Together with the increased thermal insulation of our buildings, the importance of intelligent ventilation systems is rising in order to maintain a good indoor air quality and to minimize energy losses.
The following parameters have a direct impact on the health, the sense of well-being and the comfort of the residents:
- Temperature
- Relative humidity
- TVOC and CO2equivalent
As a specialist in control solutions for HVAC and ventilation systems, Sentera developed a wide range of sensors – each with its own, specific purpose. To guide you in the process of determining the correct sensor for your application, we will explain these different parameters in detail.
Temperature and relative humidity have a direct impact on the sense of well-being and comfort of the residents.
Dry air leads to dry skin, itchy eyes, and irritated nasal passages. It can cause a bloody nose or an itchy throat and can aggravate symptoms of the common cold and some respiratory ailments. It also increases static electricity, which you feel in your clothes and hair and on furniture and carpeting.
Too high relative humidity degrees will result in condensation forming on windows, walls and ceilings that are colder than the air temperature and potentially damaging building materials and causing odours in poorly ventilated spaces.
Since temperature and relative humidity are the basic parameters that determine the comfort and well-being of residents, most Sentera sensors can measure these.
VOC - Volatile Organic Compounds
The human contribution to indoor air pollutants has been historically correlated with CO2, which is commonly used as an indicator for insufficient ventilation in closed spaces, but this doesn’t cover the complete load.
VOCs or Volatile organic compounds are known to cause eye, nose and throat irritations, headache, drowsiness, dizziness, nausea, difficulty concentrating and fatigue. VOCs in indoor environments evaporate from substances such as cleaning products, adhesives, paints, new carpets, copiers and printers to building materials and furnishings. VOCs are also emitted from humans and animals in their breath, sweat and directly from their skin.
CO2eq - CO2 Equivalent based on the VOC measurement
For a more accurate indication of the indoor air quality, Sentera developed the TVOC sensors that can monitor temperature, relative humidity, ambient light and VOC levels. There is also the possibility to rescale the VOC measurement into a CO2 equivalent (CO2eq).
Among many VOCs, the new sensors have an increased selectivity to hydrogen (H2). In indoor environments, the H2 concentration is expected to correlate well with the CO2 concentrations as human breath contains significant concentrations of both CO2 (4 %) and H2 (10 ppm). Furthermore, humans are the major source of CO2 and H2 in typical indoor environments.
This makes it possible to distinguish the influence of human presence from other contaminants and control the ventilation system based on occupation of a space.
Ventilation in function of TVOC (or CO2eq) level is interesting in environments where indoor air quality need to be optimised on continuous base, such as living room, office buildings, certain industrial environments, etc.
09.07.2020
