Optimized operation of a solar hybrid desiccant - displacement ventilation combined with personalized evaporative cooler

Abstract

The study investigates by modeling and experimentation the performance of a hybrid air conditioning system that operates in humid climate and conditions the room by displacement ventilation (DV) aided with personalized evaporative cooler (PEC). The hybrid system includes a cooling coil and a solid desiccant (SD) dehumidification system regenerated using parabolic solar concentrator system. Predictive component models of the conditioned space, the solid desiccant, the solar concentrator system, and the PEC were developed and used for prediction of associated energy consumption during transient response while utilizing an optimized control strategy. The control strategy seeks optimal values of supply air flow rate an temperature and the desiccant regeneration temperature that will lead to minimum energy consumption for both cases when the PEC is used and without the use of the PEC while meeting space load, indoor air quality and thermal comfort requirements for East Mediterranean coastal climate during the cooling season. Energy consumption was calculated for the optimized solution that used genetic algorithms and the integrated DV-SD-PEC models. The results agreed well with experimental data obtained from tests on a DV climatic chamber. In addition, votes of comfort recorded by participants in the experiment using PEC were very similar to predicted comfort. The optimized hybrid system performance was applied to a typical office space of area of 64 m². The operation of the hybrid system with personalized evaporative cooler(s) resulted in a higher supply air temperature. The increment in supply air temperature is 1.1⁰C when PEC is used compared to case without PEC. This increase in temperature showed an energy saving of 13.5percent is achieved for the PEC aided hybrid system.