English

At present, Computational-Fluid-Dynamics (CFO) with the 'standard' k-e model is a popular method for numerical simulation of room airflow. The k-e model needs a lot of computing time and large a computer. This paper proposes a new zero-equation model to simulate three dimensional distributions of air velocity, temperature, and contaminant concentrations in rooms. The method assumes turbulent viscosity to be a function of length-scale and local mean velocity.

A pressure-equalized rainscreen (PER) wall is a multiple-line-of-defence approach to rain penetration control. This Update defines pressure equalization and discusses the various elements that must be incorporated in a PER wall to minimize rain penetration due to air pressure differentials.

Convective heat transfer from internal room surfaces has major effect on the thermal comfort, air movement and heating and cooling loads for the room. Recent studies have shown that the values of convective heat transfer coefficient used in building thermal models greatly influence the prediction of the them1al environment and energy consumption in buildings. In computational fluid dynamics ( CFD) codes for room air movement prediction accurate boundary conditions are also necessary for a reliable prediction of the air flow.

The numerical evaluation of room air movement is made by systematic discretization of space and the dependent variables. This makes possible to replace the governing differential equations with simple algebraic equation. The dynamic model of the temperature is based on the energy balance equation, considering a given flow field. The temperature in a given control volume depends on the temperatures of its corresponding neighbours. This form of the model is. not appropriate for control theory.

The performance of a glazed solar chimney for heat recovery in naturally-ventilated buildings was investigated using the CFD technique. The CFO program was validated against experimental data from the literature and good agreement between the prediction and measurement was achieved. The predicted ventilation rate increased with the chimney wall temperature. The effects of solar heat gain and glazing type were investigated. It was shown that in order to maximise the ventilation rate in a cold winter, double or even triple glazing should be used.

This paper describes the measured and calculated results of airflow rates and pollutant concentration profiles in an airtight test house, the aim being to evaluate the calculation model COMIS for multizone air infiltration and pollutant transport. Firstly, the leakage areas of internal doors, exterior walls and windows were measured by the fan pressurization method. Secondly, two measurements were carried out, assuming that the test house consisted of ten zones.

A two-dimensional turbulence k-e model is used to predict distribution of air velocity, temperature and turbulence kinetic energy in an air-conditioned room using ceiling air supply. Mixing characteristics of the airflow are analyzed under different air supply velocities and temperatures. A modified Archimedes number is correlated with the parameter ·characterizing heat transfer, ventilation system, and turbulence kinetic energy of room air flow. Significant correlations have been shown.