General Overview
The steam condensate recovery system is responsible for collecting condensate from the steam distribution system through steam tramps and recovering waste heat. The condensate returned to the boiler is typically passed through a deaerator to remove unwanted oxygen before the condensate reaches the boiler. Additionally, since condensate is purified water at high temperatures it can reduce the amount of fuel fed into the boiler as well as the water treatment costs for the makeup water.
Condensate Recovery Components
Condensate recovery systems are typically equipped with pumps, pipe networks, and a heat exchanger. Condensate is passed into a receiver tank. The components of a condensate recovery system are shown in Figure 1.
Condensate Pumps
Condensate pumps are responsible for moving condensate from the receiver tank(s) back to the boiler system. In some cases, the receiver tank, pump, and float controls are packaged together. An appropriately sized pump is crucial to avoiding condensate build up which could create problems with terminal units.
Pipe Networks
The pipe network of a condensate recovery system transports flash steam and condensate. Designs should consider differential of pressure between different lines. It is usually covered with insulation material to minimize heat losses with the environment.
Evaluation of Energy Consumption
The primary effect of the condensate recovery system on the steam plant is to minimize heat losses and manage condensate that could otherwise be damaging to the steam plant. Generally, the energy related to the condensate system is not quantified; instead, the energy consumption of the overall low-pressure steam plant is quantified. For more information, see Steam Plant.
Further Reading
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ASHRAE (2014). “ASHRAE Guideline 14-2014 – Measurement of Energy, Demand, and Water Savings.” Annex A.
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ASHRAE (2020). “ASHRAE Handbook: HVAC Systems and Equipment,” Chapter 11. STEAM SYSTEMS. I-P Edition.
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U.S. Department of Energy. (2014). “A Sourcebook for Industry – Energy,” https://www.energy.gov/sites/prod/files/2014/05/f15/steamsourcebook.pdf