ASHRAE Building Energy Efficiency and Sustainability 2

Question 1

Which ASHRAE standard defines the procedures for Level 1, Level 2, and Level 3 commercial building energy audits?

Accepted Answer

ASHRAE Standard 211

Answer

Standard 211 sets the requirements for commercial building energy audits at Levels 1, 2, and 3.

Question 2

A centrifugal supply fan on a VFD drops to 50% speed. Using the fan affinity laws, about how much of its full-speed power does it draw?

Accepted Answer

12.5%

Answer

Fan power varies with the cube of speed, so (0.5)^3 = 0.125, or about 12.5% of full power.

Question 3

In the ASHRAE 90.1 Appendix G Performance Rating Method, which metric is compared against a target to show compliance?

Accepted Answer

Performance Cost Index (PCI)

Answer

Appendix G compliance compares the proposed design's Performance Cost Index with the required PCI target.

Question 4

What is the main difference between an energy recovery ventilator (ERV) and a heat recovery ventilator (HRV)?

Accepted Answer

An ERV transfers both sensible and latent energy, while an HRV transfers mainly sensible heat

Answer

ERV cores such as enthalpy wheels move moisture as well as heat, while HRVs recover mostly sensible heat.

Question 5

Under the ASHRAE 90.1 prescriptive envelope path, what is the maximum vertical fenestration area as a percentage of gross above-grade wall area?

Accepted Answer

40%

Answer

The prescriptive path limits vertical fenestration to 40% of gross above-grade wall area, and designs with more glazing must use a performance path.

ASHRAE - American Society of Heating, Refrigeration and Air Conditioning Engineers Certification Practice Test