English

Building and ductwork leakage are detrimental to energy conservation, comfort, and hygiene. They can cause building damage and it can prevent proper control of the ventilation airflow rates. Through the ASIEPI project, we have identified that while some key elements for a market transformation on envelope airtightness are under development in many countries, status quo seems to prevail for the duct market. With the objective of all new constructions being “nearly zero energy buildings” in 2020, policy makers need to know how better airtightness can be stimulated.

A full size simulation laboratory aircraft cabin comprising three rows of seats has been built. This represents the Airbus A320 and the China C919 aircraft. Experimental research on the attenuation rule of the individual air-conditioning isothermal jet flow from nozzles positioned above the seats was conducted. The results show that axial air velocity continuously decreases with increasing cross-sectional distance. For a distance x < 0.4 m, (the axis air velocity sharp attenuation area), the velocity of attenuation slows.

The redispersion factor of microbe-carrying particles, which is the ratio of the concentration of floor-derived microbes in room air to those on a floor surface, was determined, as was the percentage of floor-derived microbes in room air. These relationships were shown to vary according to conditions in the room. Equations were derived that allow these relationships to be calculated for a variety of room conditions, including air supply rates, levels of personnel activity, and the effect of gravitational deposition on microbe-carrying particles.

In hot climates a comfortable indoor environment is important. Mechanical fans are often introduced to cool the indoor air. However, it has been found that the airflow from such fans is not comfortable, especially compared with natural wind. Artificial airflow in an enclosure has been known to disturb hair, irritate eyes, and distract occupants. This paper presents the result of an experimental study on the characteristics of household airflow inducing appliances. The details of experiments carried out in the laboratory are described.

Air movement in an indoor space may be experienced in very different ways. For persons feeling cool, air movement tends to be perceived as draught, whilst when feeling warm air movement may provide a desired cooling effect. In the transition zone it therefore seems difficult to use constant air velocity as a tool for cooling without creating draught problems. One possible way to use air movement as a method to improve thermal comfort, without resultant draught problems, could be to use intermittent air velocity instead of constant velocity.

This paper investigates the performance of a new attic ventilation concept using low-cost thermoelectric (TE) modules. Incident solar radiation heats up roof tiles thus creating a temperature difference between tiles and attic. By making use of this temperature difference, laboratory made low-cost thermoelectric modules, assimilated as roof tiles, could produce an electric current to drive a fan for attic ventilation. First, a low-cost TE module consisting of 7 couples of N and P type Bi-Sb-Te materials was fabricated on a 2x2 cm² aluminium substrate.

This paper reports on an investigation of the natural ventilation and heat gain reduction of a new façade design referred to as the Thai modern façade (TMF). Two configurations were considered namely: Thai modern façade wall (TMF) and Thai modern façade wall with fin (TMF-WF). The first (TMF) was composed of two layers which consisted of an inner layer of clear glass and an outer layer consisting of a combination of fibre cement and clear glass slats. The second configuration TMF-WF included an external layer made from aluminium fins and installed at the front of the outer layer.

There is a need for a greater understanding of the acoustical and airflow performance of interior openings, and of silencers implemented to improve their acoustical performance, in naturally ventilated buildings. This paper discusses preliminary, fundamental aspects of a study done to provide engineers and architects with optimal design techniques. It discusses the characterization of ventilator performance, including the definition of the open area ratio - a combined acoustical and airflow performance-optimisation metric.

Buoyancy-driven natural ventilation in ventilation shafts is investigated with a small scale physical experiment within a duct and CFD simulations of an office building. For a fixed exhaust opening, smaller shafts lead to higher flow rates in upper floors of a multi-storey building with a shared ventilation shaft. These higher flow rates are caused by increased vertical momentum within the smaller shafts that induce flow through upper floors, an effect referred to as the “ejector effect”.