Evaluation of energy flexibility of buildings using structural thermal mass

Abstract

In order to mitigate the effects of climate change and to focus on sustainable development in the field of energy, the EU is committed to increase renewable energies and energy efficiency, as we see in the objectives "20/20/20" and in the strategies for 2030. Renewable energies solar and wind have had a great advance; however they are very unpredictable because they depend on the climatic conditions, which represent a disadvantage in its use. The development of these energies could be compromised by the problems that could cause in the stability of the electrical network if its penetration is high. There is a great deal of research focused on improving this situation of instability through energy storage and distribution. The demand management has been identified as a tool for the balance between energy generation and demand. It has been found in the construction sector a great opportunity, taking advantage of the fact that in 2020 all new buildings must be nearly Zero Energy Building (nZEB). The trend is that buildings will become energy producers, and to capable to store it. Then, determining the flexibility of a building's energy demand becomes the key to proposing energy consumption strategies that favor the stability of the power grid and the cost of energy. There are several alternatives to store energy in a building. Its thermal inertia can be widely used in heating and cooling systems, which represent the greatest demand for energy in a home. This study is focused on determining the energy flexibility of the heating system operation a nZEB using its structural mass. The energy flexibility has been tested implementing advanced control strategy without compromise the thermal comfort of the users. It has been evaluated with the indicators of available storage capacity and the energy storage efficiency proposed by Reynders