brucedp5 via EV wrote:
http://www.hybridcars.com/wp-content/uploads/2015/11/Slide11.jpg (schematic) Tesla patent shows waste heat from the drive motor and electronics being used to heat the cabin
I did this way back in the 1970's. There should be a description of my system on the EVDL archives. The 1970's CitiCar also used waste heat from the motor for the windshield defroster.
The result? As a practical matter, there is so little waste heat from an EV's motor and controller that it's hardly worth the bother. If the car takes 10kw to cruise down the road, and its motor is 90% efficient, you only have 1kw of waste heat. And, that's low-quality heat... the temperature is only a little above the outside ambient.
I found it was better to use the mass of the batteries as a "heat flywheel". During charging, warm the batteries with heaters and the waste heat from charging. During driving, transfer this heat to the cabin. That cools the batteries; but they are so massive that they don't lose enough temperature to matter in (say) a 1-hour commute to work.
My EV had 14 golf cart batteries (1000 lbs) in a 2" styrafoam box. Air ducts let me circulate air through the battery box, then a cabin heater, into the cabin, and then back into the battery box. The motor could also be ducted in, but the smell produced by the brushes was annoying, and it didn't add enough heat to bother with.
The article also confuses the peak load needed to warm up a cold car (6kw) with the much lower average load needed to hold it at temperature (1-2kw). Since an EV would normally be plugged in when parked to recharge, it makes more sense to pre-heat the car with AC power, while it is still plugged in. Then you only need 1-2kw to hold it at temperature while driving.
Another thing: We've learned to insulate our homes, and plug leaks to keep down the outrageous heating and cooling costs. But cars still have virtually no insulation, and leak air like a sieve. It takes more power to heat/cool a normal car than for a small house! This was tolerable with ICEs, where you had vast amounts of "free" waste heat and huge excesses of horsepower to run air conditioners. But so far, the auto company's EVs are built the same way... no insulation, lots of air leaks.
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