Design and construction of a water-glycol autonomous system which controls the evaporating temperature of a transcritical CO2 refrigeration cycle including thermoelectric subcooling

Abstract

Recent regulations on refrigeration fluids with a high GWP value are forcing researchers to find new sustainable refrigerants. The CO2 seems to be the perfect candidate due to its neglectable environmental impact and its harmless properties to human beings. However, the working conditions at the transcritical region, caused by high ambient temperatures, decreases considerably the COP of the system. Therefore, new configurations efficiently working with the CO2 are required. The ITF research group from the UPNA has analysed the implementation of an innovative technology in order to optimize a CO2 refrigeration cycle: thermoelectric subcooling. They have theoretically proved that the efficiency increases and nowadays are constructing a prototype which includes the vapour compression refrigeration cycle and the TESC in order to carry out tests and optimize the cycle. To do this, it is completely necessary to simulate the thermal loads of the cycle with an auxiliary circuit. The objective of this project is design and construct this auxiliary circuit and justify the selection of each element constituting it.