Advanced steam technology

Sentinel-Cammell steam railcar

Advanced steam technology (sometimes known as Modern Steam) reflects an approach to the technical development of the steam engine intended for a wider variety of applications than has recently been the case. Particular attention has been given to the long-term endemic problems that have led to the demise of steam power in a commercial environment; these include excessive pollution, maintenance costs, labour intensive operation, low power/weight ratio, and low overall thermal efficiency. This applies particularly to medium and small-scale installations where steam power has generally now been superseded by the internal combustion engine or by electrical power drawn from an electrical grid. The proposed steam engines may be for stationary, road, rail or marine use.

Improving steam traction

Although most references to "Modern Steam" apply to developments since the 1970s, certain aspects of advanced steam technology can be discerned throughout the 20th century, notably as regards automatic boiler control along with rapid steam raising from cold.

Abner Doble

From 1922 Abner Doble developed an electro-mechanical system that reacted simultaneously to steam temperature and pressure, starting and stopping the feed pumps whilst igniting and cutting out the burner according to boiler pressure.^[1] The contraflow monotube boiler had a working pressure of from 750 psi (5.17 MPa) to 1,200 psi (8.27 MPa) but contained so little water in circulation as to present no risk of explosion. This type of boiler was continuously developed in the USA, Britain and Germany throughout the 1930s and into the 1950s for use in cars, buses, trucks, railcars, shunting locomotives (US; switchers), a speedboat and a small aeroplane.

Sentinel

In the UK, Sentinel Waggon Works developed a vertical water-tube boiler running at 275 psi (1.90 MPa) which was used in road vehicles, shunting locomotives and railcars. Steam could be raised much more quickly than with a conventional locomotive boiler.

Holcroft and Anderson

Trials of the Anderson condensing system on the Southern Railway (Great Britain) took place between 1930 and 1935. Condensing apparatus has not been widely used on steam locomotives, because of the additional complexity and weight, but it offers four potential advantages:

• Improved thermal efficiency
• Reduced water consumption
• Reduced boiler maintenance for limescale removal
• Reduced noise

The Anderson condensing system uses a process known as mechanical vapor recompression. It was devised by a Glasgow marine engineer, Harry Percival Harvey Anderson.^[2] The theory was that, by removing around 600 of the 970 British thermal units present in each pound of steam (1400 of the 2260 kilojoules in each kilogram), it would be possible to return the exhaust steam to the boiler by a pump which would consume only 1-2% of the engine's power output. Between 1925 and 1927 Anderson, and another Glasgow engineer John McCallum, conducted experiments on a stationary steam plant with encouraging results. A company, Steam Heat Conservation (SHC), was formed and a demonstration of Anderson's system was arranged at Surbiton Electricity Generating Station.

SHC was interested in applying the system to a railway locomotive and contacted Richard Maunsell of the Southern Railway. Maunsell requested that a controlled test be carried out at Surbiton and this was done about 1929. Maunsell's technical assistant, Harry Holcroft, was present and a fuel saving of 29% was recorded, compared to conventional atmospheric working. The Southern Railway converted SECR N class locomotive number A816 (later 1816 and 31816) to the Anderson system in 1930. The locomotive underwent trials and initial results were encouraging. After an uphill trial from Eastleigh to Litchfield Summit, Holcroft is reported as saying:

"In the ordinary way this would have created much noise and clouds of steam, but with the condensing set in action it was all absorbed with the ease with which snow would melt in a furnace! The engine was as silent as an electric locomotive and the only faint noises were due to slight pounding of the rods and a small blow at a piston gland. This had to be experienced to be believed; but for the regulator being wide open and the reverser well over, one would have imagined that the second engine (an LSWR T14 class that had been provided as a back-up) was propelling the first".^[3]

The trials continued until 1934 but various problems arose and the project went no further. The locomotive was converted back to standard form in 1935.^[4]

Andre Chapelon

The work of French mechanical engineer Andre Chapelon in applying scientific analysis and a strive for thermal efficiency was an early example of advanced steam technology.^[5][6] Chapelon's protege Livio Dante Porta continued Chapelon's work.^[7]

Livio Dante Porta

Postwar in the late 1940s and 1950s some designers worked on modernising steam locomotives. The Argentinian engineer Livio Dante Porta in the development of Stephensonian railway locomotives incorporating advanced steam technology was a precursor of the 'Modern Steam' movement from 1948.^[8]:3-6 Where possible, Porta much preferred to design new locomotives, but more often in practice he was forced to radically update old ones to incorporate the new technology.

Bulleid and Riddles

In Britain the SR Leader class of c1949 by Oliver Bulleid and the British Rail ‘Standard’ class steam locomotives of the 1950s by Robert Riddles, particularly the BR Standard Class 9F, were used to trial new steam locomotive design features, including the Franco-Crosti boiler. On moving to Ireland, Bulleid also designed CIÉ No. CC1 which had many novel features.

Achieving the ends

The Sir Biscoe Tritton Lecture, given by Roger Waller, of the DLM company ^[9] to the Institute of Mechanical Engineers in 2003^[10] gives an idea of how these problems are being addressed <what problems?>. Waller refers mainly to some rack and pinion mountain railway locomotives that were newly built from 1992-98. They were developed for three companies in Switzerland and Austria, and continued to work on two of these lines as of 2008^[update]. The new steam locomotives burn the same grade of light oil as their diesel counterparts, and all demonstrate the same advantages of ready availability and reduced labour cost; at the same time they have been shown to greatly reduce air and ground pollution. Their economic superiority has meant that they have largely replaced the diesel locomotives and railcars previously operating the line; additionally, steam locomotives are a tourist attraction.

A parallel line of development was the return to steam power of the old Lake Geneva paddle steamer Montreux that had been refitted with a diesel-electric engine in the 1960s.^[11] Economic aims similar to those achieved with the rack locomotives were pursued through automatic control of the light-oil-fired boiler and remote control of the engine from the bridge, enabling the steamship to be operated by a crew of the same size as a motor ship.

Checklist

All this can be summed up as follows on the basis of the DLM company prospectus:^[12]

Modern Steam stands for a new economic and ecologic steam technology, providing the following advantages:

• One-man operation for steam locomotives
• Automatic boiler and remote-controlled steam engine for ships
• Light-oil firing with clean combustion
• Low cost of ownership providing good return on investment
• High thermal efficiency of engine and boiler
• High-level insulation of boiler, steam engine and piping
• Modular concept and exchangeable parts
• Up-to-date bearing technology reducing maintenance and protecting the environment

- To which may be added:

• Ready availability for use
• Can also be used as part of a cogeneration system with a petrol, diesel or gas turbine engine
• Lends itself well to combined heat and power (CHP) operation
• Can exploit geothermal sources of steam

Carbon neutrality

A power unit based on advanced steam technology burning hydrocarbon fuel will, like any heat engine using hydrocarbon fuel combustion, inevitably emit carbon dioxide, a long-lasting greenhouse gas. However, significant reductions, compared to other combustion technologies, of other pollutants such as CO and NO_x are achievable by steam technology, which does not involve explosive combustion,^[13] without the need for add-ons such as filters etc. or special preparation of fuel.

If renewable fuel such as wood or other biofuel is used then the system could be carbon neutral. The use of biofuel remains controversial; however, liquid biofuels are easier to manufacture for steam plant than for diesels as they do not demand the stringent fuel standards required to protect diesel injectors.

It has been proposed ^[14] that, given sufficient solar energy, silicon might be refined for use as a coal replacement for this type of engine.

Advantages of advanced steam technology

In principle, combustion and power delivery of steam plant can be considered as separate stages. While high overall thermal efficiency may be difficult to achieve, largely due to the extra stage of generating a working fluid between combustion and power delivery attributable mainly to leakages and heat losses,^[8]:54-61 the separation of the processes allows specific problems to be addressed at each stage without revising the whole system every time. For instance the boiler or steam generator can be adapted to use any heat source, whether obtained from solid, liquid or gaseous fuel, and can furthermore use waste heat; whatever the choice, it will have no direct effect on the design of the engine unit, as that only ever has to deal with steam.

Early twenty first century

Small-scale stationary plant

This project mainly includes combined electrical generation and heating systems for private homes and small villages burning wood or bamboo chips. This is intended to replace 2-stroke donkey engines and small diesel power plants. Drastic reduction in noise level is one immediate benefit of a steam-powered small plant. Ted Pritchard, of Melbourne, Australia, was intensively developing this type of unit from 2002 until his death in 2007. The company Pritchard Power (now Uniflow Power) ^[15] stated in 2010 that they continue to develop the stationary S5000, and that a prototype had been built and was being tested, and designs were being refined for market ready products.^[16]

Until 2006 a German company called Enginion was actively developing a Steamcell, a micro CHP unit about the size of a PC tower for domestic use. It seems that by 2008 it had merged with Berlin company AMOVIS.^[17][18]

Since 2012, a french company, EXOES, is selling to industrial firms a Rankine Cycle patented engine designed to work with a lot of fuels like concentrated solar power as much as biomass or fossil energies. The system, called "SHAPE" for Sustainable Heat And Power Engine, converts the heat into electricity. The engine developped by this firm is suitable for embedded and stationnary applications and has been yet integrated into a biomass boiler and a CSP system. The company is planning to work with car constructors and railways corporations.^[19]

A similar unit is marketed by Powertherm,^[20] a subsidiary of Spilling (see below)

Small ship auxiliaries and large portable generators

Once again quiet operation is the immediate benefit sought in this field, a potential recognised by Ted Pritchard, but nothing of note has yet appeared.

Small fixed stationary plant

The Spilling company produces a variety of small fixed stationary plant adapted to biomass combustion or power derived from waste heat or pressure recovery.^[21][22]

Automotive uses

During the first 1970s oil crisis, a number of investigations into steam technology were initiated by large automobile corporations although as the crisis died down, impetus was soon lost.

Ted Pritchard's^[23] main field of research from the late 1950s until the 1970s was the building of several efficient steam power units working on the uniflow system adapted to a small truck and two cars. One of the cars was achieving the lowest emissions figures of that time.

IAV, a Berlin-based R&D company that later developed the Steamcell, during the 1990s was working on the single-cylinder ZEE (Zero Emissions Engine), followed by the compact 3-cylinder EZEE (Equal-to-Zero-Emissions-Engine)^[24] designed to fit in he engine compartment of a Škoda Fabia small family saloon. All these engines made heavy use of flameless ceramic heat cells both for the steam generator and at strategic boost points where steam was injected into the cylinder(s).

Rail use

• No. 52 8055,^[25] a rebuild of an existing locomotive (East Germany, 1960).

• The 5AT project,^[26] a proposal for an entirely new locomotive (Britain, 2000s).

• The ACE 3000 project,^[27] proposed by locomotive enthusiast Ross Rowland during the 1970s oil crisis. The locomotive would look like a diesel, and was designed to compete with current diesel locomotives by using coal, much cheaper than oil at the time. The ACE 3000 would feature many new technologies, such as automatic firing and water-level control. The locomotive would be able to be connected to a diesel unit and run in unison with it, so that it would not be necessary to hook up two identical locomotives. The ACE 3000 was one of the most publicised attempts at modern steam, but the project ultimately failed due to lack of funds.

Novel versus conventional layout

Both 52 8055 and the proposed 5AT are of conventional layout, with the cab at the back, while the ACE 3000 had the cab located at the front. Other approaches are possible, especially with liquid fuel firing. For example:

• Cab forward type. This is a well-tried design with the potential for a large power output and it would give the driver a good view ahead. Being single-ended it would have to be turned on a turntable, or a triangular junction. Example: Southern Pacific 4294.

• Garratt type. Another well-tried design with large power potential. Example: South Australian Railways 400 class. A future design could include shorter water tanks, and a cab at each end, to give the driver a good view in either direction.

Sentinel-Cammell locomotive

• A design mounted on power bogies with compact water-tube boiler similar to Sentinel designs of the 1930s. Example: Sentinel-Cammell locomotive (right).

Fireless locomotives

Another proposal for advanced steam technology is to revive the fireless locomotive, which runs on stored steam independently pre-generated. An example is the Solar Steam Train project ^[28] in Sacramento, California.

See also

• List of steam technology patents
• Steam car
• Steam locomotives of the 21st century
• Steam motor

References