Heat Pump Water Heater - Coil in Tube
 

So here's what I have so far. A copeland scroll compressor 115V (hopefully find 208v eventually). Made a coil of 20' of 3/8" soft copper by winding around a 2" PVC pipe. Inserted into a 4" PVC tube - capped sealed and ready to pipe in high side compressor. pic:

http://ecorenovator.org/forum/attach...121502_081-jpg

http://ecorenovator.org/forum/attach...103752_298-jpg

http://ecorenovator.org/forum/attach...103802_648-jpg

http://ecorenovator.org/forum/attach...103829_237-jpg

A pretty small 5000BTU/hr compressor will probably be plenty if it's only for DHW.

Ummm, how did you seal around the 3/8 tubing?

Sealed using a high temp automotive epoxy - 600 deg.tolerance.

Just wondering about dissimilar materials and the liquid pressure. I guess we will see.

Could be improved. Will have poor heat transfer because of very low water velocity in contact with cu tube. Water will flow straight thru the center.

That is known as a "high density" exchanger and if you mount it vertically it may not need a water pump. If you run a pump the water is going to need to do multiple passes to get hot.

Now, on to the hard part: the refrigerant circuit!

I'm riveted and wish you the best of luck.

It is the same as the thermosyphon HX I was talking about in another thread. I will work fine.

Acquario did a very similar HX for heating a swimming pool.

Here is how he did his coils:



...abd here is how he implemented his plastic shell:



He ended up modifying his basic design a bit. Yours may work right the first time.

Good luck!

-AC

It is a "tube in shell" (official term, if there is such a thing). Assuming it is placed vertically at the bottom of the tank, it will heat the body of liquid within it which will simply rise to the top of the tank, drawing from the bottom. No pump necessary.