English

The non-uniform behaviour of the air inside a room, which is important in comfort analysis, can be evaluated by zonal models. While not as fine-grained as CFD simulation, they do give useful information about temperature and moisture distributions that is not available from lumped-parameter models. Therefore, we have developed a tool, called SimSPARK, to automatically build dynamic zonal simulations of a building zone.

The aim of this paper is to discuss the impact of the relation between varying indoor and outdoor conditions on the ventilation loads of buildings and to provide HVAC designers with the respective information needed for the optimum dimensioning of the system. The total load generated by one litre per second of fresh air brought from the outside environment to the indoor space conditions, called -ventilation load index-, is calculated for the cities of Athens and Thessaloniki, Greece. The same principles can be applied to other locations.

One of the two air distribution systems serving the office rooms of a 25-year-old large office building was balanced in autumn 2002. The supply and extract air flow rates of 173 office rooms were measured before and after balancing. Before balancing, the air flow rates varied considerably from room to room and many of the office rooms were over pressurised. The average extract air flow rate in the whole of the building was 20.7 L/s.person and the standard deviation 11.0 L/s.person. The aim of the balancing process was to meet the design values dating from 1978.

In order to study the energy performance of a school building incorporating a hybrid ventilation system in Grong, Norway, a detailed field experiment was carried out.

It is only fairly recently that scientific and public concerns have focused on the probable health risk that the presence of air pollutants can cause in residential or non-industrial buildings. Several reasons have contributed to the deterioration of indoor air quality (IAQ) including some aspects of trends in the construction sector, most important of which are the design of buildings with increased air tightness for the sake of energy conservation but also the use of innovative building materials based on complex synthetic chemical substances.

The air conditioning of large non-domestic buildings is becoming an increasing trend, even in moderately mild climatic zones. This is often needed to avoid overheating that results from high internal heat gains and solar radiation. This paper describes work, undertaken in the United Kingdom, aimed at minimizing the need for conventional air conditioning in such buildings.

The work described in this paper formed part of the European UrbVent project on urban ventilation.Measurements of wind speed, wind direction, and air temperature were made at four different heights, inside a pedestrian street canyon in the centre of Athens, Greece, and at the top of the canyon. In addition, infrared radiation on the canyon faades was measured. Experimental data were collected at intervals of 30 seconds. The dimensions of the canyon were: height/width=2.3, length/height=50/23=2.2 with an orientation of 12 degrees from North.

This paper introduces a concept of robustness of an air distribution method, which is defined as being capable of meeting the ventilation requirements during varying operational conditions. The robustness performance may be particularly important when the system allows individual control of the supply air parameters. As a preliminary example, plenum-based (ductless) air distribution methods are studied using computational fluid dynamics.

Ventilation towers are often incorporated into the design of naturally-ventilated buildings. These towers increase the physical height of the building and thereby potentially enhance the buoyancy-induced air velocity. However, acoustic baffles, insect meshes, etc., placed within the towers result in pressure losses that effectively reduce the area of the flow path, thereby restricting the rate of airflow.

This research grows out of a desire to find a Solar-Wind Generated Roof Ventilation System for low-cost dwellings located in high building density urban areas where horizontal air movement is restricted. A general purpose computational fluid dynamics (CFD-ACE+) program was utilised to explore, analyse and develop a roof model based on its aerodynamics and thermal performance to obtain optimum wind pressure and temperature differences. Comparisons were made with physical scale models.