Computer heater

[Gearshredder]

I usually run my computer all the time and it acts as a pretty good heater when im not using it :) Is it better to turn it off and run the central air or to keep it runnin? It is in my bedroom so i go and close the door and it gets up to 75+ degrees F in a few hours from 60, plus it being in the basement and 40 degrees outside. What do you guys think?

[trebuchet03]

It's probably cheaper to use your computer -- as you're only heating one room rather than running your central system ;)

[Gearshredder]

cept maybe when i open the door.. and all the heat dissipates lol
well does a computer acctually put out 100% heat of the power it uses to process? lol

[88HF]

Aye? The computer doesn't "intend" to put off any heat, its a consequence of inefficiency.

[Erdrick]

I say just do the math. How much does your computer use to run? How much would you be paying to use your central heating. The central air could be better if it is more efficient. As 88HF says, the heat put off by a computer is just it being inefficient. From the power supply to the RAM to the CPU, they all do a somewhat bad job of using the power to crunch the numbers.

If you are using your computer to upload torrents or something like that though... then the story could change a bit. I keep mine running most of the time, but mine only uses 25 watts when the screen is shut. I definitely don't get any heat from it.

[rh77]

If you're looking to generate excess heat and benefit Gene Research at the same time, you could run the Stanford Gene Folding Project. (http://folding.stanford.edu/)

LSS, it's a distributed computing effort (like SETI @ home), whereby you can set the program to use any percentage of the processor's availability, which for me is always 100%. It's a passive program, meaning it will give priority to other processes first, so you don't generally perceive a drop in performance. I've been running this on laptops and desktops for a few years now without a problem. Desktops seem to handle the heat better, of course.

RH77

[trebuchet03]

well does a computer actually put out 100% heat of the power it uses to process? lol

Not 100% - but a percentage of it ;) You just have to look at how much energy is consumed by your computer -- and how much is consumed by central heating ;)

Efficiency doesn't matter too much here - it's total consumption. Think of an 80% efficient engine that consumes 5 gallons of fuel per hour. Now compare that two a smaller engine that's 40% efficient, but only consumes 2 gallons of fuel per hour :p

[psyshack]

If you're looking to generate excess heat and benefit Gene Research at the same time, you could run the Stanford Gene Folding Project. (http://folding.stanford.edu/)

LSS, it's a distributed computing effort (like SETI @ home), whereby you can set the program to use any percentage of the processor's availability, which for me is always 100%. It's a passive program, meaning it will give priority to other processes first, so you don't generally perceive a drop in performance. I've been running this on laptops and desktops for a few years now without a problem. Desktops seem to handle the heat better, of course.

RH77

I Fold!!!! Puter room stays very warm indeed. :)

Q6600 @ 3.6 ghz
E6600 @ 3.36 ghz.
E6400 @ 3.28 ghz
XPM @ 2.4 ghz
Lappy @ 1.7 ghz

All run 24/7, 100% cpu load. Four air cooled. One water cooled.

Then through in the fish tanks I have running in the room. It gets very warm. :)

[Gearshredder]

If you are using your computer to upload torrents or something like that though...
Srry, torrents arent safe nemore... :(

but yes.. for all that time my computer is on.. i prob be doin that.. and warm up my room faster :)

[rh77]

I Fold!!!! Puter room stays very warm indeed. :)

Q6600 @ 3.6 ghz
E6600 @ 3.36 ghz.
E6400 @ 3.28 ghz
XPM @ 2.4 ghz
Lappy @ 1.7 ghz

All run 24/7, 100% cpu load. Four air cooled. One water cooled.

Then through in the fish tanks I have running in the room. It gets very warm. :)

I have 3 PCs in the basement -- old recycled models for folding:

2 @ 1 GHz
1 P-III @ 450 MHz
(stays cool downstairs for the "antiques")
4 Laptops in the house:
One -- had to give up folding (backup in case one goes down, for the road) ~1.4 Celeron :thumbdown:
- The Wife's Dual-Core Dell with T7200 @ 2.00 GHz (intermittent folding, powerhouse otherwise).
-"The Highwayman" 1.7GHz (this one is used 99% of personal use, always folding 24/7, 100% unless on batt) -- HP Pav dv1331se -- great screen and DVD replay. it's pretty beat-up from the miles and heat. :o Separate from the folding, it's on it's 4th board, power input and power supply (AC adapter). May be the last HP I buy. It's holding on, tho...
-Dual-Core HP 2.4-ish? for the Work-provided one (can't get folding to work well on the company PC).

It's a weak lineup, but it's better than nothing, right???

I take-in old computers and put them to work.

That's cool (literally) with the water-cooled unit! I put my $$$ into laptops for road power.

I'm torn what to do next month -- company stipend for personal computer use ($1200). A desktop would get lots of power, and I could built it myself. Problem is, the lifestyle around the house is laptops on Wireless (printing, backup, everything). I like to play Flight-Sim, and the 1.7 can't handle FSX, so I'm running the old 2004. I'm still looking for a way to do a dumb terminal from the laptop (screen, keyboard, touchpad) and hide a box behind the couch or something. But, that gets me nothing on the road -- but laptop power is 'spensive. Meh, we'll see.

RH77

[omgwtfbyobbq]

If yer leaving it on crunching distributed stuff, maybe climateprediction.net is the most suitable, since the computer is likely powered by some form of FF electricity generation.

[SVOboy]

Get a macbook, :p

I need to close my laptop to move around between classes and such, can folding accommodate being stopped and restarted all the time?

[DracoFelis]

well does a computer acctually put out 100% heat of the power it uses to process?
My understanding is that virtually all electric devices (not just computers, virtually ALL of them) have so close to 100% of their power ultimately end up as "waste heat", that it's not worth worrying about the difference!

i.e. use a 100 watt bulb, and you not only get light but also essentially 100 watts of heat as well. Replace a 100 watt light with a 17 watt compact florescent, and you have also lowered the heat by 83 watts of power savings. Etc.

Now, in the summer this effectively works AGAINST you, as any power you use in the house (even fans to move the air around) ultimately is extra heat you are fighting against for cooling! But in the winter, this can actually work in your favor, because the "waste heat" will actually heat things up pretty much as effectively as an electric "space heater" would. i.e. If you would otherwise have to run a space heater at 700 watts of power (to heat up a room you are in), you might as well run "appliances" (TV, lights, computer, etc) that use 700 watts of power between them instead, because it should add about the same level of heat to the room (as the "space heater"), while also giving you other benefits (assuming you actually get some benefit from the electric devices you turned on). So this is one place were "energy efficiency" can actually work against you, as the less efficient the appliances, the more "waste heat" they produce (not just the more electricity they use)!

However, the above analysis assumes that you are comparing running electric devices (including, but far from limited to, computers) against getting your heat from basic electric heating elements (i.e. the laws of physics mean that "waste heat" from electric appliances is almost exactly as effective/efficient as almost all electric "heating elements" on the market).

But when comparing electric to other "heating sources" the results can be different. For example, electric "heat pumps" can often heat up a building at greater than 100% efficiency (i.e. with a heat pump you often get more heat than just converting the electric to heat could give you), because the heat pump (unlike the waste heat, or the electric space heater) isn't actually creating heat from the electricity, but is instead moving heat from the outside (effectively making the outside a little bit colder in the process). Furthermore, there are many other sources of heat (with varying "costs") on the market. And when dealing with those other heating sources, you pretty much have to "run the numbers" to see which is less costly to you. For example, the cost per "therm" for gas is (in many areas) cheaper than the equivalent amount of electric power needed to produce a therm of heat (which is why it is usually "cheaper" to have a gas furnace, than an electric one). And there are even somewhat "free" sources of heat (for example, some solar heating designs).

But when you are just dealing with "electric heat" anyway, its useful to remember that electric devices produce "waste heat" for almost exactly the same amount of input power as an electric heating device (a space heater, an electric stove, etc) would (given the same amount of input electric usage). So in the winter, consider turning on some useful electric appliance BEFORE turning on the electric space heater. It won't save you any power vs the space heater, but you will get two functions (the heat and whatever the device supposedly does) out of the power you do use...

[SVOboy]

A slight correction on the lightbulb thing that I recently heard from an ENVS professor is that incandescent bulbs are 5% efficient at creating light, and 95% at creating heat, whereas flourescents are 20% efficient at creating light and the rest goes to hear (and sometimes a little bit to noise).

*shrug*

[trebuchet03]

My understanding is that virtually all electric devices (not just computers, virtually ALL of them) have so close to 100% of their power ultimately end up as "waste heat", that it's not worth worrying about the difference!

This really isn't the case - especially when you consider how much work is being done. I've been trying to find actual % efficiency numbers for processors - but I think the actual numbers are kept secret. BUT, a great experiment for comparison can be found here:

http://www.tomshardware.com/2007/09/27/what_if_your_cpu_cooler_fails/page15.html

The Final chip completed/survived all benchmarking tests while having a higher wattage rating than another chip that was not able to complete the tests due to heat/temperatures.

All that said -- IF efficiency for all electronics were to be 5% - the size of a power supply to run a 50 watt processor would be 1000 watts. This clearly isn't the case. Power supply efficiency typically runs in excess of 80%

-------
Now, after saying all that.... You can say exactly what you said for ANYTHING given that the device is in a completely closed system. A car, for example, is say 30% efficient (comparing energy in to useful work). BUT, if you look at total waste heat emitted to the universe -- it's 0% efficient as brake heat, heat generated from air friction, etc. all generates heat.

What I'm getting at is - it's easily interpreted that all electronics have very low efficiency as stated (especially when compared to a heater @ 100% efficiency) :p

[88HF]

If you lost 100% the energy from electricity as heat then their would be no visible light from a bulb, no buzzing from a transformer, no signals to be picked up by radios, or sound to be heard from a speaker. Energy is manifested in numerous ways which are not heat.

[DracoFelis]

Now, after saying all that.... You can say exactly what you said for ANYTHING given that the device is in a completely closed system. A car, for example, is say 30% efficient (comparing energy in to useful work). BUT, if you look at total waste heat emitted to the universe -- it's 0% efficient as brake heat, heat generated from air friction, etc. all generates heat.
That's what I was thinking.

For example, you not only have waste heat from the power supply, but you also have waste heat generated from the electronics (CPU, RAM, etc) as a by-product of them doing their job. And when you add up all of those waste heat factors, I was under the impression that the total "waste heat" from the entire electric system was very close to the electric energy put in (with only a very small percentage of the input energy ultimately, after all steps/conversions are accounted for, ending up as anything other than heat energy).

And while I could be wrong, I thought that the with the vast majority of electric devices around the home, the energy (after doing any desired "work") eventually transforms into heat energy. As you pointed out, many times it will take multiple steps (for example, in a computer you move electrons around tiny electric "gates" to do "computations" before a lot of the energy ends up as heat), but ultimately "heat" is usually the form that the energy eventually ends up as. And as we all know, we don't create/destroy energy, we just convert it from one form to another (raising "entropy" in the process).

Of course, another poster on this thread pointed out that there are other possibilities. For example, the energy could be released into the environment as some other form of radiation (i.e. for example, a radio transmitter releases energy as radio waves). And it's also possible to pipe the energy out of the area in some form. But for appliances in an enclosed space, the used energy has to radiate into the area somehow. And I was under the (possibly mistaken) impression that (with the exception of various RF "transmitters") almost all such energy eventually (often after several intermediate steps) becomes thermal radiation (i.e. "waste heat") into the local vicinity.

[Erdrick]

I think we are kind of heading in the wrong direction with this thread. We are talking about maxing out computers' CPU usage and whatnot... kind of the opposite of what this site stands for. Rather than talking about ways to use (or abuse in this case) technologies to make our lives better, why not think of ways to passively let nature help make our existence a more pleasant one? Better sun exposure and things like this are infinitely better than electricity.

[Ryland]

If you are running A/C in the same building as you have a device that gives off heat like your computer does, then you are paying to creat that heat, and you are paying to remove that heat, so you are paying twice for your computer being on, dirrect venting your computer to the outdoors could help if it was cool enough out side, keeping the door of the room closed will help, but unless you have no insulation in the walls, or a window open, it still has an affect on the load of the A/C, a LCD moniter will help cut power used, letting the computer go in to a sleep mode will help, but biggest of all is turning off the computer, I highly recomend getting a watt hour meter that you can plug your computer in to, I suspect that your electrical savings over the course of a year will off set the cost of the meter.

[Gearshredder]

yes.. i definately have to go find one of those meters.. idk why i didnt already..
I tried the folding@home program to max it out and found i wouldnt get a WU done until jan 10 2008.. lol
I will though try to get a more efficient computer cpu such as the core2duo and definitely buying an lcd monitor will help. Except today, those graphic cards are energy hogs.. and produce alot of heat.

[rh77]

yes.. i definately have to go find one of those meters.. idk why i didnt already..
I tried the folding@home program to max it out and found i wouldnt get a WU done until jan 10 2008.. lol
I will though try to get a more efficient computer cpu such as the core2duo and definitely buying an lcd monitor will help. Except today, those graphic cards are energy hogs.. and produce alot of heat.

That estimator deal is WAY off for some reason, until you let it run a few Frames. For me it does the same. Now, I'm halfway through one now, and it estimated to complete Thursday. It's like a trip computer calculating average speed from the start. 15 mph average before you hit the highway, and you'll get to your destination in 24-hours instead of 3.


I need to close my laptop to move around between classes and such, can folding accommodate being stopped and restarted all the time?

Yup -- you can set the checkpoint save from 3- to 30-minutes.

If yer leaving it on crunching distributed stuff, maybe climateprediction.net is the most suitable, since the computer is likely powered by some form of FF electricity generation.

I'll look into it, but I've been crunching for Stanford for a few years now. Medical Research is an important adjunct in my life, but the Environment is also at the top of "my platform".

I think we are kind of heading in the wrong direction with this thread.

My fault -- I inadvertently hijacked the thread with what creates a lot of heat in my computer. When I had a small, well-insulated room in an apartment, the PC (and monitor) would often warm up the place to a comfortable level with the door shut. Conversely, the door needed to open in the summer to improve airflow (and I'm sure the A/C worked harder as a result).

My point is, if your computer is left on all the time, put it to work. The power supply is generally going to create the most heat, second to a CRT monitor. Processor and auxiliary device heat should be negligible (except for some vid-cards).

So, if you look at it this way, the step-down transformer in the power supply is taking 120-volts AC and stepping it down to ~5VDC -- so you have some heat generated in the transfer.

[DracoFelis]

I think we are kind of heading in the wrong direction with this thread.
I disagree. This site is about energy efficiency. And if you find that you "need" some extra heat in the winter, why not get that heat + get something else useful (even if it's just "SETI at home" or some other "common good calculations") done?

i.e. If (and only if) you are going to pay for electric heat anyway (to heat your house), than why not do it with some appliance (that you can get something else "useful" out of), vs just using something that only produces heat? And even if that "something useful" is just helping with some community computation project ("SETI at home", or something similar), you have still gotten something useful "for the community" done along with producing the heat you desire.

Of course, the above assumes that you need to heat your house, and that you were planning to use electricity to do it. If either of those assumptions are incorrect, than the conclusion is also incorrect. For example, if you don't need the heat right now (i.e. it's not winter, or you get enough heat from other sources), than running more appliances just generates more "waste heat" that you don't need. Likewise, even when you do need the heat, you may have a source of heat that is cheaper to use than electric heating (in which case it may be more "efficient" to use that other source of heat). But if you really do need the heat, and your main viable option is simple electric heating, I think it's at least worth considering getting that heat from an appliance that you also get some useful "work" out of...

NOTE:
As another poster (correctly) mentioned, during the warm months you actually get bit twice, when you run an electric appliance. i.e. You pay for the electric to run the appliance, and again for the AC to remove the heat generated by running the appliance.

But the point I was making, is that it works both ways. In the cold months, you actually get a "free bonus" of sorts, in that while you pay the electric to run your appliance, you also get very useful (useful ONLY when it is cold out) "waste heat" off that appliance. This essentially gives you two useful properties (whatever the appliance is designed to do + the "bonus" of the "waste heat") while only paying for the electric (to run the appliance) once (essentially giving you a 2-for-1 with your electric energy dollar).

[trebuchet03]

I disagree. This site is about energy efficiency. And if you find that you "need" some extra heat in the winter, why not get that heat + get something else useful (even if it's just "SETI at home" or some other "common good calculations") done?

I agree :) Otherwise, it would be like using an outdoor BBQ to cook food in 30 degree weather because you have a central heating system :p

[landspeed]

Regarding the computer issue.......

Almost all of the power that goes in is dissipated as heat!.

A little bit goes to the cooling fans. These move the air round, which heats it up. Also, the noise you hear from a computer ends up making things is the room vibrate (how your ears work). This heats the things up!.

Even if the noise didn't make heat, it is probably less than 1 watt of noise on a 300w or so computer!. I would say 99+% ends up as useable heat, which heats your room! It is the same with light bulbs - say 84% of their output is heat, 16% is light - but the majority of the light bounces around the room, ending up as heat.

Heat is the lowest 'grade' of energy, which is why it is quite strange to use electrical energy to make heat (except in NZ, where apparently 70% of electricity is from hydroelectric, and they have 'heat pumps' so you get 3000W of heat out, from maybe 1000W or less of electricity in!

[rh77]

Heat is the lowest 'grade' of energy, which is why it is quite strange to use electrical energy to make heat (except in NZ, where apparently 70% of electricity is from hydroelectric, and they have 'heat pumps' so you get 3000W of heat out, from maybe 1000W or less of electricity in!

Many of us in the 'States have Heat Pumps, which are on the higher-end of efficiency scale for the mass market. The problem is, the "Heat" part only works at 40F+ -- otherwise, the system freezes. So, it kicks-on a backup. It's not practical in colder parts of North America.

Backup or "Emergency" heat as the thermostat is quoted to call it, is generally either gas or electric. My old apartment had electric coils as backup, which was REALLY costly. My house now has a natural gas backup, which would be OK, but the darn unit that came with the place is very inefficient. So, for those rare occasions it's 40-50F and heat is required, it works great, but the other 98% of the time is burns a bunch of gas :(

RH77

[Gearshredder]

actually, since it has been getting colder here, the oven has been used ALOT more than the summer. basically the oven was never used at all.

One thing i don't get (a lil off topic, not subject), Why is it that you can create heat by using energy but you ALSO have to use energy when you cool. (acctually ur just using energy for moving heat). But what im saying is, why isnt there a way to capture heat and turn it into power (yes, yes, sterling engine, but you need a difference of temperature to make it run) but using solid state tech. i.e. plate that absorbs heat and use to power other things.
Or is there, but we haven't found it yet?

[skewbe]

There are passive cooling systems, i.e. a large heat sink, that do not require additional energy. It relies extensively on a difference in temperature though as do most conventional energy converters.

Imagine you were in a sealed room, the observers increase the pressure to 5 psi, and then say to you "ok, turn that extra pressure into a continuous source of energy". Where would you start?

[trebuchet03]

But what im saying is, why isnt there a way to capture heat and turn it into power (yes, yes, sterling engine, but you need a difference of temperature to make it run) but using solid state tech. i.e. plate that absorbs heat and use to power other things.
Or is there, but we haven't found it yet?

There is :) Use a Peltier effect plate backwards and you get a current -- this is called a thermocouple ;)

But remember, entropy will win and defeat us all! Entropy, if you didn't know, is (in a very basic sense) a quantity of heat that can never EVER be used for useful work or recaptured. Every time you do work, entropy is created. Bugger :p Entropy is the reason why 100% efficiency is not possible (unless you assume reversible conditions - which are not possible in the real world) :p

[skewbe]

this is called a thermocouple


It still needs a temperature differential to work.

So is there anything special about a solar cell (http://en.wikipedia.org/wiki/Photovoltaic)in this regard? What if you could make one that responded to infrared radiation, would it care if it was bathed in heat?

[Gearshredder]

blah.. ok haven't gotten to that part in science yet :p (still in hs)
what i have learned: Entropy = stupid :)

[trebuchet03]

It still needs a temperature differential to work.


That's what I mean by "Use a Peltier effect plate backwards" --- give a thermocouple a current, it will make a temperature difference :P Give it a temp. difference, it will make a current :p

So is there anything special about a solar cell in this regard? What if you could make one that responded to infrared radiation, would it care if it was bathed in heat?

PV panels in space aren't bathed in heat :p

In any case, you can do some interesting things by using LEDs in reverse ;) Give a red LED some red light - and you should get a voltage over the leads :thumbup: This has been used for simple multi touch experiments among other things :)

[rh77]

Does this have anything to do with the 2nd Law of Thermodyamics...

I took a lot of bio-science classes instead, darnit :rolleyes:

RH77

EDIT: Crap, I can't edit the Title -- OK, I thought it was the third until I looked it up...my bad

[trebuchet03]

Does this have anything to do with the 2nd Law of Thermodyamics...

I took a lot of bio-science classes instead, darnit :rolleyes:



Pretty much :)

The second law says - you create entropy until you reach equilibrium and max entropy happens to be at the point of equilibrium.... Or something along the lines of - system order can not increase in a closed system (given no external energy source, you slowly diverge to disorder) - you know - no free lunch :p

So put a cup of hot coffee next to a glass of ice water... And you're an entropy terrorist! Contributing to the ultimate destruction of the universe :p


Although, if you destroy the universe (and thus space-time) - did the universe ever exist given the absence of time o.0 I mean, "infinite" and "forever" are until time ends - which is theoretically finite :p