Determination of

RADIATIONSOLAR

By• Ahmed Radwan• Amr Mousa• Hazem Hamdy• Mostafa Elewa

𝜀 =2ℎ 𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑠𝑢𝑟𝑟 − 𝛼𝐺𝑠𝑜𝑙𝑎𝑟

2𝜎(𝑇𝑠𝑘𝑦4 + 𝑇𝑠𝑢𝑟𝑟

4 ) − 2𝜎𝑇𝑠𝑢𝑟𝑓4

Final Idea (The solar energy incident )

MethodologyMathematical equations

𝑄𝑖𝑛 = 𝑄𝑜𝑢𝑡

𝛼𝐺𝑠𝑜𝑙𝑎𝑟 + 𝜀𝜎𝑇𝑠𝑘𝑦4 + 𝜀𝜎𝑇𝑠𝑢𝑟𝑟

4 = 2𝜖𝜎𝑇𝑠𝑢𝑟𝑓4 + 2ℎ(𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑠𝑢𝑟𝑟)

h (heat conviction coefficient)

𝑅𝑒 =𝑉𝐿

𝑣=

5 ∗ 0.12

1.7 ∗ 10−5= 35.25 ∗ 103

𝑁𝑢 =ℎ𝐿

𝐾= 0.664 𝑅𝑒 𝑃𝑟 1 3

Martial Parameters

𝜀 = 0.09 𝑎𝑛𝑑 𝛼 = 0.525

• Commercial Aluminum

Tsky

𝑇𝑠𝑘𝑦 =4 Ԑ𝑠𝑇𝑎𝑖𝑟

Ԑ𝑠 = 0.77 + 0.0038 𝑇𝑑𝑝

The value of Tsky depends on the atmospheric conditions.

It ranges from about 230 K for cold, clear-sky conditions

to about 285 K for warm, cloudy-sky conditions.

MethodologyI. Hardware

Lm35 temperature sensors with Arduino.

MethodologyI. Hardware

MethodologyII. Software

Experiment Steps

To calculate the two parts of the G solar we first poisoned our base to take angle theta = 90 with the sun as cos (90) = 0 so G solar = G diffuse

We then calculate data using lab View program which we will explain later that collect data and calculate mean value

Second with the base at angle 30 with earth we calculate sun angle at this time and we get the angle between sun and the aluminum plate to be 18 degree

𝑄𝑖𝑛 = 𝑄𝑜𝑢𝑡

𝛼𝐺𝑠𝑜𝑙𝑎𝑟 + 𝜀𝜎𝑇𝑠𝑘𝑦4 + 𝜀𝜎𝑇𝑠𝑢𝑟𝑟

4 = 2𝜖𝜎𝑇𝑠𝑢𝑟𝑓4 + 2ℎ(𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑠𝑢𝑟𝑟)

Results

𝐺𝑠𝑜𝑙𝑎𝑟 = 2𝜀𝜎𝑇𝑠𝑢𝑟𝑓

4 + 2ℎ 𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑠𝑢𝑟𝑟 − 2𝜀𝜎(𝑇𝑠𝑘𝑦4 + 𝑇𝑠𝑢𝑟𝑟

4

𝛼

𝐺𝑠𝑜𝑙𝑎𝑟 = 1.944 ∗ 10−8 𝑇𝑠𝑢𝑟𝑓4 − 𝑇𝑠𝑘𝑦

4 − 𝑇𝑠𝑢𝑟𝑟4 + 94.66(𝑇𝑠𝑢𝑟𝑓 − 𝑇𝑠𝑢𝑟𝑟

𝑇𝑠𝑘𝑦 = 0.86 𝑇𝑎𝑖𝑟

𝑮𝑫𝒊𝒇𝒇𝒖𝒔𝒆 = 𝟐𝟐𝟔. 𝟖𝟓 𝑾/𝒎𝟐

𝑮𝑫𝒊𝒓𝒆𝒄𝒕 = 𝟐𝟔𝟓. 𝟔𝟔𝑾/𝒎𝟐

Future Work

Knowing the G solar direct and diffuse for specific material, we could replace the plate on the base with any unknown material we want to know its emissivity and calculate it using same equations.

Make the LabVIEW program fully automated in gathering

information about the weather and the surrounding environment with very few inputs

References

I. Yunus A. Gengel, and Robert Turner, " Fundamentals of Engineering Thermodynamics ",

McGraw Hill,2014 , 8th Edition

II. Yunus A. Cengel, “Heat and Mass Transfer, A Practical Approach,” 3rd Edition, McGraw Hill,

2006.

III. Sultan A (2004) Absorption/regeneration non-conventional system for water extraction from

atmospheric air. Renew Energy 29:1515–1535

IV. Berdahl P, Fromberg R (1982) The thermal radiance of clear skies. Sol Energy 29:299–314

V. Khedari J, Waewsak J, Thepa S, Hirunlabh J (2000) Field investigation of night radiation cooling

under tropical climate. Renew Energy 20:183–193

VI. Cooper PI, Christie EA, Dunkle RV (1981) A method of measuring sky temperature. Sol Energy

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VII. Enz JW, Klink JC, Baker DG (1975) Solar radiation effects on pyrgeometer performance. J Appl

Meteor 19:1297