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MODERN LINES OF DEVELOPMENT OF STIRLING MACHINES IN THE WORLD

 

1. World tendencies of development of Stirling engines

Works on creation of the competitive Stirling engine, distinguished by cleanliness of emissions, low noise level in view of absence of explosive combustion, absence of systems of local distribution of gas and ignitions and high fuel profitability are carrying out in many countries.
It is necessary to note, that a number of foreign firms starts manufacture of engines which characteristics already now surpass ICE and gas turbine installations in a power range from 1 up to 100 kW. The efficient parameters of the best serial and pre-production models of Stirling engines achieved now even at moderate temperatures of heating (600..700?Ñ) are represented by rather impressive figures - more than 35 %.

However, as a whole, the basic characteristics of power installations offered today in the market on the basis of Stirling engines depending of the manufacturer, changes over a wide range:
- Specific cost from 1300 $ up to 8000 $ for 1kW of the established capacity;
- Service life from 2000 till 80000 hours;
- Efficiency   from 10 % up to 38 %.

The analysis of the information from various technical sources and the data of passports of manufacturers of power installations on the basis of Stirling engines show, that now practically all manufactured Stirling engines are the modernized copies of Stirling engines, created by the Dutch company " Philips " in the middle of the last century or engines of other companies developed under its licenses. These development intended, basically, for automotive industry and  for the companies developing power installations for military needs, such as, “General Motors Co”, “Ford Motor Co”, "MAN-MBW", “United Stirling”, etc. where cost of engines is sufficient low in comparison with cost of system as a whole ( automobile, boats,  submarine, objects of space purpose, etc.). Expensive materials (for example, cobalt, zinc, copper, nickel, etc.) and complex technological execution of original constructive elements were applied at creation of Stirling engines for transport, in view of a plenty of cycles "start-up - stop" and frequently varying capacity, rigid requirements on weight and the sizes. Such approach allowed to achieve required parameters, but considerably raised the cost price of manufacture of products. In particular, it high enough cost of separate existing Stirling engines speaks.

However, full copying of transport types of Stirling engines for stationary power installations cannot be justified. The most significant parameter is the cost connected to complexity of manufacturing and service at their batch production and operation. Mass and dimensional characteristics for stationary installations are not determining.

Now the most perspective direction for application of Stirling engines is creation of co-generation installations for simultaneous manufacture of the electric power and heat which classified as stationary power systems. In this connection, works on creation of Stirling engines have started practically in all large power companies of the world. The programs on Stirling engine  have  been declared by  such firms-leaders in the world on manufacture of power installations, as "TODEM", “ Cummins Power Generation ”, “ Toshiba Corp. ”, “ Mitsubishi Electric Corp. ”, "ÌÑÑ", "Hoval", "Volvo", "SAAB", etc.

Some  new powerful associations have appeared for the last 2-3 years  , for example, the European Swiss-German concern, including the companies «Stirling Systems AG» (Switzerland) and «Stirling Systems GmbH»  (Germany)  and transnational  company, which structure includes some American, Japanese, Italian and German firms (“ Merloni Termosanitari (MTS Group) ”, “Bosch Group ”, "Rinnai", "Infinia").
Occurrence of so large companies uniting significant financial and industrial capacities, speaks a high level of requirements to efficiency of power systems, their ecological cleanliness, increase of requirements on use of renewed and pure local power resources. Certainly, already in the near future it will result rigid competitive struggle in the market of Stirling engines and independent power installations as a whole.   

Economic profitability of anyone power installation is defined basically by expenses for its manufacturing and operational charges. Correct estimation of cost of Stirling engine is inconvenient enough (for the present there is no serial domestic production), but its forecast allows to speak about profitability of manufacture of Stirling engine as a whole. Cost of created production is defined first of all by the following expenses: development of a design, the capital equipment, industrial expenses, materials, operation and maintenance service. Many of these components depend on mass character of manufacture. Experience of small-scale manufacture of Stirling engines available now shows that at mass production from 1000 engines (low power), cost of one engine can decrease in 30 times in comparison with its cost at individual manufacturing.

It is obvious, that now successfully enter on the market of power installations, it is necessary to have the following technical and economic parameters of pre-production models of Stirling engines for their batch production.

.
The basic technical and economic parameters for perspective Stirling engines

Capacity, kW

Cost of 1 kW/h of established capacity,  ths US dollars / kW

Service life, hours

Efficiency, %

Îò 1äî 50

0,8-1,6

More than 30 000

30-40

 

2. World tendencies of development of Stirling cryogenic machines

The special place in cryogenic techniques is occupied by Stirling cryogenic machines (SCM). Now it is the most effective equipment for reception of a deep cold of small and average cold production.  For the first time Stirling cryogenic machines    have been developed by Dutch company "Philips" in the middle of the last century. The developed types of cryogenic gas machines of the given company covered a wide range from tiny machines with cold production in shares of watt up to the big industrial units with cold production in various kW.

Micro-cryogenic devices such as "Split - Stirling" were received the widest circulation. Now they occupy more than 90 % of all market of micro-cryogenics. Now micro-cryogenic systems with SCM are manufactured by many companies all over the world, among them «Stirling Cryogenic Engineering GmbH», «Global Cooling, US», « Honeywell International Inc»,  «JANIS RESEARCH COMPANY, INC.», «Thales Cryogenics BV», «Corporate Communications Raytheon Company», «RICOR Cryogenic and Vacuum Systems», etc.

SCM with a big cold production have found the application in air separating installations for manufacture of liquid nitrogen and oxygen. Machines have high efficiency, small weight- and-dimension characteristics and are simple in operation. These installations have received wide recognition in 60-70 of the last century  and their various updating  began to be made in Europe, Russia and the USA  by the  companies “Stirling Cryogenics and Refrigeration BV”, "Werkspoor", “ North American Philips “, "Arsenal",  "Heliymash", etc.

In connection with change of a policy of company "Philips" and refusal of not profile directions affiliated firms « North American Philips » and "Werkspoor" have been closed in 70-80 of the last century, and the enterprises "Arsenal" and "Heliymash" have ceased to let out given production and have practically lost scientific and technical potential necessary for it because of "perestroika" and the general recession in economy of Russia in 90th years . Now the unique manufacturer of Stirling cryogenic machines is the company "Stirling Cryogenics and Refrigeration BV". With the account of constantly increasing demand on SCM of the given class and absence of competitors, the company « Stirling Cryogenics and Refrigeration BV » having monopolized this area of techniques, raises a sale price of production and thus receives significant super profits. 

3. World tendencies of development of Stirling refrigerating machines of the moderate cold

According to many experts, manufacture and use of Stirling refrigerating machines of the moderate cold is one of the most perspective directions of development of refrigerating techniques in XXI century that is caused by ecological cleanliness of used working bodies and high efficiency of Stirling cycle.

Stirling refrigerating machines are non-polluting machines. Helium is used as a working body and also nitrogen, hydrogen and air can be applied, i.e. substances completely neutral to an environment that allows to meet the most rigid requirements of the Montreal and Kyoto Protocols.

Wide introduction of Stirling refrigerating machines of the moderate cold will allow at the complex approach “efficiency + ecological cleanliness” appreciably to solve a problem of use of non-polluting technologies in view of performance of requirements of the Montreal Protocol.
The idea of use of Stirling cycle to creation of refrigerating machines of a moderate cold is not new.  Pre-production models of Stirling refrigerating machines which subsequently have received a wide circulation have been made by Gershwin in 1834. Such machines were successfully maintained in the food-processing industry, many trade vessels of England had been equipped with them for freezing fish. Stirling refrigerating machines were used in Scotland at factories on manufacture of paraffin mastics since 1876. However because of their imperfection, they have been completely superseded by compressor refrigerating machines at the beginning of XX century.

Revival of interest to use of Stirling machines at a level of a moderate cold is connected to rough growth of scientific and technical knowledge and the significant successes achieved recently in the field of creation of Stirling engines and cryogenic machines. All this has resulted in an intensification of scientific researches on creation of an alternative refrigerating machinery of a moderate cold on the basis of Stirling cycle.

Now perspectives of use of Stirling machines in the field of a moderate cold become obvious. The analysis of the modern foreign scientific and technical information allows to assert, that last 10 years intensive research and developmental works on preparation for a batch production of Stirling refrigerating machines have begun in industrially advanced countries. Beside the countries - leaders in the field of designing and creation of Stirling machines, what  is USA , the Great Britain, Japan, Germany, Sweden and Netherlands, recently  intensive researches in the given area of techniques have begun  in China, the Republic of South Africa, Australia, Israel, Canada, India and a number of other countries.

Such known firms, as "Toshiba",  LG Electronic Inc», "Carrier", "Sanden", «Zexel Corporation», «SOLO STIRLING GmbH», «Stirling Technology Company», «Mitchell Stirling Systems Inc», «AEG AG», «Kubota Corporation», «Stirling Thermal Motors», « Stirling Power Systems » « Sunpower Inc.», «General Electric», «Western Research Centre» and many others now are engaged in manufacture and research of Stirling refrigerating machines  of the moderate cold .

Samples of Stirling refrigerating machines for domestic refrigerators, auto-refrigerator techniques, industrial systems of cold supply, refrigerating show-windows, chests, etc. are already developed and are going to a batch production. The analysis of the basic characteristics of existing refrigerating machines and pre-production models of Stirling refrigerating machines shows that already today Stirling refrigerating machines can successfully compete in a range of the cold production from 0,1 up to 50 kW at temperature of cooling up to - 20?Ñ, and at temperature of cooling from-40 up to-80?Ñ have not equal on efficiency and ecology.

 

 

 

 
 
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