A study on price responsive energy flexibility of an office building under cooling dominated climatic conditions

Flexibility in buildings is a low-cost alternative to support the electricity network with high penetration of variable generation. There is a limited understanding of energy flexible behaviour of the buildings in response to electricity market signals. In this paper, the price-responsive flexible behaviour of a commercial building with a cooling system has been studied. A first-order virtual battery model of the building and flexibility function-based approach have been used to understand the flexible behaviour of the building to varying price signals. The price signals delivered changes in building electricity demand profile, altering cooling temperature set points. The building structural thermal storage capacity was found to vary depending on demand changes. Low price signals provoke positive demand changes with respect to the baseline demand, taking the system to charging mode. Similarly, high price signals lead the system to discharging mode, reducing the instantaneous charging condition of the system. HVAC operating states, e.g., free cooling/economiser cooling and mechanical cooling, have been found to have a notable impact on electricity demand flexibility. The flexibility function shows that for a very low-price value, the cooling setpoint approaches the lowest comfort bound, and demand increases significantly. A deviation between the maximum and minimum electricity demand of 207 kW for the studied building system gives an estimated maximum energy flexibility capacity of 7248.2 kWh. The response of the building to variable price signals yields flexible demand, delivering cost savings of 13 %.