New absorption chillers for high efficient solar cooling systems Dipl.-Ing. Stefan Petersen & Dipl.-Ing. Jan Albers Foto: TU Berlin Foto: TU Berlin 1. General Technology Overview 2. Operating data 3. Solar cooling system layout 4. Showcase results 1
Solar air-conditioning technologies electrical systems thermal systems - PV + Vapor compression chiller - liquid sorbent closed cycles solid sorbent heat transformation processes liquid sorbent open cycles solid sorbent thermomechanical processes - steam jet cycles - rankine cycle + vapor compression chiller - absorption chiller adsorption chiller desiccant and evaporative cooling (DEC) 2
Basics compression chiller inner cycle condenser steam cooling water refrigerant throttle compressor electric power chilled water evaporator steam water-cooled vapor compression chiller [1] liquid refrigerant vaporous refrigerant [1] Carrier 3
Basics absorption chiller inner cycle condenser steam desorber cooling water hot water refrigerant throttle Chilled water evaporator steam absorber cooling water 10 kw Phönix-absorption chiller- TU Berlin refrigerant diluted solution concentrated solution 4
0, 7 0, 6 0, 5 0, 4 0, 3 0, 2 New absorption chillers for high efficient solar cooling systems Short general characteristic 70 60 Cooling Capacity [kw] 50 40 30 20 10 Nominal load 8New 50 kw Chiller 0, High efficient10 kw 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 COP [-] 0 24 29 34 39 44 49 Reject Heat Inlet Temperature [ C] 0.0 5
System setup thermal system configuration Heat transformation process Basic system configuration Storage almost inevitable 6
70 Variability Driving Heat Source I @ t_rh=30 C, V_RH=3,8kg/s, t_cw=21/16 C Cooling Capacity [kw] 60 50 40 30 20 dt @40kW 13K 40K 0,9 l/s 0,6 l/s 0,3 l/s 0,1 l/s 10 0 50 60 70 80 90 100 Heat Source Inlet temperature [ C] 7
0.9 Variability Driving Heat Source II @ t_rh=30 C, V_RH=3,8kg/s, t_cw=21/16 C COP [-] 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 dt in/out < 13K @77/64.. to.. 40K @97/57 Volumenstrom flow 0.9 l/s Volumenstrom flow 0.6 l/s Volumenstrom flow 0.3 l/s 0.0 0 10 20 30 40 50 60 70 Cooling capacity [kw] 8
60 Variability Reject Heat Sink I @ t_dh=90 C, V_DH=0,9kg/s, t_cw=21/16 C 3,8 l/s 50 Cooling Capacity [kw] 40 30 20 10 2,0 l/s 1,5 l/s 1,0 l/s P hydraulic = 1/64*nominal = 1.5% P hydraulic = nominal =100% 0 25 30 35 40 45 Reject Heat Inlet Temperature [ C] 9
2 1,5 1 Energetic comparison including auxiliaries auxiliary power demand p a =0 p a =1% p a =10% break even 0,5 0 0 0,2 0,4 0,6 0,8 1 Solar fraction 10
SAC-System UBA Dessau image source: Busse 11
Concept for solar cooling system (Dry) reject heat device KKM Compression chiller District heating AKA Solar Collectors Hot water storage Absorptionschiller Chilled water storage Cold consumer 12
SAC-System UBA Dessau Temperature collector outlet Temperature top of storage Solar driving temperature Chilled water outlet 13
Operating data and control Temperatur / C, Volumenstrom / (m³/h), Strahlung / (10 W/m²) 100 90 80 70 60 50 40 30 20 Solar driving temperature Temperature at top Speicher of storage 1 oben Antriebstemperatur solar Flow rate in collector circuit Volumenstrom Kollektorkreis Temperatur Kollektoraustritt Temperature at collector outlet Solarstrahlung Horizontal horizontal irradiation 10 Driving Entladevolumenstrom flow rate to chiller 0 04:00 08:00 12:00 16:00 20:00 Uhrzeit am 03.09.2011 14
Regelung und Betriebsergebnisse 100 90 Temperatur / C, Leistung / kw 80 Driving Antriebstemperatur temperature 70 60 Temperatur Reject heat Kühlwasser inlet temperature Eintritt 50 Driving Antriebstemperatur temperature (Sollwert) Kälteleistung Cooling load (Sollwert) (set value) 40 (set point 30 20 Cooling Kälteleistung load 10 Temperatur Reject heat Kühlwasser inlet temp. (Sollwert) (set value) Temperatur Chilled water Kaltwasser temperature Austritt 0 04:00 08:00 12:00 16:00 20:00 Uhrzeit am 03.09.2011 15
Results of first year Previous year with adsorption chiller Aug. 2010 Jul. 2011 First year with new absorption chiller Aug. 2011 Jul. 2012 Change Cold generation 104 MWh 0 59 MWh 0 Driving heat 221 MWh th 80 MWh th Thermal efficiency 0,47 MWh 0 /MWh th 0,76 MWh 0 /MWh th +62% Electrical efficiency 2,9 MWh 0 /MWh el 4,5 MWh 0 /MWh el +55% Water consumption 4,0 m³/mwh 0 1,3 m³/mwh 0 68% 16
Control Issues: Parasitic electricity consumption Control Strategy SEER el SEER th Classic 12,4 0,76 +Reject heat, vol.flow 17,8 0,75 +Hot Water, vol.flow 13,6 0,76 +vol.flows +reject heat temp. 20,1 0,75 SEER = Seasonal Energy Efficiency Ratio 17
Conclusion Development started in 2008 with case studies and optimization: - Thermodynamic design - Manufacturing process - Cost efficiency Final chiller concept fixed in 2009 Starting of pre-industrial manufacturing and laboratory measurements in 2010 Installation of first prototypes in Berlin and Dessau in 2011 Commercial launch in 2013: - high energy efficiency (COP > 0,75) - high energy density and compactness - high cooling water temperatures > 45 C - low driving temperatures (t start < 60 C) - low investment (~300 /kw) Foto: TU Berlin 18