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P LU M B I N G & H E AT I N G SOLUTIONS U N D E R F LO O R H E AT I N G W I T H G R O U N D S O U R C E H E AT P U M P S

A guide to using with Ground Source Heat Pumps Introduction

There is increasing interest in these environmentally friendly systems due to the potential for low running costs, reduction in use of fossil fuels, and the reduction in CO2 emissions. It is not the intention to discuss the individual features and benefits of Under Floor Heating (UFH) and Ground Source Heat Pumps (GSHPs), however, this document is intended to give the User, Installer and Specifier some useful points for selecting and designing an UFH system to gain the maximum benefits from a GSHP installation. This document will be useful for those who have already decided to use this type of system and are keen to understand how they maximise the benefits of the synergy between two proven technologies.

2  Energy Efficiency of the System

A GSHP is designed to extract Electrical Input from the ground and convert this to useful energy, which 1 kW can be used for heating and also 4 kW hot generation within the building. It uses electricity to run 3 kW the and to pump a mix Output from Free Energy from the of water and food grade Ground solution around the primary ground loop pipe work. Fig 1 : Typical Energy Balance Diagram for GSHP

A well-designed system will be • Insulation of the building fabric of air from outside. capable of transferring 4kW of • Air tightness of the building Buildings should be designed useful into the with energy conversation in mind, • Whether a heat recovery and building for every 1kW unit of air tight and with a high level of ventilation (HRV) system is electricity consumed by extracting . Because of employed 3kW of free solar energy transferred the high capital costs a GSHP is • Temperature of water/ from the outside ground. The sometimes sized to handle part antifreeze solution in the efficiency of a heat pump is given of the total design load, with the ground loop(s) by its Coefficient of Performance balance usually made up by an • Design water temperature for auxiliary electric heater. A GSHP (COP), which is simply the thermal the underfloor heating sized at 50% of the design load is output divided by the electricity likely to meet at least 80% of the consumed, i.e. in the example • Structure and thermal mass of the underfloor annual heating requirements, while above: 4kW/1kW = COP of 4. a unit sized at 75% will meet the • Floor covering resistances Or in other words, the GSHP is heating requirement most of the • Control system 400% efficient by producing 4 time, apart from times of very cold times the amount of thermal An accurate assessment of the weather. energy from one unit of electricity building heat loss is very important - although this disregards the when sizing a GSHP. The two efficiency of electricity generation components of building heat loss are: 1) the thermal losses through at the power station. To achieve an the building fabric and 2) the level efficient COP of about 4 requires careful consideration of a number of practical issues, such as:

 Key Factors

Insulation of the Building Fabric rooms within the property. The 3) Water flow rate and design The insulation level within the systems enable better control of air temperature difference building is a fundamental factor in infiltration rate and provide heat – systems should be designed the suitability of a GSHP system. exchange efficiencies of around with 5oC temperature A high level of thermal insulation 90% in converting heat from the difference; will produce low building heat extracted air to the incoming 4) The – room losses. A low heat loss means that fresh air. Heat energy is recovered temperature set-points of 20oC the UFH system can run on lower therefore reducing the load on the or less is preferred; water temperatures, which in-turn GSHP and enabling the UFH to leads to a higher COP for the GSHP. run at lower water temperatures, 5) Thermal resistance of floor It is of utmost importance that which in-turn improves the system covering(s) - low thermal good quality insulation has been efficiency. resistance coverings are specified and that the building desirable, e.g. tiles, slate, Temperature of the solution in is well insulated throughout. The marble etc; the ground loops insulation within the ground floor Higher COP’s will be achieved 6) The room heat losses – ultra is of particular importance when when the difference between insulated buildings will gain the UFH is installed, as increased floor primary side and secondary side most benefit. temperature will result in higher temperatures are small; primary side downward losses when compared Structure and thermal mass being the entering temperature to a system. For this reason Solid screed or floors of the water/antifreeze solution - and especially if floor coverings offer the best solution for floor into the GSHP, while secondary have fairly high thermal resistance, structure and, ideally, should be side being the outlet temperature such as carpet or wooden floors used for both ground and upper to the UFH system. So a relative - ground floor insulation should be floors. Other systems such as high temperature of the water/ supplemented in excess of Building timber suspended, with aluminium antifreeze solution in the ground Regulation requirements to reduce heat emission plates or a reflective loop system is beneficial; usually downward losses to less than 10 foil (Unifoil), should only be used GSHP systems will run on entering W/m2. when heat requirements are so low temperatures ranging between -5oC as to allow them to satisfactorily Air tightness of the building to +12oC. The design and type of operate well below the 50oC – 55oC The building air tightness is a major GSHP and ground loop will need to mean water temperature normally component of the overall building be discussed and agreed with the required. The same applies to heat loss. Uncontrolled infiltration GSHP supplier. floating floor systems, which consist of external air can result in relatively Design water temperature for of a heat emission plates sitting high heat losses during the winter the UFH above insulation and usually a period. Rooms with open fires, Higher energy efficiencies will result chipboard floated deck. Although where air change rates can reach 5 with UFH operating below 45oC floating floors have the option of per hour, should be avoided. It is water flow temperature; the lower being installed with a dry screed recommended that an air leakage the better. Factors determining the system (e.g. Fermacell or similar pressure test should be carried design water temperature for an boards), as opposed to chipboard, out to verify that the design air UFH system include: which would result in required water infiltration rates are met. temperatures approaching that of a 1) The floor structure and type of Heat recovery and ventilation solid screed/concrete floor. UFH system installed - pipes These systems are designed to embedded within screed/ Careful consideration should be remove warm air from certain concrete floors is best; given to UFH systems of mixed rooms within the building, such as construction, as different water kitchen and bathroom areas, extract 2) The pipe spacing and pipe size temperatures may be required, even it through a to – larger pipes installed at tight in ultra low energy buildings. pre-heat outside air, and to supply pipe centres is best; this tempered fresh air to other

 A system with pipes embedded Floor covering thermal in a 75mm screed would give the resistance system thermal mass; heat transfers UFH will work with most types of The table below shows a graphical from the water in the UFH pipes floor coverings. However, it should representation of floor heat outputs and slowly warms up the screed, be understood that coverings with for different floor structures and some of the heat is retained in the relatively high thermal resistances various floor covering resistances. screed while some is gently released will need to increase the UFH water to warm the room. This degree of temperature to offset building heat thermal inertia allows the possibility losses, and will result in a lower COP of utilising cheap rate electricity to and therefore higher running costs. charge the floor overnight to give a proportion of the heat output needed during the following day.

Fig. 2 – Table showing floor output at various mean water temperatures

 Floor Constructions & Thermal Resistance

Solid Floor Screed or concrete floor with 15mm pipes spaced at 200mm centres. Where R = thermal resistance of the floor covering [m2K/W]. R = 0.00, typically: tiles, slate, marble or stone. R = 0.05, typically: vinyl or thin laminate. R = 0.10, typically: carpet or laminate. R = 0.15, typically: heavier tog carpet or solid wood floor.

Heat Emission Plates Timber suspended or floating floor with 15mm pipes spaced at 200mm centres and heat emission plates (HEP’s) effectively covering 85% of the floor area. Where R = thermal resistance of floor covering on top of 18mm chipboard deck [m2K/W]. R = 0.00, typically: tiles R = 0.10, typically: carpet or laminate. R = 0.20, typically: heavier tog carpet or solid wood floor.

Unifoil Timber suspended with 15mm pipes spaced at 200mm centres fixed in 50mm void above Unifoil highly reflective material. Where R = thermal resistance of floor covering on top of 18mm chipboard deck [m2K/W]. R = 0.00, typically: tiles R = 0.10, typically: carpet or laminate. R = 0.20, typically: heavier tog carpet or solid wood floor.

Coefficient of Performance (COP) Figure 3 (right) shows the importance of the UFH water temperature in determining the operating COP of the GSHP. The output temperature is the flow temperature of the UFH system. Some GSHP manufacturer’s preset their unit to run with an UFH return temperature of 30oC, which with a 5oC temperature difference equates to a 35oC flow temperature. However, it can be seen from figure 2 that 35oC flow temperature would usually suit solid Fig. 3 – Coefficient of Performance (COP) graph for floor constructions only, unless the heat typical GSHP’s requirement dropped below 40 W/m2; an unlikely scenario in all but the ultra low energy buildings.

 Controls, Thermal Storage and Radiant Cooling

Control System hot water via the GSHP will Summary During the heating season the reduce efficiency because output GSHP’s are considered to be outside temperature remains temperature required is higher than energy efficient appliances and above design conditions for the for UFH. If the system incorporates ideally should be coupled with heat majority of the time, which means hot water storage then time control emitters operating at the lowest the system needs only cater for to maximise the use of cheaper possible water temperature to gain part load conditions during these tariff electricity is recommended. optimum benefits. UFH is the best periods. A weather compensator choice of heat emitter as it has a Cheap rate electricity controller is usually incorporated large surface area, with a relatively Details of economy 7, economy into the GSHP and this will vary low floor surface temperature, 10, and in some areas special the water temperature to the UFH and therefore a low circulating GSHP tariff, should be checked based on the temperature outside. water temperature is required. This out with your electricity supplier. During mild weather the GSHP will document clearly shows that floor Your GSHP provider may suggest or be operating on a lower UFH water construction, floor covering thermal provide energy storage equipment, temperature, which will meet the resistance, and building heat losses in addition to the GSHP, to make lower building heat loss and result are main factors in determining the most use of cheap rate tariffs. in higher system energy efficiency, the water temperature for the UFH sources can COP. system. And that floor constructions also be used, such as: solar panels other than screed/concrete Because room heat losses do not (photovoltaic) and wind turbines. should be used with considerable always change solely in proportion Radiant Cooling caution, even with modern well- to the outside air temperature Some GSHP’s have a cooling insulated buildings. Also shown – factors such as solar gains and option, which is enabled by is the importance that UFH water internal gains from people, cooking, reversing the GSHP operation. It is temperature plays in the overall lighting and other appliances can feasible that this could be utilised efficiency of the GSHP system. also affect the room heat loss in the summer by circulating cool – then room temperature control water around the underfloor piping for individual rooms is usually to provide some degree of comfort Recommended further reading: recommended. It is normal practice cooling. If comfort cooling is • Domestic Ground Source Heat to run GSHP systems 24 hours per specified then careful consideration Pumps : Design and installation day to eliminate start up loads and should be given to the design of of closed-loop systems. make the most of cheaper rate the underfloor heating and cooling electricity tariffs. Energy Best Practice in Housing system. To gain the maximum www.est.org.uk/bestpractice Buffer tank or hot water cooling capacity of around 45 thermal store W/m2, the floor should be of solid • Renewable Energy Fact Sheet 5 A buffer tank or thermal storage screed/concrete construction and on Ground Source Heat Pumps cylinder is often used between the have negligible floor covering Energy Savings Trust GSHP and the UFH system. They resistance, e.g. tiles, slate, marble, www.est.org.uk/schri both provide a buffer of stored stone etc. In addition to this, pipes hot water for the UFH system, but should be tightly spaced and a have the benefit of reducing the water temperature difference of cycling of the GSHP, and allowing around 3oC is desirable. The control the use of controls to open/close system will need to incorporate loops on the UFH system, i.e. winter/summer changeover individual room control. A thermal and controls, and to store will normally have a section eliminate the risk of condensation, towards the top to produce hot include for dew-point control water and may have additional sensor(s). It is important that both connections for a solar panel and/or the GSHP and the UFH suppliers other heat generator. An electrical are informed when cooling is being immersion heater is often used for considered. supplementary heating and backup purposes. Generating domestic  Product Range Energy Systems

Uponor Energy Systems Pipe, Fittings and Accessories Description Code Pack Price Description Code Pack Price Qty per/m Qty each (£) (£)

Double-walled collector with return elbow attached Wall elbow 40mm. ES659937 1 15.59 for rock and lake energy heat pumps L = 1m Lead time approx 6 weeks. PEM 40x2.4, 2x50m ES648001 50m 3.42 PEM 40x2.4, 2x80m ES648004 80m 3.42 PEM 40x2.4, 2x100m ES648006 100m 3.42 Snap-in lid 315mm for ES352595 1 4.05 PEM 40x2.4, 2x150m ES648011 150m 3.42 inspection chamber PEM 40x2.4, 2x200m ES648016 200m 3.42 PEM 40x2.4, 2x250m ES648037 250m 3.42

Round nodular iron ES261902 1 155.95 cover for asphalt garage driveway

Square nodular iron ES261903 1 158.34 cover for paved garage driveway

Bottom parts and sinking weights for the plastic collector for rock and lake energy systems. Lead time approx 3 weeks. Return elbow for rock ES659878 1 12.93 or lake collector with Single-walled collector for ground energy mounting ring for Ex Stock. bottom weight or 40x2.4 100m ES640919 100m 1.63 hauling rope. 40x2.4 200m ES641219 200m 1.63 Pipe connection 40mm. 40x2.4 250m ES642819 250m 1.63 40x2.4 300m ES641519 300m 1.63 Round bottom weight ES659880 1 25.27 40x2.4 400m ES642919 400m 1.63 made from compact 40x2.4 500m ES643319 500m 1.63 concrete with a fastening hook for return elbow and a fastening hook for series connection of further bottom weights. Diameter = 85mm and length = 0.5m. Equivalent to a 12kg weight made from Description Code Pack Price ordinary concrete. Qty each (£) Distance weight 12kg ES659947 1 12.10 Top parts to plastic collector for energy well normally mounted at Lead time approx 3 weeks. c/c 3m for 40mm pipe. Rubber hood, pressure ES659917 1 59.31 Local conditions can sealed 138-168mm affect the weight setting.

Nylon fastening tape ES699996 1 0.25 Expander cap for 370mm (not included steel pipe 168mm ES659892 1 38.67 in the price for the Expander cap for steel weights) pipe 138mm ES659927 1 34.87 Plastic pipe insulation and other installation material Lead time approx 3 weeks. Tubolit DG 42/9 ES659894 2m 3.04 PEM 40 x 3.7 PN 10 ES640119 6m 11.92 2 metres for 40mm pipe 6m straight length

Yellow marker ES659920 250m 31.86 band 125mm PEM 40 x 2.4 PN 6.3 ES640019 6m 8.41 250-metre roll 6m straight length

Tee pipe 40mm with ES659918 1 19.32 venting nipple for electric socket fusion

 Uponor Energy Systems Pipe, Fittings and Accessories Description Code Pack Price Description Code Pack Price Qty each Qty each (£) (£) Electrofusion pipe fittings for collector 40mm MDPE Compression Fittings Lead time approx 3 weeks. Lead time approx 3 weeks.

Straight connector 40mmx1¼”x40mm MT 40mm ES695604 1 5.09 take off tee ES516040E 1 29.65 40mmx1½”x40mm MT take off tee ES516040F 1 29.65 Elbow 88.5o 40mm ES695643 1 3.01 40mm 90O Elbow ES5130400 1 24.72

Elbow 45o 40mm ES695641 1 2.96 40mmx1” Male thread adaptor ES511040D 1 14.55 40mmx1¼” Male o Branch 88.5 thread adaptor ES511040E 1 14.55 40-40mm ES695614 1 5.30 40mmx1½” Male thread adaptor ES511040F 1 14.55 Branch 45o 40-40mm ES695537 1 5.36 40mmx1¼” Male thread elbow ES519040E 1 15.56 UV-stabiliser fitting 40mmx1½” Male 40-R20mm ES695591 1 7.93 thread elbow ES519040F 1 16.30 40-R25mm ES695592 1 13.02 40-R32mm ES695593 1 11.18 40-R40mm ES695594 1 10.70 40mmx1¼” Female thread elbow ES518040E 1 20.26 40mmx1½” Female End cap thread elbow ES518040F 1 20.26 40mm ES695584 1 1.61

Description Code Pack Price Tools Qty each (£) Description Code Pack Nett Qty Price MDPE Compression Fittings each (£) Lead time approx 3 weeks. Assembly aid for the collectors 40mm Straight ES5100400 1 24.67 Lead time approx 6 weeks. coupling Collector spool ES018230 1 540.00 40mm x1” Female thread adaptor ES601040D 1 14.55 40mm x1¼” Female thread adaptor ES601040E 1 14.55 Pipe cutters 16-40mm ES018237 1 23.35 Pipe cutters 50-63mm ES018238 1 77.25 40mmx1”x40mm FT take off tee ES515040D 1 29.65 Chamfering tool ES018236 1 19.00 16-63mm 40mmx1¼”x40mm FT take off tee ES515040E 1 29.65

Electrofusion ES016505 1 420.00 apparatus 40mm End plug ES5210400 1 14.32

40mm Equal tee ES5140400 1 34.57

 Uponor Pre-Insulated Pipe

Uponor Pre-Insulated Pipe The Advantages: Uponor Pre-Insulated Pipe is the Easy to handle: proven name for the innovative, Easy to handle: low-weight and flexible, pre–insulated plastic piping highly flexible, the pipe can be system to transport a variety of installed around any obstacle. liquids both inside and outside No need for special tools of buildings. The system also for assembly: comprises a complete range of No special-purpose tools products for heating and hot and what so ever are needed for any cold water supplies. phase of the assembly. Its material properties give long “Endless” pipe lengths from service life and as the pipes are low- the coil: weight and highly flexible, they can No connections nor be installed easily and quickly, even compensators - just roll off the over obstacles and round corners. length of pipe you need! Uponor Pre-insulated pipe can Fixed lengths - delivery service: be used for a wide variety of Pipes can be cut to size as applications, a few of which are required and delivered direct to detailed below. the construction site - saving By Medium time and money! • Potable Water Rapid work progress: • Heating Water Small trenches and quick, easy • Cooling Water installation and job progress is • Sewage guaranteed! • Foodstuffs and Chemicals Service: From the planning phase to By Use work completion we can offer Connecting up individual • you a comprehensive service buildings package. • Construction of a supply network • Urban engineering • Liquids for industry (2) (3) (1) (4)

(1) Ribbed jacket pipe made of impact proof polyethylene. Very flexible with high load bearing capacity (2) Excellent low weight PEX foam heat insulation (3) The two coloured ‘dog bone’ prevents mix ups in flow and return connections (4) Corrosion proof, oxygen impermeable carrier pipe made of PEX material

1 0 Uponor Pre-Insulated Pipe Uponor Pre-Insulated Pipe product range. Aqua Single This overview will give you an • PE-X pipe for potable water, hot initial impression of the Uponor water Max. 95 °C/10 bar •Approved by the German Water Pre-Insulated Pipe programme and Gas Board and primary applications. It •Carrier pipe 25, 32, 40, 50, 63 ø mm is supplemented by available •Trace heating cable on request pipe couplings, T-pieces, bends, chambers, wall sleeves etc. – in Aqua Twin brief – everything you need for a • PE-X pipe for potable water, hot water complete Uponor Pre-Insulated Max. 95 °C/10 bar Hot water and circulation pipe in one jacket Pipe system. • •Approved by the German Water On request, we can send you and Gas Board Carrier pipe 25/25, 32/25, 40/25 detailed work sheets, delivery • and 50/25 ø mm program and price list or our product catalogue with installation Quattro instructions. • 4-line pipe, combination of Aqua Twin and Thermo Twin Tailor-made lengths, delivered •Suitable for building connection from exactly when you need them. mains via chamber We offer you our Uponor Pre- Insulated Pipe Cut to Measure Service, if you need to have exact material specifications for your Supra construction project, as fixed Single PE-100, Max. 20 °C/16 bar • for potable water, cold water, waste water lengths can save you costs. transport, cooling water No unnecessary time loss. •25 -110 ø mm On request with frost-protection cable No unnecessary wastage. No • unnecessary disposal costs. And what you order will be delivered as quickly as possible to Thermo Single where you need it. • Single PE-X pipe with EVOH for heating water Max. 95 °C/6 bar Also available are pipe couplings, •Carrier pipe 25 -110 ø mm T-pieces, bends, chambers, wall •On request with trace heating cable sleeves etc. – everything you need for complete Uponor Pre-Insulated Pipe systems. Thermo Twin • Twin PE-X pipe with EVOH for flow and return lines •2 x 25, 2 x 32, 2 x 40, 2 x 50, 2 x 63 ø mm

Thermo Mini Single PE-X pipe with EVOH for heating • water Max. 95 °C/6 bar with small jacket pipe •Carrier pipe 25 and 32 ø mm •On request with trace heating cable

Uponor Pre-Insulated Pipe 1 1 UGSHP-Oct 2007 W E F T LE17 4HN Leicestershire Lutterworth Rugby Road Snapethorpe House Uponor HousingSolutionsLtd

and cooling. ferred energy isidealfor heating closed loopcircuit. The trans geothermal energy through the The GSHPtransfers thestored available landsurface islimited. These are theidealchoice when Vertical loops(‘borehole’) and into yourhome. stored inthesoilthrough theloops The GSHPtransfers thesolarenergy adequate landsurface isavailable. These are oftenconsidered when Horizontal Loops (‘slinkies’)

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01293 655488 the pondorlake. are simplyplaced onthebottom of eliminated. Coilsofpipe virtually because excavation costs are when abodyofwater isavailable, These are economical to install Pond (Lake) Loops product development. ofourpolicycontinuous at anytimeaspart our UnderfloorHeating&Plumbing Systems specifications andoperating parameters for all Uponor reserves therightto alter time ofgoingto press. information inthispublicationiscorrect atthe manuals for fullup-to-date information. The guideline only, pleaseconsult ourtechnical The contents ofthisbrochure are provided for Solutions Ltd. prior written permission ofUponorHousing for anypurposeisnotpermitted withoutthe Reproduction ofthispublication ofanypart Solutions Ltd.) Copyright ©Uponor(UponorHousing W E F T Co. Dublin,Ireland Seatown Road, Swords Unit 13,Seatown BusinessCampus Specification Centre, Ireland

00 353(0)18957430 www.uponorhousingsolutions.ie 00 353(0)18957434 [email protected]