A Study on the Effect of Solar Fraction on the Environmental Performance of Solar Air-Conditioning by an Adsorption Chiller

Solar air-conditioning (AC) is a sustainable air-conditioning system but a back-up heater is needed because a solar AC has intermittent output. This study presents the effect of ratio of heat delivered by solar to the total heat delivered to an adsorption chiller (solar fraction) on the environmental performance of a solar AC system. This AC system need covers cooling demand for an office building in Malaysia. Cooling demand of the building was simulated using well-known building energy analysis software, Equest. Flat-plate collectors and an adsorption chiller were the main component of the solar AC system. Flat-plate collecters were simulated using another software, Watsun, and the adsorption chiller was based on the author simulation model that is comparable with other studies. Environmental performance was analyzed by emission ratio of a boiler and power plants. Solar fraction of 0.33, 0.74 and 0.98 were studied. It was found that solar AC by an adsorption chiller can cover the cooling demand of the office building throughout the year. It was also found that a gas fired boiler is a better auxiliary heater than an electric heater because of the direct conversion of heat from fuel. Less emissions is emited at higher SF compared to conventional AC for all cases of back-up heater. A solar AC must has solar fraction higher than 74% to ensure it emits less emissions than a conventional AC system