Unresolved issues in natural ventilation for thermal comfort.

An historical background of fluid mechanics used in computation of natural ventilation is provided. Unresolved issues in computation of natural ventilation for thermal comfort are discussed. These issues include the influence of building porosity on wind pressure difference coefficients; wind shelter effects; indoor air flow resistance; air flow for thermal comfort and heat stress relief; air flow computation techniques; and natural ventilation in home energy rating schemes. It is concluded that despite rapid advances in sophisticated computer analysis techniques, development of simpler natural ventilation computation methods is needed for use in the preliminary stage of building design.