HVAC Building Automation Systems 5

Question 1

What is the purpose of a BAS 'global controller' or 'central plant optimizer'?

Accepted Answer

Coordinate chiller, boiler, and cooling tower sequencing to minimize total plant energy

Answer

A central plant optimizer coordinates multiple pieces of equipment to minimize total energy consumption while meeting load requirements.

Question 2

A BAS trend log shows supply air temperature consistently 3°F above setpoint. After confirming the setpoint is correct, what is the most likely issue?

Accepted Answer

Sensor offset or calibration error

Answer

A consistent offset between setpoint and measured value typically indicates a sensor calibration error or transmitter offset rather than a control logic problem.

Question 3

What does 'load shedding' mean in a BAS demand-limiting strategy?

Accepted Answer

Temporarily reducing HVAC loads to prevent exceeding a peak demand threshold

Answer

Load shedding strategically reduces non-critical HVAC loads when electrical demand approaches a utility-defined threshold to avoid demand charges.

Question 4

In BAS terminology, what is a 'soft point' or 'virtual point'?

Accepted Answer

A calculated or logical data point that exists only in software, not tied to a physical input or output

Answer

Virtual or soft points are software-calculated values derived from physical points, such as average zone temperature or total airflow.

Question 5

Which standard governs cybersecurity requirements for building automation and control network systems?

Accepted Answer

NIST SP 800-82 and ASHRAE Guideline 13

Answer

NIST SP 800-82 and ASHRAE Guideline 13 address cybersecurity best practices for industrial and building control network systems.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC Building Automation Systems 5