Newb Asks: Why don't we rely on the component coolant for heat?

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Gregski
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Newb Asks: Why don't we rely on the component coolant for heat?

Post by Gregski »

to be honest this question was posed by one of my tens of readers on my My Dusty 71 GMCe Electruck build thread over on the 67-72 Chevy Trucks dot com FORUM but please no need to look, I'm just being honest

[ok I'll wait till you come back]

so the question was "I bet you could use the heat generated by your transmission and its cooler lines to send heated coolant to the heater core without too much difficulty?" which I would like to extend to the liquid cooled components such as our Inverters, onboard battery chargers, dc-dc converters, etc why can't we harness that heat and route it through a traditional heater core element mounted in the cabin with a blower fan? Is it that there is just not enough of it? heat that is

please and thank you,
g
head_left.jpg

just a sample pic of some equipment pointing out the coolant passages
IMG_9308 labeled.jpg

where the charger and converter dwell inside a second gen Voltaire (ha ha, see what I did there?)
trunk.PNG

just a dime a dozen cabin heater core
heater core.jpg
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arber333
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by arber333 »

Gregski wrote: Fri Mar 18, 2022 10:41 am so the question was "I bet you could use the heat generated by your transmission and its cooler lines to send heated coolant to the heater core without too much difficulty?" which I would like to extend to the liquid cooled components such as our Inverters, onboard battery chargers, dc-dc converters, etc why can't we harness that heat and route it through a traditional heater core element mounted in the cabin with a blower fan? Is it that there is just not enough of it? heat that is
Yeah... i tried that as well... and failed miserably.
Coolant gets warm true, but there is no kW in that heat. As soon as you apply any load to it it just goes cold. The same is true for the motor. No matter how you torture it it will not give out enough heat for raising temperature in the cabin.
What you would want is cooling system which would be connected to AC compressor so it would pull out heat from the motor and provide heat for the cabin without freezing over. But in the meantime i used Webasto diesel heater for high winter and Outlander electric heater for in between...
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mjc506
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by mjc506 »

These electric drivetrains are just too efficient! If only we had a propulsion technology that dumped the majority of its energy source into heat rather than motion :-)

A few cars use a heatpump (reversible AC) to heat the cabin, but that most OEMs just use electric heaters suggests that the added efficiency isn't worth the added cost.
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Gregski
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by Gregski »

mjc506 wrote: Fri Mar 18, 2022 1:37 pm These electric drivetrains are just too efficient! If only we had a propulsion technology that dumped the majority of its energy source into heat rather than motion :-)
lOl right?! I'm thinkin skip the middle man and lets proper ourselves to steam power, sky's the limit folks

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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by johu »

:D

I also tried this in Touran and noticed on the highway it provided some temperature when the front radiator was bypassed and the motor isolated rock wool. For city driving I actually dumped 300A into the motor at standstill (pure d-current, no torque) for additional heat. Never very good.

Next I added a roughly 1kW PTC element inside the cabin but that isn't exactly ferocious either.

Then I split up the two coolant circuits and added a 2 kW pre-heater. That finally generated some warm air. Takes a while, doesn't make it super cozy but I'm ok with it.

Finally I added seat heaters which only draw 30-70W as opposed to the 2000W of the heater and now I usually just drive with that to conserve energy. Gloves recommended :)
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janosch
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by janosch »

Liquid battery cooling & rapid charging I could see work:
  1. If you have 200kg+ of material that are 50deg after a rapid charge session or two, cooling them down again should produce nice warm air for the passengers?
  2. If you are not rapid charging but the batteries are full, use an electric element.
  3. If your batteries are cold & empty you are out of luck, but then you should be on your way to a charger anyway.

Is there an error in my thinking? What does Tesla do?
You should always be in one of these three states, 3) is rubbish, but 1) & 2) whack the heater on.
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by johu »

To my knowledge Tesla goes all in with Octavalve. So they scavenge heat from components, if needed go via heatpump. Also they use the motors to heat the batteries to prepare for supercharging.
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celeron55
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Re: Newb Asks: Why don't we rely on the component coolant for heat?

Post by celeron55 »

The problem is not only the low power but the low temperature. You don't get very warm air by blowing it through a 40°C radiator. You need a heat pump, and then the power becomes the problem. Tesla uses a heat pump to scavenge heat from the components, but they are able to generate more heat by using the motors as heaters. And they also have half a kilowatt worth of computing on board in the same loop which helps. And they of course have a big radiator as well, to harvest heat from the outside air, or when not heating the cabin, getting rid of heat.
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