How to get indoor temperature for basement pre-processor?

asked 2022-03-22 14:13:17 -0600

updated 2022-03-22 14:44:09 -0600

Hi all,

I'm using the basement preprocessor to model the ground heat transfer for an existing small building in Energy plus. On the input parameters, I have to input Indoor temperature every month, so that the preprocessor can estimate the heat flux.

How shall I obtain those indoor temperatures?

I have tried running the model with two sets of monthly mean air indoor temperatures: 1) Obtained from a preliminary run considering the surfaces in contact with the ground as adiabatic. 2) Obtained from a preliminary run considering a simplified ground temp of 18ºC

I am comparing the resulting zone temperatures of the simulation with temperature recordings we made in the building (unheated), but none of the options seems to get close enough to give us confidence. One option shows consistent 3-4K above, the other is some 3K below.

I've checked E+ documentation and the Ground heat transfer manuals but it didn't clarify this. Thanks, Rafael

edit retag flag offensive close merge delete



Have you considered using Kiva instead? This doesn't need a preprocessor step in your workflow like the basement or slab tools.

Aaron Boranian's avatar Aaron Boranian  ( 2022-03-22 14:46:22 -0600 )edit

Hi Aaron, Kiva has been on my to-do list for a while, but I never manage to make time and get my hands on it. Since we have automated part of the idf syntax for the Preprocessor, we always find it faster to rely on it.

For the medium term, entirely agree that Kiva would be the solution. But I´m still hoping to find an answer for this one.

rafael.alonso's avatar rafael.alonso  ( 2022-03-23 05:35:45 -0600 )edit

Are the 3-4K differences in zone temperatures at an hourly frequency, or monthly average, or something else? Having the preprocessor calculate hourly loads from a monthly air temperature will make it difficult for hourly model results to match hourly recorded data.

Aaron Boranian's avatar Aaron Boranian  ( 2022-03-23 09:18:47 -0600 )edit

The 3-4K difference was in hourly temperature. We just realised we were comparing Zone Operative to Ambient air recordings which is not really comparable. Comparing Zone Mean Air output to the Air temperature recordings shows values that are much closer, below a 0.5K difference. Solved, apologies Aaron for the initial confusion.

rafael.alonso's avatar rafael.alonso  ( 2022-03-25 04:40:48 -0600 )edit

Ah! Cool, no worries and I'm glad there was a solution.

Aaron Boranian's avatar Aaron Boranian  ( 2022-03-25 17:05:03 -0600 )edit