"David Hill" wrote in message
...
I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.

Could you elaboraye a little? I don't understand.


The problem is I am wondering if I can get some form of thermostat that
will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

There are surely thermostats around which switch fans on then the
temperature gets too high.
Have you ever opener up an ordinary thermostat to see what kind of contacts
there are inside it?

Franz

The message
from "David Hill" contains these
words:

I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.
The problem is I am wondering if I can get some form of thermostat that will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

An ordinary thermostat for something like air conditioning. You'll have
a bonus there that if the temperature drops too much (esp during the
night) it will switch on a heater.

Alternatively, if you are feeling handy, buy an ether-filled capsule for
an incubator and make a frame to hold it and a microswitch, so that when
the capsule expands it works the microswitch.

You need an adjustment behind the capsule - nut and bolt, or something,
so that you can set the temperature it switches at.

Most microswitches have a feed and two line contacts. You can either
arrange it to be pressed 'on' or pressed 'off'.

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

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

"David Hill" wrote in message
...
I have this idea to draw the heat from the top of my Large poly tunnel
and
to duct it through a channel of concrete blocks and gravel to form a
heat
sink.
The problem is I am wondering if I can get some form of thermostat that
will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

I can only say your electrical wholesaler is an idiot, there are any
number of manufacturers who make thermostats that can turn on or off on
temp rise or fall or even with a two way or two pole switch do both.
Honeywell would spring to mind but there are many others.
--

Chris Thomas
West Cork
Ireland

The message
from "David Hill" contains these
words:

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

If you can afford it you'd do better to have several interconnected
plastic drums well buried under the greenhouse beds and filled with
water. A copper pipe riser to the top of the greenhouse, along the
top/ridge, and back down to the far end of the drums, and a thermostat
on the pipe so that when it reaches a preset temperature it starts a
small central-heating pump.

That way you can have warm beds heating the air in the greenhouse during
the nights.

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

"David Hill" wrote in message
...
I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.

Could you elaboraye a little? I don't understand.


The problem is I am wondering if I can get some form of thermostat that
will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

There are surely thermostats around which switch fans on then the
temperature gets too high.
Have you ever opener up an ordinary thermostat to see what kind of contacts
there are inside it?

Franz

The message
from "David Hill" contains these
words:

I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.
The problem is I am wondering if I can get some form of thermostat that will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

An ordinary thermostat for something like air conditioning. You'll have
a bonus there that if the temperature drops too much (esp during the
night) it will switch on a heater.

Alternatively, if you are feeling handy, buy an ether-filled capsule for
an incubator and make a frame to hold it and a microswitch, so that when
the capsule expands it works the microswitch.

You need an adjustment behind the capsule - nut and bolt, or something,
so that you can set the temperature it switches at.

Most microswitches have a feed and two line contacts. You can either
arrange it to be pressed 'on' or pressed 'off'.

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

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

"David Hill" wrote in message
...
I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.

Could you elaboraye a little? I don't understand.


The problem is I am wondering if I can get some form of thermostat that
will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

There are surely thermostats around which switch fans on then the
temperature gets too high.
Have you ever opener up an ordinary thermostat to see what kind of contacts
there are inside it?

Franz

The message
from "David Hill" contains these
words:

I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.
The problem is I am wondering if I can get some form of thermostat that will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

An ordinary thermostat for something like air conditioning. You'll have
a bonus there that if the temperature drops too much (esp during the
night) it will switch on a heater.

Alternatively, if you are feeling handy, buy an ether-filled capsule for
an incubator and make a frame to hold it and a microswitch, so that when
the capsule expands it works the microswitch.

You need an adjustment behind the capsule - nut and bolt, or something,
so that you can set the temperature it switches at.

Most microswitches have a feed and two line contacts. You can either
arrange it to be pressed 'on' or pressed 'off'.

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

The message
from "David Hill" contains these
words:

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

If you can afford it you'd do better to have several interconnected
plastic drums well buried under the greenhouse beds and filled with
water. A copper pipe riser to the top of the greenhouse, along the
top/ridge, and back down to the far end of the drums, and a thermostat
on the pipe so that when it reaches a preset temperature it starts a
small central-heating pump.

That way you can have warm beds heating the air in the greenhouse during
the nights.

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

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

The message
from "David Hill" contains these
words:

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

If you can afford it you'd do better to have several interconnected
plastic drums well buried under the greenhouse beds and filled with
water. A copper pipe riser to the top of the greenhouse, along the
top/ridge, and back down to the far end of the drums, and a thermostat
on the pipe so that when it reaches a preset temperature it starts a
small central-heating pump.

That way you can have warm beds heating the air in the greenhouse during
the nights.

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

"David Hill" wrote in message
...
I have this idea to draw the heat from the top of my Large poly tunnel and
to duct it through a channel of concrete blocks and gravel to form a heat
sink.
The problem is I am wondering if I can get some form of thermostat that
will
switch ON when the Temp rises and OFF when it falls.
My local Electrical wholesaler doesn't know of anything to do the job.
Any ideas?

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk

I have one I don't need in good working order, get in contact if interested
and I can give you details (free to good home!!)

--
Charlie, gardening in Cornwall.
http://www.roselandhouse.co.uk
Holders of National Plant Collection of Clematis viticella (cvs)

On Sat, 6 Mar 2004 03:03:06 GMT, Jaques d'Alltrades
wrote:

The message
from "David Hill" contains these
words:

I am thinking of having 2 rows of 4 x 9 x 18 inch blocks with 4 inch
perforated drainage pipe as ducting between them then toped of with 2in
stone to fill the top 5 inch, poss. with slate or something as a toping.
The idea is that the hot air from the top of the tunnel will be blown
through the ducting all day heating the stone and blocks which will then
give of the heat through the night at floor level below the benches.
I don't know if it will work, but I have seen heat sinks used that are pits
around 2 to 3 ft deep filled with 6 inch cobble stones that are heated
through the day by the hot air from the top of a glasshouse.

Thanks for the thermostat ideas, I'll look into them

If you can afford it you'd do better to have several interconnected
plastic drums well buried under the greenhouse beds and filled with
water. A copper pipe riser to the top of the greenhouse, along the
top/ridge, and back down to the far end of the drums, and a thermostat
on the pipe so that when it reaches a preset temperature it starts a
small central-heating pump.

That way you can have warm beds heating the air in the greenhouse during
the nights.

.... and then there are real heat pumps. A heat pump expert I worked
with assured me, that I could heat my house by extracting heat through
the living room wall, that I share with a neighbour, the only snag was
that it might cause frost to form on their side of the wall. He also
developed a heating system that ran on a solution of old engine oil
and water emulsified with a second hand Dutch mayonnaise machine. A
large church in Haarlem was heated this way, parishioners brought old
engine oil to church with them. Sadly burning old engine oil is
illegal here now.
--

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