IJV8

Designing for natural ventilation became permissible across an extended range of climate zones in 2004 with the incorporation of an adaptive model into ASHRAE's comfort standard (ASHRAE, 2004). This mainstreaming of adaptive comfort was further reinforced with the introduction in 2007 of a European standard (EN, 2007) that mirrored ASHRAE's precedent. Despite broad international acceptance and application of the concept, there remains a gap in the fundamental theoretical underpinnings of the adaptive comfort approach.

A simulation study on the reduction of cooling loads by utilizing cross-ventilation was performed for a typically shaped house as defined by the Architectural Institute of Japan. A reduction in cooling load of around 50% could be achieved when the windows were opened liberally at night compared with the cooling load when all the windows remained closed, regardless of building coverage ratio.

Recently, natural ventilation, which is a traditional cooling method in Japan, has become considered as the key method for cooling energy conservation. The results of experiments are presented to measure the indoor thermal environment and cooling power consumption in an experimental dwelling by simulating occupants' life-style including thermal control with natural ventilation and air conditioning. Based on the experimental results the cooling power consumption from July to September has been estimated.

Solar chimneys may provide enough ventilation to buildings when properly designed. Although many design tools, theoretical models and experimental studies have been reported, the impact of many design parameters such as the construction thickness, the thermal resistance of the walls, the absorptivity of the internal surfaces of the chimney, the thermal mass of the chimney and the type of glazing, is not well known. This paper aims to provide information on the optimum sizing of the above parameters.

In the light of global environmental problems, it is vital for buildings to conserve energy and make use of natural energies. Natural ventilation is one important method for achieving this. In houses, natural ventilation is a very attractive way to control the indoor environment. Compared to this, mid- to high-rise buildings include many closed spaces where windows cannot be opened and internal heat is trapped inside, which increases the cooling load. Based on this situation, consciousness of environmentally friendly buildings and utilization of natural energy becomes high.

This paper reports on the measurement results of ventilation rates in existing occupied houses in the northern region of Japan. A total of 61 measurements were made over a period of 4 years on 39 houses. Some houses were measured once a year over the four years investigation period. The ventilation systems equipped in some of the investigated houses were improved during the course of this investigation period. The effect of the improvement on ventilation airflow volume was reported.

It is not unusual to face moisture problems in buildings in cold climates and wet regions. It is, however, unusual to have the same problem in a relatively dry region such as Jordon, which has moderate weather conditions and mild winters. Nevertheless, a significant proportion of houses and residential apartments in Jordan are affected. The monitoring of inside air conditions, wall surface temperatures, ventilation and living style has shown that a high relative humidity (RH >75%) occurs at walls resulting in possible condensation.

Air supply volumes and velocities in cleanrooms are monitored by airflow measuring hoods and anemometers but these measuring methods can be inaccurate if used incorrectly. It is demonstrated in this article that measuring hoods are accurate if the air supply passes evenly out of the hood, as occurs when the air volume is measured from a four-way diffuser or no air supply diffuser. However, when a swirl diffuser was investigated, the measuring hood gave readings more than 50% greater than the true volume. The reasons for the inaccuracy, and methods to correct it were established.

Air curtains are used to eliminate airflows through doorways (doorway tightness). In this paper the impacts of air circulation, jet discharge momentum flux and nozzle design parameters on the tightness of an upwards blowing air curtain are presented. The tightness values were measured using a tracer gas decay method in the laboratory hall. Measurements were undertaken for two nozzle widths, 30 mm and 120 mm, and for two different discharge angles, 10° and 30°.

An experimental study of annular jets with central aspiration is presented. Two flow regimes were studied for creating either local air conditioning or local ventilation systems. The local air-conditioning system was developed by maintaining the same flow rates of the non-swirling annular jet and central aspiration. A new concept of a 'local ventilation system' was created by combining the swirling annular air jet impinging on the plate and central aspiration.