Top Banner
Heat Loss & Gain Calculations 1
84

Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Dec 19, 2015

Download

Documents

Loraine Garrison
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Heat Loss & Gain Calculations

1

Page 2: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

How Heat Moves in HomesConduction is the transfer of heat through solid

objects, such as the ceilings, walls, and floors of a home. Insulation (and multiple layers of glass in windows) reduces conduction losses. The direction of heat flow is from hot to cold, so this illustration shows conduction from a warm interior to a cooler outdoors.

2

Page 3: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

3

Page 4: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

As Temperature Differences Increase,Heat Loss Increases

4

Page 5: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

Resistance

5

Page 6: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

As Resistance Increases, Heat Loss Decreases

6

Page 7: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

7

Conduction Heat Loss

Page 8: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

How Heat Moves in HomesConvection is the flow of heat by currents of air.

Air currents are caused by pressure differences, stirring fans, and air density changes as it heats and cools. As air becomes heated, it becomes less dense and rises; as air cools, it becomes more dense and sinks.

8

Page 9: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

9

Convective Heat Loss

Page 10: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Convective Heat Loss - Air Leakage

HighPressure

LowPressure

10

Page 11: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Convective Heat Loss - Air Leakage

HighPressure

LowPressure

As Pressure Differences Increase,Heat Loss Increases

11

Page 12: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HighPressure

LowPressure

As Leakage Area Decreases,Heat Loss Decreases

12

Convective Heat Loss - Air Leakage

Page 13: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Natural

HighPressure

LowPressure

13

WindwardSide of House

Page 14: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Natural

HighPressure

LowPressure

14

LeewardSide of House

Page 15: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Mechanical

HighPressure

LowPressure

15

Tight Supply Duct &

No Return Duct

Page 16: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Mechanical

HighPressure

LowPressure

16

Tight Supply Duct &

Return Duct Leaks

Page 17: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Mechanical

HighPressure

LowPressure

17

Supply Duct Leaks &

Tight Return Ducts

Page 18: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Stack Effect

HigherPressure

LowerPressure

Hot Air

Rises

18

Page 19: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Stack Effect

HigherPressure

LowerPressure

Hot Air

Rises

19

Effectedby

Heightand

TemperatureGradient

Page 20: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

What Causes Pressure? Stack Effect

HigherPressure

LowerPressure

Hot Air

Rises

20

Neutral Pressure

Plane

Page 21: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

How Heat Moves in Homes

Radiation is the movement of energy in waves from warm to cooler objects across empty spaces, such as radiant heat traveling from the inner panes of glass to outer panes in double-glazed windows in winter.

21

Page 22: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Equations - Conduction

q = A * T R

– where• q = heat flow, Btu/hr• A = area, ft2

• R = resistance, ft2-hr-°F/Btu• T = temperature differential, °F

Higher temperature – Lower temperature

22

Page 23: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Where Do You Get R?

• Table of R-values for various materials• Some values are for entire thickness

– Brick– Plywood– Gypsum Board

• Some values are per inch of thickness– Wood (framing)– Insulation

23

Page 24: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

How do R-values Add?

24

RT = R1 + R2 + R3

R1 R2 R3

Page 25: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

How do R-values Add? - Example

25

RT for a Structurally Insulated Panel (SIP)

½ inch plywood = 1.254 inch Rigid Foam Center = 4 per inch = 16.00

½ inch plywood = 1.25 RT = 18.50

Page 26: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Equations - Conduction

q = U * A * T– where

• q = heat flow, Btu/hr• A = area, ft2

• U = conductance, Btu/ft2-hr-°F• T = temperature differential, °F

26

Page 27: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

• Where does U come from?– Table values

• How do they add? 1 = 1 + 1

UT U1 U2 • Commonly provided for the entire assembly

27

Equations - Conduction

Page 28: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

U-factor

A U-factor is used to describe an area that is composed of several materials.

Example:Window U-factor includes the glass, frame, and sash.

28

Page 29: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Relationship Between R and Uq = U * A * T

q = A* TR

U * A * T = A * T R

U * A * T = A * T R

U = 1 R

29

Page 30: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Air Leakage - General Equation

q = m * Cp * T– where

• q = heat flow, Btu/hr• m = mass flow of air, lbs/hr• Cp = specific heat of air, 0.24 Btu/lbs -°F• T = temperature differential, °F

30

Page 31: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Air Leakage - General Equation

q = m * Cp * T– where does m come from?

m = mass flow of air, lbs/hr

Under normal conditions in a home: Density of Air = 13.5 ft3 per lb air Cubic Feet of Air = m 13.5

31

Page 32: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Air Leakage For Ducts

q = 1.08 * cfm * T (ducts)– where

• cfm = duct leakage rate to the outside

– where does the 1.08 come from?cfm * 0.24 * 60 min/hr = cfm * 1.08 13.5 ft³/lb air

32

Page 33: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Air Leakage for an Entire House• q = 0.018* ft³/hr * T

– where• ft³/hr = air leakage rate for the entire house• Where does the 0.018 come from?

ft³/hr * 0.24 = ft³/hr * 0.018 13.5 ft³/lb air

• ft3/hr = ACHnat * Volume (ft3)– where

• ACHnat = Natural Air Changes per hour• Volume = volume of the conditioned space

• q = 0.018* ACHnat * Volume (ft3) * T

33

Page 34: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, Calculation

Assume 10x10 wall A = 100 ft2

Cavity Insulation R value = 13T = 1 degree

q = 100 * 1 = 7.69 Btuh 13What is missing?

34

Page 35: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, Calculation

What about the wood framing?

2x4 R-value = 4.38 (1.25 per inch)

35

Page 36: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, Calculation

Typical Wood Framing

36

Page 37: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Minimum Wood FramingApproximately 10 2x4s, 10 ft longEach stud:

1.5 inches wide10 ft * 12 inches/ft = 120 inches long

10 studs * 1.5 in * 120 in = 1800 square inches

1800 in2 / 144 in2 per ft2 = 12.5 ft2

Simple Heat Flow, q, Calculation

37

Page 38: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, Calculation w/Framing

Total Area = 100 ft2 10x10 wallCavity Insulation R-value = 13Framing R = 4.38Framing Area = 12.5 ft2

Cavity Insulation Area = 100 – 12.5 = 87.5 ft2

T = 1 degree

38

Page 39: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

qinsulation = 87.5 * 1 = 6.73 Btuh 13

qframing = 12.5 * 1 = 2.85 Btuh 4.38

qtotal = qinsulation + qframing = 6.73 + 2.85 = 9.58 Btuh

39

Simple Heat Flow, q, Calculation w/Framing

Page 40: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Calculating R when q is Known

40

Page 41: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Calculating R when q is Known

41

Page 42: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

R-Value of the Entire Wall w/Framing

qtotal = 9.58 Btuh/°F

R = A * T = 100 * 1 = 10.44 q 9.58

TOTAL WALL R

42

Page 43: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Another Equation to Calculate Total Wall R

RT = _______AT________ _A1_ + _A2_ R1 R2

43

R-Value of the Entire Wall w/Framing

Page 44: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, Calculation

What if there is a window in the wall?

Window:Size 3 ft x 5 ft = 15 ft2 U-factor = 0.40

44

Page 45: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Framing + Window

45

Page 46: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, CalculationWith Framing + Window

Windows Require Extra Framing Materials

4 extra studs for kings and jacks2x12 36 inch long for the header

Approximately 7.8 ft2 of extra framing

Total framing = 12.5 + 7.8 = 20.3 ft2

46

Page 47: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, CalculationWith Framing + Window

Total Area = 100 ft2 10x10 wallCavity Insulation R-value = 13Framing R-value = 4.38Framing Area = 20.3 ft2

Window U-factor = 0.40Window Area = 15 ft2 Cavity Insulation Area = 100 – 20.3 - 15 = 64.7 ft2

T = 1 degree

47

Page 48: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Simple Heat Flow, q, CalculationWith Framing + Window

qinsulation = 64.7 * 1 = 4.98 Btuh 13qframing = 20.3 * 1 = 4.63 Btuh 4.38qwindow = 0.40 *15 * 1 = 6 Btuh

qtotal = 4.98 + 4.63 + 6 = 15.61 Btuh

48

Page 49: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

R-Value of the WallWith Framing + Window

qtotal = 15.61 Btuh/°F

q = A * T R R = A * T = 100 * 1 = 6.41

q 15.61

49

Page 50: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

R-Value Comparison

Cavity Insulation OnlyR = 13

Cavity Insulation + FramingR = 10.44

Cavity Insulation + Framing + WindowR = 6.41

50

Page 51: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Your Turn

Total Area = 1000 ft²

CeilingR = 38

Pull Down StairsArea = 15 ft²R = 2

What is the R value of the total ceiling?

51

Page 52: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Your TurnCeiling

q = (1000 – 15) = 25.9238

Pull Down Stairs q = 15 = 7.5 2Total q = 25.92 + 7.5 = 33.42

R = _1000_ = 29.92 33.42

52

Page 53: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HERS Rating Software Examples

Must know:• Areas• R / U values• Temperature Differential

– Indirectly by knowing what is on the other side of the surface

53

Page 54: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

54

Above Grade Wall Properties

Page 55: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

55

Page 56: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

56

Page 57: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

Typical Resistances in a Wall

Outside Air Film

Exterior Finish

Cavity Insulation

Gypsum Board

Inside Air Film

57

Page 58: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

58

Page 59: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

59

Exterior Finish

Page 60: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

R of Cavity Wall Section

Inside Air = 0.685/8” Gypsum Board = 0.56

3 ½” Cavity Insulation = 13.00Exterior Finish= 0.94

Outside Air = 0.17Cavity Wall Section R = 15.35

60

Page 61: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Conduction Heat Loss

HighTemperature

LowTemperature

Typical Resistances in a Wall

Outside Air Film

Exterior FinishFraming

Gypsum Board

Inside Air Film

61

Page 62: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

R of Framing Wall Section

Inside Air = 0.685/8” Gypsum Board = 0.56

3 ½” Framing = 4.37Exterior Finish = 0.94

Outside Air = 0.17Framing Wall Section R = 6.72

62

Page 63: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

63

Framing Factor

Page 64: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

64

Framing Factor

Page 65: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Your Turn - Total Wall R

Cavity Wall Section R = 15.35Framing Wall Section R = 6.72Framing Factor = 0.23 (23% of the wall is framing)

Remember - the objective is to calculate “q” correctly

65

Page 66: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Total Wall U

Total Wall R = 11.85

Total Wall U = 1 = 1 = 0.0843 R 11.85

68

Page 67: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

69

Total Wall U

Page 68: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

Total UA for a House

2006 IECC Compliance (2006 IRC, Chapter 11, Energy Efficiency)

• Prescriptive• Overall Building UA• Annual Energy Cost

70

Page 69: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

71

REM/Rate Overall Building UA

Page 70: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

72

REM/Rate Annual Energy Cost

Page 71: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

• Heating– What is T?

• Winter Design Temperature• Lexington = 6°F • Inside Temperature? Typical 68°F

– T = 68 – 6 = 62°F

73

Page 72: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

Heating• Losses (q’s)

– Shell (UA for House)– Infiltration (ACHnat)– Duct Loss (cfm)

• Gains– ?? (People are not considered)

74

Page 73: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

• Cooling– What is T?

• Summer Design Temperature• Lexington = 91°F • Inside Temperature? Typical 76°F

– T = 91 – 76 = 15°F

75

Page 74: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

Cooling• Gains (q’s) - Complex

– Shell (UA for House)– Infiltration (ACHnat)

• Adds Moisture

– Duct Gain– Solar (Radiation - Windows)– People

76

• Losses– ??

Page 75: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

Is T the same for all surfaces?

77

Page 76: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Design Peak Loads

Is T the same for all surfaces?

Basement Walls to the GroundCeiling to the AtticWall to the GarageFloor to the Crawl Space

78

Page 77: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

79

REM/Rate Peak Component Loads

0.57 ACHn

15% Duct Loss to Outside

Page 78: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Annual Loads• Heating

– What is an annual T?• Heating Degree Days

65°F - Average daily temperature Add them for one year

• Lexington = 4683 HDD

• q = U * A * T T = Heating Degree Days * 24

• Close but More Complex

80

Page 79: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Annual Loads• Cooling

– What is an annual T?• Cooling Degree Days

Average daily temperature – 65°FAdd them for one year

• Lexington = 1175 CDD

• More Complex Calculation– Solar Radiation– Dehumidification

81

Page 80: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

82

REM/Rate Annual Component Loads

Page 81: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Annual Consumption• Heating Equipment Efficiency

– Heat Pump • Heating Season Performance Factor (HSPF)

– Btu/Watt-hr

– Geothermal Heat Pump• Coefficient of Performance (COP)

– Watt-hr output / Watt-hr input

– Gas (Combustion)• Annual Fuel Utilization Efficiency (AFUE)

– Btu output / Btu input

83

Page 82: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Annual Consumption

• Cooling Equipment Efficiency– Heat Pump / Air Conditioner

• Seasonal Energy Efficiency Ratio (SEER)– Btuh/Watt

– Geothermal Heat Pump• Energy Efficiency Ratio (EER)

– Btuh/Watt

84

Page 83: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

HVAC Annual Consumption

Equipment Efficiency Adjustment in REM/RateFormula Created by Florida Solar Center• Cooling

– Reduced for Hotter Climates• Lexington: Label SEER = 13, Reduced SEER = 12.2

• Heating – Heat Pump– Reduced for Cooler Climates

• Lexington: Label HSPF = 7.7, Reduced HSPF = 5.7

85

Page 84: Heat Loss & Gain Calculations 1. How Heat Moves in Homes Conduction is the transfer of heat through solid objects, such as the ceilings, walls, and floors.

86

REM/Rate Annual Component Consumption


Related Documents
Computer Controlled Heat Conduction Unit, with · PDF fileComputer Controlled Heat Conduction Unit, ... and radial conduction can be studied using the Computer Controlled Heat Conduction

Computer Controlled Heat Conduction Unit, with · PDF...

Category: Documents
Heat Conduction Unsteady stateeng.sut.ac.th/.../file/05-Conduction_1482710711.pdfUnsteady state of Heat Conduction Two and three dimensional unsteady state heat conduction Long rectangular

Heat Conduction Unsteady...

Category: Documents
.. Fourier's Heat Conduction ···' ' ? 0 Equation: History ...112577/datastream... · Fourier's Heat Conduction Equation: ... Fourier's Heat Conduction Equation: History, Influence,

.. Fourier's Heat Conduction ···' ' ? 0 Equation: History...

Category: Documents
Radial heat conduction

Radial heat conduction

Category: Engineering
H EAT CONDUCTION · 2017. 9. 21. · Chapter 1 HEAT-CONDUCTION FUNDAMENTALS 1-1 The Heat Flux, 1 1-2 The Differential Equation of Heat Conduction, 4 1-3 Heat-Conduction Equation in

H EAT CONDUCTION · 2017. 9. 21. · Chapter 1...

Category: Documents
Chapter 18 – Transient heat conduction · Transient heat conduction in large ... in semi-infinite solids Transient heat conduction in multi ... and heat transfer in one dimensional

Chapter 18 – Transient heat conduction · Transient heat....

Category: Documents
Chapter 2: Heat Conduction Equation - · PDF fileHeat Transfer Chapter 2: Heat Conduction Equation Y.C. Shih September 2013 2-2 Heat Conduction Equation (4) General Heat Conduction

Chapter 2: Heat Conduction Equation - · PDF fileHeat...

Category: Documents
Heat Transfer Conduction

Heat Transfer Conduction

Category: Documents
Heat Conduction - GBV

Heat Conduction - GBV

Category: Documents
Index by heat conduction number system for three … · Index by heat conduction number system for three ... Jaeger, Conduction of Heat in Solids ... B. Litkouhi, Heat Conduction

Index by heat conduction number system for three … ·...

Category: Documents
Conduction Heat Transfer

Conduction Heat Transfer

Category: Documents
Linear heat conduction

Linear heat conduction

Category: Engineering