Development of a Method for Evaluating the Influence of Building Facade Form on Its Potential for Solar Radiation Acquisition

Studying the potential of buildings for utilizing solar radiation would be helpful to decrease the energy consumption of buildings. The solar radiation acquisition (SRA) potential of building facades can be used to characterize the building’s SRA potential. A review of the existing literature shows that few performance indicators have been established to specifically evaluate and guide the design of the building facade form from the perspective of SRA potential. This study explores how to evaluate the form of building facades to affect their SRA potential. Two new indicators ( ρ value—the surface density of solar radiation received by the facades—and α value—the correction coefficient for receiving solar radiation in the concave part of the facade) and one new path were constructed to evaluate the SRA potential of building facades. It was found that the ρ values can reflect the upper limit of solar radiation in the region itself and serve as a basis for measuring the building’s SRA potential in the region. It is only related to the shapes of buildings and not to their sizes, and the larger the ρ value of a building, the stronger its facade’s potential to receive solar radiation. The α values can intuitively show the discount of the SRA potential when adding a concave part into the architectural design. At the same time, the extent of the discount due to the elements of the concave part can be elucidated, which can help minimize the loss of solar radiation when designing the concave part in the architectural design process. It is only related to the shapes of building plans (which directly relate to the building facade) but not their sizes. The larger the α value of the concave part of the building facade, the stronger its potential to receive solar radiation. The method for identifying the proper range of ρ values and calculating the standard ρ values was proposed and utilized in Lanzhou city as an example. It reveals that, for Lanzhou city, the maximum ρ value ( ρ max) is 670.98 kwh/m 2 and the average value of ρ value ( ρ ave) is 592.47 kwh, which reflect the basic situation of buildings’ SRA potentials in this city. For the concave parts of the triangular facades in this specific region, the concave offset has almost no effect on their α value. When the concave part of the building facade is triangular, the further south the concave part (rectangular is up to 30° southwest), the smaller the CCS, the higher the concave HWR, the larger the correction coefficient, and the greater the SRA potential of the buildings’ facades.