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Lecture 4 - Heat Exchange Process and U-Value - Coggle Diagram
Lecture 4 - Heat Exchange Process and U-Value
Solar Heat Gain from Window
Qs + Qi + Qc +Qv + Qm - Qe = 0
Solar radiation through transparent surfaces
Qs = A x I x 0
Heat Exchange through Air Movement
Convention of heat flow between interior and open spaces
Qv = 1300 x V X AT
Conduction of Heat by Building Envelope
Conduction through a wall
Qc = A x U x AT
Internal Heat Gain
Qi = Activity x No. of Occupants
U-Value
What?
Effectiveness to prevent heat from transmitting between the outside and inside of a building
Low U-Value = Good Insulator
Factors that Affect U-Value
Thermal Conductance
thickness of a material
Thermal Conductivity
The quantity of heat transmitted through a unit area and unit thickness of material in unit time when unit temperature differential exists between opposite surfaces
Thermal resistivity
Time required for one unit of heat to pass through the material surface area and thickness when unit temperature difference exists between opposite site faces
Case Study