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Hydropower (from Ancient Greek ὑδρο-, "water"), also known as water power or water energy, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of a water source to produce power. [1] Hydropower is a method of sustainable energy ...
The human body always works to remain in homeostasis. One form of homeostasis is thermoregulation. Body temperature varies in every individual, but the average internal temperature is 37.0 °C (98.6 °F). [1] Sufficient stress from extreme external temperature may cause injury or death if it exceeds the ability of the body to thermoregulate.
Other types of power stations are subject to different efficiency limitations. Most hydropower stations in the United States are about 90 percent efficient in converting the energy of falling water into electricity [8] while the efficiency of a wind turbine is limited by Betz's law, to about 59.3%, and actual wind turbines show lower efficiency.
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. The resulting value, η (eta), ranges between 0 and 1. [1] [2] [3]
Water covers an estimated 71 percent of the Earth's surface. In conjunction with normal weather patterns such as evaporation and precipitation, water is a natural renewable resource that is in abundance on Earth. Murray 2 Power Station. Hydroelectric power has been a popular method of energy dating back to the late 19th century.
In 2020, hydropower supplied 17% of the world's electricity, down from a high of nearly 20% in the mid-to-late 20th century. [80] [81] In conventional hydropower, a reservoir is created behind a dam. Conventional hydropower plants provide a highly flexible, dispatchable electricity supply. They can be combined with wind and solar power to meet ...
The above equation corresponds to the temperature at the exhaust of the turbine, T 5. x 5,s is the mass fraction of vapor at state 5. The enthalpy at T 5 is, , = +, This enthalpy is lower. The adiabatic reversible turbine work = H 3-H 5,s. Actual turbine work W T = (H 3-H 5,s) x polytropic efficiency
Since space is a near-vacuum, this process has close to 100% efficiency. Thermal energy is unique because it in most cases (willow) cannot be converted to other forms of energy. Only a difference in the density of thermal/heat energy (temperature) can be used to perform work, and the efficiency of this conversion will be (much) less than 100%.