The effectiveness of a ventilation system in terms of the age of air and its ability to remove contaminants will be significantly affected if part of the exhaust air is recirculated. In this paper the consequences of recirculation of air in mechanical ventilation systems on ventilation effectiveness parameters is examined. Two alternative methods of establishing ventilation effectiveness parameters relating to air change efficiency and contaminant removal effectiveness when recirculation of air is present are presented.
Does your workforce regularly complain about irritating symptoms such as headaches, runny noses and itching? Have your supervisors noticed that people are taking much more sick leave, performing badly, or are unhappy with their surroundings? If so, it could be a case of Sick Building Syndrome. The problem could be with the building, the working environment or the way in which work is organised.
The fact that many people spent more than 90% of their time in a more or less artificial indoor environment (i.e. office, factory, home, transport vehicles etc.) stresses the importance of a proper indoor exposure assessment. When the personal exposure in a ventilated room is to be determined one may choose to perform a series of measurements or to use a model for calculation. Both approaches may lead to erroneous results if they are not treated properly. For instance C.E. Rodes et al.
This is the first part of a planned research into the effect of the human being on the indoor climate. The results are among other things intended for CFD calculations. This part deals with the influence from breathing, smoking, bioeffluents and vapour. The results are mainly based on measurements around a breathing thermal model placed in three fundamentally different types of indoor climates:
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