domestic cogeneration

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would it be economical in some instances to have a cogeneration plant for a residence, using an internal combustion engine? they can be of any common fuel type ie. natural gas, gasoline/petrol and diesel. perhaps even wvo. it's said that they can achieve upwards of ~90% overall system efficiency, comparable to an entry level category IV condensing furnace. since heat is always being generated, it would seem to make better sense for colder climates, with piped natural gas supply and a great contract price. it may not be so bad for hot climates either if waste heat could be used for cooling purposes perhaps via some sort of ammonia refrigeration device or perhaps a standard automotive a/c compressor driven right off the engine- but the latter does not directly harness the wasted heat.

a typical setup
cogeneration-chp-plant_principle.jpg
 
Did the math some years ago for my place...see my Natural Gas thread for why it's no longer viable due to gas prices.

During winter, if I'd run an IC generator on gas, there would be enough low and high grade heat to provide my winter heating and hot water, while offsetting my electricity consumption.

Solar is now under $1,000/KW, so is more likely to attract my money short term.

Currently looking at thermal absorption refrigeration as my mental rabbit hole (google Einstein Fridge, but there's simpler out there), as I'd love waste heat to cool my place.
 
External combustion rather than internal combustion might be better for a heat engine, being fundamentally cleaner. And if you consider carbon footprint in addition to your pocketbook solar is the way to go.
 
We once ran the numbers to see if the swimming pool could be run by the diesel generator (20kW, load is less than half that), and it turned out the answer was no.

The issue in this case is that once the envelope of the home is heated, the system has to dump waste heat elsewhere and then it becomes highly inefficient. The systems and demand need to become large enough that there is always a taker and that the systems can be adjusted and optimized for demand.

FYI in places where diesel is used with gas turbines to provide electricity and the heat is used to distill water as a side product, electricity is still around 50c/kWh.
 
I saw at a Lab, they had what looked like a refrigerator with an air cooled NG 12kW engine, waste heat off the engine was ducted into the building. Would basically provide base load for a small house and some heating.

CoGen in the US is basically dead with RICE NESHAP.
 
Can't seem to get to it, but google up "spark spread estimator" and you will get to the Dept. of energy web-based calculator. Not economic for a house.

There's not enough work being done on district heating and cooling in this country. Very efficient, but the politicians all like to have their pictures taken standing next to a solar array.
 
Originally Posted By: Fraser434
I saw at a Lab, they had what looked like a refrigerator with an air cooled NG 12kW engine, waste heat off the engine was ducted into the building. Would basically provide base load for a small house and some heating.

CoGen in the US is basically dead with RICE NESHAP.


Can get, albeit currently at great cost, a fridge sized fuel cell that does the lot for you as well.
 
I have friends that live 'Off the Grid' they get by quite nicely with wood heat and hot water from an Agga, Solar, a Turgo water turbine and a Kubota Diesel generator.

A Sterling powered generator would be even better.

The trick is, Conserve electricity!

Stay with them a week during the winter, and you get a whole new insight as to how we waste power.
 
Originally Posted By: Shannow
Did the math some years ago for my place...see my Natural Gas thread for why it's no longer viable due to gas prices.

During winter, if I'd run an IC generator on gas, there would be enough low and high grade heat to provide my winter heating and hot water, while offsetting my electricity consumption.

Solar is now under $1,000/KW, so is more likely to attract my money short term.

Currently looking at thermal absorption refrigeration as my mental rabbit hole (google Einstein Fridge, but there's simpler out there), as I'd love waste heat to cool my place.


i saw what they're doing with NG down there, that is insane! we are charged by the cubic meter, the price just spiked from 18.3cents to 20.89 cents/m3, and i thought that was bad. i think that works out to 1.7cents/MJ, so still a deal, relatively.

but we're currently paying 155cent/L for regular petrol (and are trying to pipe alberta crude to the usa and to the coasts- destination china). selling right out seems to be the norm for the commonwealth, innit? 3.6c/MJ for gas would almost be a human rights violation in the frozen wasteland we live in.


electricity: we not only pay for the KWH consumed in a 3-rate pricing structure, but there are a set of standard fees that must be paid, regardless of consumption. the same with the gas bill too. if one of those services could be nixed, we wouldn't have to pay these arbitrary fixed charges.

eg. our gas bill for march 20 - apr 17 is $135.96. of that, we've consumed $46.57 worth of gas.
the rest must be paid, even if we use no gas at all:
Originally Posted By: Enbridge extraneous charges

"Customer Charge" - $20 (great, we have to pay for just being a customer)
"Delivery to you" - $23.40 (because doing virtually nothing to physically move the gas costs each customer that much)
"Transportation to Enbridge" - $15.34 (a second delivery charge)
"Gas supply charge" - $46.57 (actual fuel cost)
and finally
Cost adjustment - $8.92 ????


that's no better than the electricity, though. while it's "relatively" cheap per KWh, still carries fixed charges and is priced according to time of use.

Originally Posted By: Toronto hydro bill, last year 12/19/2012-2/20/2013 a bi-monthly bill period

total bill: $187.79
old rates (they've gone up since);
* 11.8 ¢/kWh Highest Price (On-peak)
* 9.9 ¢/kWh Mid Price (Mid-peak)
* 6.3 ¢/kWh Lowest Price (Off-peak) after 7pm

Real Power consumption - $95.49
Delivery - $72.89
Regulatory - $8.20
Debt retirement charge - $8.21 (not bc we paid late last month, THES charges everyone this fee-- it's their own debt we are absorbing!)

so for electricity, we consumed at that time, at those rates $95.49 worth of juice at a tiered pricing structure.

surely subscribing to these two services, regardless of consumption is an extortionist affair. i'd love to cut one completely off if possible, but having not run all the numbers,
am not sure if it could be economical for us.

in your case, in sunny Australia solar just seems to make the best sense, perhaps even solar water heating. here, every day it seems is overcast. it just seems impossible for a day to go by with clear skies from morning to night- if it starts off clear, it almost certainly gets overcast by days end...................

so how about that absorption refrigeration idea? got any plans
laugh.gif
 
Originally Posted By: JHZR2

The issue in this case is that once the envelope of the home is heated, the system has to dump waste heat elsewhere and then it becomes highly inefficient. The systems and demand need to become large enough that there is always a taker and that the systems can be adjusted and optimized for demand.

FYI in places where diesel is used with gas turbines to provide electricity and the heat is used to distill water as a side product, electricity is still around 50c/kWh.


That's the thing, balancing system output to total energy needs. perhaps a smaller engine would make sense. I was thinking about something of a 10-12kw 1.8L engine at 1800rpm, with a heat buffer storage device of some type. I love the idea of passive water distillation, how awesome would that be on an island or the coast? the price of the fuel does kinda ruin things.
Originally Posted By: expat
I have friends that live 'Off the Grid' they get by quite nicely with wood heat and hot water from an Agga, Solar, a Turgo water turbine and a Kubota Diesel generator.

A Sterling powered generator would be even better.

The trick is, Conserve electricity!

Stay with them a week during the winter, and you get a whole new insight as to how we waste power.


those are very smart ideas to implement
thumbsup2.gif
still interested in looking at a high efficiency wood stove/fireplace, the ones with "EGR" that reburn the flue gasses. they stink much less too!
 
Originally Posted By: JHZR2

The issue in this case is that once the envelope of the home is heated, the system has to dump waste heat elsewhere and then it becomes highly inefficient. The systems and demand need to become large enough that there is always a taker and that the systems can be adjusted and optimized for demand.


I think the answer is to store power in a Battery pack, the unit need not run continuously (other systems, like Solar, could also contribute, to charge the Batteries)

I'm off my Ipad now, so I can now easily Paste the info on the Italian Cogeneration unit:

"The Italian Company, ENERGIA NOVA, manufactures a small
gas engine CHP unit 20 kWe, 47 kWth which is based around
the FIAT FIRE 1200 cc engine. It is rated to have an
impressive 97% overall efficiency (29% electrical, 68%
thermal). Maintenance is recommended every after 1500
hours of operation. One of the selling points advertised for
the unit is the saving of 450gm of CO2 per kWh as well as
lower NOx emissions with a maximum of 60nm3 emitted.
ENERGIA NOVA reports that customers may save up to 40 %
of fuel costs per year with cogeneration. "
 
"those are very smart ideas to implement
thumbsup2.gif
still interested in looking at a high efficiency wood stove/fireplace, the ones with "EGR" that reburn the flue gasses. they stink much less too! [/quote]



A lot can be done with wood stoves, but you soon run up against stove certification/Home insurance.

Even adding a Water heat exchanger will likely void your insurance.

My friends with the Agga effectively have no insurance. Fortunately they DO have commonsense.

There is lots of Power available to us, it's just not always available when we want it.
Storage is Key!
 
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i think what you are trying to do is NOT reinvent the wheel but make the best use of the things we already have. very very smart.
 
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