Beekman Point Engineering (BPE) was the design project leader for mechanical, electrical, and construction administration services. The scope of this project was mainly to upfit both the chilled and heating hot water systems to more reliable designs along with replacing all the existing air-side equipment. BPE conducted a thermal analysis of the 3-building complex and modeled the building and HVAC systems
to best understand the heating and cooling load profile, identify any existing system operational/control deficiencies, and provide the basis of new equipment sizing.

During this effort, BPE identified that the existing chiller plant had a load gap in operational performance between the 25-ton pony air-cooled chiller maximum capacity and the 215-ton water-cooled chiller minimum stable operating capacity. Through 8,760-hour HVAC load modeling and simulation, the team was able to identify winter months when the chiller plant would operate at a varying load between 30 and 60 tons of capacity; however, the existing chilled water plant would not operate at a stable condition during this loading which was causing chiller plant shutdowns due to chiller operational limitations. Without the owner approval to replace or significantly modify the chiller plant to operate reliably throughout the entire year, BPE further analyzed the existing system and controls for available options that met the budgetary constraints. The agreed upon solution involved primarily adding a strategy for best maintaining condenser water loop temperature during the winter months using a new variable speed pump and piping arrangement with mixing valve controls; secondarily adding a chilled water side buffer tank to increase system inertia.