Numerical simulation of wind-induced load on evacuated tube solar water heaters

Solar Water Heater (SWH) has been used as a traditional device in many countries and regions for collecting solar energy. Unfortunately, there are many wind-induced accidents of SWHs, owing to insufficient consideration of wind-resistant design and installation. To better promote the safe use of SWHs, characteristics of wind load acting on them should be clarified thoroughly as far as possible. In this article, a systematic study is carried out by numerical simulation based on computational fluid dynamics (CFD) to analyze the effects of the tilt angle and density of evacuated tube collectors (ETC) as well as wind direction on the aerodynamic characteristics of SWH. Results show that the wind-resistance performance of SWH decreases significantly for wind flows blowing from 0 degrees and 180 degrees due to the influence of aerodynamic characteristics of its main components. When the ETC is located upstream of the water tank, the arrangement form of the tubes will have an impact on the aerodynamic char-acteristics of the SHW. A lower porosity of ETC can increase wind load on the weak region of water tank and the windward face of vertical supports, it can also increase the bending moment of inclined supports significantly. By contrast, lower tilt angles of ETC are more beneficial to the wind resistance of SHW, although they can result in an increase of the local wind suction on water tank.