Complex Systems

Question 1

Two basic categories of air distribution?

Answer 1

Constant Air Volume (CAV) / Variable Air Volume (VAV)

Question 2

List different CAV systems

Answer 2

1. Unitary/stand alone
2. Single zone
3. Terminal reheat
4. Face and bypass
5. Multi zone
6. Dual duct
7. Under floor air distribution (UFAD)
8. Make up air

Question 3

In a single zone system, where is the air conditioned?

Answer 3

In the air handling unit

Question 4

What controls the preheat coil in terminal reheat?

Answer 4

All heating, cooling, fresh air introduction and filtering is controlled as a function of the AHU

Question 5

What controls the reheat terminal in terminal reheat system?

Answer 5

A zone valve which is controlled by a zone thermostat that modulates the flow of heated water or steam through the reheat coil

Question 6

What is the expected temperature of a cooling/heating terminal?

Answer 6

100-190 for heating and 40-60 for cooling

Question 7

What is the primary consideration for face bypass with a DX coil?

Answer 7

Evaporator capacity control must be used

Question 8

What type of damper blades are used in face bypass for more accurate control?

Answer 8

Opposed blades

Question 9

In a cooling only, face bypass system, what position will the dampers be in if zone temperature is below setpoint?

Answer 9

Closed so that air bypasses the cooling coil

Question 10

What controls the mixing air damper actuator in a multi zone system?

Answer 10

Independent zone thermostats for each zone control independent mixing damper actuators in the AHU

Question 11

What controls hot and cold deck temperatures in a multi zone system?

Answer 11

Function of the AHU

Question 12

Typical hot and cold deck temperatures in a multi zone system?

Answer 12

90 and 55

Question 13

What is bucking?

Answer 13

Inefficient state of heating and cooling at the same time

Question 14

Typical neutral deck summer temperature?

Answer 14

Heats the zones using 75-80 air

Question 15

How many actuators does a CAV dual duct system have?

Answer 15

Single actuator controlling mixing dampers

Question 16

What does UFAD stand for?

Answer 16

Under floor air distribution

Question 17

What temperature does a CAV MUA supply?

Answer 17

Constant volume near room temperature

Question 18

When can you use DFMUA for sleeping applications?

Answer 18

Never

Question 19

What are IFMUA heat exchangers made of?

Answer 19

Stainless steel in series

Question 20

What is the supply air temperature of a VAV system?

Answer 20

AHU provides a variable air volume at a constant 55 supply

Question 21

How do VAV systems control building static pressure?

Answer 21

Return air volume dampers or by maintaining positive building pressure between ventilation air

Question 22

What happens to the bypass air from VAV bypass terminal?

Answer 22

Returns unused supply air to the AHU through the return air system

Question 23

How many dampers does a dual duct VAV mixing terminal have?

Answer 23

Two

Question 24

What are the advantages of a true VAV system?

Answer 24

Energy efficient and good humidity control

Question 25

3 components of a DCV system?

Answer 25

1. BAS systems with baseline schedules
2. Motion sensors
3. CO2 exhaust sensors

Question 26

4 methods to accomplish VAV

Answer 26

1. Modulate the outdoor air volume using a damper
2. Variable speed supply motor
3. variable speed supply motor with modulating profile plate
4. Complex system of outdoor air and return air dampers

Question 27

List the 4 types of systems

Answer 27

1. All air
2. all water
3. Air and water
4. DIrect

Question 28

What basic type of system is a terminal reheat system?

Answer 28

All air