Solar loading on the external surfaces of external boundaries

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  • Last Post 07 January 2019
szhang posted this 07 January 2019

Hello,

 

I am trying to make a shoebox building zone that consists of a south-facing window, and the domain is subjected to solar radiation. In this model, there is only one domain presented. As you can see, solar loading is only present on the inner surface of the walls where the solar ray enters the domain and land on the opaque surface. However, the exterior surfaces, the side that faces the do not receive any solar radiation. The walls have been set to shell conduction. I want to simulate the solar loading on the external walls so that I can take into account the effect of solar radiation being absorbed by the external surfaces and the absorbed heat is then diffuse inward.    Does anyone know how to set it up so that the external surfaces are also subject to solar loading?

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rwoolhou posted this 07 January 2019

The solar load model is designed to dump energy into the domain based on the sun position etc and only allows energy in through semi-transparent boundaries. Ie the image above shows it's working as intended. 

If you want to add an energy gain due to solar load on the other surfaces you'll need to manually add that via heat flux to the opaque walls. 

szhang posted this 07 January 2019

Thank you. May I know if 1) I should use UDF to achieve this, and 2) it is possible to add an energy gain via heat flux based on the data obtained from the solar calculator? 

 

 

rwoolhou posted this 07 January 2019

I'd just add a heat flux and not bother with the UDF as it's a single value. 

szhang posted this 07 January 2019

Thank you. May I know what should I do if I want to use the heat flux data from the solar calculator? I would like to do a transient study and it might be impossible to calculate the heat flux by hand and apply them for every iteration.

So, do you know if ANSYS supports exporting data from the solar calculator model?

 

Thank you.

abenhadj posted this 07 January 2019

A (not the unique) Workaround for external opaque wall Set all external walls to semi-transparent, set absorptivity and transmitivity to zero and initialize to get the solar fluxes. Deduce from it the temperature, export that Temperature as Profile which can be used for the opaque external temperature (Mixed boundary condition)

Best regards,

Amine

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