Feasibility of balcony wall-mounted solar water heating system in high-rise residential buildings

The application of a solar water heating system is severely restricted by the limited roof area of high-rise buildings in urban areas. Therefore, the installation of a balcony wall-mounted solar water heating system (BWSWHS) on the facades of buildings has become an alternative solution.Annual conventional energy consumption and dynamic cost of three types of water heating systems were compared to prove the technical and economic feasibility of the BWSWHSs. First, the field measurement of the BWSWHS was conducted.Then, according to the principle of maximizing sunshine duration, the azimuth angle (AZ) of the building, suitable facade for installation, and optimal inclination angle of the collector were determined through sunshine simulation. Next, the annual heat gain and conventional energy consumption of the BWSWHSs were obtained from simulation using a verified model. Finally, annual energy consumption and dynamic cost of three types of water heating systems, namely, BWSWHS, electric and natural gas water heating systems, were compared. Results show that the optimal AZ of the building is 30° south by east, the suitable façade for installation is south, and the optimal inclination angle of the collector is 70°.In this case, the thermal efficiency of the collector is 44% and the solar fraction is 41%. Annual conventional energy consumption and dynamic cost are lower than that of the two other systems. The present study provides a basis for the promotion of the BWSWHS in residential high-rise buildings. © 2019 School of Science, IHU.