Liquid cooling of any sort 101:
For now, putting aside how heat is getting into the primary fluid to-air cooling loop be it direct contact using cooling blocks, oil-immersion fluid to air, or a 2-phase liquid/vapor 'Hot side' to fluid to air setup:
#1) All heat flow calcs are based on using either BTU/HR or for heat loads over several kW, Tons
2) Conversion factors:
1kW = 3412.142 BTU/hr
10kW = 2.84345 Tons
A handy site is
http://www.rapidtables.com/convert/power/kW_to_BTU.htm and
http://www.unitconversion.org/power/kilowatts-to-tons-refrigeration-conversion.htmlThat covered, we come to basic laws of heat transfer between two objects or mediums. Again, for simplicity media heat capacities, thermal resistance of the heat exchangers used, Heat exchanges size and even flow rates is left out.
That leads us to:
3) Based purely on what temp we want to maintain at the load (miners) vs the temp the sink or where the heat is going (outside air, a large pond, a swimming pool, etc) the general rule is:
The amount of heat energy (power, BTU's whatever) that can be moved is directly related to Temp
load - Temp
sink or more commonly referred to as Δt.
Now to apply these basics to miners, 1st remember that:
a) miners are quite happy at say, 61C (141.8F). That's pretty toasty and more than uncomfortable to the touch.
b) Even using an extreme sink temp - in our case, eventually ambient air - of 50C (122F) we still have a pretty decent Δt With a more reasonable ambient air temp even better.
c) That in turn means we only have to dissipate enough heat into the sink (air) by using a honking big outside fluid-to-air heat exchanger to keep the desired miner tank temp where we want it. At a minimum you will need desired temp and Δt between that and the sink (air) along with BTU's or Tons to be dissipated to start sizing a radiator or cooling tower.
In summary, given that it is MUCH easier to transport massive amounts of heat energy in a fluid moving through pipes vs just moving a massive amount of air it gives a huge advantage
where feasible or appropriate. Liquid is of course much more compact on the load end (miners packed in tanks) and pipes are a helluva lot smaller/easier to route than air ducts. Only really big part is the sink end but since that is outside, not a huge issue to deal with.
To be continued...
