Theory of heat Flashcards
Standard atmospheric conditions
29.92” Hg on barometer(14.696 psia)
Lowest temperature in °F
-460°F(absolute 0)
Fahrenheit to Celsius
°F= (1.8x °C) + 32°
°C to °F
°C= (°F-32°) \ 1.8
Absolute temperature scales
°F= Rankine= -460°F
°C= Kelvin= -273°F
British Thermal Unit (BTU)
Heat content of a substance
Specific Heat
The amount of heat necessary to to raise the temperature of a substance 1°F per pound.
Specific Heat of water
1BTU/Lb
Specific heat of ice and steam
.5 BTU/Lb
Conduction
Energy actually moving from one molecule to another. (A stick in a fire)
Convection
Moves heat from one location to another by means of a fluid medium.
Ex. Furnace use blower to pass air over a heat exchanger and then to rooms.
Sensible Heat
When a change of temperature can be registered, heat intensity has changed.
Latent Heat
When heat is added but no temperature rise occurs. (Hidden heat)
Latent heat of vaporization
The amount of heat energy in BTU/lb required to change a substance into vapor.
Latent heat of vaporization of water
970btu/lb