Heat buffer efficiency

CHANGELOG.md

@@ -1,7 +1,7 @@
-# [Unreleased-main] - 2026-02-05
+# [Unreleased-main] - 2026-02-09
 
 ## Added
-- xxx
+- heat_transfer_coeff variable of HeatStorage is read from dischargeEfficiency attribute in esdl
 
 ## Changed
 - xxx

src/mesido/esdl/esdl_heat_model.py

@@ -428,12 +428,23 @@ def convert_heat_buffer(self, asset: Asset) -> Tuple[Type[HeatBuffer], MODIFIERS
             else 10.0e6
         )
 
+        # Todo: Currently esdl does not have "heatTransferCoefficient" attribute for
+        #  heat_buffer asset. Temporarily we are using "dischargeEfficiency" attribute
+        #  of HeatStorage asset attribute in ESDL to define heat_transfer_coeff.
+        #  Once, "heatTransferCoefficient" attribute is added into esdl,
+        #  we can update this part.
+        heat_transfer_coeff = (
+            asset.attributes.get("heatTransferCoefficient")
+            or asset.attributes.get("dischargeEfficiency")
+            or 1.0
+        )
+
         q_nominal = self._get_connected_q_nominal(asset)
 
         modifiers = dict(
             height=r,
             radius=r,
-            heat_transfer_coeff=1.0,
+            heat_transfer_coeff=heat_transfer_coeff,
             min_fraction_tank_volume=min_fraction_tank_volume,
             Stored_heat=dict(min=min_heat, max=max_heat),
             Heat_buffer=dict(min=-hfr_discharge_max, max=hfr_charge_max),

src/mesido/pycml/component_library/milp/heat/heat_buffer.py

@@ -32,7 +32,7 @@ def __init__(self, name, **modifiers):
 
         self.component_type = "heat_buffer"
 
-        self.heat_transfer_coeff = 1.0
+        self.heat_transfer_coeff = nan
         self.height = 5.0
         self.radius = 10.0
         self.volume = math.pi * self.radius**2 * self.height

tests/models/test_case_small_network_with_ates_buffer_geo/model/test_case_small_network_with_ates_buffer_geo.esdl

@@ -401,7 +401,7 @@
           </investmentCosts>
         </costInformation>
       </asset>
-      <asset xsi:type="esdl:HeatStorage" name="HeatStorage_74c1" id="74c13eed-9ca8-4247-bd72-a68e242d8e1b" maxDischargeRate="10000000.0" maxChargeRate="10000000.0" volume="500.0">
+      <asset xsi:type="esdl:HeatStorage" name="HeatStorage_74c1" id="74c13eed-9ca8-4247-bd72-a68e242d8e1b" maxDischargeRate="10000000.0" maxChargeRate="10000000.0" volume="500.0" dischargeEfficiency="0.85">
         <geometry xsi:type="esdl:Point" lon="4.313871860504151" CRS="WGS84" lat="52.042658996032856"/>
         <port xsi:type="esdl:InPort" id="8c09b9ff-5070-4fbc-97fe-db7a501932dc" name="In" connectedTo="636a1943-2289-4d57-a2dd-33aaa4f25b49" carrier="7b32e287-d775-480c-b317-64ffdacf12c9"/>
         <port xsi:type="esdl:OutPort" id="cc725203-e648-490f-a12d-91fa85ee58f2" name="Out" connectedTo="a581c340-3cab-46b1-924f-c5ddc0120de6" carrier="7b32e287-d775-480c-b317-64ffdacf12c9_ret"/>

tests/test_max_size_and_optional_assets.py

@@ -30,6 +30,7 @@ def test_max_size_and_aggr_count(self):
         assets should not be placed by the optmizer because of heat losses.
 
         Checks:
+        - Check that heat_transfer_coeff can be read from esdl
         - Check that source 1 is utilized and also placed
         - Check that source 2 is utilized and placed
         - Check that the geothermal source is not placed
@@ -60,6 +61,20 @@ def test_max_size_and_aggr_count(self):
         results = solution.extract_results()
         parameters = solution.parameters(0)
 
+        # Test that heat_transfer_coeff can be read from esdl
+        esdl_asset = solution.esdl_assets[solution.esdl_asset_name_to_id_map["HeatStorage_74c1"]]
+        try:
+            heat_transfer_coeff = esdl_asset.attributes["heatTransferCoefficient"]
+        except KeyError:
+            # Currently, "heatTransferCoefficient" attribute is not available in esdl.
+            # We are temporariliy using "dischargeEfficiency" attribute in esdl
+            # to define heat_transfer_coeff
+            heat_transfer_coeff = esdl_asset.attributes["dischargeEfficiency"]
+
+        np.testing.assert_allclose(
+            parameters["HeatStorage_74c1.heat_transfer_coeff"], heat_transfer_coeff
+        )
+
         # Producer 1 and geothermal source should not produce due to higher cost
         # Producer 2 should produce
         heat_1 = results["HeatProducer_1.Heat_source"]