In this study, the function of carbon dioxide as an index of indoor air quality and as a tracer gas to estimate the air exchange rate in naturally ventilated single family houses was investigated. Carbon dioxide concentrations were measured continuously in the occupied room of six selected Irish houses for periods of 2 to 7 days. The air change rates were then calculated according to the mass balance equation and the time variation of carbon dioxide levels.

A method for estimating the time-varying intensity of emitting sources of a gaseous contaminant inventilated enclosures is proposed in this numerical study. A reduced model linking up a set of control points inside the domain to the contaminant sources is identified using the Modal Identification Method, from simulations carried out using CFD software. This reduced model is then used to solve the inverse forced convection problem consisting of the estimation of sources emission rates as a function of time from simulated contaminant concentration measurements.

The present work contains the details of an investigation of air diffusion and comfort issues of an isolation room of a hospital. Two types of cases have been chosen for a unidirectional ventilation system of the isolation room i.e. for immuno-suppressed patients and infectious patients. The patients body is simulated as a cylinder with approximate values for the physical and thermal properties of a human body and is treated as a constant heat source. The height of the inlet vent was varied and mean residence time and draught rating (DR) were studied.

When the airflow pressure losses at the junctions of ducts in ventilation systems are taken into account, the analysis becomes more complicated since no unique value for the static pressure is associated with a junction. Additional system equations expressing the pressure jumps over the junctions must be written down. A method to replace the junction losses approximately as equivalent channel section losses is presented. The method is based on dissipation considerations. Simpler system equations with fewer unknowns are obtained.

Case studies provide essential evidence about the performance of buildings. They also illustrate the methods by which a technology can be implemented as well as highlighting problems. Various case study buildings (both new and retrofit) that incorporate mixed mode, natural ventilation and low energy cooling are reviewed in this paper. An outline of the tasks that ventilation is required to perform is also presented. The results show that many buildings perform well and can provide good thermal comfort and air quality for much of the occupied period.

The purpose of this research was to assess the performance of air infiltration or naturally driven ventilation, the corresponding energy consumption and indoor contaminant level for residential buildings in Harbin, a typical city in the severe cold region of China. Based on questionnaire surveys and field measurements, a prototypical apartment building was determined. Then, unsteady-state numerical simulations were carried out by the use of COMIS. A parametric study on ventilation performance was undertaken based on applying various air-tightness levels.

Ventilation is essential for the health and comfort of building occupants. It is particularly required to dilute and/or remove pollutants emitted by occupants' metabolism and activities. The concentration of metabolic CO2 is well correlated to metabolic odour intensity. Therefore CO2 concentration can be efficiently chosen as an indoor air quality index when occupants are the main source of pollution inside the buildings.

An understanding of airflow patterns in operating rooms is required if the design of air distribution systems in such environments is to be improved and the risk of postoperative infection reduced. To assess a detailed description of contaminant distribution, the airflow patterns and the spread of contaminants in an operating room were analyzed using an experimental model. These experiments were carried out in a test cell, MINIBAT, equipped with an operating table, a medical lamp and a manikin representing the surgeon.

CFD modelling can be used in the design of ventilation systems. However, simplifications in room airflow models may lead to errors and discrepancies between predictions and reality. The aim of this paper is to present the problems and errors connected with the prediction of the air distribution based on CFD codes. The sources of error are pointed out, as well as possibilities for eliminating or reducing them based on program options and experimental identification of the predicted flows. As an example, a real complex room was considered.

The buildings sector is a major energy consumer as it accounts for almost 40% of the EU’s energy requirements and for about 1/3 of the total energy related CO2 emissions. In 2003, the building sector accounted for almost 60% of the total net electricity consumption in the OECD countries. A large share of the electricity consumption accounts for space cooling which has shown an increasing trend in recent years. It is expected that, in future years, the economic growth of many countries and the increased living standards will boost electricity consumption for space cooling.