Has anyone investigated these things

[johnjessop46]

Are the claims substantiated and if so what are the economics

Being cynical I'm of the school of thought "if it sounds too good to be true it probably isn't"

[Tim Watts]

It's a micro-CHP (combined heat power) so it's not "magical" in that sense. Imperial College have a large CHP which generates a fraction of their electricity (a load which is measured in many megawatts).

In the larger forms, there's a certain amount of logic - primarily generate electricity from gas, then use the waste heat for heating.

In micro forms, I'm not so sure - multiply by 1000's like solar panels and instead of steam driving a turbine alternator linked via extremely efficient and long lived transformers to the grid, you have 1000s of inverters (or if the source were AC, some sort of matching/interface device full of electronics) with limited livespans.

The Flow directly driving an alternator that small at 50Hz seems unlikely.

You have another factor that tiny boilers are extremely efficient so there's little waste heat, so the idea of diverting some of that to generate electricity just so you consume more gas does seem a bit strange, except that gas is 1/2 or less the price of day time electricity.

The question here is "how efficient is the gas to electricity conversion?" - If it's not better than 50% you're not really winning.

[Syd Rumpo]

Well any inefficiency is heat, which you want anyway. I expect they're not cheap though, so would take a long time to break even.

Cheers

[David]

In the depths of winter, any spare heat can reduce the need for other sources of heating.

However if your electricity demand in the summer is such that you generate more heat than you need for the house and stored water then you have to either get your electricity from the grid, or throw the waste heat away (which must skew the economics).

One obvious case to consider is if you are in a heat wave and need to turn the air conditioning on.

Cheers

Dave R

[harry]

The Titanic had a similar system running on steam, so not new technology. Been done on industrial scale for a hundred years. Basically turning cheap energy (gas) into expensive energy (electricity). Whether it's economical or not is down to it's lifespan and repair/maintenence costs. The technology doesn't lend itself to scaling down really, (too complex). As others have said not going to be worthwhile in Summer. There's other makers too. EG.

General principles.

[The Natural Philosopher]

the only time that solar panels actually make sense ;-)

[GB]

It's effectively 100% efficient at creating electricity. There's some waste heat from the gas burning, but that's the case in all boilers. This one claims to be 92% efficient IIRC.

The inefficiency in power stations is due to the laws of thermodynamics, and the requirement to lose some of the energy in low temperature waste heat. This set-up does not have that, as all that waste heat is used to heat the house.

The point is that you'd only run it when you want to heat the house or hot water. Then, the electricity generated is a bonus, as it's electrical power at gas prices.

I doubt you'd run it much during the summer, so you'd buy your electricity from the grid in the usual way.

You would only run the boiler to heat the hot water in those circs.

[Johnny B Good]

Is the correct answer. Even better if you're allowed to export any surplus back to the grid which would probably appreciate the extra supply during the high demand winter season.

Is also the correct answer. :-)

The primary function of home micro cph is the heating function with ludicrously cheap electricity thrown in as an effective energy cost reduction bonus. Plus, with a suitable surplus heat energy dumping feature thrown in, you have an effective emergency standby generator.

The only major downside being the need to accommodate a micro chp 'boiler unit' that'll be significantly larger than even a floor standing cast iron boiler of 3 or 4 decades vintage. For decent quiet efficiency you'd need at least a 1 litre 4 cylinder 4 stroke engine running at around a 1000 to no more than 1500 rpm to drive an 8 to 10 KVA generator head running in a suitably designed acoustic enclosure. Even mass produced, such micro chp solutions aren't going to be particularly cheap.

However, with suitable government subsidies, it could represent a 'green solution' to mitigate the self inflicted lack of winter margins on the UK's energy supplies by making more efficient use of our natural gas supply.

OTOH, massive blackouts during the next winter may be the only way to debunk the myth of "Renewable Energy" and get the nuclear power station building program back on track so I rather doubt we'll see any such subsidies. :-)

When words of reason alone fail to convince the idiots, you simply need a bigger "Clue by Four" to knock some sense into their extremely thick skulls. I should think massive power cuts next winter ought to do the trick.