Hello,
we are currently working on an energy model. The building we are modelling contains a heat sink for cooling loads within the sprinkler tank, which we can't model with our simulation program. To benefit from the savings the heat sinks will generate, we want to use the exceptional calculations method. Here comes the problem:
According to appendix G2.5 the exceptional calculation needs to include:
c. A sensitivity analysis of energy consumption when each of the input parameters are varied from half to double the value assumed
d. the calculations shall be performed on a time step basis consistent with the simulation program used (which means hourly values during a year)
The way we see it, the exceptional calculation is basically another dynamic simulation. Since our simulation software can't model the heat sink properly, we are kind of stuck.
Any thoughts will be much appreciated!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 29, 2019 - 9:48 pm
Can use use another piece of software?
However you do the calculations you will need to justify them thermodynamically.
Benjamin Weise
CSD Engineers16 thumbs up
October 31, 2019 - 3:40 am
Thanks for your response! I am not entirely sure what you mean by thermodynamically justified: Do you mean hourly calculations or any calculation determining thermodynamic losses/savings?
Is the level of detail needed really the same as in the energy simulation itself? (i.e. hourly calculations plus varying the input parameters from half to double?)
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 31, 2019 - 3:56 pm
You are going to need to calculate savings that will be impacted by multiple building systems. SO the calcs should take them all into account or you will need to demonstrate that the calculations are somehow conservative.
If you wish to capture all the savings I am not sure how you do that without a significant level of detail as in an hourly simulation. If you are okay with just capturing a portion of the savings then another method may suffice. Again you will need to provide a justification for the calculations and not just the calculations themselves.
Benjamin Weise
CSD Engineers16 thumbs up
November 1, 2019 - 3:56 am
Okay, I suppose we'll give it another thought! Thanks a lot for your input!