Role of control strategies in unlocking energy flexibility using building thermal mass

Despite the concept of energy flexibility in buildings being widely recognised, unlocking its potential against different HVAC control strategies in commercial buildings is a relatively new research topic. This paper investigates how building thermal mass influences energy flexibility under different cooling and ventilation control strategies. To that end, this study utilises a virtual testbed for an office building validated using real-world data.

Simulations are performed taking into account an outdoor air reset control construct in combination with different cooling and ventilation strategies. Energy flexibility from the perspective of six real case scenarios are evaluated and compared against each other to assess the influence of control strategy on energy flexibility. The results indicate that, on average, the amount of electricity that can be adjusted through the temperature setpoint control strategy ranges from 0.4 to 1.7 W/m², depending on the building’s construction properties.

This maximum demand flexibility is typically observed around 1 pm. When an economiser is used, changes in HVAC temperature setpoint control can reduce electricity demand by up to 2 W/m². In contrast, when there is no economiser, the building can achieve maximum electricity demand flexibility, which is approximately 2.5 times greater than with the economiser, at an outdoor temperature of about 31°C.