Intro
The virtual sensor, Air Exchange Rate, illustrates the estimated frequency with which the air within a room is replaced by outside air in one hour. It serves as a gauge of a building's ventilation efficiency and is quantified as air changes per hour (ACH).
Examining the Air Exchange Rate is significant in the context of:
Good Indoor Air Quality: A higher air exchange rate generally corresponds to better ventilation, leading to improved Indoor Air Quality.
Energy Efficiency: While providing sufficient ventilation is important, balancing it with energy efficiency is crucial. Analyzing the AER enables you to optimize ventilation systems, minimizing energy consumption.
Regulatory Compliance: Numerous building codes and standards stipulate requirements for minimum ventilation rates.
Virtual sensor
In Dashboard
You can find this sensor at the bottom of the device page with other virtual sensors. The data is available for every device with a CO2 sensor.
The blue line shows the Air Changes per Hour (ACH)
The transparent areas indicate the min-max within the hour
In API
The API includes the virtual sensor Air Exchange Rate. Once room information is provided, you can also access the virtual sensor Airflow, indicating the volume of air replaced and expressed in m³/h.
Sensor algorithm
The Air Exchange Rate is only calculated when people are in the room. The algorithm is based on current and historic data, and will be more accurate over time. The more data it can register, the more accurate it will be.
The algorithm achieves optimal accuracy in rooms equipped with mechanical ventilation. While it can also detect natural ventilation, such as opening a window or door, the sensor's precision is diminished in such cases.
The algorithm to detect the Air Exchange Rate is trained on the data of many rooms and buildings.
It creates a calendar when the ventilation has run or not, with the use of the building opening hours as a fallback
The algorithm maintains a historic ventilation calendar based on historic detected ventilation and entered building opening hours. It estimates the ventilation rate from historic and current IAQ data both in the different parts of the historic calendar.