Experimental Investigation on the Effect of HVAC Power Consumption in Electric Vehicle Integrated with Thin Film Solar PV Panels

Air conditioning systems are one of the significant auxiliary loads on the vehicle powertrain. In an Electric Vehicle (EV) where the available energy is limited, it becomes crucial to optimize the overall energy consumption of the auxiliary loads. The major power consuming components in an automotive HVAC system (Heating, Ventilation and Air Conditioning) are: Compressor, Cabin blower, Condenser cooling fan and the Control devices. Significant progress is already made in enhancing the energy efficiency of the above-mentioned power consuming components part of vehicle HVAC system. Alternate energy sources are being explored recently, to reduce the energy demand from vehicle. One such proposal is to harness the abundant solar energy available, through solar panels and consume this energy to supplement the power required for HVAC system components. Solar panels convert solar energy to electrical energy by the principle of the photovoltaic effect. A thin-film solar cell is a second-generation solar cell that is made by depositing one or more thin layers, or thin film (TF) of photovoltaic material on a substrate, such as glass, plastic or metal. Thin film solar panels can be easily adapted to suit the curvatures on the vehicle exterior surfaces and can be installed accordingly. In this study, a 48V EV is being utilized to understand the power that can be harnessed from thin film PV panels installed on its roof and the extent to which this power can be utilized to meet the power demand of its air conditioning system. Initially, baseline tests are conducted in the vehicle without solar panels at different ambient conditions. The measurements help us to understand the power demands from the different components of the system at various loading conditions. A MATLAB model is developed, and simulations are undertaken for generating the power output based on hourly changes in temperature and solar load (only direct radiation considered, and diffused radiation ignored), for different seasons of the year. The thin film PV panels are installed on the roof of the EV and integrated to the battery through MPPT controller. Experimental investigations are conducted on the vehicle after installing the PV panels. Studies are conducted both in static conditions as well as in vehicle dynamic conditions to understand the extent to which the solar energy can be harnessed to supplement the air conditioning system power requirement.