Why do so many computer cases have solid panels in front of the fans and only a small vent on the sides for the intake air?

[Tristerin]

15 minutes ago, HairlessMonkeyBoy said:

@Tristerin

 

How about this:

 

Say its cold in your house/bedroom. Really cold. And for some reason you can't turn the heat on. The only thing you have to heat your room is your PC. So you turn it on and load up the GPU and CPU with F@H or something so you don't feel so bad for wasting the power. How do you set the fans to best heat the room?

The same as I would to keep the components as cool as possible - full blast.  But I wouldn't do that in your theoretical situation (as I wouldn't care about the room heat overall, just myself) so I would potentially not run the fans at all but the lowest speed so that the air exiting is as hot as possible.  If the room has no ducted air to keep it as cold as your hypothesis you are wanting to "test" then eventually, many days from the start of this test, the temperature will rise.

 

Once again, I agree, and understand how it works.  But this test, isn't real life.  Or how any of us operate our homes, server rooms, etc.  We duct cold air in, and remove the hot air out as quickly as possible.  And how do we keep the ambient temps to the lowest level possible in order to have to duct in the least amount of cold air when running hot components?  Keep them as cool as possible.

[Hairless Monkey Boy]

22 minutes ago, Tristerin said:

The same as I would to keep the components as cool as possible - full blast.

This is correct, but your reasoning is wrong. If the fans themselves did not consume any power and we did not care about keeping our components cool, then the answer would be that it does not matter. The system is using and therefore dumping the same amount of energy into the room regardless of the fan speed, so the room heats up at exactly the same rate, regardless. However, since the fans do consume power, having them maxed out adds additional energy to the room, thus heating it slightly more quickly.

 

25 minutes ago, Tristerin said:

And how do we keep the ambient temps to the lowest level possible in order to have to duct in the least amount of cold air when running hot components?  Keep them as cool as possible.

This is wear you are tripping up I think. The smaller amount of hotter air and the larger amount of cooler air both contain the same total amount of energy, and therefore heat the ambient air in the room at the same rate and by the same amount. The presents of airflow or lack thereof in the room is a completely independent variable. If you take any of my "Hypothetical" situations and add an equal amount of room level airflow, the results will be the same. In the first example, instead of both rooms rising by 10C each, if you add some room level airflow, perhaps both rooms might rise by 5C each instead, still equal. In the second example, if you add room level airflow to your cold bedroom, the fans set high or low will still not matter, the room will be heated an equal amount more slowly. 

[Tristerin]

10 minutes ago, HairlessMonkeyBoy said:

This is correct, but your reasoning is wrong. If the fans themselves did not consume any power and we did not care about keeping our components cool, then the answer would be that it does not matter. The system is using and therefore dumping the same amount of energy into the room regardless of the fan speed, so the room heats up at exactly the same rate, regardless. However, since the fans do consume power, having them maxed out adds additional energy to the room, thus heating it slightly more quickly.

 

This is wear you are tripping up I think. The smaller amount of hotter air and the larger amount of cooler air both contain the same total amount of energy, and therefore heat the ambient air in the room at the same rate and by the same amount. The presents of airflow or lack thereof in the room is a completely independent variable. If you take any of my "Hypothetical" situations and add an equal amount of room level airflow, the results will be the same. In the first example, instead of both rooms rising by 10C each, if you add some room level airflow, perhaps both rooms might rise by 5C each instead, still equal. In the second example, if you add room level airflow to your cold bedroom, the fans set high or low will still not matter, the room will be heated an equal amount more slowly. 

Sigh

 

I herp, derp understand the science.  I herp, derp get what you are repeating.  I herp, derp agree with what you are saying in your uncontrolled hypothetical situations to prove a point behind already proven points in science.  There is no need to prove this.  How many times, must I agree with you.  

 

But, considering this is real life, and not your hypothetical situations that not even .1% of PC user base are encountering - there is a reason for high airflow cases, and Im done repeating myself the why.  If there wasnt a short term thermal benefit...gasp, it wouldnt matter (HAF cases...but there is a reason they exist)

 

So please, tell me why high air flow cases in the real world are the same as a enclosed box with the same PC inside it.

[Hairless Monkey Boy]

8 minutes ago, Tristerin said:

So please, tell me why high air flow cases in the real world are the same as a enclosed box with the same PC inside it.

They aren't the same. HAF cases are better. They keep the components inside cooler.

[Tristerin]

1 minute ago, HairlessMonkeyBoy said:

They aren't the same. HAF cases are better. They keep the components inside cooler.

And why would one want to keep their components cooler inside the case?  They dont operate any differently as long as within thermal operating temperature thresholds.

 

That was the question I answered btw, Im keen on hearing your response.

 

 

[Hairless Monkey Boy]

Just now, Tristerin said:

They dont operate any differently

Yes they do operate differently. GPUs and CPUs clock higher at lower temperatures, and manual overclocks can be set higher at lower temperatures. Not to mention the benefits to longevity with running components cooler.

[Tristerin]

Just now, HairlessMonkeyBoy said:

Yes they do operate differently. GPUs and CPUs clock higher at lower temperatures, and manual overclocks can be set higher at lower temperatures. Not to mention the benefits to longevity with running components cooler.

Not what I asked, and as long as within thermal specifications they will behave as advertised (1s and 0s).  Not to add more uncontrolled "controls" to my question, lets keep it simple and verbatim - Ive been answering you each time.

 

4 minutes ago, Tristerin said:

And why would one want to keep their components cooler inside the case?  They dont operate any differently as long as within thermal operating temperature thresholds.

 

That was the question I answered btw, Im keen on hearing your response.

 

 

 

[Tristerin]

3 minutes ago, HairlessMonkeyBoy said:

lower temperatures.

Actually, I see you did answer.  Boom.

 

Thats the reason for airflow cases, as I stated.  And now the why - because it takes ALOT longer to heat a room up with 48c components than with 70c components.  

 

[Hairless Monkey Boy]

1 minute ago, Tristerin said:

because it takes ALOT longer to heat a room up with 48c components than with 70c components. 

Yeah, but no it doesn't. Given the same quantity of air, yes. But we are not talking about the same quantity of air. We are talking about proportional amounts of air at proportionally different temperatures, each containing the same amount of energy.

Spoiler

 

You have 2 pots of 1L of water at a temperature of 300K.

 

Into one of the pots, you pour 1L of water which is at 320K. The resulting mixture is measured to be (300K*1+320*1)/2 = 310K.

 

Into the other pot, you pour 2L of water which is at 315K. The resulting mixture is measured to be (300K*1+315K*2)/3 = 310K.

 

Spoiler

Say you have two  space heaters that operates at 1KW, or 2KW, and have fan speeds of 50 CFM or 100 CFM.

 

You set each heater up in separate but equivalent rooms. Both rooms are at 20C.

 

The first heater is setup at 1KW and 50 CFM. When measured, the temperature of the air exiting the heater is 30C. You leave this heater running in the room for one hour. When you measure the temperature of the air in the room, it is now at 30C. You also measure the temperature of the air that is now exiting the heater, and it is now at 40C.

 

The second heater is setup at 2KW and 100 CFM. When measured, the temperature of the air exiting the heater is again 30C. You leave this heater running in the room for one hour. When you measure the temperature of the air in the room, it is now at 40C. You also measure the temperature of the air that is now exiting the heater, and it is now at 50C.

Do those make sense to you?

[Tristerin]

7 minutes ago, HairlessMonkeyBoy said:

Yeah, but no it doesn't. Given the same quantity of air, yes. But we are not talking about the same quantity of air. We are talking about proportional amounts of air at proportionally different temperatures, each containing the same amount of energy.

  Reveal hidden contents

 

You have 2 pots of 1L of water at a temperature of 300K.

 

Into one of the pots, you pour 1L of water which is at 320K. The resulting mixture is measured to be (300K*1+320*1)/2 = 310K.

 

Into the other pot, you pour 2L of water which is at 315K. The resulting mixture is measured to be (300K*1+315K*2)/3 = 310K.

 

  Reveal hidden contents

Say you have two  space heaters that operates at 1KW, or 2KW, and have fan speeds of 50 CFM or 100 CFM.

 

You set each heater up in separate but equivalent rooms. Both rooms are at 20C.

 

The first heater is setup at 1KW and 50 CFM. When measured, the temperature of the air exiting the heater is 30C. You leave this heater running in the room for one hour. When you measure the temperature of the air in the room, it is now at 30C. You also measure the temperature of the air that is now exiting the heater, and it is now at 40C.

 

The second heater is setup at 2KW and 100 CFM. When measured, the temperature of the air exiting the heater is again 30C. You leave this heater running in the room for one hour. When you measure the temperature of the air in the room, it is now at 40C. You also measure the temperature of the air that is now exiting the heater, and it is now at 50C.

Do those make sense to you?

Where in any of those remarks, did they introduce a far denser, colder unit of measure (temperature controlled room, not a sealed box or room) in a far vaster quantity (like, my house which is temperature controlled)?  I was away for a bit and decided to approach this more open minded.  But neither of those are present in the equation, which...impact the equation when it comes to consumer PC folks.  I mean, my room has 3 cold forced air vents keeping it 70c in here.  And hot air is escaping at all times at the door frames into the other room too.  Or does everyone live in a sealed box?

 

 

 

[Hairless Monkey Boy]

3 minutes ago, Tristerin said:

I was away for a bit and decided to approach this more open minded.

That's good. This is all in good spirits on this side. Really just trying to help you understand.

4 minutes ago, Tristerin said:

like, my house which is temperature controlled

I have already addressed this here:

1 hour ago, HairlessMonkeyBoy said:

If you take any of my "Hypothetical" situations and add an equal amount of room level airflow, the results will be the same. In the first example, instead of both rooms rising by 10C each, if you add some room level airflow, perhaps both rooms might rise by 5C each instead, still equal. In the second example, if you add room level airflow to your cold bedroom, the fans set high or low will still not matter, the room will be heated an equal amount more slowly.

But to elaborate further. The PC is dumping an identical amount of energy into the room regardless of the airflow and regardless of the resulting temperatures of the components or the exhaust air. The only variables that matter for the temperature rise of the room, are how much energy is going in, and how much is going out. If you have a net inflow of energy, the temperature will rise. A net outflow, and the temperature will fall. Equal, and the temperature will remain constant. Your PC, regardless of the speed of the fans and regardless of the temperature of the exhaust air, will be dumping the same 500W of energy into the room, and your home cooling will have to remove the same 500W in order to keep the temperature of the room constant. Nowhere in that equation does the temperature of the exhaust air factor in.

 

Listen.

 

I completely understand how this works, and I know that I am right.

 

And you completely understand how this works, and you know that you are right.

 

The problem is that one of us has to be wrong.

 

Spoiler

And it ain't me, friend. 

I like explaining this kind of stuff, and I've had some fun here, but I think we are at an impasse. So if I still haven't convinced you then I'm just going to carry on my marry way. 

 

[Tristerin]

35 minutes ago, HairlessMonkeyBoy said:

2 hours ago, HairlessMonkeyBoy said:

In the second example, if you add room level airflow to your cold bedroom, the fans set high or low will still not matter, the room will be heated an equal amount more slowly. 

 

 

 

This is where I didnt read - absolutely see your point and will dismiss my "time" variable.  I mean that as in, my use case my central air doesnt have an issue maintaining the room temperature - because I dont allow it to balance. "Time" for me wasnt long enough to matter vs the cooling effectiveness available and I used that as my baseline sample.

 

 

 

[LloydLynx]

Coming from someone who cut a hole in the front of their dell, I think it's pretty dumb to make the front blank and sacrifice air flow. Static pressure fans would probably improve air flow in the front of one of those cases.