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Waste heat to power (WHP) is a combined heat and power (CHP) system that converts heat from an existing thermal process into electric power. These are used in energy-intensive facilities like steel mills, glass furnaces, refineries, and cement kilns.
As per the U.S Department of Energy, CHP Installation Database lists the installed WHP capacity of 938 MW at more than 100 U.S sites as of 2019.
This article discusses the working and features of waste heat to power (WHP) systems in industrial facilities.
Working of Waste Heat to Power (WHP)
WHP is referred to as the bottoming cycle configuration of the CHP system. In this system, fuel is first used to make thermal energy, and the waste heat is recovered via a heat exchanger, thus producing thermal energy. This thermal energy is used to power a turbine generator to produce electricity.
Bottoming cycle CHP system is most beneficial when used in energy-intensive industries. This system requires a heat source of sufficiently high temperatures over 500F for its efficient operation.
Features of Waste to Power (WHP) Technology
- WHP is a clean energy technology, that does not produce harmful emissions by utilizing waste heat.
- The power produced from the WHP system often displaces the electricity produced from carbon-based fuels.
- The waste heat sources that are used to drive WHP technology are:
- Waste heat from the thermal process
- Waste heat from mechanical drive
- Waste heat from other systems
The waste heat from the thermal process includes high-temperature waste heat recovered from the oven, kiln, boiler, furnace, etc.
Waste heat from mechanical drive includes low-temperature waste heat recovered from engines and gas turbine exhaust.
Waste heat from other systems is from industrial processes like fertilizer manufacturing, incineration of sewage slides, etc., which generate heat as a byproduct.
- The WHP potential for any source of waste heat is dependent on the following characteristics of the waste stream:
- The composition of the waste stream, i.e., liquid or gaseous, with or without contaminants.
- The availability of waste heat source, i.e., continuous, intermittent, or cyclic flow of the waste stream.
- The temperature and flow rate variability of the waste stream.
WHP systems are often applied in industrial applications but also have applications in commercial operations and district energy systems. The information on the feasibility and project level considerations for WHP for a facility can be found in the “Waste Heat to Power System” report, provided by the U.S. Environmental Protection Agency’s CHP Partnership.
FAQs
Waste heat to power (WHP) is a combined heat and power (CHP) system that converts heat from an existing thermal process into electric power.
WHP is referred to as the bottoming cycle configuration of the CHP system. In this system, fuel is first used to make thermal energy, and the waste heat is recovered via a heat exchanger, thus producing thermal energy. This thermal energy is used to power a turbine generator to produce electricity.
The waste heat sources that are used to drive WHP technology are:
1. Waste heat from the thermal process
2. Waste heat from mechanical drive
3. Waste heat from other systems
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