BCT 211 Notes.pdf - September 6 2016 Maxims Build tight...

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Unformatted text preview: September​ ​6,​ ​2016 Maxims - Build​ ​tight,​ ​ventilate​ ​right - More​ ​insulation​ ​is​ ​better - Better​ ​glass,​ ​only​ ​where​ ​you​ ​need​ ​it - Turn​ ​it​ ​off​ ​if​ ​it’s​ ​not​ ​being​ ​used - Keep​ ​it​ ​dry​ ​and​ ​let​ ​it​ ​dry - Don’t​ ​blow​ ​or​ ​suck​ ​on​ ​walls,​ ​floors​ ​or​ ​ceilings - Tubes​ ​should​ ​be​ ​short,​ ​fat,​ ​straight​ ​and​ ​leak-free - Efficiency​ ​pays - Compare​ ​apples​ ​to​ ​apples - A​ ​building​ ​is​ ​a​ ​system,​ ​not​ ​the​ ​sum​ ​of​ ​its​ ​parts - It​ ​matters​ ​where​ ​you​ ​are Buildings,​ ​What​ ​Do​ ​we​ ​Want​ ​from​ ​Them? Housing - Protection​ ​from​ ​elements - Comfort - Community - Security - Economic - Physical - Psychological - Location:​ ​work,​ ​school,​ ​“home” - Keep​ ​all​ ​our​ ​stuff - Increasingly​ ​includes​ ​consumer​ ​electronics Commercial/Institutional - Protection​ ​from​ ​elements - Comfort - Community - Security - Economic - Physical - Psychological - Location:​ ​workers,​ ​customers,​ ​suppliers,​ ​industry​ ​hub,​ ​inputs - Inventory,​ ​IT What​ ​is​ ​energy​ ​efficient​ ​housing? Some​ ​keys: - Insulation - Recycled​ ​materials - Energy​ ​efficient​ ​lighting:​ ​automation,​ ​specific​ ​tech​ ​(LED),​ ​renewable​ ​energy​ ​(PV) - Water​ ​efficiency/reutilization​ ​(greywater,etc),​ ​responsible​ ​sourcing - Minimize​ ​thermal​ ​bridging - Responsible​ ​sourcing​ ​of​ ​heat​ ​(passive,​ ​renewable)​ ​for​ ​occupied​ ​space​ ​and​ ​hot​ ​water. - Landscaping​ ​(water​ ​consumption​ ​has​ ​huge​ ​impact​ ​vs.​ ​domestic​ ​consumption) - Efficient​ ​HVAC - Mitigation​ ​of​ ​runoff - Carefully​ ​placed​ ​windows,​ ​building​ ​orientation - Weatherization How​ ​to​ ​improve​ ​building​ ​energy​ ​efficiency? Technology - Building​ ​elements - New​ ​technologies - New​ ​buildings - Old​ ​buildings - Whole​ ​building​ ​system​ ​approach Policy - Finance - Regulatory - Incentives - Cultural​ ​change Building​ ​System - Environment​ ​(external,​ ​internal,​ ​personal)​ ​→ - Building​ ​Enclosure​ ​(Roof,walls,​ ​foundation,​ ​windows)​ ​→ - Mechanical​ ​Systems​ ​(heating​ ​cooling,​ ​ventilation,​ ​lighting,​ ​plug​ ​loads)​ ​→ - People​ ​(Physiology,​ ​Psychology,​ ​Behavior) Role​ ​of​ ​Housing Adapt​ ​to​ ​Constraints​ ​and​ ​Challenges - Increasingly​ ​expensive​ ​energy - Utility​ ​services​ ​limitations - Harsher​ ​climate​ ​with​ ​greater​ ​temperature​ ​and​ ​moisture​ ​variability - Bigger,​ ​more​ ​frequent​ ​storms - Better​ ​environment​ ​for​ ​pathogens​ ​and​ ​pests - Population​ ​shifts - Reduced​ ​arable​ ​land Mitigate​ ​Worst​ ​Scenarios - Resource​ ​wars - Food​ ​scarcity - A​ ​climate​ ​inhospitable​ ​to​ ​humans​ ​and​ ​most​ ​of​ ​the​ ​environment September​ ​8,​ ​2016 What​ ​is​ ​energy? - “The​ ​capacity​ ​for​ ​doing​ ​work” - Work​ ​=​ ​force​ ​x​ ​distance - A​ ​measurable​ ​quantity​ ​of​ ​heat,​ ​work,​ ​or​ ​light - Units:​ ​BTU,​ ​Joules,​ ​watt-hour​ ​(Wh) - An​ ​actual​ ​amount​ ​of​ ​energy​ ​produced​ ​or​ ​consumed - Energy​ ​=​ ​power​ ​x​ ​time Forms​ ​of​ ​Energy - Kinetic​ ​energy:​ ​energy​ ​of​ ​motion - Thermal​ ​energy:​ ​heat - Chemical​ ​energy:​ ​stored​ ​energy​ ​(fuels,​ ​food,​ ​C-H​ ​bonds,​ ​H2​ ​bonds) - Electricity:​ ​carried​ ​through​ ​circuits - Light:​ ​how​ ​energy​ ​gets​ ​from​ ​the​ ​sun​ ​to​ ​the​ ​earth - Nuclear​ ​energy:​ ​the​ ​energy​ ​in​ ​the​ ​sun - Potential​ ​energy:​ ​energy​ ​stored​ ​before​ ​being​ ​used Law​ ​of​ ​Thermodynamics - First​ ​law:​ ​Energy​ ​is​ ​not​ ​destroyed​ ​or​ ​created,​ ​it​ ​is​ ​simply​ ​transformed - Second​ ​law​ ​(Entropy​ ​Law):​ ​it’s​ ​not​ ​reversible.​ ​There​ ​is​ ​always​ ​waste​ ​in​ ​any​ ​energy transformation.​ ​Everything​ ​goes​ ​from​ ​high​ ​concentration​ ​to​ ​low. - From​ ​high​ ​quality​ ​to​ ​low - From​ ​high​ ​temperature​ ​to​ ​low - From​ ​high​ ​potential​ ​energy​ ​to​ ​low - From​ ​high​ ​pressure​ ​to​ ​low - It​ ​takes​ ​a​ ​lot​ ​of​ ​low​ ​entropy​ ​to​ ​make​ ​even​ ​lower​ ​entropy Power - Power​ ​=​ ​energy/time - The​ ​rate​ ​at​ ​which​ ​work​ ​is​ ​performed​ ​or​ ​energy​ ​is​ ​converted - Units:​ ​Btu/hour​ ​(Btuh),​ ​Watts​ ​(W) - Describes​ ​a​ ​capacity​ ​or​ ​rating - 1​ ​watt​ ​=​ ​3.412​ ​Btu/hr - 1​ ​watt/m^2​ ​=​ ​0.317​ ​Btuh/ft^2 Efficiency - Efficiency​ ​=​ ​output/input - Example: - Employee​ ​1:​ ​$15/hr,​ ​$100​ ​sales/hr​ ​=​ ​100/15=​ ​6.667 - Employee​ ​2:​ ​$20/hr,​ ​$150​ ​sales/hr=​ ​150/20​ ​=​ ​7.50 - Input​ ​=​ ​output​ ​(1st​ ​law) - Input​ ​>​ ​useful​ ​output​ ​(2nd​ ​Law) - Example: - Rated​ ​output​ ​is​ ​100​ ​kBtu/h - Fuel​ ​input​ ​is​ ​120​ ​kBtu/h - 100/120​ ​=​ ​0.83​ ​or​ ​83%​ ​efficient - Heat​ ​Pump​ ​Efficiency - Example: - Output​ ​=​ ​100​ ​kBtu/h - Input​ ​=​ ​12​ ​kW - 100​ ​kBtu/h​ ​=​ ​29.307​ ​kW - 29.307/12​ ​=​ ​2.44​ ​(244%​ ​efficient) Q=​ ​m​ ​x​ ​(T1-​ ​T2)​ ​x​ ​C September​ ​15,​ ​2016 Lighting​ ​design​ ​goals - Provide​ ​sufficient​ ​light​ ​for​ ​a​ ​variety​ ​of​ ​daily​ ​functions - Use​ ​as​ ​little​ ​electricity​ ​as​ ​possible - Use​ ​daylighting - Minimize​ ​glare​ ​and​ ​discomfort,​ ​and​ ​thermal​ ​gains/losses Incandescent - Efficacy​ ​=​ ​13.66​ ​lm/W​ ​for​ ​a​ ​820​ ​lumen​ ​lightbulb.​ ​Uses​ ​60​ ​W Compact​ ​Fluorescent - Efficacy​ ​=​ ​66.9​ ​lm/W​ ​for​ ​a​ ​870​ ​lumen​ ​lightbulb.​ ​Uses​ ​only​ ​13​ ​W Phillips​ ​LED - Efficacy​ ​=​ ​75​ ​lm/W​ ​for​ ​a​ ​870​ ​lumen​ ​lightbulb,​ ​Uses​ ​11​ ​W CREE​ ​LED - Effiacy​ ​=​ ​84.21​ ​lm/W​ ​for​ ​a​ ​800​ ​lumen​ ​lightbulb.​ ​Uses​ ​9.5​ ​W Units - Roughly,​ ​1​ ​candlepower​ ​~​ ​1​ ​candela​ ​(Cd) - 1​ ​cd​ ​=​ ​1​ ​lm/sr Flow​ ​and​ ​Intensity - Lumen​ ​(lm):​ ​luminous​ ​flux,​ ​the​ ​total​ ​flow​ ​of​ ​light​ ​from​ ​a​ ​source - Lm=​ ​cd​ ​x​ ​sr - Candela Illuminance​ ​and​ ​Luminance - Lux​ ​(lx)​ ​or​ ​Footcandles​ ​(fc):​ ​illuminance​ ​or​ ​luminous​ ​flux​ ​density,​ ​the​ ​amount​ ​of​ ​light falling​ ​on​ ​a​ ​surface - 1​ ​lx​ ​=​ ​1​ ​lm/m^2 - Cd​ ​=​ ​lm​ ​x​ ​m^2 - This​ ​is​ ​the​ ​square​ ​of​ ​the​ ​distance​ ​from​ ​the​ ​light​ ​source​ ​to​ ​the​ ​illuminated​ ​surface - 1​ ​fc​ ​=​ ​1​ ​lm/ft^2 - cd/m^2​ ​=​ ​luminance,​ ​apparent​ ​brightness​ ​of​ ​a​ ​surface - Human​ ​eye​ ​can​ ​work​ ​from​ ​0.1​ ​lux​ ​to​ ​100,000​ ​lux! How​ ​Much​ ​is​ ​Enough? - Ambient:​ ​Orientation,​ ​safety,​ ​security​ ​(50-250​ ​lux) - Task:​ ​reading,​ ​detail​ ​work,​ ​cooking,​ ​makeup​ ​(200-1000​ ​lux) - Accent​ ​lighting:​ ​aesthetic​ ​uses​ ​(can​ ​contribute​ ​to​ ​ambient​ ​lighting)​ ​(Defined​ ​by​ ​needed luminance,​ ​generally​ ​2xambient) - We​ ​need​ ​to​ ​measure​ ​it Contrast​ ​is​ ​Key - Contrast​ ​between​ ​a​ ​visual​ ​target​ ​and​ ​the​ ​background​ ​must​ ​be​ ​sufficient​ ​to​ ​clearly​ ​view the​ ​task - 1:3:10​ ​the​ ​task​ ​area​ ​should​ ​be​ ​3​ ​times​ ​brighter​ ​than​ ​the​ ​immediate​ ​surrounding​ ​and​ ​10 times​ ​brighter​ ​than​ ​the​ ​peripheral​ ​area - Excessive​ ​contrast​ ​levels September​ ​20,​ ​2016 Residential​ ​EIU - Floor​ ​space​ ​is​ ​not​ ​the​ ​key​ ​value - Small​ ​house​ ​penalty - Basement - Weather​ ​effects House​ ​to​ ​House​ ​Comparison - House​ ​1: - Oil​ ​heat:​ ​800​ ​gal/yr - Electric​ ​Use:​ ​7200​ ​kWh/​ ​yr - 1800​ ​sq​ ​ft​ ​(167​ ​m^2) - 4​ ​people - 39,520​ ​kWh​ ​total - 5.48/person/​ ​sq​ ​ft - House​ ​2: - Gas​ ​heat:​ ​1000​ ​therms/yr - Electric​ ​use:​ ​5400​ ​kWh/yr - 3000​ ​sq​ ​ft​ ​(278​ ​m^2) - 2​ ​people - 35,700​ ​kWh​ ​total - 5.78/person/sq​ ​ft Fuel Typical​ ​Units kBtu kWh Electricity kWh 3.412 1.0 Natural​ ​Gas Therms 10.00 29.3 Fuel​ ​Oil Gallons 138.00 40.4 Benchmarking - Very​ ​difficult​ ​with​ ​residential - Average:​ ​60​ ​kBtu/sf/yr - Home​ ​Heating​ ​Index: - Btu/(sf​ ​x​ ​HDD​ ​x​ ​yr) Heating​ ​Degree​ ​Days​ ​(HDD) - How​ ​much​ ​(in​ ​degrees)​ ​and​ ​for​ ​how​ ​long​ ​(in​ ​days),​ ​outside​ ​air​ ​temp​ ​was​ ​lower​ ​than​ ​a spec.​ ​“Base​ ​temp.” - Standard​ ​base​ ​temp:​ ​US:​ ​65​ ​d​ ​F​ ​(18​ ​C),​ ​but​ ​EU​ ​(15​ ​C) - Example: - Jan​ ​1,​ ​2011​ ​(mean​ ​temp:​ ​37​ ​F,​ ​base​ ​=​ ​65​ ​F,​ ​one​ ​day) - 65-37​ ​=​ ​28​ ​HDD - Jan​ ​2​ ​HDD​ ​=​ ​25,​ ​etc - Monthly​ ​HDD​ ​=​ ​Sum​ ​of​ ​daily​ ​HDD​ ​for​ ​month September​ ​29,​ ​2016 Building​ ​Energy​ ​Flow:​ ​Design House​ ​Energy​ ​Balance - Inputs: - HVAC​ ​systems - Internal​ ​gains - Solar​ ​Gains - Outputs: - Heat​ ​leakage - Conduction - air​ ​exchange - radiation - Enthalpy​ ​Losses Energy​ ​Conversion​ ​Inefficiency Heat​ ​Transfer - Hot​ ​→​ ​cold - ΔT​ ​=​ ​T​1​-T​2 - ΔT​ ​=​ ​T​in​-T​out - Types​ ​of​ ​heat​ ​transfer - Conduction​:​ ​through​ ​a​ ​material - Convection​:​ ​carried​ ​by​ ​fluid - Mass​ ​Transfer​:​ ​movement​ ​of​ ​a​ ​material​ ​that​ ​carries​ ​heat​ ​with​ ​it - Radiation:​ ​surface​ ​to​ ​surface - Latent​ ​Heat​:​ ​the​ ​energy​ ​released​ ​(or​ ​required)​ ​for​ ​phase​ ​(state)​ ​change Conduction - Hot​ ​to​ ​cold - Energy​ ​is​ ​transferred​ ​from​ ​more​ ​energetic​ ​to​ ​less​ ​energetic​ ​molecules​ ​when​ ​neighboring molecules​ ​collide - Fourier’s​ ​Law - Q​ ​=​ ​k​ ​x​ ​A​ ​x​ ​ΔT​ ​/​ ​s - Q​ ​=​ ​heat​ ​transfer​ ​rate​ ​(W,​ ​Btu/h) - A​ ​=​ ​heat​ ​transfer​ ​area​ ​(m​2​,​ ​ft​2​) Assembly​ ​Conductivity U​ ​Factor - Units:​ ​1​ ​Btu/hr​ ​x​ ​ft​2​​ ​x​ ​degrees​ ​F​ ​=​ ​1.731​ ​W/m​2​.K - The​ ​lower​ ​the​ ​number​ ​the​ ​better​ ​the​ ​insulation! - Resistance​ ​to​ ​heat​ ​flow:​ ​R-value​ ​=​ ​1/U - 1​ ​(hr​ ​x​ ​ft​2​​ ​x​ ​degrees​ ​F/Btu)​ ​=​ ​0.176​ ​k​ ​x​ ​m2​​ /W - The​ ​higher​ ​the​ ​number​ ​the​ ​better​ ​the​ ​insulation - Typical​ ​R​ ​values​ ​(US): - Walls:​ ​19 - Roof:​ ​40 - “Modern”​ ​windows:​ ​3 Advanced​ ​Framing - 24”​ ​OC​ ​instead​ ​of​ ​16” - Save​ ​lumber​ ​(25-30%) - Reduce​ ​labor - Reduce​ ​scrap Reduce​ ​drywall​ ​cracking​ ​and​ ​simplify​ ​air​ ​sealing October​ ​4,​ ​2016 Conductive​ ​Heat​ ​Loss ​ ​ ​ ​ ​ ​Q​ ​=​ ​U*A*​ ​delta​ ​T - Q=​ ​heat​ ​loss​ ​(Btu/hr,​ ​W) - A=​ ​area - U=​ ​1/R - Delta​ ​T=​ ​temperature​ ​difference​ ​(degrees​ ​F,​ ​degrees​ ​C​ ​or​ ​K)​ ​=​ ​T1-T2 - Use​ ​design​ ​or​ ​actual​ ​temp​ ​for​ ​outdoor - Design​ ​temperature:​ ​the​ ​temperature​ ​that​ ​is​ ​exceeded​ ​98%​ ​of​ ​the​ ​time​ ​(i.e.​ ​way​ ​colder than​ ​it​ ​will​ ​usually​ ​be) Convection - heat​ ​travels​ ​along​ ​with​ ​a​ ​fluid - Temp​ ​differences​ ​(relative​ ​buoyancy)​ ​drives​ ​fluid​ ​movement - Reducing​ ​air​ ​flow​ ​reduces​ ​convection Convective​ ​Loops - Convection​ ​loops​ ​circulate​ ​near​ ​walls. - During​ ​the​ ​heating​ ​season,​ ​warm​ ​air​ ​is​ ​cooled​ ​by​ ​exterior​ ​walls​ ​and​ ​falls​ ​toward​ ​the​ ​floor, creating​ ​a​ ​convective​ ​loop.​ ​Convective​ ​loops​ ​can​ ​also​ ​happen​ ​within​ ​framing​ ​cavities​ ​if the​ ​insulation​ ​doesn't​ ​completely​ ​fill​ ​the​ ​space. Air​ ​Leakage - High​ ​Pressure​ ​->​ ​Low​ ​Pressure - Stack​ ​effect - Wind - Mechanical - Requires: - Pressure​ ​difference​ ​between​ ​two​ ​points - Continuous​ ​flow​ ​path​ ​or​ ​opening​ ​connecting​ ​the​ ​points Stack​ ​Effect - warm​ ​air​ ​rises​ ​and​ ​escapes - Cold​ ​air​ ​is​ ​sucked​ ​into​ ​replace​ ​it - Requires:​ ​height,​ ​cold​ ​outdoor​ ​temperature,​ ​and​ ​air​ ​leakage October​ ​6,​ ​2016 Annual​ ​Air​ ​Leakage​ ​Heat​ ​Loss - Q​ ​-​ ​0.018​ ​x​ ​V​ ​x​ ​ACH​ ​x​ ​delta​ ​T​ ​x​ ​Time - Replace​ ​delta​ ​T​ ​x​ ​Time​ ​with​ ​HDD - QBtu​ ​=​ ​0.018​ ​Btu​ ​x​ ​Vft^3​ ​x​ ​ACH​ ​x​ ​HDD​ ​x​ ​24h/day Air​ ​Leakage​ ​Heat​ ​Loss Q=​ ​1.08​ ​x​ ​CFMn​ ​x​ ​HDD​ ​x​ ​24 - Q=​ ​Btu​ ​lost​ ​from​ ​air​ ​turnover - CFM​ ​=​ ​Air​ ​infiltration​ ​(VR​ ​=​ ​ventilation​ ​rate) - 1.08​ ​=​ ​heat​ ​capacity​ ​of​ ​a​ ​cubic​ ​foot​ ​of​ ​air​ ​over​ ​one​ ​hour​ ​(at​ ​sea​ ​level) - HDD​ ​=​ ​heating​ ​degree​ ​days - 24​ ​hours​ ​in​ ​a​ ​day Example A​ ​single​ ​story​ ​ranch​ ​house​ ​has​ ​a​ ​ventilation​ ​system​ ​that​ ​exhausts​ ​100​ ​CFM.​ ​It​ ​experiences​ ​6000 HDD​ ​in​ ​a​ ​typical​ ​heating​ ​season.​ ​What​ ​is​ ​annual​ ​heat​ ​loss? - 1.08​ ​x​ ​100​ ​x​ ​6000​ ​x​ ​24​ ​=​ ​15,552,000 - Cost​ ​is​ ​$1.40​ ​per​ ​therm​ ​=​ ​$206.84 Plug​ ​Loads - Major​ ​Residential​ ​uses​ ​of​ ​Electricity​ ​in​ ​the​ ​US - Heating - Cooling - Water​ ​heating - Lighting - Refrigeration - “Other” - More​ ​than​ ​⅔​ ​of​ ​“other”​ ​may​ ​be​ ​phantom​ ​standby Set-Top​ ​Boxes -​ ​160-million​ ​set-top​ ​boxes​ ​installed​ ​in​ ​US​ ​homes Almost​ ​all​ ​owned October​ ​13,​ ​2016​ ​Radiation House​ ​Energy​ ​Balance - Input - HVAC​ ​Systems - Internal​ ​Gains - Solar​ ​Gains - Output​ ​(Heat​ ​Leakage) - Conduction - Convection - Air​ ​exchange - Radiation Radient​ ​Heat​ ​Transfer - Heat​ ​travels​ ​though​ ​space​ ​from​ ​one​ ​surface​ ​to​ ​another - Emissivity​ ​-​ ​how​ ​much​ ​radiant​ ​energy​ ​is​ ​emitted​ ​by​ ​a​ ​surface​ ​(comp.​ ​To​ ​a​ ​perfect emitter) - Absorptivity:​ ​how​ ​much​ ​radiant​ ​energy​ ​is​ ​absorbed​ ​by​ ​a​ ​surface​ ​compared​ ​to​ ​a​ ​perfect absorber - E=A - Reflectivity​ ​is​ ​the​ ​inverse​ ​of​ ​emissivity Enthalpy​ ​and​ ​Latent​ ​Heat - Why​ ​does​ ​a​ ​fan​ ​make​ ​you​ ​feel​ ​cooler? - Moving​ ​air​ ​cools​ ​you​ ​off​ ​by​ ​evaporating​ ​your​ ​sweat - Latent​ ​Heat​ ​of​ ​Phase​ ​Change - Sensible​ ​Heat:​ ​heat​ ​you​ ​can​ ​sense - Latent​ ​Heat:​ ​the​ ​energy​ ​needed​ ​to​ ​change​ ​a​ ​substance​ ​to​ ​a​ ​higher​ ​state​ ​of​ ​matter. This​ ​same​ ​energy​ ​is​ ​released​ ​from​ ​the​ ​substance​ ​when​ ​the​ ​change​ ​of​ ​state​ ​is reversed - Humidity​ ​Ratio:​ ​mass​ ​of​ ​water​ ​vapour​ ​/​ ​mass​ ​of​ ​dry​ ​air October​ ​18,​ ​2016 Latent​ ​Cooling​ ​Load - Rate​ ​of​ ​energy​ ​use​ ​to​ ​remove​ ​a​ ​latent​ ​load​ ​depends​ ​on: - Humidity​ ​ratio​ ​(how​ ​much​ ​moisture/unit​ ​of​ ​air) - Air​ ​flow​ ​(how​ ​much​ ​air) - Enthalpy​ ​of​ ​condensation​ ​per​ ​unit​ ​of​ ​air Example AC​ ​house​ ​with​ ​air​ ​leakage​ ​at​ ​a​ ​rate​ ​of​ ​100​ ​CFM​ ​with​ ​indoor​ ​set​ ​point​ ​at​ ​75​ ​deg​ ​F​ ​and​ ​50%​ ​RH. Outside​ ​air​ ​is​ ​88​ ​deg​ ​F​ ​and​ ​50%​ ​RH.​ ​How​ ​much​ ​latent​ ​heat​ ​must​ ​be​ ​removed​ ​each​ ​hour​ ​due​ ​to air​ ​leakage? - Outside:​ ​0.15 - Inside:​ ​0.09 - .15-.09​ ​=​ ​0.006 - QL​ ​=​ ​0.006​ ​x​ ​100​ ​x​ ​4842​ ​=​ ​2905.2 Clothes​ ​dryer - Clothes​ ​dryer​ ​power:​ ​2000​ ​W - Dry​ ​one​ ​load​ ​in​ ​40​ ​min - Exhaust​ ​air​ ​flow:​ ​150​ ​CFM - AC​ ​maintains​ ​74​ ​deg​ ​F​ ​and​ ​50%​ ​RH - AC​ ​has​ ​EER​ ​of​ ​13 - Elec.​ ​costs​ ​$0.14​ ​per​ ​kWh Outside​ ​air​ ​averages​ ​90​ ​deg​ ​F​ ​and​ ​60​ ​RH What​ ​is​ ​cost​ ​of​ ​drying​ ​one​ ​load​ ​of​ ​laundry? Cost​ ​of​ ​dryer​ ​load​ ​at​ ​laundromat​ ​is​ ​$1.50 October​ ​21,​ ​2016 Portable​ ​AC:​ ​What​ ​is​ ​the​ ​net​ ​impact? •Rating​ ​7000​ ​Btu/h •Fan​ ​Flow:​ ​180​ ​CFM •820​ ​W​ ​Input •Inside​ ​set​ ​point: ◦75​ ​F ◦50%​ ​RH ◦Springfield​ ​Design​ ​Day •90F •50%​ ​RH Moisture​ ​in​ ​Attics - Before​ ​the​ ​insulation​ ​the​ ​attic​ ​was​ ​warm,​ ​so​ ​warm​ ​moist​ ​air​ ​could​ ​escape​ ​before condensing Reduce​ ​Moisture​ ​Problems​ ​by​ ​Reducing​ ​Moisture - Reduce​ ​Rel.​ ​Humidity​ ​by​ ​increasing​ ​temp,​ ​dehumidification,​ ​and​ ​increase​ ​controlled ventilation - Reduce​ ​bulk​ ​moisture​ ​intrusion,​ ​reduce​ ​exposure​ ​to​ ​moisture​ ​loads​ ​like​ ​bare​ ​earth, uncovered​ ​fish​ ​tanks,​ ​etc - Exhaust​ ​spot​ ​moisture​ ​loads​ ​(kitchens,​ ​bathrooms,​ ​clothes​ ​dryers) Source,​ ​Driving​ ​Force,​ ​Path - Sources:​ ​bulk​ ​moisture,​ ​water​ ​vapor,​ ​thermal​ ​bypasses,​ ​heat​ ​gains​ ​(intentional​ ​or otherwise) - Forces:​ ​Pressure​ ​and​ ​temperature​ ​differences,​ ​capillary​ ​action, October​ ​25,​ ​2016 Enclosure​ ​System - Roof​ ​system - Above​ ​grade​ ​wall​ ​system​ ​including​ ​windows​ ​and​ ​doors - Below​ ​grade​ ​wall​ ​system - Base​ ​floor​ ​system - Each​ ​is​ ​multi-layer,​ ​multi-material,​ ​multi-function​ ​assembly​ ​from​ ​inside​ ​to​ ​out Control​ ​Layers 1. Water 2. Air 3. Conduction 4. Vapor October​ ​27,​ ​2016 Object:​ ​control​ ​air​ ​flow - Energy​ ​savings - 30-50%​ ​of​ ​space​ ​conditioning​ ​energy​ ​consumption​ ​in​ ​many​ ​well-insulated buildings​ ​is​ ​due​ ​to​ ​air​ ​leakage​ ​through​ ​the​ ​building-enclosure - Convective​ ​circulation​ ​and​ ​windwashing​ ​reduce​ ​insulation​ ​effectiveness - Moisture​ ​control - Water​ ​vapor​ ​moves​ ​on​ ​air​ ​and​ ​can​ ​condense​ ​within​ ​the​ ​enclosure​ ​system - Comfort​ ​and​ ​health - Drafts​ ​and​ ​dry​ ​wintertime​ ​air​ ​reduce​ ​comfort - Air​ ​cooled​ ​interior​ ​surfaces​ ​can​ ​condense​ ​moisture​ ​and​ ​promote​ ​mold​ ​growth - Reduce​ ​exposure​ ​to​ ​pollution​ ​(e.g.​ ​garage) Control​ ​Ventilation - Any​ ​air​ ​sealing​ ​plan​ ​should​ ​involve​ ​a​ ​plan​ ​to​ ​provide​ ​adequate​ ​ventilation - ASHRAE​ ​standard​ ​62: - Old:​ ​0.35​ ​ACH​ ​(air​ ​changes​ ​per​ ​hour) - New:​ ​1​ ​cfm/300ft^2​ ​+​ ​7.5​ ​CFM​ ​per​ ​occupant Air​ ​Barrier​ ​System​ ​Requirements - Continuity - 3​ ​dimensional​ ​system - Almost​ ​always​ ​aligned​ ​with​ ​the​ ​insulation​ ​layer - A​ ​secondary​ ​air​ ​barrier​ ​can​ ​help - Strength - Wind​ ​loads​ ​and​ ​other​ ​pressures​ ​must​ ​be​ ​fully​ ​transferred​ ​to​ ​the​ ​structural​ ​system - Durability - Will​ ​it​ ​shrink,​ ​shift,​ ​rot,​ ​become​ ​brittle? - Stiffness - With​ ​good​ ​adhesion,​ ​strength​ ​and​ ​durability,​ ​stiffness​ ​is​ ​optional - Impermeability Vapor​ ​Barriers​ ​vs​ ​Air​ ​Barriers - Vapor​ ​barriers​ ​are​ ​not​ ​necessarily​ ​air​ ​barriers - Air​ ​barriers​ ​are​ ​not​ ​necessarily​ ​vapor​ ​barriers Fiberglass​ ​Insulation Pros: - Cheap - Available - New​ ​high​ ​density​ ​fiberglass​ ​blown​ ​in​ ​batts​ ​are​ ​air​ ​flow​ ​retarders - Now​ ​available​ ​with​ ​much​ ​less​ ​formaldehyde​ ​than​ ​before - Cheap - Available - Non​ ​combustible​ ​material…​ ​exept​ ​when​ ​it​ ​gets​ ​really​ ​hot Cons: - High​ ​embodied​ ​energy What​ ​do​ ​Foundations​ ​Do? - Hold​ ​building​ ​up - Keep​ ​groundwater​ ​out - Keep​ ​soil​ ​gas​ ​out - Keep​ ​wind​ ​out - Keep​ ​water​ ​vapor​ ​out - Allow​ ​water​ ​and​ ​water​ ​vapor​ ​out​ ​if​ ​it​ ​gets​ ​inside - Keep​ ​the​ ​heat​ ​in​ ​during​ ​the​ ​winter - Keep​ ​heat​ ​out​ ​during​ ​summer November​ ​15,​ ​2016 Heating​ ​Systems Maxims - The​ ​smaller​ ​the​ ​heating​ ​load​ ​the​ ​smaller​ ​(and​ ​cheaper)​ ​the​ ​heating​ ​system - Air​ ​seal​ ​and​ ​insulate​ ​to​ ​the​ ​max​ ​first,​ ​then​ ​size​ ​the​ ​heating​ ​system - Minimize​ ​the​ ​thermal​ ​lift - Pipes​ ​and​ ​ducts​ ​should​ ​be​ ​short,​ ​fat,​ ​and​ ​straight - Distribution​ ​systems​ ​should​ ​be​ ​responsive​ ​and​ ​low​ ​temperature​ ​(usually​ ​this​ ​means​ ​large) Types​ ​of​ ​heating​ ​systems: Distribution​ ​type:​ ​forced​ ​hot​ ​air,​ ​forced​ ​hot​ ​water​ ​=​ ​hydronic,​ ​“room​ ​heaters”,​ ​steam Heat​ ​source:​ ​fuel​ ​burning,​ ​heat​ ​pump,​ ​simple​ ​pumped​ ​heat​ ​exchange,​ ​electric​ ​resistance Furnaces​ ​Heat​ ​Air - Burns​ ​a​ ​fuel​ ​or​ ​uses​ ​electricity​ ​to​ ​produce​ ​heat - Transfers​ ​heat​ ​to​ ​air - Uses​ ​a​ ​powerful​ ​blower​ ​(a​ ​big​ ​fan)​ ​and​ ​a​ ​system​ ​of​ ​air​ ​ducts​ ​to​ ​distribute​ ​heat - Even​ ​at​ ​high​ ​efficiency​ ​heat​ ​production,​ ​there​ ​is​ ​a​ ​large​ ​electricity​ ​cost​ ​in​ ​the​ ​distribution system - Often​ ​the​ ​furnace​ ​fan​ ​is​ ​the​ ​largest​ ​electricity​ ​user​ ​in​ ​the​ ​house ...
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  • Fall '16
  • Ben Weil

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Christopher Reinemann
"Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

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What students are saying

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    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

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    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

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    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

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    Dana University of Pennsylvania ‘17, Course Hero Intern

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    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

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    Jill Tulane University ‘16, Course Hero Intern