Temperature: Degree of hotness or the level of heat intensity of a body is its’ temperature.
Calorific value of fuel: The total amount of heat liberated when a unit masss or a unit volume of fuel is burnt completely is calorific value of fuel.
Calorie: the amount of heat required to raise the temperature of one gm of water through 1°C (15°C to 16°C)
Kilocalorie: The amount of heat required to raise the temperature of 1 Kg of water through 1°C.
1 Kcal=1000 cal
CHU (Centigrade Heat Unit): The quantity of heat required to raise the temperature of 1 Lb (pound) of water through 1°C.
1 Lb=453.6 gm ie; 1 CHU=453.6 cal
B.T.H.U or B.T.U (British Thermal Unit): The quantity of heat required to raise the temperature of 1 Lb (pound) of water through 1°F.
One scale of temperature can be converted into another scale of temperature by the formula.
C/5= F-32
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Process of moving heat from one source to another is called heat transfer.
Heat can travel in any of three ways: radiation, conduction, or convection.
Conduction: It is the flow of heat through a substance. Actual physical' contact is required for heat transfer to take place between two bodies by this means. Conduction is a highly efficient means of heat transfer as any service-man who has touched a piece of hot metal can testify. Transfer of heat through solid material. Heat is carried through the atomic vibration & electron motion.It is due to the property of matter and heat transfers from one molecule of the body to another molecule without the motion of molecule.
Convection: It is the flow of heat by means of a fluid medium, either gas or liquid, normally air or water. Air may be heated by a furnace, and then discharged into a room to heat objects in the room by convection. Here process of heat transfer from one particle of the fluid to another particle by the accumulation of the heated particles of the fluid. Heat is carried by molecules.
It is due to the capacity of moving matter to carry heat energy. Heat is transferred by heat conduction & mixing motion.
Radiation: Process of heat transfer from one hot body to another cold body in a straight line without affecting intervening medium. Radiation is the property of all substances & each body emits energy and amount of energy emitted depend upon the temperature level.
It is the transfer of heat by waves similar to light waves or radio waves. For example, the sun's energy is transferred to the Earth by radiation. One need only step from the shade into direct sunlight to feel the impact of the heat waves, even though the temperature of the surrounding air is identical in both places. There is little radiation at low temperatures, and at small temperature differences, so radiation is of little importance in the actual heat transfer process.
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Latent Heat: The heat which changes the physical state of a substance without changing the temperature.
Specific Heat: The relative amount of heat required to raise the temperature of a unit mass of different substances by 1° compared with the amount of heat required to raise the temperature of the same weight of water by 1°.
METHOD OF HEAT TRANSFER
The important law of thermodynamics is that heat always travels from a warm object to a colder one. The rate of heat travel is in direct proportion to the temperature difference between the two bodies.Process of moving heat from one source to another is called heat transfer.
Heat can travel in any of three ways: radiation, conduction, or convection.
Conduction: It is the flow of heat through a substance. Actual physical' contact is required for heat transfer to take place between two bodies by this means. Conduction is a highly efficient means of heat transfer as any service-man who has touched a piece of hot metal can testify. Transfer of heat through solid material. Heat is carried through the atomic vibration & electron motion.It is due to the property of matter and heat transfers from one molecule of the body to another molecule without the motion of molecule.
Convection: It is the flow of heat by means of a fluid medium, either gas or liquid, normally air or water. Air may be heated by a furnace, and then discharged into a room to heat objects in the room by convection. Here process of heat transfer from one particle of the fluid to another particle by the accumulation of the heated particles of the fluid. Heat is carried by molecules.
It is due to the capacity of moving matter to carry heat energy. Heat is transferred by heat conduction & mixing motion.
Radiation: Process of heat transfer from one hot body to another cold body in a straight line without affecting intervening medium. Radiation is the property of all substances & each body emits energy and amount of energy emitted depend upon the temperature level.
It is the transfer of heat by waves similar to light waves or radio waves. For example, the sun's energy is transferred to the Earth by radiation. One need only step from the shade into direct sunlight to feel the impact of the heat waves, even though the temperature of the surrounding air is identical in both places. There is little radiation at low temperatures, and at small temperature differences, so radiation is of little importance in the actual heat transfer process.
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