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Discussion Starter · #1 ·
What HVAC systems are being used for DIY EVs?

I've reviewed what I can find but the results have been more abstract instead of pointing to what exactly is used. Also, searching while using 'AC' turns up more about motors than anything so it's been difficult.

I have an old Jeep that I will eventually convert but not right away. In the meantime, I need to add heat and AC. I'd like to add an EV system instead of conventional so it's ready to go for the future. Is their a system that runs off of 12v DC?
 

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An Air Conditioner is just a mechanical device that compresses air, and then the supporting system of pipes and valves and radiators.

The compressor pump works like most pumps, you power it by turning a shaft and a piston moves up and down (or whatever compressor type).

In a normal car, the AC input shaft is driven by a belt from the engine or some other mechanical means.

So, any AC from a normal car could just be repurposed by finding a different way of turning its input shaft. You could do this off an accessory belt, but generally no one does that. On an EV you just add a second motor, suitably sized and spun at the correct rate, and use that to power the pump.

A few ICE cars use this setup already.

There's a little more complexity to it than that, but, the gist of it is "Find an alternative way to spin a shaft".
 

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An Air Conditioner is just a mechanical device that compresses air, and then the supporting system of pipes and valves and radiators.
Not quite: it compresses and pumps a refrigerant (not air), traditionally chlorofluorocarbons but now other compounds.

The compressor pump works like most pumps, you power it by turning a shaft and a piston moves up and down (or whatever compressor type).

In a normal car, the AC input shaft is driven by a belt from the engine or some other mechanical means.

So, any AC from a normal car could just be repurposed by finding a different way of turning its input shaft. You could do this off an accessory belt, but generally no one does that. On an EV you just add a second motor, suitably sized and spun at the correct rate, and use that to power the pump.

A few ICE cars use this setup already.

There's a little more complexity to it than that, but, the gist of it is "Find an alternative way to spin a shaft".
I agree, but production EVs and hybrids use a compressor with an integrated motor - just like a home air conditioner - to eliminate unnecessary mechanical complexity.

So the reasonable options include:
  • keep the car's original air conditioning system, including the compressor, but add an electric motor to run the compressor
  • replace the car's original compressor with one from a hybrid or EV which has an integrated electric motor
  • if the car didn't have air conditioning, use a complete system from a hybrid or EV, or a complete electrically-powered system sold as an aftermarket product
 

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Discussion Starter · #4 · (Edited)
An Air Conditioner is just a mechanical device
As a mechanical engineer, I know how AC's work so that's not what I was asking. I have been trying to find out what system EVs typically use since ICE's constantly run and the compressor is integrated with the serpentine belt.

I agree, but production EVs and hybrids use a compressor with an integrated motor - just like a home air conditioner - to eliminate unnecessary mechanical complexity.

So the reasonable options include:
  • keep the car's original air conditioning system, including the compressor, but add an electric motor to run the compressor
  • replace the car's original compressor with one from a hybrid or EV which has an integrated electric motor
I don't want to use an R12 system from an old Jeep so I'm looking to modernize it.

On the Jeep, the AC and heater are two different blowers/systems so I want to integrate this into a single modern unit.

[*]if the car didn't have air conditioning, use a complete system from a hybrid or EV, or a complete electrically-powered system sold as an aftermarket product
This is what I can't find. Searches have not produced results so I thought I'd post on here to see what you guys have done? What brand and model? What configuration? Packaged unit like a window AC or separate components like a split air DX system?
 

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Toyota and Lexus switched to the Denso ES-series compressors to allow HVAC to work without a running engine.

A traditional compressor is cylindrical, with "in" (low pressure) and "out" (high pressure) pipes, and a pulley at one end. The high-pressure end of the cylinder may have a removable cap.

The Denso ES is cylindrical, but with a cuboid extension on the side for the electronics. A high-voltage cable and a low voltage multi-core cable plug into the cuboid. The high pressure pipe connects to a port on the cap-end. The low pressure pipe connects at the other end, as these compressors use a non-conductive oil to lubricate the internals, and the refrigerant flows through the motor to cool it. The motor is an IPM, a type of brushless permanent magnet motor where the magnets are embedded in the rotor rather than being on the surface.

Some Teslas, the Fisker Karma and VW Touareg hybrid SUVs have also used Denso ES27 or ES34 compressors.
 

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Discussion Starter · #6 · (Edited)
Thank you Emyr, I appreciate it.

With this, I did find the following site interesting: http://www.revoltev.com/2013/08/02/the-12v-climate-cooling-solution/

I might scour the hotrod discussions and solutions on this as I'm finding out, they like to have a separate AC system from the engine to max out their HP. They may already have the solution.

My engine does have a compressor mounted but the AC system has been completely removed by POs. The engine is from a '98 Grand Cherokee so it most likely is R134a compliant which would be good. I could easily use this with a www.jeepair.com system but in an effort to hopefully EV future proof the addition, I'm thinking about the Masterflux compressors.

To mimic a higher voltage from a main battery of an EV, I wonder if I could swap out the AC compressor with a higher voltage alternator?
 

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You've got too many variables in your equation to solve it.

All the components, irrespective of voltage are the same. Instead of F-ing around with hundreds of amps to feed a 12V compressor now, use what works for the engine that's in your Jeep already -- a belt drive accessory to your engine with an electric clutch. The 12V controls can stay the same (doors, actuators, solenoids) and the biggest PITA is not the compressor, but fitting the rest of the pieces of the A/C.

So - drop the idea of futureproofing, completely, and put the A/C in from either a salvage yard Jeep, a donor, or, if you're truly insane, from a catalog or FCA's parts department.

When you convert to EV, you'll have to settle on HV system voltage to drive the compressor for the sake of efficiency, if anything else. You have no clue what that will be 48V, 96V, 144V, 400V, 800V, etc. So, yeah, go buy an x Volts compressor, then you'll be making all of your HV component and traction motor decisions, like an idiot, just to reuse that compressor.

If you want A/C put it in. IMO, there's no such thing as "futureproofing" the A/C for EV because the throwaway should be the compressor, not a battery pack, not a traction motor, not an HV to xV voltage converter.

One thing you also need to look into is how the compressor is controlled. That, in itself, can get nasty pretty quickly in a beater ICE conversion.

When you do have the HV and driveline all designed and tested, add the A/C. Pick one with an electric motor from an SUV EV/hybrid so you don't have to do any of that tonnage calculation stuff you ME's seem to enjoy doing. ick.
 

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Discussion Starter · #8 ·
Hello everyone,

Anyways, sorry this post was so long. I wanted to go into detail about my experience. I hope this has helped. If anyone is interested about this compressor, just message me for details, I think the current price is $800-900 or so including shipping here. I had to wait 2 weeks lead time and 3-4 days shipping. I'll attach a photo of it
Thanks! That's exactly what I was looking for. I'm looking into JeepAir or Vintage Air for the Heat, Cooling and Defrost. I'll look into the compressor you mentioned or something similar when needed. Great find and I appreciate you posting.
 

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For what it's worth, I bought a 360 V nominal air conditioning compressor from a seller on Alibaba, and while I've not yet set it up fully, I am impressed with it's simplicity. Like Adam said earlier, I'll use the existing A/C plumbing. as well as pressure sensors and thermostats as before, however I will also be adding a heat exchanger for cooling battery coolant. Perth summers are very hot (weeks of over 40'C maximums) so keeping the battery cool is important.

Finding room for it all will be another challenge, but that's not unique to me :)
 

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I have an older version of this EV compressor where the compressor/motor are in one package and the controller for it is another separate part, but essentially the same thing. If you do decide to go with a Netgain AC or HPEV AC system then this compressor is the perfect voltage for those setups. If you go with one of the OEM systems that are running closer to 400v then it wont work. Good luck with your project.

https://www.diyelectriccar.com/forums/showthread.php?p=1041385#post1041385
 
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