Rain Flag - Exterior Convection Coefficient is 1000
Posted by Michael J. Witte, Last modified by Michael J. Witte on 28 November 2017 07:18 PM
What is the meaning of 'Surface Ext Convection Coeff' report returned as 1000? I seem to remember that it means rain and this seems to be confirmed by weather data but what is the heat transfer coefficient in this case? or does rain mean some other mechanism is used?

From the Engineering Reference, Outdoor/Exterior Convection section (v3.0.0.023, pdf p. 79):

"Note that when the outside environment indicates that it is raining, the exterior surfaces (exposed to wind) are assumed to be wet. The convection coefficient is set to a very high number (1000) and the outside temperature used for the surface will be the wet-bulb temperature. (If you choose to report this variable, you will see 1000 as its value.)"

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