Experiment-based testing routine to characterize building energy flexibility for potential aggregators

Abstract

The ultimate goal is to introduce a standardized routine to characterize flexibility of a given building for the purpose of potential flexibility aggregators. The routine should provide the characteristic demand response of the building under various smart-grid control signals (e.g. time-of-use (stage) pricing, real-time pricing etc.). The scope of this paper is limited to the experimental part, that demonstrates measured demand response provoked by testing sequences. The testing sequences were applied via cloud-based service to the building management system (BMS) of a mid-size office building in Prague. The evaluation is not limited only to power metering but also includes indoor environment quality (in terms of room air temperatures and CO2 concentrations), HVAC system and local meteorological data monitoring. The air handling unit (AHU) and cooling system response were investigated using ‘step’ and ‘modular’ testing sequences. The real-life experiments revealed authentic demand response allowing to characterize building flexibility in full details. The key findings are, that the operation of the HVAC system components can be blocked for relatively long period of time (2 to 5 hours in studied case) without any critical consequences to the indoor environment quality. Approximately 30 % of the total power load per the testing event can be considered as flexible. The quality of the power profile was found highly irregular. Due to the power profile fluctuation the ramping/modulation at the single building level was found ineffective. In contrary to the modular control, the multi-stage control led to more detectable power reduction. The stage type of control provoked more observable, reliable, and easier-to-predict demand response.