I have always wondered about this one...
Refrigerators are one of the top energy consumers in homes.
In Northern climates, the outside temperature is colder than indoor
temperature at least 6 months of the year.
Why aren't they designed with "heat" exchangers to benefit from cool if
not frigid external air?
Even in warm climates (or summers) why isn't the same principle used to
vent the warm air from the compressor & coils outside rather than
loading the AC?
Presumably this could all be done by putting the evaporator coils
outside which would in turn decrease (or eliminate if cold enough) the
draw on the compressor during winter months.
Of course, installation might be a little more expensive, but with all
the focus on green-this and green-that why isn't this being done?
On Jan 28, 10:54 am, snipped-for-privacy@aol.com wrote:
A little more expensive? The cost of the install of a coventional
refrigerator is zero, you just plug it in. I replaced mine last year
with a 23 cft side by side with water and ice at the door. Operating
cost is about $95 a year. How much do you think you're going to save
in operating costs by moving the condenser outside? In many houses
you'd have to run how many feet of refrigerant tubing to get from the
fridge to a suitable location to house the outside unit? Factor in
installation costs (see the other thread here about permitting
requirements for similar installs) a more complex system, more points
of failure, shorter life due to exposure to the elements and you
clearly have a non-starter.
Also, what happens when it's 10 degrees outside? A regular
refrigerator won't operate below a certain ambient temperature because
of issues with the refrigerant and compressor.
>I have always wondered about this one...
>Refrigerators are one of the top energy consumers in
homes.
>In Northern climates, the outside temperature is colder
than indoor
>temperature at least 6 months of the year.
>Why aren't they designed with "heat" exchangers to benefit
from cool if
>not frigid external air?
CY: It does make sense, to me. It would be possible to put
the refrig backed up to external wall. Some kind of gasket
around the exterior of the fridge. Draw outdoor air for the
condensor. Winter time, that would provide better cooling.
Summer, to dump the heat outdoors. Window AC do that. Why
not refrigerators?
>Even in warm climates (or summers) why isn't the same
principle used to
>vent the warm air from the compressor & coils outside
rather than
>loading the AC?
>Presumably this could all be done by putting the
evaporator coils
>outside which would in turn decrease (or eliminate if cold
enough) the
>draw on the compressor during winter months.
CY: I suspect you mean condensor coils, but I know what you
mean.
>Of course, installation might be a little more expensive,
but with all
>the focus on green-this and green-that why isn't this
being done?
CY: Coordination between fridge makers, and home builders,
comes to mind.
On Jan 28, 12:54 pm, snipped-for-privacy@aol.com wrote:
Yes: Cool idea. Maybe.If fridges could draw in (and exchange) cool
outside air instead of using electrcity. But some refrigeration and
air controls would still be needed. Not sure the saving would be
significant if at all?
And with existing conventional electric fridges! Within the house all
the electricity used by the fridge ends up as heat. In our cool
Newfoundland climate some heating is needed most months of the year.
So in a house that is electrically heated (as most are these days) the
fridge heat merely replaces that from the electric heaters or other
means used for heating the home.
A fridge is basically an electric motor driving a pump that takes heat
out of the inside of the fridge and pumps it into those coils on the
back of the fridge. It's a heat pump. The motor also wastes some of
it's input (nothing is 100% efficient); it gets a little warm and that
heat stays within the house.
By putting say the coils outside might mean the fridge would run less,
thus saving electricity. But outside during a cold winter would
basically waste that heat outdoors. Warmth that originally leaked into
the fridge from the house and/or every time its door was opened, being
pumped outdoors. Same thing as running an air conditioner except in
this case it's only the fridge interior that is being cooled not a
room!
And since a 300 watt fridge can pump something say of the order of
1000 watts of heat; better IMO in cold weather to keep all the energy
used by the whole system within the house.
In a very hot climate the idea 'might' have some merit, if the cost/
complexity was reasonable? But pumping fridge heat outside into say 30
or 40 Celsius (90 to 110 F) atmosphere (Does it EVER get that warm
here?) outside might mean the fridge would have to run longer; thus
using more electrcity!
Overall the best course might be to have bulk of ones house
underground and utilize any/all sources of energy (mainly electricity
these days) entering it as a source of warmth. One of the bigger
'wasters' at moment being clothes dryers which chuck their warm damp
air outside. But anywhere else in the home that moisture can cause
mould/rot. That's why ventilation (especially attics) is so important.
Have seen a few homes here where there was a cold room built out fom
the basement, say under the front steps that stayed something close to
the temperature of a typical fridge. Useful for beer, potatos etc.
Because it's impractical and adds to the expense. Besides that it
wouldn't make a huge difference in the economics of operation seeing
you are not cooling more than 30 cubic feet for a home fridge.
When you consider commercial refrigerators/walk in coolers and
freezers and refrigerated displays in grocery stores, 99 percent of
those have a remote condensing unit.
I heard over 20 years ago that large grocery stores vent the condenser
heat to outside in the summer - the refrigeration does some of the space
cooling. In the winter they capture the heat and blow it back into the
store for space heating.
On Thu, 28 Jan 2010 10:39:00 -0500, blueman wrote:
If my freezer wasn't dumping hot air into the kitchen then for the 6
months it's cold outside I'd just be paying to heat that room by other
means anyway.
Besides, any modern bells-and-whistles replacement would likely be built
in a country with a poor environmental record, shipped halfway around the
world to me, and be built to the same shitty standards as everything seems
to be these days - such that it has a lifespan better measured in months
rather than decades, and I'd be buying another one quickly, then
another...
A refrigerator in a closed environment (in a home) will not only use
electric to keep it cold on the inside, but 100% of it's losses are heat
that is put into the home. You can't make anything cold. You can only
remove the heat and put the heat somewhere else. So it takes the little
bit of heat inside itself and puts it into your home, just like a heat
pump. Also every watt it uses is turned to heat that also warms your
home. The only way to benifit from cold outdoor air would be to put it
outside. But then we sometimes run into other problems.
Using warm or hot outside air will make it run longer and less
efficiently. If there would be any savings, it would be so small that
it wouldn't be worth the trouble.
The appropriate negentropic universe is at subchronon offset
SC.768564000007 precisely. However very strange things happen when you
run refrigerant lines into that.
BTW, consider that negentropic universes DON'T CARE if you don't know
what "negentropic" means.
*You reminded me of something that I saw in several homes and apartments in
Sweden many, many years ago. In the kitchens they had a dedicated cabinet
that had a vent pipe to the outside. This made the cabinet cold enough to
keep things fresh, but not frozen. The winters are cold, dark and long
there so these cabinets could be used for many months.
re: "In Sweden...In the kitchens they had a dedicated cabinet that had
a vent pipe to the outside."
When I was in the Coast Guard and stationed in Alaska, the windows in
our sleeping quarters were sealed shut, but there were 3 or 4 holes in
the bottom of the wooden sashes. The holes were filled with corks that
could be removed for fresh air.
I (as well as many others) removed the corks and screwed a styrofoam
lined wooden box to the window sill. The box had a hinged door and was
big enough room to hold a six-pack of your favorite beverage.
I used to enjoy the Miller nips (7-oz bottles). On the coldest days, I
could come back to my room, put a couple of warm beers in the box and
by the time I had washed up and changed into my civvies, the beers
would be ice cold.
You had to be careful...you could freeze a 12 oz can in under 10
minutes on some days.
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