Thermodynamics and economic analysis of a two-stage desiccant cooling (TSDC) system based on biomass heating used for greenhouse application

This paper proposes a novel scheme of biomass-regenerated two-stage desiccant-supported greenhouse cooling in tropical and subtropical regions. The system’s goal is to provide the ideal thermal environment inside a greenhouse for the growth of different kinds of Orchids. Two-stage desiccant-based cooling is used in the proposed system to obtain a low humidity ratio inside the greenhouse. The desiccant is regenerated using a biomass-based heating system. The first law analysis and the exergy analysis of the system’s individual components have been included in the study. The results of the thermal model (greenhouse temperature) have been compared with those of a reference model study available in the literature. The mean absolute error for the humidity ratio and greenhouse air temperature is 4.3% and 4.5%, respectively. The model’s predictions are in good agreement with the results of the reference model. The performance study reveals that the maximum greenhouse air temperature can be restricted within 26 °C even during the peak sunshine hours for a typical day in May which represents the peak summer season in India. The proposed system COP_th varies from a minimum of 0.54 to a maximum of 1.02 for a typical hot and humid day of July. The proposed system can exhibit a maximum exergy efficiency of 33% at 6 AM for a representative day in July. The maximum exergy destruction occurs at the DW₁ (39.25%) and regeneration heater (21.69%). The payback period of the proposed system is 8.2 years, considering a 15-year life span.