Researchers have been investigating solutions to improve the efficiency of the vapor compression system to overcome the challenges of switching to natural working fluids. The inclusion of a thermoelectric subcooler (TESC) in the vapor compression system is one of the state-of-the-art solutions to improve system efficiency by further subcooling theworking fluid after the condenser/gas-cooler, it also provides a dynamic control over the capacity by varying the supply current to the thermoelectric modules (TEMs) [1]. However, finding optimum operating condition of TEM and providing best capacity-efficiency relation on defined conditions is challenging [2]. Therefore, main aim of this paper is to develop and validate a numerical model of TESC and investigate potential performance improvements of proposed design. The TESC has two streams: (1) working fluid where heat is absorbing by cold surface of TEM and (2) water stream where heat is rejecting by the hot surface of TEM. Two TESC design are simulated and will be validated with different working fluid as main stream, R290 and CO2. The TESC running with R290 implemented downstream the condenser on heat pump test-rig and the TESC running with CO2 implemented downstream the gas-cooler of ejector-based refrigeration test-rig located in Silesian University of Technology, Department of Thermal Technology laboratory. A coupled model is developed and will be validated based on the experimental results. TESC was represented by three independent simulations were running simultaneously: one simulation for main stream heat exchanger and two simulations for water stream. Each simulation temperature outputs connected by a external program to generate heat flux values for TEM. The boundary conditions defined by measurement from the experimental campaign and all the thermophysical properties defined based on the polynomial functions derived from NIST database. Finally, the efficiency and validation discrepancy of the devices, will be presented during the conference. REFERENCES [1] P. Aranguren, D. Sanchez, M. Haida, J. Smolka, R. Cabello, A. Rodriguez, D. Astrain, Effect of thermoelectric subcooling on COP and energy consumption of a propane heat pump. Appl. Therm. Eng. (2024) 257: 124242. [2] D. Sanchez, P. Aranguren, A. Casi, R. Cabello, D. Astrain, Experimental enhancement of a CO2 transcritical refrigerating plant including thermoelectric subcooling. Int. J. Refrig. (2020) 120: 178–187.