CEA Building Systems & Energy Efficiency 3

Question 1

A boiler operates at 78% thermal efficiency. If the boiler input is 1,000 MBH, what is the useful heat output?

Accepted Answer

780 MBH

Answer

Useful output = input × efficiency = 1,000 MBH × 0.78 = 780 MBH; the remaining 220 MBH is lost through flue gases and jacket losses.

Question 2

What does ASHRAE 90.1 primarily regulate for commercial buildings?

Accepted Answer

Energy efficiency design requirements for building envelope, HVAC, lighting, and service water heating

Answer

ASHRAE 90.1 is the Energy Standard for Buildings Except Low-Rise Residential Buildings, setting minimum efficiency requirements for envelope, HVAC, lighting, and SWH systems.

Question 3

Which control strategy directly reduces plug load energy consumption in an office?

Accepted Answer

Occupancy-based power strip switching

Answer

Occupancy-based smart power strips cut power to workstation peripherals when a workstation is unoccupied, directly targeting plug and process loads.

Question 4

In a heat recovery ventilation (HRV) system, what is the function of the heat exchanger core?

Accepted Answer

Transfer heat between exhaust and supply air streams without mixing them

Answer

The HRV core transfers sensible heat (and in ERV systems, moisture) from the warmer exhaust stream to the cooler supply stream, recovering energy that would otherwise be wasted.

Question 5

What is the 'stack effect' in tall buildings and how does it affect energy use?

Accepted Answer

Warm air rises creating pressure differentials that drive infiltration and increase heating/cooling loads

Answer

Stack effect creates a buoyancy-driven pressure difference that forces warm air out at upper floors and draws cold outdoor air in at lower floors, significantly increasing heating energy in winter.

(CEA) Certified Energy Analyst Practice Test

(CEA) Certified Energy Analyst Practice Test

CEA Building Systems & Energy Efficiency 3