Stirling engine is a closed-cycle regenerative heat engine, wherein the working fluid is permanently confined within the system. The working fluid is gaseous in nature. Stirling engine works by the cyclic compression and expansion of the gas inside a cylinder, which leads to the generation of heat inside the heat engine. The heat generated is then converted to mechanical work by pushing a piston. There are three types of stirling engines: the alpha type, the beta type, and the gamma type. Lamina flow engine is another type of stirling engine which is s. till in the R&D phase. The alpha type requires high temperature and produces the most power as it has two power pistons. The beta type requires less heat as compared to the alpha type. In the beta type, the power piston and displacer are placed within the same cylinder. Gamma stirling engine requires the least amount of heat. It is also known as the low temperature differential stirling engine.
Micro stirling engine is the smallest, low temperature differential stirling engine. It can run on low temperature and at high speed. Micro stirling engine is difficult to manufacture, but runs successfully when compared to large stirling engines. The amount of working fluid within the engine is much lower as compared to the larger stirling engines. A large stirling engines might be able to overcome only a small amount of friction, while a micro stirling engine stops in-case any friction occurs. Demand for micro stirling engine is expected to rise exponentially in the next few years.
Micro stirling engine is unique, as its theoretical efficiency is nearly equal to the Carnot cycle efficiency. It is sometimes also called external combustion engine, as the heat source is located outside the unit. Micro stirling engine is fuel flexible. It uses natural gas, but may also run on biogas or hydrogen. These gases can be used when they are widely available in the near future. Micro stirling engine represents a transitional technology and potential renewable energy converter. This is expected to drive the micro stirling engine market in the near future. Various applications of micro stirling engine include water pump stations, combined heat and power plants, solar power generation, stirling cyro-coolers, and micro CHP.
Micro stirling engine operates in silence and offers very high efficiency. This is a major advantage of micro stirling engine. Furthermore, it is ecological as this type of engine achieves complete combustion. It offers high reliability due to the technological simplicity. It also requires little maintenance.
In terms of geography, the micro stirling engine market can be segmented into North America, Europe, Asia Pacific, Middle East & Africa, and Latin America. The market for micro stirling engine in North America is currently in the developing stage, followed by that in Europe. The outlook for the micro stirling engine market appears positive in North America, as they can be be used with solar collectors. Similarly, in Europe, the demand for micro stirling engine is rising due to the major emphasis to provide flexibility of system to integrate heat pump systems. Concerns related to the environment, maturity of associated markets such as residential boilers, and rising interest in distributed generation are the major drivers of the the micro stirling engines market.
The key players operating in the Micro stirling engine market are Cleanergy, Genoastirling S.R.L., Ekogen, Preser, Sun Power, OkoFen, etc.