The sustainability of high-rise buildings is always a point of debate and doubt in current research and literature. Several studies have been performed about the zero-energy potential for skyscrapers, however taking into consideration single functions, particularly office and housing buildings. Realistic and modern tall building design however always involves a combination of uses (offices, accommodation, commercial and retail) for the project to be economically viable. On the basis of the Trias Energetica, the primary goal of the early design for sustainable buildings must be to minimize the demand for energy (heating, cooling, hot water, electricity) by means of active or passive techniques. This translates into design guidelines for the shape, orientation, building envelope and climate properties, parameters that have been already widely investigated by researchers and designers in practice. However, an important feature in order to improve the sustainable profile of a building is to employ circular techniques that aim to avoid wasting energy and re-use / re-purpose it. The main objective of this graduation research is to determine the zero-energy potential for high-rise buildings by taking advantage of a mixed-use scheme and examining the possibilities for energy exchange and cooperation between different functions by means of storing energy in the form of warm and cold-water tanks. This research aims to determine which synergetic combinations between functions can be performed, what type of building systems and technology can be used and, by establishing a complete energy simulation, conclude on what are the energy benefits for the building on a yearly basis . The results will be an important addition to the sustainable design for “MEGA” scale projects, according to the forthcoming Dutch regulation that after 2020 all newly built buildings must comply with the nearly zero energy guidelines.