Laboratory and operational analysis of air to water gas absorption heat pump cycle

Abstract

Gas absorption heat pumps (GAHP) have significant potential to reduce fossil fuel consumption for space heating and hot water production and reduce CO2 emissions. The paper deals with laboratory and operational verification of GAHPs operating with air as a low-temperature energy source. The laboratory verification was used to specify and analyse the courses of one GAHP cycle in terms of cycle phases, outputs, and operating temperatures at different temperatures of the air supplied to the evaporator and heating water temperatures from GAHP. Comparative operational verification was conducted simultaneously in two identical buildings with the same technology and on two identical GAHPs A. The influence of interventions in GAHP control on the operating parameters and the average time of one cycle was monitored. The decrease in outdoor temperature and the transition from using the GAHP for water heating only to using it for space and water heating significantly affected the performance parameters and the average cycle time. Validation measurements were carried out for one year in twelve boiler rooms with GAHP connected in a cascade with gas-condensing boilers. The results showed that in the seasonal evaluation of GAHP operation for space and water heating, the average operation time of GAHP did not significantly affect the performance parameters. A fixed operation control to a higher required temperature of heating water when applying GAHP for space and water heating significantly negatively affected the performance parameters. Compared to heat production from a gas-condensing boiler (GCB), the monitored GAHP operation had lower emissions by 52 kg of CO2 per 1 MWh of heat produced.