Feasibility study of using agriculture waste as desiccant for air conditioning system

This research was aimed at investigating the feasibility of using dried agricultural waste as desiccant for an open cycle air conditioning system. The natural fibers are, therefore, intended to replace chemical desiccant such as silica gel, molecular sieves etc. The investigation was limited to Coconut coir (Cocos nucifera) and Durian peels (Durio zibethinus).Experimental results confirmed that dry coconut coir and durian peel can absorb 30 g and 17 g H₂O per 100 g dry product, respectively, from air at the average condition of 32°C and 75% relative humidity. The optimum airflow rate is about 84 and 98 m³/hr-100 g dry product, respectively. Therefore, the dry coconut coir is more suitable than the dry durian peel.Comparison between the dry coconut coir and silica gel showed that the average adsorption rate of coconut coir is less than that of silica gel by about 5 g/h-100 g dry product at an airflow rate of 84 m³/h and 60 min operating time. However, it is still an interesting option to replace silica gel in open cycle air conditioning system, as the decrease of average adsorption rate is rather small.The other extremely interesting advantage of coconut coir is that during moisture absorption the heat generated during the process is less important. That means the air leaves the coconut coir bed at a lower temperature compared to that with a silica gel. Therefore, the saving of cooling energy is much more important.