Numerical Investigations on Heat Transfer and Flow Characteristics of Climate Control Systems in Electric Vehicles

Earth's surface temperatures would increase from 2.90 C to 3.40 C by the year 2100 due to global warming, leads to conceivable calamitous effects on human livelihoods, livestock, ecosystems and biodiversity. Overall globally several policies were made to reduce the carbon dioxide emission and other greenhouse gases. The transportation sector is one of the prominent sources of carbon dioxide emissions. On account of the significant emissions caused by conventional buses, migrating to electric buses which have zero tailpipe emissions for public transport fleets is essential. Taken into consideration of the energy density of traction batteries, and cost, energy utilized for HVAC applications should be optimized. Heat transfer and flow characteristics in the condenser and the evaporator zone of climate control system for electric buses were numerically studied and compared with experimental results. Grid independence and turbulence studies were carried out to develop the CFD methodology for this analysis. Air velocity and temperature was measured at different locations in the climate control system to calculate the flow and thermal performance. Fluid flow and heat transfer characteristics of condenser and evaporator zone were studied with different duct configurations, position of heat exchangers such as condenser and evaporator, position of the blowers and fans in the evaporator and the condenser zone to achieve optimum design. Flow uniformity in the condenser and evaporator was improved by 8 to 10 % respectively, and recirculation zones in the system were reduced significantly to achieve a maximum volumetric flow rate through blowers and fans. Keywords: Fluid flow, Heat transfer, Climate control system, Numerical method