English

Second article in this series. Describes a second type of system that supplies 100% outdoor air, and is projected to save significant energy over standard HVAC. Notes that nearly all schools and large buildings in the US and many other nations operate on the principle that, to control energy costs, building ventilation systems must recycle a majority of indoor air that is already heated or cooled. In the name of energy conservation, many building owners and managers set their ventilation systems to bring in too little outdoor air.

Describes a three-year EU funded research project into the application of passive downdraught evaporative cooling (PDEC) to non-domestic buildings. This paper specifically discusses the use of computational fluid dynamics (CFD) to model PDEC. Using a hypothetical office building in Seville, Spain, it describes modelling techniques used and applications in an investigation of the building's performance.

A performance evaluation of two passive cooling strategies is presented: daytime ventilation and night cooling, for a six storey apartment building in Beijing and Shanghai, China. A coupled, transient simulation approach is used in order to model heat transfer and air flow. CFD is used to simulate wind-driven ventilation, and Fanger's comfort model is used for occupant thermal comfort. States that the results indicate the superiority of night cooling over daytime ventilation, although there is a high condensation risk. For Shanghai neither were found to be suitable.

Makes a comparison between the effects on thermal performance and energy use of a number of pre-cooling and ventilation strategies, suitable for use to reduce peak power demands in office buildings in moderate temperature regions. Describes how simulations were performed for different building envelope parts, and for two levels of internal heat load. Lists the results as significant reductions of required daytime peak power loads which may be obtained by cooling strategies that contribute to lowering the internal mass temperatures.

A study of passive ventilation of a one storey detached building. A hot element of the building, heated by solar energy, induces the air flow. It could be part of a roof or a wall, or a chimney drawing air into the building. No electrical power or mechanical installations are needed, so it is appropriate for use in remote areas and buildings which are not grid-connected. The method can be used to remove toxic gases such as radon. A steady state laboratory model was used for experiments and simulations in steady and transient states.

Explores the complexities of guidance for the ventilation of hygiene systems. The UK Health & Safety Executive estimates that 30 to 50% of refurbished buildings cause some form of sick building syndrome. It is obviously important that building managers take the necessary steps to establish programmes to maintain ductwork systems in a safe, effective and hygienic state. The UK Heating & Ventilation Contractors' Association and Building Services Research & Information Association have produced documents providing guidance on the hygienic maintenance and cleaning of ductwork.

Outlines a project to promote greater consideration of indoor air quality during building design. The project was commissioned to develop guidance on assessing the overall external pollution burden on a building and techniques for minimising indoor pollution from external sources. The guidance focuses on non-domestic buildings. It is nearing completion and is based on three main groups of pollution sources - long-range, intermediate-range and short-range.

Explains how natural ventilation can improve the environment for workers in industrial buildings as well as those in offices. States that in industrial buildings, the primary reason for installing ventilation has always been to avoid excessive internal temperatures, particularly in summer, and to provide fresh air to breath and remove odours. Waste heat from plant, processes, lighting and people is often the main problem today. Claims that natural ventilation is still an option today for cost and environmental reasons.

Maisonettes, duplexes and triplexes in the city of Montreal have enjoyed much success since they were first built some 60 to 100 years ago. They currently account for half of the city's dwelling units. However, they pose some problems in today's context. Current standards and various innovations in new housing construction serve to underscore some of the limitations. Rooms can be small, kitchen can be dysfunctional, there is little storage space. Describes research carried out to look at the potential for revitalizing plex housing.

States that condensation on windows is a major issue for building owners and managers. Tests were devised to counter the problems of sealing windows, test temperatures and cost and simulation testing for conventional testing procedures, and a database of windows that have undergone both tests and simulations for resistance to condensation was compiled. Three double hung windows of varying materials were tested as well as designs for air infiltration at several levels of airtightness.