Investigation and assessment of the optimum conditions of solar heat source hybrid desiccant cooling system under different modes

Abstract

In this study, the hybrid desiccant cooling system (HDCS) with solar heat source is experimentally studied, and various alternative methods are suggested for the problem of the cooling system which is of concern due to the characteristics of solar power, empirical experiments and the applicability of solar heat sources to HDCS. The results of empirical experiment are analyzed through daily data, while cooling temperature is set to Tset = 22 °C (setting temperature) under the conditions of TOA = 32 °C (outdoor air temperature), RHOA = 45 % (outdoor air relative humidity), Tst = 70–80 °C (storage top temperature), Treg = 70 °C (regeneration temperature), dehumidification = 4.5 g/kg, COPelec = 4.8, and COPth = 2–4. When Tst is higher than 85 °C, it may damage the system due to material characteristics of desiccant rotor. Therefore, flow rate of the load-side pipe is lowered by adding a bypass pipe to load-side pipe, and OA (outdoor air) of 60–70 °C suitable for regeneration of the desiccant rotor can be supplied. When the Tst is low, the Tst is increased by lowering the Treg and rather absorbing the heat of the condenser and radiating the heat in the heat storage tank. If the Tst is higher than 85 °C but no separate action can be taken on the load side, a radiator can be installed at the solar system to control the temperature of storage tank. If hot water supply is controlled according to the temperature of storage tank, the solar heat source can be stably applied to the HDCS.