ok.. so I've been thinking... flat plate on cold water inlet vs. 2nd tank with sidearm heat exchanger...
I see the trade off as being: with the flat plate method, you are only getting benifit while you are taking a shower. Lets say the entire household totals 1 hour per day. you get maximum effenciency/minimum price with the flat plate, but only for (1/24) = 4.1% of the time.. the other 95.9 percent, you are getting nothing.
So the question is. how much heat are you recovering during that ~4% of the day? after doing some research (yer geeks, you know how to use google..) I found that 1 Kilowatt/hr will heat 409 gallons 1 degree. Lets assume you need a delta increas of 40 degrees.. so 1 Kilowatt/hr will cover approx 10 gallons. assuming 2 gallons per minute on the shower, the question is: does your water loop provide 1 kwh of heat energy every 5 minutes or less? If yes, then you are golden with the flat plate setup.
If not, then your water loop cannot keep up with your shower, and you need to extend the time where you are extracting heat. To do this, it seems to me the best way would be to install a 2nd tank (cheap/new or used.. ) with a sidarm heat exchanger. Put this inline with your hot water heater on the cold side instead of the flat-plate. While this is the more expensive option, in the long run it should pay off as you will be actually be pre-heating all the shower water instead of just some.
If like me, your needed temp increase is closer to 60 degrees, then the calculations lean even further in the direction of 2nd tank.
Alternatively, you could just install water saving shower heads... Ugg, I hate those things.
Sigg
Topic: (Updated w/ pics) Watercooled Rack of Servers - 50% completed (Read 10593 times)
I don't see why that idea would be expensive though. It seems like something that could be done for $20, and perform as well or better than a large plate exchanger. The biggest downside is the floor space and low SAF.
Copper loops, finding a hot water heater in decent shape, rigging up some water tight seals. I mean remember this isn't a science experiment. It is the water my family drinks. It doesn't seem worth it. Like I said it would provide marginally more recovered energy but hacking around with drinking water isn't my idea of a good ROI%. I also don't think you are going to find all the parts, supplies, connectors, and tools for $20 but even if it is was $0.00 I don't think messing around with drinking water is a good idea.
I think you are missing the point on the amount of water. 2 ft, 20ft, 20,000ft it doesn't really matter how much energy is in the loop. We aren't storing it for on demand use. That energy will be dumped out of the loop at the same rate regardless of how big the loop is.
Your points are valid, it would be significantly more work to ensure it was built well and safe. As for the amount of water, to efficiently transfer the heat you need a large amount of surface area. To have a large surface area without excessive restriction, you'd need a large volume. That requires more water with more stored energy.
I'd actually be very interested in your calculations for the plate heat exchanger you looked at, and what the stats are for your system in terms of flow rate and head pressure, temperatures and such. With 6kW, you have a lot of leeway for heating water, but looking at my own supply even in the summer the incoming cold supply is around 10C. Getting it to 30C requires a lot of power.
Its not about getting it to 30c. But it's sure as hell higher than 10c. Not much energy saved but free is better.
Beside, i'm doing it to help with the heat being dumped in the house during hot summer days.
Now, i'm not sure how well it work. I hoped high untill i saw ciuciu's pic. LOL
Any responsible human being wouldnt waste water like that. Clean water isnt cheap. Its infact more expensive than gasoline where i am.
I don't see why that idea would be expensive though. It seems like something that could be done for $20, and perform as well or better than a large plate exchanger. The biggest downside is the floor space and low SAF.
Copper loops, finding a hot water heater in decent shape, rigging up some water tight seals. I mean remember this isn't a science experiment. It is the water my family drinks. It doesn't seem worth it. Like I said it would provide marginally more recovered energy but hacking around with drinking water isn't my idea of a good ROI%. I also don't think you are going to find all the parts, supplies, connectors, and tools for $20 but even if it is was $0.00 I don't think messing around with drinking water is a good idea.
I think you are missing the point on the amount of water. 2 ft, 20ft, 20,000ft it doesn't really matter how much energy is in the loop. We aren't storing it for on demand use. That energy will be dumped out of the loop at the same rate regardless of how big the loop is.
Your points are valid, it would be significantly more work to ensure it was built well and safe. As for the amount of water, to efficiently transfer the heat you need a large amount of surface area. To have a large surface area without excessive restriction, you'd need a large volume. That requires more water with more stored energy.
I'd actually be very interested in your calculations for the plate heat exchanger you looked at, and what the stats are for your system in terms of flow rate and head pressure, temperatures and such. With 6kW, you have a lot of leeway for heating water, but looking at my own supply even in the summer the incoming cold supply is around 10C. Getting it to 30C requires a lot of power.
You could always do some kind of radiant floor heat in the winter...just a thought...
I don't see why that idea would be expensive though. It seems like something that could be done for $20, and perform as well or better than a large plate exchanger. The biggest downside is the floor space and low SAF.
I doubt you are going to find everything for $20. Copper loops large enough to have any significant heat transfer aren't going to be cheap. Still even if it was free this is the water my family drinks. Not sure I want to be hooking up some salvage hot water heater of unknown origin or quality.
I fully concede that a flat plate exchange on the cold water inlet doesn't recovery 100% of theoretical energy but is does recover a good portion, is cheap and simple and doesn't require potentially contaminating the water supply.
If I went the storage tank w/ heat exchanger route I would look for something like this:
https://www.signalmarine.com/p-51907-atwood-eh-20-electric-water-heater-wheat-exchanger-20gal-110v.aspx
If someone made something like this without the backup electrical heat it likely would be cheaper.
If you think about this water boiler business real hard you'll come to the conclusion that this second boiler is just stupid over the multiple heat exchanger idea. This doesn't save any power over the plate exchanger it just takes a huge amount of space.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
Are you sure on that? With the extra water heater, you should be able to get the preheater to the same temperature as your water block exhaust temperature. With plate exchangers, you're still limited by the power of your loop. If you're running the hot water full out and pulling say 10lpm, you would need to dump ~700W of heat through the exchanger to raise the water 1 degree C. You would need a massive amount of plate exchangers and a lot of water in your cooling loop in order to raise the water temperature to close to the exhaust temperature. That sounds a lot more expensive than getting a free or very cheap water heater and some copper tubing, and much more likely to cause pressure issues on your hot water line.
Why?
700W/C is pretty insignificant when you have a 6KW heat source.
The reality is the amount of energy used in domestic water heating is a tiny fraction of the heat produced by mining. Thus getting ultra max efficiency is silly & expensive for no real tangible benefit.
I did the math already. A $50 flat plate heat exchange will dump about 90%+ of the energy I used each month to heat my hot water. Spending hundreds more to try and get the last 10% (most of which is simply unobtainable).
Your belief that you need a massive heat exchange or more water in the loop (?) is simply incorrect. The amount of water in the loop is immaterial. 1 gallon in the loop or 20,000 gallons in the loop. The amount of ENERGY in the loop is the same (it is the amount of energy used by the rigs).
I you're wrong on the last point. Consider a simple closed loop system where you have a pump, a block and a radiator. Your exhaust temperature will be a function of flow rate and power. Whether you have 2 ft of tubing between the GPUs and radiator or 20 ft, as long as you're not dissipating much heat through through the tubing the water between the blocks and radiator would be the same. You have 10x as much water in the tubing in the second case though, and thus 10x as much stored energy.
I don't see why that idea would be expensive though. It seems like something that could be done for $20, and perform as well or better than a large plate exchanger. The biggest downside is the floor space and low SAF.
Are you sure on that? With the extra water heater, you should be able to get the preheater to the same temperature as your water block exhaust temperature. With plate exchangers, you're still limited by the power of your loop. If you're running the hot water full out and pulling say 10lpm, you would need to dump ~700W of heat through the exchanger to raise the water 1 degree C. You would need a massive amount of plate exchangers and a lot of water in your cooling loop in order to raise the water temperature to close to the exhaust temperature. That sounds a lot more expensive than getting a free or very cheap water heater and some copper tubing, and much more likely to cause pressure issues on your hot water line.
Why?
Flat plate heat exchanger on the cold water line cost ~$50 and provides a massive Delta T to the cold water. It recovers most of the energy needed and is both cheap and simple. The payback period is measure in weeks. While one can do more remember hot water isn't that expensive maybe $300 per year so complex projects start cutting into your ROI% pretty quickly.
While there are ways to recover more of the heat I just don't see them as viable. Hacking up an old hot water heater of dubious quality, building your own radiator, running copper loop (not that cheap these days), jury rigging some water tight seals all to get maybe another 10% to 20% of annual energy budget? It doesn't seem worth it. I am going to keep it simple.
If you think about this water boiler business real hard you'll come to the conclusion that this second boiler is just stupid over the multiple heat exchanger idea. This doesn't save any power over the plate exchanger it just takes a huge amount of space.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
Are you sure on that? With the extra water heater, you should be able to get the preheater to the same temperature as your water block exhaust temperature. With plate exchangers, you're still limited by the power of your loop. If you're running the hot water full out and pulling say 10lpm, you would need to dump ~700W of heat through the exchanger to raise the water 1 degree C. You would need a massive amount of plate exchangers and a lot of water in your cooling loop in order to raise the water temperature to close to the exhaust temperature. That sounds a lot more expensive than getting a free or very cheap water heater and some copper tubing, and much more likely to cause pressure issues on your hot water line.
If you think about this water boiler business real hard you'll come to the conclusion that this second boiler is just stupid over the multiple heat exchanger idea. This doesn't save any power over the plate exchanger it just takes a huge amount of space.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
In theory this would allow for greater delta T because it has longer time to build up the heat. Adding enough plate exchangers would do roughly the same however.
Probably the cleverest way to preheat hot water would be to get an old second water heater and put it before your main water heater - you can probably find a craigslist one with a burned out element or such. Instead of a heater element inside it, you would put a "radiator" inside of it for your water cooling. Since you can't open up the tank to put in a normal radiator, perhaps a dozen feet of pex or copper tubing inside the thing circulating your coolant would do the job. The best kind to modify would be an electric with two heater elements, as pictured below, so one element can be your coolant inlet, and one can be your outlet. You remove the elements, fish tubing from the top to the bottom, and shove as much extra pex as will coil around inside the water heater. Then the trick will be finding fittings that let the piping pass into the water tank and still seal the inlets where the tubing passes so they will hold water pressure.
Note that the city water pressure will want to collapse the low-pressure coolant tubing. Although it should resist this crushing pressure, your coolant pump should be right before the water heater pumping coolant into the exchanger. Also note that if the tubing/radiator inside the water pre-heater ruptures, this will allow 60-80psi of water pressure into your coolant lines, so an emergency coolant pressure relief valve should be installed where it can let out water to prevent a hose blowout inside your racks.
With such a setup, you could preheat 15C water up to 40-50C, as warm as the coolant coming out of the systems.
Note that the city water pressure will want to collapse the low-pressure coolant tubing. Although it should resist this crushing pressure, your coolant pump should be right before the water heater pumping coolant into the exchanger. Also note that if the tubing/radiator inside the water pre-heater ruptures, this will allow 60-80psi of water pressure into your coolant lines, so an emergency coolant pressure relief valve should be installed where it can let out water to prevent a hose blowout inside your racks.
With such a setup, you could preheat 15C water up to 40-50C, as warm as the coolant coming out of the systems.
That's actually a really ingenious solution. For a radiator, is there any reason you couldn't take the top off and either insert a real rad or a nice coil of 1/2" copper? You're using it as a tank and insulator, so even if the tank is sealed it's nothing that a Sawzall won't fix. The copper tubing would have no problem surviving 30-40PSI of external pressure.
Probably the cleverest way to preheat hot water would be to get an old second water heater and put it before your main water heater - you can probably find a craigslist one with a burned out element or such. Instead of a heater element inside it, you would put a "radiator" inside of it for your water cooling. Since you can't open up the tank to put in a normal radiator, perhaps a dozen feet of pex or copper tubing inside the thing circulating your coolant would do the job. The best kind to modify would be an electric with two heater elements, as pictured below, so one element can be your coolant inlet, and one can be your outlet. You remove the elements, fish tubing from the top to the bottom, and shove as much extra pex as will coil around inside the water heater. Then the trick will be finding fittings that let the piping pass into the water tank and still seal the inlets where the tubing passes so they will hold water pressure.
Note that the city water pressure will want to collapse the low-pressure coolant tubing. Although it should resist this crushing pressure, your coolant pump should be right before the water heater pumping coolant into the exchanger. Also note that if the tubing/radiator inside the water pre-heater ruptures, this will allow 60-80psi of water pressure into your coolant lines, so an emergency coolant pressure relief valve should be installed where it can let out water to prevent a hose blowout inside your racks.
With such a setup, you could preheat 15C water up to 40-50C, as warm as the coolant coming out of the systems.
Note that the city water pressure will want to collapse the low-pressure coolant tubing. Although it should resist this crushing pressure, your coolant pump should be right before the water heater pumping coolant into the exchanger. Also note that if the tubing/radiator inside the water pre-heater ruptures, this will allow 60-80psi of water pressure into your coolant lines, so an emergency coolant pressure relief valve should be installed where it can let out water to prevent a hose blowout inside your racks.
With such a setup, you could preheat 15C water up to 40-50C, as warm as the coolant coming out of the systems.
In your case when there was nothing connected to the motherboard wouldn't it have been easier to just tighten the links outside of the rig -> attach all the cards together -> place the whole stack on the mobo ?
I have never had luck with that. If you got 2 card you can do that pretty easy. But with 4 card trying to get all 4 to line up right is tough. You kinda need 5 hands.
In your case when there was nothing connected to the motherboard wouldn't it have been easier to just tighten the links outside of the rig -> attach all the cards together -> place the whole stack on the mobo ?
So I guess this was with the Swifttech links. Were they hard to press together vs phobya links?
Yes this is the first rig to use the Swiftechs.
The link has some resistance when adjusting the width of the link but not much.
I found it easiest to install it this way.
1) Unscrew the "collar" (gives you more room to get wrench on the connector).
2) Attach connector to the waterblock (side closest to the collar) *
3) Tighten w/ wrench according to spec.
4) Shorten the link as far as possible
4) Insert all cards into the rig (each is connected on only one side)
5) Attach other side of link **
6) Tighten w/ wrench according to spec
* My water blocks (Danger Den 5970) have a plastic top so I attached the links to that side of each card first (outside of rig)
** This is actually the hardest part. Kinda hard to get it started (small space, resistance from extending the link and getting threads started).
So far I am really impressed with these links. They are very very similar to the Koolance links ($15 ea) but are fitted to allow tightening with standard wrenches. I honestly can't believe they are only $8.
So I guess this was with the Swifttech links. Were they hard to press together vs phobya links?
DT: how many cards did you manage to convert during the weekend ?
Another 4. Fourth rig is installed. 16 down, 8 to go. God I hate installing waterblocks.
If FPGA didn't exist and I planned to rig up an entire datacenter like this I would have to find someone to install blocks for me.Will provide some updated pics this evening.
DT: how many cards did you manage to convert during the weekend ?
Why don't you wrap the tubes and cover the blocks with cellophane?
I think that would make the rigs a nightmare to maintain. Besides as it isn't the purpose to do extreme cooling here simple temp controlled fan killswitch would do. And a mag valve would do for the tap water cooler dude.
Why don't you wrap the tubes and cover the blocks with cellophane?
Okay, now that was good to know! This could easily happen to DT as well if you put your rad outside.. Although 24 GPUs would draw about 1060w while idle so there would still be a good amount of heat going in to the loop but if the fan blowing through the the rad keeps running full bore after the net is out temps would still drop rapidly and low.
A kill switch shouldn't be too difficult to do.
Ek blocks are half plastic but condensation would still happen on the steel plate some of the blocks have on top(5870V2 & 7970). Some condensation would also happen on the sides. I think the under side facing the card is getting some heat and the air doesn't move there as much so it is probably ok.
A kill switch shouldn't be too difficult to do.
Ek blocks are half plastic but condensation would still happen on the steel plate some of the blocks have on top(5870V2 & 7970). Some condensation would also happen on the sides. I think the under side facing the card is getting some heat and the air doesn't move there as much so it is probably ok.
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