# Install CoolProp if it is missing (e.g., on Google Colab)
try:
import CoolProp
except ImportError:
%pip install -q CoolProp
import CoolProp.CoolProp as CP
import ipywidgets as widgets
from IPython.display import display, clear_output
import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
# --- 1. Configuration & Constants ---
fluids = ['Water', 'R134a', 'Air', 'Nitrogen', 'CO2', 'Ammonia', 'Ethanol', 'Methane']
# Input pairs (CoolProp Keys)
input_pairs = {
'Temperature (K) & Pressure (Pa)': 'TP',
'Temperature (K) & Quality (0-1)': 'TQ',
'Pressure (Pa) & Quality (0-1)': 'PQ',
'Pressure (Pa) & Enthalpy (J/kg)': 'PH',
'Pressure (Pa) & Entropy (J/kg/K)': 'PS',
'Temperature (K) & Density (kg/m3)': 'TD',
}
# --- 2. Helper Functions ---
def convert_units(data_dict, unit_system):
"""Converts a dictionary of SI properties to the target unit system."""
d = data_dict.copy()
if unit_system == 'SI':
# Convert J to kJ for readability
d['P'] = d['P [Pa]'] / 1000.0 # kPa
d['T'] = d['T [K]']
d['v'] = d['v [m3/kg]']
d['u'] = d['u [J/kg]'] / 1000.0 # kJ/kg
d['h'] = d['h [J/kg]'] / 1000.0 # kJ/kg
d['s'] = d['s [J/kg/K]'] / 1000.0 # kJ/kg-K
return d, {'P': 'kPa', 'T': 'K', 'v': 'm3/kg', 'u': 'kJ/kg', 'h': 'kJ/kg', 's': 'kJ/kg-K'}
elif unit_system == 'Imperial':
# Conversions
d['P'] = d['P [Pa]'] * 0.000145038 # psia
d['T'] = (d['T [K]'] - 273.15) * 1.8 + 32 # F
d['v'] = d['v [m3/kg]'] * 16.0185 # ft3/lb
d['u'] = d['u [J/kg]'] * 0.000429923 # Btu/lb
d['h'] = d['h [J/kg]'] * 0.000429923 # Btu/lb
d['s'] = d['s [J/kg/K]'] * 0.000238846 # Btu/lb-R
return d, {'P': 'psia', 'T': 'F', 'v': 'ft3/lb', 'u': 'Btu/lb', 'h': 'Btu/lb', 's': 'Btu/lb-R'}
def get_phase_desc(fluid, T, P):
try:
T_crit = CP.PropsSI('Tcrit', fluid)
P_crit = CP.PropsSI('Pcrit', fluid)
if T > T_crit and P > P_crit:
return "Supercritical"
try:
Psat = CP.PropsSI('P', 'T', T, 'Q', 0, fluid)
if abs(P - Psat) < 1e-1:
return "Saturation"
elif P > Psat:
return "Compressed Liquid"
else:
return "Superheated Vapor"
except:
return "Fluid"
except:
return "Unknown"
def calculate_state(fluid, pair_key, val1, val2):
inputs = {'TP': ('T', 'P'), 'TQ': ('T', 'Q'), 'PQ': ('P', 'Q'),
'PH': ('P', 'H'), 'PS': ('P', 'S'), 'TD': ('T', 'D')}
param1_name, param2_name = inputs[pair_key]
try:
# Calculate in SI Base Units
T = CP.PropsSI('T', param1_name, val1, param2_name, val2, fluid)
P = CP.PropsSI('P', param1_name, val1, param2_name, val2, fluid)
D = CP.PropsSI('D', param1_name, val1, param2_name, val2, fluid)
H = CP.PropsSI('H', param1_name, val1, param2_name, val2, fluid)
S = CP.PropsSI('S', param1_name, val1, param2_name, val2, fluid)
U = CP.PropsSI('U', param1_name, val1, param2_name, val2, fluid)
Q = CP.PropsSI('Q', param1_name, val1, param2_name, val2, fluid)
v = 1.0 / D if D != 0 else 0
if 0 <= Q <= 1:
phase = f"Two-Phase (x={Q:.4f})"
else:
phase = get_phase_desc(fluid, T, P)
Q = np.nan
return {
'T [K]': T, 'P [Pa]': P, 'v [m3/kg]': v, 'u [J/kg]': U,
'h [J/kg]': H, 's [J/kg/K]': S, 'Quality (x)': Q, 'Phase': phase
}
except Exception as e:
return {'Error': str(e)}
# --- 3. Visualization Functions ---
def plot_diagrams(fluid, state1, state2, unit_system):
"""Plots both T-s and P-v diagrams side-by-side."""
# Setup Data for Dome
T_crit = CP.PropsSI('Tcrit', fluid)
T_min = CP.PropsSI('Tmin', fluid)
T_range = np.linspace(T_min, T_crit - 0.5, 50)
# Calculate Saturation Lines (SI)
s_liq_si = [CP.PropsSI('S', 'T', t, 'Q', 0, fluid) for t in T_range]
s_vap_si = [CP.PropsSI('S', 'T', t, 'Q', 1, fluid) for t in T_range]
v_liq_si = [1/CP.PropsSI('D', 'T', t, 'Q', 0, fluid) for t in T_range]
v_vap_si = [1/CP.PropsSI('D', 'T', t, 'Q', 1, fluid) for t in T_range]
p_sat_si = [CP.PropsSI('P', 'T', t, 'Q', 0, fluid) for t in T_range]
# Convert Dome Data if needed
if unit_system == 'Imperial':
# T-s conversions
T_plot = [(t - 273.15)*1.8 + 32 for t in T_range]
s_liq = [s * 0.000238846 for s in s_liq_si]
s_vap = [s * 0.000238846 for s in s_vap_si]
# P-v conversions
p_plot = [p * 0.000145038 for p in p_sat_si]
v_liq = [v * 16.0185 for v in v_liq_si]
v_vap = [v * 16.0185 for v in v_vap_si]
units = {'T': 'F', 'P': 'psia', 'v': 'ft3/lb', 's': 'Btu/lb-R'}
else:
T_plot = T_range
s_liq = [s/1000 for s in s_liq_si]
s_vap = [s/1000 for s in s_vap_si]
p_plot = [p/1000 for p in p_sat_si] # kPa
v_liq = v_liq_si
v_vap = v_vap_si
units = {'T': 'K', 'P': 'kPa', 'v': 'm3/kg', 's': 'kJ/kg-K'}
# Prepare Figure
fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(12, 5))
# --- Plot 1: T-s Diagram ---
ax1.plot(s_liq, T_plot, 'k-', alpha=0.5, label='Sat. Liq')
ax1.plot(s_vap, T_plot, 'k--', alpha=0.5, label='Sat. Vap')
ax1.set_xlabel(f"Entropy ({units['s']})")
ax1.set_ylabel(f"Temperature ({units['T']})")
ax1.set_title(f"T-s Diagram ({fluid})")
# --- Plot 2: P-v Diagram ---
ax2.plot(v_liq, p_plot, 'k-', alpha=0.5)
ax2.plot(v_vap, p_plot, 'k--', alpha=0.5)
ax2.set_xlabel(f"Specific Volume ({units['v']})")
ax2.set_ylabel(f"Pressure ({units['P']})")
ax2.set_xscale('log') # Log scale for volume is essential
ax2.set_title(f"P-v Diagram ({fluid})")
# Plot Points
for state, color, label in [(state1, 'r', '1'), (state2, 'b', '2')]:
if 'Error' not in state:
# Convert single state point
s_conv, _ = convert_units(state, unit_system)
# T-s Point
ax1.plot(s_conv['s'], s_conv['T'], marker='o', color=color, label=f"State {label}")
# P-v Point
ax2.plot(s_conv['v'], s_conv['P'], marker='o', color=color, label=f"State {label}")
ax1.legend()
ax1.grid(True, alpha=0.3)
ax2.grid(True, alpha=0.3, which="both")
plt.tight_layout()
plt.show()
# --- 4. Interface & Logic ---
w_fluid = widgets.Dropdown(options=fluids, value='Water', description='Fluid:')
w_units = widgets.ToggleButtons(options=['SI', 'Imperial'], value='SI', description='Output Units:')
# State 1 Widgets
w_pair1 = widgets.Dropdown(options=input_pairs, value='TP', description='State 1 Inputs:')
w_val1_1 = widgets.FloatText(description='Prop 1:', value=300)
w_val1_2 = widgets.FloatText(description='Prop 2:', value=101325)
# State 2 Widgets
w_pair2 = widgets.Dropdown(options=input_pairs, value='TP', description='State 2 Inputs:')
w_val2_1 = widgets.FloatText(description='Prop 1:', value=400)
w_val2_2 = widgets.FloatText(description='Prop 2:', value=101325)
btn_calc = widgets.Button(description='Calculate', button_style='primary')
out_display = widgets.Output()
def on_calc_clicked(b):
with out_display:
clear_output()
# Calculate Base States (SI)
s1 = calculate_state(w_fluid.value, w_pair1.value, w_val1_1.value, w_val1_2.value)
s2 = calculate_state(w_fluid.value, w_pair2.value, w_val2_1.value, w_val2_2.value)
if 'Error' in s1: print(f"Error State 1: {s1['Error']}"); return
if 'Error' in s2: print(f"Error State 2: {s2['Error']}"); return
# Convert for Display
sys = w_units.value
s1_disp, u_labels = convert_units(s1, sys)
s2_disp, _ = convert_units(s2, sys)
# Create Table Data
props = ['T', 'P', 'v', 'u', 'h', 's']
prop_names = [f"Temperature [{u_labels['T']}]", f"Pressure [{u_labels['P']}]",
f"Spec. Vol [{u_labels['v']}]", f"Int. Energy [{u_labels['u']}]",
f"Enthalpy [{u_labels['h']}]", f"Entropy [{u_labels['s']}]"]
data = {'Property': prop_names + ['Quality (x)', 'Phase']}
data['State 1'] = [s1_disp[p] for p in props] + [s1['Quality (x)'], s1['Phase']]
data['State 2'] = [s2_disp[p] for p in props] + [s2['Quality (x)'], s2['Phase']]
df = pd.DataFrame(data)
# Calculate Delta
deltas = []
for i in range(len(props)):
deltas.append(data['State 2'][i] - data['State 1'][i])
deltas.extend(['', '']) # No delta for Q or Phase
df['Delta (2-1)'] = deltas
# Display Table
display(df.style.format(precision=4, subset=['State 1', 'State 2', 'Delta (2-1)']))
# Plot Diagrams
plot_diagrams(w_fluid.value, s1, s2, sys)
# Reference State Note
display(widgets.HTML(f"""
<div style="background-color: #e7f3fe; border-left: 6px solid #2196F3; padding: 10px; margin-top: 10px;">
<strong>Important Note on Reference States:</strong><br>
Values for Energy (u, h) and Entropy (s) are calculated relative to a reference state where h=0 and s=0.
CoolProp often uses the IIR standard (saturated liquid at 0°C) or NBP (Normal Boiling Point) depending on the fluid.
<br><strong>Warning:</strong> The <em>absolute</em> values shown here may differ from your textbook tables if the reference states do not match.
However, the <strong>Difference (Delta)</strong> values should match closely, as differences are independent of the reference state.
</div>
"""))
btn_calc.on_click(on_calc_clicked)
# Layout
ui = widgets.VBox([
widgets.HTML("<h2>Thermodynamic Property Calculator</h2>"),
widgets.HBox([w_fluid, w_units]),
widgets.HTML("<i><b>Note:</b> Please enter input values in SI Units (K, Pa, J/kg). Output will convert based on toggle.</i>"),
widgets.HTML("<hr>"),
widgets.HBox([
widgets.VBox([widgets.HTML("<b>State 1</b>"), w_pair1, w_val1_1, w_val1_2]),
widgets.VBox([widgets.HTML("<b>State 2</b>"), w_pair2, w_val2_1, w_val2_2])
]),
widgets.HTML("<br>"),
btn_calc,
out_display
])
display(ui)
