Flash Steam and Energy Loss

When flash steam is generated and vented to the surroundings, a considerable amount of energy is lost

If the condensate receiver in a steam distribution system is vented to the surroundings, flash steam will generate and evacuate, and a considerable amount of energy will be lost.

The flash steam generated depends on the initial and final pressure before and after the condensate traps for the heat exchangers. In the example - calculating generated flash steam - 0.11 kg flash steam is generated per kg condensate from a heat exchanger with 5 bar gauge pressure.

In other words 11% of the condensate is lost to the surroundings and must be replaced by feeding new water to the system.

Feeding more water requires additional heating energy and additional water treatment, increasing the total operating cost for the system.

To improve the systems efficiency, and reducing the operating cost, its common to limit the energy loss by using some kind of low pressure flash recovery systems where flash steam condensates in low temperature consumers - as heat exchangers for feeding water, air heaters and similar.

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