Electric Air Conditioning (AC) System

[The Dark Side of Will]

Interesting... I wasn't aware of that.
I guess the fancier compressor made its way through the model range as a function of feature and/or content creep.

At any rate, Caddies in the '90's (V6 Fieros and a bunch of other apps) still used cycling compressors.

[ericjon262]

here are a few compressor options:

http://www.rigidauto.com/24...v-dc-compressor.html

http://www.rigidauto.com/83...v-dc-compressor.html

http://www.masterflux.com/products/sierra/

First two are made in china, the "Sierra" doesn't list their country of origin, so I think it's fair to assume it's not made in USA, and probably china. there's more specs on their website:

the Sierras are rated from 1580-6500 btu/hr, but they are dual voltage, so I would imagine the 6500 btu/hr figure could only be attained at 24 volts vs 12 volts.

the rigid compressors are rated to 2900 btu/hr and only 12 volts.

both are R134a compatible.

[fieroguru]

A little further down the list there is Sierra02-0716Y3 that is 134A, 12V and 2840 btu, but pulls 36.4A

It would be great to have front mounted electric PS and AC... less clutter and weight in the engine bay. Also, would greatly simplify the alternator placement on the LS4 swaps.

[ericjon262]

I saw that, that's why I posted a range... but yeah, I really like the idea of it. I emailed them to see where exactly they are made, probably won't hear back until after the new year though.

[Series8217]

Do any of the hybrid compressors run on 12 to 16V? The pure electric car compressors are probably all 200V+, but the hybrids may still have a 12V electrical system.

The RockAuto listing for the second-gen Toyota Prius AC compressor says "12V" but web forums indicate that it runs on ~200V. There's a bit of information on the system performance here: http://www.epa.gov/cppd/Presentations/M ... verter.pdf

I'm kind of interested in this now, for the purpose of reducing system complexity and shifting weight to the front of the car.

Prius compressor diagram:

[Series8217]

None of the major automotive manufacturers are using low-voltage compressors because the required current draw would be something like 200A for a 12V compressor with cooling capacity similar to a normal engine-driven AC. Revolt EV sells the Masterflux compressors and talks about some of the limitations here.

[Emc209i]

Link seems dead Steven.

[The Dark Side of Will]

Do any of the hybrid compressors run on 12 to 16V? The pure electric car compressors are probably all 200V+, but the hybrids may still have a 12V electrical system.

I'm kind of interested in this now, for the purpose of reducing system complexity and shifting weight to the front of the car.

Even all electrics have to have a 12V power bus because of the consumer electronics, embedded automotive electronics and accessories (like light bulbs and LED's) that are set up for 12V... reinventing all of that for 200V would be prohibitively expensive; not to mention the potential safety aspects of having a 200V power buss go to every electrical load in the car. The only electrical loads in the car big enough to make 200V worthwhile would be the traction motors, A/C, heater and maybe engine cooling fans in a hybrid.

Even if it were feasible on 12V, is it worth adding the weight of the motor and electrical cabling when the current refrigerant tubes weigh just a couple of pounds?

[Series8217]

Do any of the hybrid compressors run on 12 to 16V? The pure electric car compressors are probably all 200V+, but the hybrids may still have a 12V electrical system.

I'm kind of interested in this now, for the purpose of reducing system complexity and shifting weight to the front of the car.

Even all electrics have to have a 12V power bus because of the consumer electronics, embedded automotive electronics and accessories (like light bulbs and LED's) that are set up for 12V... reinventing all of that for 200V would be prohibitively expensive; not to mention the potential safety aspects of having a 200V power buss go to every electrical load in the car. The only electrical loads in the car big enough to make 200V worthwhile would be the traction motors, A/C, heater and maybe engine cooling fans in a hybrid.

Even if it were feasible on 12V, is it worth adding the weight of the motor and electrical cabling when the current refrigerant tubes weigh just a couple of pounds?

200V cables carrying 15A should be lighter than the refrigerant hoses, blocks, tubes, and manifolds that go from the rear to the front of the car. The regulator/rectifier/inverter/step-up converter/whatever would add some weight though. Even if it breaks even, moving weight to the front of the car is beneficial.

Just simplifying the plumbing considerations for a motor swap is a major benefit. Electric power steering and AC would mean the only belt-driven engine accessories are alternators and water pumps. That simplifies packaging for swaps.

I'm investigating the possibility of getting higher voltage DC or AC outputs from the alternator. I could see the kit car crowd buying a lot of electric AC systems if there was a simple, powerful solution available that worked with the simple modifications to the rectifier or regulator to produce the required output for an efficient step-up converter to 200V.

[ericjon262]

200V cables carrying 15A should be lighter than the refrigerant hoses, blocks, tubes, and manifolds that go from the rear to the front of the car. The regulator/rectifier/inverter/step-up converter/whatever would add some weight though. Even if it breaks even, moving weight to the front of the car is beneficial.

Just simplifying the plumbing considerations for a motor swap is a major benefit. Electric power steering and AC would mean the only belt-driven engine accessories are alternators and water pumps. That simplifies packaging for swaps.

I'm investigating the possibility of getting higher voltage DC or AC outputs from the alternator. I could see the kit car crowd buying a lot of electric AC systems if there was a simple, powerful solution available that worked with the simple modifications to the rectifier or regulator to produce the required output for an efficient step-up converter to 200V.

Problem with an AC output from the alternator is it will be very far from constant frequency. which leaves you with inverters. it would have to be a pretty big inverter to handle the starting current of the compresser, even with a step up transformer. an alternator for a hybrid would have to have a high voltage output to charge the battery, I would say that's probably the best starting point.

Edit:

hybrid probably won't have a high voltage alternator, it will just charge off of regeneration through the drive motors, or charge at 12 volts, just each cell in parallel instead of series.

[Series8217]

I looked into building an automotive grade voltage step up converter that takes an input of 14V and puts out 100V, with support for loads up to 20A. It's doable with relatively inexpensive components. For example a Linear LTC3813 and an array of STW47NM60ND MOSFETs may form the major functional components of the circuit.

BTW who knows how to interpret the performance charts on these compressors, in the context of being used in a Fiero? http://www.masterflux.com/userimages/SI ... aSheet.pdf

[The Dark Side of Will]

Do any of the hybrid compressors run on 12 to 16V? The pure electric car compressors are probably all 200V+, but the hybrids may still have a 12V electrical system.

I'm kind of interested in this now, for the purpose of reducing system complexity and shifting weight to the front of the car.

Even all electrics have to have a 12V power bus because of the consumer electronics, embedded automotive electronics and accessories (like light bulbs and LED's) that are set up for 12V... reinventing all of that for 200V would be prohibitively expensive; not to mention the potential safety aspects of having a 200V power buss go to every electrical load in the car. The only electrical loads in the car big enough to make 200V worthwhile would be the traction motors, A/C, heater and maybe engine cooling fans in a hybrid.

Even if it were feasible on 12V, is it worth adding the weight of the motor and electrical cabling when the current refrigerant tubes weigh just a couple of pounds?

200V cables carrying 15A should be lighter than the refrigerant hoses, blocks, tubes, and manifolds that go from the rear to the front of the car. The regulator/rectifier/inverter/step-up converter/whatever would add some weight though. Even if it breaks even, moving weight to the front of the car is beneficial.

Just simplifying the plumbing considerations for a motor swap is a major benefit. Electric power steering and AC would mean the only belt-driven engine accessories are alternators and water pumps. That simplifies packaging for swaps.

I'm investigating the possibility of getting higher voltage DC or AC outputs from the alternator. I could see the kit car crowd buying a lot of electric AC systems if there was a simple, powerful solution available that worked with the simple modifications to the rectifier or regulator to produce the required output for an efficient step-up converter to 200V.

I don't think eliminating the under-car tubes would get rid of much weight. Hoses & tubes still have to connect the compressor to the evap, so you don't lose the full weight of everything that goes to/from the compressor... and motors are heavy. The 200A at 12V figure is 3 1/4 horsepower more or less continuous; not a small motor.

[Series8217]

I don't think eliminating the under-car tubes would get rid of much weight. Hoses & tubes still have to connect the compressor to the evap, so you don't lose the full weight of everything that goes to/from the compressor... and motors are heavy. The 200A at 12V figure is 3 1/4 horsepower more or less continuous; not a small motor.

The Masterflux Sierra compressors range in weight from 10 lbs to 15 lbs. That's for the pump and motor, but not the controller board. For comparison, most Denso compressors weigh ~15 lbs according to the shipping weights on Amazon.

I have an '88 4-cyl AC compressor line (from the compressor to the rear chassis manifold) sitting out in my garage I can weigh. I threw out my box of old compressors earlier this year, but 15 lbs sounds about right.

[ericjon262]

I took the lines out earlier this month, I would guess they weigh about 5-8 pounds dry.

[Series8217]

I took the lines out earlier this month, I would guess they weigh about 5-8 pounds dry.

If you still have them, can you put them on a scale?

[Series8217]

1988 Fiero 2.5L AC compressor to chassis refrigerant line assembly: 2.50 lbs dry

[ericjon262]

I took the lines out earlier this month, I would guess they weigh about 5-8 pounds dry.

If you still have them, can you put them on a scale?

I can try, they're kinda bulky.