ESTIMATING DYNAMIC AIR CHANGE RATES (ACH) USING A CO₂ MODEL AND GLOBAL OPTIMIZATION
ss.1-2, 2026 (Hakemsiz Dergi)
- Yayın Türü: Makale / Özet
- Basım Tarihi: 2026
- Sayfa Sayıları: ss.1-2
- Dokuz Eylül Üniversitesi Adresli: Evet
Özet
Finding the correct air change rate (ACH) is very important for checking indoor air quality and building energy performance. Standard CO₂ decay methods usually assume that ACH remains constant, but in reality, it changes constantly. In this study, a two-state CO₂ mass balance model is developed to estimate the changing ACH values using experimental sensor data. Since air doesn't mix instantly in a room, a "sensor lag" equation is added to make the model more realistic. Adaptive Runge-Kutta algorithm is implemented to solve the equations. The main difference in study is that a global optimization method is used for the whole test period instead of solving it step by step. Developed algorithm finds the daily ACH profile in a single run by minimizing the Root Mean Square Error (RMSE) between evaluated model and the actual sensor data. The developed methodology is evaluated under scenarios with (occupied) and without (unoccupied) CO₂ generation in the test room over 5 different test days; a high degree of agreement is achieved between the numerical model and the experimental data. In conclusion, it is observed that the ACH of the test room is in between 0.05 and 3.5 h⁻¹ when the test room is empty, and between 0.05 and 14.3 h⁻¹ when the the test room in usage.