Design, Construction and Calibration of an Instrument for Measuring the Production of Chilled Water by the Combined Effects of Evaporation and Night Sky Radiation

This paper presents the design and mathematical modeling of thermal radiator panels to be used primarily to measure night sky radiation from dry and wet coated surfaces. Three panels may be used in conjunction as a combined measuring system. One panel consists of an upper dry surface coated aluminum sheet laminated to an ethylene vinyl acetate foam backing block having a pattern of parallel flow water channels and header channels milled into its mating surface prior to lamination to the aluminum sheet. This configuration provides a fin and channel radiator instrument whereby circulating water may be used to measure the heat loss from this panel to night sky radiation. In a second configuration, the surface of a panel without buried water channels but otherwise identical may be wetted in order to study and compare the night sky radiation from its wet surface. In this case, the measuring water is circulated over the upper face of this panel. In a third configuration, water is sprayed onto the surface of the second panel (or a similar panel) so that an evaporative cooling effect is gained in addition to the radiation effect. Initial TRNSYS simulations for the performance of all three configurations are presented and it is planned to use the panels as calibrated instruments for discriminating between the cooling effects of night sky radiation and evaporation. Copyright © 2012 by ASME.

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