keep a small mining farm cool with only air conditioners.

[mikeywith]

I am trying to calculate the cooling capacity needed to keep a mining farm running, with the following in mind.

- No intake/exhaust fans, the farm must be sealed and noise kept pretty low.
- No immersion cooling.
- No water cooling.
- Electricity is dirt cheap.

I understand there are better alternatives to cooling down a mining farm (I do that myself) but for this farm, there are no options, so now I am not exactly sure about the setup.

First, let's run some math.

50*M30s or a total of 175KW which is 597,000 BTUs per Hour.

This means a total of 597,000 AC BTU should keep the farm at an "ok" temp, at least on paper.

We have access to 60,000 BTU split AC which means if we place 10 of them, we get a total of  600,000 BTU and the miners should (in theory) run cool, the average ambient temp is 29C / 83F, go to 95 in some days, and down to 20C /68F on some other seasons.

I am pretty sure the math above is correct, but what could go wrong with such a setup?



Also, do you think we can get away with less cooling BTUs during the cold seasons?

So ACs blow in the direction of the miner's intake, cools the miner down, air comes out hot on the other side of the room, and eventually rises to find it's way back to the AC intake to come out cold again, it's obvious that the exhaust space of the miner will always be a lot hotter, contrary to how data centers are designed where they suck the hot air and send it back to the cooling units, but that kind of set up will not be easy/cheap to implement.

Open to all thoughts, especially from those who ran some miners on ACs only.

[philipma1957]

Hmmm how big is the room?

It is an interesting problem since the room is sealed  and there is no effort to do a true cold /hot set of aisles.

How much power do the ac units pull. You have a downclock option if too hot in the peak temps.

I allow some mixing of hot and cold aisles it actually is okay to mix the aisles a bit.

In your case you want the two aisles to mix because the room is sealed.

so if you have perfectly separated hot cold aisles the hot aisle will over heat.

worst case I see is you may need 1 split near hot aisle and space the m30s to let air mix.

bigger the room the better.

[mikeywith]

Hmmm how big is the room?

It is an interesting problem since the room is sealed  and there is no effort to do a true cold /hot set of aisles.

How much power do the ac units pull. You have a downclock option if too hot in the peak temps.

I allow some mixing of hot and cold aisles it actually is okay to mix the aisles a bit.

In your case you want the two aisles to mix because the room is sealed.

so if you have perfectly separated hot cold aisles the hot aisle will over heat.

worst case I see is you may need 1 split near hot aisle and space the m30s to let air mix.

bigger the room the better.

Room size is 10m*6m*3m / 32ft*19ft*9.8ft.

Each 60k btu AC pulls about 6kw worth of power, basically 1/3 of the miner's power.

Maybe a few fans sucking air from hot side back to the cold? I would imagine putting an AC in the hot side is going to melt it.

[philipma1957]

Hmmm how big is the room?

It is an interesting problem since the room is sealed  and there is no effort to do a true cold /hot set of aisles.

How much power do the ac units pull. You have a downclock option if too hot in the peak temps.

I allow some mixing of hot and cold aisles it actually is okay to mix the aisles a bit.

In your case you want the two aisles to mix because the room is sealed.

so if you have perfectly separated hot cold aisles the hot aisle will over heat.

worst case I see is you may need 1 split near hot aisle and space the m30s to let air mix.

bigger the room the better.

Room size is 10m*6m*3m / 32ft*19ft*9.8ft.

Each 60k btu AC pulls about 6kw worth of power, basically 1/3 of the miner's power.

Maybe a few fans sucking air from hot side back to the cold? I would imagine putting an AC in the hot side is going to melt it.

can the cold air from the split be piped to the hot side.

so 10 splits all on cold side but pipe cold air on two to the hot side.

https://bitcointalk.org/index.php?topic=5454122.0

last photo shows a stand a lone ac with two tubes piping air in.

your inside splits should have a cold ac air vent. if you tube two of them to the hot side it will mix the air.

your problem is very close but not exactly the same as what we had.

we got the cold aisle and hot aisle perfect after months of trying.

but the hot aisle was too hot 🥵. becasue we could not vent enough hot air out due to limited vent space.

so we not let some cold aisle bleed into the hot aisle.

so we were 80f cold 105f hot
with the partial mixing
we are 85f cold 95f hot

this is working very well.

you are going to have to do something like it.

your room is bigger then my room is

20long by 8wide by 20high.

some links for vents and fans as your fan idea may be good.

something like this to move some hot air to cold side.
https://www.amazon.com/MOUNTO-COMBO-Heavy-Cylinder-25-foot/dp/B078HQD8DD/ref=sr_1_5?


something like this to move cold air from one split to hot side

https://www.amazon.com/Flexible-Insulated-Aluminum-Ducting-Ventilation/dp/B0BPKZ2FH7/ref=sr_1_8?

what they will do is even out the room

instead of 75 cold  105 🥵 hot 🥵

maybe 85 cold 95 hot.

with no venting or very little venting mixing cold and hot will be needed to some degree.

the exact degree I am not sure 🤔

I would love to see some photos when it is setup.

[stompix]

I am pretty sure the math above is correct, but what could go wrong with such a setup?

Not that much if you have temperature monitoring and you set them to downclock or even shut down if it goes off the charts, but there will be a few inconveniences:

Reality tight math, one of the AC units to underdeliver or fail and you're overheating the room, quite a small one, 5 extra miners means 5 3k heaters going full power in a one-bedroom apartment with 30 Celsius outside. Not funny!

Second is the airflow, just as Phil said, it's not going to really work perfectly as it does on paper, you're going to have a hot spot that is going to be way hotter than the entire room opposite the AC units near the ceiling where heat will be essentially trapped in this setup, so I would have two ducts on each side going straight to the back with an end fan and press the hot air with a cold flow for extra airflow and circulation.

So unless the building really heats itself during the day to above what you said due to direct sun, no shade, or materials, it should not be a problem. But, to be honest not really a thing I would want to be in charge of it.
Oh yeah, I'm curious about the end result, unless, of course, it's doxing somebody.

[mikeywith]

can the cold air from the split be piped to the hot side.

so 10 splits all on cold side but pipe cold air on two to the hot side.

They can't be piped by default, but with some ducting it could we could easily direct one or more ACs to blow air to the hot side of the room, sould not be too difficult to do.

Here is how thet look like https://www.daikinindia.com/products-services/floor-standing

They blow air from the bottom and blow at the top.

so we were 80f cold 105f hot
with the partial mixing
we are 85f cold 95f hot

How did that affect the gear temps? It's hard to know if gear would prefer 80f intake and 105f out, vs 85f in and 95f out.

@stopmix, whatsminers would tune lower when temps go up, not much work needed to underclock them or shut them down when needed, but the cost of the setup will be close to 20k, slightly above, would rather size everything correctly since this will be one huge risk to test.

My plan is not to go full blast at first, so maybe just 1-2 ACs and the right number of miners accordingly، that should give us a good overview of how things will be on a larger scale.

The next issue we would face is noise, we need to soundproof the room as much as possible, also not sure how noisy a dozen ACs outdoor units will be.

This is going to be a very complicated project to say the least, which is why I am trying my best to be prepared for all scnerio, have to study everything, consulted a few HVAC folks and none of them had a clue of an operation of such type, they all know the math as we do, but none seemed to fully guaranteed it would work. 

[philipma1957]

can the cold air from the split be piped to the hot side.

so 10 splits all on cold side but pipe cold air on two to the hot side.

They can't be piped by default, but with some ducting it could we could easily direct one or more ACs to blow air to the hot side of the room, sould not be too difficult to do.

Here is how thet look like https://www.daikinindia.com/products-services/floor-standing

They blow air from the bottom and blow at the top.

so we were 80f cold 105f hot
with the partial mixing
we are 85f cold 95f hot

How did that affect the gear temps? It's hard to know if gear would prefer 80f intake and 105f out, vs 85f in and 95f out.

@stopmix, whatsminers would tune lower when temps go up, not much work needed to underclock them or shut them down when needed, but the cost of the setup will be close to 20k, slightly above, would rather size everything correctly since this will be one huge risk to test.

My plan is not to go full blast at first, so maybe just 1-2 ACs and the right number of miners accordingly، that should give us a good overview of how things will be on a larger scale.

The next issue we would face is noise, we need to soundproof the room as much as possible, also not sure how noisy a dozen ACs outdoor units will be.

This is going to be a very complicated project to say the least, which is why I am trying my best to be prepared for all scnerio, have to study everything, consulted a few HVAC folks and none of them had a clue of an operation of such type, they all know the math as we do, but none seemed to fully guaranteed it would work. 

So far all gear is good I showed you the whatsminers they are within spec.

My setup is close to what you have but not the same.

I can get some air in and some air out not enough but some.
And we do 36k+36k BTU of ac.

We are at 165kwatts and the room is smaller.

The small mixing action is okay so far.

You are going you be like this.

The larger room size will help you.

The dependence on all ac will mean you need 24/7/365 temp monitor.

I have these going to 4 phones and an ipad

https://www.amazon.com/gp/product/B01N17RWWV/ref=ppx_yo_dt_b_search_asin_title?


https://www.amazon.com/gp/product/B08PKWPKM2/ref=ppx_yo_dt_b_search_asin_title?

[DaveF]

Flat out you need more cooling. Keep in mind the air conditioners are 60k BTU in a perfect world, the will likely be a little lower then that. AND keep in mind you will need some other networking equipment in the room that will generate a bit of heat. AND slip air conditioners also put out a little heat. (blower fan, electronics and so on 1 is not a big deal 10 will be putting out a couple of hundred watts) once again not much in the normal world but you are hitting up against the maximum cooling they can do as it is.

Either add 2 AC units or take out a few miners. OR be even safer and do both, a little less profit is better then: https://youtu.be/fxGgx3YCCAA?t=8

-Dave

[philipma1957]

Flat out you need more cooling. Keep in mind the air conditioners are 60k BTU in a perfect world, the will likely be a little lower then that. AND keep in mind you will need some other networking equipment in the room that will generate a bit of heat. AND slip air conditioners also put out a little heat. (blower fan, electronics and so on 1 is not a big deal 10 will be putting out a couple of hundred watts) once again not much in the normal world but you are hitting up against the maximum cooling they can do as it is.

Either add 2 AC units or take out a few miners. OR be even safer and do both, a little less profit is better then: https://youtu.be/fxGgx3YCCAA?t=8

-Dave

whatminers m30 can clock down to 3050 watts vs 3400. That saves 17500watts or 59500 BTU's in heat.

I wonder how much outdoor heat will affect the room.

If you down clock to 3050 watts you may be good.
If you do 10 ac on the cold and 1 piped to the hot.

you have 660,000 btu

and miners are dropped to 538,000 btu

660000x80% =528,000 btu.

So you have a 20% safety factor by adding 1 ac unit and clocking lower.

[mikeywith]

Flat out you need more cooling. Keep in mind the air conditioners are 60k BTU in a perfect world, the will likely be a little lower then that.

I believe this has to do with the quality of the AC and its climate rating, the ones I am looking to get are T3 rated, which means they should be able to keep their rated cooling BTU capacity at temps up to 52c.

AND keep in mind you will need some other networking equipment in the room that will generate a bit of heat. AND slip air conditioners also put out a little heat. (blower fan, electronics and so on 1 is not a big deal 10 will be putting out a couple of hundred watts) once again not much in the normal world but you are hitting up against the maximum cooling they can do as it is.

You are 100% correct in terms of the added heat by all the things you mentioned, but they remain a drop in an ocean compared to the actual load coming from the miner.

Either add 2 AC units or take out a few miners. OR be even safer and do both, a little less profit is better then: https://youtu.be/fxGgx3YCCAA?t=8

Would love to add a dozen more if it was all easy and cheap, as I said, this is a huge challenge really, those 60k BTU ACs are expensive, big, hard to install, and would probably be a bit noisy so the more we add the more noise we get, in fact as it stands right now I have no clue if we would be able to add the initial 10 pcs without going past the noise level we are trying to maintain.

What I am counting on here is the ambient temp, see according to my understanding of these BTU ratings, it's the amount of heat that can be removed per hour, which means if we were to picture a scenario as follows:

A miner using 3kw would generate 10,236 BTU per hour, so if we use a 10,236 BTU those BTUs coming from the miner will be kicked outside and the room temp will be identical to the outside temp.

Based on that (assuming it's correct) if the outside temp in the above example was 15c, then I would need less cooling, simply put, I don't need the mining room to be at 15c, I am okay with 30c, which means probably using half the 10,236 cooling BTU will be enough to keep the room at 30c while the outside temp is 15c.

Using that same example and doing with the assumption that I am okay with temps being as high as 35c, it means, as long as temps outside are not above 35c then a 1:1 ratio would do just fine (the compressor will be running 24/7/365 of course).

I am also counting on the fact that I will only need to keep the lower side of the room cool enough, the ceiling could be boiling hot and I wouldn't bother about it.

I am probably saying these things to make life easier lol, but we will only find out when we try, I spoke to a guy who ran 3*S9s in a 4m*4m*3m room using only 12,000 BTU AC, so 14k BTU of heat vs 12k BTU of cooling and he said the miners were running pretty cool during all seasons of where he had them (10c winter to 40c summer), he said the room was (warm to feel) in the summer, but the miners had no issues, so I am counting on something of that nature, I know I won't be able to sit or sleep in a 35c room, but I am sure those gears can survive, so no way I am giving them the joy of running extremely cool.

Another advantage the system should have is the fact that it will be 100% dust free, we just going to have to seal the door, and probably add a door air curtain to keep dust from getting in when opening the door, clean like-new miners should be able to handle slightly higher temps.

but, alas, as I said, this is a challenging project, it could easily fail, and we will have to test it one step at a time, in the summer, when things are hot, we will probably have to either add more cooling BTUs or shutdown/underclock some gears as you mentioned, but let's find out in a few months when we start working on the project.

I wonder how much outdoor heat will affect the room.

Please refer to my above explanation of how I 'think' outdoor heat will affect the room.

If you down clock to 3050 watts you may be good.
If you do 10 ac on the cold and 1 piped to the hot.

you have 660,000 btu

and miners are dropped to 538,000 btu

660000x80% =528,000 btu.

So you have a 20% safety factor by adding 1 ac unit and clocking lower.

Yes, this is one thing I really like about Whatsminer, after all, we could just start with 5-6 AC units, and underclock all gears to 2,000w and see how things go from there, the ideal way of doing this would be to run all gears at full speed during the average weather, and run them underclocked during the 1-2 months of heat, instead of adding way too much cooling just to run cool for 1-2 months.

[philipma1957]

Flat out you need more cooling. Keep in mind the air conditioners are 60k BTU in a perfect world, the will likely be a little lower then that.

I believe this has to do with the quality of the AC and its climate rating, the ones I am looking to get are T3 rated, which means they should be able to keep their rated cooling BTU capacity at temps up to 52c.

AND keep in mind you will need some other networking equipment in the room that will generate a bit of heat. AND slip air conditioners also put out a little heat. (blower fan, electronics and so on 1 is not a big deal 10 will be putting out a couple of hundred watts) once again not much in the normal world but you are hitting up against the maximum cooling they can do as it is.

You are 100% correct in terms of the added heat by all the things you mentioned, but they remain a drop in an ocean compared to the actual load coming from the miner.

Either add 2 AC units or take out a few miners. OR be even safer and do both, a little less profit is better then: https://youtu.be/fxGgx3YCCAA?t=8

Would love to add a dozen more if it was all easy and cheap, as I said, this is a huge challenge really, those 60k BTU ACs are expensive, big, hard to install, and would probably be a bit noisy so the more we add the more noise we get, in fact as it stands right now I have no clue if we would be able to add the initial 10 pcs without going past the noise level we are trying to maintain.

What I am counting on here is the ambient temp, see according to my understanding of these BTU ratings, it's the amount of heat that can be removed per hour, which means if we were to picture a scenario as follows:

A miner using 3kw would generate 10,236 BTU per hour, so if we use a 10,236 BTU those BTUs coming from the miner will be kicked outside and the room temp will be identical to the outside temp.

Based on that (assuming it's correct) if the outside temp in the above example was 15c, then I would need less cooling, simply put, I don't need the mining room to be at 15c, I am okay with 30c, which means probably using half the 10,236 cooling BTU will be enough to keep the room at 30c while the outside temp is 15c.

Using that same example and doing with the assumption that I am okay with temps being as high as 35c, it means, as long as temps outside are not above 35c then a 1:1 ratio would do just fine (the compressor will be running 24/7/365 of course).

I am also counting on the fact that I will only need to keep the lower side of the room cool enough, the ceiling could be boiling hot and I wouldn't bother about it.

I am probably saying these things to make life easier lol, but we will only find out when we try, I spoke to a guy who ran 3*S9s in a 4m*4m*3m room using only 12,000 BTU AC, so 14k BTU of heat vs 12k BTU of cooling and he said the miners were running pretty cool during all seasons of where he had them (10c winter to 40c summer), he said the room was (warm to feel) in the summer, but the miners had no issues, so I am counting on something of that nature, I know I won't be able to sit or sleep in a 35c room, but I am sure those gears can survive, so no way I am giving them the joy of running extremely cool.

Another advantage the system should have is the fact that it will be 100% dust free, we just going to have to seal the door, and probably add a door air curtain to keep dust from getting in when opening the door, clean like-new miners should be able to handle slightly higher temps.

but, alas, as I said, this is a challenging project, it could easily fail, and we will have to test it one step at a time, in the summer, when things are hot, we will probably have to either add more cooling BTUs or shutdown/underclock some gears as you mentioned, but let's find out in a few months when we start working on the project.

I wonder how much outdoor heat will affect the room.

Please refer to my above explanation of how I 'think' outdoor heat will affect the room.

If you down clock to 3050 watts you may be good.
If you do 10 ac on the cold and 1 piped to the hot.

you have 660,000 btu

and miners are dropped to 538,000 btu

660000x80% =528,000 btu.

So you have a 20% safety factor by adding 1 ac unit and clocking lower.

Yes, this is one thing I really like about Whatsminer, after all, we could just start with 5-6 AC units, and underclock all gears to 2,000w and see how things go from there, the ideal way of doing this would be to run all gears at full speed during the average weather, and run them underclocked during the 1-2 months of heat, instead of adding way too much cooling just to run cool for 1-2 months.

What we have found in the small dense under ventilated room is there are knees or cliffs of rocket 🚀 to the move temps.

Ie 95f outside temp all good inside the room hotspot 99f

but 99f outside temp runaway thermals room hotspot 117f

or 150kwatts 90f outside temp 94f in room
but add 6kwatts to 156kwatts and same room will shoot to 117f

you are going to find out your pivot points by under clocking say 2000 watts a unit.

good.

but 2200 watts everything will over heat like mad.

get a temp app for the phone set it to warn you then under clock ⏰.

[mikeywith]

What we have found in the small dense under ventilated room is there are knees or cliffs of rocket 🚀 to the move temps.

Ie 95f outside temp all good inside the room hotspot 99f

but 99f outside temp runaway thermals room hotspot 117f

or 150kwatts 90f outside temp 94f in room
but add 6kwatts to 156kwatts and same room will shoot to 117f

you are going to find out your pivot points by under clocking say 2000 watts a unit.

good.

Exactly what I expect/worry about, the relationship between room temp and hardware consumption isn't going to be linear, this is also true for air cooling, i.e I know when I underclock M30s from 3400 down to 3200, they get a huge drop in temps, going from 3200 to 3000 is good but not as effective, so without air flow, this should be even more noticeable, hot spots will be there, a single miner going online/offline could have a large impact on the whole room, this will require a lot of trial and error until we understand  "the place's behavior under different conditions" just like how you understand yours now.

get a temp app for the phone set it to warn you then under clock ⏰.

Ya I have got one, I get instant notifications for temps and humidity levels that I set, it's very helpful when you are not watching the farm, I think it's a must in every mining farm.

[DaveF]

Was thinking about it, and I don't know what the cost would be, but I wonder if you could get hire a programmer to work with the whatsminer API and the temperature monitors you have in the room.

As the temp goes up it throttles down the miners, as the temp drops it throttles them back up.

Would probably require a lot of trial and error and obviously a PC or 2 in the room but it might actually generate more BTC. If it's a cooler day or as the ambient temperature drops at night the miners clock up a bit. But, during the heat of the day they slow down to keep the temperature manageable.

Just a thought.

https://www.whatsminer.com/file/WhatsminerAPI%20V2.0.3.pdf

-Dave

[stompix]

What I am counting on here is the ambient temp, see according to my understanding of these BTU ratings, it's the amount of heat that can be removed per hour, which means if we were to picture a scenario as follows:

A miner using 3kw would generate 10,236 BTU per hour, so if we use a 10,236 BTU those BTUs coming from the miner will be kicked outside and the room temp will be identical to the outside temp.

Based on that (assuming it's correct) if the outside temp in the above example was 15c, then I would need less cooling, simply put, I don't need the mining room to be at 15c, I am okay with 30c, which means probably using half the 10,236 cooling BTU will be enough to keep the room at 30c while the outside temp is 15c.

Hmm, I'm a bit curious about this one since checking the manual on our farm (not mining, true farm oink oink) HVAC the rating in BTU stands on the amount of heat it can move from the inside to the outside.

So a perfect 1 000 BTU unit will be able to move out 1 000 BTU at 10C or 40C, but in your case if you produce 10,236 units of energy those have to be removed be it 10C or 40C outside, you need the exact same amount of heat to be taken out, what will change if the outside is 10C instead of 30C is the efficiency and consumption of the unit, again, this is if we talk about a sealed room that won't lose that much heat through the walls.

I might be mistaken on this but using only half of it will end up with the room temperature going up and up till it reaches the miner's exhaust levels since you have more energy being produced inside the room than you have taken out of it!

I spoke to a guy who ran 3*S9s in a 4m*4m*3m room using only 12,000 BTU AC, so 14k BTU of heat vs 12k BTU of cooling and he said the miners were running pretty cool during all seasons of where he had them (10c winter to 40c summer)

14k BTU in 48mc2 versus 600 in 180mc2 the ratio is all over the place.
And the most important thing is that if the outside is colder even by a few degrees the room will lose heat, so if this guy had a wall in the shade with 5 degrees below and you're exposed on all sides it will be even worse.

My take would be to start with half of it and see how it works out, you wouldn't be wasting money on equipment you won't be able to sue such as the miners or you won't overspend on air units and installments you won't be needed.

Oh, and reading about the sound, just went outside, 32C right now, our office units are Fujitsu whatsoever, and my phone screams 69DB next to one of the outside units, (we have them in the parking space, cause...well, management!) so you might want to check one of those live before buying it if the sound is a concern.

[mikeywith]

Was thinking about it, and I don't know what the cost would be, but I wonder if you could get hire a programmer to work with the whatsminer API and the temperature monitors you have in the room.

As the temp goes up it throttles down the miners, as the temp drops it throttles them back up.

Would probably require a lot of trial and error and obviously a PC or 2 in the room but it might actually generate more BTC. If it's a cooler day or as the ambient temperature drops at night the miners clock up a bit. But, during the heat of the day they slow down to keep the temperature manageable.

Whatsminers have environment/room temp sensor, located far from the hash board, on the upper part of the control board, and gives pretty accurate readings, those temps could be easily viewed with an API request, and then a command to reduce the power limit for the miner can be sent, shouldn't take much to have something like in place, I think AwesomeMiner already has a function to check the environment temp.

So it's either going to be an hour to two of coding my own script or reaching out to Patrick/AwesomeMiner to see if they have that in place, they usually implement most of the suggestions I give them (given that they make sense). so ya, long story short, that shouldn't be an issue.

Hmm, I'm a bit curious about this one since checking the manual on our farm (not mining, true farm oink oink) HVAC the rating in BTU stands on the amount of heat it can move from the inside to the outside.

So a perfect 1 000 BTU unit will be able to move out 1 000 BTU at 10C or 40C, but in your case if you produce 10,236 units of energy those have to be removed be it 10C or 40C outside, you need the exact same amount of heat to be taken out, what will change if the outside is 10C instead of 30C is the efficiency and consumption of the unit, again, this is if we talk about a sealed room that won't lose that much heat through the walls.

The efficiency of an AC shouldn't change based on outside temps, if does 1k BTU, it does 1K BTU regardless, now let's forget for a moment about mining, and let's just picture an empty room with little BTUs.

Now let's recall how an AC actually function.?  the inside unit will suck room air in and passes it to the evaporator coil of the internal unit, so that it would come out colder, and that same "room air" finds its way to the evaporator coil (outside unit) where the compressor, refrigerant, and pressure do their magic to cool that same air.

The whole process can only do so much, most places I read say 10-12c below ambient air temp (remember the outside unit that does all that sits in ambient temp), so for the same room we are talking about, if the outside temp is 50c, and the goal is to keep room at 20c while feeding the ac 50c room temps is not going to happen, so this is where the BTU calcs come into play.

To bring  a 4m*4m*4m room temp down to 20c where the ambient temp is 50c you are going to need a larger AC than to cool the same room to 20c where ambient temp is 30c, you will need the AC to do more BTUs per hour, this also explains why cooling isn't done instantly, as it's a gradual process, for the same example, when the AC first starts with room temp is 50c, the AC will suck in 50c air, bring it down to 40c, when the whole room is 40c, it starts sucking 40c air and it comes out 30c, all of that needs to be done fast enough before the room gains more outside heat.

So, BTUs are not related to ambient temps, but the overall cooling is.

So now, we can simply conclude that if the outside temp is 20c, and you want your room to be 20c, there is exactly zero BTUs that need to be removed, now what happens when you start producing heat inside the room?

Instead of using a miner as an example, let's use another AC turned on heating mode, so you have two ACs of the same size, one is hot to cold another is cold to hot, what would be the room temp when ambient temp  20c? since both do the same BTUs, they should cancel one another the room temp will still be at ambient temp, no?

If that's true (which I believe it is), what happens when you bring in another AC of the same size that is set on heating mode, so now you have 2 hot vs 1 cold? you end up with 1 hot AC since the cold ac will cancel one hot ac, correct?

How hot do you think that one lonely hot ac will bring the room temperature to? 10c above ambient temp? the room now is 30c, 20c? the room now is 40c.

Now replace that AC with a miner that does the same BTUs, which brings us back to my initial statement, if the ambient temp is 20c and you are okay with temps going to as high as 40c inside, you probably don't have to match the exact BTUs of the miners.

I could be wrong, but would like to know, how?

[philipma1957]

I down clocked all my whatsminers.

I used -10%
I used 3050 watts

Its 93f today and the room is toasty

[bettercrypto]

First, let's run some math.

50*M30s or a total of 175KW which is 597,000 BTUs per Hour.

This means a total of 597,000 AC BTU should keep the farm at an "ok" temp, at least on paper.

We have access to 60,000 BTU split AC which means if we place 10 of them, we get a total of  600,000 BTU and the miners should (in theory) run cool, the average ambient temp is 29C / 83F, go to 95 in some days, and down to 20C /68F on some other seasons.

I am pretty sure the math above is correct, but what could go wrong with such a setup?

Based on your story, the math calculation you made is correct. And in my opinion, there should be enough cooling capacity to maintain the mining farm in terms of temperature. Perhaps all that is needed is to adjust the ambient temperature or maybe the settings on the AC unit, which of course depends on the weather conditions.

[stompix]

The efficiency of an AC shouldn't change based on outside temps, if does 1k BTU, it does 1K BTU regardless, now let's forget for a moment about mining, and let's just picture an empty room with little BTUs.

No, the efficiency actually changes:



TC is Capacity PI is power consumption.
It's a pain in the ass-protected pdf file, but I'm pretty sure even your model has the same kind of manual.
Again, look at the pipe length, this rating above is for 5m linear, and once you count elevation it's a mess.

If that's true (which I believe it is), what happens when you bring in another AC of the same size that is set on heating mode, so now you have 2 hot vs 1 cold? you end up with 1 hot AC since the cold ac will cancel one hot ac, correct?
How hot do you think that one lonely hot ac will bring the room temperature to? 10c above ambient temp? the room now is 30c, 20c? the room now is 40c.
I could be wrong, but would like to know, how?

It will bring the room temperature slowly up till it reaches the exhaust temperature at which point they will probably shut down themselves.

Let's look at it from the thermodynamics point of view as heat is just energy:

At one point you have one extra unit of produced heat in a unit of time, if this process goes continuously in a closed environment, after 1000 units of time it's 1000 extra units of heat. In a million units of time one million units of heat!
This will not stop at any point if we don't assume the equipment will melt itself because you're still feeding more heat in that room every second than you extract, 10C, 40C, 100C, 300C it's like blowing into a balloon, the heat has nowhere to go.

Of course, this is in a perfectly sealed environment, so there is heat escaping the room through the floor and the walls, but if we talk about 30KW extra there is no way you will reach an equilibrium before you melt everything!
Especially since you also want to soundproof this room which will add to insulation and make less heat able to escape through the walls.

[philipma1957]

Well the what's miners can down clock a lot.

with freq set to -10% and power set to 3000-3050

I went from 3350 watts on most units down to 2536-2910

So say 2700 on average meaning a savings of 650 x 6  = 3900 watts

With 50 units that is 32500 watts saved. That's 110500 btu.

With my 6 pieces we did

552 th vs 652 th a drop of 15.3% hash

16200 watts vs 20100 watts a 19.4% power drop

So if you play with lower freq you can easy peasy save 100k BTU with 50 units.

Going back to doing 10 ac it should cool at best 600k BTU drop that to 540k BTU

But the down clock drops you from 597K BTU to 497K BTU

So a cooling power of 540k and a heating power of 497K which is a 10% safety factor.
After playing with my small hot room since 2018 I know that 10% safety factor may be good most days.

Also you can simply shut mining units off.

As you see below in the screen shot  you would turn 192.168.1.232 off as it pulls the most power and runs the hottest

[Powell]

Years upon years ago when I had our farm (2014) and we were using about 140-150A @ 208v I had a calculation that took all of that formula and then even converted it to how many TONs of a/c I would need. I will say as a few others have posted outdoor units can/will be loud.

Fast forward to today at my personal home.
I have a ~50ft x 60ft x 20ft (roughly 3000 sq ft) shop/garage that was built around 4 years ago. It has vapor barriers under with the concrete, every bit of insulation that can be done (minus bay doors, which I may do soon but they are automatic rollups so always been hesitant), 2x 5 TON A/C units that are mounted from the ceiling to cool it down. I live southeast of Houston so I am closer to the Gulf of Mexico which means humidity is something I always have to fight. One thing as a user or two posted is depending on time of day where the sun is hitting the building there will be hot spots in different places and that can take a wicked hit to things.

Another thing though is humidity, and this is where I've had friends that own HVAC companies say can be a large issue, and this did come up with my mothers companies small data center (we are a reseller for IBM/DELL/Pure Storage/etc. etc. so we have a large amount of equipment to demo) that you still have to battle humidity. Last summer I did not take that into account in my personal shop, I was just using the AC's to help pull humidity out. I was mining Etherium in Minerdude/Octominer chassis with 3090s and I started to notice the heatsinks/fans/etc showing signs of dew on them and oxidizing things. I was in no way overpowering my AC's considering the heat produced from that was no issue for the amount of BTU's available from the AC. After Eth mining was done I was getting annoyed because leaving cardboard, etc became a problem. I ended up recently adding 20,000 CFM in fans (just 2x wall mounted 10,000 CFM fans to cycle the air) and it has helped a lot when the AC is running where as before even with everything sealed humidity was still not manageable. Though in the evening when things cool down and the AC isn't taking as much load. I am having to add a large de-humidifier (shows up Thursday) to hopefully be the final peace of the puzzle.

Maybe someone else can chime in on there being a problem with humidity because lets say you in theory could keep close to ambient, there is still large risk of failure to equipment at that point from humid air taking its tole on equipment fast.