Study the Performance of a Novel Desiccant Heat Exchanger

Abstract

Conserving energy and reducing emissions has become a global consensus. However, most air conditioning systems are highly energy-consuming, affecting global warming and the ozone layer because they use chlorine and fluorine refrigerating fluids. Evaporative cooling systems are one of the most important environmentally friendly air conditioning systems with low energy consumption. However, their performance is negatively affected by the high humidity of the inlet air. One of the solutions to control the relative humidity of the inlet air is using desiccant material. In this paper, a silica gel-coated heat exchanger was designed and constructed as a dehumidifying unit. The effect of airflow rate, hot water flow rate, cold water flow rate, and regeneration temperature on the system's performance has been studied. It was found that increasing the hot water flow rate improves the removing moisture from the desiccant. However, increasing the hot water flow rate has a negative effect on the thermal performance of the heat exchanger. The effectiveness of the heat exchanger was 53% in the regeneration phase and 52% in the cooling phase for the outside air temperature of 40 ºC, W=20 g/kg, and an airflow rate of 0.48 m³/s. From the results shown above, it was noticed that the system could work efficiently in hot and high humidity climates and be used in Iraqi weather.