An innovative absorption refrigeration system for cooling high geothermal tunnels: Theoretical analysis and On-site testing

Addressing the thermal hazards and high temperatures encountered during the construction of high geothermal tunnels is crucial for ensuring worker safety, improving productivity, and enhancing structural integrity. To this end, this paper innovatively proposes a new method for resourcefully utilizing thermal damage and cooling high geothermal tunnels—using high-temperature tunnel water to drive an absorption refrigeration cycle that serves to cool the tunnel itself. Taking a high geothermal tunnel currently under construction in China as the background, thermodynamic models for the components of the absorption refrigeration cycle were established based on the principles of energy conservation and mass conservation through numerical simulation. Combining this with monitoring data from the tunnel, the feasibility of applying the absorption refrigeration system (ARS) to the tunnel was analyzed. Based on the analysis results, a small absorption refrigeration unit was customized for cooling tests in the tunnel’s rest room. The test results showed that, when the ambient temperature inside the tunnel was 37°C, the ARS was able to lower the rest room temperature to 25°C, meeting the relevant standards and ensuring safe and efficient construction in the high geothermal tunnel.