The energy saved is measured in terms of what is utilized to move or operate the machine. For example, for a combustion engine, the reduction in fuel consumption would be measured. For an electric motor and/or gearbox, the reduction of electric energy (voltage, current and power factor) would be measured.
Article originally published on Noria.com.
Energy efficiency must be measured in terms of the reduction of energy consumption. More specifically, it is related to how much energy the machine consumes in order to operate. This principle applies to machines that convert one type of energy like chemical or electric to a mechanical one, such as electric motors and combustion engines.
It is also applicable to machines that transmit mechanical energy, like gearboxes. In some cases, it may be evaluated in a powertrain such as a combination of a combustion engine and a transmission.
(read the entire article, "Determining an Oil's Energy Efficiency," at Noria.com...)
