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carbon dioxide

The study of indoor air environment in a partitioned residential building.

This paper describes the measured and calculated results of air humidity and profiles of tracer gas in a residential apartment in Taipei city, Taiwan. A complete multizone indoor air quality model was used to evaluate the test results. The concentration of C02 were employed to investigate the indoor pollutant transport. Also, the indoor air humidity was studied in order to evaluate the indoor moisture effects on human. The data from the measurements were used as simulation input data for the calculation of indoor air flow rates and pollutant concentrations.

A decipol predictive controller for VAV systems.

Due to the lack of proper sensors for odours, the odour concept, involving the unitsolf and decipol, is of very little practical use with respect to automatic control of VAVsystems. However, the decipol level in a room may be predicted from the concentration ofCO2 and the amount of fresh air supplied. By using the CO2 level as a decisive variable ofthe occupant load within the room, the actual air quality (decipol level) can be predicted.Once the decipol level is known, it is compared to a given set point, thus enabling thecontroller to alter the air flow rate accordingly.

Evaluating building IAQ and ventilation with indoor carbon dioxide.

A number of approaches exist to evaluate building ventilation and indoor air quality. In some situations, the measurement and analysis of indoor carbon dioxide concentrations can be useful for understanding indoor air quality and ventilation. On the other hand, oversimplified descriptions of measurement procedures based on carbon dioxide have been presented, and there have been many instances in which indoor carbon dioxide concentration measurements have been misinterpreted and misunderstood.

Literature review on CO2 based demand controlled ventilation.

Many ventilation requirements and recommendations are in the form of outdoor airflow rates per person. Ventilation systems are therefore designed to provide a minimum level of outdoor air based on the designed occupancy level multiplied by the per-person ventilation requirement. Because the indoor generation rate of carbon dioxide is dependent on the number of occupants, it has been proposed to use indoor carbon dioxide concentrations as a means of controlling outdoor air intake based on the actual number of occupants in the space as opposed to the design occupancy.

How feasible are zero energy buildings?

In the discussion on practice-oriented measures to reduce the CO2 emission, one measure most demanded is the development of zero heating energy houses. The technology applied and investigated in the first pilot projects seems to indicate a possible future without any CO2 emission with respect to residential building. What is really hidden behind this technology and whether it is feasible to introduce it into construction practice, is to be discussed in this contribution with regard to practical experiences.

Totally metabolic?

In principle, the results of carbon dioxide monitoring can be used to evaluate building ventilation rates and provide an indication of perceived indoor air quality. Here we review current knowledge about the use of metabolically-produced co2 in indoor air quality evaluation and control.

Regional and national estimates of the potential energy use, energy cost and CO2 emissions associated with radon mitigation by sub-slab depressurization.

Active sub-slab depressurization (SSD) systems are an effective means of reducing indoor radon concentrations in residential buildings. However, energy is required to operate the system fan and to heat or cool the resulting increased building ventilation. We present  regional and national estimates of the energy requirements, operating expenses and C02 emissions associated with using SSD systems at saturation (i.e. in all US homes with radon concentrations above the EPA remediation guideline and either basement or slab-on-grade construction) .

Ventilation and air quality in an office building.

The aim of this study is to assess the performance of the mechanical ventilation system and air quality in an office building. The perfluorocarbon tracer (PFT) technique was used to measure air flow in an air handling unit and to estimate flow rates supplied to the office. In order to validate the PFT technique as a viable means of measuring air flow in the mechanical ventilation system, the PFT measurements were compared with measurements made using a pitot-static tube. Air exchange range, ventilation effectiveness and age of air were examined.