A method for determining the time-dependent indoor CO2 concentration to evaluate air hygiene

Abstract

This paper deals with new ways to describe and assess indoor air CO2-levels to provide a sufficient clarity. Besides common illustrations of measured or calculated CO2 concentrations over a certain period of time different computed indicating values like CO2 hours over a specific threshold exist. However, most of these diagrams need interpretation by experts and a sum of CO2 hours over a specific threshold does not provide information on extreme values in difficult phases. Thus, a new kind of categorization and additional indicating value was developed. By generating ppm-hours as an integration of the C02 curve e.g. over 1000 ppm with the correlative time duration an advanced characteristic parameter can be proposed. Own calculations with dynamic thermal building tools (IDA-ICE) and measurements were applied to set-up use cases and validation. Further improvements could lead to a standard procedure in terms of the assessment of indoor air CO2-levels.