Abstract:

The convective heat-transfer coefficient （CHTC） of the external surface of a building is an important parameter for the energy conservation of building and the urban environmental simulation. In this paper, the CHTC of building roof plane was measured in the field via the naphthalene sublimation method, and the results were com- pared with the simulated ones obtained by the computational fluid dynamics （CFD） method, with the feasibility of CFD method in the CHTC simulation of external surface being verified. Then, the CHTCs of the external surfaces of an isolated building and five kinds of building complexes were simulated via the CFD method. The results indicate that  for an isolated building, the CHTCs of the roof and the leeward wall are respectively the largest and the smallest, and the CHTC of sidewalls is almost equal to that of windward walls;  for building complexes, the CHTC increases with the gap between buildings ;  the CHTCs of the external surfaces of a tall building and its adjacent buildings are larger than those of other buildings; and  the change of inflow wind direction may result in the variation of CHTC of building surface. It is thus concluded that the CHTC of external surface of a building is greatly affected by the wind velocity, the wind direction, the building density, and the building height

Key words: building, external surface, convective heat-transfer coefficient, computational fluid dynamics