Cogeneration


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cogeneration

[‚kō‚jen·ə′rā·shən]
(mechanical engineering)
The simultaneous on-site generation of electric energy and process steam or heat from the same plant.

Cogeneration

The simultaneous production of electrical or mechanical energy (power) and useful thermal energy from the same fuel/energy source such as oil, coal, gas, biomass, or solar panels. Conventionally, heat is emitted through cooling towers or flue gas is lost, but cogeneration makes use of that heat. A cogeneration plant is often referred to as a combined heat and power plant.

Cogeneration

The sequential production of electricity and thermal energy in the form of heat or steam, or useful mechanical work, such as shaft power, from the same fuel source. Cogeneration projects are typically represented by two basic types of power cycles, topping or bottoming. The topping cycle has the widest industrial application.

The topping cycle utilizes the primary energy source to generate electrical or mechanical power. Then the rejected heat, in the form of useful thermal energy, is supplied to the process. The cycle consists of a combustion turbine-generator, with the turbine exhaust gases directed into a waste-heat-recovery boiler that converts the exhaust gas heat into steam which drives a steam turbine, extracting steam to the process while driving an electric generator. This cycle is commonly referred to as a combined cycle arrangement. Combustion turbine-generators, steam turbine-generator sets, and reciprocating internal-combustion-engine generators are representative of the major equipment components utilized in a topping cycle. See Generator, Steam turbine, Turbine

A bottoming cycle has the primary energy source applied to a useful heating process. The reject heat from the process is then used to generate electrical power. The typical bottoming cycle directs waste heat from a process to a waste-heat-recovery boiler that converts this thermal energy to steam which is supplied to a steam turbine, extracting steam to the process and also generating electrical power. See Electric power generation

Cogeneration for building and district space heating and cooling purposes consists of producing electricity and sequentially utilizing useful energy in the form of steam, hot water, or direct exhaust gases. The two most common heating, ventilating, and air-conditioning cycles are the vapor compression cycle and the absorption cycle. See Air conditioning, Central heating and cooling

cogeneration

In a building, the on-site electric power generation utilizing both the electrical power and steam or hot water which is developed; in some municipalities in the US, if excess electrical power is generated, it may be sold to the utility.
References in periodicals archive ?
Siemens is supplying a gas and steam turbine package for the Ciner Kazan Soda combined cycle cogeneration power plant (CHP) - the largest of its kind in Turkey.
During the third week of October, the National Electric Power Regulatory Authority (NEPRA) had refused to accept the guidelines of the cogeneration policy 2008 while announcing the decision on the tariff of a cogeneration power plant.
It is time for the European Commission to consider a cogeneration target for Europe," said Fiona Riddoch, managing director of COGEN Europe.
Most of the thousands of cogeneration plants operating across the United States and Canada are small facilities operated by non-utility companies and by institutions like universities and the military.
Quinones said that the although conservation efforts like green buildings, cogeneration and cash incentives from NYSERDA (New York State Energy and Development Authority) are an important source of energy, new power plants are critically needed.
The cogeneration system providing households with both heat and electricity fits Japan where efficient use of natural resources is crucial,'' he said.
Since the late 1980s both lumber mills have shared a relationship with privately-owned Chapleau Cogeneration Ltd.
Cogeneration is a perfect choice when evaporators, dryers or pasteurizing processes require low-pressure steam, and a high-pressure boiler is available.
Rising gas prices and comparatively low electricity prices in many European countries do not paint a promising picture, as prospective investors withhold investments or become increasingly reluctant to invest in cogeneration unless they see stable policy frameworks and financial benefits that will make their investment worthwhile.
The Cogeneration for Africa project aims to help around 10 million sugar farmers and their dependants in Kenya, Ethiopia, Malawi, Sudan, Uganda, Tanzania and Swaziland, promoting more than $300 million of cogeneration investment and installing 40MW of generating power in six years.
With energy costs rising, it may be prudent for owners and developers to take a good hard look at the benefits of a cogeneration system for a new or retrofitted commercial office building.
The European Commission is due to define these (in keeping with committee procedure) on the basis of the methodology for calculating cogeneration generation efficiency and primary energy savings, as provided for in Annex III (methodology to assess the efficiency of cogeneration).