High Performance HVAC Component Development for EV Using 1-D System Simulation

The current paper focuses on the compact HVAC component development for electric passenger vehicles running in countries where the external ambient conditions are harsh. Various previous studies have shown that the energy required for HVAC system alone is about 12-15 percent of the overall vehicle energy demands. Due to very high thermal loads, the Electric Vehicles operating in such countries will obviously fall under the higher HVAC energy consumption band. In addition to the energy demand, the cooling requirements like shorter pull-down time adds further challenges to the HVAC design. Another major challenge being faced by the EV manufacturers is the concerns due to range which has resulted in compact vehicles having less space for HVAC and other subsystem components.

The current paper proposes an approach for replacing the conventional air-cooled condenser by liquid-cooled condenser. A liquid-cooled condenser will be much more compact than a conventional condenser. In addition, liquid-cooled condenser will be more efficient and will lead to the design OR selection of other efficient HVAC components like compressor. This high-efficient HVAC system will be much more responsive and will have better pulldown performance. Simulation driven design is the best way to develop efficient HVAC components during concept development stage. The current paper uses 1D system simulation tool namely GT-Suite to study the HVAC component performance and sizing along with the overall thermal energy management. To get confidence in the simulation results, a few benchmarked and tested systems are selected from available literature and the simulation results are compared for correlation. A full thermal layout was created in GT-Suite including all the cooling subsystems. The results include various thermal parameters, pull-down performance and the energy consumed by the components when the vehicle is driven in high ambient conditions.