View Single Post
  #87   Report Post  
Posted to alt.home.repair
[email protected] trader4@optonline.net is offline
external usenet poster
 
Posts: 4,500
Default Energy savings of a ' fridge

On Apr 18, 12:03*am, Richard J Kinch wrote:
Don Klipstein writes:
* Amount of electrical energy to pump a given amount of heat energy
* from
indoors to outdoors is about 1/3 of the heat energy. *Ideally the
ratio is 3.41 divided by EER of the air conditioner.


That's true, at least for air conditioning serving a small delta T of
indoors to outdoors. *Not so efficient when delta T is many times
larger, going from 0 deg F freezer to warm outdoors. *Think about why
heat pumps for home heating aren't used when it is the mirror image of
refrigeration, with 0 deg F outside and room temp inside.

* And heat energy output of a fridge is same as electrical energy
consumption of the fridge, plus only a tiny bit more for heat coming
out for items going in warmer than they are coming out - it's close
enough to equal to the electrical energy going into the fridge.


Conservation of energy of course applies. *But if you consider the
multiple heat cycles that exposed water in the freezer goes through
(chill/freeze/sublimate/condense/freeze/defrost/evaporate/condense),
you'll understand why the electric energy consumed per BTU spoils the
3:1 rule of thumb. *And why it's not therefore in the DOE test.

You can easily prove this to yourself with a duty cycle meter on your
refrigerator/freezer, and measuring while making and storing ice, versus
icemaker off and no exposed ice. *In my experience you go from running *
constantly while ice is being made to running quite intermittently when
there is no icemaking or exposed ice. *A puddle of liquid water in a
freezer is like a campfire in there, pushing the temp towards 32 deg F
when the freezer wants to shut off at 0 deg F.



Your experience with ice makers is totally different than mine. I
don't notice any difference in running time on mine when it's making
ice versus when it's not. It's most certainly NOT running all the
time when making ice. Good grief, the amount of water that's frozen
over a period of about an hour and a half is very modest, maybe a cup
or so. You can do the math, but clearly the heat contained in that
small qty of water should not make any decent refrigerator run
constantly.

Also, you vastly overestimate the sublimation effect. Sure, ice will
SLOWLY sublimate. If I leave the ice maker full, unused and off,
after maybe a month, the volume will diminish by 1/3. So, we're
talking about what? A quart of extra ice it has to make in a month?
Sure it uses some energy, but in the grand scheme of things, I don't
see this being a big factor. How about all the foods one puts in
the freezer that go in above room temp, like two quarts of soup?
Isn't that what the freezer is there for and supposed to do? Yet
making some ice is supposed to be a big factor?