Model Exploration

Model Exploration#

Note

The purpose of this tutorial is to explore a model by learning the following:

  1. Parsing (loading) an existing model

  2. Querying an existing model.

For this tutorial, we’ll use an existing equipment model of a variable air volume (VAV) terminal unit with cooling only from section 4.1 of ASHRAE Guideline 36-2021. This and other example models are available from Open223 Models.

Model Parsing#

First, we’ll create a new empty graph then parse (load) an existing graph into it using the Python RDFLib library.

from rdflib import Graph

# Create a Graph
g = Graph()

# Parse in an RDF file hosted on the Internet
g.parse("https://models.open223.info/guideline36-2021-A-1.ttl", format="ttl")

<Graph identifier=N99c1f883d217424d95b2935c6c0eed9b (<class 'rdflib.graph.Graph'>)>

Next, we’ll explore the model’s size by printing the number of triples in it.

# Print the number of "triples" in the Graph
print(f"Graph g has {len(g)} statements.")

Graph g has 102 statements.

Finally, we’ll print the contents of the model since it’s not that large.

# Print out the entire Graph in the RDF Turtle format
print(g.serialize(format="turtle"))

@prefix g36: <http://data.ashrae.org/standard223/1.0/extensions/g36#> .
@prefix mysystem: <http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix qudt: <http://qudt.org/schema/qudt/> .
@prefix qudtqk: <http://qudt.org/vocab/quantitykind/> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix s223: <http://data.ashrae.org/standard223#> .
@prefix unit: <http://qudt.org/vocab/unit/> .

mysystem: a owl:Ontology ;
    rdfs:label "" ;
    owl:imports <http://data.ashrae.org/standard223/1.0/model/all> .

mysystem:PhysicalSpace a s223:PhysicalSpace ;
    rdfs:label "Physicalspace" ;
    s223:encloses mysystem:PhysicalSpace-hvac-domain .

mysystem:VAVCoolingOnly a s223:SingleDuctTerminal,
        g36:VAV ;
    rdfs:label "Vavcoolingonly" ;
    s223:cnx mysystem:VAVCoolingOnly-in,
        mysystem:VAVCoolingOnly-out ;
    s223:contains mysystem:VAVCoolingOnly-damper .

mysystem:VAVCoolingOnly-damper-actuator a s223:Actuator ;
    rdfs:label "Vavcoolingonly Damper Actuator" ;
    s223:actuatedByProperty mysystem:VAVCoolingOnly-damper-command ;
    s223:actuates mysystem:VAVCoolingOnly-damper .

mysystem:VAVCoolingOnly-discharge-air-flow-sensor a s223:Sensor ;
    rdfs:label "Vavcoolingonly Discharge Air Flow Sensor" ;
    s223:hasObservationLocation mysystem:VAVCoolingOnly-out ;
    s223:observes mysystem:VAVCoolingOnly-discharge-air-flow .

mysystem:VAVCoolingOnly-duct-after-damper a s223:Connection,
        s223:Duct ;
    rdfs:label "Vavcoolingonly Duct After Damper" ;
    s223:hasMedium s223:Fluid-Air .

mysystem:VAVCoolingOnly-duct-before-damper a s223:Connection,
        s223:Duct ;
    rdfs:label "Vavcoolingonly Duct Before Damper" ;
    s223:hasMedium s223:Fluid-Air .

mysystem:zone a s223:Zone,
        g36:Zone ;
    rdfs:label "Zone" ;
    s223:hasDomain s223:Domain-HVAC ;
    s223:hasDomainSpace mysystem:PhysicalSpace-hvac-domain ;
    s223:hasProperty mysystem:zone-co2-concentration,
        mysystem:zone-temp .

mysystem:PhysicalSpace-hvac-domain-in a s223:InletConnectionPoint ;
    rdfs:label "Physicalspace Hvac Domain In" ;
    s223:cnx mysystem:vav-supply-to-room-connection ;
    s223:hasMedium s223:Fluid-Air .

mysystem:PhysicalSpace-hvac-domain-out a s223:OutletConnectionPoint ;
    rdfs:label "Physicalspace Hvac Domain Out" ;
    s223:cnx mysystem:room-return-to-vav-connection ;
    s223:hasMedium s223:Fluid-Air .

mysystem:VAVCoolingOnly-damper-in a s223:InletConnectionPoint ;
    rdfs:label "Vavcoolingonly Damper In" ;
    s223:hasMedium s223:Fluid-Air ;
    s223:mapsTo mysystem:VAVCoolingOnly-in .

mysystem:VAVCoolingOnly-damper-out a s223:OutletConnectionPoint ;
    rdfs:label "Vavcoolingonly Damper Out" ;
    s223:hasMedium s223:Fluid-Air ;
    s223:mapsTo mysystem:VAVCoolingOnly-out .

mysystem:VAVCoolingOnly-damper-position a s223:QuantifiableObservableProperty ;
    rdfs:label "Vavcoolingonly Damper Position" ;
    qudt:hasQuantityKind qudtqk:DimensionlessRatio ;
    qudt:hasUnit unit:PERCENT .

mysystem:zone-co2-concentration a s223:QuantifiableObservableProperty ;
    rdfs:label "Zone Co2 Concentration" ;
    s223:ofMedium s223:Fluid-Air ;
    s223:ofSubstance s223:Constituent-CO2 ;
    qudt:hasQuantityKind qudtqk:MoleFraction ;
    qudt:hasUnit unit:PPM .

mysystem:zone-temp a s223:QuantifiableObservableProperty ;
    rdfs:label "Zone Temp" ;
    qudt:hasQuantityKind qudtqk:Temperature ;
    qudt:hasUnit unit:DEG_C .

mysystem:PhysicalSpace-hvac-domain a s223:DomainSpace ;
    rdfs:label "Physicalspace Hvac Domain" ;
    s223:cnx mysystem:PhysicalSpace-hvac-domain-in,
        mysystem:PhysicalSpace-hvac-domain-out ;
    s223:hasDomain s223:Domain-HVAC .

mysystem:VAVCoolingOnly-damper a s223:Damper,
        g36:Damper ;
    rdfs:label "Vavcoolingonly Damper" ;
    s223:cnx mysystem:VAVCoolingOnly-damper-in,
        mysystem:VAVCoolingOnly-damper-out ;
    s223:hasProperty mysystem:VAVCoolingOnly-damper-command,
        mysystem:VAVCoolingOnly-damper-position .

mysystem:VAVCoolingOnly-damper-command a s223:QuantifiableActuatableProperty ;
    rdfs:label "Vavcoolingonly Damper Command" ;
    s223:hasAspect s223:Binary-Position ;
    qudt:hasQuantityKind qudtqk:DimensionlessRatio ;
    qudt:hasUnit unit:PERCENT .

mysystem:VAVCoolingOnly-discharge-air-flow a s223:QuantifiableObservableProperty ;
    rdfs:label "Vavcoolingonly Discharge Air Flow" ;
    s223:hasAspect s223:Role-Discharge ;
    qudt:hasQuantityKind qudtqk:VolumeFlowRate ;
    qudt:hasUnit unit:FT3-PER-MIN .

mysystem:VAVCoolingOnly-in a s223:InletConnectionPoint ;
    rdfs:label "Vavcoolingonly In" ;
    s223:cnx mysystem:room-return-to-vav-connection ;
    s223:hasMedium s223:Fluid-Air .

mysystem:room-return-to-vav-connection a s223:Connection ;
    rdfs:label "Room Return To Vav Connection" ;
    s223:hasMedium s223:Fluid-Air .

mysystem:vav-supply-to-room-connection a s223:Connection ;
    rdfs:label "Vav Supply To Room Connection" ;
    s223:hasMedium s223:Fluid-Air .

mysystem:VAVCoolingOnly-out a s223:OutletConnectionPoint ;
    rdfs:label "Vavcoolingonly Out" ;
    s223:cnx mysystem:vav-supply-to-room-connection ;
    s223:hasMedium s223:Fluid-Air ;
    s223:hasProperty mysystem:VAVCoolingOnly-discharge-air-flow .

Model Querying#

After exploring the model to get a sense for what it contains, let’s query the model using RDFLib (this can also be done with Open223 Query). For this tutorial, we’ll query the model for all the VAV terminal’s points, which are instances of the following classes:

Open223 Explore links:

# Query the data in g using SPARQL
q = """
PREFIX s223: <http://data.ashrae.org/standard223#>

SELECT ?obj WHERE {
  { ?obj a s223:QuantifiableActuatableProperty . }
  	UNION
  { ?obj a s223:QuantifiableObservableProperty . }
}
"""

# Apply the query to the graph and iterate through results
for r in g.query(q):
    print(r)

(rdflib.term.URIRef('http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#VAVCoolingOnly-damper-command'),)
(rdflib.term.URIRef('http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#VAVCoolingOnly-damper-position'),)
(rdflib.term.URIRef('http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#zone-co2-concentration'),)
(rdflib.term.URIRef('http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#zone-temp'),)
(rdflib.term.URIRef('http://data.ashrae.org/standard223/1.0/data/guideline36-2021-A-1#VAVCoolingOnly-discharge-air-flow'),)
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