Modifying Engine Exhaust for Savings
-- Consulting-Specifying Engineer, 1/1/2001
Electric and steam-turbine drives for chillers are common practice. However, the use of gas-engine-driven chillers, particularly in a high-rise city building, is unique.
When it came to a chiller retrofit for the Time & Life building in Manhattan, this selection required an analysis of the gas-engine exhaust, noise and vibration potential and the cooling tower and riser capacity. Because Time & Life is a high-rise building, it was decided that engine exhaust-even though the fuel was natura rather than diesel-had to be discharged at the roof. And even though there was a setback at the 8th floor, the possibility of discharging engine exhaust with the "canyon" effect of adjacent buildings drawing the exhaust to street level was considered an unnecessary risk.
The engine exhaust had to be discharged at the 49th floor roof, and it wasn't possible to find a similar condition on which to base the exhaust back-pressure calculations. Therefore, these ideas needed to be confirmed with an outside expert; RWDI, Toronto, Canada was chosen.
Engineers from Atkinson Koven Feinberg Engineers, LLP, New York City, developed 3D CAD drawings and gave them to the team from RWDI, who, in turn, generated the necessary data. The results and some further review directed the AKF engineers to reduce the exhaust riser by one pipe size. On a project of this size, the savings were considerable.
