The District Energy Facility (DEF) was constructed to provide utilities to an all-new brownfield campus in Allston. The building and site are constructed with resiliency and future flexibility in mind. Most of the buildings on the new Harvard campus have not yet been designed. RMF provided master planning for all mechanical and electrical systems and worked with Harvard’s Engineering & Utilities department to design a mix of equipment that can efficiently serve the buildings that will be constructed on the site, as they come on line in the future. RMF also provided site distribution systems design, as well as construction period oversight.
The chilled water generation system includes a heat recovery chiller that can provide simultaneous low temperature hot water and chilled water, two 2,500 ton medium voltage variable speed centrifugal chillers (with space for 5 more), two 650 ton free cooling heat exchanger, and a 14,000 ton-hour, 1.35 MG thermal energy storage tank. Rainwater and cooling coil condensate from campus AHUs are recovered in a cistern, then filtered and used as cooling tower makeup.
LocationBoston, Massachusetts
ServicesDistrict Energy, Thermal & Electrical Utilities, Energy & Decarbonization
MarketHigher Education
Low temperature heating water is also provided by condensing 20,000,000 & 6,000,000 BTUH gas boilers (3 today, with space for 5 more), some of which can also operate on ultra-low-sulfur diesel fuel in standby.
The electrical substation located in the plant provides a looped power supply to all campus buildings, backed up by a pair of 2 MW standby engine generators. Normal power is available from two 2.5 MW reciprocating gas cogeneration engine generators, which also supply low temperature heating water.
Due to the high-water table on the site, HDPE piping was chosen for the distribution. The thermal utilities are installed in a common trench with electric ductbank, in a looped arrangement sized to accommodate the full build out of the campus.
Highlights
Two 2,500 ton medium voltage (13.8 kV input/4 kV output) variable speed centrifugal chillers
1.34 million gallon thermal energy storage tank, providing 14,000 ton-hours of chilled water storage
Heat recovery chiller
Two 2 MW standby diesel generators
2.5 MW gas reciprocating engine with heat recovery for base loaded combined heat and power
Two 650 ton free cooling heat exchangers and pumps
In total, the DEF will house 13.5 MW of power output, 146 MMBTU/HR of heating and 17,500 tons of cooling
Utility Distribution
2,000 LF of new twelve-way underground electric ductbanks with 3-500 kcmil, MV-105 15 kV cabling and 4/0 600 V ground and manholes
3,000 LF of 34 inch HDPE chilled water supply and return piping
3,000 LF of 24 inch HDPE-RT hot water supply and return piping