Latent Heat#

The latent heat of vapourisation was calculated with the equation,

\[h_{fg} = h_{sv} - h_s\]

to create the approximate formula,

\[h_{fg} = a + b\cdot T + c\cdot T^{1.5} + d\cdot T^{2.5} + e\cdot T^3 \tag{7}\]

where

Var

Description

hfg

is the latent heat liquid water, kJ/kg

hsv

is the enthalpy of the vapour, kJ*K

hs

is the enthalpy of the liquid, kJ*K

T

is temperature of the water °C

a

is 2500.304

b

is -2.2521025

c

is -0.02146547

d

is 3.1750136e-04

e

is -2.8607959e-05
Show/Hide Code 07lat_ht.py 
import altair as alt
import numpy as np
import pandas as pd

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

hfg = 2500.304 - 2.2521025 * T - 0.02146547 * np.power(T, 1.5) + \
    3.1750136e-04 * np.power(T, 2.5) - 2.8607959e-05 * np.power(T, 3)

source = pd.DataFrame({
  'Temperature °C': T,
  'Latent Heat kJ/kg': hfg
})

chart = alt.Chart(source).mark_line().encode(
    x=alt.X('Temperature °C', axis=alt.Axis(title='Temperature °C')),
    y=alt.Y('Latent Heat kJ/kg', axis=alt.Axis(title='Latent Heat kJ/kg'),
           scale=alt.Scale(domain=(2420, 2510))
           ),
    tooltip=['Temperature °C', alt.Tooltip('Latent Heat kJ/kg', format='.1f')]
).properties(
        title={
            "text": "Latent Heat Evaporisation of Water",
            "color": "#282828"
        }
    )

chart.save('lat_heat.html')

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