[EnergyPlus_Support] Ground temperatures pre-processor

["carlbauer2000" <carl.bauer@xxxxxxx>]

I have looked through other questions on ground temperature and it
seems that for slabs on grade the recommendation is to use the
preprocessor to  determine the ground temperatures under the slab.
These are then the temperatures immediately on the other side of the
slab so I assume I should then not use any ground construction under
the slab.

I did this excercise for a fairly large office building in Gaborone,
Botswana and ended up with temperatures of 23 degrees in summer to
about 19 degrees in winter under the slab. These monthly temperatures
are always within a degree or so of the indoor temperature for the
conditioned building ground floor. However, when I adjust these
temperatures by a few tenths of a degree it has a significant effect
on the heat flows through the slab.

This means that the accuracy of these temperatures is critical. Hence
I was a bit surprised that the standard advice is to use the average
building inside temperature less 2 degrees. This would give a very
large difference in heat flows in my case. Even with the small
difference in temp outside to inside I am getting average heat flows
out through the slab in summer which are about half of the cooling
delivered by the HVAC.

Has anyone else looked into this issue?





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