Infiltration has traditionally been assumed to contribute to the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Some studies have indicated that application of such a simple formula may produce an unreasonably high contribution because of heat recovery within the building envelope. The major objective of this study was to provide an improved prediction of the energy load due to infiltration by introducing a correction factor that multiplies the expression for the conventional load.
Increasing emphasis on energy-efficiency has many jurisdictions enacting stricter energy codes. Yet, these same green building codes typically do not adequately address ventilation when a building envelope is designed to both minimize infiltration/exfiltration and maximize thermal efficiency. Our company investigated an apartment complex in Southern California, U.S.A. that was designed 25% more thermally efficient than required by State Code. Within months of occupancy, the first complaints of biological growth at windows and closets occurred.
Mold in dwellings is a persisting complaint in moderate climates. Nine parameters intervene in it: (1) climate, (2) inside temperature, (3) vapor release, (4) ventilation, (5) lay out, (6) envelope thermal performance, (7) sorption inside, (8) presence of preferential condensation surfaces and (9) type of finish. Exterior climate acts as boundary condition while inside temperature, vapor release and ventilation belong to the living habits. The five others are design and construction related.
In Arctic and sub-Arctic climates, such as those in Scandinavia, multiple-glazing windows that consist of at least three panes are widely used. Typically, the replacement air for the extracted air, especially in low-cost accommodation with forced extraction, enters the interior space in the form of leakage flow through the window jambs and the walls or through the supply air vents. The temperature for the air entering the room is close to that of the outdoor air, which may cause a sensation of draft.
During the last 20 years, the humidity sensitive ventilation system evolved to products increasingly simplified thus standardised. At Aereco, there were 5 generations of extract units, each modification of product was due to a change in the acceptation criteria. In many countries, systems with variable airflows are accepted and recognised ; regulations moved. In other countries, the orthodoxy of the constant airflow of an air change per hour remains in force for simplifying reasons or by ignorance of the real interest.
Effective weather resistive barriers (WRB) perform important functions in retarding waterentry into walls and in controlling water vapor movement as well as the amount of energyattributed to air leakage (Burnett, 2000; Weston et al 2001). Recognizing this, a public andprivate sector research consortium was established to develop reliable and precise methodsfor evaluating their performance.This paper, third in a series, provides an overview of the most significant results obtainedduring the consortium work.
Findings about sick building syndrome in Sydney’s offices are presented. The aim is to ascertain whether perceptions of sick building syndrome in offices impact on discrete aspects of workplace performance and management. One hundred offices in the Sydney
For energy savings, DCV systems are more and more used in ventilation systems but toestimate their energy savings, variation of occupation in the building (in time and number ofperson) must be estimated. We have enquired on real occupation on site in 27 offices and 13meeting room in France. Occupation rates have been monitored either by webcam or byenquiry to the users. Results show very low occupation rates in meeting rooms although mostpeople feel they are very occupied. Yet effective time of meetings and number of occupantsare less than expected.
Natural night ventilation and an earth-to-air heat exchanger are applied in the low-energy office building ‘SD Worx’ in Kortrijk (Belgium). Temperatures measured during summer 2002 are used to discuss the operation and cooling effect of these passive cool
In the 1990's, concern about global warming has resulted in a resurgence of interest in naturally ventilated offices. The Belgian climate is particularly well adapted to apply cooling by natural ventilation. Indeed, except for a few hours a year, outdoor air temperature is lower than indoors. Lots of office buildings have no atrium or chimney to benefit from any stack ventilation. But natural ventilation can nevertheless be organized with only frontage windows either by single-sided ventilation or by cross ventilation.
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