Frozen HX
AC-Hacker
The hybrid heat exchanger your looking at is a hose thats typically used in whirlpool/hot tubs. It is 1 5/8 ID It 26 ft long and encompasses 3 pcs 3/8 copper tubes (twisted for turbulance) It has about 11 squre feet of copper surface area for heat exchange.
In heating mode the delta T looks good The refrigerant left the heat exchanger 1-2 degrees lower than the loop temp going in.
In air-condition mode as the air handler would have a delta T of 15 deg C or so the water would enter the HX at 20 deg C and drop to 5 deg C With a large amount fo heat leaving the condenser the evaporator was really cold
-15 deg C. I noticed through the day that one of the three copper tubes began to freeze than another followed by the last. I'm thinking that in air-conditioning mode with no antifreeze given time the icestarts to coat the copper tubes and migrates up the HX as the ice esentually insulates the copper tubes. This is another reason for the inclusion of antifreeze.
Back to the rest of the story. As the ground loop circulation pump cavitated in air the ever-expanding ice in the HX caused the outside plastic shell to split. And it made me grumpy.
To answere your last question. How did you prevent it from leaking double hose clamps and custom stainless ends. See photo of assembly this is the condensor only 2 copper tubes.
My new 5 ton 3 phase compressor awaits me at the border. Guess who's passport just expired.
Randen
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