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Sheet Metal 3rd Yr > Heat Loss and Heat Gain > Flashcards

Heat Loss and Heat Gain Flashcards

1
Q

When doing Heat Loss calculation, define : Gross Exposed Walls.

A

Gross Exposed Wall is the full lenght of the wall by the full height, includes all penetrations.

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2
Q

Which way does heat travel?

  1. up
  2. down
  3. cold to hot
  4. hot to cold
A
  1. hot to cold
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3
Q

Appliances add loads to a building.

TRUE or FALSE

A

TRUE

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4
Q

Which direction does Air Flow move?

A

From Higher pressure > Lower pressure

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5
Q

With Heat Loss and Gain define : Mass Effect

A

Mass Effect is the heat energy gained from the building materials heating up by the sunlight.

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6
Q

What are the 3 types of AIr Tightness concerning buildings?

A
  1. Loose (built earlier than 1960’s)
  2. Average (built late 1960’s to lat 1980’s)
  3. Tight (built late 1980’s to present)
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7
Q

In modern times do we used Rules of Thumb when calculating heat loss and gain?

TRUE or FALSE

A

FALSE

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8
Q

With Outside Winter design, heating equipment is required to maintain what temperatures in a residential building?

A

No Less than

  • 72*F (22*C) in all living spaces
  • 65*F (18*) in unfinished basement
  • 59*F (15*C) in heated crawl spaces
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9
Q

Fresh (outdoor) air losses are a direct loss to the individual room calculations.

TRUE or FALSE

A

FALSE

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10
Q

What are 3 items that must be considered to determine the leakage of a room?

A
  1. Exposure of the site
  2. Number of penetrations
  3. Age of the building (how air tight)
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11
Q

When the Total Heat Loss for a building is completed, what is the PIck-up and Set-back factor to be used?

A

10% increase is required.

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12
Q

If the direction of the house is known, the wall with the most windows shall be calculated for heat gain as if that wall were facing ____ or ____.

A

east or west.

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13
Q

From where are Alberta outdoor design temperaturres taken?

A

The Alberta Building Code January 2.5% column

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14
Q

What must the Heating System of a building be able to maintain when dealing with Appliances in the building?

A

Maitain the correct Indoor Design Temperature whether the appliances are USED or NOT.

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15
Q

What is the relationship between RH (relative humidity) and comfort?

A

Higher RH (relative humidity) makes you feel warmer.

Our bodies rely on evaporation to cool down, higher RH slows down this process.

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16
Q

What 4 factors affect building environments?

A
  1. Building Envelope
  2. Mechanical Systems
  3. Occupants
  4. Appliances
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17
Q

Solar adjustment must be made when the Summer Mean Temperature is greater than what?

A

8*C

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18
Q

Define : Total Resistance

A

Is the total conductive resistance of all materials that construct a wall that divides Outdoor enviroment from Indoor conditions.

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19
Q

What affects the speed of heat transfer?

A

The GREATER the temperature difference, the FASTER the transfer will take place.

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20
Q

Heat loss (load) calculations can be done using what 3 different methods?

A
  1. Calculating the load of the whole building
  2. Calculating the loads or 1 level at a time.
  3. Calculating each room on an individual basis.
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21
Q

Define : Conduction

A

When heat transfers through the direct contact with another object.

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22
Q

List some Design Manuals used in HVAC design.

A
  • ASHRAE handbooks and standards
  • HRAI digest
  • Hydronic Institute manuals
  • SMACNA manuals
  • ACCA manual J
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23
Q

Define : Radiation

A

When energy is transmitted though electomagnetic waves, which transfer heat from a hotter object to a colder object.

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24
Q

Net Wall calculations are completed by what?

A

Length X Width of the wall, MINUS all penetrations

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25
Q

What are the disvantages and advantages of calculating Floor by Floor Loads?

A

Floor to Floor Load calculation IMPROVE on how distribution is between floors.

BUT

Doesn’t tell you Room to Room.

Should be used as a estimate ONLY

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26
Q

Define : Thermal Resistance (R-Value)

A
  • Is the heat flow through an object in a specific amount of time.
  • R-valve = ( hours X sq. ft. X *F) / Btu
  • Higher resistance materials are called Insulators
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27
Q

When doing Heat Loss calculation, define : Below Grade Walls

A

Below Grade Walls are walls that are more than 2 inches below ground level.

28
Q

When wind speed increases around the outside what happens to the amount of undesirable leakage to the building?

A

Wind Speed Increase = Undesirable Leakage Increase

29
Q

Above and Below Grade walls have the same R-Vlaves.

TRUE or FALSE

A

FALSE

30
Q

What does performing correct Heat Loss and Gain calculations ensure?

A

Proper selection of equipment that will provide comfort for the occupant.

31
Q

What is the formula to calculate : Ventilation AIr Heat Loss

A

Btuh = Ventilation cfm X 1.08 X Design Temperature Difference.

32
Q

Radiant heat adds a load to the load of a building.

TRUE or FALSE

A

TRUE

33
Q

What is the default used when calculating heat gains for glass?

A

No shade or drapes are used.

34
Q

With heat losses and gain, what is the purpuse of the Mechanical System?

A

Mechanical System is a force used to maintain the in-balance between indoor and outdoor conditions.

The load is changing constantly pending time of day and season to season.

35
Q

What is the most ACCURATE method of calculate heat loss (load) in a building?

A

Room to Room Load calculations.

36
Q

What is the concern when dealing with the Air Change in a modern building with a tight envelope?

A

The LESS the leakage rate there is a NEED for fresh air and exhausting of stale contamated air INCREASES.

37
Q

The overall performance of a building and it’s systems are affected by what Air-Flow’s?

A
  1. Air Change Rates
  2. Air-Pressures
  3. Ventilation
  4. Exhaust Systems
  5. Flues
  6. Stack Effects
  7. The Wind
38
Q

HTM is a factor used to calculate what?

A

BTUH per square foot

39
Q

How do Occupants change the heat loss and heat gain of a buiding?

A
  1. Controling the Mechanical System
  2. Opening and closing windows and doors
  3. Occupants generate HEAT (approx 250Btuh, 73W per person).
40
Q

Duct passing through un-conditioned spaces must be what?

A

Insulated

41
Q

Solar Radiation will change the :

  1. heat loss calculation
  2. direction of the house
  3. indoor design temperature
  4. outdoor design temperature
A
  1. outdoor design temperature
42
Q

What are the disvantages and advantages of calculating Whole House Loads?

A

Advantages are that it can be done quickly.

Disadvantages is how these loads distribute throughout the building

Whole House Calculations should ONLY be done as an estimate.

43
Q

What are some points about Ventilation Air Losses

A
  • Introduction of ventilation air are System Losses.
  • DO NOT effect losses to individual rooms
  • Their are Direct Losses to the HVAC unit, must be added to the Total Conductive Heat Loss. (ensure proper HVAC unit selection)
44
Q

Which material has a greater R-valve?

  1. Glass Fibre
  2. Double-Glazed Windows
  3. Cement
  4. Sheet Metal
A
  1. Glass Fibre
45
Q

Define : HTM (Heating Transfer Multiplier)

A

Is a factor used to calculate the amount of heat energy transferred per square foot per hour through walls, floors, ceilings, windows and doors.

HTM = Design Temp. Difference / RT (total resistance)

46
Q

Define : Design Temperature Difference

A

Is the difference between the Indoor Design temperature and the Outdoor Design temperature

47
Q

Outdoor design temperatures are the same for all locations.

TRUE or FALSE

A

FALSE

48
Q

What codes must a HVAC designers must be familiar with?

A
  • Alberta Buiding Code makes reference to heating , ventilating and AC in Part 6.

Also these codes must be concidered

  • Fire Protection
  • Occupant Safey
  • Accessibility
  • Housing and Small Building : Part 9
49
Q

Latitude will not affect shade factors on a building

TRUE or FALSE

A

FALSE

50
Q

Define : BUILDING ENVELOPE

A

Is what seperates the interior from the outdoor environments.

Building structures that provide the neccessary barriers are :

  • Exterial Walls
  • Foundations
  • Roofs
  • Ceilings
  • Floors
  • Windows
  • Doors
  • Vapour Barriers
51
Q

How does the Air Movement affect the temperature you feel?

A
  • Volume of air passing you Increases - Cooler you feel.
  • Volume of air passing Decreases - Warming you feel
52
Q

What are he 6 principles of comfort?

A
  1. Temperature
  2. Humdity
  3. Ventilation
  4. Filtration
  5. Circulation
  6. Noise
53
Q

What are 3 factors that effect Effective Temperature?

A
  1. Air Temperature
  2. Relative Humidity
  3. Air Movement
54
Q

When doing Heat Loss calculation, define : Above Grade Walls

A

Above Wall Grade is all walls that are above ground level.

55
Q

What 3 factors are used to find the correct infiltration factor.

A
  1. Site Exposure
  2. Penetrations
  3. Air Tightness
56
Q

What is the HTM (heat transfer multiplier) for a wall having a total resistance of 16.25 and a design temperature difference of 98*F?

A

HTM (heat transfer multiplier) = design temperature difference / total resistance (R-valve)

HTM = 98*F / 16.25

HTM = 6.03

57
Q

Effective Temperature could be defined as :

A

How a person feels at a set temperture.

58
Q

How do we find the valves for winter design in conditons?

A

From the Alberta Building Code, using the chart for “January @ 2.5% values”

The Outdoor Design temperatures for Northern climates will normally be GREATER than those in Southern climates.

59
Q

What is the Solar Adjustment for fully shaded walls and indoors?

A

-11*F

60
Q

Design Temperature Difference is the difference from indoor design temperature from outdoor design temperatures ?

TRUE or FALSE

A

TRUE

61
Q

Define : HEAT

A

HEAT is a form of energy that flows between 2 bodies due to their differences in temperature.

62
Q

What is the indoor temperature for living spaces?

A

72*F (22*C)

63
Q

What Building Envelope is about reducing what types of losses to the outdoor environment?

A
  • Radiative Losses
  • Conductive Losses
  • Convective Losses
64
Q

Define : Convection

A

The current in a liquid or gas that transfers the heat by moving molecules from a warmer area to a cooler area.

65
Q

Gross wall calculations are completed by multiplying what?

A

Lenght X Width of the wall, including all penetrations.

66
Q

An energy efficient home consists of what type of building materials?

A

Materials that have :

  • High R-Valves (high resistances)
  • Good vapour Barriers

That minimize heat loss or gain to the structure.

Sheet Metal 3rd Yr (7 decks)

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