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Sensors for demand-based ventilation

In recent years, the importance of efficient ventilation systems in buildings has become increasingly clear. Poor ventilation not only leads to discomfort for occupants but also has negative impacts on their health and wellbeing. One way to ensure efficient ventilation is through demand-based ventilation, which adjusts ventilation rates based on the occupancy and activity levels in a building. This is where sensors for demand-based ventilation play a critical role.
Sensors for demand-based ventilation

Sensors for demand-based ventilation are designed to detect occupancy, temperature, humidity, and other environmental factors in a building. These sensors provide real-time data that is used to adjust the ventilation rates based on the actual demand in the building, rather than using a fixed rate. This helps to ensure that the building is adequately ventilated at all times while also minimizing energy waste.
Occupancy sensors are designed to detect the presence of people in a room. The problem with classic presence Infra-Red (PIR) sensors is that they can only detect moving persons. When you sit still in a sofa, a PIR sensor will not detect any presence. Sentera has therefore chosen to use a light sensor. This sensor measures the amount of ambient light. The ventilation system can be controlled on the basis of this information. When the room is lit, there is activity and it must be adequately ventilated. When it is dark, the room is not in use and the airflow can be reduced to save energy.
Temperature sensors are another essential component of demand-based ventilation systems. These sensors are used to measure the temperature in different areas of the building and adjust the ventilation rate accordingly. For example, if the room is too warm and the outside air is colder, free cooling can be applied. The room can be cooled by supplying filtered, cold outside air. Of course, the dew point temperature must be monitored to prevent condensation.
Humidity sensors are also critical for demand-based ventilation. High humidity levels can lead to a range of issues, including mould growth, musty odours, and discomfort for occupants. Humidity sensors detect the humidity levels in a room and adjust the ventilation rate to maintain optimal levels. This helps to prevent issues caused by high humidity levels while also ensuring that occupants are comfortable. Relative humidity sensors are regularly used in damp rooms (e.g. bathrooms) to regulate the airflow in function of the humidity.
Residents produce CO2 while breathing. The CO2 level is therefore an ideal measure for the occupancy rate of a room. For that reason, CO2 sensors are also commonly used in demand-based ventilation systems. These sensors measure the level of CO2 in a room and adjust the ventilation rate accordingly. High CO2 levels can cause fatigue, headaches, and other health issues for occupants, so it is essential to ensure that CO2 levels remain at a safe level. When the CO2 level rises, an extra supply of fresh air is necessary to guarantee good indoor air quality. When the room is not used, the CO2 level will evolve to the outside air level and less supply of fresh air is required. In this way energy can be saved.
TVOC sensors or air quality sensors measure Volatile Organic Compounds. VOC or Volatile Organic Compounds 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. VOCs are known to cause eye, nose and throat irritations, headache, drowsiness, dizziness, nausea, difficulty concentrating and fatigue. Therefore, it is important to monitor the VOC levels and to extract the contaminated air from the area. TVOC is the sum of the different VOCs and is a good indicator of indoor air quality or IAQ.
In summary, sensors for demand-based ventilation play a critical role in ensuring that buildings are adequately ventilated while also minimizing energy waste. Occupancy sensors, temperature sensors, humidity sensors, and CO2 sensors are all essential components of a demand-based ventilation system. By using these sensors, buildings can adjust the ventilation rate in real-time based on actual occupancy and environmental conditions, ensuring that occupants are comfortable and healthy while also saving energy.
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