Energy Auditing & Assessment Techniques Flashcards
7 cards from real CEA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Energy Auditing & Assessment Techniques flashcards as text
Infrared thermography during an energy audit is most effective for identifying:
Answer: Insulation voids, moisture intrusion, and thermal bridging in the building envelope
Infrared cameras detect surface temperature differences that reveal missing insulation, air leakage, and moisture—all of which degrade envelope performance.
In motor systems assessment, what is the significance of measuring 'motor load factor'?
Answer: It reveals whether a motor is oversized for its application, indicating downsizing or VFD opportunities
A motor running at low load factor (below 50%) wastes energy; right-sizing or adding a VFD can dramatically reduce consumption.
A retro-commissioning (RCx) study differs from a traditional energy audit primarily because RCx:
Answer: Focuses on optimizing existing systems to restore original design performance without capital upgrades
Retro-commissioning identifies operational deficiencies in existing equipment (e.g., simultaneous heating and cooling) and corrects them for low/no-cost savings.
When auditing a compressed air system, which condition represents the GREATEST source of energy waste?
Answer: System leaks, which can account for 20–30% of compressor output
Compressed air leaks are the single largest waste source in industrial systems, often wasting 20–30% of total compressed air production.
During an HVAC audit, the auditor finds an air handling unit with simultaneous heating and cooling (hot deck/cold deck mixing). The recommended corrective action is to:
Answer: Reset the hot deck and cold deck temperatures using an outdoor air reset schedule to minimize mixing
Optimizing hot and cold deck temperature reset schedules reduces simultaneous heating/cooling energy waste, a classic low-cost retro-commissioning measure.
A 'degree-day analysis' is used in energy auditing to:
Answer: Normalize heating and cooling energy consumption against outdoor temperature variation across years
Degree-day normalization allows auditors to compare energy use across different weather years and separate weather-related variation from operational changes.
The 'simple payback period' for an energy conservation measure (ECM) is calculated as:
Answer: Initial capital cost divided by annual energy cost savings
Simple payback = Capital Cost ÷ Annual Savings; it is a quick screening metric but ignores time value of money and equipment life.