OK, here is an idea for do it yourself solar heat...

You get an ordinary small refrigerator.

You get 5 to 10 one gallon containers of ordinary water.

Paint the containers black if you like.

Build a small glass enclosure outside that you place the containers
full of water so the sun can warm them but they are isolated from
the
cold air. By the end of the day they are warmed to say 70 deg F.

At night, you bring the containers of water inside and place them in
the freezer section of the fridge. The fridge proceeds to pump the
heat out of them and into your home. After say 8 hours they will
freeze and you will have extracted the specific heat as well as the
latent heat of fusion by freezing the water.

The next morning, you place the containers now full of ice back out
in
the sun to thaw and re-heat.

Will wonders ever cease! FINALLY an on-topic post to alt.energy.renewable!

In alt.energy.renewable Mark yahoo.com> wrote:

Why not have a solar collector on the roof into which you pump a fluid
to be warmed.

When the fluid has picked up the maximum amount of heat, it is then dumped
into a container inside the fridge where the heat is extracted via the
refrigeration cycle.

A collector which comes to mind would be a tray with a glass top; the
fliud would be a thermal-transfer oil with a dark-colored dye.
There would be a thermal probe which would tell you when its time to
dump the fluid for heat collection.

As you mentioned, Rankine-cycle heat pumps have at least a 4:1 ratio of
heat output vs. electric input (1 KWe yields 4 KWt) as long as the
medium you extract heat from is above 40 degrees F. or so.

Wouldn't the freezer use more energy to freeze the warm water? And how
would the heat get pumped into your home via the freezer? Perhaps
freezers work diffirently in my part of the world?

On May 15, 12:38 pm, Mark yahoo.com> wrote:

In alt.energy.renewable AndreH gmail.com> wrote:

Yes the freezer uses more energy BUT for this space-heating application
we're getting that energy back with.

In this application we're using the refrigerator as a "heat amplifier";
the refrigeration cycle picks up heat from the fluid inside via the
evaporation of a "refrigerant" liquid ( R-12, R-134a etc ) inside an
evaporator matrix .

The refrigerant vapor which contains heat is then sucked into a compressor
which increases the vapor pressure inside a "condenser" where the
refrigerant vapor condenses back into a liquid.

As the vapor condenses, it gives up the heat it picked up in the
evaporator + the heat of compression added by the compressor.

We then remove this heat with a fan which blows air across the condenser
coils for our space-heating application.

RadicalModerate wrote:

...

Does the heat need to be "amplified" from a solar collector?

If the buckets of water that you take out of your solar heater are
warmer than the space you want to heat then it'll heat the space
without using a heat pump.

On May 15, 7:31 am, radicalmoder...@attnn.com (RadicalModerate) wrote:

sure you could even pump the fluid continuously, but then it won't
store heat for the night and it is much more complkicated to build,, ...

How hot do you thinlk the water will get, maybe 100? Thats only a 30
deg delta. Using a heat pump to bring the water to freezing also
extratct the latent heat of fusion. Its much more heat that way.

Mark

where do you think the heat goes that is extracted out of the food in
your freezer?

All the electrical energy that is used plus the specific heat of the
water plus the latent heat of fusion of the water is extracted and
used to warm the spce around the freezer.

Mark

Mark wrote:

I've heard of water in flat water heating panels reaching boiling
when left to stagnate (not circulating). Flat box solar ovens often
reach 200F without reflectors so I would imagine the water could
get very hot indeed.

How hot does it need to get anyhow? If you have enough of it then
only a small delta will suffice to warm any space. If you make your
collector very inexpensive then you can afford to make it larger
and therefore provide more heat.

Mark wrote: