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View Full Version : What kind of C.O.P. can I expect in rejected heat from ice makers?



pwned
28-11-2010, 12:47 AM
It's not uncommon for apartments to have water bill included in rent, but electric bill is separate.

If you were to use a large ice maker to extract the latent heat of freezing using tap water(which you're not charged for), with whatever evaporator temperature ice makers run at, then throw out the ice outside every day, what kind of COP can you expect in rejected heat relative to electricity used?

Peter_1
28-11-2010, 09:40 AM
Te will be something around -10°C if you wants to freeze the water to ice and Tc around 40°C, gives a COP of +/- 2.8.
Thermodynamically seen, not such a bad point of view BUT, a big but, don't spill water, water is too precious to use it only to heat something an then throw it outside.
You often hear that there will become conflicts, even war for water.

We in Belgium may no longer drain the rain water in new houses in the main sewer pipes underground.
They install now everywhere two sewer lines and all new buildings must connect rain water to a separate line. Otherwise, like they did it before, the gray water from the houses which need to be cleaned back to pure drinkable water was diluted too much wit clean rain water. This rain water needs to be cleaned also together with the gray water which is a spill of energy. The intention is to reduce the mass of water that needs to be cleaned.

But that's of course aside your question but perhaps worth to consider in other countries. Remembers me when I was in the US in 2000, I was surprised the big quantity of water a flushing toilet uses over there.

pwned
28-11-2010, 04:04 PM
Te will be something around -10°C if you wants to freeze the water to ice and Tc around 40°C, gives a COP of +/- 2.8.
Thermodynamically seen, not such a bad point of view BUT, a big but, don't spill water, water is too precious to use it only to heat something an then throw it outside.
You often hear that there will become conflicts, even war for water.

We in Belgium may no longer drain the rain water in new houses in the main sewer pipes underground.
They install now everywhere two sewer lines and all new buildings must connect rain water to a separate line. Otherwise, like they did it before, the gray water from the houses which need to be cleaned back to pure drinkable water was diluted too much wit clean rain water. This rain water needs to be cleaned also together with the gray water which is a spill of energy. The intention is to reduce the mass of water that needs to be cleaned.

But that's of course aside your question but perhaps worth to consider in other countries. Remembers me when I was in the US in 2000, I was surprised the big quantity of water a flushing toilet uses over there.


I don't see much problem with clean water going into storm drain. I think the problem you're describing is water that isn't all that dirty going into sewer and overloading the waste water treatment plants.

Water for example is very scarce in Sparks, Nevada, however it is plentiful in the NW USA. No matter how much water I waste here, it doesn't affect the availability of water over there.

I think cooling tap water to ice instead of using running tap water to warm the evaporator is a fair compromise between efficiency (MY money) and water usage (landlord's money).

chilliwilly
28-11-2010, 04:12 PM
Make the most of what works for you.