AIVC - Air Infiltration and Ventilation Centre

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air conditioning

Quality improvements in displacement ventilation. Kvalitetsforbedring ved fortrengningsventilasjon.

Gives a history of the development of air conditioning, and displacement ventilation in particular. Discusses the constant problem of working environments - contamination, and the 'side effects' of economy measures resulting from the 1974 oil crisis. Refers to collaboration between HVAC engineers and the health authorities. Recommends the use of displacement ventilation because of its improvement in air quality. Considers the problems caused by the use of floor coverings and filled carpets in particular.

Is there a minimum heating requirement for households?

This note arises from work to identify the effectiveness and cost of remedial treatments for condensation and mould problems in housing. Although the four factors - moisture generation, ventilation, insulation and heating - which control the likelihood of mould growths have long been established there hasnot been a straightforward way of showing their interrelationship, particularly where energy costs are important.

Measurement techniques for air infiltration in air-conditioned buildings and large industrial buildings/halls Messtechnik Luftaustausch in klimatisierten Bauten und industriellen Grossbauten/Hallen.

Reviews the literature on techniques of air infiltration measurement, including pressurization methods, use of tracer gas and thermography.

Case study of a sick building

Demonstrates that complaints by office staff about their physical environment are not necessarily caused by physical deficiencies. Trying to reduce the level of complaints by adjusting heating ventilating and air conditioning (HVAC) systems can therefore be an unrewarding task. Greater attention needs to be placed on - communications between management, those responsible for running HVAC systems and staff. Staff need the feeling that they can influence, if not control, their environment. Staff should also have more realistic expectations about their thermal comfort.

Sick building syndrome

Random samples of the workforces of an air conditioned and naturally ventilated building were interviewed using a doctor administered questionnaire. Large and statistically significant excesses of work-related nasal symptoms, irritation of the eyes, dry throat, headache, dry skin andlethargy were detected in the air conditioned building compared to the naturally ventilated building. In the air conditioned building, over 36% of those interviewed were suffering from a single symptom and few workers were symptom free.

An office environment - problems and improvements

The employees in a large office in Trondheim were complaining about headache, tiredness, sickness, allergic reactions in eye and nose, dry skin, respiratory diseases etc., and as usual they believed that their inconvenience was due tothe ventilating system. However, preliminary investigations did not verify this assumption, although it was evident that the heating and ventilating system was part of the problems. Measures included reduction of room temperature, antistatic treatment of carpets, and replacement of noisy ceiling diffusers.

HVAC system operational parameters affect airborne fungal levels in occupied spaces

The National Institute for Occupational Safety and Health (NIOSH) and the U.S. Army, Construction Engineering Research Laboratory (USA-CERL) have collaborated on a project that examines the influence of heating, ventilation, and air-conditioning (HVAC) system operational parameters on the levels of microorganisms found in a simulated office space. In these experiments, fungi were collected as representative microorganisms using side-by-side sieve and slit samplers. Experiments at USA-CERL demonstrated that fan coil units are a major source of fungal aerosols in the built environment.

Ventilation measures that affect the content of air ions in office premises

Results are given of the effect of ventilation rate, duct length and particle concentration on ion concentration under laboratory conditions. The effect of electrostatic fields is discussed.

Controlling indoor air pollution from tobacco smoke - models and measurements

Examines the effects of smoking rate, ventilation, surface deposition, and air cleaning on the indoor concentrations of respirable particulate matter and carbon monoxide generated by cigarette smoke. A general mass balance model is presented which has been extended to include the concept of ventilation efficiency. Following a review of the source and removal terms associated with respirable particulates and carbon monoxide, we compare model predictions to various health guidelines.

Energy conservation and air conditioning and ventilation installations Economies d'energie et installations de ventilation et de climatisation

Summarises in tables the energy consumptions of a block of flats and a single house demonstrating how the share of energy consumed for fresh air heating and domestic hot water supply increases significantly in line with improved thermal insulation.