Stirling gen-set vs steam turbine gen-set

Yes it would be interesting to revive the sterling engine but so far and on the inter-net all I can find are makers of gadgets.

Can anybody help me find a real maker of engines for sale for commercial industrial use ? Not just souvenir for desk tops. Thanks

https://cr4.globalspec.com/blogentry/1783/Future-Energy-Sources-1-10-1-Stirling-Engines

Try United Stirling at Malmo sweden or Phillips at eindoven or the Australian submarine corporation (now tenix i think)

There are lots of sites but you are correct very few commercially available engines. Take a look at www.stmpower.com and www.whispergen.com - both quite different but both commercially available appplications of Stirling engines. In answer to your question about efficiency - it depends, but in simple terms a Stirling engine can be about 33% efficient while a steam turbine will only be at best 22% efficient.

Thanks Mr A.Robertson, this is welcome contribution.( There is no doubt about this CR4 Engineering site, it has some serious people contributing . It also makes a lot of sense as a forum even though there a few weirdoos who pop up from time to time. Regards.

The answer to your question depends much on what you are actually after. Kinda like asking which is faster, a 30000# E.W. dump truck or some exotic sports car. Well it depends if you are hauling one person, or 40 yards of gravel. Sorry to complicate things ;~} And that considering the same fuel part is sort of a catch too. Depending on location and power of genset using a different fuel may be more efficient when it comes to total cost per kW-Hr over expected life of genset. Or maybe you only cared about the thermodynamic efficiency and let someone else worry about economics..?

Well in thermodynamic theory, the max efficiency of either of the two engines is dependant on the heat source and sink. As the Carnot cycle demonstrates, the max efficiency of a heat engine is equal to (1 – Temp of heat sink) / heat source. From there things just keep going down hill as other losses are incurred. From what little I have seen, for small applications (oh say <~100 horse power?) the Sterlings should be more economically efficient. I say 'economically' efficient because the initial startup capital ($$$) increases rapidly as you increase efficiency; perhaps exponentially as you approach the Carnot efficiency asymptote. For larger systems steam has been in use and therefore there was return on invested engineering to improve efficiency through the years, so Steam will be ahead of Sterlings in efficiency practice.

As you probably already know the Sterling cycle is by no means new technology. However, the tricks that are used to boost its efficiency cost effectively are continuously evolving. New materials and processes allow higher mean effective pressures while running lighter gasses. Hydrogen and Helium are over an order of magnitude better working fluids for Sterlings than is air.

Which is more efficient is highly dependant on your systems and desires. If you want a huge expensive play toy/engineering experiment a Sterling may be the most efficient (thermodynamically speaking.)

Dear Juba-Jabba,

Thank you for your informative answer. I have worked previously in a smelter where the heat (not the gases-that is another story and application) was recovered from the rotary kiln dryers used to dry the crushed ore before smelting took place. Some heat from the electric smelters was also recovered and piped to a fuel fired power plant with steam turbines. This has worked extremely well for the last thirty years.

What has prompted my recent interest in the Stirling engine is that (as afar as I know) there are countless applications where such waste - heat recovery could be applied , but are NOT . For instance in coal fire burning power plants ( Particularly in: China.In that country's north , there are countless -and very polluting coal fired- steam generation simply for : air conditionning in winter.) Whilst with modern steel making Companys such as the European do have , ie Italian and Germans, I have yet to see any apparent applications and or market penetration of sterling type heat recovery application in any of their recent installations in : China. This Country is and will remain for a long time to come the one that has the largest population of coal fired installation and probably the largest source of harmfull emissions !

So it seems that the manufacturers have yet to single out the huge market potential which already exists simply:in heat recovery alone . Yet others such as the: Japanese, do have extremely good smelter gas turbines based on the recovery of gas in the smelters . Particulary of iron to steel processing. Whilst, elesewhere the focus appears to be on the solar potential. Obviously this is good but is very costly and forseeably , will remain, like wind power , as intermittent energy source .Good but not fully reliable

In sum it is not an esoteric appreciation of steam against pure heat recovery . No my question is : who is doing something on just the recovery of wasted heat ? Is there not a way of finding the funding for the: imaginative manufacturers of those simple first steps .Yes , those who may create and market a : Model T Ford range of heat recovery engines-gensets combinations that are designed to supply power locally into the grids of this world .

Should we , continue just playing around with: carbon credits ? Will that work ? or will it be another financial bubble : a la Enron ?

Your comments are very insightfull. Indeed there IS someone working on the application of Stirling technology to the very issue you refer. The problem right now is that Stirling engine designs have been targetted at mobile applications and all require a high heat delta. What is needed for the application you have identified is a low heat delta engine designed specifically for the power industry. For now at least the off the shelf answer is secondary heat recovery and imaginative use of low grade heat for heating purposes.

Again, you have very good point and well presented. The fatal problem to your whole concept can be completely blamed on one factor. That factor is that humans are involved. We are some greedy, ignorant fools as a whole. The reason we are not making the most out of those byproduct heat sources have very little to do with a lack of technology. It has much to do with investing capitol and paying back in x number of years and then making profit for many more. If it doesn't make profit in a defined time, nobody wants to take the risk, although the risk is quite low, but unfortunately so would be the return.

Where is the missing link? I would say it's that there is very little done to incorporate the cost of using up our Earth when an economical study is done for a proposed project. I believe that it is very difficult for economists to put a value on Earth and its resources. I personally disagree with the concept of putting a monetary value on natural resources; that value is important only to those who make the rules about fining, compensating, taxing, etc the people/companies that consume (including pollute) the resources.

Furthermore, why would people of a advancing/growing economy want to put a price on natural resources and incorporate it into cost/benefit analysis? I firmly believe that the rate at which a society consumes natural resources has a strong, direct relationship to the rate of that society's economic growth, or lack there of.

Recap:

The use of natural resources is not part of economic analysis, and those in favor of economic growth want it to remain that way as using natural resources is sort of a freebie. So when a project or concept comes along saying it will reduce waste of natural resources but doesn't offer any significant return on investment it will be ignored or put on back burner at best. UNLESS, it is required by law or an influential group actually successfully boycotts related products...

As for me an mine, I'm going to continue to work on developing a way for me to build my own Sterling to incorporate into wood fired heating/(cooling) system. Return on investment? Probably next to nothing; cheaper to buy LP. Enjoyment from actually getting to design and build and tweek something without dealing with all the PITA games that are associated with business work? Priceless.

Torque seems to be an issue also.

Dear Juba-Jaba,

Probably we are of the same "vintage". Off air I would be interested to exchange views and monitor your progress on your project.

My belief is that if something or a project is well conceived and furthermore well built it is never FRUITLESS. So apart from your sense of satisfaction the results will be there.

Regards.