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High efficiency is particularly relevant in systems that can operate from batteries. Inefficiency may require weighing the cost either of the wasted energy, or of the required power supply, against the cost of attaining greater efficiency. Efficiency can usually be improved by choosing different components or by redesigning the system.
Efficiency of power plants, world total, 2008. Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation), or heat.
To express the efficiency of a generator or power plant as a percentage, invert the value if dimensionless notation or same unit are used. For example: A heat rate value of 5 gives an efficiency factor of 20%. A heat rate value of 2 kWh/kWh gives an efficiency factor of 50%. A heat rate value of 4 MJ/MJ gives an efficiency factor of 25%.
Although it is named "power usage effectiveness", it actually measures the energy use of the data centre. [10] The PUE metric has several important benefits. First, the calculation can be repeated over time, allowing a company to view their efficiency changes historically, or during time-limited events like seasonal changes.
The red crosses denote the most power efficient computer, while the blue ones denote the computer ranked#500. FLOPS per watt is a common measure. Like the FLOPS (Floating Point Operations Per Second) metric it is based on, the metric is usually applied to scientific computing and simulations involving many floating point calculations.
For a given power supply, efficiency varies depending on how much power is being delivered. Supplies are typically most efficient at between half and three-quarters load, much less efficient at low load, and somewhat less efficient at maximum load. Older ATX power supplies were typically 60% to 75% efficient. To qualify for 80 Plus, a power ...
It differs from most power efficiency descriptions calculated (in percent) as: = / PAE will be very similar to efficiency when the gain of the amplifier is sufficiently high. But if the amplifier gain is relatively low the amount of power that is needed to drive the input of the amplifier should be considered in a metric that measures the ...
Electrical efficiency, useful power output per electrical power consumed; Mechanical efficiency, a ratio of the measured performance to the performance of an ideal machine; Thermal efficiency, the extent to which the energy added by heat is converted to net work output or vice versa; Luminous efficiency, a measure of how well a light source ...