Trigeneration
Encyclopedia
Trigeneration, also called CCHP (combined cooling, heat and power), refers to the simultaneous generation of electricity, useful heating and useful cooling from the same original heat source such as fuel or solar energy. Waste heat
insufficient in energy to produce electricity through mechanical means, such as through a steam turbine
, contains usable energy that is harnessed for thermal regulation purposes as described in cogeneration
. Trigeneration differs from cogeneration
in that some of the waste heat
is used for cooling. CCHP systems can attain higher efficiencies per unit fuel than cogeneration
or traditional power plants.
A modern American acronym is BCHP, Building Cooling, Heating and Power, for trigeneration applications in buildings.
where a percentage of the heat byproduct is used for cooling. Heating and cooling output may operate concurrently or be interchanged based need and system construction.
A power plant operating on the basis of the Carnot cycle
will convert energy from heat to mechanical energy based on a temperature differential as described by the Rankine cycle
. Mechanical energy is converted into electrical power by an electric generator. Waste heat
which is insufficient in energy as input to the electric generator is then recycled for other purposes such as heating or cooling of living space or industrial facility or as input to other industrial processes. Cooling is achieved through an absorption chiller or an adsorption chiller as the original byproduct is heat.
in a trigeneration system is defined as:
Where:
= Thermal efficiency
= Total work output by all systems
= Total heat input into the system
Typical trigeneration models have losses as in any system. The energy distribution below is represented as a percent of total input energy :
Conventional thermoelectric stations convert only about 33% of the fuel energy into electricity. The rest is lost in the form of heat. The adverse effect to the environment from this waste suggests a need to increase the efficiency of electricity production. One method for more efficient production of electricity is the cogeneration
or trigeneration of heat cooling and power, where more than 80% of the fuel's energy is converted into usable energy, resulting in both financial and environmental benefits.
. Redundancy of power in mission critical applications, lower power usage costs and the ability to sell electrical power back to the local utility are a few of the major benefits.
Most industrial countries generate the majority of their electrical power needs in large centralized facilities with capacity for large electrical power output. These plants have excellent economies of scale, but usually transmit electricity long distances resulting in sizable losses, negatively affect the environment. Large power plants can use cogeneration or trigeneration systems only when sufficient need exists in immediate geographic vicinity for an industrial complex, additional power plant or a city. An example of cogeneration
with trigeneration applications in a major city is the New York City steam system
.
Waste heat
Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...
insufficient in energy to produce electricity through mechanical means, such as through a steam turbine
Steam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
, contains usable energy that is harnessed for thermal regulation purposes as described in cogeneration
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
. Trigeneration differs from cogeneration
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
in that some of the waste heat
Waste heat
Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...
is used for cooling. CCHP systems can attain higher efficiencies per unit fuel than cogeneration
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
or traditional power plants.
A modern American acronym is BCHP, Building Cooling, Heating and Power, for trigeneration applications in buildings.
Details
Trigeneration (CCHP) is defined as the extraction of electrical power and heat from fuelFuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
where a percentage of the heat byproduct is used for cooling. Heating and cooling output may operate concurrently or be interchanged based need and system construction.
A power plant operating on the basis of the Carnot cycle
Carnot cycle
The Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by Benoit Paul Émile Clapeyron in the 1830s and 40s. It can be shown that it is the most efficient cycle for converting a given amount of thermal energy into work, or conversely,...
will convert energy from heat to mechanical energy based on a temperature differential as described by the Rankine cycle
Rankine cycle
The Rankine cycle is a cycle that converts heat into work. The heat is supplied externally to a closed loop, which usually uses water. This cycle generates about 90% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants. It is...
. Mechanical energy is converted into electrical power by an electric generator. Waste heat
Waste heat
Waste heat sometimes called Secondary heat or Low-grade heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found. Energy is often produced by a heat engine, running on a source of high-temperature heat...
which is insufficient in energy as input to the electric generator is then recycled for other purposes such as heating or cooling of living space or industrial facility or as input to other industrial processes. Cooling is achieved through an absorption chiller or an adsorption chiller as the original byproduct is heat.
Thermal efficiency
Thermal efficiencyThermal efficiency
In thermodynamics, the thermal efficiency is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, a boiler, a furnace, or a refrigerator for example.-Overview:...
in a trigeneration system is defined as:
Where:
= Thermal efficiency = Total work output by all systems = Total heat input into the systemTypical trigeneration models have losses as in any system. The energy distribution below is represented as a percent of total input energy :
- Electricity = 45%
- Heat + Cooling = 40%
- Heat Losses = 13%
- Line Losses = 2%
Conventional thermoelectric stations convert only about 33% of the fuel energy into electricity. The rest is lost in the form of heat. The adverse effect to the environment from this waste suggests a need to increase the efficiency of electricity production. One method for more efficient production of electricity is the cogeneration
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
or trigeneration of heat cooling and power, where more than 80% of the fuel's energy is converted into usable energy, resulting in both financial and environmental benefits.
Distributed generation
Trigeneration has its greatest benefits when scaled to fit buildings or complexes of buildings electricity, heating and cooling are perpetually needed. Such installations include but are not limited to: data centers, manufacturing facilities, universities, hospitals, military complexes and colleges. Localized trigeneration has addition benefits as described by distributed generationDistributed generation
Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
. Redundancy of power in mission critical applications, lower power usage costs and the ability to sell electrical power back to the local utility are a few of the major benefits.
Most industrial countries generate the majority of their electrical power needs in large centralized facilities with capacity for large electrical power output. These plants have excellent economies of scale, but usually transmit electricity long distances resulting in sizable losses, negatively affect the environment. Large power plants can use cogeneration or trigeneration systems only when sufficient need exists in immediate geographic vicinity for an industrial complex, additional power plant or a city. An example of cogeneration
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
with trigeneration applications in a major city is the New York City steam system
New York City steam system
The New York City steam system is a district heating system which takes steam produced by steam generating stations and carries it under the streets of Manhattan to heat, cool, or supply power to high rise buildings and businesses...
.
Applications in non-renewable power generation systems
Any of the following conventional power plants may be converted to a CCHP system :- Coal
- Natural Gas
- Oil
- Nuclear
- Microturbines
- Small gas turbines
External links
- http://www.youtube.com/watch?v=o0L6dqH5qpI&NR=1 3D model of installed commercial trigeneration system
- http://www.youtube.com/watch?v=vHLKKd04hfk Absorption chiller animation
- http://www.trigeneration.eu European site on trigeneration
- http://www.eco-maxchillers.com/common/Content.asp?PAGE=362&CONTENT=865 Commercial absorption chiller for trigeneration
- http://www.2g-cenergy.com/trigen-more.html Commercial trigeneration system
- http://www.marathonengine.com/ecopower_principles.html Commercial trigeneration system
See also
- CogenerationCogenerationCogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
- Distributed generationDistributed generationDistributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
- Carnot cycleCarnot cycleThe Carnot cycle is a theoretical thermodynamic cycle proposed by Nicolas Léonard Sadi Carnot in 1824 and expanded by Benoit Paul Émile Clapeyron in the 1830s and 40s. It can be shown that it is the most efficient cycle for converting a given amount of thermal energy into work, or conversely,...
- Rankine cycleRankine cycleThe Rankine cycle is a cycle that converts heat into work. The heat is supplied externally to a closed loop, which usually uses water. This cycle generates about 90% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants. It is...
- Micro combined heat and power
- New York City steam systemNew York City steam systemThe New York City steam system is a district heating system which takes steam produced by steam generating stations and carries it under the streets of Manhattan to heat, cool, or supply power to high rise buildings and businesses...
- Renewable energy in AustraliaRenewable energy in AustraliaRenewable energy in Australia represents 5.2% of total energy consumption, but only 1.7% of total production, the difference being the result of significant non-renewable energy exports. In the five years to 2009 renewable energy consumption grew by 3.5%, faster than other energy sources. Of all...