heat transferu value evaluation?

Question

The overall heat transfer coefficients (U-Values) are key factors in a cooling/heating load calculation as required for the sizing of HVAC equipment. Such values are generally taken from tables for different wall arrangements and materials and climatic conditions. out-line the theory behind the U-Value evaluation and to apply it to evaluate the U-Value of common walls in building industry (composite walls made of hollow bricks, plasters, coatings, etc…). Comparison with similar values taken from the tables is required along with an analysis of possible discrepancies

Answer 1

The Uvalue is the reciprocal of the Total Thermal Resistance (Rtotal).

Rtotal is made up of the sum of the resistances of the layers in the wall - both solid and stsationary air layers. Look these up in your book.

Calculate them for a few standard walls and compare with the U values given in your country's Building Standards reference.

Discuss the effect of 'heat bridges', surface and interstitial water condensation.
This all should take 4 to 8 sides of A4 paper.

Hope this helps. Good luck!

CopyLeft:RCat