We deliver precision-driven recalibration for both photovoltaic and thermopile instruments, ensuring your monitoring equipment maintains peak accuracy. Our certified technicians perform meticulous calibrations in the field or lab, helping you maximize plant productivity and maintain compliance with industry standards.
Pyranometers, exposed to harsh outdoor conditions, can experience sensitivity drift over the years. Regular calibration is essential to maintain the accuracy of your solar radiation measurements. Our calibration process involves comparing the measurements from your instrument with those of one or more reference instruments under controlled conditions, ensuring your equipment meets the highest standards of precision.
Accurate pyranometer calibration is fundamental to monitoring the efficiency and productivity of your solar plant. Here's why it matters:
Performance Ratio Calculation: Calibrated pyranometers are essential for accurately calculating the performance ratio, a key metric in assessing system efficiency. The calculation of the performance ratio can be obtained both by relating instantaneous power with irradiance, and by relating the energy produced in a given day with the irradiation of that same day. The latter gives more accurate results. Being optical sensors, they are not free from instrumental drift caused by aging. For the calculation of the P.R, see also the standard EN: 61724-1.
Note: the CEI EN 61724-1 standard defines performance ratio as the ratio between the actual energy yield and the possible theoretical yield.
Contractual Compliance: Many Operation and Maintenance (O&M) contracts use performance ratios to determine premiums or penalties, making accurate measurements crucial.
System Comparison: Properly calibrated instruments allow for fair comparisons between photovoltaic systems in different locations.
Degradation Monitoring: Accurate measurements help track system degradation over time, distinguishing between issues like dirt accumulation and actual panel degradation.
Optimal Decision Making: Precise data enables informed decisions about system maintenance and upgrades, optimizing your solar farm's performance and longevity.
To obtain the precise performance ratio it is important that the measurement of the amount of irradiation (or irradiance) received is as correct as possible. To do this, a photovoltaic or thermopile pyranometer is most commonly used.
For more in-depth information, click the link: Should I use a pyranometer or a irradiance sensor?
Laboratory calibration provides a controlled environment for pyranometer recalibration. While it offers the same high precision as field calibration, it's important to consider the potential downtime for your monitoring system when choosing this option. The choice between lab and field calibration ultimately depends on your specific needs and operational requirements, as both methods ensure equivalent accuracy.
Although more economical, lab recalibration takes more time as equipment needs to be dismantled, shipped and reassembled.
In some cases, it is possible to request a replacement irradiance sensor which can be delivered before disassembling the sensor due for recalibration.
Field calibration offers the advantage of on-site service, minimizing downtime for your solar monitoring equipment. Field calibration is often preferred for its reduced downtime, while maintaining the same level of precision as laboratory calibration due to the use of identical instrumentation.
This type of calibration has the added costs of travel and (potentially) accommodation. With a view to complete transparency, at Soluzione Solare we state all travel and accommodation costs clearly upfront.
Upon completion of pyranometer calibration, we provide comprehensive documentation to ensure you have a clear record of the process and results:
Detailed Calibration Report: A thorough document outlining the calibration procedure, results, and any adjustments made.
Instrumental Drift Annotation: We include notes on any instrumental drift found during the calibration process, helping you track your equipment's performance over time.
Compliance Certification: When applicable, we provide documentation certifying that the calibration process adheres to relevant industry standards and regulations.
IEC 60904 are a set of 9 standards, from IEC60904-1 to IEC60904-10 (excluding 60904-6) implemented by the Italian Electrotechnical Committee (CEI).
The standards relating to production and calibration requirements of photovoltaic sensors are:
– IEC 60904-2 – the requirements for reference solar devices.
– IEC60904-9 – solar simulator performance requirements.
Those related to standards are:
– IEC60904-3 – measurement standards for photovoltaic solar devices, with a reference solar spectrum.
– IEC60904-4 – a procedure for establishing the calibration traceability of reference solar devices.
- IEC60904-4 is fundamental for the traceability to pyranometers, pyroheliometers and thus World Radiometric Reference (WRR).
– IEC60904-8 – spectral response measurement of a photovoltaic device
Pyranometer recalibration times vary depending on the type of sensor:
Thermopile pyranometers, following ISO9847, require at least 2.5 hours for the shortest calibration procedure and up to 2 days for more thorough methods. This longer duration is partly due to the thermopile sensors' slower response time to irradiation changes compared to photovoltaic (PV) pyranometers. However, it should also be considered that the adaptation time of a thermopile pyranometer during sudden variations in irradiation, is 10–20 times longer than that of the most photovoltaic pyranometers. ISO9847 also prescribes a mathematical procedure to determine the correct 'calibration factor' from the measurements made. Finally, the newly adjusted sensor is subjected to a recording of the measurements to verify its correct behavior and the alignment of the measurements returned with the reference sensor. In contrast, Photovoltaic pyranometers can typically be recalibrated in under an hour in the field, not including preparation time. Modern field instruments have improved the efficiency of these procedures compared to older methods. Soluzione Solare's PV pyranometer calibration complies with EN CEI60904-4 standards.
