Round-Robin test of calibration accuracy for different methods and sites
Creators
- 1. DLR
- 2. CIEMAT
Description
Solar radiation resource assessment is crucial for potential solar power plant sites. Site selections with inadequate resource assessment could result in complete economic project failures. Accurate solar resource data can be gathered by thermopile based sensors like pyrheliometers for direct normal irradiance measurements (DNI) and pyranometers for direct global and diffuse horizontal irradiance measurements (GHI and DHI respectively) as specified in [ISO 9060]. Pyrheliometers and pyranometers used for DHI measurements require a sun tracker which follows the course of the sun. The correct alignment of the sensors on the tracker and the tracker itself is essential. Usable data can only be obtained, if a periodic and frequent cleaning procedure of the sensors is guaranteed [Geuder, Quaschning, 2006]. This maintenance demand could cause increased cost especially for remote locations.
Semiconductor based Rotating Shadowband Irradiometers (RSI), which measure DNI, GHI and DHI are less affected by soiling [Geuder, Quaschning, 2006] and do not require a solar tracker. Furthermore, a small PV solar panel is sufficient for the electrical supply of a RSI. Thus RSI are the preferable choice for long term measurement campaigns on remote sites where daily cleaning is not feasible, despite their lower accuracy when compared to well-maintained thermopile based sensors.
However, a thorough calibration is required which must consider also the correction function for systematic errors caused by its spectral non-uniform responsivity, cosine-response as well as temperature effects. This report presents the results of a round robin test conducted calibrating a single RSI according to different methods described in [Jessen et al., 2017] at the Plataforma Solar
the Almeria (PSA) and at an additional CIEMAT test site facility in Madrid and discusses the possible reasons for any detected deviations. After a short description of the calibration setups in section 2, the evaluation method is described in section 3. Then results are presented in section 4 and finally conclusions are summarized.
Files
SFERA-II_D11.4_Round robin test for RSI-v2.pdf
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(486.2 kB)
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