A common problem with HRSG economizers is tube leaks caused by excessive differential temperatures between adjacent tubes. Additional common problems are economizer under-performance due to stagnant water flow and water hammer caused by trapped air or steam. HRSG cycling increases the risk of these problems.


The patented HRST ShockMaster® Economizer avoids these common problems. The ShockMaster Economizer design allows uniform upward water flow through the tubes, causing uniform temperatures across each tube panel, minimizing pressure part stress. This leads to excellent low-load performance, and is a good option for cycling HRSGs. Also, the ShockMaster Economizer design allows complete venting prior to start-up. The up flow through the tubes and complete ventability avoid water hammer and stagnant flow. The ShockMaster Economizer design is available as a complete retrofit replacement or as a field modification for some existing economizer designs.

HRST ShockMaster® Economizer Case Study


In 2006, Ken MacKenzie, Project/Engineering Manager for the City of Medicine Hat, Alberta, Canada, expressed frustration to HRST, Inc. regarding the reliability of his HRSG economizers. The facility experienced routine tube leaks that led to costly outages for the plant. HRST analyzed the problem and recommended a new design for an economizer that addressed the design deficiencies of traditional economizers.

The Solution:

The new design, dubbed the ShockMaster, directly addressed the inherent design deficiencies that have plagued economizers for decades. Initially, one ShockMaster was installed as a trial. The new design proved so effective at solving the problem, The City of Medicine Hat ordered three additional ShockMasters to be installed. A fifth ShockMaster was later ordered for insertion into a new HRSG.

The Result:

HRST, Inc. managed to solve a significant design problem for The City of Medicine Hat that has the potential to benefit any other energy facility. Ken MacKenzie, Project/Engineering Manager for the City of Medicine Hat, does not mince words when he speaks about his satisfaction with the ShockMaster. “We struggled, as a facility, with the traditional economizer design. HRST, Inc. analyzed the problem and came up with a revolutionary new economizer design that solved the issues of unnecessary economizer expense and downtime for our facility. I would recommend this solution to any energy facility with a similar need. It really works . . . we see it working for us every single day.”

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ShockMaster® is a registered trademark of HRST, Inc.
HRST ShockMaster® Economizer, U.S. Patent No. 7,621,237.