Abstract — In this paper, we explore a rotating shadow band (RSB) configuration for the EKO MS-711 spectroradiometer to measure the global, diffuse and direct components of spectral irradiance. An RSB configuration allows lowering the costs associated with the instrumentation and maintenance required to measure the components of spectral irradiance. Since only one spectroradiometer is used for the measurement of the spectral irradiance components, discrepancies associated to sensor calibration can be minimized. This work presents a study to validate the EKO RSB spectroradiometer accuracy in measuring the direct normal irradiance (DNI). A comparison is made between the measurements performed with the RSB spectroradiometer and a collimated spectroradiometer in Mauna Loa Observatory. The results of the comparison show an agreement within 2% to 5% between the DNI estimated by the RSB and collimation configurations for solar zenith angles smaller than 70°. Larger deviations approximated to 10% are found for larger angles of incidence.

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EKO has teamed up with RainWise to provide the first multi-functional component-based professional weather station, explicitly designed for monitoring PV efficiency, the PVmet 500.

In compliance with IEC-61724-1, the PVmet 500 is a cost-effective, durable weather station capable of measuring wind speed & direction, ambient temperature, relative humidity, rainfall, photovoltaic panel temperature and irradiance in real-time, transmitting sensor measurements to a data logger or data center.

The PVmet-500 is ideal for monitoring the efficiency and performance of a PV plant. Data from the PVmet 500 can be used to obtain vital information concerning the operation of a PV plant and insights on where improvements can be made to increase the PV plant output.

Read the full article published in the PES magazine / September 2018

Maybe you have heard about the upcoming revision of the ISO 9060:1990? Soon the new ISO 9060 standard will be released, replacing the existing ISO standard issued in 1990 concerning the classification of instruments for measuring solar radiation. Significant changes and improvements are expected.  

At this stage, the details of the new ISO 9060 were disclosed within the Final Draft International Standard (FDIS). The draft has been distributed to all ISO committee for a final vote. Once the final draft has been approved, the second edition of ISO 9060 will be published before the end of the year.

Since EKO joined the ISO/TC180/SC1 committee, we have been fully aware of the upcoming revisions and have had an active contribution during the revision process. For EKO it is essential that the new standard will reflect up-to-date specifications based on the progress we made by implementing our latest sensor technologies such as the fast response and the spectrally flat of MS-80 and MS-57. In addition, it is important to make sure the new ISO 9060 becomes a hands-on document for best measurement practice and usability. 

Although we know about the details outlined in the new standard, due to the ISO confidentiality restrictions we cannot disclose detailed information about the standard yet. Nevertheless, all EKO sensors that comply with the ISO 9060:1990 will be fully compatible with the new standard in all aspects.

Thanks to the initiative and contribution of many people working in the solar energy and meteorological research industry, the new ISO9060:2018 will become a comprehensive document for solar radiation measurement practice. 

We look forward to the date of final approval and meanwhile will keep you informed.       

EKO product management
 

We took a different approach to measure the three irradiance components (DNI, GHI, DHI). A spectroradiometer with rotating Shadow Band (RSB) is an attractive alternative to a conventional 3 component sun tracker system. Just one spectroradiometer used for all measurements lowers the costs associated with the instrumentation required. Accurate DNI measurements can be obtained from a MS-711 Global spectroradiometer with RSB comparing with the MS-711 DNI spectroradiometer on a sun-tracker. The comparison between the outputs spectral DNI from the two configurations reveals a consistency in the method and the measuerements of all 3 irradiance components. EKO will provide the RSB solution for all spectroradiometer models.

Discover the new 2018 product guide including several new products. The pyranometer line up with MS-40 and MS-60 pyranometers with analog and digital interface. 

EKO’s new solar Monitoring System, the STR-21G-S0/ S1 and S2, are turnkey sensor systems for the most accurate solar radiation measurements of the direct solar radiation component. It can be easily integrated to any DAQ system, which has multiple analog or digital inputs.

Designed to withstand all weather conditions, the ASI-16 All Sky Imager features a digital camera and fish-eye optics with a 180° field of view assembled under a robust coated quartz dome, avoiding sensor degradation due to direct exposure to the sun and allowing the automated acquisition of high dynamic range (HDR) images of the hemispherical sky. 

The standard ASI-16 Sky Imager is capable of operating under harsh environments from temperatures as low as -40°C up to 50°C, with an integrated ventilation and heating system, which also prevent condensation on the dome surface and promote the fast removal of raindrops and snow. Furthermore, the imager is powered over ethernet (POE), with a durable and waterproof cable. The users can have full control of the imager to perform settings, data acquisition, visualization, and storage, with a web browser-based manager with live video stream and network storage.

The Sky imager is complemented with the Find Clouds software, in which the images acquired with can be processed to classify cloudiness. Using different algorithms to calculate cloudiness, the cloud analysis software, allows the calculation of the sun position in the image as well as to run algorithms such as the blue/red and blue/green channels ratio (BRBG), and the cloud detection and opacity classification (CDOC), to quantify cloudiness on the image set. 

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Download here the article published in PES S1 18