Merge branch 'dev'

docs/whats_new.rst

@@ -3,6 +3,7 @@ What's New
 
 Discover notable new features and improvements in each release
 
+.. include::  whats_new/v0-7-6-001.rst
 .. include::  whats_new/v0-7-6.rst
 .. include::  whats_new/v0-7-5.rst
 .. include::  whats_new/v0-7-4.rst

docs/whats_new/v0-7-6-001.rst

@@ -0,0 +1,17 @@
+v0.7.6.post1 - Newton's Nature (August, 02, 2024)
++++++++++++++++++++++++++++++++++++++++++++++++++
+
+This is a post release for version 0.7.6 to fix a bug in the postprocessing of
+the :code:`HeatExchanger` classes.
+
+Bug Fixes
+#########
+- An exception is catched in the heat exchanger post processing, in case the
+  heat exchanger effectiveness cannot be calculated when hot side or cold side
+  inlet temperature value are out of bounds of the fluid properties for the
+  other side respectively
+  (`PR #533 <https://github.com/oemof/tespy/pull/533>`__).
+
+Contributors
+############
+- Francesco Witte (`@fwitte <https://github.com/fwitte>`__)

pyproject.toml

@@ -24,7 +24,7 @@ exclude = ["docs/_build"]
 
 [project]
 name = "tespy"
-version = "0.7.6"
+version = "0.7.6.post1"
 description = "Thermal Engineering Systems in Python (TESPy)"
 readme = "README.rst"
 authors = [

src/tespy/__init__.py

@@ -3,7 +3,7 @@
 import os
 
 __datapath__ = os.path.join(importlib.resources.files("tespy"), "data")
-__version__ = '0.7.6 - Newton\'s Nature'
+__version__ = '0.7.6.post1 - Newton\'s Nature'
 
 # tespy data and connections import
 from . import connections  # noqa: F401

src/tespy/components/heat_exchangers/base.py

@@ -16,6 +16,7 @@
 
 from tespy.components.component import Component
 from tespy.components.component import component_registry
+from tespy.tools import logger
 from tespy.tools.data_containers import ComponentCharacteristics as dc_cc
 from tespy.tools.data_containers import ComponentProperties as dc_cp
 from tespy.tools.data_containers import GroupedComponentCharacteristics as dc_gcc
@@ -1057,15 +1058,32 @@ def calc_parameters(self):
         self.kA.val = -self.Q.val / self.td_log.val
 
         # heat exchanger efficiencies
-        self.eff_hot.val = (
-            (self.outl[0].h.val_SI - self.inl[0].h.val_SI)
-            / self.calc_dh_max_hot()
-        )
-
-        self.eff_cold.val = (
-            (self.outl[1].h.val_SI - self.inl[1].h.val_SI)
-            / self.calc_dh_max_cold()
-        )
+        try:
+            self.eff_hot.val = (
+                (self.outl[0].h.val_SI - self.inl[0].h.val_SI)
+                / self.calc_dh_max_hot()
+            )
+        except ValueError:
+            self.eff_hot.val = np.nan
+            msg = (
+                "Cannot calculate heat exchanger hot side effectiveness "
+                "because cold side inlet temperature is out of bounds for hot "
+                "side fluid."
+            )
+            logger.warning(msg)
+        try:
+            self.eff_cold.val = (
+                (self.outl[1].h.val_SI - self.inl[1].h.val_SI)
+                / self.calc_dh_max_cold()
+            )
+        except ValueError:
+            self.eff_cold.val = np.nan
+            msg = (
+                "Cannot calculate heat exchanger cold side effectiveness "
+                "because hot side inlet temperature is out of bounds for cold "
+                "side fluid."
+            )
+            logger.warning(msg)
         self.eff_max.val = max(self.eff_hot.val, self.eff_cold.val)
 
     def entropy_balance(self):

tests/test_components/test_heat_exchangers.py

@@ -476,6 +476,37 @@ def test_HeatExchanger(self, tmp_path):
         )
         assert round(self.c3.m.val, 2) == 7.96
 
+    def test_HeatExchanger_effectiveness_invalid(self):
+
+        instance = HeatExchanger('heat exchanger')
+        self.setup_HeatExchanger_network(instance)
+
+        # remove fluid specifications
+        self.c1.set_attr(fluid={f: None for f in self.c1.fluid.val})
+        self.c3.set_attr(fluid={f: None for f in self.c3.fluid.val})
+
+        # add new fluids
+        # temperature range > 300 °C
+        self.c1.set_attr(fluid={"INCOMP::NaK": 1}, m=10, T=400, p=1)
+        self.c2.set_attr(T=350, p=1)
+        # temperature range < 100 °C at 1 bar
+        self.c3.set_attr(fluid={"INCOMP::Water": 1}, T=25, p=1)
+        self.c4.set_attr(T=50, p=1)
+        instance.set_attr(eff_cold=None, eff_hot=None, pr1=None, pr2=None)
+
+        self.nw.solve("design")
+        self.nw._convergence_check()
+        msg = (
+            'Value of cold effectiveness must be nan but is '
+            f'{round(instance.eff_cold.val, 1)}.'
+        )
+        assert np.isnan(instance.eff_cold.val), msg
+        msg = (
+            'Value of hot effectiveness must be nan but is '
+            f'{round(instance.eff_hot.val, 1)}.'
+        )
+        assert np.isnan(instance.eff_hot.val), msg
+
     def test_Condenser(self, tmp_path):
         """Test component properties of Condenser."""
         instance = Condenser('condenser')