Heat:
Conduction-Convection-Radiation
Greenhouse Effect
|
|
|
News of Green Building Join our email list here. Green Building Directory
|
Conduction is the transfer of heat through a material. Heat is transferred directly in and through the substance. Conduction heat loss or gain results from the transfer of heat directly through the materials of the building envelope. If the outside temperature is greater than the inside temperature, there is heat gain from outside the building.
Convection is the transfer of heat from particle to particle. It is the transfer of heat by the movement of fluids such as air or water. For example, the heated air around a stove will tend to rise to the ceiling. We all know hot air rises and cool air sinks. That is natural convection. Forced convection refers to the use of fans or pumps to move a fluid/air and the heat contained in it. We generally have forced-air furnaces in our homes. Radiation is energy transmitted directly through space and does not require matter in transmission. All objects radiate energy or heat, which heats all cooler objects around it. Solar radiation passes through space to heat (and light) objects that it strikes. A person in a room with cold windows will radiate heat to them and that person will feel cool even if the air in the room is warm. The greenhouse effect is experienced first hand by entering a closed car that has been sitting in the sun. Solar radiation is primarily in the range of visible light, and readily passes through transparent objects, like the car window, then is absorbed by the objects inside and converted to heat. Much of the inside build-up of heat from the sunshine is due to the protection of the enclosure. It provides against heat loss by convective air movement. What happens if you park your car in the shade? Contact Terry Jensen at 972 251-1532 or 817 545-0140. |
Green Builders Green Building Glossary |
DFW Net Mall Homepage
More Green
Building
Contact
Copyright © 2006-2008 DFW Green Building. All rights reserved.