"nahcr" wrote in message
roups.com...
responding to
http://www.homeownershub.com/mainten...nt-316736-.htm
nahcr wrote:
Thanks for your responses. However, i still dont understand why a heat
pump won't work. The heat pump we currently have is outside and it
functions fine until it gets really cold. So I would think that putting
it in the basement with a large air volume would mean that it would
function just as well, and that perhaps there would be a slight efficiency
gain on very cold and windy days or on very hot days since the basement is
sheltered from the wind and snow and shaded from the sun. My situation is
unusual because first in proportion to the size of the house, the basement
is very large, and second, the basement cannot be used except to run pipes
and keep the water heaters for the 4 units. I would like to put the pumps
there because they are ugly and that will get them out of my yard.
If the heat pump worked just as well in the basement as outside, i would
be quite satisfied. Is there some reason why this would not be true?
Is there any danger to the occupants in putting the pumps in the basement?
If the temperature outside went down to say 10 degrees F on the coldest
day of the year, would pipes in the basement freeze because of the heat
pump?

I'll say it this way: Heat pumps can only move heat (BTUs) around. Located
outside, your heat pump can exchange an infinite number of BTUs from the air
since it just grabs "new" air with a new supply of BTUs with its fan as
needed. So, it will work whether the outside air is warm or cold pushing the
BTUs in or out of the outside air (and your house). If you put the heat
pump in your basement, the BTUs the heat pump can grab are limited by what
the walls, floor and other materials contain or can transfer in/out. Since
the BTUs can't easily flow in or out of the basement volume of air, walls
and concrete, the heat transfer is not limited by the pump but by its source
of BTUs.

On a hot or cold day when your heat pump is trying to cool or heat your
house, it will run out of BTUs that can be pulled or pushed into your
basement. It then loses efficiency and will just run without doing any
heating or cooling. Meanwhile, your basement will either be way too hot or
way too cold. You may not care what the temperature of the basement is, but
your pipes could freeze on a cold day outdoors as the heat pump sucks heat
from the basement to put into the house. On a warm day outside, the heat
build up in the basement could be dangerous and damage wiring or the house
structure. Or, the heat could simply make the heat pump so inefficient, it
wouldn't cool the house; it would just waste electricity.

If you could fill your basement with water which has a much higher BTU
capacity per unit volume than air and concrete and use that water for your
heat pump, you might make your idea work; but there's also a good chance
that you would have a block of ice in the basement for much of the winter
and a pool of steaming water for much of the summer.

A neighbor of mine installed a ground water heat pump to heat and cool his
house. For a house of about 2500 square feet and well insulated, it takes
the water from 5 wells to supply enough BTUs winter and summer to keep the
house comfortable. It's very energy efficient because the high volume of
well water, either coming or going is always about 50 degrees F +/- 10
degrees., so it can either give or take plenty of BTUs, but drilling the
wells was expensive.

Tomsic