Electric A/C Compressor

#1
Trial fitting the 302W, I have discovered, as I'm sure many others have, that space is incredibly tight.

Been able to mount the alternator and get it to fit, but the A/C compressor is a larger, more dificult package. Worked out I can possibly mount it beside the sump, but the plumbing would be the lowest point, not an ideal situation.

Thinking laterally, has anyone had any experience of electrically driven A/C compressors? Could solve a number of problems.

Clive
 
#2
Clive,

The Sikorsky S76 I maintain at work has an electrically driven R134A compressor.

Problem is its a 28v system.

Perhaps a motorhome rooftop system is 12v?

That is where I would start looking.

Cheers,
Scott
 
#3
Clive
You could fit a small compressor,as the cabin size is small it wont be a problem.
Diahatsu. suzuki late corolla all small.

You will have to make brackets ect ect

Jim
 
#4
Clive,
Haven't heard of one being used. They take a lot of torque to drive and you would have to find an area to put it in. Then there is trying to get a DC motor or an inverter and a motor. As you said space is at a premium. If you are keeping your water pump, you should be able to mount it as you will have alot of space with the water pump pushing your motor back. If you go to an electric setup which I did, you lose a lot of that space(engine moved forward to help weight distribution), and you have to plan a lot more. I have many pics of how guys have mounted their set ups. If you are interested I can furnish them to you. Your best bet is at the lower side of the front of the engine opposite the alternator. Here is what my setup looks like. Its a 351W but this area is the same.


You may have to fab a custom support as I did. If you are going for a serpintine setup, you are on your own. V belts allow you the option of moving things around "a little".Notice how close mine is.


Mine isn't a dry sump, but you get the idea.
I have a question. if you are putting A/C on your car, why are you adding a dry sump? If you are going to occasionally track the car as I am, an Accusump will do just as well if use a good gated oil pan. You will also need a low pressure(oil) cut off switch to shut down the fuel pumps if these fail and the oil pressure drops. I have mine wired that way with a bypass button for cranking the engine along with an Inertia switch. I can't keep my eyes on the gauges all the time!! If I have an abrupt stop or roll over, I want the pumps to stop then as well.




Bill
 

Randy V

Administrator
#6
My 2007 Toyota Camry Hybrid has an electric R134a Compressor and it will freeze you right out of the car.. I believe that most hybrids have them because the gas engine shuts off when you stop - even when the AC is on..

This is not a picture of my car's engine bay, but it looks just like it. The AC Pump has the red electrical connector on it. It's about the same physical size as most AC pumps..

 

Wally

New Member
#9
HI Those pretty orange Wire are H. V. 200 VOLTs DC !!!! and are nothing you want to play with if memory serve Me correctly, As this runs off the H. V. battery at 200 VOLTs D.C. I was working on a Prius I think the Systems are the same. Wally
 

Randy V

Administrator
#10
Is it a 12V DC pump, Randy?

Doug
Hmmm... As I didn't really know what voltage the AC Pump ran off of and the other posts got me to thinking... I checked it out...

On my car it's apparently 245v DC;

https://techinfo.toyota.com/techInfoPortal/staticcontent/en/techinfo/html/prelogin/docs/camryhv.pdf

A high voltage motor driven air conditioning compressor rated at
245 Volts.
Sorry 'bout that....

---

My past two motorhomes had roof mounted Air conditioning, but they were 110v AC units that would only run if you had your genset going...

BUT

That would not stop you from running a somewhat smaller 110v AC compressor off of an inverter..

Like these fellows are working on;
EV air conditioning - DIY Electric Car Forums


---
 
#11
Clive,
If all else is not feasible, you might consider the Redneck way of adding airconditioning to your car.:laugh::laugh::laugh::laugh: Its a Southern thing!!!!!



Bill
 
#15
I have some experience with this because I have spent so much time fooling around with boats.

The 12volt refrigeration compressors that are used in Waeco and Adler-Barbour marine refrigeration systems are made by Danfoss. My understanding is that they are quite reliable. You might also look at RV units- call a shop which does electrically driven RV units and see if they are 12vdc. I am certain that Danfoss compressors are 12vdc. RV units, however, may be driven off a generator set- many RVs have 120vac or 240vac systems just like boats do, and the AC is driven off that, or by shore power when plugged in.

The advantage of a DC compressor is that you can put it anywhere convenient. The disadvantage is that it is going to require a more robust alternator to run it, and you will need to dissipate the waste heat somewhere, in a car that is already cooling-challenged. But there are plenty of front-radiator/rear-engine cars with at least acceptable AC, so it isn't impossible.
 
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#18
The advantage of a DC compressor is that you can put it anywhere convenient. The disadvantage is that it is going to require a more robust alternator to run it, and you will need to dissipate the waste heat somewhere, in a car that is already cooling-challenged. But there are plenty of front-radiator/rear-engine cars with at least acceptable AC, so it isn't impossible.


It's actually better than that. If you look at this problem from the perspective of an SPF GT40, which comes with a well-integrated but mechanically-driven A/C system, the only change is the compressor. By taking it off the crankshaft you are relieving that drive system of that load (call it X watts), which you then replace with a larger alternator, which simply brings back the same load plus some, but its dynamics are very different (that is, better):
  1. It's total long-term power consumption is some conversion factor larger than the original long-term mechanical load due to the inefficency of converting mechanical energy to electrical and back. The alternator/motor combination might have a conversion overhead of say (being conservative) 30%. So worse case, where the A/C is running at full power 100% of the time you now you need an alternator capable of driving its original load plus 1.3X. In a world awash in 200A alternators that could replace a (say) 60A original, we now have an extra 140A to play which is equivalent to nearly 2.5 HP.
  2. However (and this is a big however) the electrical drive case has the huge advantage that there is a battery there that will happilly supply all the short-term load the A/C system is likely to come up with. The alternator really just needs to be able to top up the battery before you need to start the car again. So now we've levelled out the load on the alternator tremendously such that it could probably support a compressor peak load of several times that 2.5 HP. Or it could be smaller than 200A. (Just be sure that when you're crossing the Kalahari in summer to switch off the A/C for a few minutes before you shut off the engine so it will start when you come back out of the bar.)
As for "dissipating the waste heat somewhere" that doesn't count. You have that problem no matter how you drive the compressor; that's inherent to air conditioning of any kind, and its feasibility and implemenation is proven in every SPF GT40. And you can always add more fan horsepower now that you have that big alternator.

So to me this is practically a no-brainer just like electric water pumps are; now you get to put the stupid thing wherever you want, like up in front between the condensor and evaporator thus saving about 10 ft of refrigerant hose that no longer has to run down the tunnel. By doing that you've also made the refrigerant system more efficent, and you no longer need a big heavy bracket and a belt on the front of your engine. So from a weight and complexity point of view it's at worst break-even.

Besides, you want to put a dry sump pump there. Well... I do.
 
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#19
The 12volt refrigeration compressors that are used in Waeco and Adler-Barbour marine refrigeration systems are made by Danfoss.
Jim --

We may have a problem of scale because of the difference between refrigeration and air conditioning. The DC compressors Danfoss shows are for vehicle refrigerators and thus are in the range of a few hundred watts cooling capacity. However, the Sanden SD7H13 compressor that came with my SPF has a cooling capacity of six thousand watts (20K BTU/hr). (Power consumption is 4 KW).

Furthermore, the AC vs DC issue isn't a deal killer since these days a multi-kilowatt inverter is no big deal (relatively speaking; this being the 500 HP club). So boats, being sort of like GT40s in that they are light and subject to high-Gs, would likely have the right kind of electric air conditioning compressors that we need (residential units will not do for those reasons).

So, who are the popular manufacturers for A/C compressors for boats?
 
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#20
Clive,
If all else is not feasible, you might consider the Redneck way of adding airconditioning to your car.:laugh::laugh::laugh::laugh: Its a Southern thing!!!!!Bill
You guys can laugh, but I'm here to certify this is a California thing too: I used to hang with some rocketry guys who every month head to the desert. I needed a cool place to be so I hung a 13,000 BTU/Hr domestic window unit on a side window of my E-150 van, just l like in the picture, and powered it from a 3,000 VA generator.

I was classier because I left the generator on the ground, and MY generator is a Honda, not some trailer trash open-frame thing. Sheesh. Some people.

BTW, none of you commented on the tail lights. I got a set for my GT40.
 
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