Southland Industries provided design-build services and acted as the prime contractor for two new energy efficient thermal ice storage central plants with chilled and hot water underground loop piping for the Chabot and Las Positas Community College campuses. Southland was able to work on the active college campuses with 40+ year old existing buildings and non-as built underground utilities.
The Chabot site included three Ajax natural gas fired high-efficiency hot water boilers, two 650-ton high-efficiency Trane chillers with variables frequency drives (VFDs), 36 CalMac ice storage tanks with 6,840 ton-hours of cooling, and two Evapco cooling towers with VFDs located in a new central plant. The Las Positas site included a new 3,600 square foot central utility plant with two 300-ton high-efficiency Trane chillers with VFDs, 21 CalMac ice storage tanks with 3,040 ton-hours of cooling, and two Ajax natural gas fired high-efficiency boilers with future capacity. Both sites incorporated a primary and secondary chilled water pumping and distribution system with VFDs on the secondary system.
The two new central utility plants feed chilled and heating hot water throughout the collegecampuses to all buildings. The water is fed through 60,000 lineal feet of underground 12-inch chilled water mains and 10-inch heating hot water mains at Chabot, and 8-inch chilled water and 6-inch heating hot water at Las Positas.
Actual annual energy savings:
- 1,661,189 kWh/yr for cooling savings for central plant ECM, $531,580 energy rebate from PG&E.
- 122,304 therm/yr for heating savings for central plant ECM, $122,304 energy rebate from PG&E.
- 287,141 kWh/yr and 24,400 therm/yr for upgraded DDC controls ECM, $78,226 energy rebate from PG&E.