What I miss about the Intel P4...

[Bozo]

The room heating ability. My "office" is down right chilly with two Core-2-Duo's running F@H. With the P4s, at least the room was warm. :-D

Bozo :joker:

 

[Stereodude]

Somehow I bet a space heater can affect the room temperature more per watt than a P4.

 

[Bozo]

Somehow I bet a space heater can affect the room temperature more per watt than a P4.

Actually, the P4s kept the room at ~80F even in the winter. The room is 12' x 14' in the basement with no other heat.
A space heater would be nice though. I might have to buy one now. The room is only ~60F

Bozo :joker:

 

[LunarMist]

Do you miss the P4 in the summertime?

 

[Bozo]

Do you miss the P4 in the summertime?

Yes. I have a small fan that circulates air through my office to the rest of the basement. (The fan is turned off in the winter.) That way it circulates through the de-humidifier. The P4s kept the room at ~70F.
The basement temperature remains at ~60F year-round.

Bozo :joker:

 

[RWIndiana]

Stereo, I think "heat per watt" is actually redundant. As far as I know, one watt hour produces the same amount of heat no matter what it is used for.

 

[LunarMist]

Yes. I have a small fan that circulates air through my office to the rest of the basement. (The fan is turned off in the winter.) That way it circulates through the de-humidifier. The P4s kept the room at ~70F.
The basement temperature remains at ~60F year-round.

Bozo :joker:

I confess to little knowledge of basements. They are not popular in the fault zones.

 

[Adcadet]

Another reason I'm looking forward to moving our office to the basement - it will heat it up.

 

[Stereodude]

Stereo, I think "heat per watt" is actually redundant. As far as I know, one watt hour produces the same amount of heat no matter what it is used for.

Not if you convert the electrical energy to mechanical energy or another form (like light). So, my comment in terms of heat per watt of electrical energy is correct in that context.

 

[Adcadet]

How much light or motion does your CPU produce???

 

[Stereodude]

How much light or motion does your CPU produce???

None, but the CPU isn't the only component in a PC that consumes power is it? There are fans, lights, and a monitor that turn some of the electrical power into something other than heat.

 

[sdbardwick]

and what happens to (all but a tiny bit of) the energy stored in the motion and photons? Hint: It has to go somewhere, and it doesn't get converted to matter.

 

[Stereodude]

and what happens to (all but a tiny bit of) the energy stored in the motion and photons? Hint: It has to go somewhere, and it doesn't get converted to matter.

It eventually ends up as heat, but that heat doesn't necessarily end up in your room.

Why everyone is so bound and determined to fight the point that a heater is a better heater than a computer is beyond me.

 

[RWIndiana]

I'm not trying to argue, but I don't understand how an electric heater could be any more efficient at producing heat than anything else, unless it's a heat pump. A fan, for example, produces very little heat at all. On most space heaters, this is the only thing that could produce motion/friction, and thereby (theoretically, in my mind) could produce just a little bit more. What am I missing?

Many heaters also produce light. Would that make them less efficient? I just don't understand how a watt hour of electricity could produce less heat if used in a different way, when all the "experts" say it doesn't. That specific amount of electricity produces the same amount of heat whether it's used to power a fan, a heater, or a light bulb.

And how could any amount of the heat produced by a computer or other electronic device not go into the room if it is fully contained by the room?

 

[Clocker]

I agree that it is a pointless argument. Bozo just go buy a heater!

But, RW is correct. Assuming the 'office' is an insulated control volume/system, we must follow the first law of thermodynamics as well as the law of conservation of energy. Any energy flowing into the insulated control volume that cannot leave it or do work on the surroundings is always eventually converted into heat energy even if it is first converted into work.

Now here's a question for you to somewhat illustrate the point....assume you remove your computer and you have only a freezer in your office. You accidentally leave the freezer door open just before you leave for vacation for for a week. How will that effect the temperature of your office?

If your freezer is 100% efficient, the temperature of the office will not change at all.

If your freezer is less than 100% efficient, the temperature of your office will actually increase because the extra work energy pulled into the office (in the form of electricity) to compensate for the freezer being less than 100% efficient is eventually converted into heat.

C

 

[Tannin]

RWIndiana is 100% correct here.

Same amount of electricity, = same amount of heat.

No ifs, buts or maybes. To claim anything else is to fly in the face of the laws of physics.

 

[jtr1962]

Maybe some of the light from the power or HDD indicator will leave the room, or some of turbulence from the case fans will affect air outside an open window, but it's nothing that could be easily measured unless you're at 6 decimal places. Essentially, power in=room heating, and that applies to all home appliances (except a clothes dryer which vents). It'll even apply if we develop LEDs which are 100% efficient at power to light conversion. Only the light lost out the windows (a small percent) won't go to room heating.

 

[Stereodude]

Well, you guys can keep using your PCs to heat your house and rooms. I'll use my natural gas fueled forced air heating system (furnace).

 

[RWIndiana]

Well, you guys can keep using your PCs to heat your house and rooms. I'll use my natural gas fueled forced air heating system (furnace).

Wise choice. Unless gas becomes more expensive than electric, that is definitely more efficient, fiscally speaking.

 

[ddrueding]

I'm looking into heat pumps for when I need to worry about such things.

 

[Adcadet]

The nice thing about space heaters and gas furnaces is they typically have some feedback system. My computers don't. Regardless, it's -5 F today, so I clearly need more than a few computers.

 

[timwhit]

So, what's more efficient an electric heat pump or forced-air natural gas?

I know there are a ton of factors. Like temperature, cost/Kwh and cost/therm.

My condo uses an electric heat pump and it seems to be very efficient unless the outside temperature drops below about 20° F.

 

[ddrueding]

Because of the factors you mention, comparing things that use gas to things that use electricity is too tricky for me, and likely impossible to generalize.

Heat pumps work much better if they have an underground heat source. Pipes buried in the ground give it a much larger source of energy than an ice-encrusted radiator.

 

[P5-133XL]

The real question is whether there is an actual efficiency difference between the heating capacity between different electricity devices i.e. Electric heater, Stove/Oven, Toaster, Computer? I personally don't see a big difference because 100W is a 100W and I really don't see a significant amount energy being converted into other forms like mechanical with these applications to cause an efficiency loss. So why isn't a computer as good as an electric heater for heating a house?

It's all well known that other energy sources can be much more efficient like gas, or a heat pump but aren't they a bit off-topic?

 

[Clocker]

So why isn't a computer as good as an electric heater for heating a house?

'Cause they cost a lot more to purchase and heaters are simpler/more reliable & usually put out about 1500W?

 

[ddrueding]

'Cause they cost a lot more to purchase and heaters are simpler/more reliable & usually put out about 1500W?

I'm not that far off

Not sure what I could add to up the number that much more...

 

[udaman]

I'm not that far off

Not sure what I could add to up the number that much more...

put a couple of GeForce 9800 GX2's

into your system, the resulting fire should put out lots more BTU than any space heater

http://www.electronista.com/articles/08/01/04/geforce.9800.gx2.9600.gt/

ChileHardware claims that the card may require a 400W power supply, putting it closer to par with Nvidia's current high-end models.

http://www.electronista.com/articles/08/02/12/geforce.9800.gx2.in.march/

 

[Tannin]

The real question is whether there is an actual efficiency difference between the heating capacity between different electricity devices i.e. Electric heater, Stove/Oven, Toaster, Computer? I personally don't see a big difference because 100W is a 100W and I really don't see a significant amount energy being converted into other forms like mechanical with these applications to cause an efficiency loss. So why isn't a computer as good as an electric heater for heating a house?

It's all well known that other energy sources can be much more efficient like gas, or a heat pump but aren't they a bit off-topic?

The thing is, Mark, that in a closed system, all forms of energy are ultimately converted into heat. For our purposes, a room in a house is a closed system, unless you want to start considering factors making a ridiculously small contribution to the total - JTR's example of a hard drive LED shining some tiny proportion of its light through a window and warming the street instead of the room is a good one.

Provided that we are consdering a closed system like a room, all forms of energy conversion result in heat, and with exactly equal efficiency.

Example: use 100W to run an air pump blowing bubbles in your goldfish bowl. (OK, so these are very big goldfish.) Let's say the pump is 22% efficient. (A wild guess, but as you will see, the figure cancels out so you can guess 1% or 99% if you want and it won't affect the final figure either way.)

So, for every 100W going into the pump, 100-22 = 78W is lost through mechanical and electrical inefficiencies and winds up as heat. 22W worth of electricity is converted into mechanical energy - pushing air through the tube - and all of that mechanical energy is, in turn, converted into heat.

Now, use that same 100W to power an incandescent bulb instead. Net room heating: 100W.

Or run it through your stereo speakers: still 100W worth of heat.

The only exception is where the system is not fully closed and energy escapes from the room to turn into heat elswhere.

Finally, remember that we can also ignore a lot of the inefficiencies of the room insulation. There is a draft under the door, let's say, which lets out 10% of the heat in the room. Even here, provided that the form of energy use within the room doesn't make the draft stronger or weaker, the same amount of heat is lost to the systerm, regardless of whether we input the heat via a kettle, a light, or a goldfish pump.

(Note that a fan might make a difference here, insofar as it might be blowing air out of the room; similarly, a focused light shining out through a window will be different, but these are rather fanciful examples.

Bottom line: 100W is 100W is 100W.

 

[Tea]

'Cause they cost a lot more to purchase and heaters are simpler/more reliable & usually put out about 1500W?

I have a Celeron 2800 in the workshop that seems to be putting out about 1500W right now!

A cruddy little Acer. We tried swapping the CPU but it doesn't make any difference, not to speak of; I think the motherboard must be putting way too much voltage through it. After a couple more CPU swaps and a fiddle in the BIOS, I decided it was hopeless and have replaced the board with a new Gigabyte one and a Sempron, which works just fine. Hope the customer doesn't mind me spending all her money like that!

 

[Howell]

Guys, you are missing the most important aspect of the discussion. You can't run f@h on a heat pump!

 

[Bozo]

So, for every 100W going into the pump, 100-22 = 78W is lost through mechanical and electrical inefficiencies and winds up as heat. 22W worth of electricity is converted into mechanical energy - pushing air through the tube - and all of that mechanical energy is, in turn, converted into heat./quote]

Not quite. Once the electrical energy is converted to mechanical energy, it is done. It is not converted again into heat. There may be some heat generated by the mechanical parts, but not (directly) by the electric.
Think of it this way: 1 horsepower = 746 Watts of electricity. If you had a 10HP motor, that would be 7460 watts of heat, according to your last sentence above. The motor would be glowing cherry red! A motor that is 80% efficient would use 80% of the electric and convert it to mechanical motion, the other 20% would be heat. The mechanical motion would not be converted again into heat. (unless the motor shaft was connected to something that produced heat)

Bozo :joker:

 

[Tannin]

You mean they don't have a heat pump driver available for download yet? Disgraceful! I'm switching to SETI!

Actually, you can get less heat out of a power-consuming device than the power you put into it, even in a closed system, but only in the (rare) circumstance where you are storing that energy in a different form - i.e., not actually consuming it at all. For example, you could start with a flat battery and instead of running a goldfish pump or a lightbulb or a Pentium IV, you could run a battery charger. Assuming that the charger is 10% efficient (another figure-out-of-the-air guess), only 90% of your 100W is heating the room. But (of course) you can then discharge the battery, which gets you that "missing" 10% back. Or you could do the same thing by pumping water up to a high tank (leaving you with potential energy in the form of water, ready to be turned back into kinetic energy, and thus (eventually) heat.

But let's ponder the efficiency of heating devices. Despite the fact that 100% of the energy in a closed system stays within the system, some heaters produce more usable heat per watt. How can this be? Didn't I just contradict myself?

No: there are at least two ways that heaters can vary in their efficiency.

(1) Heat vs usable heat. Consider an electric radiator at floor level vs an electric radiator 10 feet up a wall, pointed at the ceiling. Both draw 1000W, both (in our sealed room) add the same amount of heat into the room - but the former keeps your toes warm, while the latter merely warms up the already-warm air up near the ceiling, leaving your feet as cold as ever.

As a variation on this theme, compare an electric blanket with a space heater. To keep you equally warm at night, the blanket needs to draw maybe 100W (another guess), while the space heater needs to draw maybe 2000W. But the space heater is warming the entire room, while the electric blanket is only warming you. In thermodynamic terms, each is equally efficient, but in practivcal terms, they are in different leagues.

(2) Externalities. Consider my gas heater. Although it converts most of the energy in the gas it burns into heat (there will be a small amnount of unburnt gas remaining, maybe a couple of percent), a lot of thast heat never gets into the room: it goes up the chimney and warms nothing except the planet.

Does this mean we should all switch to electric heating? No, because electricity is (in the main) generated by burning coal or gas, and even the big industrial plants send a lot of wasted heat up the chimney. (Much less than a domestic heater, however.) Further, there are transmission and switching losses. (Any idea what the average figure is for that, JTR? Not your end of electronics, I know, but it's the sort of thing you just might know off the top of your head.)

 

[Clocker]

So, for every 100W going into the pump, 100-22 = 78W is lost through mechanical and electrical inefficiencies and winds up as heat. 22W worth of electricity is converted into mechanical energy - pushing air through the tube - and all of that mechanical energy is, in turn, converted into heat./quote]

Not quite. Once the electrical energy is converted to mechanical energy, it is done. It is not converted again into heat. There may be some heat generated by the mechanical parts, but not (directly) by the electric.
Think of it this way: 1 horsepower = 746 Watts of electricity. If you had a 10HP motor, that would be 7460 watts of heat, according to your last sentence above. The motor would be glowing cherry red! A motor that is 80% efficient would use 80% of the electric and convert it to mechanical motion, the other 20% would be heat. The mechanical motion would not be converted again into heat. (unless the motor shaft was connected to something that produced heat)

Bozo :joker:

Bozo your theory violates basic laws of physics. I've taken several classes about this very subject to get my undergraduate degree. I know the concept can be somewhat difficult to grasp at times because you have to be able to conceptualize somethings that cannot be seen...I guess that's the reason I had to take a class to fully understand it. Guess it wasn't wasted time after all!

All energy must be conserved. All energy tends to take the lowest form whenever physically possible. When you state that everything stops with the conversion into mechanical energy it implies that that the energy has some how left the system. It cannot leave the system. If the energy left the system, the basic principal of conservation of energy would be violated. In the end, everything is converted into energy of the lowest form possible (i.e. heat energy) unless it is stored as some other form of energy. For example, work done by fans creates friction with air molecules which, in the end, creates a tiny amount of heat between the molecules themselves as well as the fan blades. The only exception would be if some of the energy coming into the room was used to do Work & create stored/potential energy (i.e. stretching a spring and then not letting it spring back). That potential energy is stored until it is released again. In the end, All energy (kinetic and potential combined) is conserved and always tends to the lowest form of energy...it's just basic laws of physics and thermodynamics.

 

[jtr1962]

Leave it to SF to get such a simple topic off on some many tangents. :diablo: Well, looks like I'm getting pulled into the discussion again.

Let's start with that electric motor example. You all know I'm going to turn this into something with trains, so let's say the motor in question is maybe a 100HP GE 1240 or Westinghouse 1447 traction motor of the type used on NYC subway trains pre-1970s. Efficiency will vary widely depending upon speed, field shunting, etc. but let's say for arguement's sake the average efficiency of such a motor approaches 90%. There's power lost in the control gear, too, but that's fairly small compared to the power the motor absorbs. Anyway, for all intents and purposes roughly 10% of the power put into the motor goes into acutally heating it. Most of this 10% is transferred to the air via motor fans or the motor would indeed be glowing cherry red even being 90% efficient. So even on this level the motor isn't a closed system. However, let's look at the bigger picture. Where does the heated air from the motor go? Yes, it heats the subway tunnel. Now what do you think happens to the 90% of the input power which is turned into motion? Yep, same exact thing. Some of the energy put in accelerates the train. However, since the train eventually must come to a stop, this kinetic energy is all turned into heat by the brake pads. The wheels get hot from the brakes, and transfer that heat into the air in the subway tunnels. What about the energy used strictly to overcome resistive forces (i.e. rolling and aerodynamic drag)? Same thing-heat. The wheels and bearing get hot from rolling drag, and transfer that heat into the tunnels. The air stirred up by the train eventually loses its kinetic energy by bouncing off the tunnel walls, getting a bit hotter in the process. Even in cases where the train uses regenerative braking to put power back into the third rail when stopping by using the motors as generators, it all effectively turns into to....heat. That power is used by other trains but all is eventually heating the subway tunnels. It's just that regen (i.e. dynamic) braking lets you save on total power used, so overall you have less heating.

Now let's look at Tannin's question of electric heating. Should we all go to electric heat? Yes and no. No if we go to straight resistive heat and the electricity is generated by fossil fuel sources. Transmission efficiencies vary widely. Let's use 85% as a ball park figure. A large coal plant can convert maybe 60% of the energy in the coal to electricity. Overall then that's 51% conversion to heat via a space heater. By burning the same coal at home you might approach 80% or 90%. Of course, there are larger issues of distributed versus concentrated emissions (a factor which favors electric cars, for example). However, resistive heat isn't all you have. A heat pump can convert 2 to 4 times the input power to heat by absorbing heat from outdoors. Even counting the generation/transmission efficiencies, a heat pump, especially of the geothermal type, is the best system going once you get past the initial installation costs. We're actually going this route in time, perhaps even using solar panels for partial or total power generation. As to whether sucking heat from outdoors make it colder-the answer is no. The heat sucked from outdoors eventually leaks from the house being heated. In fact, the heat pump actually makes thing hotter on average outside because it absorbs power. But so does resistive heating to a greater extent.

 

[jtr1962]

Clocker basically just said the same thing as me but in fewer words. That's exactly what they teach in engineering schools. Heat is the end product of practically every process.

 

[udaman]

... Leave it to SF to get such a simple topic off on some many tangents....Clocker basically just said the same thing as me but in fewer words. That's exactly what they teach in engineering schools. Heat is the end product of practically every process.

Except, maybe not

Bose-Einstein condensate

http://en.wikipedia.org/wiki/Bose–Einstein_condensate

http://www.pbs.org/wgbh/nova/zero/

Slowing light down to a crawl, then back to light speed...how is this possible? Beam me up Scotty!

http://www.nature.com/nature/journal/v445/n7128/full/nature05493.html

Going off on another tangent, seems Lucy Liu was born in Queens, NY not far from jtr . And her father was/is a civil engineer, mother a biochemist...apparently did not pass on the brains gene, though Lucy did look naughty hot in bra and panties in last night's episode of Cashmere Mafia, lol, not exactly the prettiest Chinese woman, but then the TV show is about as dumb as a Darren Star ex-prod. soap gets, discounting Beverly Hills 90210 & Melrose Place. While I wasn't paying much attention while multitasking, I think the scene is at the very begging of the episode, where her b/f falls asleep on her abs, lol...you can watch the whole show on a tiny window from a link here:

http://television.aol.com/show/cashmere-mafia/1342100/main

http://www.tvsquad.com/2008/02/21/cashmere-mafia-dog-eat-dog/

(S01E07) "Good night, Jason." --Mia

And I think that's the last we'll see of the Chinese brain surgeon. What a catch he was though. Smart (well, obviously). Sweet. Attractive. Sleepy. Okay, that last one didn't go over too well. How could anyone, tired from neurosurgery or not, fall asleep on Lucy Liu's abs? She looked downright hot in that lingerie.

With all her millions---from movie roles, Ms Liu lives with her brother and his wife in NY, now there's a switch.

http://www.imdb.com/name/nm0005154/bio

 

[jtr1962]

Fascinating stuff all these altered states of matter. It would be kind of cool to slow a light beam down to the point you could actually get out its way, sort of like in that Trek episode "Wink of an Eye".

Speaking of Lucy Lui, she grew up in Jackson Heights, within walking distance of Astoria where I used to live until we bought the house in Flushing in 1978. And she graduated from Stuyvesant same as the three sons of one of my neighbors. The youngest one graduated in I think 1985 or 1986, so it's likely all three may have seen Lucy in school. It's a small world.

With all her millions---from movie roles, Ms Liu lives with her brother and his wife in NY, now there's a switch.

I could easily see myself sharing a larger house with my mother, brother, even sister and her family were I worth millions. Keep the 68 room mansions and servants and limos. I guess you could say Lucy Liu is low maintenance, unlike some people we both know.

 

[Pradeep]

Wise choice. Unless gas becomes more expensive than electric, that is definitely more efficient, fiscally speaking.

Of course the cost of natural gas/propane has risen significantly in the last few years. Prices have basically doubled in a 10 year timeframe. Costs me about $300 per month during winter to heat the house with natural gas, using a high efficiency gas furnace. It's a significant expense. And the low winter temps mean a heat pump is not an appropriate option.