GAS-L: Small OCR Devices

[Peter Singfield <snkm@btl.net>]

At 04:38 PM 1/7/2002 -0000, you wrote:
>Peter,
>
>Do you mean  Ormat ORC devices rated at 250kW electrical output? For about
>1.2Mw heat input?
>What temperature the waste heat streams?
>Regards
>Gavin

Hi Gavin;

OK -- starting 2002 with a bang then ---

Zoli Bihari <ZBihari@ormat.com> is on this list and specifically the man at Ormat involved with Biomass projects. I'll let him verify those claims.

But yes -- 250 kwh Electrical.

OK -- now for my "suppositions" --

They have no real "adjustment" for optimal heat recovery -- such as an economizer -- etc. Figure they could surpass 20% easily if they took into account the differences between fixed temperature geothermal heat sources and a furnace/boiler set up.

Just takes a little "plumbing".

Further -- they are presently limited to 250 kwh as the smallest size as that is the smallest turbine they can find that still gives any amount of efficient operation.

For the 1 to 50 kwe range -- it will require a reciprocating piston OCR device to get high efficiencies.

But the potential is certainly there -- even if the interest is not.

Just look at any refrigeration system compressors --- all can be adapted quite well. And they come to 60 kwe sizes no problem. built specifically for hermetically sealed operation using a refrigerant working fluid. Just visualize a generator where the electric motor windings are.

I am hoping that one day Ormat will find it of value to explore this direction of research. As -- in my opinion -- it is a minimal research project and sure to work.

I believe at present they are using turbo expanders as the OCR device. But they will never tell!!

If you wish to "see" what I am talking about --

Atlas Copco has some graphic examples at:

http://www.atlascopco-act.com/turboexpand03.htm

I believe they make their:

"ETG generator-loaded expanders"

As small as 25 kwe --

No big deal to roll one's own if Ormat keeps on avoiding this area of endeavor.

What say Zoli???

For sure -- such systems are super reliable! And zero pressure fire tube boilers live forever! (Thermal Oil heat transfer)

And Zoli -- you "stick" the economizer circuit into the feed return from the condensers and grab another 5% "over-all"  plant efficiency. I very economic proposition for the increase realized.

I know -- up to this point Ormat has only been involved with fixed temperature thermal sources -- such a geothermal and solar -- as in ponds and collectors. But hey -- get with the thermodynamic times.

OCR systems have a super potential in the biomass energy extraction arena. But the great minds running this show are blind to it -- and Ormat is just beginning to make the transition. Further -- they are doing it "their-way" -- and not looking at the broader implications.

The ancient saying comes to mind:

"The Blind leading the blind"

By the way -- though the Ormat is truly a fraction of the example posted -- it is still expensive!

More so than a standard boiler/steam turbine set-up running at high enough temps/pressures to get 25% of better.

However -- if I had their facilities available to "proto-type" a system that would change real quick.


Peter Singfield / Belize
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