Tech 1 Test 2

Monthly variations in sunlight

* How many minutes of sunlight do we gain/lose around an equinox? Around 3 minutes Sinusoidal variation in sunlight

Short-wave radiation

Absorbed/reflected by opaque materials, but it is transmitted by translucent or transparent materials (glass) This means a large amount of solar energy passes through most materials used for glazing, the remainder is either reflected or absorbed by the glass Objects within the glazed area absorb a portion of the short-wave radiation and convert it to thermal energy which in turn radiates, in the form of long wave radiation, called heat

Analemma

Because of the tilt of the earth on its axis, the position of the sun in the sky changes from day to day throughout the year Sun moving on path of analemma, shape of a figure 8

ice-dams

Ceiling insulation extended Ventilate - soffit has perforations that allow air to move through Eve compression Space saver allows extra lift Solution Better attic insulation and ventilation Raised truss heels: avoid eve compression Attic ventilation - Moore Vents/Baffles Maxi moves air out of attic space Soffit and facia: 3 methods Ridge vents (alternative 1) Rain screens Function of wall assembly Keep rain and water out Control hot/cold air Vapour control Thermal control Maxi vents and roof aerator (alternative 2) Building Code: 1ft2 of roof ventilation for every 300ft2 of roof. Good ventilation is essential to making shingles last. Unvented roof

Calculation of window overhang dimensions

Design overhang to shade side of house α determined from sun path chart design from sun directly overhead Assume that we have already determined the solar altitude angle α, from figure 104 we find that the relationship between the glazing height H and overhang length L is: Tan(90- α) = L/H L = H x tan(90- α) As both H and α are known, we can calculate the length of the overhang by substituting these known values Note: Sometimes this equation is written as: tan(α)=H/L since tan(90 − α)=1/tan(α)

Long-wave radiation

Doesn't pass through glazing as readily as short-wave radiation Much of it stays inside the glazed area as heat, known as greenhouse effect Solar home relies on greenhouse effect for heat collection Using south-facing glazing to admit sunlight, and dark-coloured walls or floors to absorb and transform the sunlight into heat energy Glazing is responsible for the heat gain and light levels in your house

4 potential coating surfaces

First surface is an exterior coating - faces outdoors, never has low-e coating due to exposure to outside elements Second and third surfaces face each other inside IG and are separated by an air space and an insulating spacer Fourth surface faces directly inside

advantages of green roofs

Food production: growth of fruits, vegetables, flowers, turning otherwise hostile environment of concrete and asphalt into viable agricultural land Reduced energy use: reduce insolation, absorb heat and act as insulators, reducing heat transfer through the roof and improving indoor comfort Reduced heat island effect: provide shade and remove heat from the air through evapotranspiration, reducing the temperature of the roof surface and surrounding air Reduced air pollution: and greenhouse gas emissions, by lowering air conditioning demand, vegetation can also remove air pollutants and greenhouse gas emissions through dry particle deposition and carbon sequestration storage Enhanced storm-water management and water quality: reduce the overall volume of storm-water form 64%-94% and slow the peak flow rate of runoff in the urban environment, help filter pollutants from rainfall and used for water purification and treatment Improved quality of life: provide aesthetic relief in urban centers, provide valuable habitat for a variety of animals and insects, reduce sound transmission, and increase comfort Longevity of materials: expected to increase a roof's life-span by 2-3x due to reduction in extremes in temperature and exposure Living walls: aka green facades, bio-walls or vertical gardens, many of same advantages as green roofs, may also be means of water re-use, grey-water treatment, air purification, urban agriculture Plant species Habitat

Passive solar challenges

Importance of orientation: If the largest surface area if >45° off south axis, building can't collect sufficient passive solar gains Big issue in modern developments: pay by the linear foot for land access to roads. Also, taxes often determine by frontage Passivehaus might be a good alternative if you can't get good solar access: Requires heavily insulated walls, building is very air-tight (<0.6 ACH at 50Pa) Warning: These are expensive buildings. Require imported 'certified' materials from Europe Industry direction: Net-zero energy 'ready' Target is around 2030 that all new homes in Canada will be net-zero energy ready Shares all commonalities with net-zero energy except for the PV panels. The thought is that these can be added at a later time which is bad PV integration!!

Low-slope roof finishes

Insulation options Remove shingles before adding new ones Water protection Most expensive Tesla going for this look Parapet: piece of wall extending from the roof *know ice dams Common issue in residential homes in cold climates Roof insulation not extended over wall - weak point Long icicles indicate lack of insulation Note importance of drip-edges

Batt-insulation

Mineral/Stone Wool (Roxul, etc.) (second best) insulation is a rock-based mineral fiber insulation comprised of Basalt rock (volcanic) and Recycled Slag (by-product of steel industry) Advantages: inorganic (no mold issues), fire protection, less air movement than glass fiber Disadvantages: Expensive and high embodied energy (x20 cellulose insulation), poor air sealing compare to spray foams Glass-Wool/Fiberglass: spun from glass into fibers Advantages: inorganic (no mold issues). Can be installed in a batt or blown-in Disadvantages: high embodied energy (x30 cellulose insulation), relatively poor insulation qualities, no air-sealing properties (air passes through easily) Cellulose (best) Cellulose materials include newspaper, cardboard, cotton, straw, denim, sawdust, hemp, corncob, and a fire retardant Advantages: Low cost, has some air-sealing properties (not as good as spray-foam), higher R-value than fiberglass, low embodied energy, natural product (fire-retardant borate is a salt, 20% of final product) Disadvantages: can settle over time (needs to be densely packed/blown-in), can't get wet (water intrusion can separate newpaper and fire-retardant) Cellulose blown-in installation (loose-pack) Cellulose has a fire retardant added that (borate and sulphates/salts)

Passive solar: old vs new way

Old: Rules of thumb (1980s and 90s) Based largely on experience (estimates from previous successes) Ex. "The Solar House" by Daniel Chiras New: Quantify using first principles (2000s) Numerical analysis which takes building and site into consideration Ex. option X is 15% better than option Y

New material: vacuum insulation panels (VIP)

PIR is Polyisocyanurate rigid spray foam Vacuum Insulation Panels (VIPs) are ultra-thin, high-performing insulants that can be up to 20 times more effective than traditional insulation products. A VIP consists of a rigid core material encased in a thin, gas-tight outer envelope, which is evacuated and sealed to prevent outside gases from entering the panel. Note: 0.16 W/m2K = R-36 = 6.25 RSI

spray-foam

Polyurethane High density 2 pound/ft3. Non-water permeable or "Closed-cell". R-6.5/inch High density 1 pound/ft3. Non-water permeable or "Closed-cell". R-5.6/inch Low density ½ pound/ft3. Water permeable or "Open-cell". R-3.4/inch. Cheaper than 2lb Icynene: Available in both open and closed cell options High density 2 pound/ft3. Non-water permeable or "Closed-cell". R-6.0/inch Low density ½ pound/ft3. Water permeable or "Open-cell". R-3.7/inch. Cheaper than 2lb Advantages: High R-value, water-seals, air-seals AND insulates Disadvantages: some have off-gassing issues (Formaldehyde), flammable (petroleum-based), expensive, temperature in roof cavity over 120C at 200C will self-ignite Open or closed (air, thermal, and moisture barrier, studs weak point) cell - how moisture moves through Different densities (2 pound highest, 1 or ½ pound) Different mixtures (water-based)

Wind shelters

Provide wind breaks using trees Unprotected buildings use more energy "military crest" where buildings placed on hill Strong winds increase infiltration of air into house and accelerate the conduction of heat through glazing and walls, the potential for heat loss on a cold windy day is much greater than on a calm day Defend against cold winds by retaining lots of tree cover on the north side of the house Trees will break the force of the wind or deflect it over the house, reducing heat loss No tree cover, you can plant a windbreak that will need to be established for a few years Windbreaks must extend past the width of the house to be effective (more rows of trees also more effective) Use one directional summer winds to your advantage Channeling summer breezes through trees or around berms can keep house cool Take advantage of natural ventilation and cooling in the summer by placing windows or vents in strategic areas Cold air falls and warm air rises, why low-lying areas tend to get early frosts Avoid placing house on depressing site or in area that does not get sun until late in the day

Exterior rigid foam

Rigid insulation helps break thermal bridging of studs. 1" is easy to add to a wall assembly. 1.5 to 2"s requires careful considering of how to sit windows in the wall

greenhouse effect

Short-wave radiation from the sun passes through glass to warm the surface of objects inside a space The long-wave radiation from the warmed surfaces does not pass through the glass easily, so most of the radiant heat stays in the space Heat loss is due to conduction

New material: aerogel insulation

Silica based aerogels have very high R-values/inch (R-10 to R-20 per inch). Originally applied to space capsules, it is slowly finding traction in the construction industry. It is made up of a gel that has had its liquid component replaced by air — in fact the material is 99% air. Aerogels are thin, breathable, fireproof, and don't absorb water. There are several other variants such as aerographite and aerographene.

Passive solar design and building metabolism

Solar: Use sun for heating (when you have heating demands) Up to 50% of a buildings heating demand can be offset (Ottawa) Shading: Avoid sun when it results in cooling Ventilation: Use outdoor air when at a appropriate temperature for heating/cooling Daylight: Better to use daylight than artificial light Glazing: Want the right-size of windows (<50% WWR) and appropriate glazing properties Thermal Mass Store excess heat for use when you need it. Ex. Winter: Afternoon sun used to offset night heating Passive solar design requires systems-level thinking where one design aspect must be balanced with another. Models can be an effective method to inform decision making on design choices and fine tune passive solar aspects of a design. But BEWARE: Creating accurate passive solar models takes years of training and experience Still the basic principles apply: build tight, ventilate right insulate well and avoid thermal bridging NOTE: Although this lecture emphasizes PV, using the sun directly is VERY efficient for solar heating. Can get almost 80% of sun hitting a vertical wall into the living space Passive solar guidelines Use the sun: Orientate largest surface area south Percent of solar heat gains using 15° increments. Outcome: OK if you orientate a building ± 30°! Use the wind (able to provide fresh air AND free cooling) Use thermal mass Thermal mass: large amounts of interior thermal mass are characteristic of passive solar architecture in temperate climate zones. Mean radiant temperature is more effective than air temperature in providing comfort Concentrated thermal mass (C): allows for the greatest amount of thermal mass radiatively coupled to the sun it it is an outside, equator facing wall with glazing. It usually consists of water or thick masonry although advances in phase change material offers additional opportunities Distributed thermal mass (D): spread over a greater area of the building's interior. It has a large surface area and although some may be radiatively coupled it is largely coupled to solar heat or cool air by convection Better to avoid air-conditioning by using effective shading Better to avoid electrical lighting by having a daylighting strategy Avoid large glazing surfaces on west walls

Solstice ("sun stand still")

Summer: June 21 - tilting towards the sun Winter: December 21 - tilting away from the sun

Natural ventilation

Use outdoor air to naturally cool building Consider openings (where, how long) "Cross-ventilation" to naturally ventilate building "Stack effect" to naturally ventilate building Issue of pollutants (make sure no vents are open where people are occupying the space) - harder in dense urban environment

Equinox ("Equal Night")

Vernal (spring): March 20 Autumnal (fall): September 22

jet stream and micro-climate

What's with the unusual weather? Why do we alternate between the cold winters and warm summers? When the poles are cold and equator is warm, there is a strong jet stream which holds weather systems in place However, the poles are heating up faster than the equator due to man-drive (anthropogenic) global warming This causes cold (low pressure) systems to meander further down south and break off from the jet stream. This is the cause of major storm systems such as Snowmageddon. Interesting to note that Rossby waves typically alternate on an annual basis. This partially explains why Europe and North America alternate between record droughts and record floods.

How much electricity would a 50m2 surface covered in PV panels generate in one year? Given: Angle is 45deg (1250kWh/kW) Location is Ottawa Panel is Canadian Solar CS6P-260P (16% efficient, 260W, 1638 x 982mm or 1.608516 panels/m2)

step 1: How many panels (assume a perfect fit) N = 50/1.608516 = 31 step 2: calculate the power output for 31 panels P = 260 × 31 = 8.06kW step 3: calculate the electricity produced E = 8.06kW × 1250kWh/kW = 10, 075kWh

Disadvantages of wood light frame

- Burns easily ("box of tinders") and rapidly - Responds to changes in humidity (warps and bends) - Unattractive (seldom left exposed in a building) - Decays if exposed to dampness

balloon framing

- Came before platform framing (earliest wood framing system) - Joists for floors, rafters for sloping roofs, studs for walls - Heavy posts and beams eliminated - 40% less money than mortise and tenon frame - Full length studs that ran continuously for 2 stories (foundation to roof) - too long to erect efficiently - Advantage: quicker to erect structure - Disadvantage: need long continuous spans of material, tall and hollow spaces between studs acted as multiple chimneys in a fire that would spread blaze rapidly unless closed off by fireblocking at each floor line

Exterior Surfaces: Things to Consider

- Does the exterior finish have a function? - More often than not, exterior surfaces are for aesthetics (and to protect inner layers) - Notable exceptions: ventilated cavities such as brick, stone (act as rain screens) - How does the material react where there is a problem o Some surfaces age well and show problems when they happen Brick will laminate and or crumble Wood rots before serious problems occur in the wall o Other surfaces hide issues: Vinyl will only show issues if shape is distorted Metal/Corrugated steel hides all!

Wind utilization (movement across a site)

- Global circulation - jet stream and micro-climate - wind shelters - natural ventilation - turbulence -

Moisture Movement

- Liquid Flow o Cold climate (heating dominated) Warm moist air inside, through wall, to outside o Hot climate (cooling dominated) Vapour barrier on o Wall paper and vapour barrier (only want 1 barrier) - Capillary suction o Fully adhered membrane o First 3 barrier, no thermal insulation o Vapour barrier towards exterior of envelope - Air movement - Vapour Diffusion - How do I know when the water will condense? o Water condenses when the air-temperature reaches the wet-bulb temperature. Typically know relative humidity (percentage of water vapour relative to the maximum amount that air can hold) and dry-bulb temperature. o Psychrometric Chart: Know any two properties of air, can determine everything else. FYI only - What is BlueSkin? 1. Rain/Water control layer? 2. Air control layer? 3. Vapour control layer? 4. Thermal control layer (insulation)? o Combination of 1, 2, and 3 (negligible insulation)

Advantages of wood light frame

- Minimal tools required, build with hand tools - Extremely flexible: can build any shape - Resisted manufacturing approaches (for now) - Cheap (labour and materials), strong labour force - Most versatile of all building systems - Small residential and commercial buildings

Solar Photovoltaics Panels (PV)

- Now 30cents/Watt panel cost (approaching $1/W installed) - Cheaper than grid power o 2016 Lowest bid on solar was now 2.9 cents/kWh o Considered the tipping point at which no other form of energy generation can compete with PV. We are well ahead of schedule to achieve in 2017 what was thought it was going to take till 2025 - What is good/bad solar integration - If solar is cheaper than fossil fuels, fossil fuels are over - Experience curve = amount of product made dictates price - Fossil fuels using PC to extract oil - Efficiency of panels increases (25% efficiency) - Thin films o Thin layer (microns thick) less substrate decreases cost o Projected to be more efficient than silicon - Maximum efficiency 90% if collect all waves of sun (closer to 40-50%) - Cheaper and more efficient

framing variations

- double stud - staggered stud - advanced framing

types of PV inverters

- micro-inverters (distributed) - string-inverter (centralized)

Types of Fasteners

- nail types and sizes diagrams - Nailing tools: guns o Advantages of portable nailing guns: solve many issues with compressed air nail guns, no need to carry compressors up on roofs, reduced maintenance (less moving parts, moisture protection with compressors), some additional cost but this will likely equalize over time - Nail finishes o Uncoated called "bright" o Box coat (more holding power) Nails hold well under shear Note: screws don't hold well under shear o Galvanized: outdoor use/corrosion resistant o Stainless steel: best corrosion protection, highest cost - Screw types - Screws vs nails o Screws hold well under tension, brittle under shear o Nails hold well under shear, hold less well under tension ("pull")

Roof Finish Options

- shingles - tin roof (drip edge) - copper roof - metal roof shingles (Parliament) - cedar shakes (most common) - slate shingles

Insulation types

- spray-foam (polyurethane, icyene) - batt-insulation (Mineral/Stone Wool, Glass-Wool/Fiberglass , Cellulose)

Site Planning

- storm water management - Wind utilization (movement across a site) - Passive solar and building metabolism

platform framing

1. Floor platform is built 2. Loadbearing walls built upon it 3. Second-floor platform is built upon walls 4. Second set of walls upon this platform 5. Attic and roof built upon second set of walls - Universal standard for wood light frame construction - Wood studs interrupted by floor (non-continuous) - Advantages: easier to handle, shorter pieces (less cost), fire-blocking provided by platform - Disadvantages: vertical shrinkage/swell in the frame causes damage and stress to exterior/interior finishes (due to horizontal grain orientation of each platform), fire issue if block not added in wall

Functional Control Layers in an Enclosure

1. Rain/Water control layer 2. Air control layer 3. Vapour control layer 4. Thermal control layer (insulation) o *Prefer continuity of all layers*

Factors of good window design

1. The type of glazing material (e.g., glass, suspended film, treated glass) 2. The number of air chambers created by multiple layers of suspended film or glass panes 3. What type of gas, if any, is used to fill the air space(s) 4. The thermal resistance of the frame and spacer materials 5. The "tightness" of the window - how much air leaks through o (Common test question. Used to determine if you understand the important characteristics of window performance. May ask which of the following is not a important factor in window design)

steps in residential construction

1. excavation 2. footings and foundation walls 3. Floor Over Foundation Wall 4. wall framing 5. beams, joists, and floors 6. walls and stairs 7. trusses and roof framing 8. roofs

framing techniques

1. platform framing 2. balloon framing

Total Heat Transfer

All three modes of heat transfer occur at the same time! However, some modes can be more dominant qtot = qcond + qconv + qrad (W/m2) - Raises temperature profile (surface) - *differentiate between convective and radiative heat transfer - * parallel wall

R-value notation

Insulation materials are commonly described in terms of the so-called R-value (thermal resistance) In metric units, it is commonly referred to "RSI" or R-value System International 1 RSI = 1 (K∙m2)/W Note: resistance sometimes written as U-value where U = 1/R In the imperial system, it is simply called R-value R-1 = 1.00R¬imp = 1 (F∙ft2)/(Btu/h) Useful conversion factor (imperial to SI): 1RSI = 5.678 Rimp * know conversion factor Thus, R-1 (imperial R-value) is short form for: 1 (F∙ft2)/(Btu/h) R-20 = 20 (F∙ft2)/(Btu/h) = 1 20/5.678 (K∙m2)/(Btu/hW) = 3.52 RSI (see notes for examples)

Solar control low-e coating (soft coat)

MSVD process, coating applied offline to pre-cut glass, sealed in I-G or laminated unit, has lower emissivity and superior solar control, best performing solar control coatings are MSVD, ideal for mild to hot climates that are dominated by ac use

Conductive heat transfer through multi-layer materials

Rtot = RA + (RB∙RC)/(RB+RC) +RD Rtot = RA + Req + RD Commit to memory: Req = (RB∙RC)/(RB+RC) o Other alternative method is called the parallel path method o Isothermal method tends to underestimate effective R-value o Best used when R-values are dissimilar o Parallel path method works better for similar R-values o Thermal bridge o Lower R-value limiting factor o Use multiplicative formula when elements are in parallel (each layer beside the other)

Conductive heat transfer through two-layer materials (isothermal method)

Rtot = RA+RD o Additive in series o Use additive formula when elements are in series (one layer directly after the other)

sheathing

a facing layer of boards or panels that join and stabilize the pieces into a single structural unit

emissivity

a measure of the effectiveness of a material in absorbing and emitting energy as thermal radiation (long-wave radiation). Emissivity, symbol ϵ, ranges from 0 to 1. An object which perfectly absorbs and re-radiates thermal energy is a called a black-body (ϵ = 1).

BIPV

a photovoltaic generating component which forms an integral and essential part of a permanent building structure without which a non-BIPV building material or component would be required to replace it o The performance of power generation by a BIPV component is deemed to be secondary to the role of being a building material or structural component o BIPV occupies a space in the building design such that, if removed from that space, its absence will be distinct and noticeable

PV performance tests

flash test o Controlled environment o Set temperature o Set atmospheric pressure o How they are rated o Measure efficiency

Solar Heat Gain Coefficient

fraction of incident solar radiation admitted through a window, both directly transmitted and absorbed and subsequently released inward. The lower a window's solar heat gain coefficient, the less solar heat it transmits (infrared, visible and ultraviolet) It is expressed as a number between 0 and 1 1: all solar radiation gets through 0: no solar radiation gets through Note: the heat transfer through a window can be written as qwin = Gsun SHGC + Uwin ∆T, units W/m2 Gsun : the solar irradiance hitting a window Uwin (W/m2): the windows U-value ∆T: temperature difference across the window (warm-cold)

headers and trimmers

frame openings in floors and roofs

Windows: cut-out

glazing and thermal spacers o 3 panes of glass o Fill: clear, noble gasses (non-interactive) o Spacers: ceramics reduce heat transfer, thermal break, low heat conducting materials o Pane

sills

head off the bottoms of window and door openings

solar constant

how much energy do we receive from the sun? o Amount of sunlight hitting earth atmosphere o Varies on 11 year cycles o Reflection, absorption - balance of solar energy hitting the Earth (staying as heat or reflecting back) o Solar constant: Gsc = 1367W/m² Energy from sun per unit of time per unit area o Variations are caused by some unknown nuclear process in the Sun

Micro-inverters (distributed)

inverters on back of every panel, use when panels will be partially shaded

Passive low-e coating (hard coat)

manufactured using pyrolytic process, coating is applied to glass ribbon while it is being produced on float line, coating fuses on hot glass surface, creating strong bond or hard coat that is durable during fabrication, glass is cut into sheets of various sizes, good for cold climates (allow some of suns short wave infrared to pass through and heat during winter but reflect interior long wave back inside)

Visible light transmittance (VT)

measure of how much light passes through a window, commonly used for daylighting studies

direct radiation

most intense, largest amount of radiation we receive on a clear day

reflected radiation

most prominent on a clear day and requires a surface (like snow cover) to reflect (rather than absorb) some of the direct radiation incident on the surface

toenail approach

nailing approach from both sides, strong, can't pull wood stud out with 2 (see diagram, lecture 4)

Purpose of Building Wrap

o "A flashspun, high-density polyethylene fibers which allows water vapor to pass through, but not liquid water" o Allows envelope to breath/dry while keeping addition water from getting in o Patent owned by Dupont o Also has some air-sealing properties o Improvement over tar-paper (previously used) - Moisture barrier (lets moisture through in one direction) - Vapor passes through, not water - Same properties if inversed (not directional) - Allows wall systems to breath - Goes underneath siding

advanced framing

o *draw load path diagram o Studs further spaced apart o Redundant framing members eliminated o Total length of framing lumber used is half that required for wall o Advantages: saved material (reduce waste), less heat loss, save money, improve energy efficiency o Disadvantages: inflexible (dangerous to move a wall), you can't visualize how it is built, don't know how loads are carried

Solar Ready

o A Solar ready home enables owners to add solar panels or solar hot-water after construction o Done by carefully running vertical chases/conduits from the roof to mechanical rooms (typically in basement) o Pipes and wires can easily be run without major construction o Solar ready homes are now transition to net-zero energy ready homes. Goal is to make PV easy to install post-construction

Vapour barrier

o A vapour barrier is any material used for damp proofing, typically a plastic or foil sheet, that resists diffusion of moisture through wall, ceiling and floor assemblies of buildings to prevent condensation. o A perm measures a materials resistance to moisture diffusion. The SI measure is the nanogram per second per square meter per pascal. The lower the perm the less the moisture transfer. o No such thing as 100% effective vapour barrier. o Do you really need a vapour barrier? Ex. Passive house consultants may recommend not having a vapour barrier at all. Additional analysis are required to say definitively yes or no Important that the wall never exceeds 80% relative humidity for an extended period of time. Tools to conduct a moisture analysis: WUFI Combine barrier into 1 surface Move to exterior of structure All insulation on exterior Keep rain off wall (brick used as rain screen) If heavy rain happens, brick absorb water, saturate brick Cavity is breathable, keeps rain from getting on surface o Joints need to be taped using acoustic sealant or duct tape for a continuous barrier o Building sealants Acoustic Sealant: help seal overlaps on vapour barrier. Seal cracks PL Premium: Glue wood members Caulking: Seal cracks in windows, doors, etc.

staggered stud

o Alternating stud members o Fully insulated cavity

solar radiation

o Amount of radiation from the sun that reaches your house and is captured by glazing, solar thermal collectors, or a PV array o The amount of solar radiation that reaches the Earth is affected by atmosphere and cloud cover o Incoming radiation broken into direct, diffuse and reflected components o Whether an opaque surface absorbs or reflects short wave radiation is dependent on the colour and texture of the surface itself o Radiation absorbed by a material is converted into thermal energy (called heat)

Passive solar and building metabolism

o Building metabolism is a helpful differentiation to keep in mind between a larger building's and smaller ones o Analogy is the elephant and the humming bird: Elephant: more thermal storage, larger volume compared to surface area, ∴ smaller mechanical systems relative to gross floor area Hummingbird: larger surface area with respect to volume, heat loss through walls dominates energy balance.

Passive solar design

o Collect sun for heating o Most of the sun's energy in visible range o Sun comes in as visible light, hits surface (a coating), turns to infrared and reflects - passive windows o Put coating on outside to help keep building cool o * does sun every hit North surface - yes, but just a fraction of the year No solar panels on North face of building, avoid glazing on west face

advantages of light gauge steel construction

o Convenience Lighter than wood, takes up half the space of lumber due to hollowed shape Easier transporting and storage Cut metal studs with snips, which means no sawdust o Ease of installation Easier to handle because studs weigh a third less than wood and can be installed at 24" on center Also attached with screws, so moving studs is simple if mistake is made o Stability Wood prone to twisting and warping; metal is not Wood also wicks moisture, which can lead to mold growth and rot, while metal is immune Metal does rust, so install a vapor barrier or sill gasket between bottom plate and concrete floor o Strength Ideal for construction in high-wind and seismic zones Better strength per weight than wood o Insects and fire Carpenter ants and termites can severely damage wood construction, but not metal Wood burns and metal does not Wall built with metal studs makes it more difficult for fire starts however steel buckles with high temp o Construction cost Steel framing can cost 3-15% more than wood studs Metal studs offer cost advantages in other areas that can offset this price difference Warranty call-backs minimized because steel does not shrink, split, or warp No nail pops or drywall cracks to fix after structure is completed o Sustainability Steel is recyclable

Low-emissivity coatings

o Depends on climate o Reflects infrared heat o Coating on glazing - solar ban windows o Actually, the above equation is an approximation o Radiative heat transfer obeys the Stephan-Boltzmann law. q = ϵσT4 o Where q is W/m2, ϵ is unitless, T in Kelvin, and σ is the Stephan-Boltzmann constant It turns out that we can approximate T4 ~= (T2-T1) when temperature differences are small o For the control of infra-red heat (long-wave radiation), it is desirable to limit the amount of radiative heat gains through reflection. Objects which reflect thermal radiation well are said to have a low-emissivity or short-form low-e. Typical low-e coatings have values of ϵ= 0.05-0.28. Low-e coatings were a major advancement in window technology during the 80s and 90s. o Note: all materials have properties for transmitting (τ), reflecting (ρ), or absorbing (α), radiation with a constraint that τ + ρ + α = 1. o Back bodies are perfect absorbers meaning that: ρ = τ = 0, thus α = 1. Perfect black bodies are theoretical tools and don't actually exist in nature.

Vinyl/aluminum/fibercement siding

o Fiber cement averages about $1.70 per square foot and is practically indestructible. Sources: SPG Marketing, R. S. Means, National Home Improvement Estimator o Wood: Prized by traditionalists, it's lightweight and easy to cut and work but vulnerable to rot, insects, fire, and splitting. Individual shingles are time-consuming to install and maintain. Expensive. o Vinyl: Low-maintenance and lightweight, it melts in fires and can easily blow off in high winds. Comes in textures but doesn't replicate wood siding as well as fiber cement. 75 cents per square foot. o Aluminum: won't rot or burn, and is easy to maintain. Dents easily and is difficult to repair. Clapboards average about $3 per square foot. o Stucco: Averages about $2.65 per square foot.

Window installation options

o Fin: plastic flange o Integrated fins (match exterior insulation) o Block frame: no flange o Space between frame and window 3/8", more space = more fill o Movement causes cracks in the frames

Building integrated PV

o Heat management strategy to avoid heat degradation of panels o Panels are roof surface o Decrease price (no longer have to shingle) o Increase lifetime of panels (take heat off panels and use it for heating) o Solar wall o Testing BIPV - solar simulator

solar radiation and buildings

o Key points in good passive solar design for cold climates are to maximize solar gain and minimize heat loss in the winter, and, to minimize the solar gain and maximize cooling in the summer o Glazing responsible for solar gain in home and heat loss (glass is poor insulation material and conducts heat readily) o Heat loss reduced by installing low-e, double paned glazing in your house o Low-e glass enhances the greenhouse effect by blocking passage of the long wave radiation and conductive heat through the glass o Heat loss through conduction is also reduced by double paned glass The airspace between the two panes acts as an insulator, blocking the flow of heat through the window

Latitude vs Longitude

o Latitude: angle from equator to pole - dictator of when sun rises, how much solar exposure, largely determines intensity and duration of solar radiation

- Disadvantages of light gauge steel construction

o Less familiar technology o Requires a different set of tools o Issues with rust o More susceptible to thermal bridging, steel conducts heat 400x better than wood o Material cost is higher o Non-renewable resource (higher embodied energy if not recycled)

building wrap and air leakage

o Most common measurement on a house o The air-leakage rate determines how tight a building envelope is. Typically, air-tightness is described using (Air-Changes per Hour (ACH). 1 ACH defined as the entire volume of a building being changed over in one hour. o ACH can be described at atmospheric pressure or by depressurizing/pressurizing the building (typically to 50Pa, denoted as ACH50Pa). 50Pa of depressurization is roughly similar to the air-flow by opening a subway/metro door. o Buildings are pressurized/depressurized using a Blower-door. Air-tight buildings will have an air-tightness of <1ACH50Pa o Decreased ACH = decreased energy use o No chimney improve air tightness path, headers common air leakage path o Blower-door test Air-tightness measurements are most accurate if conducted by pressurizing and depressurizing. The estimated air-tightness is the average of both measurements. Both directions depending on location (not Canada) Blower-door data from Canada Average home is around 5ACH at 50Pa PassiveHaus: 0.6 ACH at 50Pa Net-zero energy is possible a <1.5ACH @50Pa Long tail Some external force of distribution

Heat balance

o Radiation -absorbed fractions + reflected fraction + transmitted fraction = 1.0 o Convection - becomes significant if a thermal spacer malfunctions (condensation between glazings) o Condensation = failed spacer (seal between glazings compromised)

Estimating annual PV Yield (Ottawa, 16% monocrystalline PV)

o Rough estimate of how much energy home will produce o Calculate how many kW of panels o Determine where panels are located o kWh/kW: Energy generated per year (kWh) per panel power rate (kW) o Performance (kWh/kW): Flat: 1100 kWh/kW 45deg Slope: 1250 kWh/kW (Note: Slope = Latitude) South Vertical: 870 kWh/kW East Vertical: 700 kWh/kW West Vertical: 700 kWh/kW o For Canadian Solar CS6P-260P: 260W/panel (flash test) Panel dimensions 1638 x 982 x 40mm Therefore: 161.64 W/m2 o DON'T USE FOR OTHER PANELS! o Now you can calculate PV yields (kWh) from roof areas o Round down

Solar radiation on sloped surfaces: solar noon

o Solar resources given on horizontal but at an angle o Determine where sun is in sky, azimuth o Shorizontal = Sincident × sin(α) o Smodule = Sincident × sin(α + β) o Smodule = Shorizontal × sin(α + β)/sin(α) o NOTE: β is panel tilt, solar altitude: α = 90 − Lat + δ o Optimal PV Placement for max Generation: angle ~= latitude o Often solar radiation is reported on the horizontal plane. Additional calculations are required to get the solar radiation on a sloped surface (called the incident radiation). o Confused by α = 90 − Lat + δ? o Angle between horizon and sun is α. Know 90 − Lat = α − δ (see diagram below). Then solve for α

Center of Glass U-Value: Effect of good spacers

o The window on the left is a double glazing with low-E and an insulating spacer. The window on the right is a quadruple pane design with a gas fill of krypton instead of air (better) but has a poorly performing spacer. These windows are being cooled on the back side with wind at -17.8°C (0°F). Image from Lawrence Berkeley National Laboratory o Weak point with many glazing side by side

double stud

o To fit more insulation o Breaks thermal bridges o Takes up a lot of space

Window frame options

o Vinyl: low-cost, bestseller in America, welded corner (not aesthetically pleasing), not paintable, not as strong (issue in heat) o Fiberglass: best value, crisp details, thinner, o Composite: some vinyl mixed with wood fibers, not as strong as fiberglass o Fiberglass frame with wood cladding: looks traditional, lower cost o Aluminum: make sure it has thermal break (plastic spacer) separates outside aluminum from inside aluminum, spacer keeps two layers away from each other o Wood: traditional inside, outside bonded to aluminum outside skin (typically painted), factory finish, long lasting, good thermal performance, costly

storm water management

o Water permeable pavers o Store pavement water, treating it and returning to environment o Living walls Improve air quality Breakdown volatile organic compounds Cooling effect o Green roofs Not improved R-value Storm-water feature (some water retention and dissipation)

Sun path diagrams

o Where sun hits building, at what angle o Sun lowest winter solstice, highest at summer o Dictate angle based on date o Want extremes (highest/lowest) when designing o Average times o Azimuth: angle of sun with respect to orientation (south is 0) o Altitude: angle of sun off horizon o Sun path diagrams for different latitudes (polar)

ridge board

provided at the roof peak (in a sloping roof the wall top plates play a role of the lower crosspiece)

Convection heat transfer

qconv hc ∆T = hc (T1 - T2) where: hc : convective heat transfer coefficient (hc = 4 - 18W/m2 K) qconv : the convective heat transfer, units (W/m2) T: the temperature difference between the warm surface and cool air Second mechanism for heat moving through a building Temperature profile of wall facing sun hotter than outside Convective current Larger hc = larger heat transfer

Radiative Heat Transfer

qrad hr ∆T = hr (Thot - Tcold) where hr : radiative heat transfer coefficient (hr = 4 - 12W/m2 K) - 4-12 is a range (not subtracting) qrad : the radiative heat transfer, units (W/m2) T: the temperature difference between the hold and cold surfaces Radiative heat transfer is less emphasized in this course Temperature surfaces have a gap in between Actually, the above equation is an approximation Radiative heat transfer obeys the Stephan-Boltzmann law. q = ϵσT4 Where q is W/m2, ϵ is unitless, T in Kelvin, and σ is the Stephan-Boltzmann constant. It turns out that we can approximate T4 ≈ C ⋅ (T2 − T1) when temperature differences are small (C is a constant) Radiation is the only mode of heat transfer that can occur in a vacuum. This is why we feel warmth from the Sun!

Fourier's Law of Conduction

q¬cond = k∙dT/dx units (W/m2) q¬cond : the conductive heat transfer through the material k : the conductivity of the material, units W/(m∙K) q¬cond ≈ ΔT/(Δx/k) = ΔT/R = ((Thot-Tcold))/R x : the thickness of the material, units meters (m) T: the temperature of the hot and cold surfaces, heat flows from hot to cold, units are Kelvin (K) or centigrade (C) R= x/k is the resistance of the material, units (K∙m2)/W Watt J/s Temperature difference between surfaces divided by R-value (resistance of material) Standardized process to determine R value Conduction independent of thickness (property of material) Typically, we solve for conductive heat transfer by unit area of the material Total heat transfer (Q in Watts) is calculate by multiplying q of the total area where heat loss occurs (Q = q ⋅ Asurface)

U-value

rating given to a window based on how much heat loss it allows

Turbulence

separation of air flow that alternates from one plane to another Design for torsion (resist torsional force) Ideal situation: have continuity, air path If wind speed is greater than 1 m/s, can't naturally ventilate Heat management in attics

overshadowing

shading of a building from obstacles Continuously changing angles of the sun will create shadow regions behind buildings throughout the year. These regions, called shadow prints, are shown in the plan and side elevation. We can determine the outline of the shadow print L = H/tan(α) H- obstruction height L- length of shadow α- solar altitude The shadow print outline is determined by repeating this process for dates, times, and corresponding sun height angles of interest, keeping in mind that L2 is aligned with azimuth angles in the sun path diagram Overshadowing most significant during winter Example overshadowing calculation How far should a building of height (latitude 40˚) be distanced from an object with height H (due south) to avoid overshadowing at noon for the site considered in the given sun path diagram? Consider the extremes in solar altitudes 70 and 20 L(α = 20) = H/tan(α)=H × 2.75 L(α = 70) = H/tan(α)=H × 0.36 Good rule of thumb is to place buildings at a distance 2x the height from the nearest object to avoid overshadowing

subfloor

sheathing applied over the floor framing

Angle of incidence

since the radiation coming to Earth is in essentially parallel rays, surfaces perpendicular to those rays intercept the greatest amount of energy. As the sun's rays move away from being perpendicular, the energy intercepted by a surface decreases.

Excavation

step 1 - Establishing the location of the building on site - Surveyor to distinguish corners and determine setbacks - 3-4-5 method of surveying o Hold a tape at 0m and 12m at a corner, pull the tape tight in two different directions along an axis of interest and you will have a perfectly 90 triangle o Old method

footings and foundation walls

step 2 - Concrete foundation - Weeping tile to take water away from foundation - Backfill with sand - Once formwork is up, fill with concrete - Footings pour first before foundation - Weather proofing (water proof membrane vs damp proof membrane) - Insulation on outside to keep structure dry/warm - Water drainage - Energy conservation codes require foundations to be insulated to reduce exchange of heat with surrounding soil (see examples below) - Basement with exterior insulation o Foam plastic on the outside of foundation walls and under slabs on grade should be avoided where the risk of termite infestation is high o Material can provide concealed pathways for these insects between the ground and the building structure - Basement with interior insulation o When facing the building interior, foam plastic insulation must be covered with gypsum wallboard or some other fire-resistant material so release of toxic gasses from foam plastic is delayed - Crawlspace with interior insulation o simple application of insulation batts to a heated crawlspace is suitable for very mild climate - Crawlspace with natural ventilation o When a crawlspace is ventilated to exterior, floor platform above must be insulated o Rigid insulation underneath the floor joists reduces thermal bridging and protects the joists and batt insulation from high humidity in the crawlspace o Foam plastic must be protected from direct exposure to fire - Slab on grade with exterior insulation o When a slab on grade is connected to foundation wall, insulation must be applied to exterior - Slab on grade with interior insulation o When slab on grade and foundation wall are independent, insulation may be applied directly under and around the edges of the slab - Permanent wood foundations: in extremely cold regions foundations may be made entirely of preservative-treated wood that can be constructed in any weather, readily insulated and easily accommodate installation of electrical wiring, plumbing, interior finish materials - Rough carpentry: building of the platform frame structure

Floor Over Foundation Wall

step 3 - Foundation sill plate: made of preservative-treated wood for resistance to insects and moisture, is attached to the top of the foundation to serve as a base for the wood framing to follow, may be made thicker to create a stronger connection between the foundation and the wood frame above - Sill seal (or sill gasket): made of any of a number of compressible or resilient materials, is inserted between the sill and the foundation to reduce air infiltration through this gap and to restrict moisture wicking up from the foundation into the wood framing - Termite shields: inserted where the risk of termite infestation if high, between the foundation wall and the sill, prevent termites from travelling undetected from cracks in the concrete up into the wood framing - Joists o Metal web joists Mech/eng/plumbing (MEP) prefer open web joists for distributing services o Floor joist runs across, need structural beam o Floor joist different shapes/sizes o Wood I-Joist Commonly used Commonly called "Truss Joist" I-Joist (TJI) Lightweight Span different lengths, determine spacing and size with span charts (30ft) Span charts: ways to look up whether wood will span a certain distance More easily accommodate piping, ductwork, and wiring within the floor platform o How to support joists: moisture break (when concrete touches wood) o Floor truss Span farther than solid wood joists Reduce shrinkage in the floor platform Provide natural openings to accommodate building services Deeper than solid wood joists or I-joists but can span farther (may result in thinner floor/ceiling assembly) o Rim joist vs Floor Joist Rim joist • Way to keep in place at end of foundation wall • Blocking to keep up right • Air leakage paths Floor joist o A strip of compressible foam gasket is placed between the concrete and the sill plate (other options: fibreglass, sand mix) Still plates should not be flush with exterior foundation wall Should leave enough room for sheeting to be applied (want this to be flush) o For a stiff, quiet floor subflooring should be flued to the joists. The adhesive is a thick mastic that is squeezed from a sealant gun o Joist installation Held by joist hangers Takes load off joist, land on beams Pole has to be nailed Web blocking: where a joist hanger is not tall enough to restrain both the top and bottom flanges, inserted on either side of the web to restrain the joist from tipping sideways Bridging and blocking: installed to resist joist overturning or stiffen longer spans Blocking or bridging joists (lateral support) • Chose 1 method • Solid blocking most common • Regular spacing More common to run floor joists all the way on top of a foundation wall o Subflooring: installed after floor framing is complete, Panels laid with longer dimension perpendicular to framing (stiffer in this orientation) Typically has different veneer gradings on either side 1/8" gap maintained around panel edges to prevent buckling (caused by expansion of rain-wetted panels) Adhesive applied to tops of joists to reduce squeaking and increase floor stiffness

wall framing

step 4 - Laid on ground, place members in correct spot - Important to match crowns, typically matched out (ex. Interior) exterior - Headers: span across the top of an opening, take the loads from above the opening and carry them to either side - Jack studs (or trimmers): shortened studs upon which headers rest, nailed to king studs - At the bottom of a window opening, the rough sill is supported on cripple studs - Leakage path between members - *wall with part missing, draw in framing pattern - Imperial - 16" between studs - Advance framing - up to 24" - *what is a proper 3 stud corner, typical and improved methods - Typical corner (left), improved 3-stud corner (middle) and 2-stud (best, right) o What to reduce thermal bridges and still allow room for insulation o Need backing to attack drywall/OSB (think of a drywaller) - Alternative continuous corner - Wind uplift o Isolation system to take out vibration from wall - Lateral force resistance and shear walls o Lateral forces can cause sliding, overturning, or wracking o Sliding at top of foundation is resisted by the anchor bolts and foundation sill plate o Overturning resisted by hold-downs that are installed to prevent structure from lifting off the foundation o Wracking resisted by sheathing or bracing o Shear walls made stronger by lengthening the wall, using thicker structural panels, adding a second panel to the opposite side of the wall, increasing the size of nails used to attach the panels, spacing nails more closely o Openings in shear walls (doors and windows) reduce lateral force resistance

beams, joists, and floors

step 5 - Floor beams: carry load from floor to foundation walls - Options for beams o Engineered: glue-laminated (Glulam), Laminated Veneer Lumber (LVL), Parallel Strand Lumber (PSL) Advantages: less labour, stronger (no joints), good fire resistance (>2hr burn rating) Disadvantages: IAQ (formaldehyde off-gassing), higher cost o Steel I-beam Advantages: less labour (light), relatively inexpensive Disadvantages: poor fire resistance (<1hr), not attractive o "Built up" beam by laminating lumber - How to design a built-up beam o Code (NBCC) Minimum 3x lamination (ex. 3x 2x10") Locate butt joints over a supporting post of within 6" of span quarter point. No joints at either end. No more than half of the structural members have joints at any junction not over a post. Minimum of 3 ½ of foundation bearing (two stories only) To prevent decay, below grade beam must treated or have ½" space in between foundation walls. Above grade beam (within 6" AG) must rest on polyethylene/metal plate/impermeable membrane Beams can be nailed (every 12") or bolted (minimum ½" bolts) o Lamination: placing large timbers side by side and nailing them o Match crowns up Bending up (when weighted they go down) o No joints outside ¼" span o No joint on pocket beams o *sketch of built-up beams - does it meet code? o No joints side by side (exception to structural members) o Ex. CMHC spanchart Design a built beam in a basement of a two story house using No.1 fir (spruce-pine-fir) which will span 3m Given the supported length is 3.6m Note: supported length means half the sum of the joist spans on both sides of the beam Span and supported length info needed to look up on chart o Jackposts to reduce lumber (break span and add structural points) to make long spans

walls and stairs

step 6 - 2nd wall on top of sheathing - Vertically braced - Stairs comfort ratio to determine comfortable step (rules) o Comfort ratio o Metric: rise x run = between 451-484 cm o Imperial: rise x run = 70-75" o Metric: 2 Risers + 1 Tread = 61-63.5 cm o Imperial: 2 Risers + 1 Tread = 24-25" o Ex. Rise is 130mm (13cm), Run is 360mm Rise x Run = 468 and 2xRise + Run = 62 (OK!) o Ex. Rise is 200mm, Run is 235 mm Rise x Run = 470mm and 2xRise + Run = 63.5 (OK!)

trusses and roof framing

step 7 - Truss roof pitches: rise/runo Short form notation used industry o Calculating the angle requires basic trig o Tan()=Rise/Run ; = tan-1(Rise/Run) o Ex. 4/12 roof has a 4ft vertical rise for every 12ft horizontal distance (run) Angle is therefore = tan-1(Rise/Run) = 18.43 Note: -1() is the arctangent or tan-1() = atan() = arctan() - Truss system (pre-order trusses, drop in place) - 10.5/12 roof for tiny house - 24" spacing for truss system - Rafters vs Trusses o Rafter Boards with overhang, ridge beam (structural members where rafters meet) Sits on walls themselves Birdsmouth cut (where rafter meets wall, where the rafter/truss sits on the wall top plate) Ceiling joist - rafting tie (lateral resisting frame) Rafters carry loads from roof down to foundation Max 1/3 rule (~40%) • Member will break under large load o Trusses Advantages: costs less, uses less wood, longer spans, less time to install (can be crane into position) Disadvantages: trusses are engineered (required design), rafters allow for a more open design, ok for small buildings, good for remote projects o Note importance of ridge beam o Make sure to include eaves (overhangs) on tiny house Keeps water off wall assembly • Allows wet walls to dry • Keeps water off roof away from foundation Shading during summer (passive solar)

roofs

step 8 - Different roof types - Ceiling joists: for structural stability, rafters in gable and hip roofs must be securely tied together at the top of supporting walls by well-nailed ceiling joists to make a series of triangular trusses - Ridge beam (or bearing wall): inserted at the ridge or a system of exposed horizontal ties must be used in place of the joists if designer wishes to eliminate the ceiling joists and expose the sloping underside of the roof as the finished ceiling surface - Rafter ties: sometimes designer wishes to raise the ceiling joists or exposed rafter ties to a higher elevation than the tops of the wall plates. This greatly increases the stresses in the rafters and should be done only within the prescriptive limits of the building code or after consultation with a structural engineer - Ceiling joists and rafters protected against overturning - Dormer types and framing detail - Wood frame: sheet metal connectors

sole (bottom) plate

the crosspiece at the bottom of the wall in a wall structure

top plate

the crosspiece at the top (frequently doubled for strength) of the wall in a wall structure

Atmospheric dissipation

the length of atmosphere the sun's rays must pass through affects the intensity of the radiation received by the Earth When the sun is at its apex (noon), the sun's rays travel through the least amount of atmosphere As the sun moves closer to the horizon (sunset), the path of the sun's rays through the atmosphere lengthens The more atmosphere the radiation must pass through, the less its energy content due to increased absorption and scattering in the atmosphere

what causes the seasons?

tilt of the Earth (declination)

diffused radiation

when direct radiation is scattered by dust, air molecules and clouds

Wind rose

wind speed, direction (from which the wind blows) and probability of occurrence