SDR-1 Single Detector Rotating Shadowband Radiometer

The SDR-1 Single Detector Rotating Shadowband Radiometer is identical to our standard Multifilter Rotating Shadowband Radiometer (MFR-7) except that it has a single cosine-corrected broadband silicon channel that provides fully automatic measurements of global, diffuse, and direct normal components of solar radiation. It is very similar to bolometric/thermopile type radiometers except the spectral response of silicon does not extend as far into the mid infrared. Historically, a total solar pyranometer has been integrated with a solar tracker-mounted normal incidence pyrheliometer and a third shaded pyranometer to make these measurements, as is done in the Baseline Solar Radiation Network. However, the SDR-1 offers a simpler and less expensive alternative than these separate instruments. Because it uses only one detector to make all three measurements, there is only one calibration necessary. In addition, because it uses only one mechanical axis of rotation it tends to stay in alignment with the sun much better than a two axis tracker, reducing labor required to operate the system.

SDR-1 SINGLE DETECTOR ROTATING SHADOW BAND RADIOMETER

General Description

The SDR-1 single detector rotating shadowband radiometer is similar to the Multifilter Rotating Shadowband Radiometer (MFR-7) but without the six narrow band filter-detectors. It has a single cosine-corrected broadband channel that provides fully automatic measurements of global, diffuse, and direct normal components of broadband solar radiation. It is functionally equivalent to a total solar pyranometer integrated with a solar tracker-mounted normal incidence pyrheliometer and a second, shaded pyranometer. Because a single detector is used to make all three measurements, calibration problems commonly suffered by traditional three-detector (pyrheliometer/pyranometer/shaded pyranometer) systems are eliminated.

In addition to being much less expensive, the SDR-1's simple single-axis rotating shadowband is operationally much less trouble than two-axis solar trackers. This solar pointing reliability results in data that will be statistically more accurate than data taken by traditional trackers that periodically encounter random errors due to solar disc misalignment. The SDR-1 is hence a better choice for long term unattended global, diffuse, and direct-normal broadband solar irradiance measurements.

The SDR-1's integrated YESDAS-2 control and data logger system easily connects up to analog humidity, temperature, and wind sensors. It accommodates up to 30 analog inputs through which to monitor, for example, PV array voltages. It also offers some of the most stable timekeeping in the industry, including executing ephemeris calculations to locate the sun according to time of day and year, and longitude and latitude. YESDAS essentially knows when the sun is up and stores the current solar zenith angle with every record. SDR-1 systems can be factory-upgraded to MFR-7 systems in the future as your needs grow. Please see the MFR-7, YESDAS-2, and YESDAS Manager datasheets for details on the MFR family and support software.


SDR-1 Detector Assembly