Merge pull request #407 from lbl-srg/issue388_state

Issue388 state
lbl-srg · Apr 1, 2015 · 2968e4c · 2968e4c
2 parents 2e4ef6a + 4b444d7
commit 2968e4c
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Showing 3 changed files with 25 additions and 16 deletions.
diff --git a/Buildings/Fluid/Interfaces/PartialTwoPortTransport.mo b/Buildings/Fluid/Interfaces/PartialTwoPortTransport.mo
@@ -55,19 +55,19 @@ partial model PartialTwoPortTransport
                   m_flow_small) if show_T
     "Temperature close to port_b, if show_T = true";
 protected
-  Medium.ThermodynamicState state_a "state for medium inflowing through port_a";
-  Medium.ThermodynamicState state_b "state for medium inflowing through port_b";
-equation
-  // medium states
-  state_a = Medium.setState_phX(
+  Medium.ThermodynamicState state_a = Medium.setState_phX(
               port_a.p,
               inStream(port_a.h_outflow),
-              inStream(port_a.Xi_outflow));
-  state_b = Medium.setState_phX(
+              inStream(port_a.Xi_outflow)) if
+                 show_T or show_V_flow
+    "State for medium inflowing through port_a";
+  Medium.ThermodynamicState state_b = Medium.setState_phX(
               port_b.p,
               inStream(port_b.h_outflow),
-              inStream(port_b.Xi_outflow));
-
+              inStream(port_b.Xi_outflow)) if
+                 show_T or show_V_flow
+    "State for medium inflowing through port_b";
+equation
   // Pressure drop in design flow direction
   dp = port_a.p - port_b.p;
 
@@ -120,6 +120,13 @@ users have not used this global definition to assign parameters.
 </html>", revisions="<html>
 <ul>
 <li>
+April 1, 2015, by Michael Wetter:<br/>
+Made computation of <code>state_a</code> and <code>state_p</code>
+conditional on <code>show_T</code> or <code>show_V_flow</code>.
+This avoids computating temperature from enthalpy if temperature is
+a state of the medium, and the result is not used.
+</li>
+<li>
 October 21, 2014, by Michael Wetter:<br/>
 Revised implementation.
 </li>

diff --git a/Buildings/Fluid/Interfaces/PrescribedOutletState.mo b/Buildings/Fluid/Interfaces/PrescribedOutletState.mo
@@ -33,6 +33,9 @@ protected
     cp_default*m_flow_small*0.01
     "Small value for deltah used for regularization";
 
+  final parameter Boolean dynamic = tau > 1E-10 or tau < -1E-10
+    "Flag, true if the sensor is a dynamic sensor";
+
   Modelica.SIunits.MassFlowRate m_flow_pos
     "Mass flow rate, or zero if reverse flow";
 
@@ -50,8 +53,7 @@ protected
 
   Real k(start=1)
     "Gain to take flow rate into account for sensor time constant";
-  final parameter Boolean dynamic = tau > 1E-10 or tau < -1E-10
-    "Flag, true if the sensor is a dynamic sensor";
+
   Real mNor_flow "Normalized mass flow rate";
 
 initial equation