Midterm 1

Question 1

What percentage of our time is spent indoors?

Answer 1

87%

Question 2

Residential and commercial buildings account for __ of total US energy consumption

Answer 2

40%

Question 3

Buildings are the cause of ______ of US greenhouse gas emissions

Answer 3

34%

Question 4

Is energy a rate or quantity?

Answer 4

Quantity

Question 5

What is power?

Answer 5

Rate at which energy is transferred

Question 6

Energy =

Answer 6

Power x time

Question 7

Power =

Answer 7

Energy / time

Question 8

Units of energy

Answer 8

Watt-hr
Btu

Question 9

Units of power

Answer 9

Watts
Btuh

Question 10

When dealing with energy and power, this equation can be used:

Answer 10

Q = MCΔT

Question 11

Electricity converts to:

Answer 11

Mechanical energy
Light
Heat

Question 12

Primary energy

Answer 12

Site energy plus energy consumed during production and transportation

Question 13

Site energy

Answer 13

Energy directly used by consumers

Question 14

What is 1 Btu?

Answer 14

heat required to raise 1lb of water by 1 F

Question 15

What is thermal comfort?

Answer 15

Condition of mind that expresses satisfaction with the thermal environment

Question 16

What influences thermal comfort?

Answer 16

Weather
Ventilation
Clothing
A/C
Level of Exhaustion

Question 17

Two types of heat losses:

Answer 17

Conduction
Convection

Question 18

What are some occupant-related factors that make someone feel “thermally comfortable”?

Answer 18

Clothes
Age
Gender
Energy Levels

Question 19

What are some environmental factors that make someone feel “thermally comfortable” in a building?

Answer 19

Weather
Humidity
Proximity of fans
materials used

Question 20

Moist air is:

Answer 20

Dry air + Water vapor

Question 21

Psychrometry

Answer 21

Study of gas-vapor mixtures

Question 22

What is humidity ratio?

Answer 22

Ratio of water vapor to dry air

Question 23

What is relative humidity?

Answer 23

Ratio of current humidity to when air is fully saturated

Question 24

Humidity ratio (ω) equation:

Answer 24

(M)v / (M)dry air
Mass of water vapor / mass of dry air

Question 25

What is dew point?

Answer 25

Defined temperature at which condensation happens

Question 26

At dew point temperature, relative humidity is:

Answer 26

100%

Question 27

Wet bulb temperature is _______ than dry bulb temperature

Answer 27

Lower

Question 28

Why is WBT lower than DBT?

Answer 28

Evaporating moisture removes heat

Question 29

As relative humidity gets closer to 100%, WBT gets __________ DBT.

Answer 29

closer to

Question 30

Enthalpy equation

Answer 30

Sensible + Latent

Question 31

What is sensible heat?

Answer 31

energy needed to raise the temperature of a substance

Question 32

What is latent heat?

Answer 32

energy needed for phase change

Question 33

What is sensible heat measured through?

Answer 33

DBT

Question 34

What is latent heat measured through?

Answer 34

Humidity ratio

Question 35

What are the units of Q?

Answer 35

Btu

Question 36

Heating load is:

Answer 36

How much heat is lost and needs to be made up

Question 37

Cooling load is:

Answer 37

How much heat is gained and must be removed

Question 38

Heat transfer happens in conduction:

Answer 38

With Physical contact

Question 39

Heat transfer happens in Convection:

Answer 39

With Air flow (can be sensible or latent)

Question 40

Heat transfer happens in Radiation:

Answer 40

With no contact

Question 41

Heating loads critical design conditions:

Answer 41

Coldest weather Night time Low activity Outside Temp.

Question 42

Cooling loads critical design conditions:

Answer 42

Peak temp. and humidity Daytime High activity Outside temp.

Question 43

Heat transfer equation using area, temperature, and resistance:

Answer 43

Q = A x TD / R (Btu / h)

Question 44

Insulation requires __________ conductivity

Answer 44

Low

Question 45

Conductors require __________ conductivity

Answer 45

High

Question 46

R value

Answer 46

Resistance to heat transfer

Question 47

Heating load is expressed as:

Answer 47

Qsensible

Question 48

Humidification load is expressed as:

Answer 48

Qlatent

Question 49

When calculating heating loads (heat lost, wintertime), use (TD or TETD):

Answer 49

TD

Question 50

When calculating cooling loads (heat gained, summertime), use (TD or TETD):

Answer 50

TETD

Question 51

When calculating heating loads (heat lost, wintertime), should you include latent loads?

Answer 51

No

Question 52

When calculating cooling loads (heat gained, summertime), should you include latent loads?

Answer 52

Yes

Question 53

Heat constant for people:

Answer 53

250 Btu / h