# Effect of solar flux.xls

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### Description

KNOWN: Surface area of electronic package and power dissipation by the electronics. Surface emissivity and absorptivity to solar radiation. Solar Flux.
FIND: Surface temperature without and with incident solar radiation.
ASSUMPTIONS: Steady State conditions.
KEYWORDS: Stefan -Boltzman Constant, Emissivity, Absorptivity, Power dissipation, Solar Flux.

Calculation Reference
Fundamentals of Heat and Mass Transfer - Frank P. Incropera

To determine the surface temperature of an electronic package without and with incident solar radiation, considering power dissipation, surface emissivity, absorptivity, and solar flux, you can follow these steps:

1. Calculate the net power dissipation: The net power dissipation of the electronics can be calculated by subtracting the power absorbed from solar radiation from the total power dissipated:

Net Power Dissipation = Total Power Dissipation - Power Absorbed from Solar Radiation

2. Calculate the surface temperature without solar radiation: Using the net power dissipation, you can calculate the surface temperature of the electronic package without considering solar radiation. This can be done using the Stefan-Boltzmann Law:

Surface Temperature without Solar Radiation = (Net Power Dissipation / (ε * σ * Surface Area))^0.25

Where ε is the emissivity of the surface, σ is the Stefan-Boltzmann constant (approximately 5.67 x 10^-8 W/(m^2·K^4)), and Surface Area is the surface area of the electronic package.

3. Calculate the power absorbed from solar radiation: Multiply the solar flux by the absorptivity of the surface to calculate the power absorbed from solar radiation:

Power Absorbed from Solar Radiation = Solar Flux * Absorptivity * Surface Area

Where Solar Flux is the incident solar flux on the surface and Absorptivity is the absorptivity of the surface to solar radiation.

4. Calculate the surface temperature with solar radiation: Incorporate the power absorbed from solar radiation into the net power dissipation and use the Stefan-Boltzmann Law to calculate the surface temperature of the electronic package with incident solar radiation:

Surface Temperature with Solar Radiation = ((Net Power Dissipation + Power Absorbed from Solar Radiation) / (ε * σ * Surface Area))^0.25

Where Net Power Dissipation is the net power dissipation calculated in step 1, Power Absorbed from Solar Radiation is the power absorbed from solar radiation calculated in step 3, ε is the emissivity of the surface, σ is the Stefan-Boltzmann constant, and Surface Area is the surface area of the electronic package.

By following these steps, you can determine the surface temperature of the electronic package both without and with incident solar radiation, considering power dissipation, surface emissivity, absorptivity, and solar flux. These calculations provide insights into the thermal behavior of the electronic package under different conditions.

24 Jan 2007
18 Jul 2023
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