"Ian Stirling" wrote in message
...
IMM wrote:

"Steve Firth" wrote in message
...
Ian Stirling wrote:

Of course, if you could get small 24*7 generators, doing the CHP
thing and putting the exhaust heat into the house, and the low-grade
residum into the heat source, plus using the shaft power to run a
compressor, then that would pretty much beat anything.

Heh, I'm working on something similar. Generators work best at constant
load so I'm fixing up an immersion heater as a ballast load and
planning
to run the exhaust through a coil in a separate calorifier.

The calorifier will have to be a strong, expensive stainless job. The
exhaust may rot a lesser one very quickly. It will generate much heat
(the
IC engine produces more heat than turning power), so you will require a
vast
amount of hot water storage to make it anywhere near viable.

Conventional IC engines are pretty close to breakeven, if they are
run on cheap fuel, and the result compared to electricity.
If you add in the heating, it can be an overall win.
(neglecting maintainance, and capital costs, which is the biggie.)

The problem with Combined Heat & Power is that it is expensive to run using
even the most economical diesel or natural gas generator. Most of the time
there is little power being
used in a house, with power usage tending to be bursty, yet the unit has to
run in case of demand and to run the numerous times clocks in a house.

The only way to make it feasible is to store the output of the generator in
stored hot water, which requires a "very" large thermal store.

I believe an engine which is a cross between a turbine and an IC engine is
being developed in Holland. The inventors are English. This promises to be
an excellent choice over piston units being initially developed for large
scale CHP applications. The inventors initially developed it for vehicles,
and say it is scalable, as piston engines are, to almost any application.
Fuel consumption in vehicles is predicted to be around 3 times better. So in
10 years you may be getting 120 mpg with vastly reduced emissions in a mid
sized car. or running your house on one. It can run on many fuels, so
natural gas powered and connected to the grid, we need far fewer power
stations.

Insulation is indeed generally easier,
as are many other measures
in general.

It is best to ignore machines and concentrate on the building fabric and use
solar gain. Merely installing highly insulated shutters, that are closed at
night (the Victorians used shutters a lot) can save a hell of a lot of heat
that would normally drift off out into the night via the windows. So solar
gain during the day and keep it in at night. Then there is the security
aspect too.