Clarify the absence of ventilation losses in Q_design

open-ideas · Nov 29, 2024 · 6908181 · 6908181
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diff --git a/IDEAS/Buildings/Components/Interfaces/PartialZone.mo b/IDEAS/Buildings/Components/Interfaces/PartialZone.mo
@@ -43,7 +43,7 @@ model PartialZone "Building zone model"
   final parameter Modelica.Units.SI.Power QRH_design=A*fRH
     "Additional power required to compensate for the effects of intermittent heating";
   final parameter Modelica.Units.SI.Power Q_design(fixed=false)
-    "Total design heat losses for the zone";
+    "Total design heat losses for the zone (including transmission, infiltration, and reheating; excluding ventilation)";
   parameter Medium.Temperature T_start=Medium.T_default
     "Start value of temperature"
     annotation(Dialog(tab = "Initialization"));
@@ -306,7 +306,9 @@ end Setq50;
 initial equation
   n50_int = if use_custom_n50 and not setq50.allSurfacesCustom then n50 else sum(propsBusInt.v50)/V;
 
-  Q_design=QInf_design+QRH_design+QTra_design; //Total design load for zone (additional ventilation losses are calculated in the ventilation system)
+  Q_design=QInf_design+QRH_design+QTra_design;
+  //Total design load for zone (excluding ventilation losses, these are assumed to be calculated in the ventilation system
+  //and should be added afterwards to obtain the total design heat load). See for example IDEAS.Templates.Interfaces.Building.
 
 equation
   if interzonalAirFlow.verifyBothPortsConnected then

diff --git a/IDEAS/Buildings/Components/Zone.mo b/IDEAS/Buildings/Components/Zone.mo
@@ -117,6 +117,13 @@ The model <code>ligCtr</code> determines how the lighting is controlled.
 See <a href=\"modelica://IDEAS.Buildings.Components.LightingControl\">
 IDEAS.Buildings.Components.LightingControl</a> for the available options.
 </p>
+<p>
+The design heat losses <code>Q_design</code> are calculated via an initial equation based on, but not exactly according to, NBN EN 12831-1 ANB:2020.
+This value includes heat losses via transmission (<code>QTra_design</code>) and infiltration (<code>QInf_design</code>) and accounts for reheating (<code>QRH_design</code>).
+Ventilation losses are not considered as this system is typically modelled in a seperate block, 
+see for example <a href=\"modelica://IDEAS.Templates.Interfaces.Building\"> IDEAS.Templates.Interfaces.Building</a>.
+In this model, the total design losses are calculated as the sum of the design losses from the building envelope (transmission, infiltration, reheating) and the ventilation system.
+</p>
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