Exam 1 - HVAC

Question 1

What is the instrument that measures sound?

Answer 1

Decibel Meter

Question 2

In order to produce a signal and be heard, a sound must be ____ dB above the current sound power level.

Answer 2

10 dB

Question 3

“The solution to pollution is ____.”

Answer 3

Dilution

Question 4

Odors are usually treated by adding _____ _____ into a space.

Answer 4

Outside Air

Question 5

The most difficult odor to remove from HVAC systems is _______.

Answer 5

Tobacco Smoke

Question 6

“____________” is a result of shutting down ventilation and preventing fresh outside air from entering a space.

Answer 6

Sick Building Sydnrome

Question 7

VOC stands for _____.

Answer 7

Volatile Organic Compounds

Question 8

Sick Building Syndrome affects occupants in which ways?

Answer 8

Occupants experience headaches, nausea, or respiratory problems attributed to stressful factors in the working environment.

Question 9

Most people will report that they are comfortable in an interior building space with __ - ___ degree air temp, at a relative humidity of about ____%.

Answer 9

• 68 to 75 degrees Fahrenheit

- 50%

Question 10

About how many times does “peak design load” occur in an HVAC system per year?

Answer 10

1 time. The rest of the year is at part-load, or “shoulder load”.

Question 11

What is the “Comfort Region”, in regards to psychometrics?

Answer 11

The Comfort Region is the transparent area on a psychometric chart which illustrates what the average person would consider “comfortable”. This can be taken to court to save your ass!

Question 12

Define IAQ

Answer 12

Indoor Air Quality relates to the air experienced by the occupants of the building.

Question 13

Required CFM for a smoking room.

Answer 13

60 CFM

Question 14

This standard sets the minimum requirements for HVAC filter systems.

Answer 14

ASHRAE Standard 52

Question 15

Construction sites range from ____ dB to _____ dB

Answer 15

80 dB to 90 dB

Question 16

What are the components of “comfort”?

Answer 16

1. Scents/Odors
2. Temperature/Moisture
3. Air Quality
4. Noise/Sound
5. Light
6. Air Flow/Velocity
7. Activity Level

Question 17

At rest metabolic rate

Answer 17

300 Btu/h or 100 watts per person

Question 18

This component of a cooling system compresses the refrigerant in its gaseous state.

Answer 18

Compressor

Question 19

Condenses refrigerant gas to liquid.

Answer 19

Condenser

Question 20

A device that causes a large pressure drop as the liquid refrigerant flows through it.

Answer 20

Expansion Device

Question 21

Where cooling happens. Converts refrigerant to gas at a much colder temperature and a lower pressure.

Answer 21

Evaporator Coil or Evaporator

Question 22

The maximum (or worst) design conditions.

Answer 22

“At Design”

Question 23

A rule of thumb for calculating the design load for a cooling system.

Answer 23

1.0 cfm/sqft

Question 24

Q = ?
cfm = ?
Delta T = ?

Answer 24

Q = Btu/h
cfm = Cubic Feet Per Minute of Air
Delta T = Temperature difference that is driving the load

Question 25

Estimate the design cooling load for a 60,000 sqft office building. The supplied air is at 55 degrees and the return air is at 80 degrees.

Answer 25

1. Q = 1.1 x cfm x Delta T 2. cfm = 60,000 x 1.0 cfm/sqft = 60,000 cfm 3. Delta T = 80 - 55 = 25 degrees 4. Q = 1.1 x 60,000 x 25 = 1,650,000‬ Btu/hr

Question 26

1 ton of cooling is equal to a cooling rate of _____ Btu/hr

Answer 26

12,000 Btu/hr

Question 27

12,000 BTUh/ton means that a 6 ton unit would have a cooling capacity of ______ BTU.

Answer 27

72,000 BTU

Question 28

Convert 72,000 Btu/hr to Tons

Answer 28

(72,000 Btu/hr) x (1 ton/12,000 Btu/hr) = 6 Tons

Question 29

Rule-of-thumb for cooling load and sqft of space

Answer 29

500 sqft/ton

Question 30

Rule-of-thumb for cooling load and sqft of space for a residential space

Answer 30

1000 sqft/ton (provided that R-30 is in the roof and R-19 is in the walls.

Question 31

At Design Temperatures

Answer 31

Supply Air = 55 degrees | Return Air = 80 degrees

Question 32

Energy transfer through fluid motion, in both gasses and liquids.

Answer 32

Convection | Ex. Heat "waves" shimmering off of hot pavement

Question 33

Energy transfer because of a material's property

Answer 33

Conduction | Ex. Touching a hot iron or stove

Question 34

Energy transfer through electromagnetic waves (Magic lol)

Answer 34

Radiation | Ex. Standing near a campfire

Question 35

The most visible (bright or white) component of an infrared image attributes mostly to the ______ load of the photographed area.

Answer 35

Cooling Load

Question 36

The function of Low-E Glass

Answer 36

Low-E glass does not re-emit the heat it absorbs.

Question 37

This instrument can measure the Wet Bulb Global Temperature.

Answer 37

Heat Stress Meter

Question 38

The higher the WGBT, the more frequently workers should take a rest. True or False?

Answer 38

True, baby boy

Question 39

What causes condensation?

Answer 39

Any surface with a temperature cooler than the dew point of the surrounding air will cause condensation to occur on that surface. Therefore, HVAC systems "dehumidify" an area by operating a heat exchanger surface below the dewpoint of the surrounding air.

Question 40

The movement of energy through the removal of or addition of moisture in the air.

Answer 40

"Latent Heat Transfer"

Question 41

The cooling of the air, with no removal or addition of moisture in the air conditioning process.

Answer 41

"Sensible Cooling" Relative humidity still changes during this process. Ex. Chilled beam system

Question 42

Cooling of the air through the EVAPORATION of water

Answer 42

Evaporative cooling Ex. Humans and their nasty, sticky, sweat. MMMMM so GoOoOOD

Question 43

Why insulate chilled water piping?

Answer 43

To prevent condensation

Question 44

Define enthalpy

Answer 44

Enthalpy is how much energy is in the air. Temperature and moisture are included.

Question 45

This refrigerant replaced R-22

Answer 45

R-410a

Question 46

Typical car refrigerant

Answer 46

R-134a

Question 47

Estimated temperature entering an expansion valve

Answer 47

105 degrees Fahrenheit

Question 48

Estimated temperature leaving an expansion valve

Answer 48

45 degrees Fahrenheit

Question 49

The "killer" of electrical components

Answer 49

Heat

Question 50

SEER

Answer 50

Seasonal Energy Efficient Ration A rating for cooling units

Question 51

Ice on an evaporator coil would be a symptom of ______.

Answer 51

Low refrigerant

Question 52

Wet Bulb Temperature measures _____, whereas Dry Bulb Temperature measures ______.

Answer 52

- Humidity | - Regular temperature

Question 53

The 0th Law of Thermodynamics

Answer 53

"There is no temperature change without the exchange of energy."

Question 54

A WBGT of 82 or greater would not be good for high activity levels. True or false

Answer 54

True

Question 55

The curve on the Psychometric Chart is known as the _________.

Answer 55

Saturation Line

Question 56

Characteristics of Low-E Glass

Answer 56

1. Prevents heat/light transfer | 2. Non-reflective

Question 57

A net-zero building, in theory, would ______.

Answer 57

Use as much energy as it creates

Question 58

There are ____ branch circuits on a line diagram

Answer 58

0

Question 59

A line diagram represents ______.

Answer 59

The distribution on power throughout a building

Question 60

IPD

Answer 60

Integrated Project Delivery

Question 61

This type of contract requires that every party signs, a split contingency between all parties, and a joint sharing of risks and rewards.

Answer 61

IPD

Question 62

Just-In-Time delivery is a characteristic of CPM True or False

Answer 62

False. Just-In-Time delivery is an element of LPS

Question 63

CPM vs LPS

Answer 63

CPM - Detailed planning - High resource utilization - Schedule is forced onto people LPS - Plan incrementally - Daily adjustments - Journey men know duration of activities - Daily Huddles - Trust - JIT Delivery

Question 64

The number of skilled laborers is in a(n) ______.

Answer 64

Decline This affects self-perform the most.

Question 65

The two acronyms addressing methods of labor risk management are _____ and ______.

Answer 65

- TIMMES (Resources) | - DOWNTIME (Waste)

Question 66

An example of modular construction could be _____.

Answer 66

The recently built Chinese hospital. Data centers.