Tuesday, March 22, 2011

When Models Collide

..is not a book by Wylie and Balmer, made into a movie in 1951 with a remake underway, though I am sure that's a lot more exciting than the conundrums (conundra? the word is not definitively Latin) facing the ASHRAE/SPC 201 ("Facility Smart Grid Information Model") committee this week.

Our four Rapid Development Teams (Load, Energy Manager, Meter and Generator) are meeting to compare and align the models we've been developing for these four areas, the underpinnings of the entire "Facility" (residential, industrial and commercial buildings) model that represents the end consumer of the electricity generated and conveyed by the electric grid. These models are necessary for working out the details of the data communications that will alter the ways in which energy is generated and consumed, for greater energy efficiency and make best use of existing infrastructure.

This is not an easy task. For example, the image here is a (UML) diagram of a draft of the Energy Manager model -- as one can see this is no simple model. And drawing the lines between models is not easy either; if one were to look close up one would find elements of the Load model (electric loads -- those that must remain on 24/7 and those that can be reduced or turned off if need be) engrained in it.

On top of that, these models being developed were built on initial use cases, models and data elements drafted by the Energy Information Standards Alliance (aka EIS Alliance) over the last year and a half. This was to provide a structure that would allow various models developed independently to be more readily harmonized.

But even that wasn't perfect, as this diagram seems to show (but to be fair, an extra couple of "load classes" were accidentally slipped into an energy manager model, though this wasn't revealed until a detailed analysis was performed of the alignment between two models regarding loads.

We have our work cut out for us.

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