On Tue, 21 Sep 2004 18:21:11 +0100, Malcolm Reeves
wrote:

Why not make a stainless flue gas heat exchanger for a conventional
oil boiler, and use the low grade heat for UFH/HRV/DHW
preheat/kickspace heater?

Cos I'd need to convince Building control it was ok and given that
boiler is already about 90% efficient that only leaves 10% to get.
GBP40 pa tops. Not worth the effort. I could probably save more
shopping around for oil, improving insulation etc. It would be a very
risky endeavour with unknown gains.

Hi,

90% is very good for a non condensing boiler, though oil has half the
latent heat losses of natural gas.

One way to do it would be a fan assisted exchanger in parallel with
the flue, then there should be no net effect as the flow is balanced.

I'd expect oil to increase in price over inflation in the next 10
years, this will speed up the payback on any up front investment.

Why? The US is wedded to the car. They drive everywhere and the
layout of their shops support that. If oil was more expensive so
would be US petrol. A much as I think they should pay more for petrol
to cut down their emissions I don't see it happening. Plus the last
time the Arab states hike petrol prices the world went into recession
which hit them too. Now they adopt a balancing act to get the biggest
income, that is the middle ground between cheap oil - large sales and
expensive oil - low sales. So why should oil increase in price? It
might fluctuate some, but that's all.

I think it's their intention to get oil prices lower, but having tax
breaks for unnecessarily large vehicles won't help in the long run.

cheers,
Pete.