Application Potential of Solar Adsorption Refrigeration for High Temperature Cooling in Building

In the subtropical and modern Hong Kong, provision of air-conditioning becomes a must in buildings. However, buildings account for 88% among various end uses of electricity, and air-conditioning takes half of electricity consumption. The trend of climate change and global warming should be alleviated or even retarded by minimizing the role of fossil fuels in energy supply and maximizing the use of renewable energy. Solar energy is abundant, it is able to be applied in heat-driven refrigeration, which makes use of the principle of absorption, adsorption or desiccant cycle to provide the cooling effect. It is naturally to think about how to harness the solar energy effectively for powering up the heat-driven refrigeration. Due to the intermittent nature of solar irradiation, it is necessary to involve auxiliary heating as backup by using electricity or gas (fossil fuels inevitably). In a conventional air-conditioning design, chilled water is commonly supplied at low temperature of 5–7° C. If this cooling requirement can be elevated, it would be more feasible to adopt solar refrigeration and minimize auxiliary heating. In fact, solar refrigeration is more suitable for high temperature cooling, by providing 15–18°C chilled water instead. In such provision, conventional air handling equipment may not be suitable. But radiant ceiling cooling is a feasible alternative, in which the supply air would be provided at 19–22°C and mainly used to handle the space sensible load, which accounts for the major part of total cooling load. In this study, the performance of different kinds of radiant ceiling cooling equipment served by adsorption refrigeration would be evaluated, so that the application potential of solar adsorption refrigeration for high temperature cooling in Hong Kong could be assured. This study would be conducted by means of plant and energy simulation. The outcomes of this study would be a good foundation to attract GRF or other research grants in the fields of renewable energy and HVAC (heating, ventilating and air-conditioning).