The message
from "David Hill" contains these
words:

"..........You can make a heat pump for no cost at all, or very little -
assuming you can find someone with an old freezer they don't want ......."

Will a fridge do?

Yes, but you won't get a lot of heat concentrated from so small a
compressor. To do a decent job you really need an old commercial unit,
but a big domestic one would be reasonably effective.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

In message , Franz Heymann
writes

"David Hill" wrote in message
...
Following my posting re reverse thermostat, I have been wondering just
what
ideas the collective brains on this group could come up with for
Greenhouse/poly tunnel heating.
We get a lot of questions re Gas , electric or paraffin heating, but
surely
we can come up with something free/cheep and useable.

Such things are generally mutually exclusive. The closest is wind power
where you can buy reasonable 500W wind turbines for around £600. Or make
them from old alternators and scrap for somewhat less.

Your next best bet is a water wheel - provide you have a stream in the
garden.

I seem to remember talk of having bottles of water with washing soda in
solution in them, the idea being that when the temp dropped to below 50
then
the soda would crystallize giving off heat, and when the water was over
about 60 then the soda would absorb heat as it went back into solution.
Now have this in tanks with some sort of heat exchanger taking heat from
the
top of the house in the day and heating the tanks.........

I see no thermodynamic advantage in that, compared with any massive black
material in the tunnel to absorb heat during the day and release it during
the night. But you are likely to find that the amount of heat you can trap

There is some advantage in that the latent heat of crystallisation is
moderately large so the stuff manages to store more heat than plain
water can. And in theory it provides some weak thermostat action - the
bad news is that it can supercool and then bounce. And sometimes the
containers rupture due to volume change on crystallisation.

in this way is nowhere near enough to keep your greenhouse warm over night.
Let's face it, winter is winter because there is not much heat sculling
around.

At UK latitudes that is true, with short days and very low sun but at
latitude 45 or lower there is still real power available in the winter
sun.

Regards,
--
Martin Brown

The message
from "David Hill" contains these
words:

"..........You can make a heat pump for no cost at all, or very little -
assuming you can find someone with an old freezer they don't want ......."

Will a fridge do?

Yes, but you won't get a lot of heat concentrated from so small a
compressor. To do a decent job you really need an old commercial unit,
but a big domestic one would be reasonably effective.

--
Rusty
Open the creaking gate to make a horrid.squeak, then lower the foobar.
http://www.users.zetnet.co.uk/hi-fi/

"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts, which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

Franz

"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts, which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

Franz

"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts, which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

Franz

On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)
--

Knowledge is knowing a tomato is a fruit;
Wisdom is not putting it in a fruit salad

On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)
--

Knowledge is knowing a tomato is a fruit;
Wisdom is not putting it in a fruit salad

On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)
--

Knowledge is knowing a tomato is a fruit;
Wisdom is not putting it in a fruit salad

"martin" wrote in message
...
On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat
from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot
paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the
whole
fridge. Just install the motor and switch it on permanently. Or,
easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)

I did think of saying "paint it black".

Franz

"martin" wrote in message
...
On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat
from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot
paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the
whole
fridge. Just install the motor and switch it on permanently. Or,
easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)

I did think of saying "paint it black".

Franz

"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts, which is just about the amount its
motor will need to run, so you might just as well not bother with the whole
fridge. Just install the motor and switch it on permanently. Or, easier,
just run a 100 watt bulb permanently.

Franz

"martin" wrote in message
...
On Wed, 10 Mar 2004 15:50:08 +0000 (UTC), "Franz Heymann"
wrote:


"Jaques d'Alltrades" wrote in message
...
The message
from "Franz Heymann" contains these
words:

It's called solar heating with heat storage. Or if not using heat
from
the
sun heat pump systems can take it from the environment directly.

But unfortunately the price of a heat pump is so high that the money
spent
in amortising it might as well be spent buying electricity ot
paraffin.

You can make a heat pump for no cost at all, or very little - assuming
you can find someone with an old freezer they don't want.

That will deliver around 50 to 100 watts,

The energy delivered depends on the temperature of the heat source

which is just about the amount its
motor will need to run, so you might just as well not bother with the
whole
fridge. Just install the motor and switch it on permanently. Or,
easier,
just run a 100 watt bulb permanently.

What about light pollution? :-)

I did think of saying "paint it black".

Franz

And to think I thought we might get some lateral thinking going on the
subject.
I know we wont be able to get all our heat in Dec. Jan for nothing but oct,
nov , Feb March and april we should be able to generate enough free heat to
carry through most nights.
No talk of Bio digesters to use grass clippings, poultry manure etc. to
produce gas for our heaters
Looks as if I will just have to press on on my own.
Thanks anyway.
--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

And to think I thought we might get some lateral thinking going on the
subject.
I know we wont be able to get all our heat in Dec. Jan for nothing but oct,
nov , Feb March and april we should be able to generate enough free heat to
carry through most nights.
No talk of Bio digesters to use grass clippings, poultry manure etc. to
produce gas for our heaters
Looks as if I will just have to press on on my own.
Thanks anyway.
--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk