The current electric refrigeration and air condition systems are major causes for ozone depletion and global warming. These systems consume large percent of the worldwide gross production of electricity (around 17%). Therefore, developing new refrigeration systems that are able to work using renewable sources (solar, geothermal, etc) and waste heat sources is necessary to address these problems. In this paper, an experimental investigation and heat transfer analysis of an innovative thermal-mechanical refrigeration (TMR) system are presented. The TMR system replaces the electric compressor of the conventional refrigeration systems with an expander-compressor unit (ECU). The ECU can be driven by ultra-low temperature heat sources, has simple configuration, and high flexibility for the operating conditions. A hybrid electric-compressor and ECU refrigeration experimental setup was built to investigate the performance of the ECU and compare it to the electric compressor with R134a as the working fluid. The effect of the major operating parameters (condenser and evaporator pressures and temperatures) on the performance of the electric and TMR systems are investigated and analyzed. The results show that a maximum COP is obtained at refrigerant mass of 30g in electric mode and at refrigerant mass of 60g in ECU mode. A comparison of the TMR to other existing thermal refrigeration systems showed that most of these systems have more complex configurations, lower COP, and higher capital costs.

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