New 1000 kW Gas Combined Heat and Power System Employing Cost Effective Technologies

摘要

Following the enormously devastating earthquake that hit the Tohoku region of north-eastern Japan in March 2011, there have been considerable changes about our attitudes and views on energy systems in Japan. Some of the major changes include raising pertinent questions about the long-term prospects for the configuration of the primary energy sources and how to provide energy in a more sustainable and efficient way. In light of these questions, gas combined heat and power (CHP) systems have attracted attention as one of the solutions in preventing electricity shortages during power outages, and as effective energy-saving systems. However, the CHP share of total national power production is still only 3.5%, so there is further potential to expand the use of these systems. With these circumstances in mind, the GS16R2 engine, a new 1000 kW gas CHP system with a 1000 rpm at 50 Hz capability, was launched on November 1, 2013. The engine was jointly developed by Tokyo Gas Co. Ltd and Mitsubishi Heavy Industries Ltd (MHI). The companies adopted the unique concept of lowering the engine's speed while increasing its output and efficiency. The following techniques have been shown to improve both electrical power output and total efficiency, while also reducing maintenance costs. This has considerably reduced the overall running costs of the system. ? Longer maintenance intervals and lower maintenance costs The intervals between maintenance periods for the new engine have been extended due to the friction wear of components being reduced by lowering the operating speed from 1500 to 1000 rpm. This low-friction technique makes it possible to reduce the engine maintenance frequency and costs by approximately 30%. ? Increases in electrical efficiency and total efficiency The upgraded engine control technologies and the high-efficiency turbocharger help the system achieve an electric power efficiency of 42.3%, which is the highest in the 1000 kW engine range. In addition, the total efficiency is further enhanced to 78.5% by using a two-stage intercooler system that recovers waste heat from the compressed fuel-air mixture. ? Higher power output To compensate for the lower engine speed, which usually reduces the power output, a longer piston stroke is used in order to increase the power generation capability. In addition, a high efficiency turbocharger increases the amount of compressed fuel-air mixture that enters the combustion chambers. ? Ease of installation The overall width of the system package is reduced by 500 mm (from 3000 mm to 2500 mm) to meet more customer requirements under varying installation conditions.