Energy Audits Flashcards
7 cards from real EMP 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 Audits flashcards as text
An energy auditor discovers a facility's compressed air system operates at 120 psi but most end uses only require 90 psi. The BEST recommendation is to:
Answer: Reduce system pressure to the minimum required level
Reducing compressed air pressure by 2 psi saves approximately 1% in compressor energy, so dropping from 120 to 90 psi can yield roughly 15% savings.
In the context of energy audits, what does 'demand charge' refer to on a utility bill?
Answer: A fee based on the highest rate of power draw during the billing period
Demand charges are based on the peak power demand (kW) during a billing period, often the highest 15- or 30-minute average, and can represent 30–70% of a commercial electricity bill.
Which heat transfer mechanism is responsible for the majority of heat loss through a well-insulated opaque wall assembly?
Answer: Conduction through the solid materials
In a well-insulated opaque wall, conduction through the solid materials (studs, insulation, sheathing) is the dominant heat transfer mechanism.
A facility manager wants to evaluate the thermal performance of a roof during an energy audit. Which diagnostic tool provides a non-destructive assessment of insulation defects and moisture intrusion?
Answer: Infrared thermography
Infrared thermography detects temperature differences on roof surfaces that indicate missing insulation, thermal bridging, or moisture-saturated insulation without destructive testing.
When auditing a steam distribution system, auditors should pay particular attention to steam traps because failed-open traps result in:
Answer: Continuous steam blowthrough, wasting significant boiler energy
A steam trap failed open allows live steam to pass continuously into the condensate return, bypassing useful heat delivery and wasting substantial boiler fuel.
During an energy audit, a facility's cooling tower is found to have a 'cycles of concentration' of 2. Increasing this to 5 would primarily achieve which benefit?
Answer: Decrease makeup water consumption and associated energy for water treatment
Higher cycles of concentration mean less blowdown and less makeup water needed, reducing water costs and the energy required to pump, treat, and heat incoming water.
What is the significance of 'regression analysis' in energy auditing?
Answer: It develops a mathematical model relating energy use to independent variables like weather and production
Regression analysis creates a baseline energy model correlating consumption to drivers like heating degree days or production volume, enabling accurate measurement and verification of savings.