Abstract:To solve the problem of low accuracy of the results generated by building daylighting simulations under the generic sky models, this paper attempts to use the on-site measured sky luminance distribution HDR images as the light source to conduct the building daylighting / dynamic daylighting simulation and has validated the method. First, the method of measurement of sky luminance distribution via HDR image is indicated, and the image-based daydaylight lighting / dynamic daylighting simulation (IBL) and the method that uses HDR image as the light source input value in daylighting simulation are introduced and validated. The validation experiments are carried out from: 4th to 10th Jul. and 3rd to 12th Aug. 2017. The interior illuminance and luminance distribution are measured via instruments and meanwhile, the sky luminance distribution (including the exterior environment) is measured simultaneously. After comparing and analyzing the measured and simulated results, the accuracy of HDR image in measurement of sky luminance distribution and image-based daylighting simulation is validated. Finally, the pros and cons of sky mathematical model based daylighting simulation and IBL image based daylighting simulation are discussed. The results show that the sky luminance distribution could be accurately measured via HDR image, the accuracy of IBL simulation results of IBL is well performed, the the errors between simulation and measurement in one instant are concentrated focused within the range of -15%~47%, and the max error of 100 lx < UDI < 3000 lx generated from IBLimage-based dynamic simulation limits within ±25%.