Solar-Assisted Phase Change Material System for Efficient Cabin Heating in Electric Vehicles Under Cold Conditions

Abstract

Electric vehicles (EVs) represent a sustainable alternative to internal combustion engine vehicles; however, their limited electrochemical energy storage poses a critical challenge in cold climates, where cabin thermal conditioning can markedly diminish driving range. Conventional resistive heating systems are characterized by high energy consumption and low thermodynamic efficiency. This study introduces a solar-assisted cabin heating strategy incorporating phase change material (PCM) to address thermal management in EVs under cold ambient conditions. The system integrates a roof-mounted photovoltaic (PV) module, adaptive reflective mirrors to enhance solar irradiance capture, and a hybrid thermal storage unit comprising water and encapsulated PCM (Rubitherm RT50), which was selected due to its high latent heat capacity near the desired cabin comfort temperature, enabling efficient thermal energy storage and prolonged heat release during cold ambient conditions. Designed for the Citroen Ami electric microcar, the system operates independently of the vehicle's traction battery, ensuring sustained cabin comfort without compromising driving range. Two experimental configurations were evaluated at ambient temperatures ranging from -2 degrees C to +2 degrees C: a water-only thermal storage scenario and a water-PCM hybrid scenario. Experimental results demonstrated that PCM incorporation significantly augmented the thermal energy storage capacity and prolonged heat release duration. Relative to the water-only configuration, the PCM-enhanced system achieved a 3.1 degrees C increase in cabin air temperature and a 10 degrees C higher outlet air temperature at the conclusion of the heating cycle. This integrated system presents a promising, energy-efficient solution for preserving EV range while ensuring occupant comfort in cold weather.