Electronics in a hot climate

The amount of sunlight reaching a horizontal surface at Earth's surface is called insolation, measured in units of watts per square meter (W/m2).

See pages 18-21 of Bird's "A Simplified Clear Sky Model for Direct and Diffuse Insolation on Horizontal surfaces"

Around midday on a summer day in temperate climates, roughly 1 kW/m2 of power reaches Earth's surface. About 57% of that is IR (0.7um or greater).

You'd add this burden to the total power being dissipated by your package.

Solar reflectivity, or albedo, is colour and wavelength dependent. Grey will reflect roughly 25% of most wavelengths between 0.4 and

A go-anywhere package will have a go-anywhere colour. Point that out to 'he who must be obeyed'.

RL

That often alleviates some problems but creates others. Ability to dissipate heat goes WAY down. As somebody else mentioned, moisture in trapped atmosphere can cause problems.

Will the plastic box deform before the pressure release valve releases?

If the battery vents inside of the sealed box, will that vented gas attack stuff it's trapped with?

Failure analysis for this project would be interesting.

Yup.

That could backfire, keeping moist humid air trapped as the temperature drops at night, creating dew inside the box.

Same 75% from .5 um upwards for brighter/lemon/canary yellow, same 75% from .53-.55 um upwards for "school bus yellow" to amber-orange-yellow.

Power spectra is mostly towards the visible end of the IR spectrum - shorter wavelengths. So, worst case 250W/m^2 is collected by a clean yellow box.

Assuming a surface temperature rise of between 0.8 to 1.2 degrees per mW/cm, that looks like a potential additional rise of 20-30degrees on the surface that is directly exposed at noon, if it cannot be redistributed over the entire package surface area. That would depend on box material. Coated with dust, this could double.

Before a first approximation of internal air temperature can be made, you'd need more info on package shape and mounting orientation, box material, wall thickness and internal power loss budget.

RL

"Bill Bowden"

No Phil, f*ck off and die is a confusing term. Most people don't know the procedure. The correct term is "Eat Shit and Die" which everybody understands.

The term " FOAD " is well accepted and understood.

In any case, eating shit is not guaranteed to prove fatal.

Sticking one's head in a microwave oven might prove fatal - if the door interlocks were over-ridden.

So maybe I should try " Go Fry Your Brains Fuckhead"

GFYBF does have a bit of a ring to it......

.... Phil

I was at a party once where someone microwaved a shit. Nasty! I believe the microwave was dicarded after this incident.

"Dennis"

Makes shit hitting the fan look very tame ....

... Phil

I suspect the cavity would be so badly de-tuned that no appreciable exposure would occur. Not that I plan to to home-brew the experiment.... :)

Damn, that's like cleaning out a well used coffee pot!

Jamie

Did the shit go by the name Nymbecile?

That's just wrong!