Operation and energy flexibility evaluation of direct load controlled buildings equipped with heat pumps

To date, the assessment of the energy flexibility to be delivered by existing buildings and by their legacy HVAC systems is hindered by a lack of commonly agreed-upon methodologies. There are many research works in the field; however, many of them are focused on the design stage or, in case of addressing building operation, they are based on controlled experimental set-ups. The novelty of this paper lies in the fact that it develops and validates an original methodology for the Flexibility Function estimation to evaluate the delivered energy flexibility of several Automated Demand Response services applied on different heat pump systems working under real operations. The active interaction with several electricity markets, ranging from the Spanish day-ahead market to the German and Swiss ancillary services markets, have also been evaluated during the winter and spring seasons. The method results showed that heat pumps could offer a significant potential of flexibility in the analysed countries. Nevertheless, it has also been envisaged that some restrictions concerning reaction times and reliability may affect its readiness for certain ancillary services markets. © 2021 Elsevier B.V