Study on the Parameters Influencing Efficiency of Micro-Gas Turbines: A Review

The art and science of gas turbine has traditionally seen a gradual and continuous change over the past few decades. Gas turbines are classified into impulse and reaction types and further into turbojet, turbofan, turboprop, after burning turbojet and micro gas turbine. These turbines find applications in airplanes, large scale industries etc. but these are less suitable for the small scale power generation units due to several factors. Micro gas turbines are set to play a significant role particularly in small-scale power generation using combined heat and power generation among all these types of turbines as the future of power generation lies in decentralised and distributed power generation systems. In the light of making use of the high temperature exhaust of a gas turbine, combined heat and power generation systems are being used to increase the power output and overall efficiency. Micro gas turbines are essentially single-stage, single-shaft and low pressure gas turbines whose capacity ranges from 30–150 KW. In comparison to the conventional turbines, micro gas turbines are compact and have low lubricating oil consumption leading to a simpler lube and sump oil system and because they have fewer rotating parts, this leads to lesser balancing problems. The analysis of micro gas turbines has shown that they are capable of meeting current emission standards of NOx and other pollutants. Even though the installation costs of micro gas turbines are high due to the complexity in adjusting to electrical grid frequency, still these distributed energy systems may prove to be more attractive in a competitive market to those seeking increased reliability as they empower these entities with the capacity of self-generation. The following text reviews the developments in the micro gas turbines with a special focus on the efficiency of its components such as the recuperator, the combustion chamber design and also explores the future prospects of the technology in terms of viability of its application in the automobile sector.