We Need More Steam

Glenwood started as a community hospital back in the 1960s. Now it is a regional medical center with a 257-bed hospital.

The hospital installed two 125-hp York Shipley fire tube boilers in the early 1960s. Two 125-hp Cleaver Brooks fire tube boilers were installed in the late 1970s. In 1993, a 100-hp Fulton water tube boiler was installed to provide steam for the laundry.

English knew from previous experience that major savings could be realized by increasing the efficiency of Glenwood's heating and steam generation systems. The old fire tube boilers were running constantly, even though the demand for steam from the sterilizers, kitchens, and laundries was intermittent. In addition, the old boilers were requiring more and more maintenance and repair.

"Because of their age and configuration, the old boilers were estimated to have an in-service efficiency of somewhere between 65 to 70 percent," English said, "if they were tuned-up properly. We had to run our old boilers all the time because it would take at least 30 minutes to get them up and running."

When contractor Bob Sieve of Heatran Corp., Shreveport, La., started working with Glenwood Medical Center two years ago, "They were in the process of completely modernizing their boiler plant," he said. "The driving force behind everything they do over there is to conserve natural gas because of the pricing that we are experiencing now. We specialize in energy-related retrofits."

English decided to meet his space-heating requirements with condensing/modulating hot water boilers and water heaters, but he still had those steam requirements. He researched other medical centers to find out what they were using.

The steam boiler design chosen to replace Glenwood's old boilers is very different from any of the steam boilers in English's plant operation background. Miura Boilers' North American water tube boilers (manufactured in Brantford, Ontario) are made of North American steel, Honeywell (Morristown, N.J.) controls, and Grundfos (Fresno, Calif.) pumps.

Efficiency Upgrade

According to the manufacturer, a 100-hp Miura's surface area "will radiate a constant amount of heat whether the boiler runs at 100 percent of capacity or at 10 percent of capacity."

The lower the use of its capacity, the company said, the higher the ratio of radiation loss to usable steam production.

Floating headers make the boilers' small size and water capacity possible, without creating thermal shock to the boilers' water tubes and enclosure, the company said. These headers allow the tubes to be short and straight.

Additional savings result from the boilers' fast startup capability. "Most boilers are turned down, but not off, when steam demand drops," the manufacturer explained. "Miuras go from a cold start to steam in five minutes."

English compared the difference in operating efficiencies. "The old boilers we were running were in the 65- to 70-percent efficiency range," he said, "if they were tuned-up properly. The Miuras are running at 86- to 88-percent efficiency. That's just counting when they are operating. When they are not needed, you can cycle [them] off and not use anything."

Three LX-50 SG dual-fuel boilers were installed to supply the kitchen and sterilizer areas. According to Sieve, "The demand for steam was a little bit more than one 50-hp boiler could handle; that's the reason we put in three - two to handle the load and one as backup.

"The Miura portion of this project is furnishing steam for the kitchen and for the sterilizers," he said.

"Now we're in the process of replacing the boilers in the laundry, which will have two LX-100 SG natural gas units. This will be installed before the end of the year." The kitchen/sterilizer boilers are dual fuel (propane and natural gas) to provide a backup in case of interruption to the natural gas supply.

Maintenance

Sieve said he is pleased with the Miura Boiler Maintenance (MBM) system, an online surveillance system. "There is an overwhelming trend in business - whether you are in the boiler business, air conditioning, or whatever - to be able to know what is going on with your systems at all times."

"We've got the controller on the boiler that tells you the alarms, but we also have software that analyzes the information from the boilers and shows us the boilers' status," English said.

"You can actually see what is going on with your flame and stack temperatures. You can print out an alarm history. It tells you exactly what the alarms are about. And we can monitor the boilers remotely."

The operator can monitor three aspects of boiler feedback. Alarms include various flame, water level, power, temperature, and pressure alarms. Cautions include times reminded about filters, blowdowns, softeners, batteries, sensors, etc. The combustion history records cycles, low and high firing, blowdowns, and blower and pump cycles.

According to English, "The gas price went up, but what I can control - the energy consumption - has gone down drastically."

For more information, contact Mark Utzinger, Miura Boiler Inc., 600 Northgate Pkwy, Ste. M, Wheeling, IL 60090-3201; 847-465-0001; 847-465-0011 (fax); chicago@miuraboiler.com; www.miuraboiler.com.

Publication date: 09/13/2004