Study Week

Pre-midterm

• So far, we have considered heat transfer in simple geometries such as large; plane walls, long cylinders, and spheres.

• approximated as one-dimensional for simple analytical solutions• are two- or three-dimensional and involve rather complicated geometries

for which no simple solutions are available.• An important class of heat transfer involving two surfaces maintained at

constant• temperatures T1 and T2. The steady rate of heat transfer between these

two surfaces• S is the conduction shape factor, which has the dimension of length,

• S depends on the geometry of the system only.

• k is the thermal conductivity of the medium between the surfaces.

The unit thermal resistances of various components used in buildingstructures are listed in Table 3–6 for convenience.

Heat and Other Forms of Energy

The First Law of Thermodynamics