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Old 21st July 2010, 01:23 AM   #21
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Re: Electric A/C Compressor

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BTW, none of you commented on the tail lights. I got a set for my GT40.
I did....check out post #17. I think I'll get a set for my Cobra.........

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Old 21st July 2010, 10:37 AM   #22
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Re: Electric A/C Compressor

Oops. Sorry. At least two of us appreciate the finer things....
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Old 21st July 2010, 12:27 PM   #23
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Re: Electric A/C Compressor

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Oops. Sorry. At least two of us appreciate the finer things....
Great minds think alike !
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Old 21st July 2010, 08:31 PM   #24
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Re: Electric A/C Compressor

So far the only likely candidate I've found is a Sanden unit used in the late, lamented-by-some Ford Ranger EV Pickups. However, I don't yet have any technical data on it.

The Prius unit is essentially unusable for our purposes because it is designed to be highly integrated into the rest of it's own unique A/C system. It's not an electric compressor you could plug simple single-phase AC or DC of any voltage and get it to work: it needs to be sequenced by its controller.

I thought about just coupling my existing Sanden compressor to an off-the-shelf electric motor, but we're talking about a 2 to 4 HP motor here, and that would be, well, gross.

Sanden says they will make a "generic" electric compressor but offer no details on the web site.

There are some nice Panasonic units but none uses R134a refrigerant.
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Old 21st July 2010, 08:54 PM   #25
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Re: Electric A/C Compressor

why does the compressor care if it is 134a or some other freon. the compressor is just a pump. compressing the refrigerant gas . many of the older systems that were R22 can be converted to 134a it is the expansion valve that determines the refrigerant.
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Old 21st July 2010, 09:41 PM   #26
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Re: Electric A/C Compressor

I know there are some manufacturers offering 12V electric power steering systems...would it be possible to use the electric motors (or, perhaps, the pumps from those systems) in some manner to make this possible? I have no idea what level of power the motors would be required to produce to make power steering possible, but I do know that many hydraulic systems operate at high pressures.

Just an idea.....of course, I'm no engineer, so if it were possible I'd suppose one of them would have thought of it already, so the idea is probably just a ......but, what do y'all think?

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Old 22nd July 2010, 10:18 AM   #27
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Re: Electric A/C Compressor

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Originally Posted by Lynn Erickson View Post
why does the compressor care if it is 134a or some other freon. the compressor is just a pump. compressing the refrigerant gas . many of the older systems that were R22 can be converted to 134a it is the expansion valve that determines the refrigerant.
Chemistry, lubricant compatibility, seal material? Maybe it doesn't, although the Panasonic site specifically lists the corresponding refrigerant (R22 or R410A). BTW, re: conversion do you mean R12, not R22? AFAIK R22 is normally used in building A/C. If R22 is in fact easily converted to R134A we have a solution.

See for example P Series Compressors for Air Conditioning - Panasonic

Later note: after some research it's starting to come back to me now... R134A and R22 are HFCs or HCFCs, not CFCs like R12. The former in principle use different hoses and seals because (roughly speaking) the molecules are smaller and can migrate into or through the CFC hose material. However, it appears that in practice R22 can be substituted for R12 or R134a although it's probably illegal to do so. Vice versa is presumably OK. I'll keep working on this.... Obviously the cool thing to do (so to speak) would be to us either R134a or R410A since those are both current, legal refrigerants. Just need to figure out the compatibility issues with the rest of the system (seals, hoses, pressures, lubricants).

Later Later note: Bingo! It's been done. See

http://www.evdrive.com/BMW_project/AirConditioning.html

Last edited by awatkins; 22nd July 2010 at 11:05 AM.
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Old 22nd July 2010, 06:59 PM   #28
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Re: Electric A/C Compressor

Have done no research into this, but what about solid state refrigeration? I know it exists, but don't know if there are any units large enough to cool a car's cabin. I've seen units (like "powered coolers") that run on 12V and as far as size, how about the size of a steno pad? And, not tied to the engine, can be mounted anywhere.

I don't think it cools the given volume down very quickly, though, so may not be feasible even if you can find a unit large enough to cool a car cabin.

May be completely an unuseable idea, but I thought I'd throw it out there for discussion.

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Old 23rd July 2010, 04:17 AM   #29
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Re: Electric A/C Compressor

Peltier blocks?

But they do not seem to me big enough for aircon

Thermo Electric Modules, Peltier Elements, TE Modules, Heat Pump

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Old 23rd July 2010, 08:12 AM   #30
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Re: Electric A/C Compressor

In Australia you cannot now sell package units with R12 or R22, and you cannot manufacture these refrigerants. R134a is a replacement for R12 (the refrigerant formerly used in domestic and automotive systems), subject to seals and other compnents being suitable, but is not a substitute for R22. We use R407c, also R410a. I'm sure friends of mine have had 4x4's with separate rear passenger electric motor driven A/C systems. A luxury version Landrover was one, if my memory is correct.
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Old 23rd July 2010, 12:04 PM   #31
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Re: Electric A/C Compressor

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Originally Posted by awatkins View Post
Later Later note: Bingo! It's been done. See

Performance EV conversion - Project work - Air Conditioning

OK, this looks promising. This project used a Masterflux, model Sierra 06-0982Y3 unit and its controller available from Masterflux's retailer Revolt (http://www.revoltcustomelectric.com/...cessories.html) .

They tell me the compressor plus controller costs about $1,200. As the BMW guys points out this compressor is actually smaller than the mechanically-driven one he replaced. So packaging looks OK.

However, to get comparable cooling capacity (i think we need 2-4 kW) we need to drive the compressor with 48 - 300 volts DC (300 being preferable). So now my problem is finding a 12V - 300V DC-DC conveter that can put out 10-15 amps.

With the exception of the boost DC-DC converter we're doing exactly what the eletric vehicle subculture does, so the path is largely paved. The exception is that they usually have high voltage battery packs and need to convert down to 12V to run conventional accesories. We have the opposite problem.

So if anyone knows the multi-kW DC-DC converter industry some pointers to sources would really help. An alternative would be a 12V-48V converter as you would expect to find in the telecomm industry. If we get that problem solved we're done.
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Old 23rd July 2010, 01:18 PM   #32
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Re: Electric A/C Compressor

if you use 48 volt converter won't you need one that puts out 80 amps to get 4KW. i would think a standard 110volt unit like is used to cool a motor home connected to a 110 volt converter would be simpler and cheaper. the problem is that the power required will still be the same and will require a very big converter. why not just drive a standard car AC compressor with a 12v electric motor and mount it where you have space. why does it have to be a single unit. I think I would go back and find a way to mount it on the engine. even if I had to move all the accessories on the engine to make it fit. you have to think that with all the years of automotive design all around the world that someone would have done this already.
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Old 23rd July 2010, 01:45 PM   #33
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Re: Electric A/C Compressor

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Originally Posted by Lynn Erickson View Post
why not just drive a standard car AC compressor with a 12v electric motor and mount it where you have space. why does it have to be a single unit.
I believe that the issue is that any compressor powerful enough to cool the cabin of a 40, or the "greenhouse" of a P4 or SLC, would need a 12V electric motor that was of greater power than available. The multiple motor issue is intriguing....but I really like the idea of mounting the A/C compressor under the front clip and eliminating all that "plumbing" required to drive it off the engine.

Quote:
Originally Posted by Dalton View Post
I'm sure friends of mine have had 4x4's with separate rear passenger electric motor driven A/C systems. A luxury version Landrover was one, if my memory is correct.
This is intriguing. I once took a long trip in a Suburban that had two-zone A/C, but it had two separate compressors mounted on the front of the engine, one for each zone. Landrover stuff is almost always premium priced, but if it were to allow someone to have A/C in an otherwise impossible situation, it would be well worth it in these high-dollar toys we're discussing here.

Doug
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Old 23rd July 2010, 03:37 PM   #34
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Re: Electric A/C Compressor

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Originally Posted by Lynn Erickson View Post
if you use 48 volt converter won't you need one that puts out 80 amps to get 4KW. i would think a standard 110volt unit like is used to cool a motor home connected to a 110 volt converter would be simpler and cheaper. the problem is that the power required will still be the same and will require a very big converter. why not just drive a standard car AC compressor with a 12v electric motor and mount it where you have space. why does it have to be a single unit. I think I would go back and find a way to mount it on the engine. even if I had to move all the accessories on the engine to make it fit. you have to think that with all the years of automotive design all around the world that someone would have done this already.
Yes on the 80 Amps, but as I said I'd rather use the 300 VDC unit and that's how I arrived at the smaller amperages.

When you say "standard 110volt unit" are you referring to a compressor or an entire AC unit? If I could find an appropriate compressor (designed for R134A that would run off 110VAC) I would just get a 12VDC-110VAC inverter. But so far I have not found a compressor like that.

I thought about driving the compressor I have directly but that requires a *very* large and heavy motor. I think I covered this earlier in the thread.

Why does it have to be a single unit? It doesn't. But because of the development going on for EVs there are now small light and efficient integrated units that are much more efficient than the conventional reciprocating compressors like the Sanden that came with my SPF.

As for mounting it on the engine, you may be confusing me with the original poster. I know how to mount it on the engine. I just don't want to. See my earlier post where I explain the rationale for moving it to the front.

Last edited by awatkins; 23rd July 2010 at 03:49 PM.
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Old 23rd July 2010, 03:47 PM   #35
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Re: Electric A/C Compressor

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Originally Posted by YerDugliness View Post
I believe that the issue is that any compressor powerful enough to cool the cabin of a 40, or the "greenhouse" of a P4 or SLC, would need a 12V electric motor that was of greater power than available.

Exactly. The Sanden compressor that comes with the SPF requires 6 kW at full output which is about 8 horsepower. That is one big mo-fo of a motor. If it were 90% efficient (unlikely in a 12V motor but let's be optomistic) it would try to draw about 9 hp = 480 A from my poor battery. Not gonna happen.

There's a reason why they mount these old fashioned reciprocating compressors on the front of the engine.

But, lucky for us, the "green" movement is resulting in electrical ancillaries that are much more efficient. They just tend to want higher voltages.
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Old 24th July 2010, 01:44 AM   #36
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Re: Electric A/C Compressor

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Originally Posted by awatkins View Post
Exactly. The Sanden compressor that comes with the SPF requires 6 kW at full output which is about 8 horsepower. That is one big mo-fo of a motor. If it were 90% efficient (unlikely in a 12V motor but let's be optomistic) it would try to draw about 9 hp = 480 A from my poor battery. Not gonna happen.

There's a reason why they mount these old fashioned reciprocating compressors on the front of the engine.

But, lucky for us, the "green" movement is resulting in electrical ancillaries that are much more efficient. They just tend to want higher voltages.
even if the so called new green compressors are 50% better (and they are not) power is power and if the new green ones only requires half of what the Sanden unit requires which is 4 hp you will still be drawing 240 amps from the battery. even if you use a high voltage unit it will still take the same amount of power ( watts ) to run it.
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Old 24th July 2010, 02:23 AM   #37
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Re: Electric A/C Compressor

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Originally Posted by Lynn Erickson View Post
...even if the so called new green compressors are 50% better (and they are not)....half of what the Sanden unit requires which is 4 hp you will still be drawing 240 amps .
COP for my Sanden is 1.5 at full speed. COP for the BMW project Sierra unit is 2.8 at full speed. Thats 86% better.

The 300V Sierra unit running at full power draws 6.6 A. At 14 volts, disregarding conversion losses, thats 141 A.

Last edited by awatkins; 24th July 2010 at 02:51 AM.
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Old 3rd April 2015, 01:52 PM   #38
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Re: Electric A/C Compressor

Old thread but came up my searches. Here is some new info on market.

JEGS Performance Products 51810, JEGS Remote Mount Electric A/C Compressor | JEGS Performance Products
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Old 3rd April 2015, 10:07 PM   #39
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Re: Electric A/C Compressor

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Originally Posted by Lukespoprtsman View Post
Old thread but came up my searches. Here is some new info on market.

JEGS Performance Products 51810, JEGS Remote Mount Electric A/C Compressor | JEGS Performance Products
Thanks Luke - very interesting information. I may take the leap for my Lotus project.

Dave L
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Old 4th April 2015, 02:57 AM   #40
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Re: Electric A/C Compressor

More on the same subject. looks interesting !

12 V Electric Air Conditioning Compressor – How Can You Decide Which One is Right For You? Sean Hyland Motorsport

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