Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Term 3 - Load Calculations > Power point > Flashcards

Power point Flashcards

(82 cards)

Start Studying
1
Q

What are some cons of installing larger equipment?

A
  1. Cost more
  2. Requires large air distr.
  3. short cycling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Oversized air conditioning equipment will cool faster which decreases the ______________ effect

A

dehumidification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Undersized heating/cooling systems will not be able to ____________ set-point

A

maintain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

True or False?

It is more beneficial to have your Heat/AC run all day vs periodically in extreme conditions. Why?

A

True. It will never catch up if extreme set-points are desired in extreme conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is required in order to qualify for many government rebates?

A

Heat gain/loss calculation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Heat flows from hot to cold until?

A

temperatures are equalized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In warmer months, heat leaks ____ the structure

A

in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In colder months, heat leaks ____ the structure

A

out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Rule of thumb load estimate is the first type of load estimate that occurs up front in the design process

it includes

A

sqft
btuh
cfm
gpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Temperature differential is the difference between the _______ and ______ of the building

A

inside and outside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

As the TD increases the _________ _____ increases and rise versa

A

transfer rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name three environment effects on a building envelope

A
  1. solar gains (transfer gain tg.)
  2. humidity grains
  3. wind (infiltration gain ig)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

True or False?

Daily range is the TD from morning to night

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the typical design indoor temperature in heating season?

A

70F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Typical indoor design temperature in cooling season?

A

75F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Name 4 heat loads for heating

A
  1. heat escaping through cracks
  2. poor insulation
  3. heat transferring to colder areas
  4. exposure to wind forcing cold air in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Name 4 heat loads for cooling

A
  1. sun through windows
  2. cracks and openings
  3. sun exposure on outside of building
  4. heat from appliances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the R value used for?

A

rate the thermal resistance of insulation materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The higher the R value, the _______ it is for heat to pass through the material

A

harder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

If the wall is made up of different materials, how is the R value calculated?

A

The R value of each material used is added for a total R

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Heat ________ is the heat conducted through walls, ceilings, and floors when. temperature difference is present

A

leakage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

The amount of heat that will pass through 1ftsq of material 1’’ thick in 1 hour when the temperature difference is 1F is known as ?

A

Thermal conductivity (K value)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

High __ values indicate high rate of heat transfer

A

K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Amount of heat that will pass through 1ftsq of material that is NOT 1’’ thick in 1 hour when the temperature difference is 1F is known as?

A

C-value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the difference between C and K values?
K value is based on material that IS 1'' thick. C value is based on material that is NOT 1'' thick
26
How to determine thermal conductance?
Find on chart and divide K value of each material by its thickness
27
What is Thermal Resistance (R value)
Resistance to heat transfer
28
Higher R value indicates ________ heat transfer
slower
29
What are some examples of composite building materials?
wood, drywall, siding
30
Formula for calculating homogenous materials R value?
R = 1/C (using c factor)
31
Formula for calculating composite building materials R value?
RT = R1 + R2 + R3
32
What is Thermal transmittance? (U value)
Similar to C-value but includes adjustment for boundary air films
33
Thermal Transmittance (U value) Formula U = 1/Rof +R1 + R2 + R3 + Rif What does Rof and Rif mean?
Thermal resistance of outside air film and inside air film
34
The U-value describes the thermal _________ of a material
conductivity
35
The higher the U value, the _______ it is for heat to pass through a material
easier
36
Use construction materials with high __ values and low __ values
high r values low u values
37
R and U values are _______ of each other
inverse U= 1/R
38
Summertime indoor design temperature and humidity?
75F (24C) @50% relative humidity
39
The rate of heat transfer through a wall is this formula: Describe each variable
Q=U-value x TD x Area Q = heat in btuh U-value = U-value of the wall TD = TD across the wall Area = Area of the wall
40
Do partition walls require a separate heat loss calculation?
yes
41
_________ and ________ are calculated separately in wall heat loss calculations
windows and doors
42
What is the net wall area?
combined area of windows and doors
43
How to calculate total wall area?
perimeter x ceiling height
44
Where to find heat transfer factor (U)
from tables
45
How to calculate Transmission gain and loss through a wall?
Q= U value x TD x area
46
Heat loss through __________ walls account for a large percentage of total heat loss of a structure
exposed walls
47
It is important to know what lumber was framed with and the __ value of the insulation
R value
48
Describe heat lag
time it takes for heat to travel through a substance heated on one side
49
Normal buildings have _ to _ hours of heat lag
3 to 4 hours
50
Well insulated buildings or thick walls have what benefits?
Transfer heat into room during the night Provide warmth after temperature drops
51
Calculate the heat transfer rate using k-values
R = 1/K x thickness
52
Calculate the heat transfer rate using C -values
Rt= 1/c1 + 1/c2 + 1/c3
53
U is the inverse of R so the formula is?
1/Rt
54
Difference between gross and net wall area?
gross is before doors or windows net is after
55
How to calculate heat loss through windows and doors?
Same method as walls
56
How to calculate heat loss through roofs?
Same method as walls but calculating with geometry
57
What is a partition wall?
Separates conditioned interior space from an unconditioned interior space
58
TD through partition walls?
Indoor design temperature and temperature of unconditioned space
59
The rate of heat loss ______ as the floor gets deeper?
decreases
60
Heat loss through floors located above unconditioned spaces is calculated the same as?
partition walls
61
Heat loss through slab floors is calculated using the ________ ft of the exposed slab edge not the area of the floor
running feet
62
Heat loss through cracks, openings, and deficiencies in structure calculated by;
Q-infiltration = 1.08 x cfm x TD 1.08 = constant com = cubic feet of air entering TD = design temp diff
63
Duct losses to unconditioned spaces such as attics, ceiling spaces, etc is when?
heat is lost passing through an unconditioned space
64
What is one of the major sources for heat gain?
windows
65
When calculating heat gain (cooling mode) take into account; (4)
1. envelope contact w outside 2. occupancy 3. heat/moisture generating elements 4. orientation of house
66
Heat gain through exposed exterior walls/Doors is calculated by;
Qwall= U value x TDcool x Area Qdoor = U value x TD cool x Area Qwall = heat attributed to wall U value = u value of door TDcool= two part chart needed Area = area of the wall
67
Triple glazed glass has a ____ R value and ____ U value
high r low u
68
Name 4 types of windows
1. Casement 2. Double Hung 3. FIxed 4. Sliding
69
Infiltration is best described as;
air pressure inside is lower than outside due to air leaking in
70
Exfiltration is best described as;
air pressure inside is higher than outside due to air leaking out
71
What environmental element causes infiltration and exfiltration?
wind
72
Common rule of thumb for building pressure is
supply exceeds return + exhaust by 10%
73
Negative pressure is calculated by adding return air cfm and
direct exhaust air cfm
74
Balanced pressure means air in =
supply air cfm
75
Are internal loads calculated when sizing heat capacity?
NO
76
Greatest need for heat is during _________ hours
unoccupied hours
77
Warm-up ______ ________ reserve capacity is recommended if set-point setback is used during unoccupied times
safety factor
78
Heat is transferred from the body by; (4)
1. Conduction 2. Convection 3. Radiation 4. Evaporation
79
Calculate fluorescent lighting heat gain to space and to return air plenum
space = watts x 4.1btuh/watt x 0.60 ra= watts x 4.1btuh/watt x 0.40
80
In a low pressure system, how much static is there and how much cfm is lost?
under 2'' static and 5% cfm lost
81
In a mid pressure system, how much static is there and how much com is lost?
2-6'' static and 2% to 5% cfm is lost
82
In a high pressure system, how much static is there and how much com is lost?
over 6'' static and 1% cfm lost

Term 3 - Load Calculations (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions