Optimus, a waste on laptop, badly needed on desktop!

[yh125d]

what are you talking about? 1+2 = 3. you are saying 1+2 = 4... i don't get it.

You are calculating 1+2+3 year round, where the +2 is only present during 1/2 the year or so

What it should be (assuming your math was otherwise correct, which it isn't) would be (wattage1)x(time1) + (wattage2)x(time2)

Where time1 is the one year where the card is drawing 30w and time2 is the 1/2 year that there is added power usage due to the cooling. In your calculation you were using time1 in both places


Heres numbers to illustrate

What you did
(30w)(1yr) + (60w)(1yr) = whatever


What you should have done assuming your assumption that it takes 3x the power to cool it for half a year is true (which as I've said, it isn't)

(30w)(1yr) + (90w)(.5yr) = whatever


Which it doesn't matter how you did it anyway, since as I said, it it WAY wrong

I am pretty sure over 100% efficiency violates some of the most fundamental laws of physics. Such as conservation of energy.

Not in this case, you're misapplying the laws of thermodynamics.

The "no greater than 100% eff" means that, say, you cannot get 50j of work out of 25j of energy, which is completely true and absolute


But that's not what ACs do. All they do is move the heat from inside and outside, which is pretty simple to do and extremely efficient.


If you task an AC with "cooling" (moving) 100w of heat, it may only need 50w of energy to do so. It's not countering the 100w, or negating it in any way, just moving it


See now? If AC was anywhere near as inefficient as you are thinking it is we'd all live way up north and not even have AC cause it would be WAY prohibitively expensive

 

[taltamir]

What you should have done assuming your assumption that it takes 3x the power to cool it for half a year is true (which as I've said, it isn't)

(30w)(1yr) + (90w)(.5yr) = whatever

You are missing the fact that you save on heating in the winter, hence:
(30w)(1yr) + (90w)(.5yr) - (30w)(.5yr) = whatever

anyways, back to topic... I looked up some real world values for AC efficiency and done the math:

1 BTU = 1.06 KJ

Wh * 3600 s/h = 3600Ws = 3600J

SEER is measured in BTW/Wh
or 1.06 KJ (removed)/ 3.6KJ (spent) = 1.06 (removed)/ 3.6 (spent)

Average SEER is 10... this means 2.9444444444444444444444444444444, or approximately 3 removed/spent value...
Whomever wrote the article that claimed it takes 3x energy to remove x energy got it backwards! its the opposite... You remove 3 units of energy for every 1 unit spent.

let me adjust my calculations then, before it was 2.5x for someone who cools half the year and heats half a year. and 2.7x for someone who cools for 2/3 of the year and heats for 1/3.
lets calculate correct values:

summer: x watt GPU + x/3 watts by AC, winter x watts by GPU - x watt heating.
yearly operating cost is thus 2x/3 = 0.67x
if you cool 2/3 of the year and heat for 1/3 of the year it is 8x/9 = 0.89x

Either way... the advantages of lower heating cost in the winter are greater then the extra cost of cooling in the summer...

meaning that if your total power consumption cost of the electricity for the device alone is 30$ a year, and you are on a 6 months cooling 6 months heating cycle, savings on heating will be greater then expenses on cooling and result in a total expense of 30$/ear * 2/3 = 20$/year
Since I am on a 8 month cool 4 month heat cycle it would be 26.67$/year

 

[yh125d]

This needs clarifying... AC efficiency is not measured in percents.
A 100% efficient AC unit will consume no energy at all and move heat against its heat gradients.
A greater than 100% efficient AC unit will PRODUCE energy while moving heat against its heat gradient...

both are physically impossible.

Watt is a measurement of power
Joule and BTU are a measurement of energy
AC efficiency is measured as energy it moves / (power * time)
Or (Energy/time)/power

Example, (BTU/h)/Watts, which is known as "Seasonal energy efficiency ratio (SEER)"

This is not a percentage... mmm, actually I got some interesting numbers, I can use those to calculate whether or not the 3x figure is correct or not, and if not, what is a correct figure. BRB

AC eff is not typically viewed as a % yes but it can be shown as one pretty simply. It would be power drawn by unit/heat dispelled by unit


Example: A 1000BTU window unit usually consumes about 1-1.1kw. By your 3x figure, that means it would only be sufficient to cool 350w of heat. Do you really think a large window unit like that is only sufficient to cool, say, 2 5870s?

D:

 

[yh125d]

You are missing the fact that you save on heating in the winter, hence:
(30w)(1yr) + (90w)(.5yr) - (30w)(.5yr) = whatever

anyways, back to topic... I looked up some real world values and:

1 BTU = 1.06 KJ

Wh * 3600 s/h = 3600Ws = 3600J

SEER is measured in BTW/Wh
or 1.06 KJ (removed)/ 3.6KJ (spent) = 1.06 (removed)/ 3.6 (spent)

Average SEER is 10... this means 2.9444444444444444444444444444444, or approximately 3 removed/spent value...
Whomever wrote the article that claimed it takes 3x energy to remove x energy got it backwards! its the opposite... You remove 3 units of energy for every 1 unit spent.

Believe me now?

A 1kw baseboard heater is a pretty small heater. But a 1kw AC cools a house a hell of a lot more than a tiny 1kw heater heats it, and the heater's supposed to damn near 100% eff!

 

[taltamir]

Believe me now?

A 1kw baseboard heater is a pretty small heater. But a 1kw AC cools a house a hell of a lot more than a tiny 1kw heater heats it, and the heater's supposed to damn near 100% eff!

I don't "believe" you... I did the math to myself and found out that your hunch was right and the article I read was wrong.
you claimed a sanity check failure though (not in those words though ), that is, that the figures were impossible ridiculously high. The figure was off by a factor of 9 (x/3 vs 3x), which is a low enough for me to not intuitively see it.

 

[yh125d]

I don't "believe" you... I did the math to myself and found out that your hunch was right and the article I read was wrong.
you claimed a sanity check failure though (not in those words though ), that is, that the figures were impossible ridiculously high. The figure was off by a factor of 9 (x/3 vs 3x), which is a low enough for me to not intuitively see it.

It wasn't a hunch, I knew that it wasn't so.


Don't believe everything you read online, you gotta keep your common sense and a good bullshit detector.

 

[taltamir]

It wasn't a hunch, I knew that it wasn't so.

Don't believe everything you read online, you gotta keep your common sense and a good bullshit detector.

I am well aware of that.

 

[ArchAngel777]

I don't "believe" you... I did the math to myself and found out that your hunch was right and the article I read was wrong.
you claimed a sanity check failure though (not in those words though ), that is, that the figures were impossible ridiculously high. The figure was off by a factor of 9 (x/3 vs 3x), which is a low enough for me to not intuitively see it.

Can I start calling you Data from Star Trek?

 

[taltamir]

Can I start calling you Data from Star Trek?

I would be honored!

@yh125d:
PS. the reason I called it a hunch is because you did not provide a value.. you said "3x seems to high" but could not say what the actual correct value. I ended up calculating said value to be X/3

 

[yh125d]

I would be honored!

@yh125d:
PS. the reason I called it a hunch is because you did not provide a value.. you said "3x seems to high" but could not say what the actual correct value. I ended up calculating said value to be X/3

That's because it varies a lot with the many different kinds of AC. If you pushed me for a number I would have said about 200% "efficiency"

 

[taltamir]

That's because it varies a lot with the many different kinds of AC. If you pushed me for a number I would have said about 200% "efficiency"

its a 3:1 ratio, not a percent ratio... to give it in percent ratio is misleading and incorrect...

An AC would have a % efficiency actually, for its mechanical internals (which cannot be 100% or higher)...
A 50% efficient AC cooling an empty box would need to pull 2 KJ from the wall, 1KJ would dissipate as heat (outside, where the AC is), the other 1KJ would be used to move 3KJ from inside the box to the outside, in the process of doing work it would be converted to heat. End result is that the box is 3KJ cooler, the outside 5KJ hotter, and that extra 2KJ on the outside came from you buying them...

Ofcourse, said hypothetical AC unit has a worse SEER value then 10 (the 3:1 ratio), because SEER value is a combination of both the efficiency of moving energy from point A to point B, as well as the efficiency of the hardware inside it (mostly just the compressor mostly). That hypothetical example was a SEER value of 5.

SEER btw should be measured under specific conditions (certain temperature outside, certain temperature inside, certain volume of air inside, certain air pressure, etc) for the value to be consistent.

Anyways, back to what you said...
please don't call a 3:1 ratio 200% efficiency, its not that kind of efficiency.

Also, 3:1 would be 300% not 200% because it is ratio.
if we were to compare two devices, one of which has 3x the performance of the other, then you would say it is 200% faster or you would say it is 300% the speed of the other (both mean the same thing).
In this case it is the type of ratio that would be counted as 300%...

 

[yh125d]

its a 3:1 ratio, not a percent ratio... to give it in percent ratio is misleading and incorrect...

An AC would have a % efficiency actually, for its mechanical internals (which cannot be 100% or higher)...
A 50% efficient AC cooling an empty box would need to pull 2 KJ from the wall, 1KJ would dissipate as heat (outside, where the AC is), the other 1KJ would be used to move 3KJ from inside the box to the outside, in the process of doing work it would be converted to heat. End result is that the box is 3KJ cooler, the outside 5KJ hotter, and that extra 2KJ on the outside came from you buying them...

Ofcourse, said hypothetical AC unit has a worse SEER value then 10 (the 3:1 ratio), because SEER value is a combination of both the efficiency of moving energy from point A to point B, as well as the efficiency of the hardware inside it (mostly just the compressor mostly). That hypothetical example was a SEER value of 5.

SEER btw should be measured under specific conditions (certain temperature outside, certain temperature inside, certain volume of air inside, certain air pressure, etc) for the value to be consistent.

Anyways, back to what you said...
please don't call a 3:1 ratio 200% efficiency, its not that kind of efficiency.

Also, 3:1 would be 300% not 200% because it is ratio.
if we were to compare two devices, one of which has 3x the performance of the other, then you would say it is 200% faster or you would say it is 300% the speed of the other (both mean the same thing).
In this case it is the type of ratio that would be counted as 300%...

No I'm saying I would have guesstimated 200% efficiency, meaning 2:1 ratio

 

[taltamir]

No I'm saying I would have guesstimated 200% efficiency, meaning 2:1 ratio

ah ok... i get it.

 

[yh125d]

Yeah, 200% better implies a 3:1 ratio, but 200% efficiency only implies a 2:1 (not to be mistaken for "200% more efficient"

 

[Ben90]

Lol @ thread direction.