IJV3

In dwellings there is a desire to reduce ventilation heat loss, by reducing uncontrollable air infiltration, at the same time as providing adequate indoor air quality by controllable background ventilation. In England and Wales, the background ventilation requirements in part F of the Building Regulations at present are expressed in prescriptive terms. The adopted European Standard, EN13141-1:2004, provides a means of assessing the performance of background ventilation devices, such as trickle ventilators, and gives a standard method of measuring the equivalent area of the ventilator.

The term air conditioning not only prescribes comfort temperature and relative humidity, but also the quality of air inside the room. Indoor Air Quality (IAQ) has become a concomitant of air conditioning. The pollutants generated inside the room affect the quality of air inside the room. The major pollutants considered are occupant generated (carbon dioxide - CO2, odour), sulphur dioxide and toluene etc. The monitoring and controlling of all pollutants is cumbersome.

‘Supply air’ windows are designed with an air gap between the inner panes of glass that is used as the incoming air path for room ventilation; air is pre-warmed within the window and thereby avoids the sensation of draughts. A series of tests, verified by model simulations, were carried out to determine those aspects of the window’s specification that govern the extent to which air is pre-warmed by the windows before entering rooms.

A methodology is presented for determining the air flow rate through a stack-ventilated single-spacedenclosure bearing a roof-mounted ventilation tower. We develop a "system discharge coefficient" which takes into account the pressure losses that occur at the intake opening of the enclosure, inside the tower and at the outlet opening. The system discharge coefficient is interpreted as a reduction in the area of the path that the air flow takes. Based on this reduced area the air flow rate is then determined.

The purpose of this study was to find out the local intensity and extent of doorway draughts, the functioning of air curtains, and the variation of the neutral pressure levels in 18 industrial premises. The doorway draught can reach the whole workspace and all the employees. At the doorline, close to the doorway, the thermal conditions can be even harsher than those outside. Air curtains significantly decrease the fluctuation of the temperature at work sites, but the functioning of the same type of air curtain varied substantially between the buildings.

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.