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Carbon Dioxide Levels and Ventilation Rates in Schools

In the following, measurements of CO2 levels in seven classrooms in four schools are reported. Measurements were taken for approximately one week in each classroom during the heating season and the time-varying ventilation rates estimated. The results of the experiments show CO2 concentrations which are far beyond the guideline value of 1000 ppm (the average concentration during the occupied period was 1957 ppm). In some classrooms the level exceeded the range of the detector (4000ppm).

Energy labelling of existing buildings and their equipment: new procedures to assess possiblities for increasing energy efficiency while reducing CO2 emission and improving comfort.

Describes best practice for energy labelling for existing residential buildings in four countries. Also describes the specific features of a Belgian procedure for on-site evaluation of both equipment and building envelope. The results can be used by other countries as general guidelines to develop or optimise efficient and effective energy labelling procedures.

Energy consumption and CO2 emission due to HVAC in commercial buildings.

Describes part of a global study on carbon dioxide emission associated with electricity consumption in Belgium. Two commercial buildings were the subject of a simulation. HVAC energy consumption and corresponding CO2 emission were calculated after an identification of the heating and cooling demands. It was found that they are strongly dependant on occupancy rates, and coexist throughout the year.

Asthmatic symptoms and volatile organic compounds, formaldehyde and carbon dioxide in dwellings.

Explores possible relations between symptoms of asthma, building characteristics and indoor concentration of volatile organic compounds in residential buildings. 88 persons from middle Sweden were studied. Measurements were taken at home of room temperature, air humidity, respirable duct, carbon dioxide, VOCs, formaldehyde and house dust mites. Health tests were also performed. Found that symptoms related to asthma were more common in homes with house dust mites and visible signs of dampness or microbial growth.

Subjective indoor air quality in schools in relation to exposure.

Relates exposure measurements for indoor air quality in schools to perception of IAQ by employees. A questionnaire was used to gather information on subjective air quality, domestic exposures and health aspects. 38 schools were covered in the study. A 53% section of personnel reported bad or very bad indoor air quality. Worst reports came from the younger personnel, those dissatisfied with their psychosocial work climate and those not exposed to domestic tobacco smoke. Less IAQ dissatisfaction was reported for older schools and those with displacement ventilation.

CO2 concentration in a typical Hong Kong classroom.

This paper presents the feasibility of predicting the transient CO2 levels in a classroom. Air measurements in the classrooms were taken to determine the fresh air change rate and ventilation effectiveness by means of tracer gas method. The fresh air change rate, effectiveness, occupancy, and outdoor CO2 levels were used as inputs for prediction of indoor CO2 concentration. The general profiles of predicted CO2 concentrations are quite similar to that of the measured values. The ventilation rate is often overestimated.

CO2 and radon based dual-mode demand control ventilation strategy.

A dual-mode demand control ventilation strategy was developed targeting at using in institutional or similar buildings where the number of occupants varies frequently. One occupant-related and one non-occupant-related indoor contaminants were used as the indication signals to control the fresh air intake. The first contaminant is carbon dioxide, which is a good surrogate gas for bio-effluent and the second is radon which is non-occupant-related and had been identified as a major indoor air pollutant in some buildings in the university where this project has been carried out.

Numerical simulation of CO2 dispersion in an auditorium.

Describes a numerical simulation of carbon dioxide dispersion as a result of occupant breathing in the enclosed space of an auditorium. Considers lighting equipment, number of occupants, two different ventilation systems, air induction and abduction flow rate. Uses three dimensional geometry and turbulence effects.

Ventilation and air revitalisation on the International Space Station.

The International Space Station (ISS) is the biggest multinational space program ever with 16 countries involved. Since November 2000 the station is permanently occupied with a crew of 3 astronauts. Till 2006 the station will be further assembled and the crew will be increased to 7 astronauts. To maintain a comfortable and safe environment under micro gravity conditions in a completely sealed space habitat advanced ventilation technology had to be developed to maintain air temperature, air humidity and air velocity as well as contaminant concentrations well below required levels.

Effect of ventilation pattern on room air and contaminant distribution.

Investigates the ventilation efficiency of different ventilation patterns arranged by two inlet and two outlet diffusers at different locations. First performs a numerical simulation, then a laboratory test in a full scale test chamber to validate the results. A concentration decay of carbon dioxide was used to calculate the ventilation efficiency and air change rate for the test chamber. States that the location of diffuser rather than air change rate might dominate the distribution of supply/exhaust air in the study.

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