Does a pc consuming 500 watts from wall, heat a room similar to 500 watts hair dryer?

[Brooksie359]

1 hour ago, Agall said:

Is there something wrong with answering both? I see no problem with answering the question and then going into detail on why I believe that answer is correct. It subjects you to more scrutiny since an answer could be correct for the wrong reasons, but in my opinion, that's the goal of doing so, for the sake of truth and accuracy. In the end, everyone wins.

I mean more information isn't always better. If someone gives a super complicated answer to something that can be answered in a much simpler way it starts to be confusing especially when trying to figure out what information is relevant or not. One of the most difficult physics questions are the ones where the question provides more information than is necessary to solve the question because then people assume that you were supposed to use that info to help solve the problem when it wasn't relevant all along. 

[Agall]

4 minutes ago, Brooksie359 said:

I mean more information isn't always better. If someone gives a super complicated answer to something that can be answered in a much simpler way it starts to be confusing especially when trying to figure out what information is relevant or not. One of the most difficult physics questions are the ones where the question provides more information than is necessary to solve the question because then people assume that you were supposed to use that info to help solve the problem when it wasn't relevant all along. 

That why you become proficient in the art of answering a question in multiple ways with multiple levels of complexity. Some people require certain bits of information to understand a topic, where more relevant data is better than less, since person X might understand a topic with information 1,2,4,5,6,9 and another person Y might understand with information 1,2,6,7,9,10. Excluding information 6-10 might allow person X to understand the majority of the topic but exclude person Y.

 

I've had to teach plenty of people with various levels of intelligence absurdly complex topics over the years, to the extent of nuclear engineering and physics, so I understand your concerns. I believe my first post gave a simple enough answer to the OP, but feel free to critique it if you'd like:

 

Most of the energy into a computer is converted into heat waste but not all of it. In both devices, some of that energy is converted into mechanical energy to move the air as well.

 

If you eliminate a lot of the variables, example being how most PCs disperse heat more homogenously around them versus the beam design of a hair dryer, then practically the answer is yes.

 

If we consider other variables, that gets into the discussion of heat flux, which its heat transfer per second per square area, where a hair dryer is more likely to have a higher heat flux than a computer based on its design. The volume of the affected space being proportional to how much a given amount of energy raises the temperature of the space. Temperature being the average random molecular kinetic energy of a substance.

[Kilrah]

5 minutes ago, Agall said:

Most of the energy into a computer is converted into heat waste but not all of it. In both devices, some of that energy is converted into mechanical energy to move the air as well.

That air movement eventually ends up as heat in the room as well, so considering it separately is incorrect in the context of the question.

 

The rest is irrelevant unless brought up, and it wasn't so isn't helpful. OP was pretty clearly after a yes/no answer to the most basic scenario you could think of.

 

5 minutes ago, Agall said:

That why you become proficient in the art of answering a question in multiple ways with multiple levels of complexity.

The opposite of that was shown here...

[jaslion]

4 hours ago, Applefreak said:

That being said, you can't rely on such a solution to properly warm up a room in winter time alone. Same goes for a 500W hair dryer or space heater, those are not powerful as well.

Tell that to my insulation :p.

It will heavily depend on the house and stuff but if you have GOOD insulation 500w can keep a room warm

[Agall]

13 minutes ago, Kilrah said:

That air movement eventually ends up as heat in the room as well, so considering it separately is incorrect in the context of the question.

 

The rest is irrelevant unless brought up, and it wasn't so isn't helpful. OP was pretty clearly after a yes/no answer to the most basic scenario you could think of.

 

The opposite of that was shown here...

Yes, eventually that air current created will disperse its kinetic energy to the surrounding air in the space, assuming its not displaced outside of the space we're using as a frame of reference which would therefore transport it to another space, something forced air can do far easier than thermal expansion in this context.

 

The rest is simply your opinion since OP has yet to respond or mark a solution. I for one decline to make that assumption and would rather provide them with what I believe to be the best answer to the question, otherwise I wouldn't bother elaborating. You can feel free to disagree with me on my opinion, unless your intention is to refute something I'm saying on a factual basis.

 

I will disagree with the notion that explaining thermodynamics in response to a question about thermodynamics isn't relevant. 

[Brooksie359]

14 minutes ago, Agall said:

That why you become proficient in the art of answering a question in multiple ways with multiple levels of complexity. Some people require certain bits of information to understand a topic, where more relevant data is better than less, since person X might understand a topic with information 1,2,4,5,6,9 and another person Y might understand with information 1,2,6,7,9,10. Excluding information 6-10 might allow person X to understand the majority of the topic but exclude person Y.

 

I've had to teach plenty of people with various levels of intelligence absurdly complex topics over the years, to the extent of nuclear engineering and physics, so I understand your concerns. I believe my first post gave a simple enough answer to the OP, but feel free to critique it if you'd like:

 

Most of the energy into a computer is converted into heat waste but not all of it. In both devices, some of that energy is converted into mechanical energy to move the air as well.

 

If you eliminate a lot of the variables, example being how most PCs disperse heat more homogenously around them versus the beam design of a hair dryer, then practically the answer is yes.

 

If we consider other variables, that gets into the discussion of heat flux, which its heat transfer per second per square area, where a hair dryer is more likely to have a higher heat flux than a computer based on its design. The volume of the affected space being proportional to how much a given amount of energy raises the temperature of the space. Temperature being the average random molecular kinetic energy of a substance.

The last paragraph doesn't explain anything though. That is more confusing than helpful especially because it doesn't explain much especially because 500w of heat is still 500w of heat and the heat flux doesn't effect the fact that 500w of heat will be added to the room and the temperature increase in the room will still be basically the same over the long term. 

[Brooksie359]

7 minutes ago, jaslion said:

Tell that to my insulation :p.

It will heavily depend on the house and stuff but if you have GOOD insulation 500w can keep a room warm

Honestly the biggest thing that screws your insulation isn't actually your walls its the windows. Ideally we wouldn't have so many windows and you could drastically increase the heating and cooling efficiency of houses but obviously building codes need a certain amount of windows for obviously reasons. 

[Agall]

40 minutes ago, Brooksie359 said:

Honestly the biggest thing that screws your insulation isn't actually your walls its the windows. Ideally we wouldn't have so many windows and you could drastically increase the heating and cooling efficiency of houses but obviously building codes need a certain amount of windows for obviously reasons. 

I'm still living that single pane life in my house  

 

43 minutes ago, Brooksie359 said:

The last paragraph doesn't explain anything though. That is more confusing than helpful especially because it doesn't explain much especially because 500w of heat is still 500w of heat and the heat flux doesn't effect the fact that 500w of heat will be added to the room and the temperature increase in the room will still be basically the same over the long term. 

Where heat flux applies is that ~500W of thermal output is being exhausted from a ~3" diameter port, versus a 500W gaming PC that likely has 3-4 exhaust paths with each a higher amount of surface area and direction of air flow which may be 5x the surface area in total. It's no different than how a computer in the corner will disproportionally heat that corner relative to the opposite corner of the room, like how a hair dryer will disproportionately heat the object its exhaust is pointed at compared to objects on the side of its intake. Even in a generalized answer, that will affect how that heat propagates throughout the space and therefore its average temperature. 

 

500W through a 3" diameter hole at a given mass flow rate and temperature will disproportionately create a hotspot compared to 500W across 4x 120mm fans at a given speed and temperature. Any heat source will create hot spots, the more homogenous it spreads that heat, the better it will be at changing the average temperature of the space. That doesn't mean there's less thermal energy entering the room, but it does specifically affect how well it will "heat a room" as the OP asks, since there's multiple heatsinks in the normal environment of a room that can drastically change how well those hot spots propagate. Why I make caveats is because simply answering Yes or No isn't properly answering the question, since there's variables not established or eliminated.

 

Where we're likely disagreeing on is what variables we assume to be established or eliminated, which is why I specify. Its the major reason why I generalize and say Yes, to answer the potential root question of "does 500W of thermal energy = 500W of thermal energy" while following up with more information by discussing heat flux, that "100W/m2 =/= 200W/m2, even if both are a 500W heat source" (numbers made up for simplicity, I'd rather not have to calculate the heat flux of a hair dryer and computer but its obviously different).

 

"Does a pc consuming 500 watts from wall, heat a room similar to 500 watts hair dryer?"

[RevGAM]

Speaking as a former educator, I agree that a simple yes or no is not usually sufficient. Did anyone in this thread answer the question with a yes or no? If not, then that just goes to show that, consciously or not, everyone else also recognizes this fact.

 

Sure, some people will always and only want a yes or no, but they may be motivated by impatience, a need for a quick answer or other reasons. Also, sometimes a closed-ended questions cannot or should not be answered with just yes or no. Often, as I saw as a teacher and I see on forums like this where people come from all over the world with varying levels of ability in English, questions can be poorly phrased such that a simple answer isn't actually possible without, at minimum, a full sentence to dispel the confusion that a yes or no would cause. Additionally, when I lived in Indonesia, I often ran into the problem of people answering multiple choice questions verbally with a single word answer that didn't choose anything (although the speaker knew what they meant).

 

Speaking on a personal level, I like more info rather than less because I am a life-long learner and, even though some of you can go way over my head on things like physics, maths, etc., I'd rather the opportunity to try to understand it than not learn. That said, plenty of people grew up in horrible educational systems and hate learning because of it.

 

Did the OP necessarily want as much info as Agall (and others) gave? Only the OP can answer that.

[cmndr]

For all intents and purposes a running a 500W computer for is equivalent to a 500W space heater or hair dryer in terms of how much it'll heat up a room, 1 hour into the future. 

The only real difference would be whatever energy ends up as light, which could then potentially bounce out of the room and the rate at which it'll warm up the room the computer will radiate it more slowly, but it WILL eventually get out there. 
Probably the big "exception" to it feeling the same would be a system with a huge water cooling reservoir. The reservoir would take a VERY long time to dispel the heat into the room. It also raises the overall heat capacity of the room since water can hold thousands of times more heat than air. 

Air movement becomes heat eventually. Light becomes heat eventually (assuming it doesn't escape). Most of the things people obsess over are second order effects with negligible impact. Pretty much the only alternate variable would be the heat capacity of the computer/its cooler and all that does is slow down the inevitable. 

[RevGAM]

10 hours ago, cmndr said:

For all intents and purposes a running a 500W computer for is equivalent to a 500W space heater or hair dryer in terms of how much it'll heat up a room, 1 hour into the future. 

The only real difference would be whatever energy ends up as light, which could then potentially bounce out of the room and the rate at which it'll warm up the room the computer will radiate it more slowly, but it WILL eventually get out there. 
Probably the big "exception" to it feeling the same would be a system with a huge water cooling reservoir. The reservoir would take a VERY long time to dispel the heat into the room. It also raises the overall heat capacity of the room since water can hold thousands of times more heat than air. 

Air movement becomes heat eventually. Light becomes heat eventually (assuming it doesn't escape). Most of the things people obsess over are second order effects with negligible impact. Pretty much the only alternate variable would be the heat capacity of the computer/its cooler and all that does is slow down the inevitable. 

I think you hit on the crux of the difference: a 500W hair dryer immediately starts pumping all of its heat into the air, whereas a 500W computer does not and will take longer to release all that power as heat.  Very concise.