Posted by News on October 29, 2006, 9:52 am
Just want to know what others think of this idea. Have a plastic pipe run
under the earth circled as in Heat Pump slinkies. But to improve matters
run this pipe through a collection of large water barrels above ground with
as much sun exposure as possble. Extract heat via the heap pump at the
hottest part of this system. A pump would pump heat from the ground 24/7 and
then the heat pump extracts the heat when needed. The heat from the
surrounding air, heating the water in the barrels has some gain too. The
mass of water in the barrels must pay a part.
Posted by Robert Scott on October 29, 2006, 11:29 am
One problem is that the water in the barrels above ground will get cold during
the night. And that is when your heat pump needs the heat the most. Combining
solar heat with heat pump technology is a good idea, but the solar heating part
should be done well before it can contribute to the heat pump. Now if the
barrels were in your house and were heated with passive solar and shielded from
the cold night by operable curtains or a Trombe (sp?) wall, then they would help
out a lot. But just having some barrels sit outside with no insulation will
probably do more harm that good.
Posted by News on October 29, 2006, 1:53 pm
OK. Have the barrels insulated, maybe in a well insulated shed. The heat
from the earth is pumped into them, then the heat pump takes away the heat.
The heat is being pumped into the barrels say 24/7 by a low wattage pump,
while the heat takes out the heat when it needs it.
Posted by Robert Scott on October 29, 2006, 4:21 pm
You have a strange concept of pumping heat from the earth into barrels. That
will only work if the earth is warmer than the barrels. So as soon as the
barrels reach the temperature of the earth, then they will hold no more heat.
The mass of the barrels is probably small compared to the mass of the earth in
contact with the underground slinky. So you are adding negligibly to the total
mass of stuff at the temperature of the ground, not to mention the fact that you
are slightly depleting the underground heat source. On the other hand, if you
are talking about gathering solar heat during the day in these barrels and then
using the relative heat in the barrels as input to the heat pump at night to
augment what comes from the earth, then you may have something.
Posted by SJC on October 29, 2006, 5:38 pm
Solar thermal collectors heating the barrel/tank fluid to warm the ground fluid
further makes some sense, but there is little storage reserve for long period of
cold and overcast. Having a heat store underground that is heated spring, summer
and fall could work nicely with a large array of solar thermal collectors.