[ranasa]

Hi guys I am stuck and I could really use some help

i try to model a PCM tube heat exchanger inwhich an annulus holds cool air flowing inward and the outer part of the annulus filled with liquidized PCM. the cool air gets warmer as the PCM loses heat and gradually changes phase to solid. the HE is in free convective heat transfer with the surrounding air.

the whole system is exposed to the sunny condition, and the radiation between surrounding air and the PCM (and the inner air, as well) will effect the heat transfer quality and quantity both. we want to observe this effect in both Charge and Discharge processes of PCM (the charging trend comes with the vice versa initial condition mentioned above)

here is the question, which Radiation Model i should activate and how to insert the required properties that comes up with the application of radiation?

i have already tried DO method, but no idea for the continuation. is it needed to activate solar load?

Any help would be appreciated;
Thanks in advance

Rana