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Recover heat from freezer condenser? Answered

Anybody ever tried to use a freezer or fridge condenser to preheat water (before sending it to water heater)?
I'm thinking about an easy setup; a coil of copper tubing fastened to the condenser. I know It seems insignificant, but given the low cost of the setup, i think it could be worth it.




5 years ago

That copper tubing will leak and draw cockroaches, corrode plugging
your filters,  drip rot  part of your sub floor ( not insurable slow process ) and
after two years pollute your skin-water at the heat exchanger.


Why would the copper tubing leak, corrode etc.?

My experience with copper or stainless heat exchanger systems is
sadly very poor at couplings after a few years.  Glycol or water...

@steve Never would have thought about that, but a bit of 'inefficiency' does keep the system does keep it running smoothly eh?
The trick is (in my Canadian 'cold' climate at least) -- warm appliances aren't inefficient, because they're keeping the house above freezing, so 'wasted' heat from appliances and lights is actually just a savings on the furnace bill. It's a double-tap in a warm environment and you have to pay twice, once for the heat and once again for the cooling to pump that energy back out. If I'm keeping my house at 18C regardless of appliance usage, it just taxes the furnace more.

My favourite one I'm really fond of is the shower drain heat extractor to temper the incoming 5-15C water before the heater.

Another big waster in a lot of places is the clothes dryer. I vent my dryer into the house. All the heat and moisture from the dryer stays in the house and helps to keep it warm and helps with the struggle to get the humidity above 20 %

I've heard really bad things about doing that - unless you have VERY good filtration on a chemical level, the heat is good, the fumes are potentially toxic (hot plastic clothes, VOCs, fabric softener being cooked)...

I saw once a bubble filter to catch all the excess crud and lint. A heat exchanger and exterior exhaust wouldn't be bad except the condensation from incoming cold air would be a nightmare for the ducting.

I use a variant of this: https://www.instructables.com/id/Water-Lint-Trap-From-a-5-Gallon-Bucket/ in my house, and I've been very pleased. Given the current state of things, I don't really see this as very risky behavior.

totally fair; I grew up with my dad putting a sock over the internal dryer ducting.

You have to be a bit cautious, because many fridges use the line to make sure that the inlet at the compressor never freezes, which is not good for the compressor.