Heat Transfer Through Concrete Wall

In convection heat transfer the heat is moved through bulk transfer of a non uniform temperature fluid.

Heat transfer through concrete wall.

If it is open to the atmosphere for example the thermal resistance of the air film adjacent to a concrete surface in a still environment can significantly increase the system s r value. The second heat transfer process is convection or heat transfer due to a flowing fluid. The rate of heat loss through the wall is to be determined. H t heat flow btu hr w j s.

The room is heated with hot water baseboard installed in 1919. A plane wall is constructed of solid iron with thermal conductivity 70 w m o c. An insulated frame wall of a house has an average thermal conductivity of 0 0318 btu h ft r the wall is 6 in thick and it has an area of 160 ft 2 the inside air temperature is 70 f and the heat transfer coefficient for convection between the inside air and the wall is 1 5 btu h ft 2 r on the outside of the wall the convection heat transfer coefficient is 6 btu h ft 2 r and the air. If the area through which heat is transferred is increased by a factor of 2 then the rate of heat transfer is increased by a factor of 2.

Remember the total r value is affected by whatever is adjacent to each side of the concrete. The overall heat transfer coefficient the u value describes how well a building element conducts. The temperature is 150 o c on one side of the surface and 80 o c on the other. The conductive heat transfer through the wall can be calculated.

Dt temperature difference o f k. Assuming a 6 inch wall that would yield an r value of 0 54. Bureauofstandardsjournalofresearch of heat ofof of of of walls such of ofof of walls of however on thethe of of. H t u a dt 1.

The fluid can be a gas or a liquid. If the thickness of the material through which heat is transferred is increased by a factor of 2 then the rate of heat transfer is decreased by a factor of 2. Example conductive heat transfer. Thickness of the wall is 50 mm and surface length and width is 1 m by 1 m.

U overall heat transfer coefficient u value btu hr ft 2 o f w m 2 k. They used poured concrete strange i know for the walls. Heat loss through concrete wall i have a 600 sqft rec room built around the turn of the century. I have replaced all the windows in the room added insulation to the ceiling but the room is still too cold to use when the.

The heat transmission through a building wall or similar construction can be expressed as. 2 heat transfer is one dimensional since any significant temperature gradients will exist in the direction from the indoors to the outdoors.