On 24/04/2017 07:43, harry wrote:
On Sunday, 23 April 2017 21:37:09 UTC+1, Vir Campestris wrote:
On 23/04/2017 08:13, harry wrote:
Higher steam temperatures results in less efficient boilers because the exiting combustion gases can be at no lower temperature than the stem.

This turns out not to be the case.

You can, for example, use the warm exhaust to preheat the incoming air &
fuel.

Andy

The effect is negligible and leads ot all sorts of control problems.
The specific heat of air is low.

What? Are you really trying to suggest the temperature of combustion is
independent of incoming air temperature?

There are even recuperative furnaces for smelting. I suggest you look up
'recovery boiler design' before showing any more ignorance.