A study of demand-controlled ventilation (DCV) and constant air volume (CAV) systems

One of the most common measures of IAQ (indoor air quality) is carbon dioxide, CO2, generated by human respiration, in particular, where the main source of pollutions are occupants. In this report, the occupancy-related pollutants are considered as the main pollutant source. However, other type of sources may also be removed satisfactory when governing the ventilation system for removal of

The verifying concept for the cleanliness of HVAC systems

The visual evaluation method has been created for a primary method to verify cleanliness ofHVAC system. The results of two simple measuring methods for thickness of dust and debriswere compared to accumulation values measured by vacuum sampling method. The thicknessof dust layer and the dust accumulation results correlated when the dust was homogeneousbut the correlation was poor if the quality of the dust varied. Both the field and laboratorystudies showed that a commercial contact method gave lower microbial counts than the swabmethod with cultivation.

Statistical analysis of parameters influencing the relationship between outdoor and indoor air quality

Within the framework of the French national research program PRIMEQUAL, measurementsof outdoor and indoor pollution have been carried out in eight schools of La Rochelle (France)and its suburbs. The buildings were naturally ventilated by opening the windows ormechanically ventilated, and showed various air permeabilities. Ozone, nitrogen oxides (NOand NO2), and particles (15 size intervals ranging from 0.3 to 15 m) concentrations werecontinuously monitored indoors and outdoors for two 2-week periods.

A questionnaire survey of special old age nursing homes and elderly health care facilities in Japan

We studies the conditions in special old age nursing homes and elderly health care facilities in Japanespecially in a region with a cold climate. A questionnaire survey for all special old age nursing homes and elderly health care facilities in Sapporo and Fukuoka City, and Hokkaido, Saitama, Kanagawa, and Osaka Prefecture, and Tokyo Metropolis was performed. The main questionnaire asks about heating, air-cooling, ventilation systems, sanitary systems and indoor air quality including bio-aerosol and odours.

Microbial contamination of indoor air due to leakages from crawl space - a field study

The aim of that study was to find out if a potential air flow from crawl space has an influence on the indoor air quality : is there a potential risk for the first floor apartments ? A balanced ventilation system is recommended.

Study of the effects of essential oils on microbes present in ventilation systems

Many studies have shown that ventilation systems often host bacteria and fungi that may bedangerous for the health of people exposed to them. This problem may be particularly acute inhospitals, where exposed people are more sensitive. The paper presents the methodologydeveloped to study the effectiveness of some plants extract, the essential oils to hindermicrobial growth, in order to propose an indoor air purification method based on thegermicidal and odorant properties of the essential oils. First results are encouraging.

Life-cycle assessment (LCA) of air-handling units with and without air-to-air energy exchangers

The life-cycle assessment (LCA) methodology is used in this paper to assess the environmental effects of air-handling units (AHU) over a 20-year life cycle. This assessment is based on quantifying the consumption of resources (energy and materials), the harmful emissions into the environment (air, water, and soil), and the potential changes in the environment (climate change, acidification, and ozone production).

Wheel selection for heat and energy recovery in simple HVAC ventilation design problems

This paper shows how air-to-air heat and energy system design problems can be formulated for a simple HVAC configuration and solved for the least life-cycle cost system while still retaining a small payback period. Mathematical expressions and design tables are presented to facilitate the design process. The design process is illustrated for the city of Chicago where both large heating and cooling loads occur in HVAC applications. The example design problem presented shows that

An Algorithm of Stereoscopic Particle Image Velocimetry for Full-Scale Room Airflow Studies

One challenge in indoor air quality studies is the measurement of three-dimensional air velocity profiles in an airspace so that the nature of airflow can be better understood and appropriate ventilation systems can be designed. There is much dispute over a variety of computational fluid dynamics (CFD) models, primarily due to a lack of credible data to validate those models. This study aimed to develop a stereoscopic particle imaging velocimetry (SPIV) system suitable for easurement of full-scale room three-dimensional airflow.

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