Energetic and exergetic investigation of a novel solar assisted mechanical compression refrigeration system

Highlights: • A novel solar assisted mechanical refrigeration system with ETC is investigated. • A vessel is inserted after the compressor where thermal compression is achieved. • The parametric analysis is performed in energetic and exergetic terms. • The results proved electricity savings in all the examined cases. • About 15% electricity savings are achieved with 2 m²/kW specifying collecting area. - Abstract: The objective of this study is to present and to examine a novel solar assisted mechanical compression refrigeration system. Evacuated tube collectors are used in order to partially thermally compress the refrigerant, after the mechanical compressor. This design aims to reduce the electricity consumption using a renewable energy source, creating a sustainable system. The suggested design is analyzed parametrically in order to investigate its energetic and exergetic behaviour in various operating conditions and it is examined with EES (Engineering Equator Solver) in steady state conditions. The temperature levels in the evaporator and in the condenser, as well as the thermal compression fraction (expressed with the pressure ratio parameter), are the examined parameters. The final results proved that the optimum values of the pressure after the mechanical compressor is the 75% of the maximum pressure and for this case, energy savings from 15% to 25% can be achieved. Moreover, the specific collecting area is found to be relatively low, close to 2 m²/kW for the optimum cases. The final results proved that the new design leads to energy savings in all the examined cases and especially in cases with higher evaporating temperature levels, a fact that makes it ideal for space cooling applications.