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DR20-A1 pyrheliometer

DR20-A1 pyrheliometer
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Thermal Sensors DR20-A1 & DR15-A1 Analogue spectrally flat Class A & B pyrheliometers, with heating DR20 and DR15 are high-accuracy direct (normal incidence) solar radiation sensors, or pyrheliometers. DR20 complies with the Class A, and DR15 with the Class B specifications of the ISO 9060:2018 standard. These instruments are used in tracker-mounted operation, and offer analogue millivolt outputs. Both pyrheliometers have superior window heating that leads to high data availability. Introduction Hukseflux model DR15 pyrheliometer is an ISO 9060 spectrally flat Class B (old ISO classification “first class”) instrument. It replaces the models DR01, DR02 and DR03. DR20 is a new Class A instrument. It has a better temperature response than DR15. Both instruments offer the highest accuracy and highest data availability, featuring window heating at low offsets. At the same heating power, the heating has been improved with a factor 4, at a 4 times lower offset! Figure 1 DR20 Class A / DR15 Class B pyrheliometer: the external housing of these instruments is identical. DR20 and DR15 are applied in high-accuracy measurement of the solar radiation received by a plane surface from a 5 ° full field of view angle. This quantity, expressed in W/m2, is called “direct” solar radiation or DNI (direct normal irradiance). It is necessary to keep the instrument pointed at the sun by using a two-axis tracker. Heated for high data availability High data availability is attained by heating of the front window. This suppresses dew and frost deposition at a very low power consumption: DR20 / DR15 needs only 1 W to keep its window free from dew and frost. Liabilities covered: test certificates As required by ISO 9060 for Class A classification, each DR20 is supplied with test results for the individual instrument: • • • sensitivity response time temperature response DR15 certificates include sensitivity and response time only. Figure 2 the importance of heating: tracker-mounted operation of heated DR15-A1 and DR20-A1 pyrheliometers, here being installed with heated SR15-A1 pyranometers. The data availability of non-heated instruments suffers in almost all environments due to morning dew and frost. DR20 and DR15 use A pyrheliometer is used in tracker-mounted operation. DR20-A1 and DR15-A1 can be connected directly to commonly used data logging systems. They offer analogue outputs in the millivolt range. Copyright by Hukseflux. Version 1906. We reserve the right to change specifications without prior notice Page 1/3. For Hukseflux Thermal Sensors go to www.hukseflux.com or e-mail us: info@h

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Thermal Sensors The pyrheliometer features a precision ground and polished quartz window, a compact sized collimated tube and a thermopile sensor with black coated surface. 5 6 Figure 3 overview of DR20 / DR15: (1) sights, (2) aperture tube, (3) protection cap, (4) window assembly with heater, (5) connector, (6) cable solar energy surveys solar resource assessments meteorological networks sites with dew and frost problems Uncertainty evaluation direct solar radiation spectrally flat pyrheliometer DR20: Class A DR15: Class B Calibration uncertainty < 1.2 % (k = 2) Heating included Heater 1 W...

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steady state offset [W/m²] heating power [W] Figure 6 the offset of the latest models DR20, DR15 (and also the digital DR30) when heating, is much improved relative to the older DR01, DR02 and DR03 models. DR20 and DR15 have a 12 VDC, 1 W heater which produces a negligible offset. The older models had offsets of the order of 1 W/m2 at the same heating level. In addition, the temperature of the front window of DR20 and DR15 is 4 times higher than that of the older models, at the same heating power. time [hh:mm] DR30 with heating Figure 7 comparison of the measured data with and without...

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