2002 Annual

Thursday, 17 January 2002: 9:45 AM
Field Comparison of New Self-Powered Solar Radiation Shield and Naturally Ventilated Multi-Plate Radiation Shield
John D. Crosby, EnviroTech Sensors, Inc., Clarksville, MD
A new radiation shield requiring no external power has been developed to minimize errors from solar heating. The SungardTM Solar Radiation Shield provides improvements over popular non-aspirated designs. Temperature and relative humidity probes are typically installed in non-aspirated multi-plate radiation shields that depend on natural airflow to reduce solar induced errors. As reported by Richardson and Brock, 1999, Tanner et al. 1996, and others, multi-plate shields introduce significant errors due to inadequate coupling with the atmosphere, especially with low wind velocities (<2 ms-1) and high insolation (>700 Wm-2). Tanner et al. 1996 also reported that radiative cooling from the multi-plate shield results in lower than normal temperatures.

Testing of SungardTM against the multi-plate shield has demonstrated not only lower reported temperatures but also a reduction of radiative cooling effects and thermal lag. This paper will examine the characteristics of the new shield, describe the instrumentation and methods, and present an analysis of the test results.

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