Discussion Forum

Dear reader,

I am trying to model a so-called hot-box apparatus, which consists out of a hot chamber with an adjacent specimen frame, holding a solar panel. The hot chamber is an insulated box that is open on one side, which is sealed through the solar panel to be measured. The hot chamber consists of an internal room filled with air, which will be heated to a temperature of 70 degrees Celcius. The hot box is insulated to prevent heat losses through the walls to the environment. It is intended to stimulate a heat flux from the heated air through the solar panel to the surrounding environment. The entire hot-box apparatus will be placed inside an airconditioned room and kept at a steady 20 degrees Celcius. The internal warm air (inside the hot chamber) will initiate a heat flow through the solar panel. This will cause the solar panel to warm up and thereby it takes on a temperature when steady-state conditions are reached. The temperature of both the solar panel's surfaces needs to be estimated utilizing this model. With the help of these temperatures, the temperature difference across the solar panel can be determined and used to calculate the panel's U-value.

However, I have not been able to model the internal natural convection of the heated air upon its surrounding surfaces (insulated walls and the solar panel). I have attached the model in the hope of some help from you guys, I would appreciate it!

For now, I have modeled the internal air cavity as a solid block (block 11 - geometry tree). I need to find a way to model the heat transfer from the heated air inside the hot box through the solar panel and the insulated walls. I have tried many different things, however, seem not to be able to find the right configuration.