California State Polytechnic University, Pomona- Building 35 Air Handling Unit Replacement and Mechanical Upgrades


This project includes the demolition of two (2) existing air handling units, installation of two (2) new air handling units, the addition of one (1) new exhaust fan, electrical power to all new equipment, hydroponic piping for chilled water and hot water connections at new equipment and distribution from new heat recovery chiller, ductwork modifications to accommodate new air handling units, integration of new equipment with the building automation system controls, start-up assistance, and review and coordination of waterside and airside TAB report.


60-ton heat-recovery chiller – 60/45 chilled water with 105/125 hot water; 30,000 cfm and 24,000 cfm dual-duct air handling units; Two (2) 5-HP chilled water pumps; Two (2) 3-HP hot water pumps; 8,000 cfm upblast exhaust fan; Other hydroponic specialties.


California State Polytechnic University, Pomona


Goss was the mechanical and electrical engineer-of-record.


Goss was the mechanical and electrical engineer-of-record for this mechanical system upgrade. Air handling units 9 and 10 were served by the campus chilled water loop and provided heat via electric reheat coils. The units were original to the building and had exceeded their useful life.

In order to work towards the carbon neutrally initiatives, the project also added a new heat-recovery chiller that takes advantage of high condenser water temperatures and supplies this heat to the hot water loop in lieu of rejecting it to the atmosphere as is commonly done in traditional air-cooled chillers and in water-cooled chillers via a cooling tower. The chiller is selected to supply 45F chilled water at a 15F delta-T while simultaneously supplying 125F hot water at a 20F delta-T. At the rated flows, this chiller is able to provide about 70% of the total chilled water and about 100% of the total hot water required at the new air handling units. This heat-recovery chiller can also supplement the campus cooling loop when Building 35 cooling loads are low. The project also added new chilled and hot water pumps to serve the new chiller, as well as new chilled water distribution piping and connection with the campus loops.

Both existing air handling units were dual-duct, and replacements were made in kind, as replacing ductwork and terminal units throughout was not economically feasible. A new exhaust fan was also provided to provide relief capacity for another air handling unit in the building. The project modified the existing ductwork to accommodate the new equipment. All new mechanical equipment required connection with the building automation system.