The End of Traditional Vapor Compression A/C

By MACS Staff

As fossil fuel vehicles, powered Internal Combustion Engines (ICE), are replaced on dealer lots in favor of Electric Vehicles (EVs), significant changes are coming to the vehicle thermal management systems the industry has used for 70+ years. This transition will spell the end of the traditional method of heating the occupants with coolant, heated by the ICE engine, and circulated by a water pump to a heater core in the passenger compartment.

The end of vapor compression A/C systems?

But how does this lead to the end of vapor compression A/C systems? Traditional vapor compression systems have very limited capacity to create usable heat and, the loss of heat from the ICE engine must be replaced somehow in some way. I know what you are thinking, many EVs on the market today have electric compressors with vapor compression A/C systems and these vehicles still have heat for cabin comfort and thermal management of the electronics. You are correct. These EVs use Positive Temperature Coefficient (PTC) heaters in place of the ICE engine heat are inefficient and place a tremendous burden on the vehicles drive battery particularly in cold winter climates.

EV batteries function at their best when they are thermally pre-conditioned to their optimal temperature. The energy required to do this pre-conditioning has an impact on vehicle range, which, in turn, has a negative impact on the environmental benefits of EVs. In case you are unaware, EVs may have zero direct emissions but they have indirect emissions from the fuel or infrastructure required to produce the electricity. I digress…

Heat Pumps

For many years, homeowners and other industries have turned to heat pumps to provide heating and cooling with the heating supplemented in extreme cold conditions by other heat sources like PTC heaters. These heat pump systems have started making their way into some electric vehicles like the Hyundai Kona. They appear to be the future for vehicle thermal management in electric vehicles. The current automotive heat pumps from Hyundai continue to use R-1234yf as their thermal transfer fluid (refrigerant). However, research is underway to see if a different fluid may further improve the efficiency of these systems or, if modifications to the heat pump system itself, can get the desired results while continuing to use R-1234yf.

Either way, the writing appears to be on the wall as they say for traditional vapor compression systems as we transition away from ICE to EVs.

You can read more about the Hyundai Kona heat pump at: https://www.hyundaimotorgroup.com/story/CONT0000000000002995.