18. The person responsible for selecting control valves, coordinating them with heat transfer devices, and providing a schedule of devices and a detailed connection schematic is which of the following?
A. architect
B. HVAC designer
C. project engineer
19. This type of diffuser features a series of openings arranged in a radial pattern around the center of the diffuser face.
A. slaque-face 
B. square
C. swirl
20. A common application to compare retrofit alternatives for existing buildings is which of the following?
A. plug loads
B. energy modeling
C. building orientation