Thermoeconomic performance evaluation and optimization of a geothermal heat pump system for greenhouse heating in low-temperature resources

Abstract

This study presents the design and thermoeconomic performance analysis of a geothermal-assisted heat pump system for greenhouse heating in regions with low-temperature geothermal resources. The aim is to explore efficient utilization of geothermal energy as sustainable alternative to conventional greenhouse heating methods. Comprehensive thermodynamic and economic assessment were conducted based on a 50,000 m2 greenhouse simulation, utilizing geothermal fluid at 45 °C with flow rate of 50 kg/s. Results confirm technical feasibility and economic viability of the proposed system. Heat pump achieved high coefficient of performance of 4.712, demonstrating its effectiveness in harnessing geothermal energy for heating applications. The system’s exergy efficiency was calculated as 29.64 %, indicating efficient energy utilization. Total heat demand of greenhouse was determined as 5305 kW, with heat pump compressor requiring 1126 kW of electrical power. Heating cost and total investment of system were estimated as 0.004851 $/kWh and 6.469 million $, with annual operation and maintenance expenses of 246,558 $. Despite these costs, system generates annual revenue of 2.5 million $, resulting in a simple payback period of 2.5 years. These findings highlight system’s strong potential to enhance greenhouse operations’ economic and environmental sustainability, supporting broader adoption of geothermal heat pump technologies in low-temperature geothermal regions.