Thermal Model Development of a Biomass Regenerated Desiccant Supported Greenhouse Cooling for Orchid Cultivation

Abstract In this paper, a novel scheme of biomass regenerated desiccant supported greenhouse cooling with distributed fan-pad evaporative system has been proposed. The system aims to provide suitable thermal condition inside the greenhouse for cultivation of high value flowers like varieties of Orchid which require a temperature between 21 °C to 26 °C and humidity from 50 to 70% for the sub-tropical climate prvailing in the plains of India. In the proposed system two stage desiccant based cooling is used to obtain a low humidity ratio. A biomass based heating system is coupled for regeneration of the desiccant. Thermal modeling of desiccant wheel and greenhouse are done to estimate air temperature inside the greenhouse. A comparative study has been made based on estimated greenhouse air temperature with the results of the reference model available in the literature. From the performance analysis of the proposed system, it is revealed that the maximum temperature of the greenhouse air can be restricted within 25 °C and 25.8 °C for a hot and humid day prevailing in the month of July and September respectively. However the system can maintain a lower temperature of 19 °C during the morning time which is more conducive for target plantation (Orchid) in the given region.