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MHI and Tokyo Gas Develop New 1,000kW Gas Engine Cogeneration System
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Tokyo, October 28, 2013 - Mitsubishi Heavy Industries, Ltd. (MHI) and Tokyo Gas Co., Ltd. have jointly developed a new 1,000kW gas engine cogeneration system. Both companies are scheduled to begin sales of the system on November 1, 2013.
Through these efforts for reducing maintenance cost and improving both generating and overall efficiency, the system running cost is considerably reduced. As a result, recovery of initial investment can be recovered approximately three years sooner than the conventional system. Moreover, the width of the enclosure has been reduced by 500 millimeters (mm) compared to the conventional system to serve more customers with various installation conditions.
In recent years, business continuity plans (BCP) and electric power conservation efforts have helped growing customer interest in energy-saving and environmentally friendly gas engine cogeneration systems. In response, MHI and Tokyo Gas have utilized their extensive experience in gas engine cogeneration development and adopted the unique concept of lowering engine speed while increasing output and efficiency to introduce this highly efficient new system to the market.
Working together, MHI and Tokyo Gas will continue to promote cogeneration systems for large-scale applications including urban redevelopment and industrial applications at mid-size factories to expand the business.
*Among gas cogeneration systems with an output up to 1,000kW sold by Japanese manufacturers as of October 1, 2013. (Source: Tokyo Gas Co., Ltd. market research; comparison based on lower heating values)
External view of the new 1,000kW gas engine cogeneration system
Configuration diagram of the new 1,000kW gas engine cogeneration system
Main features
1) Lower maintenance costs by lowered engine speed
Engine speed has been reduced from 1,500 rpm to 1,000 rpm, resulting in reduced wear rate of components and extending the replacement interval for spark plugs and other consumables. Consequently, compared to the conventional system, the minimum oil change interval and other basic maintenance work have been extended to 1.5 times, and the minimum interval for top overhaul has been extended to 1.9 times, reducing overall maintenance costs by approximately 30%.
2) Higher output by lowered engine speed
Although lowering engine speed normally means lowered output, this new system is able to generate higher output as the engine's piston stroke is approximately 20% extended from the conventional system. In addition, the use of high efficiency turbocharger has increased the amount of compressed fuel-air mixture supplied into cylinders, which results in raising the mean effective pressure by 30% from than the conventional system. This enables the new system to deliver higher output (1,000kW, up from 930kW) with lower rated speed.
[New long-stroke piston (conceptual drawing, inside engine cylinder)]
3) Increased generating efficiency and overall efficiency
Improved engine control systems aids achieving generating efficiency of 42.3%, the highest level in the 1,000kW class. In addition, thermal efficiency has been improved by upgrading the one-stage intercooler used on the conventional system to a two-stage intercooler system to achieve overall efficiency of 78.5%.
[Two-stage intercooler (conceptual diagram)]
4) Smaller dimension
The overall width of the enclosure has been reduced by 15% (from 3,000mm to 2,500mm) to suit indoor installation such as hospitals and commercial facilities. Although high-output, high-efficiency systems generally require increased ventilation and capacity for auxiliary equipment, optimal arrangement of components within the new system ensures that space requirements are no greater than that of the conventional system.
| Item | Unit | New System | Conventional System |
|---|---|---|---|
| Engine model | GS16R2 | GS16R | |
| Dimensions of enclosure (width x height x depth) | mm | 2,500 x 4,600 x 7,500 | 3,000 x 4,400 x 6,300 |
| Generating output | kW | 1,000 | 930 |
| Rated engine speed | rpm | 1,000 | 1,500 |
| Generating efficiency | % | 42.3 | 40.0 |
| Steam recovery efficiency | % | 17.3 | 14.8 |
| Hot water recovery efficiency | % | 18.9 | 18.3 |
| Overall efficiency | % | 78.5 | 73.2 |
Efficiency values assume the use of city gas 13A with a lower heating value (LHV) of 40.63MJ/Nm3 and tolerance of +5%.
About MHI Group
Mitsubishi Heavy Industries (MHI) Group is one of the world’s leading industrial groups, spanning energy, smart infrastructure, industrial machinery, aerospace and defense. MHI Group combines cutting-edge technology with deep experience to deliver innovative, integrated solutions that help to realize a carbon neutral world, improve the quality of life and ensure a safer world. For more information, please visit www.mhi.com or follow our insights and stories on spectra.mhi.com.