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Modern HVAC-systems for nearly zero energy buildings Maija Virta M.Sc.(Eng.) Head of Operations, Santrupti engineers Fellow of REHVA,Member of ASHRAE Federation of European Heating, Ventilation and Air-conditioning Associations 1 Technologies Used in Zero Energy Buildings • Reduced Energy Need • Reduced System Energy Use – Active and passive beams – DOAS – Chilled ceilings and TABS • Energy recovery • Dehumidification – Radiant floor cooling (&heating) • Adiabatic & desiccant cooling – Displacement ventilation – Evaporative cooling – UFAD (under floor air diffusion) – Demand based ventilation – Natural and hybrid ventilation – Earth tubes – Night purge ventilation – Condensing boilers – Personal ventilation • On-site Energy Production – Active solar shading – District heating and cooling – LED lighting – Heat pumps – Light tubes (daylight) – Solar heat – BMS – Solar cooling Focus of this presentation is on – Photovoltaic (PV) underlined HVAC technologies – Wind turbines Federation of European Heating, Ventilation and Air-conditioning Associations 2 Passive Chilled Beams Federation of European Heating, Ventilation and Air-conditioning Associations 3 Main Principles of Passive Chilled Beam • Passive chilled beams comprise a heat exchanger for cooling, and when desired for heating. • The operation is based on natural convection. • The primary air is supplied to the space using separate diffusers either in the ceiling or wall, low velocity units at low level or alternatively through the raised floor. Federation of European Heating, Ventilation and Air-conditioning Associations 4 Active Chilled Beams Federation of European Heating, Ventilation and Air-conditioning Associations 5 Chilled Beam Operation 1. Primary air (dehumidificated outdoor air) supply into supply air chamber 2. Primary air is supplied through small nozzles. 4 3. Primary air supply induces room air to be re-circulated through the heat exchanger of the chilled beam. 2 1 3 4. Re-circulated room air and the primary air are 5 mixed prior to diffusion in the space 5. Cold water connection 6 6. Warm water connection Federation of European Heating, Ventilation and Air-conditioning Associations 6 Chilled Beam Operation Exposed chilled beam for installations Closed chilled beam for installations without suspended ceiling with suspended ceiling Federation of European Heating, Ventilation and Air-conditioning Associations 7 Federation of European Heating, Ventilation and Air-conditioning Associations Federation of European Heating, Ventilation and Air-conditioning Associations Federation of European Heating, Ventilation and Air-conditioning Associations Federation of European Heating, Ventilation and Air-conditioning Associations Chilled Ceilings Federation of European Heating, Ventilation and Air-conditioning Associations 12 Federation of European Heating, Ventilation and Air-conditioning Associations Total Cooling Capacity 19 OC O 40 OC 26 C 37 OC 26 OC Radiation: 5.5 W/m2,K O O 2 toperative = 25 C, tsurface = 19 C, Pradiation = 33 W/m (dt=6K) 19 OC 26 OC 26 OC 40 OC 37 OC Natural Convection: Air movement in space (convection): 2 Pconvection = 65 – 33 = 32 W/m (dt=6K) Asymmetric plumes of heat sources 0…-15 % Air diffusion 0…+20 % Federation of European Heating, Ventilation and Air-conditioning Associations Federation of European Heating, Ventilation and Air-conditioning Associations Thermally Active Building Systems (TABS) Federation of European Heating, Ventilation and Air-conditioning Associations 16 Federation of European Heating, Ventilation and Air-conditioning Associations www.naturalcooling.com Federation of European Heating, Ventilation and Air-conditioning Associations Floor Cooling Federation of European Heating, Ventilation and Air-conditioning Associations 19 Federation of European Heating, Ventilation and Air-conditioning Associations Displacement Ventilation Federation of European Heating, Ventilation and Air-conditioning Associations 21 Displacement Ventilation System • Thermal displacement ventilation is based on cool air supply at low level and stratification of room air temperature and contaminants due to natural buoyancy forces of the heat gains. Federation of European Heating, Ventilation and Air-conditioning Associations 22 Lower Energy Consumption in Cooling and Better IAQ Height Contaminants are carried above the shift zone by convective plumes thus air in the occupied zone is cleaner By cooling occupied zone only, the required airflow rate & cooling capacity may be reduced Temperature, Contaminants Federation of European Heating, Ventilation and Air-conditioning Associations 23 Federation of European Heating, Ventilation and Air-conditioning Associations 24 Federation of European Heating, Ventilation and Air-conditioning Associations 25 ? Federation of European Heating, Ventilation and Air-conditioning Associations 26 Air Distribution Principles in Auditoriums 8 l/s,person a) Supply air is contained b) Supply air is foating down between the rows. the stairways. 16 l/s,person Federation of European Heating, Ventilation and Air-conditioning Associations 27 Federation of European Heating, Ventilation and Air-conditioning Associations 28 Federation of European Heating, Ventilation and Air-conditioning Associations 29 Types and Variation of Current UFAD Supply Air Return Air • Positive pressure plenum • Ceiling plenum (unducted, “push” type) – Ducted – Grille, diffuser – Partially ducted – VAV-unit – Unducted • Neutral pressure plenum • High sidewall grille – Ducted to VAV or Fan coil unit • (Floor plenum ducted to grille or – Unducted, “pull” type fan coil unit) • Fan powered VAV • Fan coil unit • Fan powered diffuser Federation of European Heating, Ventilation and Air-conditioning Associations 30 Ceiling cooling elements combined with displacement ventilation • Low velocity air supply combined with cooling elements at the ceiling level behave like mixing system when the cooling elements provide a substantial part of the cooling. 2,50 Cooled ceiling 2,00 = 0 1,50 = 0,4 = 0,5 1,00 = 0,6 = ratio of the cooled 0,50 ceiling cooling output to Height above floor level, z [m]z level, floor above Height the total cooling output (Tan 1998) 0,00 0,8 1,0 1,2 1,4 Relative air temperature (relative to temp. at 0,1 m above the floor) Federation of European Heating, Ventilation and Air-conditioning Associations 31 Dedicated Outdoor Air System (DOAS) • 100% outdoor air is delivered to each zone via its own ductwork • Outdoor air is conditioned in DOAS unit – Filtered / cooled / heated / dehumidified / humidified • Exhaust fan & filter is integrated into a same air handling unit • Air flow rate: – To fulfill air flow rate specified by ASHRAE Std. 62.1 / EN 15251 or greater – To satisfy cooling/dehumidification demand in space (sensible and latent) – Can be either constant volume (CAV) or demand based • Energy recovery can be integrated • Predictable ventilation control and improved indoor air quality • Energy efficiency is dependent on air volume and system design – Good efficiency with water cooling (e.g. chilled beams and chilled ceilings) Federation of European Heating, Ventilation and Air-conditioning Associations 32 Cross-flow heat exchangers • Separation of the two air flows • No transfer of moisture or odour • Easy maintenance • Optional bypass & circulation air damper Federation of European Heating, Ventilation and Air-conditioning Associations Thermal wheel heat exchanger • Heat recovery up to 85% • Transfer of latent heat possible • Aluminium foil accumulator mass • Speed 1 - 10 rpm • Easy maintenance Federation of European Heating, Ventilation and Air-conditioning Associations Latent (internal, external) and part of the sensible loads are taken care in AHU Round-around and cooling coil (10 kW) 70 kW (10 kW) Side view Wolf GmbH 84048 Mainburg 5.2 kW Telefon 08751/74-0 52 52 30 30 Fax 08751/741574 www.wolf-klimatechnik.de O O O O Airvolume-supply side: 10000 m³/h 41 C 29 C 24 C 13 C 17 OC 35 % 53 % 70 % 95 % 913 4 5 6 7 8 913 1017 1218 701218 % Airvolume extract: 9500 m³/h 19 g 13.3 g 13.3 g 9.5 g 9.5 g Length of projection of damper linkage max. 120 mm from external unit surface, parallel to damper fins. 52 52 30 2 1 3 30 2034 26 OC 55 % 913 10 9 913 1017 1218 11.5 g 2 g/kg from internal 1218 moisture sources, dependent on supply air 3.0 kW Sorption wheel volume 1621 Planview 509 400 712 Federation of European Heating, Ventilation and Air-conditioning Associations 52 260 52 30 30 913 10 2 1 3 9 913 1218 1218 1322 1932 120 R1 712 509 400 712 712 3045 305 10 Fan section ca. 120kg 9 Bagfilter F7 (short) ca. 31kg Planview 8 Heating section ca. 43kg 7 Cooling section ca. 120kg 6 Cooling section ca. 58kg 52 260 52 30 30 5 Fan section ca. 87kg 4 Bag filter F9 (short bags) ca. 48kg 3 Air diffusion section ca. 22kg 2 Air diffusion section ca. 16kg 1 Rotary heat exchanger ca. 300kg Total weight ca. 845kg 913 4 2 1 3 5 6 7 8 913 1322 1218 1218 1932 Client: Project name: Sorption wheel with diffusion sections Position: 15.11.2012 Responsible: 120 Date Name R1 Project no.: / 712 509 400 712 712 610 610 305 305 4570 R1 = Access door KG Top 130 AHU selection without and with different energy recovery systems in Delhi during summer Indirect adiabatic Sensible wheel Direct Delhi, summer adiabatic Crossflow heat exchanger No energy recovery Sorption wheel Room air Supply air Federation of European Heating, Ventilation and Air-conditioning Associations Temperature reduction with different energy recovery systems in Delhi during summer Delhi, summer Crossflow heat
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