Just came across the thing looking for info on the Fiat ToTem, Total Energy Management which apparently went out of production 1985.
Eco Gen case studies all seem to date from mid 2000s, is it just a cash back con that worked when feedin tariff made it a cash machine or is there any real mileage in micro CHP in general?
The problem with all CHP is that it's uneconomic to run when you have no use
for the heat generated.
About 25% of the incoming energy isconverted to electricity and 75% is
converted to heat.
CHP installations are sized according to heat needs.
Domestically In Summer apart from a little domestic hot water, heat needs
Even in Winter heat needs average less than three or four Kw.
So for domestic use, a non-starter especially when you look at the cost of
Even industrially there are few places for them.
Laundrys used to use them, (lots of hot water needed) but the new yechnology
in laundrys renders them largely redundant there too.
If you don't need the waste heat and even if you do then you use adsorption
There are a number of industrial and commercial CHP installations in the UK
doing just that, reliable self generated electricity, heat and cooling.
On Monday, March 2, 2015 at 10:25:22 PM UTC, The Other Mike wrote:
Thanks Harry and Mike, thought came up in conversation about `green` festivals where bio-diesel and solar panels are de rigeur and its all about being ,er, carbon neutral. ( leaving out manufacturing overhead of some green tech)
One company overhauled an older genset and have plumbed a heat exchanger in for heating production portakabins, this being presented as cutting edge research and proof of enviromental credentials. Someone suggested also using waste heat for shower heating.
Remember Fiat ToTems powering circuit tent at Edinburgh fringe in mid 80`s , late August in Edinburgh ain`t that warm in the evening and they seemed to work a treat, 127 engine with alternator and heat recovery
Heard of gas turbines being used as back up CHP in large buildings 1MW+ level, CHP is apparently Cogenertaion, Combined heat power and cooling CHPC is Trigeneration and add carbon recovery from the exhaust becomes Quadgeneration.
Don`t get mini versions though, gas transmission seems a whole lot less lossy than electrcity distribution....
Seen that too. Didn't work in practice. I saw a seven year old installation
removed and conventional AC installed,
Far cheaper to run.
It all can down to too many heat losses in the end.
Not to mention the capital costs.
Adsorption cooling is very inefficient, costly and huge compared with
So, don't even think about it. If you are,
Also, the whole system was impossible to cntrol/.balance. They spent years
Not efficiently/efectively. They were sold a pup..
There is no such thing as "back up CHP". If you have CHP you need to run it
as long as possible to get the money back. But very few places need the
heat. Even less heat needed now due to improved insulation on buildings.
As with all micropower generation, the power is used locally, transmission
losses are minimal/reduced.
The problem will be one of conrolling them all as they become more numerous.
Every house needs to become a generator.
This is where the smart grid will come in.
Converting ICEs to CHP is an expensive business.
I ran industrial CHP and saw others a while back In large hospitals). Even
at that scale the economics were very dodgy.
Bio diesel is pretty dodgy too. Things don't make a lot of sense if
everything is taken into account.
Depends how small you need, Capstone produce gas turbines units from 30kWe to
200kWe with flexible fuelling, electrical output being about 25% of the
calorific value of the fuel input.
P.S. Unlike what Harry says adsorption cooling does work if it is engineered
On Wed, 04 Mar 2015 11:34:55 +0000, The Other Mike
I think the comparison is distorted by the fact that it's a reference
to 'energy' transmission where the KWH equivilent of the heat produced
by burning the delivered gas is used.
IOW, if you're considering the most efficient way of transmitting
energy used purely for generating heat (excluding heatpumps in the
electrical case), the gas supply uses a lower fraction of the
delivered heat energy than does the equivilent electricity case.
That strikes me as being an unusually modest conversion efficiency
considering that an efficient petroleum/gasoline 4 stroke engine can
manage something like 22% (or maybe as much as 25%) conversion
efficiency. Obviously the small 3 to 5% losses in a decently designed
alternator will add to the overall losses perhaps making the 4 stroke
petrol engine driven case more like 20%. Also, ISTR reading about
diesel engine efficiencies getting as high as 40% somewhere or other
(but I could be mis-remembering this 'fact'). The key figure of gas
turbine efficiency in my mind is something in the region of 30 to 33%.
Again I could be mis-remembering this or, more probably, it's the
figures achievable at large scales in power station turbines.
I think most of us here take such statements by Harry as being
'completely wrong'. It's the default perception of whatever Harry has
to say about _anything_ ! :-)
Remembering this thread, I asked about them at Ecobuild 2015 exhibition
last week. Answer was that they aren't viable on domestic situations.
The smallest one currently made would be the right size for a large
house with heated swimming pool.
[email address is not usable -- followup in the newsgroup]
On Sunday, March 8, 2015 at 11:17:22 AM UTC, Andrew Gabriel wrote:
Thanks Andrew, everyone seems to have had a go at CHP but unfortunately, and suprisingly, Harry seems to be right , the economics never stack up.
Edison 1892 D.C. power stations used waste heat as district heating, cant work out quite where the economics are in the New York Steam System, mid 1920`s Battersea Power Station had district heating for Dolphin Court, Fiat ToTem 80`s
Perhaps its like some sort of perpetual motion machine, or windpower, seems attractive but isn`t really practical.
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