What is thermal efficiency?
Q: What is thermal efficiency?
A: Thermal efficiency is a dimensionless performance measure of a thermal device such as an internal combustion engine, boiler, or furnace. It is calculated by dividing the output by the input of the device.
Q: What are some examples of thermal devices?
A: Examples of thermal devices include internal combustion engines, boilers, and furnaces.
Q: What is the input to a thermal device?
A: The input to a thermal device is heat or the heat-content of a fuel that is consumed.
Q: What is the desired output from a thermal device?
A: The desired output from a thermal device can be mechanical work, heat, or both.
Q: How can we define thermal efficiency in general terms?
A: Thermal efficiency can be defined generally as Output/Input.
Q: What range does the value for ηth fall between?
A: The value for ηth must be between 0 and 1.0 when expressed as a percentage it must be between 0% and 100%.
Q: Are typical values for ηth usually close to 100%?
A: No, due to inefficiencies such as friction and heat loss typical values for ηth are much less than 100%. For example, gasoline automobile engines typically operate at around 25% while large coal-fueled electrical generating plants peak at about 36%, with combined cycle plants approaching 60%.
