Revise heat pump and add COP importer

pyproject.toml

@@ -48,6 +48,7 @@ examples = []
 importer = ["pyproj"]
 test = [
   "pytest",
+  "tespy",
   "coverage",
   "pvlib",
   "demandlib",

src/oemof/eesyplan/components/converters/HeatPump.py

@@ -9,13 +9,12 @@ class HeatPump(Converter):
     def __init__(
         self,
         name,
-        bus_in_heat,
+        project_data,
+        installed_capacity,
         bus_in_electricity,
         bus_out_heat,
-        project_data,
+        bus_in_heat=None,
         age_installed=0,
-        installed_capacity=0,
-        capex_fix=1000,
         capex_var=1000,
         opex_var=0.01,
         opex_fix=10,
@@ -50,9 +49,6 @@ def __init__(
             Number of years the asset has already been in operation.
         installed_capacity : float, default=0
             Already existing installed capacity.
-        capex_fix : float, default=1000
-            Specific investment costs of the asset related to the
-            installed capacity (CAPEX).
         capex_var : float, default=1000
             Specific investment costs of the asset related to the
             installed capacity (CAPEX).
@@ -77,14 +73,13 @@ def __init__(
         Examples
         --------
         >>> from oemof.eesyplan import Project
-        >>> from oemof.solph import Bus
-        >>> el_bus = Bus(label="electricity_bus")
-        >>> ambient_heat_bus = Bus(label="ambient_heat_bus")
-        >>> heat_bus = Bus(label="heat_bus")
+        >>> from oemof.eesyplan import CarrierBus
+        >>> el_bus = CarrierBus(name="electricity_bus")
+        >>> ambient_heat_bus = CarrierBus(name="ambient_heat_bus")
+        >>> heat_bus = CarrierBus(name="heat_bus")
         >>> my_heat_pump = HeatPump(
         ...     name="air_source_heat_pump",
         ...     bus_in_electricity=el_bus,
-        ...     bus_in_heat=ambient_heat_bus,
         ...     bus_out_heat=heat_bus,
         ...     installed_capacity=15,
         ...     cop=3.5,
@@ -122,7 +117,7 @@ def __init__(
             project_data=project_data,
         )
 
-        inputs = {bus_in_heat: Flow(), bus_in_electricity: Flow()}
+        inputs = {bus_in_electricity: Flow()}
 
         outputs = {
             bus_out_heat: Flow(
@@ -133,9 +128,12 @@ def __init__(
 
         conversion_factors = {
             bus_in_electricity: 1 / cop,
-            bus_in_heat: (cop - 1) / cop,
         }
 
+        if bus_in_heat is not None:
+            conversion_factors[bus_in_heat] = (cop - 1) / cop
+            inputs[bus_in_heat] = Flow()
+
         super().__init__(
             label=name,
             outputs=outputs,
@@ -146,7 +144,6 @@ def __init__(
         self.name = name
         self.age_installed = age_installed
         self.installed_capacity = installed_capacity
-        self.capex_fix = capex_fix
         self.capex_var = capex_var
         self.opex_var = opex_var
         self.opex_fix = opex_fix

src/oemof/eesyplan/importer/cop.py

@@ -0,0 +1,155 @@
+import numpy as np
+
+try:
+    from tespy.components import Compressor
+    from tespy.components import CycleCloser
+    from tespy.components import SimpleHeatExchanger
+    from tespy.components import Valve
+    from tespy.connections import Connection
+    from tespy.networks import Network
+except (ImportError, ModuleNotFoundError):
+    Network = None
+
+
+def calculate_cop_simple(
+    temperature_source, temperature_supply, quality_factor
+):
+    """
+
+    Parameters
+    ----------
+    temperature_source : float or array-like
+    temperature_supply : float or array-like
+    quality_factor : float or array-like
+
+    Returns
+    -------
+    float or array-like
+
+    Examples
+    --------
+    >>> round(calculate_cop_simple(10.0, 55.0, 0.5), 2)
+    3.65
+
+    """
+    temperature_source = np.array(temperature_source)
+    temperature_supply = np.array(temperature_supply)
+    quality_factor = np.array(quality_factor)
+
+    cop = (
+        (temperature_supply + 273.15)
+        * quality_factor
+        / (temperature_supply - temperature_source)
+    )
+    if isinstance(cop, np.float64):
+        return cop.item()
+
+    return cop
+
+
+def calculate_cop_tespy(
+    temperature_source,
+    temperature_supply,
+    refrigerant="R290",
+    capacity=1000,
+    pressure_loss_factor_hex=1,
+    eta_s=0.55,
+):
+    """
+    Temperature input must have the same length.
+
+    Parameters
+    ----------
+    temperature_source
+    temperature_supply
+    capacity
+    refrigerant
+    pressure_loss_factor_hex
+    eta_s
+
+    Returns
+    -------
+
+    Examples
+    --------
+    >>> c = calculate_cop_simple(10.0, [35, 45, 55], 0.5)
+    >>> [round(float(val), 2) for val in c]
+    [6.16, 4.54, 3.65]
+    >>> c = calculate_cop_tespy([10.0] * 3, [35, 45, 55])
+    >>> [round(float(val), 2) for val in c]
+    [6.33, 4.54, 3.52]
+    >>> c = calculate_cop_tespy([10.0] * 3, [35, 45, 55], refrigerant="R134a")
+    >>> [round(float(val), 2) for val in c]
+    [6.42, 4.62, 3.59]
+    >>> round(calculate_cop_simple(10, 40, 0.5), 2)
+    5.22
+    >>> round(calculate_cop_tespy(10, 40), 2)
+    5.29
+    """
+
+    if Network is None:
+        msg = (
+            "TESPy is required to use this function.\n"
+            "Please install the tespy package: 'pip install tespy'"
+        )
+        raise ModuleNotFoundError(msg)
+
+    if isinstance(temperature_source, (float | int)):
+        temperature_source = [temperature_source]
+        temperature_supply = [temperature_supply]
+        length = 1
+    else:
+        length = len(temperature_source)
+
+    temperature_source = np.array(temperature_source)
+    temperature_supply = np.array(temperature_supply)
+
+    # create a network object with R134a as fluid
+    my_plant = Network()
+
+    # set the unitsystem for temperatures to °C and for pressure to bar
+    my_plant.units.set_defaults(
+        temperature="degC",
+        pressure="bar",
+        pressure_difference="bar",
+        enthalpy="kJ/kg",
+        heat="kW",
+        power="kW",
+    )
+
+    cc = CycleCloser("cycle closer")
+
+    # heat sink
+    co = SimpleHeatExchanger("condenser")
+    # heat source
+    ev = SimpleHeatExchanger("evaporator")
+
+    va = Valve("expansion valve")
+    cp = Compressor("compressor")
+
+    # connections of heat pump
+    c1 = Connection(cc, "out1", ev, "in1", label="1")
+    c2 = Connection(ev, "out1", cp, "in1", label="2")
+    c3 = Connection(cp, "out1", co, "in1", label="3")
+    c4 = Connection(co, "out1", va, "in1", label="4")
+    c0 = Connection(va, "out1", cc, "in1", label="0")
+
+    # this line is crutial: you have to add all connections to your network
+    my_plant.add_conns(c1, c2, c3, c4, c0)
+
+    co.set_attr(pr=pressure_loss_factor_hex, Q=capacity * -1)
+    ev.set_attr(pr=pressure_loss_factor_hex)
+    cp.set_attr(eta_s=eta_s)
+
+    def get_cop(c_src, c_sup, n):
+        c_src.set_attr(T=temperature_source[n], x=1, fluid={refrigerant: 1})
+        c_sup.set_attr(T=temperature_supply[n], x=0)
+
+        my_plant.solve("design", print_results=False)
+        return abs(co.Q.val) / cp.P.val
+
+    cops = [get_cop(c2, c4, n) for n in range(length)]
+
+    if len(cops) == 1:
+        cops = float(cops[0])
+    return cops

tests/test_constraints/test_heat_pump.py

@@ -70,13 +70,13 @@ def test_heat_pump_investment():
     es.add(el_bus, ambient_bus, heat_bus)
     heat_pump = HeatPump(
         name="air_source_heat_pump",
+        installed_capacity=0,
         bus_in_electricity=el_bus,
         bus_in_heat=ambient_bus,
         bus_out_heat=heat_bus,
         maximum_capacity=15,
         optimize_cap=True,
         capex_var=100,
-        capex_fix=10,
         opex_var=-10,
         opex_fix=1,
         cop=[3.5, 3.2] * 5,

tests/test_importer.py

@@ -0,0 +1,31 @@
+import importlib
+import sys
+from unittest.mock import patch
+
+import pytest
+
+from oemof.eesyplan.importer import cop
+
+
+def test_tespy_not_installed():
+    """Set Network to None."""
+    with patch.object(cop, "Network", None):
+        with pytest.raises(ModuleNotFoundError, match="TESPy is required"):
+            cop.calculate_cop_tespy(10, 40)
+
+
+def test_tespy_not_installed_via_import():
+    """As if tespy would not exist."""
+    with patch.dict(
+        sys.modules,
+        {
+            "tespy": None,
+            "tespy.components": None,
+            "tespy.connections": None,
+            "tespy.networks": None,
+        },
+    ):
+        importlib.reload(cop)
+
+        with pytest.raises(ModuleNotFoundError, match="TESPy is required"):
+            cop.calculate_cop_tespy(10, 40)