On 5/26/2017 1:50 AM, brucedp5 via EV wrote:
The article has outdated information and the author does not fully
understand how the Tesla heating system works. Here is how it really works:
How (Tesla) EV air conditioning works> (also minimizes pack-cell temp
Most folks don't understand how "reverse cycle" A/C works. (Also called
a "heat pump".) Many modern EV's have a heat pump arrangement in
addition to a simple resistive type heater. The heat pump is 3 or 4
times as efficient as a resistive heater in all but the coldest outside
temperatures, resulting in far less energy use for the same cabin heat.
The resistive heater is only used below about -15 Celsius outside
temperature, when the heat pump becomes ineffective.
Basically, with an arrangement of valves, they run the A/C system
backwards. It is like taking out your window A/C unit and putting it in
backwards. It absorbs heat from the cooler outside air and "squeezes" it
out to the warmer inside air. Thus the term "heat pump" as you are
"pumping" heat "up hill". One third to one fourth the energy use than an
equivalent resistive heater.
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