Russ College of Engineering and Technology

Mechanical Engineering Department

Stirling Cycle Machines

by Israel Urieli (latest update: 7/27/2013)

This is a pot-pourree of links, mainly to form background information for the course on Stirling Cycle Machine Analysis. This course was last presented in Spring 2012, however the content is available as a web resource and is regularly updated. A quick search on the web will reveal hundreds of links, and the following annotated set is only to get you started.

Athens, Ohio

For the past 50 years Athens, Ohio has been a hotbed of Stirling cycle machine activity, both engines and coolers, and includes three R&D and manufacturing companies as well as David Gedeon, an internationally recognized consultant in the area of Stirling cycle computer analysis.

Sunpower, Inc. was formed by William Beale around 50 years ago, mainly based on his invention of the free-piston Stirling engine. Sunpower is mainly an R&D company, licensing its technology globally, and also manufactures Stirling cycle croygenic coolers for liquifying oxygen. Update (2013): Sunpower was recently acquired by AMETEK, Inc in Pensylvania, however continues doing Stirling cycle machine development in Athens, Ohio.

Stirling Technology, Inc. is a spinoff of Sunpower, and was formed in order to continue the development of the 5 kW ST-5 Air engine. This engine burns biomass fuel (such as sawdust pellets or rice husks) and can function as a cogeneration unit in rural areas.

Global Cooling, Inc is a spinoff of Sunpower, and was formed mainly in order to develop free-piston Stirling cycle coolers for home refrigerator applications. These systems, apart from being significantly more efficient than regular vapor-compression refrigerators, have the added advantage of being compact, portable units using helium as the working fluid (and not the HFC refrigerants such as R134a, having a Global Warming Potential of 1,300). More recently Global Cooling decided to concentrate their development efforts on systems in which there are virtually no competitive systems - cooling between -40°C and -80°C, and they established a new company name: Stirling Ultracold.

Solar Heat and Power Cogeneration

With the current energy and global warming crises, there is renewed interest in renewable energy systems, such as wind and solar energy, and distributed heat and power cogeneration systems.

Cool Energy, Inc of Boulder, Colorado, is currently in advanced stages of developing a complete solar heat and power cogeneration system for home usage incorporating Stirling engine technology for electricity generation. This unique application includes evacuated tube solar thermal collectors, thermal storage, hot water and space heaters, and a Stirling engine/generator.

Stirling engine discussion e-group

The Stirling Engine Society USA (sesusa) is a group of enthusiasts, professionals and academics dedicated to exchanging knowledge, ask questions, and express ideas on Stirling engines. Their web page is well worth visiting, and includes basic background, history and theory of Stirling engines, as well as a good set of Stirling engine links. Anyone having an interest in Stirling engines can subscribe to the sesusa discussion e-group, and then you can either ask questions or simply lurk in the background and follow the various ongoing discussions.

Various links

An wonderful site by Bob Sier - including links, books, index of manufacturers of models, as well as a source of components, materials, drawings etc. The best historical information on the early pioneers that I know of, including Robert Stirling and a delightful animation of his original machine.

The ubiquitous Wikipedia - Stirling engine website presents an overview and introduction to the Stirling engine which includes some excellent animations giving a clear insight as to the operating principles of these machines.

Andy Ross of Columbus, Ohio has been developing small air engines with extremely innovative Alpha designs, including the classical Ross-Yoke drive and more recently a balanced "Rocker-V" mechanism. Matt Keveney has done an animation showing clearly the principles of operation of the Ross yoke linkage mechanism. Andy Ross has written an article on the model Climax locomotive that he recently built using a small Rocker-V engine. I am delighted to have available a reprint of this article "A Class A Climax Locomotive".

An interesting site from Japan by Koichi Hirata (in English, luckily) - Assembly drawings, pictures and description of some unique model Stirling engines - even one using glass syringes!

Analysis of Stirling Cycle Machines

The ideal Stirling cycle machine is easily analysed using basic thermodynamics, however the analysis of actual Stirling cycle machines is extremely complex and requires sophisticated computer analysis.

On to Stirling Cycle Machine Analysis

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