HVAC Building Automation Systems

Question 1

What does the acronym 'BAS' stand for in commercial HVAC?

Accepted Answer

Building Automation System

Answer

Boiler and Air System

Answer

Building Air Scheduling

Answer

Baseline Automated Sensing

Question 2

What communication protocol is most widely used for BAS integration in commercial HVAC?

Accepted Answer

BACnet

Answer

Modbus RTU

Answer

LonWorks

Answer

KNX

Question 3

What is a 'DDC' controller in a building automation system?

Accepted Answer

Direct Digital Control — uses microprocessors to control HVAC equipment based on sensor inputs

Answer

Digital Data Compiler — stores sensor readings

Answer

Dynamic Damper Controller — controls VAV box dampers only

Answer

Dual Duct Controller — manages dual duct HVAC systems

Question 4

What is the purpose of a Variable Air Volume (VAV) box in a BAS-controlled system?

Accepted Answer

To modulate airflow to individual zones to maintain zone temperature setpoints

Answer

To vary the speed of the supply air fan based on building occupancy

Answer

To vary refrigerant flow to the air handling unit coil

Answer

To control outdoor air intake based on CO2 levels

Question 5

What is 'demand-controlled ventilation' (DCV) and what sensor drives it?

Accepted Answer

Outdoor air ventilation modulated based on actual occupancy, driven by CO2 sensors

Answer

Ventilation controlled by occupancy schedules using time clocks

Answer

Variable speed fans controlled by supply air pressure sensors

Answer

Exhaust air fans controlled by humidity sensors

Question 6

What does 'PID control' stand for and what are its three components in a BAS?

Accepted Answer

Proportional-Integral-Derivative — three terms that eliminate steady-state error and improve control response

Answer

Process Integration and Distribution — distributes control signals to multiple points

Answer

Pressure-Integrated-Damper — a pneumatic control method

Answer

Pre-programmed Integrated Distribution — preset control sequences

Question 7

What is an 'occupied/unoccupied' setback schedule in a BAS?

Accepted Answer

Temperature setpoint schedules that relax HVAC control setpoints during unoccupied periods to save energy

Answer

A schedule that increases maintenance frequency during occupied hours

Answer

A fire alarm schedule that tests smoke detectors during unoccupied hours

Answer

A schedule that increases outdoor air during occupied hours

Question 8

What is the primary function of an 'economizer' controlled by a BAS?

Accepted Answer

To use outdoor air for free cooling when outdoor conditions are favorable, reducing mechanical cooling

Answer

To recover heat from exhaust air to pre-heat incoming outdoor air

Answer

To reduce the size of the refrigeration equipment needed

Answer

To control the amount of refrigerant used during peak demand

Question 9

What is the difference between a 'hardwired' point and a 'network' point in a BAS?

Accepted Answer

Hardwired points are physically wired to the controller; network points communicate via a digital network protocol

Answer

Hardwired points are analog; network points are digital

Answer

Hardwired points are permanent; network points can be added remotely

Answer

Hardwired points control equipment; network points only monitor

Question 10

What does 'ASHRAE 90.1' establish that BAS designers must follow?

Accepted Answer

Energy efficiency standards including HVAC controls requirements for commercial buildings

Answer

Minimum refrigerant safety standards

Answer

Indoor air quality ventilation minimums

Answer

Refrigerant recovery procedures