H. J. Patterson Hall. University of Maryland College Park.
Modernizing laboratory space within this 1930’s research facility required HVAC system replacement.
A VAV laboratory HVAC system was designed to replace the constant volume one fan per fume hood system. Laboratory supply air varies based upon room load and fume hood exhaust quantity to maintain the room pressure relationship to the adjacent space. A new air handling unit was located on the third floor with redundant exhaust fans on the roof. A run-around heat recovery system was designed to capture the exhaust air heat to pre-heat the outside air in the winter and pre-cool the outside air in the summer. The air quantities in the supply and exhaust ductwork are tracked with static pressure sensors to control the fan speeds.
Each laboratory was designed with a controller that regulates each lab’s VAV supply reheat terminal, VAV exhaust terminal, and the air flow monitoring station on the fume hood.