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Lecture 4: Heat Exchange - Coggle Diagram
Lecture 4: Heat Exchange
Building Purpose
Provide shelter
Comfortable internal temperature
Protection from weather
Security, privacy :
Modes of transfer (Qs + Qi ± Qc ± Qv ± Qm – Qe= 0)
Solar Heat gains (Qs)
Solar gain factor
Radiation heat flow
Window glass area
Air Movement (Qv)
Internal heat gains (humans) (Qi)
Transmittance value
Temperature Difference
Surface area
Building envelope (Qc)
Activity
No.of occupants
Mechanical introduction (Qm)
Building Configuration
Material Choice
Architectural Design
U Value
Low
good insulator
maintain comfortable conditions with less energy
U=1/Rt(Total thermal resistance)
High
High heatloss
Less insulation maintenance cost
Affecting Factors
Thermal Resistivity
r=1/k
Thermal Resistance
Wind Velocity
Thickness of material
Thermal Conductivity
Thermal Conductance
Unit Area
Difference in temperature
Thickness of material
