DIYbanter - View Single Post

On 1 May 2004 06:05:25 -0700, (N. Thornton) wrote:

It might be possible to have a semi-ground loop. Air would be used
when it's temperature is above 0, and the ground loop at other times.
A smaller pipe in the earth or large pond could be used as the ground
loop.

Also when the air temperature is above that of the ground loop, the
ground loop could be warmed using the air. This could all be done with
a normal outdoor unit with a small pump to circulate liquid warmed by
the ground loop over the coils when required. The liquid could be
distilled water maybe with some potable antifreeze.

extra complication, extra cost, thats the problem.

Not really, apart from a small ground source of some type it just
requires a small pump and some tubing. Rather than use the ground
source to supply all the heat, just use it as a buffer to even out
temperature swings.

This should allow a heat pump to operate more efficiently as the
average monthly winter temperature in the UK rarely drops below 0°C :

http://www.metoffice.com/climate/uk/seriesstatistics/ewtemp.txt

Even the average monthly temperature last summer was 17°C, so it could
be used for air conditioning or even normal air cooling too.

With some simple temperature control on the pump the ground source
could only be used when necessary and it's temperature change reversed
when the air temperature allows.

cheers,
Pete.