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Best practice for modelling uncertainty in usage patterns?

asked 2016-07-20 05:54:27 -0500

Papachaf's avatar

updated 2018-04-14 07:33:13 -0500

I am trying to capture uncertainty due to user behaviour with my model and wondered if anyone had any suggestions for best practice on how to do this?

I am carrying out multiple runs to explore the effects of uncertainty around usage patterns (occupancy, lighting, equipment and heating cooling set point schedules). This is part of a global sensitivity analysis and the more variables I have the more runs I will need.

The two approaches I have considered are:

  • Define a range of different schedules for each category and randomly select a schedule in each category for each model run. This would allow me to have relatively complex schedules but the consideration of uncertainty is limited to the range captured in the schedules I have defined. This would only require one variable per schedule type.
  • Include a range of variables in each schedule to simulate changes in state. If the schedule is simple (eg. occupancy is zero until a start time, then 1 until an end time) then this is relatively straightforward and only needs 2 variables but the number of variables increases if the schedules is more complicated (eg. off for an hour at lunch-time).

At the moment, I think my preferred approach is the 2nd one, with a simplified schedule, so just a variable for the on time and a variable for the off time (ie. 2 variables per schedule). However, I haven't been able to find any precedents in the literature to suggest an approach. Does anyone have any suggestions for a better approach?

Thank you!

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answered 2016-07-20 07:18:23 -0500

updated 2016-07-20 10:26:41 -0500

Take a look at occupancy simulator from LBNL and Tsinghua university. It uses a compact probabilistic description of occupant movement to generate sample schedules. There is a paper about the approach in the upcoming ACEEE buildings conference.

Update: in general, you may want to look at IEA Annex 66 which deals with characterization and modeling of occupants and occupant behavior. There are about 40 participating research groups from about 15 countries, including both the LBNL and Carleton groups.

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Thank you - that's very helpful, great to be pointed in the direction of so much good literature, lots for me to think about...

Papachaf's avatar Papachaf  ( 2016-07-21 01:13:49 -0500 )edit
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answered 2016-07-20 10:18:16 -0500

In addition to the answers from Andrew and Amir, OpenStudio Server has several algorithms that can be used to deal with uncertainty if you want to use the OS analysis tools. Specifically the Morris method and Latin Hypercube Sampling.

OS analysis spreadsheet

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thank you - I'm using sobol indices (implemented in Matlab) for the Sensitivity Analysis which will give better coverage of the input space than Morris method does but I have used morris method previously. Just been to an excellent summer school on sensitivity analysis techniques which I would highly recommend if anyone is interested in future, the course materials are on the web-site - https://ec.europa.eu/jrc/en/event/tra...

Papachaf's avatar Papachaf  ( 2016-07-21 01:12:22 -0500 )edit

well, "better coverage" depends on how you parameterize the algorithms. In any case, I also wrapped the various sobol methods as well. They are not production ready but if you have interest to use them I'll make it available sooner rather than later.

BrianLBall's avatar BrianLBall  ( 2016-07-21 08:47:11 -0500 )edit
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answered 2016-07-20 09:50:13 -0500

Also take a look at the work being done at Carleton University. They have several publications on this topic and have implemented them in simulation via OpenStudio and EnergyPlus.

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Thank you that's very helpful

Papachaf's avatar Papachaf  ( 2016-07-21 01:12:48 -0500 )edit

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Asked: 2016-07-20 05:54:27 -0500

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Last updated: Jul 20 '16