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Posted to uk.d-i-y
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adding radiator to outside utillity room
Andy Hall wrote:
On 2006-09-17 20:30:06 +0100, "Staffbull" said:
wrote:
Staffbull wrote:
Use a heat exchangeer and antifreeze, or maybe one can put antifreeze
in the main system - I dont know bout that. Use a separate control cct
for the doggery, and insulate the kennel/outhouse.
Letting the dog live indoors would seem more sensible...
NT
I might go for the heat exchanger idea, I'd need to thing about pumping
and switching.
That's easy.
If you have power at the outhouse, you can fit pump and a thermostat
there which just runs the pump. Then at the house end fit a flow
switch on the secondary circuit to detect the pump running. The flow
switch opens a zone valve on the CH circuit which feeds heating primary
water to the heat exchanger.
If there is no power at the outhouse, then you could run wiring for the
thermostat or alternatively use a wireless type with receiver and all
electrical bits in the house.
If the outhouse is fairly small, you won't need a large heat exchanger.
For my workshop, which needs about 4kW, post Celotex, I provisioned
8kW of radiator capacity (IIRC) and used a 100kW heat exchanger because
it was commonly available for use in heatbanks. A smaller one would
have been fine I am sure in this application, but were more expensive.
Bob ( 7 yr ols stafford) prefers living "outdoors" he's
got his dogflap in the utility room and can come and go as he pleases,
I wouldnt put a dogflap in the house as most of the heat would escape
in the kitchen. Kingspan is already in the garage ready to insulate the
utility but I need heat to begin with to warm it up! how effective are
the "low cost" electric heaters? and how costly?
This is really a trade off between capital cost - I reckon about £150
for heat exchanger, pump and controls (possibly a bit less) vs. buying
an electric heater for about £30 and running it on electricity at three
times the price of gas.
I took a long term view and went for the heat exchanger.
You can calculate the heatloss through the Celotex. Strictly
speaking, one should take the U value of each component of a wall or
roof, take the reciprocals, add these and take the reciprocal of the
result to determine a combined U value. Even more strictly
speaking, one should take into account surface effects etc. as well,
but these are minor. Unless the walls and roof are fairly well
insulated already, the U value of the Celotex is dominant and will only
give a slightly pessimistic view of heat loss.
On the Celotex site, you can get the U value for the thickness you are
using (or take 1/R value).
Let's say that you want the interior to be at 16 degrees inside when
outside is -3 degrees, the temperature gradient is 19 degrees.
Measure the areas in square metres and multiply by U value and
temperature difference to give the heat loss in watts. Add all these
up and you will get a minimum value for the heat requirement.
This will give you the information for sizing an electric heater or a
radiator and allow you to do the cost comparison. Obviously you will
have to consider the timescale that you want to use for that.
Cheers, I think I'll go for the heat exchanger method, the utilliy room
is only 2m X 3.5m so not a large area to heat.
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