Geothermal energy application for greenhouse microclimate management: A review

Greenhouses offer an effective approach to enhance food production by extending growing seasons and optimizing plant conditions, yet their dependency on fossil fuels presents sustainability challenges. Geothermal energy provides a viable alternative for greenhouse climate control, with technologies utilizing both shallow and deep-ground resources to meet heating and cooling demands sustainably. This study comprehensively explores the applications and benefits of geothermal energy application in greenhouse climate management. It has been observed that deep geothermal sources present an efficient and eco-friendly solution, reducing fuel costs by up to 80%. Shallow systems, such as Earth-to-Air Heat Exchangers (EAHE), efficiently regulate temperatures in moderate climates while consuming only 8%-20% of the supplied thermal energy. Integrating EAHE with solar PV systems has shown potential for near self-sufficiency. For high-tech greenhouses, Ground Source Heat Pumps (GSHPs) achieve substantial energy savings (21%-40%) over traditional systems and reduce CO2 emissions by up to 50%. However, challenges persist, particularly with high capital cost and ground thermal imbalance. Finally, this study identifies key areas for future research, addressing these challenges to further geothermal technology development and close existing knowledge gaps, advancing sustainable greenhouse practices worldwide.