LAUSR

Abstract The feasibility of solar-assisted absorption heat pumps for space heating is assessed with exergoeconomics and compared with gas boilers and solar heating systems for the town of Sarein in Iran. In the study, single-effect LiBr/H2O and NH3/H2O absorption and absorption compression-assisted heat pumps are analyzed for heating loads of 50–2 MW. Using the geothermal hot springs located in Sarein as heat sources for refrigerant evaporation, the problem of freezing is prevented. In addition, a multi-objective optimization is performed to specify the optimal design points considering the temperatures of the evaporator and generator as decision parameters. Simulations show that the gas boiler and the solar heating system have the lowest and second lowest values of exergy efficiency, at about 45% and 35% lower than the exergy efficiency for NH3/H2O absorption systems. The maximum achievable exergy efficiency for the NH3/H2O and LiBr/H2O absorption systems are 0.23 and 0.25, respectively. But, the solar heating system has the highest product unit cost, mainly due to its high capital costs. The minimum obtainable product unit costs for the NH3/H2O and LiBr/H2O absorption systems occur in April, and are about 22 $/GJ and 55 $/GJ, respectively.