Performance assessment of a solar-assisted absorption-compression system for both heating and cooling

Combining renewable energy with building energy supply is an effective way to pivot the building sector to carbon–neutral. This paper proposes a novel solar-assisted energy supply system which is applied in residential buildings for heating, cooling and domestic hot water. The heating/cooling output of the proposed system is mainly contributed by a vapor compression system to address the supply–demand mismatch of solar energy supply system, and the other part is assumed by a solar driven absorption system that is operating with lower generation temperature and higher evaporation temperature to assist the vapor compression system. Therefore, a solar-assisted absorption-compression system (SAACS) exploits the full potential of solar heat for annual energy supply by improving the contribution of per unit solar collection area, with considerable electricity-saving compared to air-source heat pumps. A thermodynamic model is established and validated by the results of the built experimental prototype which is testing. Solar-assisted heating mode and solar-assisted cooling mode are compared in comprehensive evaluation criteria to illustrate the performance differences caused by the assisted solar energy. The results indicate that solar heat at 60 °C is feasible for heating and cooling, revealing the great potential for efficient conversion from solar energy for heating and cooling. Due to the introduction of solar energy, the cooling and heating COPele increases by 10.3 % ∼ 17.6 % and 32.3 % ∼ 56.3 %, respectively. Despite the lower increase in COPele, electricity-saving ratio shows greater value at low hot water temperatures, varying from 24.3 % to 19.6 % for cooling and from 44.1 % to 39.7 % for heating as hot water temperature increases from 60 °C to 85 °C. The maximum SCOP is 0.63 for cooling, and 1.14 for heating. Yearly investigation shows that the SAACS combined with 20 m2 CPC collector has an annual average solar fraction of domestic hot water of 0.85 and a discounted payback period of 3.12 years. These results demonstrate the feasibility and flexibility of the SAACS applied to residential buildings toward decarbonization. •Flexible modulation of solar energy enable application for residential buildings.•Thermodynamic model and experimental prototype are implemented.•Both heating and cooling supply make use of solar energy.•Heat driven temperature is as low as 60 °C.•Discounted payback period is 3.12 years.