抄録
A desiccant evaporative cooling consists of a honeycomb rotary dehumidifier, a sensitive heat exchanger and water spray evaporative cooler. Especially, solar assisted one is quite attractive considering various environmental problems caused by conventional electricity driven air conditioners. Unfortunately, the cooling performance is strongly influenced by solar irradiation and ambient air condition. This study aimed to clarify its actual performance and energy efficiency in Japanese summer condition. The process performance has been examined by means of temperature decrease between outside air and supply air, and COPs (COP value basing on solar irradiation). Stable solar irradiation at a clear sky gave the desiccant cooling process a higher regeneration temperature and dehumidifying performance. Average temperature decrease and COPs in this condition were 10 °C and 0.41, respectively. Unstable solar irradiation at somewhat cloudy made the regeneration air temperature lower resulting a poor dehumidifying performance. However, decreasing the cooling performance was comparatively small due to buffering effect by thermal storage in the circulating water. At higher humidity condition, the amount of dehumidified water became higher than that dehumidified at low humidity condition due to increasing relative humidity of outside air or effective adsorption capacity of the desiccant rotor. However, temperature decrease in this condition was just 6.9 °C. This behavior is mainly due to humidity increase and simultaneous temperature rise at the dehumidified air. In this situation, an effective evaporation in the following water spray evaporative cooler also does not occur. This study tries to make clear these complicated relationships between solar irradiation, process configuration and cooling performance.
