Solar desiccant cooling system

Abstract

Rotary desiccant wheel cooling system, which combines the technologies of desiccant dehumidification and evaporative cooling, can be applied to control humidity and temperature separately. The system can adopt low grade thermal energy for regeneration, such as solar energy. Compared to conventional vapor compression cooling system, it bears following, including energy saving, being environment-friendly, comfortable, healthy, etc. So solar-driven desiccant cooling system has been credited as an alternate option against conventional cooling system, which has captured great public attention in recent years. Based on the principle of desiccant cooling system, this chapter revolves around the research progress in desiccant cooling system firstly, including studies on desiccant materials, basic desiccant cooling cycles, as well as feasibility and performance of solar desiccant cooling system. Then a two-stage rotary desiccant wheel cooling/heating system is proposed, which is made up of a 20 kW desiccant cooling system and 120 m 2 solar vacuum tube air collectors. Afterward, there is a test on the system performance in cooling and heating mode. Results show that the two-stage solar driven desiccant cooling/heating system has good performance in both summer and winter. It achieves a moisture removal of 6.68 ~ 14.43 g/kg and cooling capacity of 21.7 ~ 26.7 kW under hot and humid climate conditions while the thermal coefficient of performance (COP) reaches about 1.0. The system COP in heating cycle is about 0.45, when thermal efficiency of solar air collectors is 50%. Finally, the economic feasibility and energy saving of solar desiccant cooling system are analyzed. In comparison with conventional cooling system, solar desiccant cooling system needs to be invested more initially. However, it can achieve the reduction in operating costs and carbon dioxide (CO 2 ) emissions by 45.41% and 49%, respectively, which is crucial to the sustainable development and environmental protection.