English

Short analysis of possible retrofitting operations on the building envelope and on the heating system to save energy. An analysis of residential buildings in various parts of Italy has been performed using the Italian national calculation procedures (UNI) for the evaluation of winter energy need. A more detailed analysis in envisaged to extend the data obtained, using more sophisticated codes in order to calculate the annual energy consumption of the building. This would define normalised energy indices to ensure a more energy aware design.

Describes how a fully furnished two storey test house was used to perform an experimental study of tracer gas dispersion and airborne moisture movement. The test used two multizone models to simulate the experimental data. States that good agreement was obtained in the comparison and with the tracer gas dispersion. Finds that a representation of adsorption by indoor surfaces must be included in order to accurately model the airborne moisture movement.

Describes a new multicriteria analysis of ventilation during summertime in Europe. These theories are used to determine the best ventilation strategy on a university building, aiming to ensure optimum indoor air quality, occupant thermal comfort, and lower energy consumption when using accelerated diurnal or nocturnal ventilation and/or air conditioning. The article defines the possible actions, then the quality criteria for thermal comfort, indoor air quality and energy consumption.

States that it is difficult to achieve good mixing in a large space and that the usual methods to evaluate the ventilation system in such large spaces with the age of air measured by tracer gas is not often practicable. Proposes a new method to evaluate this ventilation, based on the normal step-down or decay method. A small control volume of tracer gas is used as opposed to filling the entire space. the local mean age of air is then measured in a study of the transient decay curve of the tracer gas concentration.

Explores how water gets into a structure, why it doesn't leave, and how these architectural flaws become HVAC problems. States that mechanical engineers need to understand the roots of the problems in order to defend their work if IAQ becomes a problem once the building is occupied. The article reviews air control and pressurization, ventilation and humidity control and provides some resources to help expand the reader's knowledge of design and construction errors that lead to HVAC problems.

States that the layout of the production line in any clean rooms is likely to change in accordance with the production process, and that this poses a problem for post clean room maintenance. One of the many problematic issues often found in the clean room environment is air velocity, and the ongoing problem should be addressed at upgrade time. The paper looks at the characteristics of airflow distribution within a clean room, as a result of changes to the production process. The study was conducted for a class 100 clean room at a manufacturing firm for disk drives.

The article examines the feasibility of using thermal performance lines in assessing the efficiency of using energy in air conditioned commercial buildings in Hong Kong. A regression study is outlined, which was aimed at identifying a suitable climatic variable that would yield linear thermal performance lines for Hong Kong commercial buildings. Researchers based the study on the monthly electricity consumption of 26 existing office/commercial buildings obtained from a recent survey.

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.

Due to infection risks, high demands are set for the air quality in operating theatres. This is normally realised through the use of a downflow plenum. In this article the application of a fluid flow simulation program (CFD), as a design tool for the evaluation of a new ventilation design for operating theatres, is discussed. In this case an alternative downflow plenum has been investigated, that differs from the currently common designs. The use of CFD allowed for the examination of important design criteria and the resulting adjustments to the design.

States that an air filter can prevent sources of infection entering the ventilation system. It keeps the ventilation system in good condition, and maintains the air flow rate, the temperature and the RH for which is has been designed. It also keeps the efficiency of the heat exchangers at a high level. The same areas of attention should apply to both the return system and the supply system.