconditions (draught(draught fromfrom windowswindows andand asymmetricasymmetric radiation)radiation) •• Cooling Cooling effecteffect ofof primaryprimary air:air: P =c· ρ ·q ·(q –q) = 1,005 kJ/(kg,K) · 1,20 kg/m33·q ·(q –q) Paa =cpp· ρww ·qpp ·(qpp –qaa) = 1,005 kJ/(kg,K) · 1,20 kg/m ·qpp ·(qpp –qaa)

AdjustmentAdjustment ofof buildingbuilding designdesign parametersparameters •• Decrease Decrease externalexternal loads/loads/ losseslosses byby betterbetter solarsolar shadingshading andand improvedimproved windowwindow typetype •• Improve Improve thethe windowwindow andand externalexternal wallwall structurestructure toto decreasedecrease infiltrationinfiltration

SelectionSelection ofof chilledchilled beambeam typetype •• active active beambeam (exposed(exposed oror integratedintegrated intointo ceiling)ceiling) •• passive passive beambeam ++ airair diffuserdiffuser (ceiling(ceiling // wallwall // floor)floor)

SelectionSelection ofof inletinlet waterwater temperaturetemperature(avoid(avoid condensation)condensation) • Temperate climate q = 14…16 OOC • Temperate climate qw1w1 = 14…16 C • Hot and humid climate q = 17…18 OOC • Hot and humid climate qw1w1 = 17…18 C

SelectionSelection ofof waterwater temperaturetemperature differencedifference and/orand/or waterwater flowflow raterate • Temperature difference Δθ = q -q = 2 - 4 °C • Temperature difference Δθww = qw2w2 -qw1w1 = 2 - 4 °C •• Water Water flowflow raterate (securing(securing turbulentturbulent flowflow insideinside thethe pipe)pipe) •q = 0.03…0.10 kg/s (15 mm pipe) •qww = 0.03…0.10 kg/s (15 mm pipe) •q = 0.02…0.08 kg/s (12 mm pipe) •qww = 0.02…0.08 kg/s (12 mm pipe) •q = 0.01…0.05 kg/s (10 mm pipe) •qww = 0.01…0.05 kg/s (10 mm pipe)

SelectSelect totaltotal andand activeactive lengthlength ofof beambeam • Specific cooling capacity of active beam P = 250 (max. 350) W/m • Specific cooling capacity of active beam PLL = 250 (max. 350) W/m • Specific heating capacity of active beam P = max. 150 W/m • Specific heating capacity of active beam PLL = max. 150 W/m •• Specific Specific primaryprimary airflowairflow raterate ofof activeactive beambeam 5…155…15 l/s,ml/s,m (dependent(dependent onon model)model)

NoiseNoise levellevel andand systemsystem pressurepressure lossloss calculationcalculation Selection of chilled beam type, length and design parameters

SelectionSelection ofof roomroom controlscontrols •• room room airair temperaturetemperature isis controlledcontrolled byby modulatingmodulating waterwater flowflow raterate •• two two portport valvesvalves withwith timetime proportionalproportional on-offon-off oror modularmodular controlcontrol •• constant constant airair flowflow raterate withwith possiblepossible standstand byby modemode whenwhen notnot occupiedoccupied

AirAir andand waterwater distributiondistribution systemsystem •• dehumidification dehumidification inin airair handlinghandling unitunit •• three three portport mixingmixing valvevalve inin coolingcooling pipepipe toto keepkeep thethe inletinlet waterwater temperature temperature inin designdesign valuevalue •• free free coolingcooling equipmentsequipments inin chillerchiller // airair handlinghandling unitunit

BuildingBuilding managementmanagement systemsystem (BMS)(BMS) •• dew dew pointpoint compensationcompensation ofof inletinlet waterwater temperaturetemperature (summer)(summer) •• outdoor outdoor temperaturetemperature compensationcompensation ofof inletinlet waterwater temperaturetemperature (winter)(winter) Design of room controls, water and air distribution systems and BMS

Figure 5.12 Design methodology of a chilled beam system.

6. PRODUCT SELECTION

PRACTICAL GUIDELINES − The cooling capacity of chilled beams is one of the major selection criteria. However other criteria also need to be considered such as linear cooling capacity and airflow rate, air velocity profile etc. − Technical data is comparable if it is measured using the same standards and presented using the same parameter values (e.g. reference air temperature and chamber pressure). − Use closed beams in suspended ceiling installations and exposed models in all other installation to avoid problems with wrongly directed throw pattern. − Pay attention also to accessories, ease of installation, and maintenance issues like cleanability of the coil and air plenum as well as access to the coil

There is large variety of chilled beams on the chilled beam, the dimensions and ge- the market, which makes the selection and ometry of the supply air slot as well as comparison between product types and the induction ratio of the chilled beam. manufacturers difficult. There are some

)

s 0 special technical details to be compared /

(

0.10 6 l/s,m when making chilled beam selection. 2 8 V 0.20 10 12 14 16 The cooling capacity of the chilled beam 0.30 18 20 22 is a major selection criterion. The techni- 0.40 24 cal data of different manufacturers are 46810 L2 (m) comparable if the cooling capacity meas- L B urements are made based on CEN stan- L L3 dards created for passive and active 1 chilled beams. This new standard is V V3 mainly following the existing Scandina- 1 0.5 m 2.7 m vian Nordtest (NT VVS 078) and German 1.8 m

DIN (4715) measurement standards. L2 0.1 m V2

The acoustic data should be based on Figure 6.1 Example of velocity data of active measurements according ISO standards chilled beam. Three critical points should be (EN-ISO 3741 and EN-ISO 5135) as well studied. Normally, velocity V2 is the most critical. as the airflow rate and pressure difference (EN-ISO 5167-1 and EN-ISO 5135). If there is a need to change a specified beam model during the contracting phase, It is also important to compare the veloc- it is important to compare beams in simi- ity data in the occupied zone created by lar design conditions e.g. using the same the active chilled beam. Each manufac- room air temperature (adequate cool- turer has a unit specific data for each ing/heating capacity), having the same chilled beam type, because the air veloci- linear cooling output and primary airflow ties are dependent on the construction of rate (risk of draught).

Also the architectural features vary between If chilled beams are connected to pipe different units. Some models can be used in work using flexible hoses, there are some exposed installation, but the capacity in the special requirements. Air diffusion resis- ceiling installation is reduced unless there tant hoses are recommended in order to are sufficient return air paths in the sus- avoid problems with oxygen in chilled pended ceiling. Respectively the beam water. It is also important that the pipe models developed for ceiling installation ends in chilled beam are circular to secure may create high velocities to the occupied a tight connection between hose and pipe. zone in free installation because they are unable to utilise the “coanda effect”.

Figure 6.2 There are two architecturally almost identical chilled beams. The chilled beam on the left does not perform well in exposed installation, whereas the throw pattern of the chilled beam on the right is directed correctly towards walls.

The types of materials used also vary between different manufacturers and models. Figure 6.3 Examples of chilled beam models The most critical for chilled beam opera- on the market. tion is the type of material used and the dimensions of the finned coil. The pipe CBC/B-100-3300-3000 size affects the waterside pressure drop. INPUT DATA Room air temperature Tr °C 24.0 The thickness of the fins affects the dura- Relative humidity of room air f % 50 Supply air flow rate qvs l/s 30.0 bility of coil during installation and main- Supply air temperature Ts °C 18.0 tenance (too thin fins bend more easily). Inlet water temperature Tw1 °C 15.0 Water flow rate qmw kg/s 0.060 Effective beam length l mm 3000 The fin pitch has an influence on heat Duct connection D mm 100 CALCULATED DATA 1 transfer and induction as well as the clean- Supply air capacity Pa W 215 ness of coil. Too small a fin pitch (≤ 3mm) Water capacity Pw W 769 Total capacity Pt W 984 collects more dust and is more difficult to Temperature difference dT °C 7.5 clean. The typical distance between fins is Outlet water temperature Tw2 °C 18.1 Sound pressure level (without damper) LpA dB 28 approximately 5 mm in active chilled Total pressure drop (without damper) dptot Pa 87 Pressure drop of water flow dpw kPa 4.0 beams and 9 mm in passive chilled beams. CALCULATED DATA 2 Dew point temperature of room air Tdew °C 12.9 Supply air flow rate/radiator length qv'a l/(sm) 10.0 In some models there is space inside the Supply air flow rate qvs l/s 30 beam for valve and damper installation. The Induced air flow rate qvi l/s 98 Air flow rate leaving the unit qvtot l/s 128 total length of the product is longer than the Temperature of air leaving the unit Ta °C 17.6 active length but the number of access doors Figure 6.4 Example of product selection of into ceiling void can be reduced. chilled beam.

A. TENDERING: Checklist B. CONTRACTING: Checklist 1. Capacity of chilled beam 1. Checking of drawings Cooling capacity per meter Number of beams Heating capacity per meter Installed cooling/heating capacity Supply airflow rate per meter Airflow rates Air chamber pressure Locations of beams Sound level Total / active length Mock-up test results Return air paths in the ceiling Test methods Obstacles in front of the chilled beam CEN Pipe and duct connections Nordtest / V-method Connections to lights, sprinkler, DIN speakers etc. ISO Other tests 2. Installations Slab system 2. Comfort requirements Suspended ceiling type Air temperature Plenum height Room air temperature Distance to walls Supply air temperature Temperature gradient in C. COMMISSIONING: checklist space Air velocity 1. Visual inspection Maximum velocity Colour and gloss Velocity in occupied zone Perforation for return air Draught rating Any protection / packaging left Surface temperatures Nozzle configuration Access to coil / valves / damper 3. Material Supply air slots direction? Casing design Surface finish Material thickness marks Surface treatment correct level Perforations Coil fin thickness and fin pitch 2. Inspection of plenum Dimensions of pipe and duct Free airflow at open beams connections Return air openings Thermal insulations of valves and 4. Installations pipes Suspended ceiling integration Pipe and duct connections Ceiling connections Flexible hose connections Hanging system Air vents Water and air connections Electric and other connections 3. Function Cooling / Heating capacity 5. Cleaning Airflow rate Access to coil Air velocity in occupied zone Removable bottom plate Inlet water temperature Access to air plenum Water flow rate Thermal comfort (ISO 7730) 6. Control system Sound level

7. INSTALLATION AND COMMISSIONING

PRACTICAL GUIDELINES − When installing chilled beams ensure that the main pipes are at a higher level than the beams and there are no air pockets in the pipe work.

− Fit the pipe coupling with extra care to avoid bending the pipes and breaking the heat exchanger’s welded joints. Beam pipes are small and relatively thin.

− Ensure that there is access to the water valves and dampers after installation. Remove the protective plastic covers from beam surfaces just before commissioning.

− If the balancing damper is too close upstream to the chilled beam, the airflow inside the beam may be disturbed and the air supply is adversely affected.

− Open all control and shut-off valves before filling the water pipes. Continuous venting is necessary during filling.

− Close the shut-off valves in each beam before flushing the main pipes to avoid blocking the control valves.

− Chamber pressure measurement is the most accurate method of measuring the primary airflow rate of active chilled beam.

7.1 Installation bottom to avoid collision of the supply air with the ceiling. Any other obstacles near Chilled beams can be installed fully ex- the beam should be low enough or far posed, recessed within a suspended ceil- enough away to make sure they are not ing or positioned above a perforated or an disturbing the air jet. open grid ceiling. For beams installed within or above a ceiling, suitable access The main pipes are installed first. Pipes must be provided for service and mainte- should be installed so, that they do not nance. leave any “air pockets”, and a venting valve should always be installed at the With an open type of chilled beam a free highest point of the vertical main pipes in area is required in the suspended ceiling the shaft. All extra joints are a leakage for re-circulation of room air. As a guide, risk. the minimum free area should be 30% of the beam front panel surface area. When a The direction of the supply air and water suspended ceiling is installed around an circuit connection directions must be se- open or a closed beam, it should be in the lected according to the beam orientation. same level or slightly higher than a beam The beam can be fixed directly onto the

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Chilled Beam Application Guidebook ceiling surface or hung with threaded 7.2 Flushing drop rods. The recommended positioning for the mounting bracket is about L/4 To minimize the dirt and facilitate flush- measured from the end of the beam. The ing, it is important to close open ends of weight of the beam (10–20 kg/m) must be pipes during the installation work. Before taken into account when beam installation starting the flushing it is important to and logistics in building site are planned. close the shut-off valves of individual beams and flush the main pipes first. Beams can be connected to the main pipes either by using crimp, screw or sol- 7.3 Filling-up and venting the der connection, or with flexible hoses. system The use air diffusion resistant hoses is recommended to prevent air from diffus- To ensure easy venting, care should be ing into the water pipe. When beams are taken that the main pipes are installed at a connected to the pipe, extra attention higher level than the beams. The horizon- should be paid to attaching the pipe cou- tal pipes should be installed, rising pling when using a spanner. The pipe slightly towards the venting points and wall is relatively thin and the whole pipe there should be no high points to create might bend and break the heat exchanger “air pockets” to the system. joints. Coupling rings should be used during the installation. Before filling up, all shut-off and control valves must be in the fully open position. The airflow balancing dampers are often The pumps should not be running during installed just before the active beam. It is the filling-up (static filling). Continuous important to have a sufficient safety dis- venting is necessary and it is recom- tance between the damper and the beam, mended to have both manual and auto- in order to avoid any disturbance of the matic venting systems installed. The beam operation. If the iris damper is situ- pump should only be started when filling ated too close to the straight connected is complete. To remove all air from the beam, there is a risk that the first nozzles system, the major part (>75%) of the sys- will suck air into the plenum instead of tem should be closed so that the water can blowing it out, thus creating a noise prob- circulate fast enough. When each section lem. is full, it should be closed, and the same procedure repeated for the rest of the sys- Chilled beams are often supplied with tem. factory installed protective covers to both the heat exchanger and the inlet to the 7.4 Commissioning supply air plenum. Protective end caps should also be fitted to the heat exchanger The required air and water flow rates are pipes. These must be removed during the adjusted during commissioning. The air- installation. Plastic film protecting sheet flow rates are typically adjusted with a metal surfaces should be removed just blade or an iris damper. before commissioning.

The iris damper should be positioned far balancing valves and ensuring that all the enough away from the beam to ensure the shut-off valves are open. The chilled even flow inside the duct before a beam. beam water flow rate is controlled by a This safety distance (>3D) is needed to control valve; which is typically an on-off avoid any performance failure. or modulating valve. Balancing valves can be replaced with control valves with Measuring the airflow rate by using a adjustable kv-value. chamber pressure measurement in the beam is recommended. This gives the Check the function with an IR-sensor di- most accurate measurement result due to rected towards the chilled beam supply the higher pressure level (50−150Pa). In air slot after maximum cooling capacity is other methods e.g. pitot-tube measure- set on the room controller. Temporarily ment the pressure level is much lower. lowering the chilled water set point to approximately 10°C during commission- The commissioning of the chilled and hot ing will highlight any malfunction of sys- water circulation systems is carried out tem (too low water flow rate, shut off by balancing the water flow rates using valves closed, etc.).

Figure 7.1 Connection of chilled water pipes after installing the beam in the ceiling.

Figure 7.2 Installation of an active chilled beam using flexible hoses in the water pipes and flexible duct in air side.

8. RUNNING OF CHILLED BEAM SYSTEM

8.1 Maintenance and adheres more easily to the wet surface of Replacement fins. When the coil is dry again the fin surface is often coated with dirt. When The chilled beam system operation is sim- the coil is dry, the dust particles coming ple and trouble-free, with limited mainte- from the secondary air are so small that nance requirements. Although the mainte- they pass through the finned coil. The air nance of the beam system is minimal it is velocity through the coil is approximately important to have easy access to the inside 0.1 – 0.2 m/s. of the beam without disturbing the suspended ceiling. Access doors should allow There are no moving parts apart from the access to the heat exchanger, supply air control valve, so there are only minor re- plenum and primary air ductwork for placements needed during the life cycle. cleaning, service and maintenance. Beam systems do not include filters or condensation collection drains and pipes The heat exchanger should be vacuum which require cleaning. cleaned once every 1−5 years depending on the use of space. The more dust gener- 8.2 Essential Issues in Beam ated during use, the more often the need Operation for cleaning. It is important to train the operating per- However, if for some reason either the sonnel to manage the beam system cor- beam surface or the finned coil becomes rectly, especially when they have previ- wet, it must be cleaned immediately. Dirt ously been running wet systems.

Figure 8.1 Cleaning of chilled beam.

The following items are essential in beam The solutions for typical complaints of operation: end users are: Draught The chilled beam system is a dry- Firstly, check that the room air cooling system and therefore the inlet temperature is not too low. water temperature must always be Secondly, check that the airflow rate is above the dew point temperature. not too high or too low. Too high an When condensation occurs, the water airflow rate may create draught near the circulation in that area must be stopped, floor. Whereas, if the airflow rate is too even before looking for the cause of the low or too cold, the air jet may fall condensation. intentionally downwards, which may If the room air has become too humid, create draught at the neck level. the ventilation should be switched on, High room air temperature and after the building has been Check that water flow rate is not too low dehumidified, the water circulation can Check that the water flow temperature be restarted. is not too high It is important that the dehumidification If the heat loads in the space are by the air-handling unit has been significantly higher than the capacity of realised correctly and that the control the chilled beam the water flow rate operates properly. could be increased. If this does not The operation of the 3-way mixing solve the problem, longer or additional valve should be checked regularly. units should be installed.

Figure 8.2 When the chilled beam system is well designed, installed and commissioned, and the maintenance of the system is continuous, the chilled beam system provides an excellent and pro- ductive working environment.

9. CASE STUDIES

9.1 A Case of Office Building in United Kingdom

Project Office Building in London Room Lay-out and Measurement Grid: Space, where chilled Office room beams are used Window internal 30°C surface temperature Sensible internal 50 W/ m²,floor heat loads External heat loads 30 W/ m²,floor Heat losses 25 W/ m²,floor Supply air properties 2.5l/s,floor-m², supply air temperature in summer 16°C and winter 18°C Room design Room air temperature in BULKHEAD "A" BEAM INTERMEDIATE "B" BEAM PERIMETER BEAM parameters summer 24°C and winter Simulation window 21°C Flexibility Flexibility of 2.65 m, beams installed lengthwise in every module BULKHEAD "A" BEAM INTERMEDIATE "B" BEAM PERIMETER BEAM

Viewing window

Chilled beam Exposed, open active service chilled beam, total length 5100 mm, effective length 4200 mm, cooling output selection 370W/m, heating output 120W/m, primary air volume 11l/s,m, cooling water flow rate 0.04kg/s and inlet water temperature of 14°C, heating water flow rate 0.01kg/s and inlet water temperature of 35°C

Measurement result: cooling 10 8 6 4 2 Height v T a Turb. DR v Ta Turb. DR v Ta Turb. DR v Ta Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) 1.80 0.11 22.6 40 9 0.11 22.9 46 10 0.10 22.9 45 8 0.11 23.1 58 10 0.07 23.2 46 4 1.50 0.12 22.4 35 10 0.10 22.8 45 8 0.11 22.8 40 9 0.12 23.0 49 11 0.09 23.1 39 7 1.10 0.10 22.3 31 8 0.10 22.6 43 8 0.09 22.8 45 7 0.14 22.8 45 14 0.11 23.1 39 9 0.60 0.07 22.3 46 4 0.09 22.5 46 7 0.08 22.8 50 6 0.13 22.9 36 11 0.11 23.1 51 10 0.20 0.09 22.2 42 7 0.11 22.4 46 10 0.06 22.8 45 3 0.10 23.0 44 8 0.10 23.1 49 8 0.10 0.15 22.1 31 14 0.16 22.2 33 15 0.09 22.7 40 7 0.11 23.0 40 9 0.13 23.1 43 12

Measurement result: heating 10 8 6 4 2 Height v T a Turb. DR v Ta Turb. DR v Ta Turb. DR v Ta Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) (%) (m/s)(°C) (%)(%) (m/s) (°C) (%) (%) (m/s) (°C) (%)(%) (m/s) (°C) (%) (%) 1.80 0.04 21.7 52 - 0.08 21.7 33 6 0.08 21.7 42 6 0.08 21.4 35 6 0.07 21.2 44 5 1.50 0.03 21.5 50 - 0.07 21.5 52 5 0.08 21.5 44 6 0.09 21.4 41 8 0.08 21.2 39 6 1.10 0.03 21.2 46 - 0.04 21.2 79 - 0.03 21.2 43 - 0.10 21.3 34 9 0.08 21.2 34 6 0.60 0.02 20.6 32 - 0.02 20.6 27 - 0.02 20.6 33 - 0.06 20.8 53 3 0.07 20.9 59 5 0.20 0.02 20.4 30 - 0.02 20.3 20 - 0.03 20.2 36 - 0.06 20.2 40 3 0.11 20.5 37 11 0.10 0.02 20.3 28 - 0.02 20.1 28 - 0.03 19.9 35 - 0.05 19.6 32 - 0.09 19.9 34 8

9.2 A case of Office Building in France

Project Office Building in Paris Room Lay-out and Measurement Grid: Space, where chilled Office room beams are used Window internal 30°C surface temperature Sensible internal heat 45 W/m²,floor loads External heat loads 40 W/ m²,floor Heat losses 50 W/ m²,floor Supply air properties 2 l/s,floor-m², supply air temperature in summer 14°C and winter 21°C Room design Room air temperature in parameters summer 24°C and winter 21°C 1 2 3 4 5 Flexibility Flexibility of 1.5 m, beams installed lengthwise in every second module

Chilled beam 600 mm wide, closed active chilled beam, total length 3000 mm, effective length 2700 mm, cooling output selection 400 W/m, heating output 270 W/m, primary air volume 9 l/s,m, cooling water flow rate 0.10 kg/s and inlet water temperature of 14°C, heating water flow rate 0.013 kg/s and inlet water temperature of 40°C

Measurement result: cooling with standard air diffusion. 1 2 3 4 5 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s)(°C) (%) (%) (m/s) (°C) (%) (%) 1.80 0.05 23.7 47 - 0.05 23.8 45 - 0.08 23.8 73 6 0.06 23.6 56 3 0.51 21.5 10 39 1.40 0.05 23.6 46 - 0.06 23.6 51 3 0.07 23.5 48 4 0.08 23.5 45 5 0.49 21.5 11 39 1.10 0.05 23.5 53 - 0.06 23.4 60 3 0.08 23.4 47 5 0.09 23.8 43 6 0.41 21.6 16 37 0.60 0.07 23.4 53 4 0.10 23.4 44 8 0.11 23.4 39 9 0.06 23.3 46 3 0.28 22.3 38 33 0.20 0.13 23.4 25 10 0.10 23.5 46 8 0.07 23.5 39 4 0.17 22.8 29 15 0.16 22.6 35 15 0.10 0.16 23.3 23 12 0.13 23.6 43 11 0.10 23.4 33 7 0.13 22.8 38 12 0.16 22.6 36 15

Measurement result: cooling with reduced induction in the right hand side of a beam (cooling capacity is reduced 11%) 1 2 3 4 5 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s)(°C) (%) (%) (m/s) (°C) (%) (%) 1.80 - 0.09 23.6 42 6 0.07 23.7 59 4 0.11 23.8 44 9 0.11 23.6 57 10 1.40 - 0.06 23.6 48 3 0.06 23.6 48 3 0.08 23.6 49 5 0.10 23.5 47 8 1.10 - 0.06 23.5 52 3 0.08 23.4 44 5 0.08 23.4 58 6 0.11 23.4 41 9 0.60 - 0.07 23.5 45 4 0.08 23.4 38 5 0.13 23.3 39 11 0.13 2.5 28 30 0.20 - 0.06 23.5 47 3 0.08 23.5 42 5 0.15 23.3 23 11 0.08 23.7 35 5 0.10 - 0.12 23.5 35 9 0.09 23.5 47 7 0.16 23.3 30 13 0.10 23.6 32 7

Measurement result: heating 1 2 3 4 5 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s) (°C) (%) (%) (m/s)(°C) (%) (%) (m/s) (°C) (%) (%) 1.80 0.40 22.3 11 29 0.10 22.0 37 8 0.09 21.4 54 8 0.09 21.8 31 7 0.13 22.3 31 11 1.40 0.23 21.4 46 31 0.12 21.7 30 11 0.04 20.7 53 - 0.05 20.9 33 - 0.07 22.0 45 5 1.10 0.10 20.1 56 11 0.05 19.8 46 - 0.03 19.7 39 - 0.03 20.0 59 - 0.03 19.8 36 - 0.60 0.03 18.8 22 - 0.03 18.8 34 - 0.02 18.7 46 - 0.02 18.9 23 - 0.02 18.5 24 - 0.20 0.05 18.4 24 - 0.05 18.0 27 - 0.03 18.0 36 - 0.02 18.3 31 - 0.02 18.0 35 - 0.10 0.04 18.2 29 - 0.06 17.6 20 3 0.04 17.6 28 - 0.03 17.9 33 - 0.02 17.5 26 -

9.3 A case of Office Building in Sweden

Project Office Building in Stockholm Room Lay-out and Measurement Grid: Space, where chilled Office room / meeting room with extra supply air beams are used diffuser Window internal 31.5°C surface temperature Sensible internal heat 25 W/m²,floor loads External heat loads 40 W/m²,floor Supply air properties 1.5 / 3.8 l/s,floor-m², supply air temperature in summer 16°C Room design Room air temperature in summer 23°C parameters 11 12 13 14 Flexibility Flexibility of 1.1 m, beams installed lengthwise in

every second module 8 9 10 Chilled beam selection 600 mm wide, closed active chilled beam, total length 3000 mm, effective length 2700 mm, cooling output 240 W/m, primary air volume 6 l/s,m, cooling water flow rate 0.09 kg/s and inlet water temperature of 15°C, additional perforated diffuser in meeting room application

Measurement result: office space 11 12 13 14 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % 1.80 0.04 23.2 57 - 0.04 23.1 55 - 0.02 23.2 52 - 0.09 23.3 39 6 1.50 0.06 23.1 43 3 0.07 23.0 53 4 0.05 23.1 38 - 0.08 23.2 39 5 1.10 0.07 23.1 24 4 0.10 22.9 41 8 0.06 23.0 36 2 0.08 23.2 39 5 0.80 0.08 23.1 35 5 0.10 22.9 34 8 0.09 23.0 29 6 0.08 23.2 35 5 0.50 0.06 23.1 35 2 0.10 22.9 38 8 0.07 23.0 37 4 0.06 23.2 26 2 0.10 0.06 23.1 43 3 0.08 23.3 37 5 0.05 23.5 35 - 0.08 23.5 49 5 8 9 10 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % 1.80 0.06 23.0 38 3 0.09 23.1 33 6 0.07 23.3 33 4 1.50 0.05 22.9 38 - 0.08 23.1 49 6 0.08 23.1 30 5 1.10 0.05 22.9 44 - 0.12 23.1 39 10 0.08 23.1 32 5 0.80 0.05 22.8 35 - 0.12 23.0 36 10 0.06 23.1 33 2 0.50 0.05 22.8 52 - 0.15 22.6 28 13 0.05 23.0 47 - 0.10 0.10 22.9 29 7 0.11 22.8 37 9 0.14 22.8 27 11

Measurement result: meeting room 11 12 13 14 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % 1.80 0.09 23.2 56 7 0.06 23.2 59 3 0.08 23.4 52 6 0.07 23.3 53 4 1.50 0.09 23.0 46 7 0.10 23.1 41 8 0.10 23.2 51 8 0.06 23.3 64 3 1.10 0.09 23.0 43 7 0.12 23.1 34 10 0.08 23.1 42 5 0.06 23.2 47 3 0.80 0.09 23.0 37 7 0.14 23.2 34 12 0.10 23.0 23 7 0.06 23.2 44 3 0.50 0.06 23.1 42 3 0.12 23.3 33 9 0.10 23.1 28 7 0.04 23.2 51 - 0.10 0.07 23.4 38 4 0.08 23.8 37 5 0.10 23.9 42 7 0.17 23.4 27 14 8 9 10 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % 1.80 0.05 23.1 52 - 0.09 23.2 31 6 0.08 23.3 35 5 1.50 0.05 23.0 48 - 0.08 23.1 45 6 0.06 23.2 37 2 1.10 0.06 22.9 58 3 0.08 23.2 51 6 0.06 23.3 43 3 0.80 0.07 22.7 57 5 0.09 23.0 46 7 0.05 23.3 42 - 0.50 0.08 22.8 57 6 0.10 22.7 41 8 0.05 23.1 54 - 0.10 0.14 23.5 28 11 0.10 23.0 29 7 0.13 22.9 34 11

9.4 A Case of Office Building in Belgium with High Performance Values

Project Office Building in Belgium Room Lay-out and Measurement Grid: Space, where chilled Office room beams are used Window internal 38°C surface temperature Sensible internal heat 35 W/m²,floor loads External heat loads 65 W/m²,floor Heat losses 80 W/ m²,floor Supply air properties 3 l/s,floor-m², supply air temperature in summer 15°C and winter 15°C Room design Room air temperature in parameters summer 25°C and winter 21°C, relative humidity in summer under 50%, Flexibility Flexibility of 1.5m, beams installed 6 5 4 3 2 1 crosswise in every module

Chilled beam 300mm wide, open active chilled beam, total length 1400mm, effective length 1200mm, cooling selection output 500 W/m, heating output 380W/m, primary air volume 15l/s,m, cooling water flow rate 0.10kg/s and inlet water temperature of 15°C, heating water flow rate 0.038kg/s and inlet water temperature of 55°C

Measurement result: cooling 1 2 3 4 5 6 Height v T a Turb. DR v Ta Turb. DR v Ta Turb. DR v Ta Turb. DR v Ta Turb. DR v T a Turb. DR (m/s) (%) % (m/s) (%) % (m/s) (%) % (m/s) (%) % (m/s) (%) % (m/s) (%) % (m) (°C) (°C) (°C) (°C) (°C) (°C) 2.00 0.34 24.2 25 29 0.10 24.7 34 6 0.13 24.8 24 8 0.13 25.0 31 9 0.18 25.0 42 15 0.08 25.7 45 4 1.70 0.25 24.3 36 23 0.09 24.6 29 5 0.13 24.7 35 9 0.12 24.9 33 8 0.16 25.1 35 12 0.09 25.6 54 6 1.40 0.20 24.4 37 17 0.06 24.5 52 2 0.08 24.6 52 5 0.11 24.9 31 7 0.15 25.2 42 12 0.09 25.6 52 6 1.10 0.15 24.4 45 13 0.07 24.5 67 4 0.07 24.5 57 4 0.10 24.8 45 7 0.12 25.1 48 9 0.09 25.4 66 6 0.60 0.08 24.5 59 5 0.14 24.4 41 11 0.11 24.5 49 9 0.08 24.9 41 5 0.13 25.1 43 10 0.09 25.2 58 6 0.10 0.22 24.3 20 15 0.25 24.3 21 18 0.11 24.6 54 9 0.04 25.3 59 - 0.08 25.1 35 4 0.11 25.1 54 8

Measurement result: heating 1 2 3 4 5 Height v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR v T a Turb. DR (m) (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % (m/s) (°C) (%) % 2.00 0.15 22.8 28 13 0.07 22.6 45 4 0.07 22.6 48 4 0.03 22.7 44 - 0.06 22.3 48 3 1.70 0.09 22.5 42 7 0.05 22.4 58 - 0.03 22.2 42 - 0.03 22.2 41 - 0.05 22.0 47 - 1.40 0.12 22.4 44 11 0.04 22.2 34 - 0.02 21.9 36 - 0.02 21.8 30 - 0.03 21.8 34 - 1.10 0.12 21.9 37 11 0.04 21.6 32 - 0.02 21.5 39 - 0.02 21.5 25 - 0.04 21.4 30 - 0.60 0.04 21.1 18 - 0.03 20.9 23 - 0.03 21.0 19 - 0.03 21.1 25 - 0.02 21.0 19 - 0.10 0.03 20.6 19 - 0.02 20.5 29 - 0.02 20.5 16 - 0.02 20.2 24 - 0.03 20.1 35 -

9.5 A Case of Office Building in Finland with Passive Chilled Beams

Project Office Building in Helsinki Room Lay-out and Measurement Grid: Space, where chilled Office room beams are used Window internal 26.5°C surface temperature Sensible internal heat 35 W/m²,floor loads External heat loads 15 W/m²,floor Supply air properties 2 l/s,floor-m², supply air temperature in summer 18°C Room design Room air temperature in summer 26°C parameters Flexibility Flexibility of 2.8 m, beams installed crosswise above door Chilled beam selection 300 mm wide, passive chilled beam, total length 2400 mm, effective length 2200 mm, cooling output 190 W/m, cooling water flow rate 0.03 kg/s and inlet water temperature of 15°C

Measurement result: cooling 1 8

Height v T a Turb. D R v T a Turb. DR (m) (m /s) (°C) (%) % (m /s) (°C) (% ) % 1.80 0.05 26.0 63 0 0.10 26.1 19 5 1.50 0.06 26.1 51 2 0.02 26.4 31 - 1.10 0.09 25.9 37 5 0.12 26.1 19 6 0.80 0.12 25.8 25 6 0.12 26.2 24 6 0.50 0.09 25.7 33 5 0.08 25.6 42 4

2 5 9

Height v T a Turb. D R v T a Turb. D R v T a Turb. DR (m) (m /s) (°C) (%) % (m /s) (°C) (%) % (m /s) (°C) (% ) % 1.80 0.07 26.2 49 3 0.14 26.1 26 8 0.11 26.0 28 6 1.50 0.10 26.2 45 6 0.10 26.3 22 5 0.08 26.3 45 4 1.10 0.15 25.9 23 8 0.09 26.1 19 4 0.05 26.0 51 - 0.80 0.15 25.7 25 9 0.07 26.2 28 3 0.08 26.1 41 4 0.50 0.24 25.4 19 15 0.14 25.5 24 8 0.12 25.7 21 7

3 6 10

Heigh v T a Turb. D R v T a Turb. D R v T a Turb. DR (m) (m /s) (°C) (%) % (m /s) (°C) (%) % (m /s) (°C) (% ) % 1.80 0.07 26.1 50 3 0.06 26.3 36 2 0.13 26.0 31 7 1.50 0.09 26.1 37 5 0.05 26.4 33 - 0.07 26.3 60 3 1.10 0.09 25.8 42 5 0.05 26.1 44 - 0.08 26.0 36 4 0.80 0.11 25.6 36 7 0.05 26.2 42 - 0.11 26.0 40 6 0.50 0.26 25.1 21 18 0.12 25.3 26 7 0.17 25.5 16 10

4 7 11

Heigh v T a Turb. D R v T a Turb. D R v T a Turb. DR o o o t (m) (m /s) ( C) (%) % (m /s) ( C) (%) % (m /s) ( C) (% ) % 1.80 0.07 26.0 40 2 0.05 25.9 36 - 0.17 25.9 23 10 1.50 0.04 26.2 46 - 0.03 26.1 62 - 0.12 26.0 32 7 1.10 0.06 25.8 39 2 0.07 25.8 53 3 0.08 25.8 47 5 0.80 0.08 25.6 34 4 0.11 25.9 69 8 0.06 26.0 50 2 0.50 0.23 24.8 21 16 0.27 25.0 16 16 0.19 25.5 14 11

10. REFERENCES

[1] ISSO (2001), Climatic Ceilings and Chilled Beams; Applications of Low Temperature heating and High Temperature Cooling, Thermic Project no. DIS/1522/97/FR, New solutions in Energy Utilisation, European Commission

[2] ISSO (2001), Climatic Ceilings; Technical Note: Design Calculations, New solutions in Energy Utilisation, European Commission

[3] CEN Report 1752; Ventilation for Buildings – Design criteria for the indoor environment

[4] Directive of the European Parliament and of the Council on the energy performance of the buildings

[5] Halton Oy, Cooled Beam System, Design Guide, 2000

[6] Laine T, Kosonen R, Horttanainen, P, Laitinen A. LCC comparison of air-conditioning systems. Indoor Air 99. Edinbugh, Scotland 8-13.8. 1999. The 8th International Conference on Indoor Air Quality and Climate. pp. 602-603

[7] Butler D, Swainson M. Perimeter Chilled Beams BRE Information Paper IP 11/04 September 2004. BRE, Watford, UL.

[8] Stifab Farex system guide

[10] Skanska Internal Case Studies

[11] Halton Oy laboratory measurement reports

[12] EN 14518 Ventilation for buildings - Chilled beams - Testing and rating of passive chilled beams

[13] prEN 15116 Ventilation in buildings - Chilled beams - Testing and rating of active chilled beams

[14] Kosonen R, Tan F. A Feasibility Study of a Ventilated Beam System in the Hot and Humid Climate: A Case-Study Approach. 2003 (not published).

[15] ASHRAE. Pocket Guide for Air Conditioning, Heating, ventilation and Refrigeration (SI units) American Society of Heating, Refrigerating and Air-Conditioning Engineers, INC, Atlanta, GA, USA 1997.

[16] Fanger PO. Thermal comfort, McGraw-Hill Book Company 1972.

[17] Kosonen, R., Horttanainen, P, Dunlop, G. Integration of heating mode into ventilated cooled beam. Proceedings of Roomvent 2000.

Single user license only, copying and networking prohibited. All rights reserved by REHVA. REHVA Guidebooks: No 1 Displacement Ventilation in Non-industrial Premises No 2 Ventilation Effectiveness No 3 Electrostatic Precipitators for Industrial Applications No 4 Ventilation and Smoking No 5 Chilled Beam Cooling No 6 Indoor Climate and Productivity in Offices No 7 Low Temperature Heating And High Temperature Cooling No 8 Cleanliness of Ventilation Systems No 9 Hygiene Requirement for Ventilation and Air-conditioning No 10 Computational Fluid Dynamics in Ventilation Design No 11 Air Filtration in HVAC Systems No 12 Solar Shading – How to integrate solar shading in sustainable buildings No 13 Indoor Environment and Energy Efficiency in Schools – Part 1 Principles No 14 Indoor Climate Quality Assessment No 15 Energy Efficient Heating and Ventilation of Large Halls

REHVA Reports: No 1 REHVA Workshops at Clima 2005 - Lausanne No 2 REHVA Workshops at Clima 2007 - Helsinki No 3 REHVA Workshops at Clima 2010 - Antalya rehva Federation of European Heating, Ventilation and Air-conditioning Associations

REHVA Office Washington Street 40, 1050 Brussels – Belgium Tel: +32-2-5141171 Fax: +32-2-5129062 Orders: www.rehva.eu [email protected]