On Friday, September 4, 2015 at 12:45:07 PM UTC-4, M. L. wrote:
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?

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.

You're approaching the design from retrofitting today's refrigerator
design to today's homes. I'd think that the installation costs would
be near zero if homes and refrigerators were designed 80 years ago
with the outside usage in mind.


Eighty years ago or today, it still makes no sense because you're
trying to solve a problem that doesn't exist. It costs about $90
a year to run a fridge. In the cold winter months, that electricity
winds up as added heat in the house, which is a benefit. If we
assume you need heat 6 months of the year, it's like getting $45
worth of electric heat for free. With the proposed fridge,
that heat energy would be lost to the outside. In the spring and fall
it wouldn't matter much one way or the other, as the inside and
outside temps are about the same. In the few summer months, if you
have AC, all it would do is have the small amount of heat generated
go directly outside, instead of into the house and then removed by the AC.
So you might save whatever AC energy it takes to remove ~$20 worth
of heat from the house. That's maybe $7, because an AC has a COP
of about 3. So, by my analysis, what is supposed to be a better
design, actually costs more to run. You lose $45 and gain $7, for
a net loss of $38.




I've always wondered why northern homes weren't built with a small
enclosed but uninsulated area for a similar cold storage purpose.

Because many days it can get well above freezing, so your ice cream would
melt and your fish would spoil. At night it can get very cold,
so your soda and milk freezes. Those are reason enough for me.