modelling

Decision about the use of natural, mechanical or hybrid ventilation system in a building should be taken at the early stages of the building design. While for a mechanical system the decision may be taken on the grounds of purely deterministic procedures, the use of natural forces requires a different approach. Therefore, a simple tool is needed which, given a few important and readily known building parameters and information about the local outdoor climate, enables the designer to determine the most suitable ventilation system.

This paper justifies the need for an integrated approach to building performance assessment and provides examples of the technical appraisals that may then be enabled. The contention is that the use of design tools which focus on a single domain will result in sub-optimum design solutions in terms of indoor air quality, occupant comfort, energy use and environmental impact.

The purpose of this article is to evaluate the performance of an irregular grids finite volume method described in previous article with the use of standard test problem. In this regard, lid-driven cavity and skewed cavity flow have assessed the accuracy of the algorithm. The ability of the method to handle complex geometry is illustrated through some examples of airflow distribution in buildings with complex geometric configuration.

An irregular grids finite volume procedure is presented for flows in complex geometries. The technique carried out computation in the physical plane itself, without any coordinate transformation. Equations are written in Cartesian velocity components and are discrete in physical domain using a cell-centred, staggered grid finite volume method. It is shown that the present formulation ensures that computational scheme is diagonally dominant.

The paper simulates the airflow and temperature fields in a dome Shanghai International Gymnastics Center (SIGC) at one summer day with the computational fluid dynamics (CFD) software PHOENIS. The comparisons of indoor vertical temperature distributions show that the predicted results are in good agreement with the on-site measured ones. And some analyses on the thermal characteristics in the actual dome are carried out.

This paper presents a stochastic single zone model for a hybrid ventilated building. Wind pressure and stack effect are used to drive air through the enclosure assisted by a fan in case of insufficient natural driving forces. Based on Monte Carlo Simulation, the model calculates the time varying airflow rate considering the random nature of input. An important aspect when considering stochastic models for hybrid ventilated buildings is the control strategy. The airflow in the present model is controlled by a damper and a fan using a PI controller.

Describes an assessment using carbon monoxide and volatile organic compounds as IAQ indicators for indoor air quality in a representative underground parking facility. Measurements were made at different time intervals throughout the day. The EMFAC7F1.1 model was used to estimate vehicular emission factors. Concentration profiles were then assembled using a transient mass balance model.

Looked at seven residential buildings in northern England to analyse the causes of short-term variations in particle number concentrations. High short-term peak concentrations arose from cooking, smoking and physical activity. The loss rate of particles after emissions stopped depended on the particle size range. The relative importance of deposition and air exchange in particle loss rates were quantified by simultaneous measurement of particle number concentration and air exchange rate.

Describes a simple design tool called the 'office building module' (OPTI), which is intended to help building professionals to incorporate the impact of design choices on energy consumption when designing a project. Emphasises the importance of the program's user-friendliness, minimisation of data and speed. Dynamic thermal programs are needed to compute energy needs and estimate overheating. Current programs suffer from slowness and the need for large amounts of data.

Evaluates by measurement and computational fluid dynamic (CFD) modelling, the thermal performance of an atrium integrated with photovoltaic (PV) modules, situated at the Jubilee Campus of the UK University of Nottingham. The project monitored the internal and external environments of the atrium, and applied CFD to the prediction of its thermal performance. Investigated the effect of ventilation strategies on the performance of PV arrays. Found that CFD modelling showed that for effective cooling of roof mounted PV arrays, the air inlet should be situated close to the roof.