Steam was once considered the lifeblood of Manhattan, providing heat to thousands of apartments and buildings. Even today, Con Edison provides steam for heat and hot water to approximately 1,800 buildings in New York City. However, upkeep and an aging infrastructure has made steam a more costly utility for many buildings. Kips Bay Towers in Murray Hill is one of many high rise apartment buildings in the city that recently reconsidered its dependence on centrally-supplied steam.
Built in 1961, the two 20-story Kips Bay Towers were designed by the famed architect I.M. Pei. Located practically next door to a Con Edison station, the facility’s use of central district steam at the time was a given—and also meant that neither building was ever properly equipped for an onsite boiler plant. Although the South Tower had been constructed with a chimney, it was never actually used. When the North Tower was built, the developer avoided the construction cost of the chimney altogether, assuming that the building would always rely on Con Edison to supply steam.
Central Steam Blues
For decades, the utility supplied the towers with high-pressure steam at 180 pound-force per square-inch gauge or (psig), which was used to provide hot water for both building heat and domestic water use. The steam had to go through two separate reduction stations to bring it down to the 10 psig required by the building’s mechanical equipment. Within each tower, this lower pressure steam was piped into a shell-and-tube heat exchanger (which transfers heat from the low-pressure steam) with a hot water coil for building heat. Downstream of this heat exchanger, three pneumatic zone valves controlled heating distribution to the three zones of each building. These valves were operated by a proprietary control system, which was very complex and difficult to service.
The system’s complexity and lack of serviceability weren’t the only problems. Large amounts of high-temperature condensation were generated, which had to be disposed of somehow. New York City regulations prohibit dumping water hotter than 149°F (65°C) into the sewer system. To lower the temperature of the water and avoid wasting the heat, this condensate was piped into a separate heat exchanger and used to preheat the cold water feeding the domestic hot water tanks in each building. This removed some—but not all—of the necessary heat from the condensate. Downstream, some degree of fresh street water had to be added to the condensate just so it could be dumped into the sewer. This, however, resulted in higher water and sewer fees that even now continue to escalate. These two factors prompted Kips Bay Towers’ administration to take action.
Making Room for a Solution
Cooper Square Realty, the property management group for Kips Bay Towers, began investigating the potential benefits of a conversion from centrally-supplied steam to an on-site boiler plant. Part of this investigation involved their eligibility for the New York Energy Smart Loan Fund Program, which offers reduced interest rate financing to building owners. Once Kips Bay Towers’ eligibility was confirmed, they sought the expertise of Ralph Germain of Robert F. Germain Engineering, a firm experienced in steam conversion projects in the New York City area.