HVAC Systems and Performance Flashcards
7 cards from real Certified Energy Auditor Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 HVAC Systems and Performance flashcards as text
What does the Energy Efficiency Ratio (EER) measure in a cooling system?
Answer: BTU of cooling output per watt of electrical input at a fixed condition
EER is the ratio of cooling capacity in BTU/hr to power input in watts at a single standard test condition (95°F outdoor, 80°F/67°F indoor).
In a variable air volume (VAV) system, what component modulates airflow to individual zones?
Answer: VAV terminal box with damper
A VAV terminal box contains a damper that modulates to deliver the airflow required to maintain zone setpoint temperature.
A chiller's condenser water leaving temperature is 90°F. Lowering it to 85°F will most likely have what effect on chiller efficiency?
Answer: Efficiency improves because condenser pressure drops
Reducing condenser water temperature lowers condensing pressure, reducing compressor work and improving chiller kW/ton.
Which ASHRAE Standard defines energy efficiency requirements for commercial HVAC equipment?
Answer: ASHRAE 90.1
ASHRAE 90.1, 'Energy Standard for Buildings Except Low-Rise Residential Buildings,' sets minimum efficiency requirements for HVAC, lighting, and envelope.
What is the primary purpose of a heat recovery ventilator (HRV) in a building?
Answer: Recover heat from exhaust air to pre-condition incoming fresh air
An HRV transfers heat from exhaust air to incoming outdoor air, reducing the energy needed to condition fresh ventilation air.
A rooftop unit shows a 15°F temperature split across the evaporator coil instead of the expected 20°F. What is the most likely cause?
Answer: Low refrigerant charge
Low refrigerant charge reduces the refrigerant mass available to absorb heat, lowering the evaporator's cooling capacity and temperature split.
Which metric best describes the seasonal performance of a heat pump in heating mode?
Answer: HSPF
Heating Seasonal Performance Factor (HSPF) measures total BTU of heat delivered divided by total watt-hours consumed over a heating season.