Development of hybrid solar-assisted cooling/heating system

Abstract

A solar-assisted ejector cooling/heating system (SACH) was developed in this study. The SACH combines a pump-less ejector cooling system (ECS) with an inverter-type heat pump (R22) and is able to provide a stable capacity for space cooling. The ECS is driven by solar heat and is used to cool the condenser of the R22 heat pump to increase its COP and reduce the energy consumption of the compressor by regulating the rotational speed of the compressor through a control system. In a complete SACH system test run at outdoor temperature 35 °C, indoor temperature 25 °C and compressor speed 20–80 Hz, and the ECS operating at generator temperature 90 °C and condensing temperature 37 °C, the corresponding condensing temperature of the heat pump in the SACH is 24.5–42 °C, cooling capacity 1.02–2.44 kW, input power 0.20–0.98 kW, and cooling COP c 5.11–2.50. This indicates that the use of ECS in SACH can effectively reduce the condensing temperature of the heat pump by 12.6–7.3 °C and reduce the power consumption by 81.2–34.5%. The SACH can also supply heat from the heat pump. At ambient temperature from 5 °C to 35 °C, the heating COP h is in the range 2.0–3.3.