Field Test of Solar Assisted Cooling System
Abstract
A solar-assisted ejector cooling/heating system (SACH-2) was developed in this study. SACH-2 is designed in parallel configuration. The solar ejector cooling system is connected in parallel with an inverter-type air conditioner. In cloudy or variable weather, the performance of the ECS will always be at off-design conditions and the cooling capability of the ECS can easily be lost completely in cloudy or variable weather. A feedback tracking control system was designed for adjusting the evaporator temperature which may vary with solar radiation intensity. Field test results show that the regulation of the expansion valve is satisfactory and the ECS works properly. The A/C input power reduction can still be achieved at low solar radiation periods while the ejector is working at off-design condition. The reduction of input power of A/C is around 50% at low solar radiation periods due to the cooling performance of ECS. The field test of SACH-2 at different weathers in the present study has verified the feasibility of optimal performance control of SACH-2 to keep the ECS working at off-design double-choking condition by regulating the evaporator temperature. The feedback tracking control system is satisfactory. SACH-2 has been tested over 6 months from 2009/9/7 to 2010/3/20. The daily energy saving is 30% - 82%. The overall energy saving for the test periods is 52%.