Specific Enthalpy#

A simplified equation by Kostyrko and Pluciennik is used for the specific enthalpy of saturated water.

\[h_s = d_1 + d_2\cdot T + d_3\cdot T^2 + d_4\cdot T^3 + d_5\cdot T^4 + d_6\cdot T^5 \tag{5}\]

where

Var

Description

hs

is the specific enthalpy water, kJ/kg

T

is temperature of the water °C

d1

is -2.844699e-02

d2

is 4.211925

d3

is -1.017034e-03

d4

is 1.311054e-05

d5

is -6.756469e-08

d6

is 1.724481e-10

which should give an almost linear plot.

Show/Hide Code 05sp_enthalpy.py 
import altair as alt
import numpy as np
import pandas as pd

T = np.linspace(0, 30, 31)

hs = -2.844699e-02 + 4.211925 * T - 1.017034e-03 * np.power(T, 2) + \
    1.311054e-05 * np.power(T, 3) - 6.756469e-08 * np.power(T, 4) + \
    1.724481e-10 * np.power(T, 5)

source = pd.DataFrame({
  'Temperature °C': T,
  'Specific Enthalpy of Liquid Water': hs
})

chart = alt.Chart(source).mark_line().encode(
    x=alt.X('Temperature °C', axis=alt.Axis(title='Temperature °C')),
    y=alt.Y('Specific Enthalpy of Liquid Water', axis=alt.Axis(title='Spec Enthalpy kJ/kg')),
    tooltip=['Temperature °C', alt.Tooltip('Specific Enthalpy of Liquid Water', format='.2f')]
).properties(
        title={
            "text": "Specific Enthalpy of Liquid Water",
            "color": "#282828"
        }
    )

chart.save('sp_enthalpy.html')

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