in operation, or is planning on building one?
its time we did a little refocusing on our forum get start working on what we are all about.
there are many members that have no use for cogeneration, and that is ok.
there are also many members that are working on various aspects of cogeneration and it is time
we explore what our members have going on.
so lets hear what you guys have going on with your cogenerators or cogen plans
admin
At this exact moment.... I don't have any cogen. However, at some point in the future, I anticipate living off-grid running 1 or 2 veg-oil powered Lister CS engines with alternators/dynamos of some description. Waste heat will be used to provide domestic hot water.
One engine will be used to run a workshop, whether by electricity generation or line shafting, I've not yet decided.
Since I plan to live in a warm sunny place, I will certainly be looking at solar hot water, and may investigate PV solar as well. Depending on practicality, time & money, I'd like to look at stored hydro as an alternative to a battery bank; but ultimately, that may not be possible.
The money I'm earmarking for this project will be sufficient to buy a decent sized spread (maybe up to 8 hectares, about 20 acres) with enough left over to renovate a ruined property. With 20 acres, I can grow my own firewood, and olives (to replace diesel fuel); so, in theory, I could be fuel independent. In practice... well, so long as I can get close, that'll be good enough for me.
I'm on it. At this time we provide all electricity, most of our domestic hot water, and all our hot water floor heat from the generator. This runs off of waste ATF soon to be converted to WVO.
We have solar and wind projects in the making, still planning.
The house is a "Berm" house build into a south facing slope so we get a lot of passive solar heat.
Other then fighting to keep the generator running life is simple.
Ken Gardner
Very small room, probably a cellar or coal storage. Found any traces of coal chute?
Cheers, Wizard
The house is not old enough for a coal furnace and this "bunker" is on the wrong side of the basement. The top was completely sealed until I cut a hole in it to load firewood. I put a wood stove and chimney on that end of the basement when I first moved in. This wood stove will be incorporated into the cogen system one day. I have a design in my head for a heat-ex in the stovepipe where it exits the stove.
A cool, food storage area is the only purpose I can think of but the house just isn't that old.
Thanks, Geno
Will I've got plans for co-gen. We're off grid and using a 6/1 roid for back up power. There are 600' hydronic tubes under the insulated basement floor. I just need to figure out how to get the hot water into the house and circulate it through the floor.
i know there has to be more "cogen-anator's" in this group!
plus one with me, s195 idi changfa based
its been a long journey, and actually i think i am glad it has taken to long
the overall efficiency has improved dramatically over what it would have been had i
went with the first version.
currently i am working on a theory of operation that is a departure from anything i have considered before
and have not seen anyone else consider.
still working on it, but i have to draw this to a conclusion in the next few months, time is drawing near for me
needing it to do what it was designed to do.
bob g
Yes count me in to. I have a 10/1 Omega that I run on WMO that is used to heat a farm shop, have plans to route the elect power into my house for heat in there but for now it is just used in the shop for more heat. The hot water it makes goes in to in floor heating, 4000+ feet of pex tubing. Got to get a better heat exchanger built for the engines exhaust, the 1st was too quick to plug the one I am using now is too inefficient and wastes heat. But it never plugs!
Billswan
I'm going to tap my 10/1 into my hot water system with a heat exchanger. The main goal is simply backup power, but I'll be evaluating how well it does everything.
Folks,
Well, I've got a Metro 6/1 and I'm well on my way to getting the co-gen running.
I'll be heating the house and hot water in the winter and hot water and perhaps air conditioning in the summer.
I don't have a battery bank and don't plan on getting one.
I'm considered using a primitive load shedding/sharing system run by a microcomputer.
I need to finish up what I've started first though.
Now that the nice weather is here I've started working again...
Crumpite
I've got a 6/1 'roid that lives on a anti-vibe mount in my basement. (yea, I know, a really bad idea for lots of reasons - perpetual bachelor-hood not the least of them - but it starts real easy when it's frigid outside and I'm getting lots of radiant heat from it too) Exhaust heat is extracted with a heat exchanger and routed to a motorcycle radiator with a fan, and the cooling system feeds a cast iron radiator upstairs. The house is passive solar heated and solar powered so the set-up is a nice addition on cloudy days when the batteries need charging.
Bill
It doesn't look like cogen is in our near-term future. We just started working architect Debbie Coleman (author of Sun Inspired House) on our future passive solar retirement home.
http://www.sunplans.com/learn/sun-inspired
The single level house will be 1480 sq feet and one bedroom. The separate garage/shop will be 1250 sq ft and will also have 400 sq feet detached living space (great room, one bedroom and bathroom).
The passive solar should provide nearly 70% of our heating needs. We will use a masonry heater to supplement the passive solar and to create a nice atmosphere in the evenings. We have plenty of timber on our property. Masonry heaters are much more efficient than wood stoves and provide a gentle and even heat transfer (i.e., you only have to fire them up for a couple hours and they will radiate even heat for couple days). We will also use hydronic radiant heat flooring via propane boiler to supplement the passive solar. We really prefer to cook on a gas stove/oven and we want to avoid the high electrical load requirements that an electric stove/oven would create. Given that we will need propane for the stove/oven, figured might as well use it for the supplemental radiant heat flooring and hot water heater too. This could be perhaps where cogen or solar water could be taken advantage in our long-term future. However, we would prefer not to create any noise by running an engine unless it was absolutely necessary. Primary electrical power source will be micro hydro. Backup electrical power sources will be the 6/1 and the grid.
Bob B.
I recently encountered a problem with Cogen. The generator is a Northern Lights 9kW Northern lights genset detuned to 7kW by running as a 50HZ genset putting out 230v
The Norther light engineering department flatly declared we could not draw off any heat from the genset via heat exchangers since this would cool off the genset to much and cause it to run badly.
The plan was to use air handlers and Red Dot radiators in living quarters. Total floor area is approximately 650 squarre feet This is likwely not going to encounter below freezing temps so heating load is not that great. So why would Northern Light declare this cannot be done and is technically impossible?
Personally I think they are wrong but what do I know?I dont have an engimeneering degree paper. :(
the only thing i can think of is the generator has no thermostat, or they were afraid you would take the heat off the block
like cars to for the cab heater. under such use it is possible to overcool the engine and in doing so the engine will start to smoke
pollute and coke/gum up quickly.
now if you use a heat exchanger and a pump that has a temp switch control so that the pump shuts off if the engine coolant temp gets below
perhaps 180 degrees F, then you should be good to go and cannot overcool the engine.
there are other methods as well, such as setting up a bypass for the engine radiator loop, and divert that duty to your red dot heater in the house
then the engine can still maintain the needed heat level controlled by the thermostat.
i understand their concerns, but it can be done correctly, just as it can be done incorrectly.
bob g
Hi Enlav,
Look at the respective Volvo's.. the NL 4.5 - 8kw use the same perky\cat/volvo (Shibara) engine volvo Marine offers a heater connection kit...they take the heat only above the t-stat, so it can't rob the engine, when the t-stat is closed.
Lloyd
"the only thing i can think of is the generator has no thermostat, or they were afraid you would take the heat off the block like cars to for the cab heater. under such use it is possible to overcool the engine and in doing so the engine will start to smoke
pollute and coke/gum up quickly".
That is what I was figuring so I wrote back explaining how we planned to use a heat exchanger and separate circulation pump. My guess is, it's a knee jerk reaction by a manufacturer who has to ensure their engines are Type III compliant and thus they cannot knowingly advise on something that might cause the engine to run outside the EPA mandated envelope.
The joke being this engine was shipped from Seattle to China for installation and the boat will cruise away from North American or European ports for the next five to ten years.
In other words it will not even be in any place where air pollution is taken seriously.
The expected cooling load for the boat is about 26,000 BTU or maybe 30,000 BTU. I estimate we would not be close to that for heating the same volume . So how many BTU of heat could I reasonably expect per HP developed in the generator engine?
Never ask the factory what can be done- they'll fall back to the specs and never deviate because anything they say can and will be used against them. They feel that the system dissipates heat well enough on its own, and that a modification to harvest that heat can damage the machine by taking more heat than the cooling system was designed to dump. They know what happens next- "but Joe in your engineering department said it would be fine!"
Ask something specific that they can tell you without leaving their asses hanging out- like what temperature range the coolant return should be. That and flow rate are all that the engine cares about. For what it's worth, I'm not an engineer either.
My system will go to a heat exchanger, with a shorter cutoff loop using a temperature control valve. I haven't gone looking for said valve yet, but that's the plan.
roughly speaking the following will give you an approximate value to answer your question
1kwatt = 3415btu's
so for each kwatt mechanical produced, the engine will dissipate approx 3415 btu's from the coolant and roughly the same
for the exhaust. the actual numbers will be about 3kbtu for cooling and 3kbtu for the exhaust for each kwatt of mechanical load
on the engine, the difference will be windage, radiation, vibration, noise and other minor losses.
so if you load the engine to 5kwatts electrical and maintain it there, and assume the generator is 80% efficient, the actual mechanical
load will be approx 5000 / .80 = 6250 watts mechanical load on the engine, so lets round it to 6kwatt mechanical
6000 x 3000btu = 18000 btus from the coolant and the same from the exhaust, is pretty close
therefore, 18kbtu + 18kbtu = 36kbtu available from both sources for harvest
i figure a recovery of approx 75% of that is attainable, so 36kbtu x .75 = 27kbtu's at 5kwatts electrical load
of course more load will produce more available and recovered heat from both sources, and conversely less load will reduce the available
and recoverable heat.
i think you will find my numbers are pretty close
bob g
Thank you, Bob.
That was the single most useful thing I've learned since August, when a friend explained his 6/1 to me. Usually you're talking over my head, and that'll probably never stop- but today you helped me a lot.
Take care.
-Ryan
Bob...
I'm sure your numbers are about as close as anyone will get. The fly in Enlav's case is that the NL is seawater cooled in a manicooler, so it will rob most of the recoverable heat, unless a bypass of the mani is set up.
I have been thinking about this issue, If I set up a seawater bypass of the mani, then I have no water to dump in the exhaxust. The connection between the mani and the exhaust elbo there is no room to set up a parallel bypass to feed just seawater to the exhaust. So I think, that the recovery will be scant.
So that leaves a bypass on the engine coolant side, which is ported to the mani, so that foils that plan. i think, it could supply domestic HW...but I'm not sure it could support cabin heat.
Lloyd
i keep forgetting about those pesky marine watercooled manifolds, but
i suspect a good exchanger might get some heat, although not nearly what it would get without the
water jacketed manifold
if elnav could get a temp reading from right at the outlet of the manifold at 5kwatt electrical load
with seawater cooling of the manifold i think i could get a pretty good estimate as to how many btu's he has
left to take a run at harvesting.
that is unless the exhaust exits with the salt water waste from the manifold jacket, in which case there is nothing
i would want to try and harvest.
bob g
Quote from: mobile_bob on April 21, 2010, 11:18:09 PM
i keep forgetting about those pesky marine watercooled manifolds, but
i suspect a good exchanger might get some heat, although not nearly what it would get without the
water jacketed manifold
if elnav could get a temp reading from right at the outlet of the manifold at 5kwatt electrical load
with seawater cooling of the manifold i think i could get a pretty good estimate as to how many btu's he has
left to take a run at harvesting.
that is unless the exhaust exits with the salt water waste from the manifold jacket, in which case there is nothing
i would want to try and harvest.
bob g
yea Bob,
That is the issue, the tube bundle is floating so to speak in the the engine coolant, the engine coolant is ported to the block, into the manicooler, the Tstat is in in-between, so to stay above the Tstat you have to take the HW from the mani, and return through the pump.
The seawater is already harvesting most of that heat, if you take supply of HW from the block or the head you're bypassing the Tstat, and run the risk of over cooling the engine.
The mani dumps into the exhaust elbo in a 90. That requires you to fit the pre-made 90 hose as you fit the elbo to the mani...there is no way to replace the hose with-out removal of the elbo.
My guess would be to add a three phase tap to a storage tank with a three phase immersion heater, at least that way you would be able to run heat when the gen is lightly loaded and increase the total efficiency of what is typically an over sized Prime Power AC.
Lloyd
Quote from: mobile_bob on April 21, 2010, 11:18:09 PM
i keep forgetting about those pesky marine watercooled manifolds, but
bob g
That pesky mani can be a landlubbers friend applied to a co-gen...probably the most efficient way to recover the waste heat from both the exhaust and the radiator.
Lloyd
Lloyd, This is what I am accustomed to seeing in West coast boats. I can only surmise the builder is playing CYA and the chinese yard is playing dumb. Neither is willing to say yes meaning if we design something and the yard screws up, the blame falls on the owner who asked for the mod and myself.
My past exxperience with chinese yards is not encouraging. The level of technical savvy is deplorable.
If I specify a 15 amp breaker they ask what size wire gage. Duh! They musxt have familiarity with 16A breakers since this is one of the standard sizes they use over there but they dont know what wire to use.
I once looked up the correct John Deere part number for a cast alternator bracket and verified all 6068 engine blocks were drilled to mount this bracket. The chinese yard came back saying it doesn't exist.
And so it goes.
FWIW: For available heat, I have measured 16,200 BTU/HR out thru my cooling system heatexchanger with a 3KW electric load. That was a measured 3/4 GPM(6LB of water/min) raised from 77F to 122F(45F increase) That is about 5400 BTU/HR per KW of electric load on the generator... It was also right in line with the rule of thirds. At that load I was burning a little less than 1/8gallon of fuel per hour, or about 50000 BTU worth of fuel. 1/3 of that fuel burnt is 16600 BTU...
YMMV.
Thanks guys for a lot of useful information. I now see the problem in a better perspective. Given the difficulty in communicating with a chinese boat building yard where the only english speaking person is a lady in the office who has no technical expertise and technical workers who can neither read, write or speak even one word of english I think this option is effectively excluded for this boat. However, the subject is definitely on the list of possible options for the future.
Being a newbie I have a dumb question. Has anyone been able to make a workable heat recovery system for an air cooled engine. Every configuration I think of soon reveals its flaws. Having been nearly killed by a VW car heater system I am extremely leery but maybe there s a solution that had not been hought of back in 1980
Enlav,
if you can shroud the air cooling fins of the block/head...you could then adapt a air to water heat/x for the recovery without asphyxiation..
just a though
lloyd
Lloyd wrote:
Quote
if you can shroud the air cooling fins of the block/head...you could then adapt a air to water heat/x for the recovery without asphyxiation..
That is exactly what Volkswagen did in their old air cooled motors and that is what almost killed me with CO poisoning on a long drive. Fortunately a mechanic recognized the symptoms before it was too late. Most people might have mistaken the problem as being drunk. I was once left lying near unconscious in a snow bank after suffering a similar problem in another vehicle. Needless to say I have little confidence this approach is safe or fool proof.
Enlav,
I think you misunderstood, there would never be any co as the it is seperate, the water can't carry co to the...you would be heating the water and then using the hw for domestic heat...I think the old vw's used air to air...just like the old Chev Corvair's.
Lloyd
Right you are but how to make that shroud is still the challenge. Getting a liquid tight fit is just as bad if not worse than getting an air tight seal. Fischer Panda engineered a liquid cooled generator and had nothing but problemns due to leaks. The original air cooled genset was fine but converting it to liquid cooled evidently proved a real challenge.
I suppose you could blow the air past the fins then through a radiator for heat transfer in reverse. Somehow it intuitively doesn't seem to be as efficient as having the cooling liquid directly in contact with the finned cylinder head. Maybe the fins need to be cut back to give better welding surface.
All right you two, Lloyd and Elnav, the VW heater uses fresh air drawn in by the cooling fan, forced through a paper/foil tube then into
an exhaust heat exchanger complete with dampers that are cable operated, then into the cabin of the car.
No actual engine or cylinder head heat is used, just exhaust. Not the safest system in the world.
Elnav, your Guardian Angel was watching!
Ron
QuoteElnav, your Guardian Angel was watching!
Ron
Amen to that! By now I have outlived the proverbial cat with nine lives. But that is anudder story. :)
Hey Ron...
That's what I said
Quote from: Lloyd on May 03, 2010, 12:48:51 PM
Enlav,
I think you misunderstood, there would never be any co as the it is seperate, the water can't carry co to the...you would be heating the water and then using the hw for domestic heat...I think the old vw's used air to air...just like the old Chev Corvair's.
Lloyd
I just forgot to say air to air heatX, as that's what we were talking about.
Enlav,
You must be familiar with an air to water heatX as used in marine refrigeration, those units can be pretty effective...so you just need shroud the engine in a well insulated...could be a well insulated sound shield, add an air intake and a outlet, place the air to water heatX at the outlet w/a fan to draw air through the finned-tube heatX...of course it won't be as efficient as a water cooled...but I imagine there is considerable heat to get at.
Lloyd