Quote:
Originally Posted by Piwoslaw
You can clearly see that the compressors are simply plumbed in parallel, with no valves.
From what I've read, the controller turns on only one compressor at a time (in an alternating fashion). Some controllers keep an account of how much on-time each of the compressors has had and turns on the one which was used less often. When one compressor takes too long to do its job, then the second one kicks in.
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I'm really not an HVAC technician, but I think that they work differently...
Here is a quote I found on
this page:
Quote:
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...two compressors of these Trane Heat Pumps help with the efficiency rating because when there is a mild day, the smaller compressor of the two will work while the large compressor will work on the days that it may be extremely hot.
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...and on
this page:
Quote:
Two compressors are better than one. That's the message from HydroDelta, the latest manufacturer to announce a dual-compressor, ground-source heat pump. Most of the time the smaller of the two compressors can meet the house's heating or cooling load. Running the smaller unit closer to its capacity uses less energy. When the smaller compressor can't keep up, the larger one takes over.
And there is another efficiency booster. The evaporator and condenser coils are sized to match the larger compressor, so they are oversized for the smaller one. The dual compressors help HydroDelta's Meg-Tek heat pump reach very high efficiency with COPs up to 4.1 and EERs as high as 20.7.
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So, I think that it would be needed to use a simple check valve on the compressor output line of each compressor.
It also seems to me that with an arrangement like this would work pretty well:
- Compressor #1 = 400 watts
- Compressor #2 = 650 watts
- Compressors #1 + #2 = 1050 watts
An arrangement like this could give you three speeds with only two compressors.
-AC_Hacker
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