How to Calculate and Solve for Internal Latent Heat | Enthalpy
Last Updated on June 6, 2022
The internal latent heat is illustrated by the image below.
To compute for internal latent heat, four essential parameters are needed and these parameters are Enthalpy of Vapourization (hfg), Specific Volume of Gas (vg), Pressure (P) and J.
The formula for calculating internal latent heat:
L = hfg – Pvg / J
Where:
L = Internal Latent Heat
hfg = Enthalpy of Vapourization
vg = Specific Volume of Gas
P = Pressure
Given an example;
Find the internal latent heat when the enthalpy of vapourization is 22, the enthalpy of vapourization is 12, the specific volume of gas is 10 and J is 1.
This implies that;
hfg = Enthalpy of Vapourization = 22
vg = Specific Volume of Gas = 12
P = Pressure = 10
L = hfg – Pvg / J
L = 22 – 10 x 12 / 1
L = 22 – 120 / 1
L = 22 – 120
L = -98
Therefore, the internal latent heat is -98kg.
Calculating the Enthalpy of Vapourization when the Internal Latent Heat, the Specific Volume of Gas and the Pressure is Given.
hfg = L + Pvg / J
Where:
hfg = Enthalpy of Vapourization
L = Internal Latent Heat
vg = Specific Volume of Gas
P = Pressure
Let’s solve an example;
Find the enthalpy of vapourization when the internal latent heat is 30, the specific volume of gas is 10 and the pressure is 5.
This implies that;
L = Internal Latent Heat = 30
vg = Specific Volume of Gas = 10
P = Pressure = 5
hfg = L + Pvg / J
hfg = 30 + (10)(5) / 1
hfg = 30 + 50 / 1
hfg = 30 + 50
hfg = 80
Therefore, the enthalpy of vapourization is 80J/Kg.
Calculating the Pressure when the Internal Latent Heat, the Enthalpy of Vapourization and the Specific Volume of Gas is Given.
P = hfg – L / vg x J
Where:
P = Pressure
L = Internal Latent Heat
hfg = Enthalpy of Vapourization
vg = Specific Volume of Gas
Let’s solve an example;
Find the pressure when the internal latent heat is 24, the enthalpy of vapourization is 35 and the specific volume of gas is 10.
This implies that;
L = Internal Latent Heat = 24
hfg = Enthalpy of Vapourization = 35
vg = Specific Volume of Gas = 10
P = hfg – L / vg x J
P = 35 – 24 / 10 x 1
P = 1.1 x 1
P = 1.1
Therefore, the pressure is 1.1J/Kg.
Calculating the Specific Volume of Gas when the Internal Latent Heat, the Enthalpy of Vapourization and the Pressure is Given.
vg = hfg – L / P x J
Where:
vg = Specific Volume of Gas
L = Internal Latent Heat
hfg = Enthalpy of Vapourization
P = Pressure
Let’s solve an example;
Find the specific volume of gas when the internal latent heat is 20, the enthalpy of vapourization is 40 and the pressure is 2.
This implies that;
L = Internal Latent Heat = 20
hfg = Enthalpy of Vapourization = 40
P = Pressure = 2
vg = hfg – L / P x J
vg = 40 – 20 / 2 x 1
vg = 20 / 2 x 1
vg = 10 x 1
vg = 10
Therefore, the specific volume of gas is 10J/Kg.
Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the internal latent heat.
To get the answer and workings of the internal latent heat using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.
You can get this app via any of these means:
Web – https://www.nickzom.org/calculator-plus
To get access to the professional version via web, you need to register and subscribe to have utter access to all functionalities.
You can also try the demo version via https://www.nickzom.org/calculator
Android (Paid) – https://play.google.com/store/apps/details?id=org.nickzom.nickzomcalculator
Android (Free) – https://play.google.com/store/apps/details?id=com.nickzom.nickzomcalculator
Apple (Paid) – https://itunes.apple.com/us/app/nickzom-calculator/id1331162702?mt=8
Once, you have obtained the calculator encyclopedia app, proceed to the Calculator Map, then click on Materials and Metallurgical under Engineering.
Now, Click on Chemical Reaction Thermodynamics under Materials and Metallurgical
Now, Click on Enthalpy under Chemical Reaction Thermodynamics
Now, Click on Internal Latent Heat under Enthalpy
The screenshot below displays the page or activity to enter your values, to get the answer for the internal latent heat according to the respective parameter which is the Enthalpy of Vapourization (hfg), Specific Volume of Gas (vg), Pressure (P) and J.
Now, enter the values appropriately and accordingly for the parameters as required by the Enthalpy of Vapourization (hfg) is 22, Specific Volume of Gas (vg) is 12, Pressure (P) is 10 and J is 1.
Finally, Click on Calculate
As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the internal latent heat and presents the formula, workings and steps too.