Climate Heat Recovery Energy Study in Electric Vehicles

Climate control systems in Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Extended Range Electric Vehicles (EREVs) rely on electrical energy to provide cabin heating. In winter conditions, the absence of waste heat from internal combustion engines necessitates increased energy consumption for thermal comfort, which directly impacts vehicle range. Conventional HVAC systems typically operate with a mixture of cold ambient air and recirculated cabin air. However, the proportion of recirculated air is limited due to windshield fogging risks, constraining energy-saving potential. To address this, MAHLE has developed modular heat recovery technologies that utilize the thermal energy of exhaust cabin air, that would normally leave the passenger compartment through vehicle body vents, to precondition incoming fresh air, thereby reducing the heating load. These solutions are engineered for scalable integration into existing HVAC architectures, allowing adaptation to varying vehicle packaging constraints and performance requirements. The concepts are compatible with both direct and indirect refrigerant systems, including R1234yf, R744 and R290 ensuring broad applicability across future vehicle platforms. Experimental validation has been conducted at component, module and vehicle levels. Results confirm substantial heat recovery potential, leading to measurable reductions in HVAC energy demand and corresponding increases in driving range. These measures contribute to improved thermal efficiency and support the broader objectives of sustainable mobility by enhancing energy utilization and passenger comfort in electrified vehicles.