Talking recently to a supplier of gasifying log boilers about heating
options for a detached annexe (sandstone barn) which I've been
converting for part-time occupation, they came up with the suggestion
that I could run both heating and water circuits from a combined
heating system which would use the existing 90,000 BTU oil boiler as
backup.

That sounded a good idea to me, given the savings I could expect on not
having to install a separate heating system and having a renewable and
cheaper fuel source for both. The existing boiler is more than adequate
for heating the main 2 bed house and ultimately, I'd replace it with a
higher efficiency device.

The log boiler will add a minimum 25KW to my total existing heating
capacity, with the barn requiring only 12-15 KW.

I've got to dig up the garden anyway to lay the cold water supply along
the same route , so I guess if there's a type of insulated heating pipe
that could go in alongside that would be ideal. Perhaps I might also be
able to deploy a heat exchanger/thermal store to deliver potable hot
water?

Could anyone advise on where I might look for the kind of pipe I'd need
to use?

Jeff

"Jeff Mowatt" wrote in message
oups.com...
Talking recently to a supplier of gasifying log boilers about heating
options for a detached annexe (sandstone barn) which I've been
converting for part-time occupation, they came up with the suggestion
that I could run both heating and water circuits from a combined
heating system which would use the existing 90,000 BTU oil boiler as
backup.

That sounded a good idea to me, given the savings I could expect on not
having to install a separate heating system and having a renewable and
cheaper fuel source for both. The existing boiler is more than adequate
for heating the main 2 bed house and ultimately, I'd replace it with a
higher efficiency device.

The log boiler will add a minimum 25KW to my total existing heating
capacity, with the barn requiring only 12-15 KW.

I've got to dig up the garden anyway to lay the cold water supply along
the same route , so I guess if there's a type of insulated heating pipe
that could go in alongside that would be ideal. Perhaps I might also be
able to deploy a heat exchanger/thermal store to deliver potable hot
water?

Could anyone advise on where I might look for the kind of pipe I'd need
to use?

Jeff

==================
I don't know of any particular source but you might try 'googling' for
'district heating' which seems to achieve what you're looking for, although
on a much larger scale.

Cic.


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Ah yes, that did the trick thanks Cicero.

I came across something quite interesting in Poland which looks like a
massive investment in this technology.

http://www.ebrd.com/projects/psd/psd2005/35540.htm

It looks a bit tidier than a lot of Eastern European district heating
systems where a "goalpost" bend in the pipe indicates an entrance;-)

Cicero wrote:


==================
I don't know of any particular source but you might try 'googling' for
'district heating' which seems to achieve what you're looking for, although
on a much larger scale.

Cic.


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It has removed 262 spam emails to date.
Paying users do not have this message in their emails.
Try SPAMfighter for free now!

"Jeff Mowatt" wrote in message
oups.com...
Ah yes, that did the trick thanks Cicero.

I came across something quite interesting in Poland which looks like a
massive investment in this technology.

http://www.ebrd.com/projects/psd/psd2005/35540.htm

It looks a bit tidier than a lot of Eastern European district heating
systems where a "goalpost" bend in the pipe indicates an entrance;-)

Cicero wrote:


==================
I don't know of any particular source but you might try 'googling' for
'district heating' which seems to achieve what you're looking for,
although
on a much larger scale.

Cic.


======================
I think you'll find other examples much closer to home, which is the reason
I'm aware of the idea.

One item that caught my attention in the Polish example is the statement the
no asbestos is used in the pipe lagging. Presumably they're using something
with similar properties without the attendant danger of asbestos so if you
can find out what they are using that would give you some idea of what you
could use to lag your pipework.

Cic.


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I've got to dig up the garden anyway to lay the cold water supply along
the same route , so I guess if there's a type of insulated heating pipe
that could go in alongside that would be ideal. Perhaps I might also be
able to deploy a heat exchanger/thermal store to deliver potable hot
water?

Try and get hold of Andy Hall. He ran a similar system to his shed, isolated
from the main system using plate heat exchangers to reduce leakage and
draining issues. You may find a description with judicious use of Google
Groups.

Christian.

On 2006-08-17 10:17:57 +0100, "Christian McArdle"
said:

I've got to dig up the garden anyway to lay the cold water supply along
the same route , so I guess if there's a type of insulated heating pipe
that could go in alongside that would be ideal. Perhaps I might also be
able to deploy a heat exchanger/thermal store to deliver potable hot
water?

Try and get hold of Andy Hall. He ran a similar system to his shed,
isolated from the main system using plate heat exchangers to reduce
leakage and draining issues. You may find a description with judicious
use of Google Groups.

Christian.

It's a workshop, and the story runs thus:

- Basic construction is single brick, tiled and felted roof etc. In
the winter, this would require about 10kW of fan heater for some time
to make it warm enough to want to work in it (i.e. 12 degrees plus.)
It took ages to warm up. Expensive and not practical.

- First step was to insulate the whole thing with 50mm Celotex. This
brought the heat requirement down to around 4kW to provide 18 degrees
ambient in cold weather. Not bad but I wanted to reduce the cost and
not use electric heating.

- One option which was ruled out was a separate boiler. Cost of
laying on gas service made no sense.

- The other, was to use the house heating system to provide heat for
the workshop, so I researched that.

There were a few design criteria:

+ Simple to add to existing system

+ No requirement for electrical connection between the buildings

+ Failure in the workshop system of any kind should not compromise the
house system

+ Exterior heatloss should be minimised

+ Minimal risk of freezing.


Putting these together mandated a secondary circuit heated by the
boiler primary. A stainless steel plate heat exchanger of 200kW
rating is used. Although the load is nothing close to this, it
minimises the temperature drop to the secondary circuit.

The secondary circuit is filled with a fairly concentrated mixture of
Fernox Alphi 11. This is a corrosion inhibitor and anti freeze.
Since it is relatively expensive, only using it in the secondary
circuit saves the cost of filling the entire system. The secondary
circuit is run sealed and pressurised and filled via filling loop as
normal. Any failure in this circuit - bursts, leaks, freezing
(unlikely) does not compromise the house system.

Control is achieved by having a timer/thermostat in the workshop
operating a pump. In the house, there is a flow sensor in the
secondary circuit. When the secondary water flows, this switch closes
and operates a zone valve feeding the primary side of the heat
exchanger. That in turn fires up the boiler.

Pipework is plastic barrier insulated in thick Armaflex. This is
taped and fed through large diameter soil pipe running between the two
buildings and buried. I've measured the pipe temperatures in steady
state condition on a cold day and there is no measurable temperature
drop on a 15m length of this, so I believe that any heat loss is not
substantial.

The radiators in the workshop are deliberately over provisioned so
that the room is warmed rapidly.

The same principle is used for pool and spa heating, so it's
generically useful.

There's no reason why it can't easily be adapted to heat a complete
house and HW system remotely. In effect the heat exchanger is a heat
source like a boiler and can be turned on and off based on heat
requirement at the remote end.