Capstone Turbine
Capstone Turbine
(OP)
Hello,
Has anyone first hand information regarding this capstone microturbine? I wanted to know if power is generated through inverter to high-speed brushless motor or if is using speed reducer and 3600 rpm genset. Also, what is good/bad about this? (I have downloaded for web a cost analysis for one installation in Canada, but there must be someone else using these...)
Thanks,
Alex
Has anyone first hand information regarding this capstone microturbine? I wanted to know if power is generated through inverter to high-speed brushless motor or if is using speed reducer and 3600 rpm genset. Also, what is good/bad about this? (I have downloaded for web a cost analysis for one installation in Canada, but there must be someone else using these...)
Thanks,
Alex





RE: Capstone Turbine
I've installed them, but never opened the case, sorry.
JTK
RE: Capstone Turbine
RE: Capstone Turbine
RE: Capstone Turbine
RE: Capstone Turbine
I'll have to check on the project...
JTK
RE: Capstone Turbine
I understand these units can be jetted for different fuels, is this something user-changable?
Do you know the difference in the sizes (are turbines different or is only synchronous motor/inverter sized different?) The weight and dimensions listed are too big for me, I have a project requiring a smaller unit (15kW/30kW). I wonder if this equipment is possible to downsize...or split the mounting of several components to better fit my installation.
Thanks fo your comments.
RE: Capstone Turbine
Not sure on the sizes they sell, but I'm sure the website will inform.
RE: Capstone Turbine
RE: Capstone Turbine
The high speed (direct drive) alternator has extremely good power to weight ratio but is expensive, because they are difficult machines to engineer and commission, and the component and assembly costs are high. On top of this of course, the sales volumes are low. They have very high efficiency: 97-98%, including windage losses but not including bearing losses, compared to say 92% for a conventional 30kW generator.
I believe that high speed gearboxes (and we are talking say 80krpm down to 1800rpm) are specials but are available, no personal experience of these. Overall I think the low speed generator option uses the more proven technology but is heavy/bulky and less efficient.
Neither am I a combustor expert! but I have listened in the past to people who are and I remember that it is not straightforward to change fuels without redesigning the combustor, particularly if emissions are a factor. Also combustor life is an issue even with natural gas - perhaps even as low as 10,000 hours.
At 30kW you are below the typical 100kW ratings of Combined Heat and Power units (Turbec, Elliott-Ebara, Bowman Power) but a bit above the automotive developments (energy recovery from exhaust gases, fuel cell energy recovery). However, there may be truck or bus equivalents of around that power - an 8 litre engine at full power may have up to 50kW available for recovery from exhaust gases.
RE: Capstone Turbine
RE: Capstone Turbine
RE: Capstone Turbine
Since the Capstone unit is provided as a single piece, with rectifier and inverter co-located I expect I must find another solution to fit my envelope. Your list of the larger combined providers is helpful, I had not contacted Turbec previously.
Does anyone know of a small on-demand combined heat/power unit for 10-15kW power and 13kW min heat? I am able to accept a larger overall package provided that the fuel-burning unit remains smaller than 0.9m x 0.6m x 0.5m and weighs less than 190kg. A seperate controller/rectifier/inverter is actually desired as these components can then be located out of the weather. IF the controller allows output to synch with utility mains it is even better. Efficiency is greatly desired, if we could keep consumption below 2.0L/hr (diesel) this would be perfect.
Looking forward to your comments.
Thanks, Alex
RE: Capstone Turbine
yours
RE: Capstone Turbine
Unit is always running, at low heat demand when mains are present unit can draw power from mains for to keep rotation to turbine to minimize fuel consupmtion (is at idle state hope very small fuel use <0.5l/hr.)
When mains lost, unit must achieve self-sustaining running and generate power, load to vary from 1-15kW hope fuel is consumed dependent on load. Heat output can be any, have cooling system to keep temperature between setpoints
If heat demand increases (from temperature drop in cooling system) unit to increase fuel consumption to maintain temperature within setpoints...if can generate power to mains synchronously when present is best.
Can stop unit regularly for maintenence and if needed to change fuel source to other type. Best if unit can use both liquid or gaseous fuel, I can accept change in output/consumption from other sources than diesel.
Does this help?
Thanks,
Alex
RE: Capstone Turbine
RE: Capstone Turbine
http://s
(quite an interesting article, it mentions the main players in the microturbine market although it is about 5 years out of date)
- this will equate to a diesel consumption of about 0.1litre/kWhr mechanical output, with an efficiency of 30% and calorific values of 50MJ/kg and 40MJ/kg for natural gas and diesel respectively. So 2 litres/hr should give you up to 20kW elec and 45kW heat (although of course not all that heat energy could be recovered usefully).
If only I could be positive about sourcing a unit! As stated in the above-mentioned article, Capstone are at the bottom end of the microturbine CHP market in terms of kW output. Bowman Power did produce some mobile power units close to your rating for a military application here in the UK I think (hope I don't get in trouble for mentioning that!) but it wasn't in series production. Development times and costs are high, you will have to have high volumes in mind to make it viable.
RE: Capstone Turbine
My volume is too low for special production (under 520/yr) and only for short run ~2-3yrs.
I expect efficiency of larger turbine if only running 1/2 (or less) of rated output will be bad, must require minimum fuel/speed so I am probably out of luck there.
Thanks everyone!
RE: Capstone Turbine
RE: Capstone Turbine
I am confused... You have mentioned "lost mains" and "controller allows output to sync with utility mains"
and "when mains lost".
But you are also saying this is a "small mobile unit"?!?!
Is this stationary or mobile?
RE: Capstone Turbine
When I saw your figures I had visions of retiring with a million or so before the end of the year. I have a client who uses around 2000 galons a day of diesel fuel. I phoned Capstone. I am afraid your figures are somewhat optomistic.
I understand that consumption is about 3 times your estimates.
Good-by to my dreams of easy street.
It is still a great product with a lot of economically sound applications.
yours
RE: Capstone Turbine
RE: Capstone Turbine
Imagine application where mobile unit is positioned distance from anywhere for months, after much construction mains are available (maybe 80% uptime) and connected. Unit sits for more months making only heat (and backup for lost mains) then is relocated another distance away to start again.
waross,
Thanks for checking, I did not get soonest response from Capstone but I contacted via e-mail, maybe they caught me in the spam filter. Capstone is 6l/hr at 30kW electrical (their smallest unit?) Or at only 15kW?
I am starting over on envelope, and maybe having 30kW is not too much but to use 12l/hr would not be possible...does Capstone thottle down in proportion to load?
RE: Capstone Turbine
I really like the Capstone even though I only heard about it on this post. I think there are a lot of co-generation applications that would be very cost effective.
I mean co-generation as I originally understood it, a synergy of power, heat, refrigeration, waste energy use, and similar applications, rather than anything that sells power to the utility company, as the term is often used now.
Through this thread I learned about the adsorbtion refigeration systems that work with the Capstone as well as with other waste heat applications. I have a couple of clients that may be interested.
Back to the Capstone. A diesel will give you about 30% more kilowhatt hours per gallon. You have a lot of heat available from both the cooling system and from the exhaust for heating aplications. The cost is much less. I just checked a recent quotation for an 18.9 KW diesel (1800 RPM). Cost per Kilowatt about 1/2 the turbine. Tax advantages could help the turbine. I looked at a quotation from last November for a 35 KW set (1800 RPM), it was less than 40% of a 30 KW Capstone.
Hope this helps your project.
yours
RE: Capstone Turbine
Check what I believe is a realistic solution.
A Fischer Panda. They come packaged in a high quality sound attenuation suitcase. They are HIGHLY compact. They are designed for extreme shock and angular operation since their biggest use is sailboats. The case has plumbing fittings as the cooling water is sent to a remote sink, be it a hull cooler or a radiator or domestic heating cores. They come in 8kW, 12kW, 15kW, and 20kW (electrical) They are very efficient since their duty is in a limited fuel availability system(sailboats). Since they are always encased for sound they are designed to put all waste heat into the water which maximizes the "waste" heat concentration for your use.
The A/C generator versions use a water cooled sychronous generator making it about half the size it would normally be.
Give'em a look see.
http://www.fischerpanda.com/html/home.html
www.flaminsystems.com
RE: Capstone Turbine
Co-generation is exactly what I saw when I looked to Capstone first time too...power/heat all in one for my application. Unfortunate for me they have 30kW smallest unit.
itsmoked,
I had seen a Fischer before but I thought the turbine would be longer life as fewer wear parts. Also for when only heat needed I think the turbine could run with mains to turn it and only enough fuel to make desired heat output.
I think I will call Fischer to discuss my application.