|Project Name:||Whittemore Hall|
|Owner:||Tuck School of Business at Dartmouth College|
|Project Application:||Dormitory for Tuck Students|
|Equipment:||Energy Recovery Unit|
The Tuck School of Business at Dartmouth College in New Hampshire was founded in 1900. Given this long-standing tradition in the study of economics and business administration, it is no surprise that the design of its newest graduate student residence would employ a state-of-the-art HVAC system to produce a healthy, comfortable living environment for its occupants, while delivering an annual return on investment that will eventually allow it to pay for itself.
Whittemore Hall is the focal point for residential and community life for both full time MBA students and executive program participants. The four-story building consists of 60 private rooms, each with its own bath, 10 group study rooms, 3 conference rooms and a distance learning suite all organized around a central, common living room to foster a sense of community and teamwork.
The Invisible Hand
It was the college’s intention to make the building as energy efficient as possible. To this end, the project was developed by Marc Rosenbaum, P.E. from Energysmiths and BR + A, the MEP consulting firm from Boston. The overall concept called for an energy recovery air handling unit using an enthalpy wheel to supply 100% outside air to the bedrooms, while a more traditional VAV system served the public areas of the building. The design of the HVAC system was further complimented by an extremely tight building envelope to reduce energy losses through air leakage, and by the use of triple glaze, low-e glass on the building’s many windows. Based on prescriptive ventilation requirements dictated by ASHRAE 62-1999 it was judged that 14,700 CFM of outside air would be required in order to maintain an acceptable level of indoor air quality for the students. The decision was also made to use the exhaust air coming from the bathrooms to maximize the latent recovery.
The energy recovery air handling unit was supplied by Annexair, a Montreal based air handling unit manufacturer. Every aspect of the energy recovery unit was constructed in accordance with the schools overall design philosophy. “It was really nice to see a project like Whittemore, because it indicated to us that designers and specifiers are finally starting to realize that a truly energy efficient design requires a manufacturer that specializes in the these types of packaged units. We provided 2-inch double-wall construction, backward inclined fans with airfoil blades, premium efficiency motors, a steam preheat coil, a chilled water coil and of course a high performance energy recovery wheel.” The benefit of this type of comfort-to-comfort application is that energy can be conserved during both the summer and winter months. Based on a bin analysis for Hanover, NH the use of the wheel results in a significant savings of $10,050 in annual heating and cooling costs for the facility. One other important feature to note is the ability to significantly downsize the capacity of other HVAC components. In this case, we were able to reduce the total cooling required by approximately 42 tons.
Results from past heating seasons have exceeded expectations. Bo Peterson relates, “One winter morning, with an outdoor ambient of 5°F, the unit supplied 55°F air without opening the steam valve to the steam coil.” Given that testimony, it is apparent that the college has made a wise investment.