The latest in Stirling engine research at Frauscher Thermal Motors GMBH

THE LATEST IN STIRLING ENGINE RESEARCH
Dear Sir/Madam,
Next year we will celebrate the bicentenary of Pastor Robert Stirling's ingenious invention. What would the Reverend Stirling think if he was able to get a glimpse today of the immense and controversial consequences that his innovative creation has had? He would probably sit back with a chuckle and look with interest at what his invention has achieved. Countless people, institutions and companies have attempted to find a broad-based commercial use for his idea, before at best throwing in the towel having gained more knowledge or, in the worst case, causing economic damage.
He would no doubt give the thumbs up to the few individuals who remained undaunted and developed his machines until they were ready for serial production and market launch, and would give them his priestly blessing for a successful future. He would definitely smile at the sheer desperation shown by many a mortal at those details of his design that also cost him a lot of sweat in his day. Free from the constraints of time, space and the pressure to succeed, he could calmly watch human's endeavours to use his brainchild for general advancement and the common good.


BACK TO REALITY
The longer we work on the research and development of Stirling engines, the more we realise the following:
In terms of simplicity, efficiency potential and operating performance, the Stirling engine is the most ingenious thermodynamic machine for stationary use in a power range below that in which it makes sense to use turbo engines.
Admittedly, such realisations are not much use if commercial applications fail because they are not economically viable. It is becoming increasingly apparent in this regard that Stirling engines will initially have their place precisely where the use of internal combustion engines ends: the efficient conversion into electricity of hazardous, lean and waste gases and, almost as an additional benefit, the environmentally friendly disposal of these.
As they have a double use, they become economically viable: there are a wide range of gases containing energy that are generated in various processes and must be disposed of as waste products in accordance with the regulations, for example through gas flaring.
Typical examples of such gases include:
- Fractional gases of crude oil
- Landfill gases
- Furnace gases
- Refinery gases
- Mine gas
We should point out here that fractional gases are actually released untreated into the atmosphere in sparsely populated regions, particularly in the oil industry, which, due to their methane content, causes unimaginable damage to the earth's atmosphere. The same applies to landfill gases and mine gases, which are not always collected and disposed of in accordance with the regulations. (See "World Bank/GGFR study").
There are also various gases that, due to their accompanying substances, cannot be used in internal combustion engines without additional costs. Examples of these include wood gases and pyrolysis gases. The conversion of biogases and gases from purification plants into electricity is another exciting challenge. Along with efficiency, the ease of maintenance and service life of the machines are of particular importance here in order to ensure cost-effective operation.
This market is calling for outputs of 30 to 50 kWel per unit. Another challenge lies in developing suitable burners or combustion chambers for these gases and tailoring them to the requirements of the Stirling engine. Preheating the combustion air is an important prerequisite for achieving a satisfactory level of efficiency.


EXPERIENCES WITH THE A600-V3 MACHINE
Since our last newsletter, our Stirling module A600 (5 kWel) has been in operation for another 500 hours. During this time, we have made a number of improvements. This is, of course, only the beginning of the long-term test phase. We are currently making another prototype, which will soon be available for testing.
Tests are being conducted in combination with a biomass furnace as part of a sponsored research project. Investigations are focusing on the durability of the heat exchangers and control of dust deposits.
This year we will begin producing an 11 kWel Stirling module, for which we have already completed most of the calculations and designs. For this module we plan to develop high-performance burners for natural gas, which will then gradually be adapted to lean gases. The concept of the 11 kW machine will also form the basis for the development of more powerful units.


NEW CNC-CONTROLLED MACHINES ENSURE HIGHLY DYNAMIC PROTOTYPE CONSTRUCTION
Our recent investment in a numerically controlled lathe and milling machine will allow us not only to produce new components for the engines quickly, but also to implement changes required as part of improvements within a few hours.
With our high-temperature vacuum furnace for production of heat-proof solder connections for heat exchangers and other parts, we will in future be able to drive forward new and further developments in Stirling technology at a much faster pace.


SUMMARY
During our 14-year research and development phase, we have overcome a series of challenges. In particular, these related to the production processes for heat exchangers, solving the tribology requirements for piston guides, piston rings (dry run) and in engines and controlling static and dynamic seals in conjunction with monatomic gases. Today we are more confident than ever that we will be able to develop this fascinating technology for commercial applications. With my motivated colleagues, I am looking forward to the future. We will be happy to keep you informed of our company's news.

Kind Regards

Sepp Frauscher
Managing Director

Frauscher Thermal Motors GmbH
Gewerbestraße 1 | 4774 St. Marienkirchen | AUSTRIA
T: +43 7711 31820-0 | F: +43 7711 31820-8500
office@frauscher-motors.com | www.frauscher-motors.com
Firmenbuchgericht: Ried im Innkreis | FN: 320883m| UID: ATU 64591999

PS: As we are not yet active on the market, there is unfortunately no sales department as yet to provide advice and customer support. We are focusing our efforts on research and development instead, so that we can offer you products that are suitable for the market in the foreseeable future. We would nevertheless welcome your feedback. Please feel free to e-mail us at martina.billinger@frauschermotors.com. Please understand that it may take some time to answer queries. Many thanks!