Controllable building load systems like Air Handling Units (AHU), chillers and humidifiers are important in demand side flexibility as they can beswitched on/off or increase/decrease in capacity, during power grid congestions and as balancing services. In this study the role of the demand-side isinvestigated, based on data of a typical Dutch office building with an integrated Battery Energy Storage System (BESS). Experimental studies areconducted related to Demand-Side Management (DSM) strategies, with the focuses on the effects of chiller load shifting strategies. The thermal comfort isassessed during the load shifting operations with the use of adaptive temperature limits (ATG). The load system flexibility potential depends on thethermal comfort and Indoor Air Quality (IAQ); load systems remain limited to the boundaries of comfort. Based on the chiller load shifting results, theBESS is applied as resource to lengthen the load shifting operations with interval/step current.