On Fri, 22 Jun 2012 07:01:56 -0400, Jim Wilkins wrote:

"mike" wrote in message
...
On 6/21/2012 9:52 PM, Winston wrote:
Use your refrigerator to dry the air in your house.
...

I'm interested.
Just how does this work?

Refrigerators work by moving heat from a couple of insulated
compartments to the outside environment. As the air in these
compartments falls in temperature, it passes it's 'dew point'
which is the local temperature at which the water vapor in the air
separates from it or 'condenses' on to the metal parts of the
refrigerator that are responsible for removing the heat (the 'evaporator'
and associated brackets).

http://upload.wikimedia.org/wikipedi...rigeration.png

This leaves the air in the compartments much dryer but poses an
inconvenience as the compartments are opened and closed every day.
That is, the water or 'condensate' forms ice and frost on the surfaces of
the evaporator (and associated metal parts). Eventually, the insulating
properties of the 'frost' causes the efficiency of the refrigerator to
decrease.

At that point, the frost and ice should be removed to re-establish
efficient function. We call this process 'defrosting'.

We don't defrost manually any more. Modern refrigerators and
freezers automatically shut down the compressor and heat the evaporator
every 8-12 hours for 20 to 40 minutes to melt the frost and ice to its
liquid form, a kind of distilled water called 'condensate', which is
allowed to collect in a shallow tray called a 'drip pan'.

As part of the defrosting process, a fan near the drip pan mixes ambient
air with this liquid and causes the condensate to 'vaporize' or mix again
with the air near the refrigerator in a cycle that continues as long as
the refrigerator functions.

You gonna leave the door open?

No.

Please show your work. I'd like to see the thermodynamics math that
says this is a good idea.

I wouldn't understand the math but this is a good idea because the
refrigerator can produce several ounces * of condensate an average of
three times a day anyway. Better to use this water and benefit from
somewhat dryer air than allow it to continue it's wasteful cycle, yes?

It's a waste of energy if the water freezes on the evaporator coils and
needs trough heater electricity to defrost.

I agree, but that's how refrigerators work. Honestly, I would much
rather the power company defrost my refrigerator than go back to
the days of manual defrosting, though.

It might work if you
disassemble the freezer compartment and blow enough air on the
evaporator with a fan to keep the temperature above freezing.

It works anyway. Very little modification is necessary to take
advantage of this "dehumidifier".

Still it doesn't match a window A/C unit that dumps the condensor's heat
outdoors.

I didn't say it did. It *will* allow the user to save some amount of
energy going to the window A/C unit because the dryer air will be
perceived as cooler to the user. On milder days, some users would
not even feel the need to turn on their A/C.

--Winston

--

* I *love* the word 'ounce'.
It is universally useful and can indicate volume, force, thickness,
density or practically anything else (including a kind or Roman coin or a
snow leopard).