Over the years, to meet its steam requirements, the hospital acquired two 125-hp firetube boilers in the early '60s. Two additional 125-hp firetube boilers were installed in the late '70s. Eleven years ago, a 100-hp watertube boiler was bought to provide steam for the laundry.
English knew from his previous experience that major savings could be realized by increasing the efficiency of Glenwood's heat and steam generation. The old firetube boilers at were running constantly, even though the demand for steam from the sterilizers, kitchens, and laundries was intermittent. In addition to being natural gas guzzlers, the old firetube boilers were requiring ever-larger investments in maintenance and repairs.
The Search Begins
According to Bob Sieve of Heatran Corporation in Shreveport, LA, "The driving force behind everything that they [Glenwood's staff] 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 the space heating side of his requirements with condensing/modulating hot water boilers and water heaters, but he still had steam requirements. He had personal experience with several firetube boiler brands and one watertube boiler, but he wanted to know more. He did some serious investigations at other medical centers to find out what the latest, best systems were that really would have an impact on operational flexibility and energy consumption.
There are three areas of boiler concern in the hospital - kitchen, sterilizer areas, and the laundry. The old system consisted of four large firetube steam boilers, which connected converters and steam-fired storage tank domestic water systems, directly to the kitchen and sterilizer area and then a separate watertube boiler for the laundry.
English continued, "Because of their age and configuration, the old boilers were estimated to have an in-service efficiency of somewhere between 65% to 75% - 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."
The staff chose Miura watertube boilers to replace the old boilers. "The Miuras are running at 86% to 88% efficiency. It's a tremendous difference. That's counting just when they are operating. But the advantage of the Miura boilers is that, when they are not needed, you can cycle it off and not use anything. Then you can be up and running in just six minutes," English said.
Three Miura LX50 SG dual fuel boilers were installed to supply the kitchen and sterilizer areas. The kitchen/sterilizer boilers are dual fuel - propane and natural gas - to provide back up in case of interruption in the natural gas flow. Louisiana has a law that hospitals located above certain latitudes have to have dual fuel.
‘In The Know'
Sieve decided to opt for Miura's online boiler surveillance system (MBM), which allows staff to know what is going on with its boiler and HVAC systems at all times. "We've got the controller on the boiler that tells you the alarms, but we also have the software that analyzes the information from the boilers and shows us, graphically, on a computer, the boilers' status. You can actually see what is going on with your flame and stack temperatures, etc. It gives you a lot of beneficial data. You can print out an alarm history. It tells you exactly what the alarms are about. And, we can monitor the boilers remotely," English added.He concluded, "We've seen a dramatic drop in the energy consumption over the last year. The gas prices went up. But what I can control - the energy consumption - has gone down drastically."ES
