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Why is energy modeling important?

asked 2014-09-01 15:32:06 -0500

Monika Sharma's avatar

updated 2016-10-20 20:00:04 -0500

As a person new to the field I want to know the importance of energy modeling. Particularly the importance of it in future.

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Quite a general question but perhaps very relevant. You can make it more specific by listing possible types of answers -- ie: studies that have been done showing importance, guidelines which give benefits, etc.

Clayton Miller's avatar Clayton Miller  ( 2014-09-18 07:14:57 -0500 )edit

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answered 2014-09-18 15:05:58 -0500

This is a riff (actually a meta-riff) on the previous answer by @PC Thomas who listed: 1) compliance and "beyond compliance" calculations and 2) design.

Simulation is important in use cases like design—which include retrofit planning, master planning, standard development, and efficiency-program development and to a lesser building operations—because it enables virtual prototyping. Buildings, especially commercial buildings, are not mass produced consumer goods. They are custom one-off's that are sensitive to both intrinsic requirements and extrinsic context. Mass produced goods are physically prototyped and tested dozens or even hundreds of times before the final prototype is replicated. That approach is not practical for individual buildings. And whereas energy conservation measures and their performance characteristics do transfer from one building to another, this transfer is often sensitive to building requirements and context as well as to the presence of other design elements and is thus is best viewed as qualitative. Simulation helps address this shortcoming by quantifying the impact of measures in a new context.

Similarly, simulation is important in uses cases like (performance path) code compliance—which include green building certification, asset rating and labeling, and others—because it provides a way to isolate the "intrinsic" performance of a building from its occupancy, operations, and prevailing conditions. Such attribution is useful and yet not useful enough to justify evicting a building's occupants and placing the building within a climate controlled shell for the purpose of performing controlled experiments.

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answered 2014-09-11 01:58:32 -0500

PC Thomas's avatar

whole building energy simulation can be used for:

  1. Carrying out compliance studies, for example, to ensure compliance with minimum energy efficiency standards like ASHRAE 90.1 in the USA, NCC Section-J in Australia or the ECBC in India. In these instances, the analyst is comparing the performance of a "reference" building against a "proposed" design solution. This compliance energy modeling scenario may be extended to voluntary codes like LEED and GreenStar. In all these instances, the energy modeler is trying to generate results which meet or exceed certain criteria, when many of the input parameters are pre-defined or constrained (for example, geometry supplied by the architecture firm, operation schedules, minimum EERs, maximum lighting power density, etc for the reference case are prescribed by relevant codes and standards)

  2. It is also possible (and much more fun) to use energy simulation as a early design tool. To do this effectively requires experience in all of the building systems that impact energy consumption. It can take up a lot of time, a lot of what-if scenarios, and all our new employees go through what we refer to as a "simulation addiction" phase. In our office we also talk about "building architecture" model studies and "systems architecture" model studies. Our experience is that there is a lot of expertise on building architecture in the industry, which may be described (with some simplification) as optimising the energy performance of the building envelope. "Systems architecture" requires significant experience and knowledge of the design philosophies of the various types of environmental control systems and their practical limitations, whether these are traditional fully air-conditioned buildings, or mixed mode hybrid solutions. We could do better in this area, and the test is to compare predicted performance against a 12 month period of "normal" occupancy and operation. A quick tip: we have found that in high performance, fully air-conditioned buildings, one may only be able to represent about 50% of the building's total energy consumption in the energy simulation model. The remainder may just as well be estimated using spreadsheet calculations.

Good luck, and have fun!

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Asked: 2014-09-01 15:32:06 -0500

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Last updated: Oct 18 '16