IAQ

In recent years, in the quest focused about energy conservative building design, as a high efficiencyair conditioning scheme, the variable air volume (VAV) systems owe their growing popularity in heating,ventilation and air conditioning (HVAC) applications. This paper reports the simulation study toinvestigate the inherent operational characteristics of direct expansion (DX) VAV air conditioning (A/C)unit when the supply air fan and compressor speeds are varied based on the thermal load persisting inthe conditioned space.

In recent years, volatile organic compounds have caused chemical sensitivity by increasing indoor airpollutant concentrations. In order to solve the problem, Ministry of Health, Labour and Welfare ofJapanese Government established the guideline values for indoor air concentrations for 13 compounds,such as formaldehyde, acetaldehyde, toluene and so on.

When a building is used only for intermittent occupancy, continuous operation of ventilation system isnot necessary for achieving good indoor air quality during the occupation periods. Such buildings havea great energy saving potential which is not harnessed enough yet. Indeed, energy loss can be avoidedby promoting natural means and managing mechanical ones.

Reinforcement of air-tightness and thermalinsulation in the indoors leads to the declinein air-change rate. Moreover, due toincreased chemical substances on furniture,the indoor air-quality becomes worse andmay induce various health problenls, namelythe condition known as the Sick BuildingSyndrome(SB S).Many tools and methods are being developedto improve indoor air-quality.

This presentation will make the audience aware of the importance of ISO-recognized certificationprograms in the testing adjusting and balancing and commissioning of HVAC systems. ImportantISO 17024 standards will be covered as well as their importance. Many faults have been found inexisting testing adjusting and balancing and commissioning certification programs ranging fromconflicting issues within the organization and their testing procedures; political control over theprocess; inconstant certification methods; geographical differences.

In most conditioned spaces, the Mixing Jet Ventilation (MJV) systems are commonly installed. Relying on turbulent mixing, MJV homogeneously controls the room environment. However, Indoor Air Quality (IAQ), draft, and noise can sometimes be drawbacks of MJV systems. In late the 70s, Displacement Ventilation (DV) was first introduced. By supplying low supply velocity air from the floor or lower wall, a stratification zone is formed which forces pollutants to be collected near the ceiling and allows clean air to remain in the breathing zone.

In most conditioned spaces, the Mixing Jet Ventilation (MJV) systems are commonly installed. Relying on turbulent mixing, MJV homogeneously controls the room environment. However, Indoor Air Quality (IAQ), draft, and noise can sometimes be drawbacks of MJV systems. In late the 70s, Displacement Ventilation (DV) was first introduced. By supplying low supply velocity air from the floor or lower wall, a stratification zone is formed which forces pollutants to be collected near the ceiling and allows clean air to remain in the breathing zone.

Investigates IAQ by making subjective assessments of perceived air pollution caused by human bioeffluents. A panel comprising 107 people reported on odour intensities and acceptability of bioeffluents from 54 other people as occupants. Twenty per cent of the judges described dissatisfaction caused by bioeffluents at 1.5 on the Yaglou's odour intensity scale. To satisfy 80% of the judges entering the chamber, a ventilation rate of around 7 litres per second per person was necessary.

Discusses this rarely examined aspect of indoor air quality. Specifically describes a study carried out on an unoccupied apartment on a road with heavy traffic, on the third floor of a block dating from 1955. The aim was to evaluate the transfer of pollution between outside and inside. Parameters considered were ventilation status, season, outdoor pollution levels, and the presence of adsorbing materials.

The article presents IAQ requirements for healthy office buildings in Nordic climates, based on the results of an epidemiological study of a multistorey office building in Helsinki, Finland. Summarizes the results of the study and gives recommendations and their limitations.