Computer Simulation of the Performance of An Open Solar Assisted Desiccant Cooling System
Keywords:
Cooling Systems, Desiccant Dehumidifier, Solar EnergyAbstract
The performance characteristics of an open-cycle solar assisted desiccant cooling system were evaluated using computer simulation. A computer program was built and developed to simulate the effect of various design and operating conditions on the performance of the individual components making up the simulated system. They include a V-corrugated plate type solar air heater, a rotary silica gel desiccant dehumidifier, a sensible cooler and an evaporative cooler. The overall system performance was evaluated in terms of several parameters including the supply air temperature, the sensible cooling capacity and the coefficient of performance of the system. The effect of operating parameters such as the outdoor air temperature, outdoor moisture content, regeneration temperature, dehumidifier efficiencies, sensible cooler effectiveness and evaporative cooler effectiveness was incorporated in the analysis. Actual hourly weather data for Benghazi on selected clear summer days were used to assess the system performance during the day. The simulation was accomplished with a direct supply of hot air, from the solar air heater, for regenerating the dehumidifier bed. The performance of the solar air heater and the desiccant dehumidifier was first simulated independently to assess their compatibility when used in the system. Simulation results of the overall system performance showed that the heat exchanger effectiveness, evaporative cooler effectiveness and ambient conditions have the major influence on the system performance. Whereas, the influence of dehumidifier performance and regeneration temperature on the system performance was less pronounced. It was found that the simulated system can generate a cool supply of air at acceptable comfort conditions for most hours of typical clear summer days under the local weather conditions of Benghazi. The supply air temperature obtained from the system was found to be nearly constant during the selected days and at an average value for Benghazi of 18°C.
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