Relation ThermalZone --> UsageZone
Created by: JoachimBenner
The relation relates from ThermalZone to UsageZone has cardinality 0.., which means that one ThermalZone may be related with multiple UsageZones. Furthermore, the UML model indicates that one UsageZone may be related with more than one ThermalZone. From my point of view, both cardinalities are not useful.
1.) Thermal Zone referencing multiple UsageZones (BLDG_1 in attached example)
A basic feature of a ThermalZone is to be isotherm, which means that heat transfer can only occur via a ThermalBoundary, but not within a ThermalZone. However, if we have two UsageZones with different temperature level within one ThermalZone, there will be heat transfer within the ThermalZone. Thus, a ThermalZone cannot be geometrically separated into different UsageZones. What is the sense to partition the same volumetric part of a building into different UsageZones, how are, for instance, different heating or cooling schedules overlayed?
2.) Two ThermalZones reference the same UsageZone (BLDG_2 in attached example)
For energy simulations, the main purpose of the UsageZone concept is to provide the different ThermalZones with input data like set-point temperatures and internal gains. I can imagine that different ThermalZones can use the same heating, cooling or ventilation schedules, but the UsageZone also has a property internalGains (specifying the total internal losses or gains within this UsageZone), and relations to the building units, occupants and facilities related with the UsageZone. If the UsageZone is related with different ThermalZones, how shall the heat sources and heat sinks be distributed among the ThermalZones? There is no information available for doing this, and therefore the concept is not really useful in practice. ThermalZone-UsageZone.zip