5141 Part Load Performance

Since electrical loads in buildings and industrial processes vary with time, under certain dispatch control scenarios, MT output may need to be modulated. The details of this are described in Chapter 7. Operation at other than full power is commonplace. Therefore, the designer, economic analyst, and manufacturer need to understand part load performance of MTs. This section summarizes that topic.

The part-load performance of open cycle gas turbines is treated by Stone and Eberhardt (1962). They concluded that all conventional fixed geometry open-cycle engines within the normal range of pressure ratio and TITs have similar percentage rates of increase of specific fuel consumption (SFC, fuel used per kW output) with decreasing load, with the exception of moderately low pressure ratio cycles with a high degree of exhaust recuperation and with the ability to maintain a high TIT at part load. The single-shaft, high speed MT with variable speed operation and power conditioning lends itself, therefore, to improved part-load fuel economy, especially with intrinsically increased recuperator effectiveness at lower part load airflows, provided that an adequate compressor surge margin exists.

Figure 5.5 shows the generic part-load characteristics of a typical recuperated MT operating at either constant speed and variable TIT, or variable speed and constant recuperator inlet temperature. The variable speed mode improves part-load performance but requires a control system able to sense load and optimize speed. Exposure to high cycle fatigue failure is increased. Generally, constant speed operation is preferred for both improved life and frequency regulation, which is of concern since it affects the driven electrical equipment.

Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

Get My Free Ebook


Post a comment