OTEKON 2020, Bursa, Turkey, 6 - 07 September 2021, pp.1065-1073
Heat exchangers used on a system basis in different sectors are systems that meet the need for cooling or heating by performing heat exchange between two fluids with different temperatures, which are prevented from mixing with each other due to their general characteristics. Internal heat exchangers (IHX), one of the heat exchanger types, are effectively applied under air conditioning (HVAC) systems due to their ability to increase the efficiency of potential cooling loops, lightness and ease of packaging, which are also used in the automotive industry. The function of the component in the thermal cabin cooling cycle creates a reverse flow between the high temperature liquid coming from the condenser and the cold steam coming from the evaporator, allowing heat transfer between the fluids. In this study, firstly, a CFD model was created together with the detailed measurements of the existing IHX internal reverse flow heat exchanger in the air conditioning system in a vehicle with a 3-cylinder internal combustion engine.Steady-state, coupled energy, turbulent flow model RANS method has been used on CFD anaylsis setup. According to these parameters, system-based heat transfer - pressure drop and heat transfer performances calculations were made. In addition, CFD results and test results correlations were made with the fluid flow rates determined by considering the test conditions performed under the standards. The efficiency of the existing heat exchanger was examined as pressure loss and heat transfer at a C b bar in the low pressure gas zone and 9a C 5b+1 bar in the high pressure liquid zone. Experimental and theoretical evaluation of the heat transfer properties of the internal reverse flow heat exchanger in the duct is presented by obtaining the chemical and thermal properties of the refrigerant R1234yf, known as the air conditioning gas, under the specified boundary conditions from the moody diagram.