The image above represents radiosity. To calculate radiosity, three essential parameters are needed and these parameters are Total Emissive Power (e), Reflectivity (ρ) and Total Irradiation (G).
The formula for calculating radiosity:
J = e + ρG
Where:
J = Radiation Heat Transfer
e = Total Emissive Power
ρ = Reflectivity
G = Total Irradiation
Let’s solve an example;
Find the radiation heat transfer when the total emissive power is 12, the reflectivity is 10 and the total irradiation is 20.
This implies that;
e = Total Emissive Power = 12
ρ = Reflectivity = 10
G = Total Irradiation = 20
J = e + ρG
J = 12 + (10)(20)
That is, J = 12 + 200
J = 212
Therefore, the radiosity is 212 W/m².
Calculating the Total Emissive Power when the Radiosity, the Reflectivity and the Total Irradiation are Given
e = J – ρG
Where:
e = Total Emissive Power
J = Radiation Heat Transfer
ρ = Reflectivity
G = Total Irradiation
Let’s solve an example;
Find the total emissive power when the radiation heat transfer is 32, the reflectivity is 10 and the total irradiation is 2.
This implies that;
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J = Radiation Heat Transfer = 32
ρ = Reflectivity = 10
G = Total Irradiation = 2
e = J – ρG
Then, e = 32 – (10)(2)
e = 32 – 20
e = 12
Therefore, the total emissive power is 12.
Read more: How to Calculate and Solve for Energy Transfer by Radiation | Radiation Heat Transfer
Calculating the Reflectivity when the Radiosity, the Total Emissive Power and the Total Irradiation are Given
ρ = J – e / G
Where:
ρ = Reflectivity
J = Radiation Heat Transfer
e = Total Emissive Power
G = Total Irradiation
Let’s solve an example;
Find the reflectivity when the radiation heat transfer is 28, the total emissive power is 10 and the total irradiation is 4.
This implies that;
J = Radiation Heat Transfer = 28
e = Total Emissive Power = 10
G = Total Irradiation = 4
ρ = J – e / G
ρ = 28 – 10 / 4
Then, ρ = 18 / 4
ρ = 4.5
Therefore, the reflectivity is 4.5.
Calculating the Total Irradiation when the Radiosity, the Total Emissive Power and the Reflectivity are Given
G = J – e / ρ
Where:
G = Total Irradiation
J = Radiation Heat Transfer
e = Total Emissive Power
ρ = Reflectivity
Let’s solve an example;
Find the total irradiation when the radiation heat transfer is 44, the total emissive power is 14 and the reflectivity is 2.
This implies that;
J = Radiation Heat Transfer = 44
e = Total Emissive Power = 14
ρ = Reflectivity = 2
G = J – e / ρ
So, G = 44 – 14 / 2
G = 30 / 2
G = 15
Therefore, the total irradiation is 15.
Read more: How to Calculate and Solve for Emissive Power | Radiation Heat Transfer
How to Calculate Radiosity Using Nickzom Calculator
Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the radiosity.
To get the answer and workings of the radiosity 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 for NGN 2,000 per annum 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 Radiation Heat Transfer under Materials and Metallurgical
Now, Click on Radiosity under Radiation Heat Transfer
The screenshot below displays the page or activity to enter your values, to get the answer for the radiosity according to the respective parameter which is the Total Emissive Power (e), Reflectivity (ρ) and Total Irradiation (G).
Now, enter the values appropriately and accordingly for the parameters as required by the Total Emissive Power (e) is 12, Reflectivity (ρ) is 10 and Total Irradiation (G) is 20.
Finally, Click on Calculate
As you can see from the screenshot above, Nickzom Calculator– The Calculator Encyclopedia solves for the radiosity and presents the formula, workings and steps too.
