Boil, boil, toil and trouble

New boiler to increase efficiency of university’s heating and cooling

by TALLEY HENNING BROWN

Boiler number four. The new Cleaver-Brooks boiler in its new home.

Below the buildings of the south campus, three levels underground and reached by a labyrinth of stairways, are the millions of pipes, pistons and valves that keep the university engine running. Among the normal sound and fury of machinery that supplies 24-hour heat and cooling for the hundreds of radiators, hot water taps and autoclaves on campus, this fall brought a tumult of new activity — in the form of a new boiler. In an effort that required dozens of overnight workers, a wall full of permits from city agencies and the disassembly of a sizeable corner of the Power House, Plant Operations has replaced a 21-year old Nebraska waste-heat boiler with a new dual-fuel Cleaver-Brooks model. The new, more efficient boiler, which will be operational later this winter, is projected to use 25 percent less fuel compared to the replaced boiler — the investment in the boiler should pay itself off in about three to five years — and will also be necessary to power two new chillers that will serve the Collaborative Research Center upon its completion.

Rockefeller’s five boilers — three or four of which are running at any given time — provide steam that heats buildings and provides hot water and also runs a range of laboratory equipment from absorption chillers to autoclaves. Installed in 1988, the original Nebraska boiler was engineered specifically to work in conjunction with a cogenerator, a turbine generator that runs on exhaust gas from the waste-heat boiler. As the cogenerator system became more costly and less efficient to run over the years, it was taken off-line this year.

Rockefeller’s boilers can run on either oil or natural gas — depending on which is most economical at a given time — and operate at a maximum input of 30 million British thermal units (BTUs) per hour each, the maximum allowed by New York City for an institution of Rockefeller’s size. (In comparison, the average single-family residential boiler runs at about 80,000 BTUs per hour.) They consume an average of 240 billion BTUs of fuel each year. While most industrial boilers top-out at a maximum of 80 to 85 percent efficiency, the old boiler was averaging between 60 and 65 percent.

A number of cost-cutting strategies — including a well-timed renegotiation of the university’s electricity contract that saved approximately $1.3 million as well as campus-wide efforts to reduce power and fuel consumption — contributed to the savings that funded the $1.6 million purchase and installation of the boiler. Though the new boiler — boiler number four out of the five — has a slightly shorter lifespan than the university’s existing Babcock and Wilcox boilers installed in 1955, it is one-third the price of a similar B&W model. It also heats up faster and — a surprisingly important detail — it fits far more easily in the tight space afforded by the university’s boiler room.

Starting on November 19 and working through the night, Plant Ops personnel, along with a rigging crew from Boilermatic, the contractor hired to install the boiler, brought the 30-ton machine into the Power House from a flat-bed truck parked in two southbound lanes of the Franklin Delano Roosevelt Drive, which were closed to traffic. Because the size of the boiler nearly equaled the size of the entrance, the teams had first to disassemble overhead pipes to clear a passageway inside the building, and then detach the hundreds of wires and other components on the outside of the boiler’s main vessel, mapping the location of each piece for its reassembly later. Even with the massive extra effort, the crews had only about half an inch of clearance to get the boiler tank into the building. Engineers are now completing the intricate reassembly process and testing the new machine before integrating it into the system.

“What’s amazing is that after all that work, you push a button and it all works beautifully. I’m always astonished,” says Brendan Bolger, Plant Ops’ chief engineer and manager.