HVAC System Design 2

Question 1

What is the primary purpose of a Manual J calculation in HVAC system design?

Accepted Answer

Calculate heating and cooling loads for a building

Answer

Manual J is the ACCA standard method for calculating residential heating and cooling loads to properly size HVAC equipment.

Question 2

In a forced-air system, what is the recommended maximum air velocity in main supply ducts to minimize noise?

Accepted Answer

700–900 FPM

Answer

Main supply ducts are typically designed for 700–900 FPM to balance noise control with efficient air delivery.

Question 3

Which HVAC system configuration uses a single outdoor unit connected to multiple indoor fan-coil units?

Accepted Answer

Variable refrigerant flow (VRF) system

Answer

VRF systems use one outdoor condensing unit connected via refrigerant piping to multiple indoor fan-coil units for zone-level control.

Question 4

What does ACCA Manual D govern in HVAC system design?

Accepted Answer

Residential duct design

Answer

Manual D is the ACCA standard for designing residential duct systems, covering duct sizing, layout, and airflow distribution.

Question 5

A building has a sensible heat ratio (SHR) of 0.70. This means:

Accepted Answer

70% of the cooling load is sensible heat

Answer

SHR is the ratio of sensible cooling load to total cooling load, so an SHR of 0.70 means 70% of the load is sensible.

HVAC Practice Test