18 Wikipedia - Advanced steam technology May 3, 2014
Wikipedia - Advanced steam technology May 3, 2014
The Wikipedia article, “Advanced steam technology” (also known as Modern Steam) is good, but incomplete. It should be expanded to include the advanced multiple-stage steam engine with steam reheating between stages. The Wiki article notes that “The only steam installations that are in widespread use are the highly efficient thermal power plants used for generating electricity on a large scale.” These installations are all multiple-stage with reheating between stages. The same principles used in generating electricity can also be employed in Modern Steam engine applications (automobile, train, boat, etc.). In 1902, a four-stage steam engine with reheating between stages set the world speed record for boats. The record still stands. (“The Steam Automobile Bulletin,” May-June, 2011, pages 8, 23) In June, 1921, a four-stage steam engine with reheating between stages achieved a thermal efficiency of 31.1 percent. This is very good efficiency even by modern standards. (Marks Mechanical Engineers’ Handbook, Fourth Edition, pages 1202-1203) With modern materials and technology, even better results can be realized.
In April, 1977, the U.S. Department of Energy published a report, “An Assessment of the Technology of Rankine Engines For Automobiles.” On page 53, the report states: “Superior fuel economy will be a firm requirement for any future automobile engine. Based on the insights gained in the ERDA (Energy Research and Development Administration) program, SES (Scientific Energy Systems Corporation) has published design concepts and calculations for future steam engines of greatly improved efficiency. These speculative designs are based upon the use of two-stage reciprocating expanders, with reheating of the steam between expansion stages. Reheat cycles have commonly been employed in stationary power plant practice for the purpose of increasing thermal efficiency. This cycle had been proposed by Abner Doble in 1937-1938 for motor vehicle use. ... The “Mark II” design is conceivable after a major program of expander research and development, including high-level effort in expander lubrication.”
For the preceding quote, the D.O.E. referenced the Society of Automotive Engineers paper “760342, The Application of the Positive Displacement Reciprocating Steam Expander to the Passenger Car, Roger L. Demler, Scientific Energy Systems Corp., February 23-27, 1976.” Some quotations from pages 9-13 of this paper follow: “The Mark II engine is designed to maximize materials utilization in a high-efficiency moderate-cost engine. ... THE MARK II ENGINE - REHEAT CYCLE – An advanced reheat-cycle steam engine ... Table I illustrates that the Mark II engine peak efficiency could be 63% higher ... . Lubrication of the expander would be the major research task required in the development of this engine. A counter-flow expander design provides the most control of the piston ring environment. Steam would be exhausted through an exhaust valve in the head rather than through liner exhaust ports at the bottom of the stroke. This provides maximum separation of steam and oil. The piston rings can now be positioned well below the top of the piston. The ring temperature can then be selected by positioning the rings on the piston to operate in the cooler portion of the liner temperature gradient. ... The steam engine’s superior match to the duty cycle is evident in the relative cruise economies. ... The Mark II reheat steam engine has a better cruise fuel economy than the Stirling with identical peak engine efficiency. ... The Mark II steam engine would continue to have superior fuel economy by virtue of its high peak efficiency. ... Major improvements in fuel economy can be expected ... . Increases in design point expander brake efficiency will be achieved ... .”
It is clear there is much potential in advanced steam technology for the development of multiple-stage reheat engines. There is also significant history and ongoing research into such steam engine technology that should be included in an article discussing Modern Steam.
In the 1960s, the Cozby brothers – John, Lewis, David and Kenneth – began research into modern advanced steam engine technology. In the 1970s, their focus moved to high-efficiency multiple-stage systems with reheating between stages. In the 1980s, they formed Cozby Enterprises, Inc. They received a patent on the “unitary steam engine” and worked under a grant contract with the State of Montana on a project to support the engineering, design and potential of multiple-stage reheating steam engines.
Cozby Enterprises, Inc. of Montana, U.S.A., is continuing to work to realize the potential of multiple-stage counter-flow reheat engines for automobiles. Additional information is available on the website cozincmtusa.com. Special attention is directed to sites 16 and 17.
John A. Cozby
P. O. Box 1104 Anaconda, MT59711 ph: (406) 563-5186 alt: (406) 560-0118 fbcanaconda@msn.com