VU01
2Pages

Catalog excerpts

Thermal Sensors Ventilation unit for SR20 and SR22 pyranometers and IR20 pyrgeometers VU01 is a high-quality ventilation unit for use with pyranometers and pyrgeometers. Its purpose is to improve the dependability of the measurement. Measurement accuracy improves because offsets are reduced. Reliability benefits from prevention of dew and frost formation and quick evaporation and sublimation of water and snow. ISO/TR 9901 “Solar Energy - Field Pyranometers - Recommended practice for use” recommends use of ventilators where high accuracy and reliability are required. Introduction Ventilation unit VU01 may be used in combination with Hukseflux’ SR20, SR22 and SR25 secondary standard pyranometers and IR20 and IR20WS research grade pyrgeometers. VU01 provides an airflow over the instrument body and dome and has two heaters on board to heat the air. The use of heating (5 W or 10 W) is optional. The VU01 ventilation unit runs on 12 VDC voltage. Improved measurement dependability Figure 1 VU01 ventilation unit with pyranometer SR20 Ventilation promotes thermal equilibrium between all components of radiometers, and thereby reduces zero offsets. Dew and frost formation is prevented. Additional heating will promote evaporation of water droplets and sublimation of snow. It should be noted that heating in combination with pyranometers will lead to increased thermal offsets, so heating is only recommended if necessary. Maintenance / cleaning Ventilation is typically used with high accuracy measurement requirements. In such cases the need for a high level of instrument maintenance and dome cleaning still exists; evaporating droplets of water might leave stains on the instrument domes. The bottom of VU01 provides access to the removable dust filter. Figure 2 overview of VU01 with SR20: (1) SR20 cable, (2) SR20 connector, (3) SR20 dome, (4) VU01 cover, (5) fixation of cover, (6) levelling feet, (7) VU01 filter retainer, (8) VU01 ventilator, heaters and filter replacement system (below cover), (9) VU01 cable and cable connector, (10) VU01 connector Using VU01 is easy. The ventilator is generally used continuously; the heater is typically controlled by the datalogger. ISO/TR 9901 “Solar Energy - Field Pyranometers - Recommended practice for use” recommends use of ventilators where high accuracy and reliability are required. More details can be found in paragraph 5.2.2 and annex A. The Baseline Surface Radiation Network, BSRN, recommends ventilation for radiometers in its BSRN operations manual v2.1. Copyright by Hukseflux. Version 1610. We reserve the right to change specifications without prior notice Page 1/2. For Hukseflux Thermal Sensors go to www.hukseflux.com or e-mail us: info@huksef

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Thermal Sensors VU01 design VU01 is designed, using high-quality materials, in agreement with the recommendations of ISO/TR 9901 and BSRN. The footprint of VU01 is small, which prevents accumulation of snow. The ventilator power is relatively high in order to increase the airflow. The heaters should be activated using external relays. A fan status signal (high / low) may be used by the user to monitor rotation of the fan. PV system performance monitoring scientific meteorological observations extreme climates (tropical / polar) Choosing the right instrument Pyranometers are subject to...

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VU01 2Pages

Catalog excerpts

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VU01
2Pages