The Shocking Truth About Steam’s Efficiency

This 6,000,000 BTU 220°F hot water plant is replacing a 13,000,000 BTU 100 PSI steam plant.

Steam is Yesterday
Using steam to create heat is the equivalent of using an incandescent bulb to create light. So why do engineers continue to use steam? The most common response is: “because we’ve always done it that way.” This blog briefly explains the shocking inefficiency of steam plants, and why hot water should always be utilized when possible.

Just How Inefficient is Steam? 
When evaluating the efficiency of a steam plant, the real efficiency is a ratio of the steam produced to the energy consumed. Burner efficiency is not a measure of the boiler plant’s efficiency. Typically, for the fuel consumed, the most efficient steam systems only produce 60-70% usable steam. We have measured many plants that hover around 50% efficiency.

Blowdown, makeup water, and part load boiler operation all contribute to the steam plant’s inefficiency. In addition, once the steam leaves the boiler plant, vast amounts of BTUs are often wasted before it reaches the intended use—through uninsulated pipes and components. Leaky steam traps send raw steam back to the boiler plant without releasing its energy for productive use. In the majority of plant surveys that we perform and meter, it’s rare that a factory will get 50% utilization of the fuel expended, and we’ve measured plants that are as low as 25%! For this reason, you should only use steam when there is no alternative.

The Alternative
A classic misuse of steam is in heat exchangers designed to heat fluid. The better alternative is a closed loop hot water system, which typically operates at greater than 90% efficiency. These can be used for applications in which the heating requirements are as high as 230°F.

It would be wise to take a hard look at how your steam is being used!