Heating Ventilation Air Conditioning System Research Articles

Identification, Remediation, and Monitoring Processes Used in a Mold-Contaminated High School

Publisher Summary This chapter presents a case study in which a series of protocols was used to identify mold-related problems in a school building complex. Techniques such as dehumidification of the outside air for the heating, ventilation, air conditioning (HVAC) system, the reconditioning of the HVAC system, and the physical removal of mold growth sites were used in the remediation process. Post-remediation monitoring processes indicate that these techniques have been successful. The HVAC system is the primary means for maintaining control of moisture in a dry building. It is also the primary transport mechanism for airborne pollutants. Once the conditions are suitable for fungal growth to be established in a building, the HVAC system can transport pollutants to other potential growth areas. In the case study, the HVAC system is examined for design flaws, construction defects, and histories of operational failures.

Sick building syndrome

Sick building syndrome describes a number of mostly unspesific complaints of some occupants of the building. The exact pathophysiological mechanism remains elusive. It is a multi factorial event which may include physical, chemical, biological as well as psycological factors. In many cases it is due to insufficient maintenance of the HVAC (heating, ventilation, air conditioning) system in the building. Sign and symptoms can be uncomfortable and even disabling, which may include mucus membrane irritation, neurotoxic symptoms, asthma like symptoms, skin complaints, gastrointestinal symptoms and other related symptoms. There are various investigation methods to diagnose sick building syndrome, and on site assessment of the building is extremely useful. Prevention through a proactive air quality monitoring program is far more desirable than dealing with an actual sick building. Indoor air and the sick building symdrome serves as a paradigm of modern occupational and environmental medicine. (Med J Indones 2002; 11:124-31) Keywords: indoor air pollution, sick building syndrome, building related illness

Determination of sound quality of HVAC systems on trains using multivariate analysis

An attempt was made to develop a model describing annoyance of noises generated by HVAC (Heating Ventilation Air Conditioning) systems on trains. The work was performed in three sequential parts. The first part contained the recording and reproduction of the HVAC noises. A binaural recording technique was applied and headphones were used for the reproduction. The second part of the study included both subjective and objective evaluations of the recorded noises. In the subjective evaluation 33 subjects judged nine different noise stimuli on annoyance scales. In the objective evaluation several sound quality descriptors and the third-octave-band levels were calculated. In the final part of the study, multivariate analysis was applied to modeling annoyance of the HVAC noises on the basis of the sound quality descriptors and third-octave-band levels. An annoyance prediction model was developed based on sharpness, a sound quality descriptor that describes the high frequency content in the sound, and a newly developed descriptor, tonal ratio. The new descriptor identifies the tonal components by comparing the sound pressure level between 125 and 800 Hz with the two third-octave-band levels adjacent to it. The interpretation of the results is that high frequency content and tonal components are the main contributors to the annoyance of HVAC noises and is where the main focus should be addressed in order to improve the sound quality of future HVAC systems.