Pyranometer ventilation unit VU01

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 mitigation of dew and frost and quick evaporation and sublimation of water and snow. ISO/TR 9901 “Solar Energy—Field Pyranometers—Recommended practice for use” recommends the use of ventilators where high accuracy and reliability are required. Enhancing pyranometers and pyrgeometers Ventilation unit VU01 may be used in combination with Hukx’s SR20, SR22 and SR25 Class A 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 Ventilation promotes thermal equilibrium between all components of radiometers, and thereby reduces zero offsets. Deposition of dew and frost are mitigated. 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.