Fix issue 332

Author: wouterpeere

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Added support for DHW profiles in optimisation (issue #272).
 - Added Prandtl number to FluidData class (issue #326).
+- Pressure drop calculation for horizontal pipe and total system (issue #332).
 
 ## Changed
 

GHEtool/Methods/pressure_drop_calculation.py

@@ -0,0 +1,116 @@
+import copy
+
+import numpy as np
+import pygfunction as gt
+
+from GHEtool import *
+from GHEtool.VariableClasses.PipeData import _PipeData
+from math import pi
+
+
+def calculate_pressure_drop_horizontal(fluid_data: FluidData, r_in: float, length: float, minor_losses: float) -> float:
+    """
+    This function calculates the pressure drop in the horizontal pipe.
+
+    Parameters
+    ----------
+    fluid_data : FluidData
+        Fluid data
+    r_in : float
+        Inner pipe diameter [m]
+    length : float
+        Length of the pipe [m]
+    minor_losses : float
+        Coefficient for minor losses [-]
+
+    Returns
+    -------
+    Pressure drop : float
+        Pressure drop [kPa]
+    """
+    # Darcy fluid factor
+    fd = gt.pipes.fluid_friction_factor_circular_pipe(
+        fluid_data.mfr,
+        r_in,
+        fluid_data.mu,
+        fluid_data.rho,
+        1e-6)
+    A = pi * r_in ** 2
+    V = (fluid_data.vfr / 1000) / A
+
+    return ((fd * length / (2 * r_in) + minor_losses) * fluid_data.rho * V ** 2 / 2) / 1000
+
+
+def calculate_total_pressure_drop(pipe_data: _PipeData, fluid_data: FluidData, borehole_length: float,
+                                  r_in: float, distance: float, minor_losses: float) -> float:
+    """
+    This function calculates the total pressure drop of your system, assuming every borehole is brought individually
+    to the main collector.
+
+    Parameters
+    ----------
+    pipe_data : PipeData
+        Pipe data
+    fluid_data : FluidData
+        Fluid data
+    borehole_length : float
+        Borehole length [m]
+    r_in : float
+        Inner pipe diameter [m]
+    distance : float
+        distance from the borehole to the collector [m]
+    minor_losses : float
+        Coefficient for minor losses [-]
+
+    Returns
+    -------
+    Pressure drop : float
+        Pressure drop [kPa]
+    """
+
+    return pipe_data.pressure_drop(fluid_data, borehole_length) + \
+        calculate_pressure_drop_horizontal(fluid_data, r_in, distance * 2, minor_losses)
+
+
+def create_pressure_drop_curve(pipe_data: _PipeData, fluid_data: FluidData, borehole_length: float,
+                               r_in: float, distance: float, minor_losses: float, range: float = 2,
+                               datapoints: int = 30) -> tuple:
+    """
+    This function calculates the pressure drop for different flow rates.
+
+    Parameters
+    ----------
+    pipe_data : PipeData
+        Pipe data
+    fluid_data : FluidData
+        Fluid data
+    borehole_length : float
+        Borehole length [m]
+    r_in : float
+        Inner pipe diameter [m]
+    distance : float
+        distance from the borehole to the collector [m]
+    minor_losses : float
+        Coefficient for minor losses [-]
+    range : float
+        Multiplier of the flow rate for the range of the data.
+    datapoints : int
+        Number of datapoints.
+
+    Returns
+    -------
+    pressure drop, flow rates : np.ndarray, np.ndarray
+        Array with the pressure drops [kPa], Array with the flow rates per borehole [l/s]
+    """
+
+    flow_rates = np.linspace(0, range * fluid_data.vfr, datapoints)
+    pressure_drops = np.zeros(flow_rates.shape)
+
+    new_fluid = copy.copy(fluid_data)
+
+    for i, val in enumerate(flow_rates):
+        new_fluid.vfr = val
+        pressure_drops[i] = calculate_total_pressure_drop(pipe_data, new_fluid, borehole_length, r_in, distance,
+                                                          minor_losses)
+
+    return np.nan_to_num(pressure_drops), flow_rates

GHEtool/VariableClasses/PipeData/MultipleUTube.py

@@ -3,8 +3,8 @@
 import numpy as np
 import pygfunction as gt
 import matplotlib.pyplot as plt
-from math import pi
 
+from math import pi
 from GHEtool.VariableClasses.PipeData._PipeData import _PipeData
 from GHEtool.VariableClasses.FluidData import FluidData
 
@@ -163,7 +163,7 @@ def pressure_drop(self, fluid_data: FluidData, borehole_length: float) -> float:
 
         # add 0.2 for the local losses
         # (source: https://www.engineeringtoolbox.com/minor-loss-coefficients-pipes-d_626.html)
-        return ((fd * (borehole_length * 2) / (2 * self.r_in) + 0.2) * fluid_data.rho * V ** 2 / 2) / 1000
+        return ((fd * (borehole_length * 2) / (2 * self.r_in) + 0.0) * fluid_data.rho * V ** 2 / 2) / 1000
 
     def draw_borehole_internal(self, r_b: float) -> None:
         """

GHEtool/test/unit-tests/test_pressure_drop.py

@@ -0,0 +1,35 @@
+import numpy as np
+
+from GHEtool import *
+from GHEtool.Methods.pressure_drop_calculation import calculate_pressure_drop_horizontal, calculate_total_pressure_drop, \
+    create_pressure_drop_curve
+
+
+def test_horizontal():
+    fluid_data = FluidData(0.2, 0.568, 998, 4180, 1e-3)
+
+    assert np.isclose(calculate_pressure_drop_horizontal(fluid_data, 0.02 - 0.0037 / 2, 15, 0), 0.26307939880441045)
+    assert np.isclose(calculate_pressure_drop_horizontal(fluid_data, 0.02 - 0.0037 / 2, 15, 2), 0.3005010707434382)
+
+
+def test_total_pressure_drop():
+    single_u = SingleUTube(1.5, 0.013, 0.016, 0.4, 0.035)
+    double_u = DoubleUTube(1.5, 0.013, 0.016, 0.4, 0.035)
+    fluid_data = FluidData(0.3, 0.568, 998, 4180, 1e-3)
+
+    assert np.isclose(calculate_total_pressure_drop(single_u, fluid_data, 100, 0.02 - 0.0037 / 2, 10, 2),
+                      35.307092460895696)
+    assert np.isclose(calculate_total_pressure_drop(double_u, fluid_data, 100, 0.02 - 0.0037 / 2, 10, 2),
+                      11.139813565855187)
+
+
+def test_range_pressure_drop():
+    single_u = SingleUTube(1.5, 0.013, 0.016, 0.4, 0.035)
+    fluid_data = FluidData(0.2, 0.568, 998, 4180, 1e-3)
+
+    pressure, _ = create_pressure_drop_curve(single_u, fluid_data, 100, 0.02 - 0.0037 / 2, 10, 2)
+    assert np.allclose(pressure, np.array(
+        [0, 0.25311388, 0.50658373, 0.76040955, 1.90081784, 2.79351152, 3.81007873, 4.95814128, 6.23317941,
+         7.63146176, 9.14983034, 10.78556091, 12.53626754, 14.39983464, 16.37436709, 18.45815002, 20.64962988,
+         22.94737642, 25.3500745, 27.85650679, 30.46554156, 33.1761225, 35.98726063, 38.89802652, 41.90754461,
+         45.0149878, 48.21957292, 51.52055679, 54.9172327, 58.40892744]))