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Heat Rate (efficiency)
The efficiency of a plant is the percentage of the total energy content of a power plant's fuel that is converted into electricity. The remaining energy is usually lost to the environment as heat unless it is used for district heating. Rating efficiency is complicated by the fact that there are two different ways to measure the fuel energy input: * LCV = Lower Calorific Value (same as NCV = Net Calorific Value) neglects thermal energy gained from exhaust H2O condensation * HCV = Higher Calorific Value (same as GCV, Gross Calorific Value) includes exhaust H2O condensed to liquid water Depending on which convention is used, a differences of 10% in the apparent efficiency of a gas fired plant can arise, so it is very important to know which convention, HCV or LCV (NCV or GCV) is being used. Heat rate Heat rate is a term commonly used in power stations to indicate the power plant efficiency. The heat rate is the inverse of the efficiency: a lower heat rate is better. \tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J). Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy. Due to mass–energy equivalence, any object that has mass whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Conversion 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. Overview Energy conversion efficiency depends on the usefulness of the output. All or part of the heat produced from burning a fuel may become rejected waste heat if, for example, work is the desired output from a thermodynamic cycle. Energy converter is an example of an energy transformation. For example, a light bulb falls into the categories energy converter. \eta = \frac Even though the definition includes the notion of usefulness, efficiency is considered a technical or physical term. Goal or mission oriented terms include effectiveness and efficacy. Generally, energy conversion efficiency is a dimensionless number between 0 and 1.0, or 0% to 100%. Ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engineering Thermodynamics
Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specialized fields of engineering, each with a more specific emphasis on particular areas of applied mathematics, applied science, and types of application. See glossary of engineering. The term ''engineering'' is derived from the Latin ''ingenium'', meaning "cleverness" and ''ingeniare'', meaning "to contrive, devise". Definition The American Engineers' Council for Professional Development (ECPD, the predecessor of ABET) has defined "engineering" as: The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Conservation
Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less energy for continuous service) or changing one's behavior to use less service (for example, by driving less). Energy conservation can be achieved through energy efficiency, which has a number of advantages, including a reduction in greenhouse gas emissions, a smaller carbon footprint, and cost, water, and energy savings. Energy conservation is an essential factor in building design and construction. It has increased in importance since the 1970s, as 40% of energy use in the U.S. is in buildings. Recently, concern over the effects of climate change and global warming has emphasized the importance of energy conservation. Energy can only be transformed from one form to another, such as when heat energy is converted into vehicle motive power or when water flow's kinetic energy is converted into electricity in hydroelectr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Conversion
Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work or moving, (e.g. Lifting an object) or provides heat. In addition to being converted, according to the law of conservation of energy, energy is transferable to a different location or object, but it cannot be created or destroyed. The energy in many of its forms may be used in natural processes, or to provide some service to society such as heating, refrigeration, lighting or performing mechanical work to operate machines. For example, to heat a home, the furnace burns fuel, whose chemical potential energy is converted into thermal energy, which is then transferred to the home's air to raise its temperature. Limitations in the conversion of thermal energy Conversions to thermal energy from other forms of energy may occur with 100% efficiency. Conversion among non-thermal forms of energy m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Properties
In thermodynamics, a physical property is any property that is measurable, and whose value describes a state of a physical system. Thermodynamic properties are defined as characteristic features of a system, capable of specifying the system's state. Some constants, such as the ideal gas constant, , do not describe the state of a system, and so are not properties. On the other hand, some constants, such as (the freezing point depression constant, or cryoscopic constant), depend on the identity of a substance, and so may be considered to describe the state of a system, and therefore may be considered physical properties. "Specific" properties are expressed on a per mass basis. If the units were changed from per mass to, for example, per mole, the property would remain as it was (i.e., intensive or extensive). Regarding work and heat Work and heat are not thermodynamic properties, but rather '' process quantities:'' flows of energy across a system boundary. Systems do not ''co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cost Of Electricity By Source
Different methods of electricity generation can incur a variety of different costs, which can be divided into three general categories: 1) wholesale costs, or all costs paid by utilities associated with acquiring and distributing electricity to consumers, 2) retail costs paid by consumers, and 3) external costs, or externalities, imposed on society. Wholesale costs include initial capital, operations & maintenance (O&M), transmission, and costs of decommissioning. Depending on the local regulatory environment, some or all wholesale costs may be passed through to consumers. These are costs per unit of energy, typically represented as dollars/megawatt hour (wholesale). The calculations also assist governments in making decisions regarding energy policy. On average the levelized cost of electricity from utility scale solar power and onshore wind power is less than from coal and gas-fired power stations, but this varies a lot depending on location. Cost metrics Levelized cost o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Efficiency
In mechanical engineering, mechanical efficiency is a dimensionless number that measures the effectiveness of a mechanism or machine in transforming the power input to the device to power output. A machine is a mechanical linkage in which force is applied at one point, and the force does work moving a load at another point. At any instant the power input to a machine is equal to the input force multiplied by the velocity of the input point, similarly the power output is equal to the force exerted on the load multiplied by the velocity of the load. The mechanical efficiency of a machine (often represented by the Greek letter eta \eta) is a dimensionless number between 0 and 1 that is the ratio between the power output of the machine and the power input :\eta = \frac Since a machine does not contain a source of energy, nor can it store energy, from conservation of energy the power output of a machine can never be greater than its input, so the efficiency can never be greater than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Efficiency
The efficiency of a system in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a fractional expression), typically denoted by the Greek small letter eta (η – ήτα). : \mathrm=\frac If energy output and input are expressed in the same units, efficiency is a dimensionless number. Where it is not customary or convenient to represent input and output energy in the same units, efficiency-like quantities have units associated with them. For example, the heat rate of a fossil fuel power plant may be expressed in BTU per kilowatt-hour. Luminous efficacy of a light source expresses the amount of visible light for a certain amount of power transfer and has the units of lumens per watt. Efficiency of typical electrical devices ''Efficiency'' should not be confused with ''effectiveness'': a system that wastes most of its input power but produces exactly what it is meant to is effective but not efficient. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc. For a heat engine, thermal efficiency is the ratio of the net work output to the heat input; in the case of a heat pump, thermal efficiency (known as the ''coefficient of performance'') is the ratio of net heat output (for heating), or the net heat removed (for cooling) to the energy input (external work). The efficiency of a heat engine is fractional as the output is always less than the input while the COP of a heat pump is more than 1. These values are further restricted by the Carnot theorem. Overview In general, energy conversion efficiency is the ratio between the useful output of a device and the input, in energy terms. For thermal efficiency, the input, Q_, to the device is heat, or the heat-content of a fuel that is consumed. The des ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuel Efficiency
Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process. In the context of transport, fuel economy is the energy efficiency of a particular vehicle, given as a ratio of distance traveled per unit of fuel consumed. It is dependent on several factors including engine efficiency, transmission design, and tire design. In most countries, using the metric system, fuel economy is stated as "fuel consumption" in liters per 100 kilometers (L/100 km) or kilometer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Plant
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. Many power stations contain one or more generators, a rotating machine that converts mechanical power into three-phase electric power. The relative motion between a magnetic field and a conductor creates an electric current. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity. Low-carbon power sources include nuclear power, and an increasing use of renewables such as solar, wind, geothermal, and hydroelectric. History In early 1871 Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry. In 1878, a hydroelectric power station was designed and built by Wil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
