The 1-D analysis of cool down simulation of vehicle HVAC system

Abstract

In this paper, a detailed combined 1D model of Heating, Ventilation and Air Conditioning systems of a vehicle were developed by using the LMS Imagine Lab Amesim software package. The numerical simulations were considered for soaking and cool down analysis under different environmental conditions. The thermal performance of different refrigerants as R-134a and R-1234yf were evaluated in terms of thermal performance and energy consumption. According to the soaking simulation results, the cabin air temperature values ranged from 49°C to 57°C in general. The maximum increase in cabin air temperature value was about 22°C obtained for 1000 15 W/m 2 solar load. The total time until reaching the steady-state conditions for a target temperature value (23.5°C) was different for all simulations. The total time was calculated as 910 seconds for 1000 W/m 2 solar load by using R134a refrigerant loop. The results also showed that although the thermal performance of R-134a was slightly better, R-1234yf can be used due to its environmental properties with acceptable performance. The calculated COP values during cooldown analysis were ranged from 1.71 to 4.52 in general. The minimum value was obtained for the cases which had a maximum solar load and higher cabin interior temperature values. The calculated temperature data for soaking and cool down analysis were in good agreement with the reference data presented in this study. These numerical results are very important for reducing the thermal load of the vehicle cabin considering energy consumption of the HVAC system for different thermal conditions.

The Impact of HVAC on the Development of Autonomous and Electric Vehicle Concepts

“…Sevilgen et al [30] present an HVAC and cabin model in AMESim, focusing on the analysis cooling and heating process of the passenger compartment. In addition, the paper deals with the COP calculation of the two refrigerants, R134a and R1234yf, with the former getting a slightly better result.…”