AC Variable Orifice Valve
 

Here is an interesting three part article on the newer "variable orifice valves" (VOV) -- it is somewhat technical, but good information.

These valves are a drop-in change for the existing fixed orifice valves in most automotive AC systems.

http://www.imcool.com/articles/aircondition/VOV1.htm


Tom Piper

They've been out for at least a year. I remember reading about them last summer when I was doing some A/C repair work on my Vette.

Most of the pros on the Board at www.ackits.com say they're junk. Don't know of any OEM that uses them either. GM's variable displacement compressor (here's a brief overview: http://www.findarticles.com/p/articl...4/ai_n13780360 ) approaches it from a somewhat different angle, but of all the systems I've owned, that's been the only one that never gave me any problems (and it's nice to have something that never cycles).

IT would be neat to see some sort of modern safer version of a lithium bromide ac used on auto's to make use of all the waste heat.

You lost me - doesn't that stuff boil at 2500 degrees? I don't know how you would turn that into cold air unless you use the steam to spin the compressor??? Current designs is to remove the compressor from the accessory drive train - I think the hybrids all ready do - add a super capacitor to run it and maybe you've saved something - though the future promises 16 to 32 volt systems instead.

Look up lithium bromide, ice from fire, or adsorbtion cycle refrigerators and you'll find a bunch of info. They have been around for along time. The problem is it could blind someone.

We did a few projects where we where able to run a fairly nice sized adsorbtion cycle refrigerator off the exhaust of a typical household gas water heater.

See my post under the "134 Super" title. It's been about 3 years since I installed a varible orifice tube. I did it at the same time of the Freeze 12 conversion, so I don't know how it relates to the final performance of the system but I couldn't be happier. Many thanks to Sun CR for the guidence in getting the system going, but note he wasn't the one who recommended the Freeze 12.