Thinking Outside Of The Box, To Stay Inside Of The Box

Twenty years ago, I was part of the design of a 10,000-ton chiller plant. 7,500 tons of which were installed on Day 1, including three chillers, three cooling towers, three chilled water pumps, and three condenser water pumps. The layout was very efficient, allowing for the easy installation of the 4th chiller, cooling tower, and pumps when needed. When the Owner required a new chiller, they decided to add capacity to the plant. Instead of one chiller, they now needed two. The original pumps were 200 HP and 250 HP horizontal split-case pumps. They were aligned in a row with a crane rail mounted directly above to aid motor replacement. The existing “box” we were in did not allow us to have two additional sets of pumps, while maintaining proper service access, in a stable parallel pumping arrangement with the efficiencies that a horizontal split-case pump has. Rotating the pumps to make them fit would prohibit the use of a crane rail, making it virtually impossible for the motors to remain in place. Changing to traditional inline pumps would allow the pumps to fit, but would drastically reduce efficiency and result in unstable parallel pumping operation. Fortunately for us, Weber Huff represents Grundfos pumps. Grundfos manufactures a vertical split-case pump that combines the space-saving benefits of an inline pump with the pumping efficiency of a horizontal split-case pump. These pumps, which are over 9 feet tall and weigh over 4,500 pounds, can now be easily accessed and maintained.

If we did not have that exact pump, the box would need to get bigger, and the downtime of the chilled water plant would have impacted the entire campus it serves. It can be difficult for engineers and Owners to embrace new concepts, but in this case, outside-the-box thinking was needed to stay inside the box.