On Fri, 13 Nov 2009 10:27:24 +0000 The Natural Philosopher wrote :
efficiency of a heat engine is pretty much down to the ratio of
combustion temperature to exhaust temperature.

That's the rationale behind the condensing boiler.

Surely the rationale of a condensing boiler is that the amount of
heat released when the water in flue gases condenses is vastly
greater than any amount of heat gained by just cooling them a bit.

--
Tony Bryer, Greentram: 'Software to build on' Melbourne, Australia
www.superbeam.co.uk www.superbeam.com www.greentram.com