Biomass Regenerated Two-Stage Desiccant Cooling (TSDC) System Used for Greenhouse Farming in Hot and Humid Regions: A Seasonal Performance Study

This study represents an innovative greenhouse cooling method employing a two-stage desiccant cooling system regenerated by a biomass-based heating unit. The goal is to create a greenhouse environment suited for growing high-value flowers like Dendrobium Orchids in the subtropical climate in the plains of India. Thermal modeling of the three major units, the desiccation system, regeneration unit, and greenhouse, is carried out to estimate the air temperature inside the greenhouse. The system performance has been analyzed for the five most effective months (March, May, August, October, and December) of a calendar year representing the respective seasons (Spring, Summer, Monsoon, Autumn, and Winter) for the considered place. The proposed system can maintain the highest daily mean greenhouse temperature ranges of 21.5–26 °C during the daytime of May (summer). The system can also restrict the greenhouse temperature within prescribed ranges for the other four seasons. It is possible to reliably keep the greenhouse air’s relative humidity within the prescribed ranges of 40–70% throughout all considered seasons of a complete calendar year. The vapor pressure deficit (VPD) inside the greenhouse is about 30% lower in the summer (May) operating season than in the winter (December).