Submitted by Maria.Kapsalaki on Fri, 10/25/2013 - 19:12
Windcatchers are roof mounted devices that use the action of the wind to provide top down natural ventilation to a room. Here, fresh air is channelled into a room while, at the same time, stale air is drawn out. This provides a simple but attractive natural ventilation methodology that is increasing in popularity in U.K. schools. However, an analysis of system performance has largely been limited to laboratory based measurements and the use of CFD to generate predictions.
This paper reviews the literature for evidence of links between ventilation rates in dwellings and moisture related respiratory health with a particular focus on house dust mites (HDM) and fungal growth. There is general consensus that a link exists between ventilation rates in dwellings and respiratory hazards (for example HDM). There is also general consensus of a link between these respiratory hazards and respiratory problems, but it is not clear to what extent hazards cause ill-health.
This paper reports a critical analysis of the assessment of contaminant removal efficiency. Measurements have been carried out in a ventilated room equipped with a pine wood floor, which emits Volatile Organic Compounds (VOCs), considered as air pollutants in this paper. Thereafter, Computational Fluid Dynamics (CFD) simulations are performed. CFD results are compared to measurements to check their accuracy. Moreover, air quality within the ventilated room is numerically analysed via indices.
The concentration of CO2 was measured during driving the automobile and during standing. VOCsconcentration was measured during standing. Two ventilation modes were prepared; 1) all fresh airmode and 2) all re-circulation mode in the car compartment. The windows of the automobile werealways closed during this measurement. The ventilation rate and the airchange rate were determinedby the concentration of CO2.
This study was performed to investigate an influence of ventilation rate change on the level of aerialcontaminants in the confinement pig building. There was not significant difference in total dust and totalairborne microorganisms among three levels of ventilation rate (p>0.05) whereas the increasedventilation rate lowered the levels of respirable dust and gaseous compounds (p
In this paper, the experiment for moisture buffering and effect of ventilation rate and volume rate of thehygrothermal materials is described. The objective of the experiment is to make clear the relationshipsbetween the moisture buffering effect and, the ventilation and volume rates of the hygrothermalmaterials. In the experiment, a layer of gypsum board as hygrothermal materials is placed on theinterior surface of the test chamber (4.60 m3). This chamber is located in the climate room which cancontrol constant temperature and humidity level (20oC and 50%rh).
This paper reports on a field investigation of the effect of screening on the induced flow rate in solar chimneys. The solar chimney considered here was a roof solar collector (RSC). It is composed of CPAC monier concrete tiles, an air gap and gypsum board. Two RSC units were integrated into the south-facing roof of a centre single room house of 25 m3 volume. Different types of screening were considered, namely: mosquito net, square net, metal grille and nylon filter.
In the first phase of the current project, the ventilation rates of occupied houses in the northern region of Japan were investigated from 2001 to 2005. It was revealed that, despite installing mechanical ventilation system, low ventilation rate was found in many houses. The causes were believed attributing to lack of cleaning of grills, filters and insect protection meshes. The second phase of the project was to investigate the causes and resolve the problems. This project was started in 2005 and 12 houses installed with mechanical ventilation system were investigated.
The paper evaluates the potential work performance benefits of increased ventilation. We analysed the literature relating work performance with ventilation rate and employed statistical analyses. The studies included in the review assessed performance of various tasks in laboratory experiments and measured performance at work in real buildings. Almost all studies found increases in performance with higher ventilation rates. The studies indicated typically a 1-3 % improvement in average performance per 10 L/sperson increase in outdoor air ventilation rate.
This paper reports mainly on field studies were indoor overnight CO2 levels are monitored along with outdoor ventilation rates in bedrooms where room air conditioners are employed.The results of laboratory experiments using two typical RACs (room air conditioners) are also reported and discussed.