Cybercafe: Saving energy exhausting all PC's hot air to the outside.

[cerot]

Hi, i have a "Cybercafe" business and the city weather gets extremely hot in the summer (42c to 50c). Add the hot air exhausting from 8 Pentium 4 Prescott computers plus the people inside the building.

So of course to keep the temps cool the air conditioner is using a lot of energy (it's a 2 ton 13 Seer ductless mini-split).

I am here looking for opinions/help in a project i want to do to help reduce the energy bill, that's $450 in the summer months.

I plan to use some ducts to send the hot air exhausting from the PSU fan and 120mm rear fan of all the PC's outside of the building. All connected to a principal exhaust duct (aprox 6" to 8" diameter)

First i would like know if you think this will help reduce the energy bill substantially (20% would be great, even 10% if the thing is not too hard to do). The building (10ft x 18ft) kept air tight most of the time, with the door closed only opened when clients come, i have no idea if exhausting all the hot air form the computers without too much air coming from the outside could affect negatively the a/c making it work harder.

Any help will be greatly appreciated. Thanks..

 

[dextermat]

I can't help on that but if you find a good system patent and sell to other cybercafe : great idea man

 

[AsAnAtheist]

There's a list of things you will need to consider while building this exhaust venting system:

1. Length of exhaust venting. Longer= more low pressure points needed.
2. Material used (ensure it can withstand the heat for prelonged periods of time.
3. Sealing material (material used to seal the computers exhaust points to the venting system. Make sure they can take some warmth.
4. Joint connections. Having different computers requires different pipes of their own, how will they connect to the central?
5. Talk with firefighters, there may be regulations when running exhausts out of a building. Im sure there won't be any problems since your not really exhausting anything harmful however be sure to ask. Fire fighters can easily have you fined or shut down temporarily if they see fit due to not following regulations.
6. How will you exhaust the air? The hot air may travel 1-2 feet before requiring additional low pressure to move forward (aka a exhaust fan inside the pipes). This requires electrical wiring going inside, or a powerful exhaust fan system at the top of where the pipes all join into the central.

The longer and wider the venting system, the more low pressure points you need (fans) or at least the more powerful you need. I am not an expert on the subject so I wouldn't be able to help you calculate how many fans per certain distance of venting system. Having inadequate venting systems can easily lead to heat build up inside the pipes, and likely vent the air BACK to the original source of heat (the computers).


Have you thought of investing on building's insulation? That helps keeps cost down by keeping heat in/out (serves as a two way barrier in/out which you need to keep heat out) A lot of places including commercial areas (but specially residential) rarely have proper insulation which contributes to lower costs for AC/Heater.

 

[lafontma]

You can go at it another way.

Let's say each computer is using 250W of power. That means 250 X 3.4 BTU per watt = 850 BTU/h per computer.

8 of those will produce roughly 6800 BTU/h. Your 2 ton AC is good for 24000 BTU/h.

So roughly a 25% of your AC capacity is used to "eliminate" the heat produced by those 8 computers. I am supposing the computers are on 24/7. You will need to adjust the savings versus the actual usage of the computers. Also if people are using the computers to mostly browse the web, they are prb using closer to 150-200 W then the 250W i used.

You then need to evaluate the cost of piping the heat outside VS the economy you can make by removing the hot air.

 

[Paperdoc]

I would think this is possible without a lot of fans. BUT you're only planning half the job. You can NOT remove air from a building without replacing it with the SAME quantity of air. So if you get this exhaust system installed, it WILL force hot outside air to be drawn into the building (more than is happening now) through any crack that exists, and that air will require cooling down to room temperature by the AC system. In other words, the hot air you get rid of will be replaced with similar hot air, and you won't save money.

You should plan also to create a small SUPPLY air system that draws air into the building from outside but ONLY allows it to be delivered to the INTAKES on each computer. (This is parallel to an exhaust system that ONLY takes out air from the hot outputs of each computer.) Now, most computers are NOT set up with single air intake points, although some can be set up that way with intake fans. So, IF you could seal up each case and control intake at only one or two points, and feed those from an outside air supply, you'd get the missing half of your system. Alternatively, IF you could arrange to have ALL of the computer bodies in one central sealed box, you could arrange a single common outside air duct into the box and individual exhaust connections to each, with appropriate fans. You still would have to do some fiddling around with this system, because instead of supplying 22C pre-cooled air (the room, via the AC system), you'd be supplying 50C outside air, and the internal components would really run at higher temps than now. Then you'd also have the problems of how users access USB ports and optical drive slots - add external hubs and drives to each machine?

So, let's run a few simple numbers. For every 100 cfm of warm air exiting the computers that is captured by your exhaust system and routed out of the building, you would suck into the building the same 100 cfm of outside air at 50C. That air would have to be cooled down to 22C (or whatever room temp is) by the AC. Costs money. Alternatively, look at what you have now. That 100 cfm of computer exhaust air is staying inside your building and must be cooled down to 22C the same way. BUT what is its temperature as it exits the computer case? Is it cooler than the 50C temperature outside the building? Then it is cheaper to continue operating as you are - an exhaust system would only INCREASE your cooling costs, plus add a bit for exhaust fan operation plus initial installation costs.

So, to decide whether it's worth it, simply take a thermometer to the air exiting the computers' cases. If is is COOLER than outside, leave it all alone.

 

[JackNaylorPE]

Correction....must obey the laws of conservation of energy.....if each computer is using 250 watts of power and the PSU's are 80% efficient, that means only 20% of the power is being wasted as heat....or 50 watts per puter.

The most comparable pre manufactured system for the OP to look at would be a commercial cyclone dust or sawdust collection system. Any hesat exhausted must be weighed in against that each CFM out must be matched by a CFM in from the hot and humid weather outside as well as energy consumed by air moving equipment and heat losses thru ducting.

 

[lafontma]

Correction....must obey the laws of conservation of energy.....if each computer is using 250 watts of power and the PSU's are 80% efficient, that means only 20% of the power is being wasted as heat....or 50 watts per puter.

The most comparable pre manufactured system for the OP to look at would be a commercial cyclone dust or sawdust collection system. Any hesat exhausted must be weighed in against that each CFM out must be matched by a CFM in from the hot and humid weather outside as well as energy consumed by air moving equipment and heat losses thru ducting.

Correction on the correction. The PSu is emitting only 50w but you need to had on the devices that are using that 200w. CPU, GPU, etc, as mentionned law of energy conservation

But i did forget the fact that the expelled air needs to be replaced as mentionned above.

 

[bmxdave]

Place the PC's in a remote location, like a closet, and ventilate that. It seems too inefficient to try to individually direct heat away from each PC. Your only costs would be some cabling and possibly some plywood, drywall, and 2x4's.

 

[welshmousepk]

Place the PC's in a remote location, like a closet, and ventilate that. It seems too inefficient to try to individually direct heat away from each PC. Your only costs would be some cabling and possibly some plywood, drywall, and 2x4's.

you're suggesting he puts his customers into closets?

 

[bmxdave]

you're suggesting he puts his customers into closets?

Hah, no just the PC's. Run cabling for the monitors, mice and keyboards to the individual desks, I've seen this done in quite a few places.

 

[JohnnyLucky]

50C = 122F

WOW! That's Hot! And I thought it was hot down here in sunny southern Arizona. At least it's a "dry heat" here. :lol:

I can understand wanting to exhaust hot air from computers. The problem is cooling the incoming hot air that replaces the exhausted air. It has to be cooled too. Doesn't seem like there would be much energy savings.

 

[welshmousepk]

a better, more efficient aircon seems like the best idea.

 

[AsAnAtheist]

a better, more efficient aircon seems like the best idea.

Too expensive. Air conditioning is one of those places where labor/units are very expensive due to jacking up of prices.

A dust collection system would be an overkill in my opinion, not to mention be really loud if it's in the same room as the computers (usually dust collection systems are set into an isolated room.)


Anyways going on topic.

What I described is probably your best bet. Exhaust system with some exhaust fans. I would recommend 1 smaller exhaust fan in the pipes from the computer to the join where they all join. Then maybe 1/2 a foot another larger exhaust fan inside. This is all problematic since you need to run electrical wiring through it to power the fans.

One thing to consider if you don't believe you'll need exhaust fans is since this exhaust system goes from a point of somewhat high pressure (inside the computer) directly to the outside another point of even higher pressure (40c-52c air) the exhaust fans will be necessary. Without the exhaust fans you would actually be sucking air from outside into the computers since outside would=higher pressure/inside=lower pressure.

Remember air flows from high pressure to low pressure. A fan creates a low pressure point on the side where air is not blowing, and creates high pressure on the side that is blowing air. This is why you will need exhaust fans to create low points of pressure for the air inside the computer to move outside, and high pressure after the fans to prevent hot air outside from coming in.

In all actuality this system is very easy to make (can't exactly say the amounts of materials needed since I don't know how long the pipes will run/etc) the only issues would be the wiring for the fans. (Quite a bit of DIY)

 

[jitpublisher]

Replacing all the Pentium 4 Prescott processors with a 45nm core processors would probably cut the heat in half. That would pay for its self in about 6 months. If heat is a concern, I could not think of a worse idea for a gaming PC than one with a Prescott processor.
Building a system to vent the hot exhaust air outside would be really simple, not nearly as much to it as some people are inflating up to be. All you need is some simple ducting, and an exhaust fan. No problem.

 

[JohnnyLucky]

Slapping myself silly! I didn't even think of exchanging cpu's for energy efficient models!

 

[AsAnAtheist]

Exchanging CPU? You mean motherboard/CPU/probably ram since last I checked Pentium 4's rarely shipped from manufacturers with ddr2.
That's 8 computers. even the cheapest motherboard/cpu combo could run $80-$100, ram another $20-$30 per 1Gb.

CPU/Mobo costs
8x80=$640
8x100=$800

Ram
8x20=$160
8x30=$240

Total Expense minimum: $800
Total Expense with variations: $880 (cheapest cpu/mobo combo+$30 ram)
Total Expense with variations 2:$960 (expensive cpu/cheaper ram)
Most expensive: $1040. (Of course buying used is another way to save.)

Upon review i found the cheapest motherboard/cpu to be $71~ from newegg using the AMD Sparta processor, 45w am2. The cheapest motherboard I could find was a Jetway AM2.

$71~x8=$575.84 total.

In all honesty find out if your building is insulated or not. Often times insulation can provide a reasonable cut in energy bills.


@Ventilation systems are very simple, the only issue would be the exhaust fan's wiring that is all.

 

[jitpublisher]

Exchanging CPU? You mean motherboard/CPU/probably ram since last I checked Pentium 4's rarely shipped from manufacturers with ddr2.
That's 8 computers. even the cheapest motherboard/cpu combo could run $80-$100, ram another $20-$30 per 1Gb.

CPU/Mobo costs
8x80=$640
8x100=$800

Ram
8x20=$160
8x30=$240

Total Expense minimum: $800
Total Expense with variations: $880 (cheapest cpu/mobo combo+$30 ram)
Total Expense with variations 2:$960 (expensive cpu/cheaper ram)
Most expensive: $1040. (Of course buying used is another way to save.)

Upon review i found the cheapest motherboard/cpu to be $71~ from newegg using the AMD Sparta processor, 45w am2. The cheapest motherboard I could find was a Jetway AM2.

$71~x8=$575.84 total.

In all honesty find out if your building is insulated or not. Often times insulation can provide a reasonable cut in energy bills.


@Ventilation systems are very simple, the only issue would be the exhaust fan's wiring that is all.

Minimal expense if your electric bill is running you $450 per month. If you save $100 a month, exactly as I stated, it will pay for itself in about 6 months. Thank you for taking the time to write all that down.

 

[AsAnAtheist]

Minimal expense if your electric bill is running you $450 per month. If you save $100 a month, exactly as I stated, it will pay for itself in about 6 months. Thank you for taking the time to write all that down.

$100 month by switching processors? Im afraid you have a lot of guessing going on.

A computer to run on a monthly basis can be estimated by this equation:

watts (from wall)xhours used/1000*kilowatt cost (12 cents avg April 2009 perhaps 13 cents now?)=cost per day (multiply by 28 for months etc).


So let's take 1 computer using a prescott P4, no GPU's it appears as it's used as a cybercafe.

210 watt usage to be generous for the P4 prescott, let's say they open 12 hrs.

210x12/1000*.13x28=$9.17 cents per month per computer. So $9.17 x eight computers

Total cost monthly for all eight computers: $73.36

Tell me how will he save $100 per month when his current systems uses less then $73.36. Fine I will play your game let's say we gets 45w processors to save energy.

45w, a prescott is typically 115w maximum TDP. Realistically speaking the prescott uses 103w and the 45w amd processor perhaps 36w.

So the different in watts is 67 watts. How much is 67 watt difference?

67 (Watts) x12 (Hrs)/1000x.13x28=$2.93 per computer

That translates to $23.41 a MONTH for all eight computers in savings switching to a 45w processor.

At that rate you can expect to be done paying for the cheapest equipment upgrade in around: 2.85 years, around 34 months.

Like I said totally expensive upgrade from a business perspective. $800 tied up that won't even show green numbers until 2.85 years...

 

[jitpublisher]

$100 month by switching processors? Im afraid you have a lot of guessing going on.

A computer to run on a monthly basis can be estimated by this equation:

watts (from wall)xhours used/1000*kilowatt cost (12 cents avg April 2009 perhaps 13 cents now?)=cost per day (multiply by 28 for months etc).


So let's take 1 computer using a prescott P4, no GPU's it appears as it's used as a cybercafe.

210 watt usage to be generous for the P4 prescott, let's say they open 12 hrs.

210x12/1000*.13x28=$9.17 cents per month per computer. So $9.17 x eight computers

Total cost monthly for all eight computers: $73.36

Tell me how will he save $100 per month when his current systems uses less then $73.36. Fine I will play your game let's say we gets 45w processors to save energy.

45w, a prescott is typically 115w maximum TDP. Realistically speaking the prescott uses 103w and the 45w amd processor perhaps 36w.

So the different in watts is 67 watts. How much is 67 watt difference?

67 (Watts) x12 (Hrs)/1000x.13x28=$2.93 per computer

That translates to $23.41 a MONTH for all eight computers in savings switching to a 45w processor.

At that rate you can expect to be done paying for the cheapest equipment upgrade in around: 2.85 years, around 34 months.

Like I said totally expensive upgrade from a business perspective. $800 tied up that won't even show green numbers until 2.85 years...

Thank you again for pointing that out! Some very interesting numbers indeed! I am so short sighted sometimes!
I had really not even thought about the cost savings of running the PC itself because quite frankly, yes, that number is going to be pretty insignificant in the whole scheme of things. These are after all gaming machines and are going to be running under a fairly decent load most of the time, But hey, 20 bucks is 20 bucks.
You know I cut our plant electric bill over a thousand dollars a month by simply changing to a more energy efficient air compressor several years ago?
It cost about 25g's at the time, I believe it actually took a little over 3 years to realize the savings But now we are saving even more than a 1g a month since the electric rates have increased about 15% over what they were when we were running the old 120 horse Sullair system I had.

But again, the cost savings by using energy efficient equipment alone I completely over-looked.
Once you figure it out, please post more numbers so we can see how close we are getting to saving a hundred bucks a month. Only about $80 more to go. Come on, you seem like a fairly intelligent person, can you post those numbers, think hard now, I know you can do it.

 

[AsAnAtheist]

They're not interesting numbers just real numbers. You cannot compare changing a air compressor or a whole AC or Heating system to changing a few processors and expect it to pay for itself.
The OP is a business owner, purchasing all these upgrades is quite frankly a mistake. Sometimes you have to sacrifice luxuries to run a business, it's that simple. #1 Priority should be sales not the making of an energy efficient building. Any successful business owner can tell you they did not become the richest by having the best equipment they got rich because they sold through whatever means (marketing, location, market share, etc).

Another thing how do you know they're gaming computers?

 

[jitpublisher]

They're not interesting numbers just real numbers. You cannot compare changing a air compressor or a whole AC or Heating system to changing a few processors and expect it to pay for itself.
The OP is a business owner, purchasing all these upgrades is quite frankly a mistake. Sometimes you have to sacrifice luxuries to run a business, it's that simple. #1 Priority should be sales not the making of an energy efficient building. Any successful business owner can tell you they did not become the richest by having the best equipment they got rich because they sold through whatever means (marketing, location, market share, etc).

Another thing how do you know they're gaming computers?

Okay, I have tried to be nice.
Do not pretend to lecture to me about running a business, I have worked for the same company over 25 years, 15 of it as a plant manager. Among other things, my job is new plant startups and restructering past acquisitions, and turning losing business plans into profitable ones. We are an employee owned company, we are a large company, and our business does quite well thank you, even in these tough times. The way we are able to outlast many of our competitors and actually remain very profitable over the past year is that our company has very little debt. When one of our competitors gets into trouble, and they have a decent client base, we buy them, dismantle them, and fire the culture who have run the place into the ground, and absorb what is desirable of their client base.
Do you work in some line of sales? Your comments and figures and line of thinking, at least in these few paragraphs paints a picture of a person who's strength is in sales. Nothing at all wrong with that. Great sales people are what every business needs. But what I have found over the years is a person successful in sales generally is horrible at actually running a business and keeping it profitable, and in the end if we make a great sale person into a business manager, you will quickly lose your most valuable clients.

Actually, it makes really no difference. I made the OP a suggestion to help control the amount of heat generated in building by a bank of PC's, in hopes of simply lowering a bill for air conditioning. Whether he thinks it will work or not is up to him, and quite frankly I could care less if you agree or not.

 

[AsAnAtheist]

I never questioned your skills or credibility I merely am stating what a business logic would usually dictate.

Second I have a hard time believing you actually have run a business as an owner or manager and you yourself turn a failing business plan into a successful one, considering you just recommended he switched processors and would save $100 a month with absolutely no facts something witch any owner would dismiss as nothing more then a joke. In reality all he would save is $23 a month, which would end up paying it self in 2.8 years. Im afraid this would be fine if the initial investment was only $100-$200 but $800 is quite a bit to invest into a cyber cafe just to save what you would save..

I do not have a lot of experience as far as being a business owner goes however my father has spent his life working/managing his OWN/others' businesses and I am learning from him. He opened his shop in Mexico and had several contracts with state governments, American companies, banks, large Mexican companies he was making quite a bit of money by Mexico's standards (far beyond what the average was other there, actually around 20x the average (at that time 1,200 pesos was the average, he was pulling 20,000-30,000 pesos)

He teaches me and my sister to run a business as efficient as possible and has taught us in all his years of experience running his own business or managing another person's business he has never once presented a plan based on pure speculation with absolutely no basis what so ever. Doing so is an easy way to get fired, disregarded, stepped down in position, or if your lucky schooled.

I take the same business perspective when I give advice here. Take in budgets, expectations, and tools to work with and come up a plan to achieve the desired goal with the least effort or waste possible. The plan is then presented with raw accounting and or statistics if they are available. I will simply just not want into an employers office and say "I think switching to so and so will lead to a $100 cut in our energy bill." I go in with proof.

Something you learn in studying of science, argument, philosophy, business is that when you propose an idea, plan, theory, advice or goal the burden of proof falls unto the person who originally proposed the idea, plan, theory, advice or goal.

As you can see by my posts, I will usually provide detailed information on my advice to people. Whether it's numbers, theories/laws or other data it is there.
Where are your numbers?

 

[jitpublisher]

I am sorry, do I need numbers? The numbers you have posted as I said are very nice. It is just to bad that they HAVE NOTHING TO DO WITH WHAT I WAS SUGGESTING. Before you attack my knowledge, you should at least understand the issue. You attacked my opinion with facts, yes. But the facts you used were not relevant to my suggestions.

Oh, PS. If you would PM me, I will gladly tell you the name of the company I work for, the division I currently work at, where it is, and the web site.

 

[AsAnAtheist]

Replacing all the Pentium 4 Prescott processors with a 45nm core processors would probably cut the heat in half. That would pay for its self in about 6 months. If heat is a concern, I could not think of a worse idea for a gaming PC than one with a Prescott processor.
Building a system to vent the hot exhaust air outside would be really simple, not nearly as much to it as some people are inflating up to be. All you need is some simple ducting, and an exhaust fan. No problem.

Here you clearly state that switching to 45nm energy efficient processors would pay itself in 6 months. How when I already demonstrated it would take over 2.8 years.

Perhaps you did not understand the numbers very well but basically I posted:
1. how much it costs to run a Pentium 4 prescott computer if it was run 12 hrs a day at max load for every month.
2. How much energy you would save using an energy efficient 45w processor vs a 110w~ Pentium 4 prescott processor. Around 60w~
3. The difference in energy consumption was then calculated to find out the difference in energy savings between the two. Which turned out to be $23~ a month.

The numbers are relevant, if you read the OP wants to cut energy bill costs. What the your or the OP think doesn't change the fact that it would take over 2.8 years to pay off the $800 equipment upgrade saving only $23~. This is a very bad business move as $800 can easily be put into another 3-4 computer setups which can make up for the high energy costs. Say if he did want to go more energy efficient he could easily take $800, and put it elsewhere.

 

[welshmousepk]

@asan: he was talking about the reduced heat output saving on the Aircon bill.

i'm pretty sure your argument is getting a little out of hand here though. maybe you should just let the OP take a look at the info you've both posted. there is some very helpful info form both of you.