Heat Transfer Coefficient Of Concrete Wall

After adding 120 mm of sandwiched fly ash blocks the heat transfer coefficients are significantly reduced.

Heat transfer coefficient of concrete wall. Area is the area of the wall in m2 ueffis the effective heat transfer coefficient including the floor construction the soil and the thermal resistance of the interior and exterior air films. The results indicated that the heat transfer coefficient of a clay brick wall was lower than that of a recycled concrete wall which showed slightly better heat preservation. Flow type w m 2 k forced convection. H t heat flow btu hr w j s u overall heat transfer coefficient u value btu hr ft 2 o f w m 2 k a wall area ft 2 m 2 dt temperature difference o f k.

Wall 1 ottvw overall thermal transfer a area of glass wall 2 value for walls btu hr. Heat transfer definitions and symbols q thermal lransmission or rate of heat fiow. Remember the total r value is affected by whatever is adjacent to each side of the concrete. Convective heat transfer coefficients table chart the following table charts of typical convective convection heat transfer coefficients for fluids and specific applications.

8 2 equivalent r values for concrete walls and rofs. Assuming a 6 inch wall that would yield an r value of 0 54. Low speed flow of air over a surface. The quantity of heat flowing due to all mechanisms in unit time under the conditions prevailing at that time.

Multiplying that per inch value times the thickness of the concrete would give you an r value for the concrete. As you said heat transfer coefficient of concrete is highly dependent on the environmental conditions like wind speed humidity etc. In btu h or w. Typical values of heat transfer coefficient.

H t u a dt 1 where. Reff is the effective thermal resistance in m2 k w including the soil and the wall construction. For what you describe a workable resistivity would be 0 09 hr ft2 deg. Mechanisms relate to modes of heat transfer by solid con duction mass transfer gas conduction co vection and radiation.

The time rate of heat flow usually expressed. Where d i and d o are the inner and outer diameters of the pipe respectively.