Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Revision history [back]

click to hide/show revision 1
initial version

Below-grade Question Heat Transfer Question

Hi all, I have a quick question and would really appreciate some feedback/guidance.

I am currently working on a building that is entirely below ground in Saudi Arabia. We have data to suggest that the temperature will be a constant 27 degrees Celsius, once you’re about 4m deep. I am tasked with identifying if they need insulation.

What I am a bit confused about is, if I am setting the exterior wall temperature 27degrees, do I still account for the ground resistance of the ground + the walls? - doing so would obviously improve the u-values of the walls, and provide further protection from the 27 degrees, but that makes no sense to me, since the ground itself is already 27 degrees. So logically to me, the ground resistance should not be providing any benefit to the wall resistance, since it’s already 27 degrees.

Or should I just account for the ground resistance, and ignore below ground temperatures?

Obviously if I treat the walls like regular walls and not account for the ground resistance, the results show that there is a need for insulation. Where if i account for the ground resistance, obviously that u-value is significantly improved, and therefore there is no need for insulation.

I know that in the region they typically don’t insulate below ground structures, don’t really understand why.

Would love some feedback and thoughts on the matter.

Thanks in advance,

Mony

Modeling Below-grade Question Heat Transfer Question

Hi all, I have a quick question and would really appreciate some feedback/guidance.

I am currently working on a building that is entirely below ground in Saudi Arabia. We have data to suggest that the temperature will be a constant 27 degrees Celsius, once you’re about 4m deep. I am tasked with identifying if they need insulation.

What I am a bit confused about is, if I am setting the exterior wall temperature 27degrees, do I still account for the ground resistance of the ground + the walls? - doing so would obviously improve the u-values of the walls, and provide further protection from the 27 degrees, but that makes no sense to me, since the ground itself is already 27 degrees. So logically to me, the ground resistance should not be providing any benefit to the wall resistance, since it’s already 27 degrees.

Or should I just account for the ground resistance, and ignore below ground temperatures?

Obviously if I treat the walls like regular walls and not account for the ground resistance, the results show that there is a need for insulation. Where if i account for the ground resistance, obviously that u-value is significantly improved, and therefore there is no need for insulation.

I know that in the region they typically don’t insulate below ground structures, don’t really understand why.

Would love some feedback and thoughts on the matter.

Thanks in advance,

Mony