Submitted by Maria.Kapsalaki on Mon, 10/28/2013 - 12:15
In order to get more effective natural ventilation into a room with a single sided opening or large depth, two new window types have been developed in the laboratory. These are based on three new patent developments. The first window is defined as a dual level ‘up-down folio’ window which consists of two pairs of openable sashes with one pair placed directly above the other. The second is a multi-sash mid-pivoted window with vertical deflectors.
Submitted by Maria.Kapsalaki on Mon, 10/28/2013 - 10:39
To clarify the indoor climate in Japanese college classrooms, an air-conditioned, mechanically ventilated classroom of a university was surveyed. Temperatures, humidity and carbon dioxide (CO2) concentration in winter and summer were measured before, during and after lessons. The airtightness of the room and the airflow rate of the ventilation system were also measured. In winter, at an outdoor air temperature around 0 ºC and with the thermostat temperature of the air conditioners set to 30 ºC, the vertical difference in room air temperature exceeded 10 ºC.
This paper discusses the accuracy of commercially available flow hoods for residential applications. Results of laboratory and field tests indicate these hoods can be inadequate to measure airflows in residential systems, and there can be large measurement discrepancies between different flow hoods. The errors are due to poor calibrations, sensitivity of the hoods to grille airflow non-uniformities, and flow changes from added flow resistance.
Measurements on three gas and two electric furnaces have been made to examine the field performance of these furnaces and their interactions with their forced-air distribution systems. The distribution systems were retrofitted as part of this study and the impact of retrofitting on furnace performance is discussed. In addition to field measurements, this paper will discuss how forced-air furnace systems are treated in proposed ASHRAE Standard 152P, and applies the resulting equations to the systems tested in the field.
Submitted by Maria.Kapsalaki on Fri, 10/25/2013 - 20:11
This study evaluated various ventilation strategies for efficiently removing house dust in the indoor environment. Experiments and simulations were performed to study the flow and diffusion fields that are affected by different locations and shapes of outlets. In this study, two kinds of ventilation strategies were considered i.e. ceiling exhaust and slit exhaust. In each case, experimental measurements showed that the characteristics of airflow within the whole room are generally similar except for airflow close to the outlet. CFD flow field and diffusion field simulations were also made.
Submitted by Maria.Kapsalaki on Fri, 10/25/2013 - 18:48
Nowadays, the ceiling slot diffuser is very popular in offices. However one of the problems, for the producer and designer of linear diffusers, is to determine and specify correctly the throw-length data, in order to achieve optimal air movement in the occupied zone. Here, experimental studies were conducted to identify the variation characteristics in jet behaviour for ceiling slot diffusers. Nine cases, covering different aspect ratios, were measured under isothermal conditions in two test rooms using traversing measurement systems.
A building contains a number of large openings, such as doors and staircases. When the temperature of the spaces connected by these openings differs, the difference in density will cause air movements through them.Horizontal air movements through vertical openings in buildings, such as doors and windows are wellinvestigated while studies of air movements through horizontal openings, such as stairwells are less frequent and therefore this work focuses on this case.
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.
To evaluate the property of cross ventilation quantitatively, it is important that the calculated air flow field is compared with measurement. In this paper, the air flow field in the wind tunnel of the Building Research Institute of Japan (BRI) was calculated by CFD analysis using the standard k- e model, and the adequacy of the calculation was examined by comparison with measured values.
The present paper aims at investigating the indoor air quality in fifteen school buildings located in the greater Athens area. Experimental investigations were performed in fifteen different school classrooms and the concentration levels of various pollutants such as CO2, CO, TVOC, HCHO, and radon, were measured. Moreover, the experimental investigation included measurements of several environmental parameters such as temperature, relative humidity and air velocity inside each classroom, while ventilation was examined by estimating the air changes using the tracer gas technique.