Topic: 3 BTC bounty for the best assistance! - page 2. (Read 4897 times)

you dont:  my original post:

I would only add that you do not need new cords, you can wire regular plugs for 220.  Just make sure you mark them very well so you dont plug a fan or a light into them.

also, I would use a commercial grade 20 amp outlet when wiring for 220.

They do but why would you want 110V?

they dont make 30 amp 110 volt plugs... 

Most of the cost is labor. Not much difference in outlet, breaker costs when it comes to 20A vs 30A.  Just go 30A from the beginning.  For safety I would go with locking connectors.

NEMA L6-30R outlet and plug.

Well, if you want to be code compliant, this probably wouldn't be a good idea.

A flat plate heat exchanger might not work very well (plates are very close together) but a tubular heat exchanger would likely be fine.  They are less efficient (heat transfer vs size) but you can always get a larger one.  If you have very hard water you will get mineral build up on the "well side" of heat exchanger but nothing an annual maintenance and cleaning couldn't handle.

Depends on the well.  Some wells will be tapped into a slow moving branch of an acquifier meaning any heat load short of a reactor is going to be insignificant.  Also "earth" is a decent heat sink.  Depending on the depth of the well you have quite a bit of surface area.

Pumping the heated water to the bottom of the well is an option.  Likely need to do some experimenting.  Obviously one could experiment before buying waterblocks.  Heat is heat.  23 GH is likely 10KW?  10KW = 34,000 BTU/hr.

Simply find a heat source (like propane burner) which can heat water dumping 34,000 BTU/hr into the water loop and you got a good test.  No need to even buy a heat exchanger at that point.  The best system would be one that has two wells connecting to same water source (pump cold water out of well, pass through heat source, pump into "hot well").

Sadly I can't put a well on my land because if I could I would be looking into it. 

I would only add that you do not need new cords, you can wire regular plugs for 220.  Just make sure you mark them very well so you dont plug a fan or a light into them.

also, I would use a commercial grade 20 amp outlet when wiring for 220.

I would recirculate standard coolant throught a submersive heat exchanger in a closed circuit. Problem is the water in the well will heat.  Constant fresh water as to be flowing.

This solution might not be cost effective in the short term. It also negatively impact ecosystem.

Did anyone mention that 240 is more efficient ?

Unless you have a very clean well, you might gunk up the heat exchangers. I guess I hadn't ever thought of using anything except for a closed-loop recirculated system.

I am investigating whether water cooling would be cost effective.  I will have access to well water in the space, and could run several heat exchangers.....seems very efficient relative to AC. 

My only concerns are my lack of experience with waterblocks, and the high capital costs. 

As for the AC-

I was using a 1500W AC in a small space as I was growing my rigs and it worked great up to about 3.5GH.  So I would say you are talking about 6-8kW in AC.

3 phase is likely of no use for you.  The reason for 3 phase is to reduce wiring in datacenters.  Datacenters are "big" so they gots lots of long wiring runs.  So they run 1 3phase circuit to a rack an then split it out as 3x 1 phase 208V circuits.  They can power more gear from a single wiring run.    The issue is the gear to split out 3phase into 3 separate single phase circuits tends to be expensive and you don't really have to make any massive wiring runs for the gear will cost way more than you will save in wiring.  There are other advantages but they aren't really applicable.

Simple version is 3phase or not it will need to be converted to single phase before you plug it into your power supply.

The good news is that is a premises is wired for 3 phase in the US it almost certainly have a subpanel (and likely outlets) wired for 208V single phase (they take one leg of the 3 phase circuit and create a 208V circuit).  In the US if the premises isn't wired for 3phase then it is 120V/240V split phase (same as any residence or office).

So either way you will have power available @ 208V Single Phase and/or 240V "Single" Phase (technically it is split phase but nobody calls it by its correct name).

The main reason for using higher voltage (208V or 240V) is:
a) reduce the # of circuits needed
b) power more devices for the same amperage.
c) reduce power losses in wiring due to heat (power loss is based on current not voltage which is why transmission lines are thousands of volts)
d) improve efficiency of power supplies (ATX power supplies run ~2% to 4% more efficient at 240V)

Using a couple of high amperage 208V/240V outlets you can greatly simplify your wiring.

For example using a PDU like this you can power ~5 KW worth of rigs from a single (NEMA L6-30R) outlet.
http://www.ebay.com/itm/APC-Basic-Rack-Mount-PDU-1U-AP9571-208VAC-30A-IEC-320-12-C13-NEMA-L6-30P-/110850452157?pt=LH_DefaultDomain_0&hash=item19cf33aabd#ht_2994wt_1185

It has 12 outlets so you won't be running out as you will hit 5KW capacity limit first.



30A, derated to 24A (code compliance).
24A @ 240V = 5.76 KW
24A @ 208V =4.992 KW
APC made something like half a quadrillion of these over the years so finding them on ebay is easy.

Your entire farm could be powered by 5 outlets and 5 PDUs.  

I did a little research before rewiring my garage (did it myself, it isn't that hard if you can handle electrical work) and nothing IMHO beats these AP9571s.  30A circuit is going to power 50% more rigs than a 20A circuit so these PDU are more economical than 20A ones.  You may think well lets just go 50A.  I like your style but 50A connectors, plugs, receptables, cables, breakers, wiring, etc tend to be very expensive.  208V/240V @ 30A is the best bang for the buck.

I can't help you on the cooling though.

Theres not much to say... :

110V vs 220V: If I had choice I would take 220V given that breakers would be the same = 2x power for same amperage breaker (for instance: 110V * 10A = 1100W vs 220V * 10A = 2200W). Also power supplies which run on 220V have better efficiency by a few %.

3 phase: Just means they have 3 phases (somo motors need 3 phases to work properly - because each phase is shifted by 120° so this isnt the same as having 220V with 30A breaker (read down) - but for your purpose it is) and you can use all, so if they have 3 phase 220V with 10A breakers that means you can put a load on each phase of 10A -> (220V * 10A) * 3 = 6600W

About AC cooling better wait for somebody who knows more because I dont know much - i dont use it and it is economically not justifiable to cool only with AC because power cost would likely become significant % of your total power cost of mining farm. Except if power is cheap or free + you have breakers that support your whole farm + AC id rather use extra power on more rigs and use very little or no AC and more venting. Very very rough estimate would be around +-3-7kW depending on outside temperature, and power dissipated from your rigs.

edit: somebody was fast enough to write some before i finished writing an posted this

And you can wire 3 phase to your rigs just take each phase seperately and load it with rigs according to breaker spec.. Then take next phase and load it with other rigs etc..

Om nom nom a brand new space, a clean slate. Makes my mouth water. First things first: By all means, wire it up for 240V. All your existing PSUs will continue to work with it with no change in how your rigs work. They will additionally gain from 1 to 3 % efficiency by running on the higher voltage.

The largest expense will be putting in several outlets, but if they weren't there already, it shouldn't cost much more than wiring in 120v. Additionally, you may need to buy either new power cords with different plug ends, or new plugs to attach to the ends of the existing cords.

Remember that when using double the voltage, your amperage is cut in half. So, a rig that was drawing 10 amps will now be drawing 5. The wattage remains the same.

As for cooling: I am not sure of your location, so I don't know the ambient temperatures. How hot does it usually get in the summer, and how cold in the winter? What kind of cooling do you have in your existing locations?

Finally, 3phase power distribution is pretty much out of the picture in terms of wiring it directly to your rigs, although if it is available to the building that will allow you room for much expansion. The most common implementation of 3 phase power is a 480 volts, which you would need to step down to 240 volts with a large transformer (think about the size of a mini-fridge) for a full 200 amp at 240 volt panel.  Your local electrical contractor can tell you what you need and how much it will cost.

220v has less amps flowing through the wires, which should (theoretically) reduce heat, although you'll need to change all the breakers and stuff.

YES!  and it counts! 

Milk was a bad choice!





sorry, had to get it out of my system