SimModel

The Simulation Domain Model, or SimModel, is a new XML-based schema that supports Simergy. SimModel is largely a union of the IFC data schema (BuildingSMART, 2012) and the EnergyPlus input data model. It was created in order to support interoperability between various building energy simulation tools, and to enable future versions of Simergy to support other simulation programs, including Radiance (DOE, 2011)(Radiance, 2011) and Modelica-based tools (Modelica, 2012).

SimModel includes a class definition for Systems. Class ‘SimSystem’ includes THE ‘Type’ definitions ‘HVACAir’, ‘HVACHotWater’, ‘HVACChilledWater’, ‘HVACMixedWater’ AND ‘HVACCondenser’ to define each of the mechanical fluid loops in EnergyPlus. Each ‘Type’ includes further definitions for various associated ‘Sub-Types’. For example, the SimSystem type HVACAir has associated Sub-Types that include ‘Supply’ and ‘Demand’. Each Sub-Type is identified as a sub-system that is part of the system ‘HVACAir’. The type ‘HVACAir’ also contains other related sub-types that further classify ‘Supply’ as ‘SupplySideSupplyPath’, ‘SupplySideReturnPath’, and ‘Outside Air’ AND further classify ‘Demand’ as ‘DemanSideSupplyPath’, ‘DemandSideZoneHVAC’ And ‘DemandSideReturn-Path’.

The System/Type/Sub-Type categorization ensures that each component in the air loop can be assigned to either a Supply or Demand sub-system and then further assigned to appropriate sub-systems, such as SupplySideSupplyPath or SupplySideReturnPath, based on the framework and validation rules within Simergy.

The decomposition of HVAC loops into Supply and Demand subloops, and the further decomposition into Branches and Zone Air Paths, is fundamental in EnergyPlus but this decomposition is not required for inherently modular tools such as TRNSYS and Modelica-based tools.

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