Chris Perdue wrote:

That's your wintertime meltdown calc, 73 vs 150 F. You are welcome.

In summertime, we might see (90+45xR2-90)/(R1+R2) = 30 Btu/h-ft^2 of
heatflow with a temperature near the screen of 90+30xR1 = 120 F, if
the storm windows stay closed.

Of course they needn't.

i'm welcome?

Sure. You said thanks. I said you are welcome.

either you need to reword or clarify because it makes no sense...

Perhaps not. It takes two to make sense.

all this talk of "at the screen"....the screen is on the *OUTSIDE* of
the airspace between the window and storm window...

Why didn't you say so? My screens are *****INSIDE***** the storms!!!

this is not even relevant to the heat buildup INSIDE the airspace...

Of course it is. Screens block sun. Interior screens warm
spaces between glass. Exterior screens cool them.

which where temps DO get hot enough to warp vinyl...

"Which where?" I suppose you could melt vinyl on a hot sunny day, with lots
of dark trim surface, if you were dumb enough to leave the storm windows
closed with no screen on the outside.

....who gives a rats ass about how much heat is transfered OUT the
storm when we are trying to stop damage to the window?

People who understand Ohm's law for heatflow. If an interior screen absorbs
20% of the 90% of full sun (250 Btu/h-F-ft^2) that enters an R1 storm window,
ie 0.2x0.9x250 = 45 Btu/h-ft^2, with 30 F outdoor air and 70 F room air
behind an R2 window, we have (viewed in a fixed font like Courier):

T = temp between window and storm
|
R2 | R1
70 F ---www---*--X--www--- 30 F
|
45 Btu/h | Temporarily opening the circuit at X, we can easily model
--- | the part to the left of X with a Thevenin equivalent...
|--|--|-- Opening the current source, some of us see that Rt=R2.
--- The open-circuit voltage Vt = 70+45xR2 = 160 F.

T
Rt=R2 | R1
---www---*--X--www--- 30 F
| I -- I = (160-30)/(R1+R2) = 43.3 F,
--- Vt = 160 F
- so T = 30+43.4xR1 = 73.3 F,
|
- not "150 or 160 F."

Have a nice day.

Nick