Geothermal Energy Technologies for Cooling and Refrigeration Systems: An Overview

Geothermal energy attracts many scientists' attention because of its availability throughout the year and its low carbon emissions, making it a suitable replacement for fossil fuels. The Earth's thermal energy can be extracted via boreholes drilled into the subsurface, and utilized as a reliable heat source for industrial, commercial, and residential applications. Geothermal energy is currently used to produce electricity, heating, and cooling through innovative technologies and routes, but its vast potential remains largely untapped. On the demand side, there are cooling technologies that are typically not associated with geothermal energy, and the application of such technologies warrants the necessity of studying geothermal refrigeration methods. In this paper, a literature review is conducted on combined cooling, heating, and power (CCHP), cogeneration, tri-generation, and poly-generation systems, wherever cooling is produced by a geothermal resource. This review article is divided into five main sections as: (1) experimental and practical studies, (2) numerical and simulation works, (3) exergy assessments, (4) optimization techniques, and (5) economic analyses. It is concluded that geothermal refrigeration could be a promising technology, specifically when it is used in multi-generation systems. Combining other energy sources with geothermal energy in refrigeration applications may offer higher energy and exergy efficiencies, as well as more cost-effective options. Among other renewable energy sources, solar energy has been studied in combination with geothermal energy, more than the others. The results, obtained in this article, are expected to help designers, researchers, and practitioners in the industry to develop more geothermal-based multi-generation systems that are efficient and sustainable.