Idea for solar assisted heat pump - Page 3

 
Yes, you will get something out of it, just not as much as a properly
designed heat pump. I think you would get more heat per KWH from a
refrigerator cooling covered tins of water to 5-10C.

You also have the considerable nuisance factor of schlepping all that
ice or water around every day, and the risk of spills. I fill my
washing machine with free hot water carried in kettles from the wood
stove or the solar collector, and dry the clothes on a line. I watch
the temperature and humidity inside and out, and open windows rather
than run the AC if possible. When someone starts preaching about
energy conservation to me I patiently explain how I keep my electric
bill so low with those and other techniques and watch their eyes glaze
over. The response is always like "You don't expect ME to do all that!"

 

JW:Yes, you will get something out of it, just not as much as a properly
designed heat pump. I think you would get more heat per KWH from a
refrigerator cooling covered tins of water to 5-10C.


-----
(arghhh!!! hate "Content-Transfer-Encoding: quoted-printable" that doesn't
provide for simple quoting of another poster's text)

But if you want to get the same amount of energy extracted from cooling
water to 5C (from a house of about 20C??) than you need a lot more water.
For that much cooling you'll get about 9 btu / lbm of water.  Freezing it
from 32F to 32F (0C to 0C) you'll get 144 btu/lbm.  So your technique may be
more 'efficient' in that the heat pump's COP is higher, but you'll need
about 16 times more water in your 'covered tins'.  So from 6 gallons we've
gone up to 96 gallons.


JM:
You also have the considerable nuisance factor of schlepping all that
ice or water around every day, and the risk of spills. I fill my
washing machine with free hot water carried in kettles from the wood
stove or the solar collector, and dry the clothes on a line. I watch
the temperature and humidity inside and out, and open windows rather
than run the AC if possible. When someone starts preaching about
energy conservation to me I patiently explain how I keep my electric
bill so low with those and other techniques and watch their eyes glaze
over. The response is always like "You don't expect ME to do all that!"

----
So you 'schlep' water around too?  Then what's the beef?  Of course the ice
jugs don't have to be open at the top, don't have to worry about spillage
all that much.

daestrom

 daestrom brought forth on stone tablets:

... and we are still talking about an hour or two's worth of heat...  So
you'd have to shlep the 96 gallons of water every hour or two.  Seems
like with all that effort, the heat would be unnecessary...

bob

 wrote:

I just copy and paste, then delete everything I'm not responding to.


Ice transfers heat by conduction while the water adds convection.
IIRC, ice cubes take several hours to freeze through, so the thickness
of a container that would freeze completely overnight is limited.
Water would cool in a galvanized trash can. Cover it either way to
keep ice off the evaporator coils.

The OP would have to carry the ice containers outdoors to melt it.
Water could possibly be rigged to siphon in and out through a hose by
raising or lowering the outdoor container. If the outdoor warming
container is sealed, like the old water heater tank in my solar
collector, the water could be blown to a higher level with compressed
air.

Jim Wilkins

 

Jim Wilkins wrote:


Why not simply 'reply' and delete the stuff that's of no longer of interest ?
Graham