Energy performance of water flow window as solar collector and cooling terminal under adaptive control

Abstract

Renewable energy is extensively utilized in building section for the purpose of energy conservation. In the present study, energy-saving potential of water flow window system under adaptive control is analyzed. The system utilizes geothermal energy for indoor cooling and solar energy for water heating. The window design combines the functions of transparent envelope, thermal insulation, solar collector and cooling terminal. These advantages make the system especially suitable for regions with hot summer and high-density indoor cooling load. As cooling terminal, the temperature of glass surface can be adjusted simultaneously according to indoor and outdoor condition through regulation of water flow rate.Two system control mechanisms are proposed: i) M1, to achieve zero indoor heat gain through the water flow window, and ii) M2, to compensate indoor cooling load from both ambient environment and internal heat sources. Self-developed FORTRAN program is utilized to investigate its application and energy conservation potential as both solar collector and indoor cooling terminal. Thermal and energy performances under both control mechanisms are evaluated. The economic analysis shows a promising annual energy saving of 576.0∼1223.5 MJ for the 9 m2 water flow window. Results demonstrate preferable potential of double-circulation water flow window system application.