Experimental investigation on a desiccant air dehumidifier constructed from a water-to-air heat exchanger

摘要

Air —conditioning has penetrated to a large extent in the building sector in Thailand. Latent load constitutes over two third of the cooling load of ventilation and is a large component of the cooling load of a building. This paper presents experimental results on a desiccant dehumidifier constructed from a water-to-air heat exchanger. The desiccant was regenerated by hot water through a conduction heat transfer mechanism. Although hot water was produced by electric heater in the experiment, the premise was that it could be produced by solar water heater. The system was installed in Bangkhuntian Campus of KMUTT and silica gel was used as a desiccant coated on the heat exchanger. The influence of operation parameters including cycle time, inlet air humidity, inlet air velocity, cold water temperature and hot water temperature on its performance was investigated. The performance parameters include moisture adsorption in dehumidification (Δd_(DE)), moisture desorption in regeneration (Δd_(RE)), and thermal coefficient of performance (COP_(th)) were also investigated. The results indicate that regeneration temperature are crucial that affect performance of system and the humidity ratio can be reduced by 4.5 g_w/kg_(da) equivalent to 20% relative humidity reduction under low air velocity with COP_(th) of 0.5.