Certified Energy Auditor Certification HVAC Systems and Performance 4

Question 1

What is the typical minimum outdoor air ventilation rate for office spaces per ASHRAE 62.1?

Accepted Answer

5 cfm per person plus 0.06 cfm/ft²

Answer

ASHRAE 62.1 requires 5 cfm/person (Rp) plus 0.06 cfm/ft² (Ra) for general office spaces under the ventilation rate procedure.

Question 2

A cooling tower's approach temperature is defined as what?

Accepted Answer

Difference between leaving water temperature and ambient wet-bulb temperature

Answer

Approach temperature is the difference between the cooling tower's leaving (cold) water temperature and the ambient wet-bulb temperature — a smaller approach indicates better tower performance.

Question 3

What is 'demand-controlled ventilation' (DCV)?

Accepted Answer

Modulating outdoor air intake based on measured occupancy or CO2 levels

Answer

DCV uses CO2 sensors or occupancy data to adjust outdoor airflow rates dynamically, providing required ventilation only when spaces are occupied.

Question 4

An energy auditor measures a chiller's kW/ton as 0.55. A newer model offers 0.48 kW/ton. If annual chiller run-hours are 2,000 and the facility has 400 tons of cooling, what is the annual kWh savings?

Accepted Answer

56,000 kWh

Answer

Savings = (0.55 – 0.48) kW/ton × 400 tons × 2,000 hr = 0.07 × 400 × 2,000 = 56,000 kWh.

Question 5

What is the purpose of a building's static pressure control in a VAV system?

Accepted Answer

Maintain duct static pressure at a setpoint to ensure terminal boxes can deliver required airflow

Answer

Duct static pressure control ensures enough pressure is available at the most remote VAV terminal so it can open and deliver design airflow.

Certified Energy Auditor Certification Practice Test

Certified Energy Auditor Certification Practice Test

Certified Energy Auditor Certification HVAC Systems and Performance 4