Hybrid ground source heat pump for sustainable greenhouse climate control in hot and humid region

Greenhouses in hot and humid regions present significant challenges in maintaining optimal temperatures and humidity while minimizing energy and water usage. Traditional boiler-based heating is energy-intensive, and evaporative cooling often fails to maintain suitable conditions, especially under high humidity and peak thermal loads. This study evaluates the performance of a novel hybrid geothermal heat pump (HGSHP) system integrated with a cooling tower, specifically optimized for greenhouse operations in hot and humid climates such as Houston, Texas. The system was assessed using a dynamic model developed in TRNSYS Studio. Results showed that the HGSHP configuration reduced cooling energy consumption by up to 10.8% compared to GSHP-only systems and significantly enhanced ground thermal stability, lowering the annual ground temperature rise from 1 °C to less than 0.1 °C. The wet cooling tower effectively mitigated thermal imbalance by rejecting up to 37% of the cooling load during peak summer conditions. These findings highlight the potential of HGSHP systems to deliver efficient heating, cooling, and dehumidification with improved energy performance and long-term sustainability for greenhouse applications in hot and humid regions.