The 438 College St. project for the University of Vermont involved an addition and renovations to a 1908 era historic residence for faculty offices. The existing 3 story building is wood-framed with brick exterior walls and has a floor area of 7568 sf. The new addition is masonry with a floor area of 2299 sf.
The renovated UVM 438 College St. Building performs 46% better than the ASHRAE Standard "Energy Standard for Buildings", 90.1-2001 requirements (as modeled by computer simulation). This earns approximately 8 LEED points for energy performance. The LEED award is pending. Savings in gas consumption accounted for 34% of the total savings, while the reduction in electric consumption accounted for the remaining 66%. Of this, 56% of the electric savings was due to lowered HVAC equipment electric consumption, and 44% was due to improved lighting design.
The building is heated and cooled by a two-pipe hot and chilled water system with terminal fan coil units. The fan coils are oversized to provide quiet operation, and to provide the ability to convectively heat the offices, most of the time, without the use of fans. Chilled water is provided by a nominal 20-ton air-cooled scroll chiller, and hydronic heating is provided by two 350,000 Btuh natural gas-fired boilers. The chiller was deliberately oversized for increased efficiency. The boiler piping is primary/secondary to isolate the idle boiler from the piping system to reduce heat loss up the chimney. The system circulators have variable drives. Ventilation of the perimeter offices is by operable windows, while the remaining areas are ventilated by an energy recovery system using an enthalpy wheel. The ventilation air from this system is provided at a fixed rate to the hallways and core areas, and at a variable rate to the conference rooms and workroom (via CO2 control, pressure control and variable speed fan drives). The hallways were over ventilated to make up for the lack of mechanical ventilation being provided directly to the offices, as it was not possible to maintain the historical integrity of the interior and route ductwork to the offices.