Mikkelin university of applied sciences Building services COOLING OF BUILDINGS 26.11.2010 Kuva: Pemco Mikkelin university of applied sciences Building services Principal lecturer (TkL) Aki Valkeapää aki.valkeapaa@mamk.fi Martti Veuro, senior lecturer 20.11.2018 Aki Valkeapää

COOLING OF BUILDINGS Cooling of buildings is based on atleast still compressor cycle where the cooling medium / refrigerant is evaporated (heat transfer from surroundings to the refrigerant) and condensed (heat transfer from refrigerant to the surroundings, heat is rejected) in turn. This cycle and the required pressure difference between evaporator (low pressure) and condenser (high pressure) is maintained by the compressor. Kuva: Danfoss 20.11.2018 Aki Valkeapää

COOLING OF BUILDINGS Kuvat: Danfoss, Fincoil, Coiltech 20.11.2018 Aki Valkeapää

COOLING OF BUILDINGS Condensing pressure and temperature in the condenser Amount of rejected heat by condensation of refrigerant Saturated liquid Pressure difference across expansion valve Saturated vapour Amount of heat for evaporation of refrigerant Evaporation pressure and pressure Reference: Aittomäki 2008 20.11.2018 Aki Valkeapää

L L+V V C B A COOLING OF BUILDINGS COP2 (EER) = HEAT NEEDED /HEAT REJECTED = (B-C)/(A-B) 20.11.2018 Aki Valkeapää

- ODP(ozone depletion potential) - GWP (global warming potential) COOLING OF BUILDINGS refrigerants - ODP(ozone depletion potential) - GWP (global warming potential) - CFC – substances (Chloro-Fluoro-Carbon), e.g. R12 (ODP=1, GWP=8100) - HCFC -substances, e.g. R22 (ODP=0,055, GWP=1500) -HFC -substances, R134a, R404A, R407C, R410A (ODP=0, GWP=1300…3260) - ammonia (ODP=0, GWP=0) - CO2 carbon dioxide (ODP=0, GWP=1) - HC-refrigerants, e.g. isobutane R600a is common in household refrigerators (fridges) 20.11.2018 Aki Valkeapää

Mechanical thermostatic expansion valve COOLING OF BUILDINGS Mechanical thermostatic expansion valve Lähde:Danfoss 20.11.2018 Aki Valkeapää

The future solutions of cooling do not seem to be simpler than today COOLING OF BUILDINGS Compressor cooling can be realized as a centralised or decentralised system Centralised or decentralised cooling system can be executed either with a direct system or with an indirect system Centralised or decentralised cooling system can be executed either with a direct condensing or with an indirect condensing Rooms / spaces can be cooled / air conditioned with supply air or with chilled water or both of them can be used at the same time Addition to those also there is systems like district cooling, night ventilation, utilization of ground or water “cold”, heat pumps,... The future solutions of cooling do not seem to be simpler than today 20.11.2018 Aki Valkeapää

AIR CONDITIONING SYSTEM ALTERNATIVES COOLING SYSTEM direct cooling – direct condensing direct cooling – indirect condensing indirect cooling – direct condensing indirect cooling – indirect condensing indirect cooling – indirect condensing + free cooling indirect cooling – direct condensing + free cooling indirect cooling – indirect condensing + gliding / floating condensing pressure + free cooling (?) AIR CONDITIONING SYSTEM cooling with supply air cooling with chilled water (and supply air) cooling with circulating air 20.11.2018 Aki Valkeapää

DECENTRALISED DIRECT COOLING Compressor +condenser evaporator Figure: Koja Figure: Koja vakioilmastointikone Direct condensing vakioilmastointikone Indirect condensing (fluid) split-unit (refrigerant cycle) Reference: Kaappola 1996 20.11.2018 Aki Valkeapää

(containing refrigerant) DIRECT COOLING Direct cooling coil (containing refrigerant) supply air Expansion valve Liquid refrigerant from the liquid tank or condenser discharge / hot gas to the condenser compressor 20.11.2018 Aki Valkeapää

heat recovery finned coil (condenser) exit air expansion valve CENTRALISED DIRECT COOLING (cooling machine in the air handling unit AHU) finned coil (condenser) Scroll-compressor exit air heat recovery expansion valve supply air direct cooling coil (evaporator) 20.11.2018 Aki Valkeapää

CENTRALISED DIRECT COOLING compressor (rotation speed controlled scroll-compressor) direct cooling coil (refrigerant) condensing coil (refrigerant) Photo: Intervent 20.11.2018 Aki Valkeapää

DIRECT COOLING – capacity regulator by hot gas by-pass Figure: Danfoss Lähde: Coiltech Reference: Seppänen 2004 Figure: Danfoss Figure: Srcoils Capacity regulator with a hot gas by-pass valve (9) (100% > 50%) - hot gas is injected between thermostatic expansion valve (7) and evaporator (8) – energy is wasted, better solution would be rotation speed controlled (scroll) compressor 20.11.2018 Aki Valkeapää

Air cooled condensing units A cooling system is executed with three compressor-condenser units and the direct cooling coil is divided into three horizontal sections. Refrigerating effect is controlled by the number of compressors in operation at the same time. Air cooled condensing units Reference: Seppänen 2004 Reference: Aittomäki 2008 Figure: Chiller Oy 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING CONSTANT AIR FLOW RATE Chiller ”plant” without separated condenser (A+B) with a separated condenser (A+B+C) C A B Reference: Seppänen 2004 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING CONSTANT AIR FLOW RATE, AIR CONDITIONING WITH CHILLED BEAMS Iv-kone = AHU Lauhdutin=condenser Vesisäiliö=water tank Vedenjäähdytin=chiller Ilmastointipalkki=chilled beam Kaukolämmön alajakokeskus= District heating substation Term.venttiili ja vesiradiaattori= Radiator thermostat and radiator Reference: Seppänen 2004 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING AIR CONDITIONING WITH FAN COILS Figure: Chiller Reference: Seppänen 2004 Figure: Fläktwoods 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING AIRCONDITIONING AND VAV (VARIABLE AIR VOLUME) Iv-kone=air handling unit Vedenjäähdytin=chiller Vesisäiliö=water tank Lauhdutin=condenser Reference: Seppänen 2004 20.11.2018 Aki Valkeapää

INDIRECT COOLING cooling coil (chilled water) compressor water or brine (liquid) charging circuit refrig. cycle plate heat exchanger (evaporator) chilled water tank 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND DIRECT CONDENSING WITH AIR COOLED CONDENSER Figure: Genemco Photo: Danfoss compressor condenser refrigerant cycle charging circuit expansion valve Figure: Fincoil plate heat exchanger (evaporation) Figure: Danfoss 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND DIRECT CONDENSING ”air cooled liquid chiller”, roof (outdoors) mounting TV 1 condenser Figure:Koja EVAPORATOR +27°C +7°C brine P1 +12°C 20.11.2018 Aki Valkeapää

INDIRECT CONDENSING AIR COOLED LIQUID COOLER refrigerant cycle Brine circuit Plate heat exchanger (condenser) Figure: Fincoil 20.11.2018 Aki Valkeapää

CHILLER WITH FREE COOLING AND INDIRECT CONDENSING P1 LS 1 LS 2 water brine TV 1 P2 brine P3 TV 3 TV 2 LS 3 Figures: Chiller 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND INDIRECT CONDENSING WITH FREE COOLING air cooled liquid cooler +42°C +36°C Summer case = compressor cooling +30°C P1 LS 1 LS 2 TV 3 water +12°C TV 1 P2 brine P3 TV 2 LS 3 +7°C 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND INDIRECT CONDENSING WITH FREE COOLING Air cooled liquid cooler winter case = compressor off temp. outdoors < +4°C +4°C P1 LS 1 LS 2 TV 3 water +14°C TV 1 P2 brine P3 TV 2 LS 3 +9°C 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND INDIRECT CONDENSING WITH FREE COOLING air cooled liquid cooler summer case = compressor cooling +36°C +42°C +30°C LS 3 P1 LS 1 LS 2 TV 3 water +14°C TV 1 P2 brine +7°C P3 20.11.2018 Aki Valkeapää

INDIRECT COOLING AND INDIRECT CONDENSING WITH FREE COOLING air cooled liquid cooler winter case = compressor off temp. outdoors < +4°C +4°C LS 3 P1 LS 1 LS 2 TV 3 water +9°C +14°C TV 1 VJK P2 brine P3 20.11.2018 Aki Valkeapää

CHILLER 200 … 700 kW Figure: Chiller 20.11.2018 Aki Valkeapää

CHILLER 1=screw compressor 2=tube bundle heat exchanger (condenser) 3=tube bundle heat exchanger (evaporator) 4=filter drier 5=solenoid valve 6=sight glass 7=expansion valve Reference: Kaappola 2007 20.11.2018 Aki Valkeapää

CHILLER Tube bundle heat exchanger as condenser: Figure: Bitzer Tube bundle heat exchanger as condenser: refrigerant in bundle outside tubes brine in tubes (non freezing liquid) Tube bundle heat exchanger as evaporator: refrigerant in tubes brine in bundle outside tubes (non freezing liquid) Reference: Aittomäki 2008 Figure: SEC heat exchanger 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING DIRECT CONDENSING 3-port control valves Refernce: Kaappola 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING DIRECT CONDENSING 2-port control valves Reference: Kaappola tasaussäiliö=chilled water tank 20.11.2018 Aki Valkeapää

CENTRALISED INDIRECT COOLING DIRECT CONDENSING chilled beam system, three port control valve Reference: Kaappola 20.11.2018 Aki Valkeapää

DISTRICT COOLING Figure : Helsingin energia jäähdytysverkko=district cooling network kaukojäähdytyshuone=DC tech. room jäähdytyskeskus=cooling plant asuintalo=residential building liiketila oy=offices and shops 20.11.2018 Aki Valkeapää

replaces a compressor cooling systems in a real estate DISTRICT COOLING replaces a compressor cooling systems in a real estate cooling is produced centrally, distributed through pipework to the real estates and is transferred with a heat exchanger to cooling pipework in the building (compare cf. district heating) temperatures - primary side +8°C / +16°C (DC network temp.) - cooling of AHU +10°C/+17°C - fan coils +15°C/+18°C or if condensing water from air +10°C/+18°C - chilled beam distribution network +15°C/+18°C secondary side with two port control valves 20.11.2018 Aki Valkeapää

? DISTRICT COOLING District cooling production in Helsinki Figure: Helsingin energia Vapaajäähdytys=free cooling lämpöpumppu=heat pump absortio=absortion 20.11.2018 Aki Valkeapää

Heat pump, wintertime DISTRICT COOLING Figure: Helsingin energia Meri=sea Jätevesi= waste water Lämmönvaihdin=heat exchanger Figure: Helsingin energia 20.11.2018 Aki Valkeapää

Heat pump, summertime DISTRICT COOLING Figure: Helsingin energia 20.11.2018 Aki Valkeapää