1998 ASHRAE Technology Awards: Boiler Control Retrofit at Convent PDF

Presents a case study describing a retrofit three years ago to provide additional heat savings of 17% for a 21,400m² (230,824ft²) convent in Rochester, New York State. The structure includes a school, a convent and a nursing home. The ASHRAE Technology Award-winning retrofit implemented a new control sequence to control the heating system throughout the building. The original system was changed to a demand-oriented approach that generates only the amount of steam needed to heat the structure, thereby reducing boiler pressure below 0 psig under most load conditions. The vacuum in the boilers causes the water inside to boil at a lower temperature, and under high vacuum the boilers can produce steam at temperatures lower than 66degC (150degF) and still comfortably heat the building. Supplies a schematic of the building project.