What is Heat Transfer, Explain Heat Transfer, How is heat transferred
What is heat transfer speaks to explain heat transfer and how is heat transferred.
There are four methods of heat transfer, evaporation, conduction, radiation and convection. All are important in comfort cooling.
Evaporation has been explained in the section An Understanding of Cooling.
Conduction
This is the transfer of heat along a substance from an area of higher temperature to an area of lower temperature. This is useful in an air conditioning coil. For example where the the fins and tubing of the coil conduct heat from air passing through the coil to the colder refrigerant contained in the tubing.
Conduction also transfers heat of hot outdoor air through the walls of a structure to the cooler interior wall surface, thereby contributing to the cooling load.
Types of Heat Transfer
Radiation
This is the transfer of heat through air without substantially raising the air temperature. Radiation from the sun raises the temperature of the walls and roof of a structure thus increasing the cooling load surfaces to which the body would radiate heat, but this method has not yet been found practical.
Convection
This is the transfer of heat by the movement of air or a liquid. An example of this is found in the conventional air conditioner or systems that circulate chilled water through convectors. The air is cooled as it passes through the cooling coils of the air conditioner or convector.
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