North Carolina Museum of Art
The North Carolina Museum of Art has recently added a new wing consisting of approximately 70,000 square feet of gallery, plus more than 40,000 square feet of support space. The new wing is heated and cooled by a new state-of-the art physical plant. Two high performance centrifugal chillers operating with refrigerant R-134A do most of the work. The compressor power input at peak is less than 0.55 kW per ton.
In addition, there are two 30-ton water-to-water heat pumps that recycle waste heat from the cooling system for use by zone reheat coils.
The primary source of heat for the building is two hot-water condensing type boilers, which operate at 90% efficiency or better, depending upon the time of the year.
Chilled and hot water is circulated by centrifugal pumps with variable frequency drives. Both chilled and hot water systems are arranged as primary/secondary pumping systems.
All areas of the building are served by constant and variable air volume systems. The gallery systems are operated at constant volume to maintain precise temperature and humidity levels at all times, however variable frequency fan drives allow adjustment to system based upon operating history.
Similarly, CVRH systems are turned down at night and unoccupied periods to reduce fan cooling and reheat energy. Multiple cooling coils in major systems allow dehumidification at lower energy cost.
The main recirculation air systems are served by two dedicated ventilation air processing systems. Each system is equipped with an enthalpy wheel designed to provide heating or cooling of raw outdoor air at a 75% reduction in energy consumption. Processed ventilation air is distributed to the main air system in response to measure CO2 levels measured around the building. The pre-processing of raw outdoor air, in addition to saving cooling and heating energy, allows the main recirculation air systems to operate with dry cooling coils and at higher supply air temperature saving additional heating, cooling, and fan energy.
The architectural design of the gallery skylights allows natural daylighting while stratifying the long wave energy above the “curatorial zone.” This both reduce the need for artificial ambient light and the overall supply air quantity necessary to condition the space.
This combination of architectural and mechanical features has qualified the new wing of the North Carolina Museum of Art for 10 LEED® energy points.
Location: Raleigh, NC
Completion Date: 2010
Architects: Thomas Phifer and Partners, Pearce Brinkley Cease + Lee Architecture