The amount of sunlight that hits the earth in one hour provides more power than the entire world consumes in one year. Photovoltaic cells are required to convert this source of unlimited, clean energy. Solar cells absorb sunlight and convert it into usable electricity through its semi-conductive properties. However, several aspects affect the amount of energy the photovoltaic system receives and the efficiency of the solar cells. In particular, building-integrated photovoltaics (BIPV) have many factors that affect the system’s performance, including the location, elevation, colour of the modules, and orientation.
When utilizing a light-coloured panel, a higher amount of sunlight is reflected than absorbed. The high rate of reflected sunlight will result in lower solar energy generation and lower electricity produced by the BIPV system.
When utilizing a dark-coloured panel, more sunlight is absorbed into the solar cell than reflected off the module—the high rate of absorbed energy results in higher solar energy generation and more electricity production.
Different geographical locations receive different amounts of sunlight, which affects the energy generation of a solar system. The more sun exposure the integrated solar modules receive, the more energy it produces. Sun exposure is generally measured in the annual sunlight hours of a specific geographical location, which is affected by that region’s climatic conditions.
Another aspect regarding the location of the building and its impact on energy generation is shadowing. Suppose a building has many shaded areas; for example, due to other structures blocking sunlight, less solar energy will be generated from the system. At Mitrex, we provide a full shade analysis for every project to ensure that we account for the impact on the system size.
The position of the solar modules on a building is a fundamental consideration for any BIPV system. Different sides of a building receive different amounts of sunlight based on the sun’s orientation. Depending on the photovoltaics’ placement on the building, the incident angle varies, which ultimately affects solar energy generation.
The ideal elevation varies depending on the geographical location. For example, south-facing solar modules in Toronto, Canada receive more sunlight than the north-facing side of the building; however, this may not be the case in another city, depending on the sun’s position. At Mitrex, we account for varying energy production on all the building elevations to provide an accurate system size analysis for our clients.
Total Annual Sunlight Hours2450
Please note: Annual sunlight hours displayed are based on historical averages calculated at verticle angle, factoring in loss due to weather conditions and soiling.
When photovoltaics are oriented horizontally on a building, more energy is being produced by the system because there is more solar irradiation. In comparison, when solar modules are vertically integrated onto a structure, it is capturing less solar energy and therefore generates less electricity. Although the vertical orientation has less solar irradiance, it is still advantageous because this surface area would otherwise produce zero electricity.
The ideal orientation for building-integrated photovoltaics is a tilted angle towards the sunlight, as this maximizes the area of absorption on the solar modules.