Basic Concepts

The engineering discipline of heat transfer is concerned with methods of calculating rates of heat transfer. These methods are used by engineers to design components and systems in which heat transfer occurs.

(1) Temperature: Degree of molecular movement

S. l. °C, K I-P: °F, °R


(4) Specific heat: Cp (Btu/lb°F, J/kg K)

Heat needed to raise temperature of 1 lb (1 kg) material for 1 °F (1 °C). O

(5) Heat capacity: (Btu/ft[1] °F) and thermal mass (Btu/°F)

Ability to store energy

Heat capacity = density x specific heat = p Cp

Thermal mass = density x volume x specific heat = p V Cp

(6) Energy change (heat transfer): Q (Btu)

Q=p V Cp AT

Where p — density, V — volume, AT — temperature difference.

(7) Heat flow (heat transfer rate or energy change rate): Q (Btu/h)

Energy transferred per unit time.


Posted in Fundamentals of Heating. Ventilating, and Air-Conditioning