CEA Lighting & HVAC Energy Analysis 5

Question 1

A building energy model shows an annual cooling load of 500,000 ton-hours. If the chiller plant average efficiency is 0.65 kW/ton, what is the annual chiller electricity consumption?

Accepted Answer

325,000 kWh

Answer

Annual energy = 500,000 ton-hr × 0.65 kW/ton = 325,000 kWh.

Question 2

What is the primary advantage of a thermal energy storage (TES) system in a commercial building?

Accepted Answer

It shifts cooling energy use to off-peak hours to reduce demand charges

Answer

TES systems generate cooling during off-peak hours and store it, reducing peak demand charges and taking advantage of lower off-peak electricity rates.

Question 3

According to ASHRAE 90.1, what automatic controls are required for exterior lighting in commercial buildings?

Accepted Answer

Both time-of-day scheduling and photosensor (daylighting) controls

Answer

ASHRAE 90.1 requires exterior lighting to be controlled by both a time-of-day schedule and a photosensor to ensure lights extinguish during daylight hours.

Question 4

Which of the following best describes 'infiltration' in the context of building HVAC energy loads?

Accepted Answer

Uncontrolled air leakage through envelope gaps and cracks

Answer

Infiltration is unintentional air leakage into or out of a building through gaps in the envelope, adding heating or cooling load depending on outdoor conditions.

Question 5

A photoelectric dimming system reduces lighting to 40% of full output when daylight is sufficient. The connected load is 10 kW and the system dims for 1,500 hours per year. How many kWh are saved annually compared to full-output operation?

Accepted Answer

9,000 kWh

Answer

At 40% output, 60% of energy is saved; 10 kW × 0.60 × 1,500 hr = 9,000 kWh saved annually.

(CEA) Certified Energy Analyst Practice Test

(CEA) Certified Energy Analyst Practice Test

CEA Lighting & HVAC Energy Analysis 5