ARCC 2202 Lecture Notes - Lecture 6: Mineral Wool, A.D. Vision, Emissivity
16 Dec 2016
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Lecture Six - WINDOWS + ENVELOPES
Heat transfer -
conduction, convection and radiation
Conduction: diffusion of thermal energy within a solid or between two objects in physical
contact.
Convection: transport of thermal energy from a surface by a moving fluid.
Radiation: transport of energy with electromagnetic waves.
Emissivity
range of number from 0-1
Emissivity is 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).
- Multi-layer walls: Equivalent R-value calculations
WINDOWS
Cut out: glazing and thermal spacers
too close or too far (best scenario is 1/4 inch)
Five 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
- terminology: conductivity, R-value vs RSI
describe the window type
window types:
casement
slider
hopper
awning
find more resources at oneclass.com
find more resources at oneclass.com
INSULATION
- Insulation materials: advantages and disadvantages (Warning: Wasn't covered in class, but it's
in lect05 slides 36 to 44)
spray foam:
-polyurethane
-high density 2 pound
-high density 1 pound
-low density 1/2 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
Batt - insulation:
-Mineral/Stone Wool, fiberglass (Roxul, etc)
-insulation is a rock-based mineral fiber insulation comprised of Basalt rock (volcanic) and
Recycled Slag (byproduct of steel industry)
-Adv: inorganic (no mold issues), fire protection
-Dis: Expensive and high emboddied energy (x20 cellulose insulation)
Glass-Wool/Fiberglass: spun from glass into fibers
-Adv: inorganic (no mold issues). Can be installed in a batt or blown-in
-Dis: high emboddied energy (x30 cellulose insulation), relatively poor insulation qualities,
no air-sealing properties
Cellulose
-Cellulose materials include newspaper, cardboard, cotton, straw, denim, sawdust, hemp,
corncob and a fire retardant
-Adv: Low cost, has some air-sealing properties (not as good as spray-foam), higher R-
value than fiberglass, low emboddied energy, natural product (fire-retardent borate is a salt,
20% of final product)
-Dis: can settle over time (needs to be densely packed/blown-in), can't get wet (water
intrusion can separate newpaper and fire-retardent)
Radiative heat Transfer
- Radiation is the only mode of heat transfer that can occur in a vacuum. This is why we
feel warm from the sun
Building Wrap
- Allows water vapours to pass through but not liquified water
ADV
DISADV
-High R-value
-Water seals
-air seals and insulates
-Off gassing
-flammable
-expensive
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Conduction: diffusion of thermal energy within a solid or between two objects in physical contact. Convection: transport of thermal energy from a surface by a moving uid. Emissivity is a measure of the effectiveness of a material in absorbing and emitting energy as thermal radiation (long-wave radiation). Emissivity, symbol , ranges from 0 to 1. An object which perfectly absorbs and re-radiates thermal energy is a called a black-body ( = 1). Cut out: glazing and thermal spacers too close or too far (best scenario is 1/4 inch) Terminology: conductivity, r-value vs rsi describe the window type window types: casement slider hopper awning. Insulation materials: advantages and disadvantages (warning: wasn"t covered in class, but it"s in lect05 slides 36 to 44) spray foam: Icynene: available in both open and closed cell options. Insulation is a rock-based mineral ber insulation comprised of basalt rock (volcanic) and. Adv: inorganic (no mold issues), re protection.
