integrated home refridgerator
 

My mother is once again in the market for both a refridgerator and a water heater. She likes the idea of my GE Geospring for the water heater and we were discussing options for the fridge.

This got me thinking of integrating the two appliances. I found a few posts that mentioned this idea in passing but it seems to me a interesting enough idea to start a thread.

I propose two directions to look into.

First, an average size ~22 cubic foot custom cabinet or modded fridge in the kitchen plumbed through a modded small window A/C unit to an adjacent water tank heat exchanger.

Second, a larger custom closet in the basement, possibly walk in with a chest freezer inside. Again plumbed through a medium size modded window type A/C unit to a water tank heat exchanger.

I have not yet done any calculations, but I guess the first would at least be a good pre-heater for a small on-demand water heater and the second might be enough for a medium size house's daily hot water needs.

Either way a super insulated box and an A/C feeding a tank as a preheated supply should be doable.

After thinking about this over night I am doubting it would be more efficient.
Warming water that is cold from supply would be good but the warmer the water, the harder it would be. The cold side would be just as bad. Cooling from room temperature would be OK but keeping a cold fridge cold would not be a good place to collect heat to warm the water.
Lastly, the worst case scenario would be a vacation where we need cold in the fridge but don't need hot water. The water would soon reach a temp where it would be very inefficient to cool the fridge.
In a high occupancy building it might work with lots of water usage but a home is not ideal.

You might be giving up too soon...
 

You might be giving up too soon...

Did you gather any data regarding how much power those appliances you were considering, actually used? This could point you in the direction of the most complimentary appliances.

There already are some combined appliances in Europe. One that I know of is a small active HRV that scavenges heat from outgoing air (after the HRV) and dumps the heat into a water heater, or alternatively a pre-heater.

Also, if you are running an A/C for the cold air it produces, and a refrigerator, you could dump the heat into a ground heat reservoir.

You'd be raising the efficiency of your cold-producing appliances all year long, and if you use geothermal heating, you'd get the stored heat back in the winter. Figure that heat travels about 2 feet per month in dry earth.

Also, I have seen heat pump water heater installations where the cold air output was directed into the living space during the summer to assist with A/C and directed outside in the winter when it wasn't needed. Outside air was use as the input in both cases.

-AC

What if you just plumbed in a section of copper pipe right at the compressor discharge, like the airtap A7? Fed to a 5 or 10 gallon insulated tank, then on to the condenser already in the fridge. The tank would initially raise the performance of the fridge due to added heat transfer, then store heat for on-demand hot water. Every time water was drawn from the unit, there would be a boost in cooling performance.