Quote:
Originally Posted by randen
The quest for efficiency goes on.
A small compressor from a dehumidifier and a moderate airflow through the HX coils should do the trick.
What do you fellows think.??
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I think the idea is quite sound.
Using a dehumidifier is a great choice. You already have all the parts you need, and they just require a bit of re-arranging.
Dehumidifiers operate by chilling air until frost forms on the evaporator, then they go into a de-icing cycle (which is the removed humidity), then they begin again.
Some of the very small units just use a pause in the running of the compressor, and the ice melts. This might be aided by the close proximity of components, and a natural 'reverse flow' occurs... I'm guessing a bit here.
Some of them, larger units, use a reversing valve that reroutes hot refrigerant to the evaporator coil to melt the frost.
I'd recommend starting with a very small unit, remove the cover, let it run and observe how it operates.
I actually did this and it was very instructive. I measured the time between cycles of run-melt-run and found the time periods to be similar but not equal. This made me realize that the 'thingie with wires' that was attached to but not actually touching the lower part of the fins. It was in the area close to (but not exactly at) the place where the the refrigerant was spraying into the HX. It was a sensor of some kind, most likely a thermistor. It appeared that when the frost advanced to reach the sensor, the freezing temperature was the trigger to begin the defrost cycle.
So all the components are there. The two HXs will need to be separated so that outside air goes through the condenser coil, and inside air goes through the evaporator coil.
It might even be possible to gently separate the coils without rupturing the connecting tubes. It would be worth the try, but if they break, you have total power to reconfigure to your exact needs, and you know where to get the refrigerant.
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I suppose someone with astounding cleverness could re-purpose the existing circuitry. Otherwise...
Sad to say it, my friend... You will probably need to lose your Arduino virginity at this point.
Best,
-AC_Hacker