Air conditioning

[reluctantartist]

So I was looking around at ac options and I came across this.
http://www.seanhylandmotorsport.com/blog/12-v-air-...t-for-you/

With a higher output alternator this looks like it could be a viable option.
_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

[raygreenwood]

Not likely in an aircooled normal engine.... at 24-31amps running and it will need about 2x that for start up cycle......and then add in everythiny else in the system at max emergency rain at night.....style usage.....and you will need a HUGE alternator. That......and 6,000+ BTU is quite small. Not bad but not stellar.

But...its a great concept and for a water cooled mid sized engine that can spare the load.....not bad. Ray

[Lars S]

Just trying to understand the system:
Input: 25A at 12V equals to 300W.
Output: 6000btu/h equals to 1800W.

So the cooling factor COP is 1800/300 = 6.
Normally in a car AC system the factor is about 2 to 4 as far as I know.

Not saying that something is wrong...just trying to understand...

Lars S
_________________
Porsche 914 -72, Bahia Red daily driver
VW411 2-d -70, White, sold
VW412 4-d, -73, Gold Metallic, daily driver
Suzuki T500, -69, Candy Gold, sold
Suzuki K50, -77, Black, daily driver
BMW R69S -69, White, sold
Husqvarna 118cc, -47, Black, Sold

[raygreenwood]

[Lars S]

[raygreenwood]

I could see this being used in say......a van/SUV based small RV....that already has a huge alternator.....like 125-150, amp running off of a V6 or V8.

See the strange thing about going the route of electric AC.....is that it is really unnecessary. If you are willing to spend....or fabricate. ....at that level.....just get a modern up date variable stroke AC compressor.

There has been a lot of research into AC compressor systems in conversations over on the STF.
Modern AC compressors like those on my 2006 Jetta and my 2012 Golf....and on most other modern cars since say....the mid to late 90s.....use AC compressors a helical drive, swash plate system with an infinitely variable piston stroke. They use a bypass refrigerant bleed that bleeds head pressure to crankcase side on the compressor to vary the stroke length while running....based on rpm and engine load.

So in traffic....at low rpms.....the compressor runs a stroke that may only be a few millimeters.....and takes very small percentage of power from the engine to run. Ae long as the interior of the car and the coil under the dash has already been generally cooled down....the compressor supplies enough pressure and refrigeration to keep it cool.

As you accelerate the compressor stroke and efficiciency increases. It also drops down to low again at highway speeds. Some use a combination of controls inputs to the electronic bleed valve....that takes inputs from thermostat and control valve as well as line pressure etc.....others are just rpm based.

The issue for getting one of these modern compressors is finding one that fits and has the correct direction of rotation for an ACVW. But if you are willing to fabricate bracketing.....you can make one fit.

The bypass valve control could probably be controlled directly, from a, dash rheostat. So you start out on high....using max power from the engine like and old school AC compressor....about 5hp draw.....until you get the car chilled down. Then turn the knob down to say about 5% just to keep you cool.....and you end up using maybe 1/2hp draw for highway cruising.

I know the AC on my Golf...what little I use it.....affects my highway gas mileage by maybe 1mpg Max. Also you cant feel any drag in driving in traffic. Ray

[ClassicCamper]

I had a 1970 411 underdash restored by Gilmore Enterprises. He never disappoints:

The compresor is already installed in the engine.

[raygreenwood]

Nice!
Ray

[ClassicCamper]

Received my condenser from Gilmore a few days back. This is designed to to sit in the spare tire well with a plastic cone over the top, thus allowing the tire to still reside in the trunk. If this Gilmore system works as well as those I installed in a couple of my last beetle and bus restos, I'll be styling come the summer months. Here is the piece:

I do have copies of VW Air Conditioner part/schematic books with ZVW part numbers as well as the break-out of every nut and bolt used to run the A/C units from all ACVWs 1967-80. I don't break these sets up, but since I'm partial to my T4 friends, PM me and we'll see what we can work out if interested. I'll keep everone posted as to how this build goes via this thread.
_________________
1973 412 Wagon
1976 Westy
1978 SB Vert

[raygreenwood]