The overall thermal transfer value ( OTTV) concept has been extended to correlate the OTTV of building envelope designs with other key building design parameters through DOE-2 computer simulations. A survey of 146 commercial buildings completed between 1975 and 1995 provides the information on the prevailing architectural designs and construction practices in Hong Kong. This information forms a basis for the development of a generic office building used in the computer analysis.
Experimental investigations and practical experiences in Europe have proved that hydronic cooled ceilings are able to remove high cooling loads without impairing thermal comfort. As hydronic cooled ceilings cannot remove latent loads and pollutants, e.g., C02, VOCs, odors, additional ventilation has to be applied. Often, displacement ventilation is used, which is able to provide lower pollutant levels in the occupation zone than mixing flow systems, if the occupants are causing most of the pollution.
An environmental chamber has been used to compare the effectiveness of mixing and displacement ventilation in terms of heat and contaminant removal. Results are presented for CFD simulations of the air movement in the chamber and for measurements using a heated mannequin with displacement ventilation. The CFD simulations and the measurements suggest that displacement ventilation is more energy efficient than a mixing system.
A new method for compensating the space discretization error introduced when the fixed flow field is considered for the dynamic models of temperature distribution is presented. It is proved that the method generally used in literature is a particular solution of the proposed one. Moreover, it results in a continuous-time model, for which the integrating method becomes a free choice and a state-space representation is possible.
Login