Results in Engineering (Dec 2023)
Investigation of performance and energy cost of automobile air-conditioner using alternative refrigerants based on thermal comfort using various cooling seats
Abstract
During hot summer days, the rapid rise in temperature inside a vehicle and the direct transmission of radiant energy cause significant discomfort to drivers, and the driving distance of an electric vehicle is greatly reduced due to the operation of the air-conditioner. Therefore, it is essential to provide a thermally comfortable environment to the driver and reduce the energy consumption of air-conditioners in the EV. This study investigated the thermal comfort of the driver according to the use of a basic seat (BSS), ventilation seat (VLS), and cold-water seat (CWS) in the car cabin under summer condition. Also, based on thermal comfort, the system performance and energy cost of an automobile air-conditioner using various alternative refrigerants were analyzed and compared. As a result, when the CWS was used, the stress index of subjects was the lowest in the PPG, and the relative β/α of the subjects decreased in the EEG. In addition, the results of the subjective questionnaires and bio-signal measurement showed the most thermally comfortable when using the CWS. The COPs of the air-conditioner using R134a, R1234yf, R1234ze(E), and R152a increased by 19.3 %, 18.9 %, 19.0 %, and 19.3 %, respectively, and annual energy consumption of the air-conditioner decreased. In addition, in the five European countries, the annual electric charging costs and annual eq-CO2 emissions for using the CWS showed the most significant reduction in Germany. Therefore, it was confirmed that using CWS can provide a thermally comfortable environment for drivers inside the vehicle during summer and effectively reduce power consumption used for air conditioning in EVs.
