Novel closed-system GH for irrigation and drinking needs in isolated regions

This study provides a theoretical evaluation of a closed-system greenhouse (GH) configuration, referred to as GHHD-SS. The innovation of the system lies in its sustainable integration of dual solar stills with reflectors and a two-stage humidification–dehumidification (HDH) unit, designed to supply both irrigation and potable water in remote arid regions. Within this configuration, a solar heater is employed to preheat air and water, which are continuously recirculated through the system to enhance thermal energy recovery and minimize losses. The system was modeled using the finite difference method under quasi–steady-state assumptions. Performance was evaluated by examining critical parameters, including the feed water flow rate within the humidifiers, the cooling water flow rate, the air flow rate, and the inlet temperature of the cooling water. A techno-economic assessment validated the system’s practicality, reporting a peak daily freshwater production of 18.19 L while sustaining optimal GH microclimate conditions. The humidification process achieved an efficiency of 93.9%, with both feed water and air flow rates identified as major factors influencing system performance and overall cost-effectiveness. The GHHD-SS system achieves a thermal efficiency of approximately 49.91%, with the unit cost of produced potable water estimated at 0.011 $/L and a specific energy consumption of 3.96 kWh/L. The results show that GHHD-SS produces water at a competitive cost, with good efficiency and economic feasibility compared to similar solar-assisted or thermal desalination methods.