Re:BYD EV Teardown in Japan Reveals the Secret to Its Afford...
by cogman10 on Thursday October 24, 2024 @04:01PM
(#41939161)
> This would be much more effective than electric heating and likely generate less carbon emissions
Perhaps in the case of an EV using resistive heating, however, most have moved on to using heatpumps.
Heatpumps have COPs that range anywhere from 2 to 10. Which means for every 1kWh in, you get 2 to 10kWh of heat out. A resistive heater has a COP of 1.
Fossil fuel power plants operate at ~40->60% efficiency, which means that past a COP of ~2 you are going to be more efficient for heating even if your power source is directly from fossil fuels. It's sort of neat.
When talking about generation mixed grids (which most are now) the COP level needed to beat having a diesel burner for CO2 output plummets.
But one more point to consider, a modern EV needs an HVAC to ensure the proper operating temperature of a battery. The thing that killed the old Nissan Leafs was the fact that they didn't have any sort of cooling system for their batteries. Put those in hot climates and you are talking major and fast degradation.
So, it wouldn't even be (much) lighter to omit the heatpump. To convert the HVAC system for the battery into a climate system is pretty much just requires a single valve.
Perhaps in the case of an EV using resistive heating, however, most have moved on to using heatpumps.
Heatpumps have COPs that range anywhere from 2 to 10. Which means for every 1kWh in, you get 2 to 10kWh of heat out. A resistive heater has a COP of 1.
Fossil fuel power plants operate at ~40->60% efficiency, which means that past a COP of ~2 you are going to be more efficient for heating even if your power source is directly from fossil fuels. It's sort of neat.
When talking about generation mixed grids (which most are now) the COP level needed to beat having a diesel burner for CO2 output plummets.
But one more point to consider, a modern EV needs an HVAC to ensure the proper operating temperature of a battery. The thing that killed the old Nissan Leafs was the fact that they didn't have any sort of cooling system for their batteries. Put those in hot climates and you are talking major and fast degradation.
So, it wouldn't even be (much) lighter to omit the heatpump. To convert the HVAC system for the battery into a climate system is pretty much just requires a single valve.