measurement

Pushed at first by the labels backed onto the 2005 French energy performance (EP) regulation, and later on by the 2012 energy performance regulation, which imposes envelope airtightness requirements for any new dwellings, and pulled by a growing interest for low-energy labels, an important market transformation is observed in France on envelope airtightness measurement.

The airtightness of office and educational buildings influences energy use and thermal comfort. A leaky building is likely to have a high use of energy and thermal discomfort. The knowledge of real airtightness levels of entire buildings and their impact on the energy use is very low, except for a study carried out in the USA. Therefore two different methods of airtightness testing were applied to six entire Swedish office and educational buildings built since 2000. The first method involves using the ventilation system of the building and the second one to use a number of blower doors.

Tracer gas measurements are an unparalleled means of measuring air recirculation, leakage, and air flow rates in air handling systems [1-5]. However, such measurements are subject to significant measurement uncertainty in field conditions. A common problem is imperfect mixing of tracer gas.

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.

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.

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.

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.