This letter refers to "Power Boilers in HVAC Applications," by Carl Shultz, P.E., from the September issue of ES (page 56).
The article by Mr. Schultz was both informative and easy to read. Too often, there is such little information published in the current trade magazines that is applicable to the power boilers in the HVACR field.
I noticed that Mr. Schultz made mention of parallel positioning control for power boilers in closing of the article. The firm I manage is in the process of retrofitting the major steam production plant boilers for the United States Air Force located at Hill Air Force Base in Utah.
The steam distribution system located on this base is the largest in the world owned/operated by the U.S. Air Force. There are four plants with eight, two, three, and three boilers respectively, each ranging from 40,000 pph to 80,000 pph, with installation dates ranging from 1954 to the early 1990s. The largest plant has some very unique operational criteria due to the fact that its also receives additional supply steam from a nearby incineration plant. It is nay understanding that this particular plant is extremely unique. All of the plant's boilers operate on natural gas and #2 oil. The application of the new parallel systems will also allow for the introduction of a third fuel source from a new proposed methane cogeneration plant.
Once again thank you for the publication of is article, I hope that ES will continue follow on articles about power boilers.
