English

Describes the application of the HERS BESTEST system to a building energy simulation computer program. There was good agreement between the simulation computer program predictions and those of the reference programs. Different simulation inputs can be the cause of major differences between program predictions. The authors recommended that the HERS BESTEST manual be modified to include detailed information about the house models used to generate the results with the reference software tools.

Included in applications of multizone airflow and contaminant dispersion models to specific buildings are air quality diagnosis, weatherization, smoke control, and pressure balancing for laboratory hood safety. States that uncertainties in model inputs mean that the benefits of these applications are not being fully realized. Emphasises the need for an economical test method that is as accurate but less intrusive and faster than incremental or component-by-component blower door testing.

Describes a study carried out to validate multizone airflow and contaminant migration simulation programs as they apply to the modelling of tall buildings. Tracer gas experiments were performed in a building on a university campus. A comparison was performed between the measured tracer gas concentrations from these tests and those predicted by a simulation program.

Empirical validation studies of the application of multizone indoor air quality models to residential-scale buildings are reviewed here. The focus is on empirical verification efforts. Models have also been subjected to analytical verification and inter-model comparisons. Not many of the empirical verifications reported statistical analyses of the comparison between measurements and predictions. Additional statistical analyses have been performed and reported if sufficient data were available in the literature. Measurement uncertainty was not dealt with in most of the published reports.

States that inconsistency exists in thermal comfort conditions for local air movement. It is difficult to study, apparently because of the concurrence of the natural convection produced by metabolic heat dissipation of a body and room air movement. Claims that the term local draft sensation can be divided into the physical stimulation of air movement and the physiological perception of a body to analyse such a sensation.

Describes the development of a particle imaging velocimetry (PIV) measurement system for use with full-scale room airflows. Two-dimensional airflows were measured in a full-scale room in order to validate the PIV system, using two typical ventilation schemes: cross-flow ventilation and return flow ventilation. In the former, a slot air inlet and a slot air outlet were positioned on opposite walls so the ventilation air moved across the room air space.

States that zero and low wind speed occurrences are often overestimated in standard meteorological data for use by HVAC engineers because of the use of the robust, rotating cup anemometers. Therefore the data would be expected to underestimate wind-driven natural ventilation as well as pollution dispersal. A comparison of rotating cup and ultrasonic anemometers carried out for this study indicated that the former can indicate zero wind speed over many hours in the day when speeds up to 1.5 m/s can be present.

A good air quality control system ensures that the most common harmful gaseous contaminants are kept below permissible levels particularly in forced ventilated spaces. Such a system can ensure a high standard of indoor air and a healthy environment. The volume of fresh air in a room can be adjusted according to the number of occupants and their level of activity. It is important to keep a vigilant eye on the levels of the most common harmful gases, because most of them cannot be detected by human senses.

This study was based upon a laboratory comparison of two air duct cleaning methods, mechanical brushing and compressed air cleaning. These methods were compared in three types of round air ducts: a metal duct without oil residual, a metal duct with oil residual, and a plastic duct. The level of cleanliness was estimated both by using the vacuum test method and visually, and the time each method took was recorded. Two rotating speeds of the brush and various brush materials were used.

Several problems can occur if the design, installation and maintenance of HVAC systems fail to follow appropriate standards. These include excessive installation and maintenance costs as well as hygiene problems produced by dust deposition and accumulation. There is no proper set of standards for biological risk assessments to prevent ventilation system pollution. All there is are a few guidelines on limit values of bacterial and fungal air concentration.