CEA Lighting & HVAC Energy Analysis 3

Question 1

Which ASHRAE standard provides minimum energy efficiency requirements for commercial building HVAC and lighting systems in the US?

Accepted Answer

ASHRAE 90.1

Answer

ASHRAE 90.1 sets minimum energy efficiency standards for commercial buildings, including prescriptive LPD limits and HVAC efficiency requirements.

Question 2

An air handling unit has a supply fan with a brake horsepower (BHP) of 15 and operates 4,000 hours per year. At $0.10/kWh, what is the approximate annual fan energy cost? (1 HP ≈ 0.746 kW)

Accepted Answer

$4,476

Answer

15 BHP × 0.746 kW/HP × 4,000 hr/yr × $0.10/kWh = $4,476.

Question 3

What does the term 'economizer mode' mean for an HVAC air-side system?

Accepted Answer

Using outdoor air for free cooling when conditions are favorable

Answer

Air-side economizers bring in outdoor air to cool the building without mechanical refrigeration when outdoor conditions are cool and dry enough.

Question 4

A luminaire delivers 3,500 lumens using 35 watts. What is its efficacy?

Accepted Answer

100 lm/W

Answer

Efficacy = lumens ÷ watts = 3,500 ÷ 35 = 100 lm/W.

Question 5

Which control strategy reduces HVAC fan energy by lowering airflow during periods of reduced cooling or heating demand?

Accepted Answer

Variable air volume (VAV)

Answer

VAV systems modulate airflow to match zone loads, saving fan energy through the cube law relationship between fan speed and power.

(CEA) Certified Energy Analyst Practice Test

(CEA) Certified Energy Analyst Practice Test

CEA Lighting & HVAC Energy Analysis 3