Integration Design And Optical & Thermal Study Of Dynamic Concentrating Solar Building Skin

Currently,sustainable design has become the dominant methodology.Building skin is developing towards the directions of ecological,environmental responsive and dynamically adjustable.Solar energy is abundant and easily obtained.Concentrating solar technology is one of the advanced solar energy utilization approaches.The aesthetic appearance,structure and energy production characteristics of building skin will be changed if the concentrating solar technology is integrated.In view of the existing problems in research and application of Building Integrated Concentrating Photovoltaic(BICPV),there are three key issues need to be addressed for BICPV namely modular design,dynamic structure and optical & thermal characteristic.In this paper,a new type of high magnifications transmissive solar concentrating module is designed which is suitable for building integration that using Fresnel lens as concentrator.And real model in accordance with the design parameters is created and tested in electrical performance by experimental studies.A new dual-axis linkage system is designed to realize the dynamic integration for BICPV with joint bearings as the control nodes.The optical analysis software Trace Pro is used to quantitative study the optical efficiency of the high magnifications transmissive solar concentrating module under different incident conditions and impact rate of indoor daylighting for BICPV.Thermal characteristics of the concentrating assembly is studied under different conditions by computational fluid dynamics software ANSYS-CFX.The experimental results of the electrical performance of the concentrating module show that the efficiency of direct light collection is about 65%,and the module has a stable power output ability under continuous operation.The simulation results of optical characteristics for concentrating module show that the light receiving efficiency remains above 76.87% if incident light deviation is within 1°.Taking the Tianjin area as an example,the impact rate of daylighting is between 9.13% and 11.66%when concentrating array is under working state on sunny days,the impact rate is 6.58%to 8.36% in the non-working on sunny days,and the impact rate is 5.97% on overcast days.The simulation results show that active ventilation can effectively reduce the temperature of the concentrating assembly under working conditions.The Heat dissipation efficiency from the bottom of the module is better than from the side or the top.When the concentrating array is integrated between the double glazing with mechanical ventilation,the modules close to the air inlet have the better heat dissipation efficiency than others.The heat dissipation efficiency from bottom is better than from the top under the same wind speed.When concentrating array is under natural ventilation,heat dissipation efficiency under the type of external open is better than the type of fully open.When wind speed is small,increasing wind speed will reduce the temperature of concentrating assembly significantly.When wind speed exceeds 3 m/s,increasing the wind speed won’t reduce the temperature of concentrating assembly significantly.The research results of this paper can provide design guidance and data foundation for related research and application of BICPV.