1. code building sciencekenergy.us/files/8613/6787/1652/1.__code_building_science.pdfannual cost of...
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2009$%$2012$Interna-onal$Energy$Conserva-on$Code$
Code$Basic$Energy$Transfer$$Principles!
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Find$This$Presenta-on$$hCp://www.kenergy.us/code%page$$$It$will$be$posted$under$Ohio$
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Learning$Objec-ves$$1. List$the$three$methods$of$heat$transfer.$2. Iden-fy$a$code$requirement$that$addresses$
convec-on.$3. Iden-fy$a$code$requirement$that$addresses$
conduc-on.$4. Iden-fy$a$code$requirement$that$addresses$
radia-on.$5. Iden-fy$3$forces$of$convec-on$in$a$building.$6. Explain$how$energy$moves$based$on$the$2nd$Law$of$
Thermodynamics.$7. Explain$why$it$is$cri-cal$for$HVAC$equipment$to$be$
sized$correctly.$
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Building$Envelope$Principles$Heat$Transfer$In$and$Out$of$the$Building$
Envelope$$$$
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Conduc-on$
Convec-on$(Infiltra-on)$
Conduc-on$
Solar$Radia-on$
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Energy$Use$in$Buildings!
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Residen-al$Total$Footage$Growth$
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Residen-al$Square$Footage$Growth$
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Residen-al$Energy$Use$Compared$to$other$Sectors$
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Growth$in$Electricity$Sales$in$Buildings$Rela-ve$to$Industry$
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Contributors$to$Electricity%Related$CO2$Emissions!
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Building$Envelope$Principles$$Bri-sh$Thermal$Unit$(Btu)$
Heat$required$to$raise$the$temperature$of$one$pound$of$water$one$degree$Fahrenheit.$Approximately$the$heat$given$off$by$a$match.$
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Building$Envelope$Principles$$Bri-sh$Thermal$Unit$(Btu)$–$Ques-on$$
$How$many$Btu$will$be$required$to$heat$50$gallons$of$water$(approximately$417$pounds)$if$the$cold$water$inlet$is$55$degrees$Fahrenheit$and$the$water$heater$is$set$at$120$degrees$Fahrenheit?$$The$first$step$is$to$find$the$Delta$T$or$temperature$rise.$$The$Delta$T$is$the$difference$in$temperature$between$55$degrees$and$120$degrees.$$$120$%$55$=$65$degrees$$The$Btu$is$equal$to$the$Delta$T$-mes$pounds$(one$to$one$ra-o).$65$x$417$=$27,105$Btu!
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Building$Envelope$Principles$$Energy$Units$Based$on$a$Btu$
$Ra-ng$for$Air$Condi-oning$
One$ton$of$cooling$=$12,000$Btu$Number$of$Btu$needed$to$melt$one$ton$of$ice$is$288,000$Btu$(12,000$x$24$hours)$
$Ra-ng$for$natural$gas$
One$therm$=$100,000$Btu$$$Ra-ng$for$electric$resistant$hea-ng$
One$kilowaC$hour$=$3413.43$Btu$1$KilowaC$heater$will$give$off$3413.43$Btu$if$leh$on$for$one$hour$$
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Building$Envelope$Principles$$Laws$of$Thermodynamics $$
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1. Conserva-on$of$Energy$
2. Movement$of$Energy$–$
Always$from$complex$to$more$simple$state$or$
Higher$temperature$to$lower$temperature.$$$$
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HDD$/$CDD$Defini-ons$Hea-ng$Degree$Days$(HDD)$
$Measure$of$the$hea-ng$severity$of$a$climate$The$colder$the$climate$the$higher$the$HDD$Based$on$65$oF$Daily$HDD$$=$65$oF$%$average$daily$temperature$$ $ $ $ $(if$less$than$65$oF)$
Annual$HDD$$=$Sum$of$Daily$HDD$over$a$ $$ $ $$$$$$calendar$year.$
Example: $Columbus $5,708$HDD$$ $$ $ $Cincinna- $5,248$HDD$
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HDD$/$CDD$Defini-ons$Cooling$Degree$Days$(CDD)$
$Measure$of$the$cooling$severity$of$a$climate$The$hoCer$the$climate$the$higher$the$CDD$Based$on$65$oF$Daily$CDD$$=$Average$daily$temperature$%$65$oF$$ $ $(if$greater$than$65$oF)$
Annual$CDD$$=$Sum$of$Daily$CDD$over$a$ $$ $ $$$$$$calendar$year.$
Example: $Columbus $797$CDD$$ $ $$$$$$$$$$$$$$ $Cincinna- $996$CDD$
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Heat Transfer
• Conduction
• Convection
• Radiation
Conduction
Conduction
Building Envelope Principles
• Conduction • The transfer of heat through a solid material,
moving from warmer to cooler particles that are in direct physical contact.
700 F 300 F
500 F
300 F
How is R-Value Determined?
Nominal R-Value is the thermal resistance of insulation alone as determined in accordance with the U.S. Federal Trade Commission R-value rule.
www.ftc.gov/bcp/rulemaking/rvalue/index.shtml
Conductive Heat Loss
What is R-value? Resistance
What is U-factor? Conductance
Both are a measurement of a material or building assembly’s heat transfer properties
R=1/U$and$U=1/R$
Reducing Conductive Heat Loss$
U-Factor Comparison
R-21 Batt insulation in 2x6 INT framed wall
(T-111 siding)
U-factor = .056
R-19 Batt insulation in 2x6 STD framed wall
+ R-5 CI
(T-111siding)
U-factor = .046
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R%Value$Defined$$
The$measure$of$the$thermal$resistance$of$a$material$or$building$component$to$the$passage$of$heat.$
R=$Delta$T/$Btu$High$R$=$Low$energy$transfer$Low$R$=$$High$energy$transfer$$$$
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1$h$
1$h$
1in.$
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R%Value$Explained$R%values$can$be$added.$
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R1$R2$
R3$R4$
• RTotal$=$R1$+$R2$+$R3$+$R4$
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R%Value$Example$$
R%Value$=$21$(Insula-on$in$Framed$2x6$Wall)$
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Climate%Specific$Requirements$Spray$Foam$Ceiling$Insula-on$
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R-11 Fiberglass Batt 11.00 Insulation 1� Cellular Polyurethane 5.00
2 X 4 @ 16� O.C. 3.46
1/2� Gypsum Board 0.45 Inside Air Film 0.68
7/8� Stucco 0.18 Outside Air Film 0.17
Total R-value = 17.48
List of Components R-value
Inside Air Film 0.68 1/2� Gypsum Board 0.45
1� Cellular Polyurethane 5.00 7/8� Stucco 0.18
Outside Air Film 0.17
List of Components R-value
Calculating the R-value Through the Wall Cavity
Calculating the R-value Through the Wall Framing
Total R-value = 9.94 Weighted R = 17.48 x .85 + 9.94 x .15 = 16.34
• U%factor$(Btu/h2%oF%hr)$– The$overall$coefficient$of$heat$transmission$and$the$rate$of$heat$flow$through$the$various$materials$of$a$construc-on$assembly.$
– U%factor$=$1/Rtotal$– Used$to$calculate$hea-ng$and$cooling$loads$
Building$Envelope$Principles$
U%factor$Example$Fenestra-on$U%factor$
• NFRC$Ra-ng$for$all$Manufactured$Fenestra-on;$or$
• Tables102.5.2(1)$U%factor$Default$Table$for$Windows,$Glazed$Doors$and$Skylights$
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Misalignment$$
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Insulation is not touching the sheetrock air barrier.
R-0.45
Sketch Courtesy of Advanced Energy Corporation
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Standard$Roof$Truss$
Ceiling$insula-on$code$requirements$assume$standard$truss$systems.$
Cold$corners$contribute$to$condensa-on$and$mold$growth$
Possibility$of$ice$dam$forma-ons$
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Raised$Heel$Truss$
Excep&on)! Raised$Heel/Energy$Truss$credit$if$insula-on$is$
full$height$over$exterior$wall$(Prescrip)ve)$$
R%30$instead$of$R%38$R%38$instead$of$R%49$$
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Annual Cost of Conductive Heat Loss
Transmission Heat Flow Equation
House with R-21 walls, 2240 CFA
UA x HDD x 24hrs/day
where UA is 336
6835 HDD in Spokane, WA
Annual cost of conductive heat loss in Spokane WA:
55,117,440 BTUs annually
Electric resistance heat = $1,208 ($.083/kWh)
2.64 COP DHP = $458 ($0.083/kWh)
2.2 COP ASHP = $535 ($0.083/kWh)
80 AFUE NG Furnace = $652 ($1.05/therm)
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Annual Cost of Conductive Heat Loss House with R-5 Foam
Transmission Heat Flow Equation
House with R-19 + R-5 walls, 2240 CFA
UA x HDD x 24hrs/day
where UA is 306
6835 HDD in Spokane, WA
Annual cost of conductive heat loss in Spokane WA:
50,196,240 BTUs annually
Electric resistance heat = $1,100 ($.083/kWh)
2.64 COP DHP = $417 ($0.083/kWh)
2.2 COP ASHP = $488 ($0.083/kWh)
80 AFUE NG Furnace = $594 ($1.05/therm)
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Building$Envelope$Principles$$Convec-on$$
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$The$transfer$of$heat$through$a$moving$fluid,$either$gas$or$liquid.$$The$most$common$driving$force$for$convec-ve$heat$transfer$is$the$tendency$of$a$warm$fluid$to$rise$due$to$its$lighter$density.$
Convec-on$(Infiltra-on)$
700$F$
300$F$
500$F$
300$F$
Convec-on$Drivers$
Wind
Fans and Mechanical Systems Stack Effect
Airflow$affects$comfort$
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Building$Envelope$Principles$$Vapor$Retarders$–$Basic$Requirements$2009$IRC$R601.3.2$–$2012$IRC$R702.7$$Install$on$�warm%in%winter$side�$of$insula-on$or$
inside$of$frame$wall.$$$
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Siding!!Outside!Sheathing!!Studs!&!Insula1on!!Vapor!Retarder!!Sheetrock!
Vapor!
IRC$VR$Classifica-on$–$R702.7.2$(2012)$$
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Class$I:$$Sheet$Polyethylene,$unperforated$aluminum$foil$$Class$II:$$Krah%faced$fiberglass$baCs$$Class$III:$$Latex$or$enamel$paint$$$
Building$Envelope$Principles$$Vapor$Pressure$$$
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High$Vapor$
Pressure$
• $cooking$• $showers$• $other$
20oF!
Low$Vapor$Pressure$
February$12$Boise$$Outside$RH$=$82%$OT$=$41degrees$Inside$RH$=$43%$IT$=$65$degrees$$
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Building$Envelope$Principles$$Vapor$Retarders$$
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Building$Envelope$Principles$$Vapor$Retarders$–$Latex$paint$may$qualify$$
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IRC$R601.3.1$Latex$or$enamel$paint$are$considered$a$$
Class$III$Vapor$Retarder$
Website:$hCp://www.naima.org$
Building$Envelope$Principles$$NAIMA$Insula-on$Facts$#4$–$Vapor$Retarders$
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The main reason to retard the transmission of water vapor through building envelopes is to prevent it from condensing to liquid water within the structure.
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Building$Envelope$Principles$$NAIMA$Insula-on$Facts$#4$–$Vapor$Retarders$
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What Determines How �Tight� a Vapor Retarder is Required in Walls? �In general, the colder the climate, the tighter the vapor retarder should be. Also, the more vapor- tight the building�s outer skin, the tighter the vapor retarder should be.�
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Building$Envelope$Principles$$NAIMA$Insula-on$Facts$#4$–$Vapor$Retarders$
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How are Condensation Problems Avoided in Cathedral (Sloped) Ceilings? �Since commonly used asphalt roof shingles have very low vapor permeance, cathedral ceilings can be likened to walls with very low permeance exterior skins. As in walls, the use of very tight, continuous vapor retarders can prevent condensation problems in cathedral ceilings. Problems can occur, however, if a vapor retarder is not continuous.�
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Building$Envelope$Principles$$Radia-on$
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Solar$Radia-on$
$The$transfer$of$heat$by$electromagne-c$waves$from$a$warmer$to$a$cooler$surface,$where$the$medium$is$not$affected$by$the$transfer.$$To$transfer$heat$by$radia-on$from$one$surface$to$the$another,$the$surface$temperatures$must$be$different.$
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Solar$Spectrum$$$
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Ultraviolet 2%
Visible Light 47%
Infrared 51%
Ultraviolet Visible Light Infrared
Solar$Heat$Gain$Coefficient$Windows$$$
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Solar$Heat$Gain$Coefficient$(SHGC)$
The$ra-o$of$the$solar$heat$gain$entering$the$space$through$the$fenestra-on$area$to$the$incident$solar$radia-on$
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Incident$Solar$Radia-on$
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Reflec-ve$Coa-ngs$Reflects$both$heat$and$light$–$�Solar$Mirror�$$$$
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Reflects Light$Inward Radiation Reduced$
Direct Transmittance Reduced$
Reflects Heat$
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Emissivity$(e.g.$Low%E)$The$ability$of$a$material$to$absorb$and$reradiate$
heat$$$
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Reflectance$Inward Radiation Gain$
Direct Transmittance$
Outward Radiation$
Fenestra-on$SHGC$Requirements$
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SHGC$0.32$
SHGC$Examples$$$$
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SHGC$=$0.33$
HVAC$Systems$
• Hea-ng$and$cooling$efficiency$terminology$– (AFUE)$%$Annual$Fuel$U-liza-on$Efficiency$
– (HSPF)$%$Hea-ng$Seasonal$Performance$Factor$
– (SEER)$%$Seasonal$Energy$Efficiency$Ra-o$
(MPG) - Miles Per Gallon
Energy$Efficient$Mechanical$Design$
$$$$IECC$and$IRC$accomplishes$by:$$
– Requiring$minimum$equipment$performance$
– Requiring$the$sizing$of$equipment$– Minimizing$distribu-on$losses$– Op-mizing$system$controls$(commercial)$– Taking$advantage$of$free$cooling$(commercial)$
HVAC$Systems$$
• HVAC$System$Sizing$Based$On$– Indoor$Design$Temperatures$– Outdoor$Design$Temperatures$– Conduc-ve$losses$and$gains$– Convec-ve$losses$and$gains$– Solar$radia-on$gains$– Internal$Loads$$– Ven-la-on$(Commercial$Buildings)$
• Hea-ng$and$Cooling$Design$Temperatures$– Indoor$design$temperatures$$– Based$on$the$ASHRAE$Comfort$Envelope$
• Accounts$for$humidity$and$temperature$
– Factor$in$proposed$ac-vity$for$the$space$– Typical$cooling$temperatures$
• 70$oF$$%$$78$oF$– Typical$hea-ng$temperatures$
• 68$oF$%$75$oF$
HVAC$Systems$
• Hea-ng$and$Cooling$Design$Temperatures$– Outdoor$design$temperatures$
• Used$for$sizing$hea-ng$and$cooling$systems$• Winter$Design$Dry%Bulb$99%$
– Temperatures$will$only$drop$below$1%$of$the$-me$between$November$through$February$
HVAC$Systems$
• Hea-ng$and$Cooling$Design$Temperatures$– Outdoor$design$temperatures$(con�t)$
• Summer$Design$Dry%Bulb $1%$– Temperatures$which$have$been$equaled$or$exceeded$1%$of$the$-me$between$June$through$September$
• Summer$Design$Wet%Bulb$ $1%$– Average$of$all$the$wet$bulb$temperatures$occurring$at$the$specific$dry%bulb$temperature$
HVAC$Systems$
• Space$Condi-oning$Through$Forced$Air$Systems$– Duct$system$design$based$on$
• Pressure$difference$• Fric-on$in$the$duct$system$• Velocity$of$the$air$in$the$duct$system$• Diameter$of$the$duct$$• Volume$of$air$flowing$through$the$duct$system$
HVAC$Systems$
Typical Heating and Cooling Systems
FURNACE
A/C UNIT
Ductwork
Heating and Cooling Efficiency
Temperature & Humidity Controls
Duct Installation and Insulation
Pipe Insulation
HVAC$System$%$Residen-al$
• Refrigera-on$Cycle$HVAC$Systems$
Outdoor Indoor
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Impact$of$Installa-on$Factors$on$Heat$Pumps$&$Central$A/C$$
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5!6!7!8!9!
10!11!12!13!
10! 11! 12! 13! 14!Rated SEER!
Typical Installation
Correct Flow 0.5 Proper Charge 1.5
Sized Right .75 Airtight Ducts 2.0
Fiel
d A
djus
ted
SEER
[SEE
RFA
]!
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