PE PDH
PDH Online

Energy Recovery for Ventilation Air in Laboratories


Quiz Questions

1.A basic, manifolded exhaust system, with a primary fan and a backup unit in a common duct system, has higher energy efficiency than multiple, dedicated fans working independently.
True
False
2. Mani folded exhaust systems save energy in four ways-

  • Reduces fan power, in part due to less pressure drop in duct work.
  • Provides an adjustable airflow system that can modulate energy needs in response to a varying requirement.
  • Requires less energy to disperse exhaust plumes due to increased dilution and momentum of effluent.
  • Increases energy recovery opportunities.
True
False
3.Manifolded exhaust systems reduce the number of fans and the ductwork needed when compared to individual fume hood exhaust systems. Therefore, less energy is used to move the exhaust air, due to consolidation of numerous small fans into a larger and more efficient fan, and the reduction of ductwork pressure drop with larger dimension ductwork.
True
False
4. Manifolded exhaust systems can be less costly than individual systems due to less material and installation labor. Fewer fan ducts, ceiling and roof penetrations, electrical connections, and exhaust terminals typically yield a smaller first-cost capital investment.
True
False
5.A manifolded exhaust system _______________________ the opportunity to recover energy contained in the conditioned air stream that is being exhausted from the laboratories.
Maximizes
Minimizes
6.The larger the number of fume hoods, the greater the operating and installation economy that can be realized from a manifolded system.
True
False
7. Specialized axial-type exhaust fans are available for constant or variable air volume manifolded exhaust systems. These fans are designed to move large amounts of ambient air into the exhaust plume as it is discharged from their stacks at a high upward velocity. The induced ambient air provides additional dilution. The high plume velocity reduces the tendency for wind to push the exhaust back down toward the building. However, these specialized induced-air fans require higher energy use, since they flow larger amounts of air in order to increase exit plume velocity.
True
False
8.Manifold ductwork can be arranged to serve all or specific groupings of laboratories and their fume hoods, typically on a particular floor or in a wing of a building.
True
False
9.Good manifolding design practice is illustrated in _________________________.
Figure 2
Figure 3
10.The operation of a stepped fan uses multiple fans and stacks connected to a common plenum. It provides necessary stack exit velocity & uses less fan energy in smaller diameter stacks.
True
False