This is the same as the module nameplate rating loss in the system loss settings, representing the loss due to inaccurate specification of the STC rating of a module. Because the panels are not operating at STC over the course of the year, the energy produced will be lower than the “energy after PV conversion” described above. Aurora performs a full circuit simulation of the design, adjusting the equivalent circuit parameters of each module (or cell string for submodule simulation) according to the irradiance and temperature on a module at a given hour (more information the model we apply can be found here). This is the first loss in the DC category, representing the energy lost due to the modules operating at varying irradiance and temperature conditions throughout the year. This is the “input” to this category; it represents how much energy a design could produce given the incident irradiance (the last value in the ‘Irradiance’ section of the loss diagram), the efficiency of the modules, and the area of the modules: E = S × Σ(ηA), where S is the irradiance in kWh/m 2, η is the maximum module efficiency (usually at STC), A is the area of the module in m 2, and Σ represents the sum of ηA for all modules in the design. This category breaks down all the losses in DC energy, or in other words, all electrical losses that occur on the input side of the inverters. Aurora’s model is based on Snell’s and Bougher’s physical laws; more can be read about it here. The loss given here represent the optical losses in transmission of the light through the module covers. The angle of the irradiance on a solar panel is typically not perfectly normal to the panel, meaning the light comes in at some angle. The snow loss that is applied is equal to the value given in the system loss settings (or values, if given monthly). This is the loss in irradiance due to snow covering the modules. The soiling loss that is applied is equal to the value given in the system loss settings (or values, if given monthly). This is the loss due to soiling (dirt, sand, etc.) on the modules. Aurora’s integrated shading engine computes these losses directly and quantifies them here; if you run a simulation with the shading engine disabled, the loss you see here will be whatever shade derate you provide in the system loss settings. Trees, obstructions, walls/roofs, and other modules can cast shade on an array and reduce the overall irradiance. This is the loss of irradiance caused by shading. Designs with flush modules in a flat rooftop, for example, may show a higher percentage loss than designs with modules tilted by 20-30°, depending on the location of the site. This is the first loss in the diagram; it represents how much of the potential irradiance is not captured by the solar panels due to the way they are oriented and tilted. This is the “input” to the loss diagram; it is the maximum annual irradiance that could fall on the modules if they were tilted and oriented optimally for the location. It covers environmental losses as well as losses due to suboptimal tilt and orientation. This category shows the losses in irradiance on the modules in a design. Aurora's system loss diagram is a breakdown of system losses, showing exactly how much energy is lost at every stage of a design.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |