The Open Solar Outdoors Test Field (OSOTF) is a project organized under open source principles, which is a fully grid-connected test system that continuously monitors the output of many solar photovoltaic modules and correlates their performance to a long list of highly accurate meteorological readings.
As the solar photovoltaic industry grows, there is an increased demand for high-quality research in solar systems design and optimization in realistic (and sometimes extreme) outdoor environments such as in Canada. [1] To answer this need, a partnership has formed the Open Solar Outdoors Test Field (OSOTF). The OSOTF was originally developed with a strong partnership between the Queen's Applied Sustainability Research Group run by Joshua M. Pearce at Queen's University (now at Michigan Tech) and the Sustainable Energy Applied Research Centre (SEARC) at St. Lawrence College headed by Adegboyega Babasola. This collaboration has grown rapidly to include multiple industry partners and the OSOTF has been redesigned to provide critical data and research for the team.
The OSOTF is a fully grid-connected test system, which continuously monitors the output of over 100 photovoltaic modules and correlates their performance to a long list of highly accurate meteorological readings. The teamwork has resulted in one of the largest systems in the world for this detailed level of analysis, and can provide valuable information on the actual performance of photovoltaic modules in real-world conditions. Unlike many other projects, the OSOTF is organized under open source principles.
All data and analysis when completed will be made freely available to the entire photovoltaic community and the general public. [2]
The first project for the OSOTF quantifies the losses due to snowfall of a solar photovoltaic system, generalizes these losses to any location with weather data and recommends best practices for system design in snowy climates. [1] [3] This work was accomplished by creating a synthetic day using empirical data from the OSOTF. [4] [5] This application of the OSOTF has been covered extensively in the media. [6]
This system has been made possible by the Natural Sciences and Engineering Research Council of Canada and contributions and collaborations from:
The development of this test facility is a testament to the commitment of the photovoltaic industry to continuous innovation, and the researchers hope that it will be a valuable tool for ensuring the development of a sustainable power system worldwide. [7]
The SEARC Open Solar Outdoors Test Field consists of two discreet test beds, the largest of which is located on the roof of the new Wind Turbine and Trades building at St.Lawrence College and which has room for 60 commercial PV panels, which are divided between eight angles of 5.10,15,20,30,40,50 and 60 degrees. Live video for the test field is openly available online. Full data access available here.
The second test field is located on a flat rooftop at St.Lawrence College and consists of two commercial flat roof ballasted systems. Live video of this test field is also available online
In addition the Queen's Innovation Park Test Site which was developed as part of a preliminary study on the effects of snow on photovoltaic performance funded by Sustainable Energy Technologies. It consists of 16 panels mounted at angles from 0 to 70 degrees, with two each at increments of 10 degrees. By monitoring panel output, solar influx, snow fall and meteorological factors a loss due to snowfall can be determined for a general system at a variety of angles. In addition, thermal panel measurements lead to a better understanding of snow shedding mechanisms. A series of analysis algorithms have been developed which allow for constant data mining to determine factors such as snow coverage ratio using image analysis, performance ratio, and estimated losses/gains due to snowfall. A detailed description of the sensors and measurements used in the study can be seen below.
The Open Solar Outdoors Test Field is designed to be a state-of-the-art outdoors test facility which makes this site one of the premier PV test beds in North America. The capabilities of this test bed are shown in the following table.
Measurement | Device | Description | Accuracy |
Solar Radiation-Direct | CMP-22 Pyranometer | The highest quality secondary standard device, calibration directly traceable to the World Radiometric Reference in Davos, Switzerland | <1% |
Solar Radiation-Diffuse | CMP-22 Pyranometer | The highest quality secondary standard device, calibration directly traceable to the World Radiometric Reference in Davos, Switzerland, fitted with an adjustable shadow band | <1% |
Solar Radiation-Albedo | CMP-11 Pyranometer | Secondary standard device, calibration directly traceable to the World Radiometric Reference in Davos, Switzerland. | <2% |
Wind Speed and direction | RM-young wind monitor | WMO standard integrated wind speed and direction sensor. | +/- 3 m/s +/- 3 ° |
Temperature/RH | Rotronic HygroClip | Integrated temperature/ RH sensor with radiation shield. | RH: +/- 1.5% Temp: +/- 0.2 C |
Snow Depth | SR50 ultrasonic snow depth sensor | Provides accurate readings of snow on ground using calibrated ultrasonic pulses. Can give total snow depth and accumulation/settling rate. | +/- 0.4% |
Data Acquisition System | Campbell Scientific CR1000 | The industry standard for high-accuracy environmental monitoring. Expanded with multiplexers to accept 106+ point measurements | +/- 0.12% |
Photographs | StarDot NetCam IP camera | High-resolution camera, photographing array at 5-minute intervals. Photos will be used with customized image analysis software to give: Covered area, accumulation rate, sliding rate. | 3 megapixel sensor |
Panel Temperature | Custom T-type thermocouple | Monitoring of panel temperature profiles using Special Limits of Error T-type thermocouple wire. Attached to solid-state multiplexers with integrated cold-junction compensation. | +/- 0.5 C |
Panel Power monitoring | Custom Transducers with MPPT | The panels are monitored using a proprietary DC power transducer, calibrated using instrumentation traceable to NIST. This transducer measures Vmp and Imp at the regular collection intervals. The use of a 99.7% efficient MPPT device ensures that the DC maximum power point of the panel under any real world condition is known | <1% |
Spectral Distribution | Ocean Optics USB4000 Spectrometer | High quality spectrometer allows for monitoring of spectral effects within the range of PV sensitivities. This can be extremely useful when monitoring practical performance ratios and when investigating the effects of Albedo on PV performance | >99.8 % corrected linearity, spectral range 200 nm-1100 nm |
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially utilized for electricity generation and as photosensors.
The National Renewable Energy Laboratory (NREL) specializes in the research and development of renewable energy, energy efficiency, energy systems integration, and sustainable transportation. NREL is a federally funded research and development center sponsored by the Department of Energy and operated by the Alliance for Sustainable Energy, a joint venture between MRIGlobal and Battelle. Located in Golden, Colorado, NREL is home to the National Center for Photovoltaics, the National Bioenergy Center, and the National Wind Technology Center.
A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of photovoltaic modules, known colloquially as solar panels. The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 to 0.6 volts.
A solar panel, or photo-voltaic (PV) module, is an assembly of photo-voltaic cells mounted in a framework for installation. Solar panels use sunlight as a source of energy to generate direct current electricity. A collection of PV modules is called a PV panel, and a system of PV panels is call an array. Arrays of a photovoltaic system supply solar electricity to electrical equipment.
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A photovoltaic power station, also known as a solar park, solar farm, or solar power plant is a large-scale photovoltaic system designed for the supply of merchant power into the electricity grid. They are differentiated from most building-mounted and other decentralised solar power applications because they supply power at the utility level, rather than to a local user or users. The generic expression utility-scale solar is sometimes used to describe this type of project.
Joshua M. Pearce is an academic engineer at Michigan Tech known for his work on protocrystallinity, photovoltaic technology, open-source-appropriate technology, and open-source hardware including RepRap 3D printers.
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