Need some basic mathematics help, yo

[KrazyHorse]

Originally posted by Zylka


I've already accounted for thicknesses in arriving at each elements' R.

As they have been arrived - element 1 has a 4.7% worth of the entire walls' insulative valie. Element 2 has a 3.9% worth of the entire walls' insulative value.

Using the forumla you find correct - the first element (thickness and Btu already accounted for), with a HIGHER proportion of the walls' overall insulation - LOSES more temperature than the lesser element of 3.9%. That does not make sense.

TEMPERATURE DOES NOT EQUAL HEAT. ALL SEGMENTS OF THE WALL ARE SEEING THE SAME HEAT FLOW THROUGH THEM.

[Zylka]

Originally posted by KrazyHorse

NO. THE FORMULA IS CORRECT. THICKER LAYERS OF INSULATION HAVE A GREATER CHANGE IN TEMPERATURE ACROSS THEM.

THE PERCENTAGE PROPORTIONS ARE NOT THICKNESS BASED.

The way I'm being asked to do this; a 1 inch layer of fibreglass will lose MORE temperature than a 1 inch layer of steel.

Let's do it this way:

Outside temp = -30, inside temp +22

If a 1 inch layer of fibreglass made up 90% of a walls overall insulative value, and a 1 inch layer of steel made up the other %10 - would you therefore say that the layer of fibreglass LOSES 46.8 degrees while the steel loses the final 5.2? Of course you wouldn't.

[KrazyHorse]

Just trust the ****ing formula, Zylka. It makes perfect sense. I've rederived it for you from the beginning. If you still don't believe it then that's your problem.

[KrazyHorse]

Originally posted by Zylka


THE PERCENTAGE PROPORTIONS ARE NOT THICKNESS BASED.

a) THEY BETTER DAMN WELL DEPEND ON THE THICKNESS OF EACH LAYER; R value = specific insulation value * thickness

b) IT DOESN'T MATTER.

[KrazyHorse]

Originally posted by Zylka
If a 1 inch layer of fibreglass made up 90% of a walls overall insulative value, and a 1 inch layer of steel made up the other %10 - would you therefore say that the layer of fibreglass LOSES 46.8 degrees while the steel loses the final 5.2? Of course you wouldn't.

YES I WOULD. STEEL IS A BAD INSULATOR. THEREFORE IT IS A GOOD CONDUCTOR. THEREFORE THE TEMPERATURE ACROSS A THIN LAYER OF STEEL IS RELATIVELY CONSTANT.

But **** it; I'm just a physicist. What the **** do I know about thermodynamics...

[Zylka]

.

[Asher]

What if the building was on Pluto?

[KrazyHorse]

Originally posted by Zylka
So you would indeed say that a 1 inch section of fibreglass would lose more than a 1 inch section of steel, if the fibreglass is quoted as 9 times more insulative?

Lose more what, you freak? Temperature?

Bullsh*t. If you don't know what you're doing wrong, I'll explain it to you after finding out tommorrow

Come back and apologise after your teacher tells you the formula is ****ing correct.

[Koyaanisqatsi]

Zylka, bigger temperature deltas are an indicator that it's a better insulator. Remember, you're measuring insulation--those deltas aren't being lost, they're being retained.

[Zylka]

Originally posted by KrazyHorse


Lose more what, you freak? Temperature?







Come back and apologise after your teacher tells you the formula is ****ing correct.

Alright, alright

So in this wall section, you would say that:

The temperature in the first section [cedar panels worth 4.7% of total insulation] drops 2.9 degrees; from 22degrees to 19.1 degrees.

From there, in the second section [gypsum board worth 3.9% of total insulation] the temperature drops an additional 2.4 degrees down to 16.7 degrees.

In the third section [An air space worth 45.5% of the total insulation] the temperature drops 23.7 degrees, or down to -7 degrees

(etc.)

It seems absolutely ridiculous to assert that something worth MORE of an overall insulative value is going to see a relative INCREASE in temperature drop..

Zylka, bigger temperature deltas are an indicator that it's a better insulator. Remember, you're measuring insulation--those deltas aren't being lost, they're being retained.

err

[Zylka]

I guess this visually confirms what you're arguing, KH. Rather than apologize though, I'm just going to call you a *ing jewbag and punch you in the teeth

PS. Habs are going nowhere

[joncha]

I LIKE TO TYPE IN ALL-CAPS. IS IT ALRIGHT WITH YOU GUYS IF I USE THIS THREAD TO DO IT?