A parcel locker sitting in the desert sun bakes. This app shows how hot each side of the locker gets, how hot the screen glass gets, how hot the air inside the screen console gets, and how hot the strip of door control boards along the top gets, hour by hour, for any day of the year.
Turn the locker to face a different direction, add shade, change the paint, change how much heat the electronics make, or turn on an air conditioner, and see what each change does.
Why bother?
Picking where a locker goes and which way it faces costs almost nothing before install. Fixing heat damage after install costs a truck roll every time. This shows which placements will cook the screen and the boards and which ones stay workable.
How to read it
The 3D view shows the locker, the sun, and the shadows at the time on the slider. With Heat view on, every surface is tinted by how hot it is: pale blue is cool, yellow is warm, red is very hot. Heat builds toward the top of each section, spreads out from the screen console into the modules beside it, and shows on the back of the console where the gear sits. Tap Back to look at the back of the locker.
The chart shows the whole day. The dashed lines are your limits. Anything above them is a problem hour.
Okay, now the details
Sun position comes from the NOAA solar equations for the latitude and longitude you enter. Clear sky sunlight comes from the ASHRAE monthly clear sky model, split into direct beam, sky light, and light bounced off the ground.
Each outside face gets a sol air temperature: outside air plus the sunlight that face absorbs, divided by how fast wind carries heat off it. The roof also loses a little heat to the open night sky.
The locker is three air spaces. The screen console runs the full depth of its module and holds the screen, computer, boards, router, and power strip, and its back louvers trade air with the outside. The locker bays beside it hold no powered gear. The board strip is the closed box along the top of every module that holds the door control boards, and it sits right under the roof. Each space gains heat through its walls, trades heat with its neighbors through shared steel panels, and responds with a time lag you can set.
The hat on top shades the roof and casts a shadow down every side. The higher the sun, the farther down that shadow reaches, so with the sun straight overhead the sides are fully shaded. The board strip gets shaded first because it is at the top. The awning works the same way on the front with a longer reach. Full shade blocks direct sun on every face and part of the sky light. Indoor lobby removes the sun and uses the lobby air temperature.
Screen glass temperature balances the sun the glass absorbs and the outside air against the hot console air behind it.
Outside air follows the average daily high and low for each month in the Las Vegas valley, with the low near dawn and the high mid afternoon. Heat wave add pushes the whole day hotter.
The heat tint inside each section rises toward the top in step with how much hotter that section runs than the air outside, and the console heat fades out across the neighboring modules. This tint is for reading the picture; the numbers in the readouts come from the three air space model.
All of this assumes clear sky. Clouds, dust storms, nearby walls, and parked cars are not modeled.