The CM121 Shadow Ring is designed to be used with any Kipp & Zonen pyranometers, smart pyranometers, pyrgeometers or UV Radiometers to shield the sensor from direct radiation. The combination of one of these sensors and the CM121 offers a simple solution to the problem of measuring diffuse radiation from the sky. Naturally, the ring will also intercept some of the diffuse radiation from the sky. The ring has a width/diameter ratio of 0.185 and has a view of 10.6 seen from the sensors. Therefore, a correction table is provided along with the CM121 to allow for compensation of the intercepted radiation.
Features
The combination of a CM 121 shadow ring and a pyranometers, smart pyranometers, pyrgeometers or UV radiometers offers a simple solution for the measurement of the diffuse solar radiation. The specific advantages of this type of shadowing are that it is suitable for installation anywhere on earth (contrary to designs that require the specification of a particular latitude), that it can be combined with a ventilation unit, and that it has a special U-profile ring which simplifies the mathematical correction for intercepted diffuse radiation.
The shadow ring will keep the pyranometer in the shade during the entire day, preventing the direct solar radiation to reach the sensor. As a result only the diffuse solar radiation is measured. A regular schedule of maintenance would require manual adjustment of the sliding bars (that are connected to the actual shadow ring) every two or three days. This adjustment is necessary because the elevation of the solar course changes slightly from day to day. For proper setting of the sliding bars, the table of “correction factors and the sliding bar setting” can be consulted.
Normally, the sensor will be in the horizontal position but the CM 121 allows for it to be mounted in tilted positions along the north-south axis. The ring itself is equipped with a special U-profile so that it has a nearly constant view angle during the year. A stable stand is also guaranteed even at high winds. The shadow ring will intercept a proportion of the diffuse sky radiation and any measurements should be compensated by using the correction factors provided with the unit.
Specifications
| Materials: | Anodized Aluminium of seawater proof quality Stainless Steel |
| Outer Ring Diameter: | 620mm |
| Ring Width: | 55mm |
| Ring Width/Ring Radius Ratio: | 0.185 |
| View Angle: | 10.6° (apparent width from pyranometer) |
| U-Profile Shadow Ring: | defines the accuracy of the view angle constant within ±2% |
Associated Research Paper
Univesidade de Lisboa, Portugal – Development of a Multiple Orientation Solar Radiation Sensor
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0346901
£3,198.00
0346900
£2,604.00
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