HVAC and Building Mechanical Systems Flashcards
6 cards from real Building Engineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 HVAC and Building Mechanical Systems flashcards as text
What does ASHRAE Standard 62.1 govern in building design?
Answer: Ventilation for acceptable indoor air quality
ASHRAE 62.1 establishes minimum ventilation rates and IAQ requirements for commercial and institutional buildings.
What refrigerant is widely used in commercial HVAC systems as a replacement for R-22?
Answer: R-410A
R-410A became the dominant replacement for R-22 in commercial split systems after the phase-out of ozone-depleting CFC and HCFC refrigerants.
What is the primary function of a Variable Air Volume (VAV) box in an HVAC system?
Answer: To modulate the volume of conditioned air delivered to a zone
A VAV box uses a damper and controller to vary airflow to each zone in response to thermostat demand, saving fan energy compared to constant volume systems.
Which heat transfer fluid is commonly circulated through chilled water HVAC systems?
Answer: Chilled water at 40–45°F
Chilled water systems circulate water cooled to 40–45°F from a central chiller to air handling units where it absorbs heat from return air.
What is the purpose of an economizer in an HVAC air handling unit?
Answer: To use outdoor air for free cooling when conditions are favorable
An air-side economizer opens dampers to bring in cool outdoor air instead of running mechanical cooling, reducing energy consumption significantly.
What unit is used to measure the cooling capacity of HVAC equipment?
Answer: Ton of refrigeration
One ton of refrigeration equals 12,000 BTU/hr and is the standard unit for rating cooling equipment capacity in the US.