# Parametric analysis/modeling and Live analysis/modeling

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Hello all,
I am having a hard time understanding the concept of parametric analysis/modeling and Live analysis/modeling. I am sorry to say that Google is not very helpful here. I would appreciate if anybody here would explain these concepts to me. Thanks in advance.

Diwanshu Shekhar

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Hi Diwanshu,

Since you are posting to this group I am going to give an example related to buildings. Let me start with modeling. You can mathematically model the physic of heat transfer in a building. This is generally referred to as modeling. The advantage of this is that you can simulate the heat transfer in the building without actually have to build it or build a scale model. The inputs of the building model such as window solar heat gain coefficient etc. can be varied within some constraints to determine the disadvantage/advantage of that on the building energy consumption thereby optimizing the building to consume the least amount of energy. The varying of window solar heat coefficient in the above example would be referred to as parametric analysis. This is a simplistic yet time consuming methodology of optimizing the building energy efficiency feature.

Hope this helps.

Haider Khan.

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Hi Diwanshu,

Just to expand on Haider's message, parametric analysis is applied to a base building design to see the effect of changing (usually one or 2) design parameters on a particular performance variable. The results are plotted as a curve or a series of curves to illustrate the variation graphically. For example, you might be interested to know the effect on building carbon emissions of varying the amount of glazing in the building and you might want to know this for 3 different types of glazing. The graph below was generated by DesignBuilder using the EnergyPlus simulation engine by selecting the parameters to vary. Because glazing provides both benefits (heat in winter and light) and penalties (cooling load), parametric analysis can give useful insights into the relationship between the design parameters and a chosen performance parameter (annual carbon emissions in this case). In the example graph below there is a minimum carbon emissions at just below 80% glazing and this might help guide an architect at early stages of the design process towards a basic optimised configuration.

Andy

[cid:image001.jpg at 01CB02FA.3E6902A0]

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Working on a project that has a couple of floors shelled (unconditioned) for future expansion. We are running an energy model for LEED certification.
?
Should we include those floors for the EAc1 submittal, or can we build our model to exclude those floors? The floors are around 20% of the total building square footage

Vikram Sami
?

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You have to simulate them as built-out floors using default office
occupancies, LPD, equipment, etc, along the guidelines for C&S modeling.

David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, HBDP

*From:* bldg-sim-bounces at lists.onebuilding.org [mailto:
bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Vikram Sami
*Sent:* Thursday, June 03, 2010 10:45 AM
*To:* bldg-sim at lists.onebuilding.org
*Subject:* [Bldg-sim] Modelling Shelled spaces

Working on a project that has a couple of floors shelled (unconditioned) for
future expansion. We are running an energy model for LEED certification.

Should we include those floors for the EAc1 submittal, or can we build our
model to exclude those floors? The floors are around 20% of the total
building square footage

*Vikram Sami*

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Andy and Haider,
This makes a lot of sense now. Thanks to both of you. Now, I am wondering about the live modeling. What is it and how is it different from the parametric runs? Thanks much,
-Diwanshu

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Generally, I think you run them with baseline HVAC unless you have a
central system that future tenants can "plug into".

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Or if a performance specification for fit out exists then go with that.

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Diwanshu,

Good question. Parametric modeling can be just about anything you need
it to be. To me, it means a model that has one or more variations of
some parameters that you want to quantify the differences between. For
example, comparing annual heating and cooling energy use for a building

It's never an idealized optimization, but if you know something about
building science and the desires of your client/architect, it's a good
way to demonstrate the impact of changing whatever design parameters
you're studying. The tricky part is knowing what parameters to change
and how.

*Cramer Silkworth

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I believe my take away is: Modeling of an existing building where you can verify against actual
performance is referred to as "Live Modeling" (as explained by b.fountain). Parametric modeling has to do with when you change one or more parameters in your model , basically for comparison between the baseline and the proposed model. When one is performing a parametric analysis, the baseline model doesn't necessarily has to match with the actual building. Having said that, parametric analysis should be common in new constructions or sensitivity analysis of parameters(example of window glazing provided by Andy and Solar heat gain coefficient provided by Haider). Additionally, live analysis should be helpful when one is performing an energy analysis of an existing construction.
Please correct me if I am missing anything.
-Diwanshu

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