At the moment, the majority of miners (including large ones) use air cooling of farms. Nevertheless, sometimes there is information that somewhere liquid cooling systems are still used. Leaders of the crypto currency market – the Chinese – announced a liquid cooling project for mining at the hydroelectric power station in Georgia, but there are no reports from the finished facility.
Actually, the air is the cooler of the mining farms. This leads to a contradiction connected with the fact that air is a heat insulator and is successfully used in this capacity in everyday life.
The thermal conductivity of air is 0.022 W / (m · K), and the heat capacity is 1 kJ / (kg · K).
For comparison, water has 0.6 W / (m · K), and 4.2 kJ / (kg · K).
It turns out that the thermal conductivity of water is 27.3 times higher, and the heat capacity – 4.2 times, respectively, we get that water is 115 times more effective as a coolant. But this is not all, the heat capacity is calculated per kilogram, and if you take into account the air density of 1.3 kg / m³, it turns out that 1 liter of water will replace 88,550 liters of air.
For clarity, here we have an example of a mine with consumed electricity. capacity of 100 kW:
For air cooling of such a room in summer it will take 30 000 m3 of air per hour! And even with this, the equipment will operate at the ultimate thermal mode. For comparison with water cooling, for a heat sink from a mine with an electric power of 100 kW, a half-inch central water supply pipe should be connected. This connection is realized for budget accomodation.
We shall get back to air cooling, ventilation equipment with a flow rate of 30 000m³ / h is not a cheap option, but this is not the only problem: you need to achieve a relatively laminar flow, which only high-level specialists can do (see the data center cooling device is a high-tech precision system). Just fans in the shed will provide turbulence, in which neighboring racks with farms will be cooled in different ways.
The next problem is noise. Fans give out 50-60 decibels, and silencers do not save much, it is necessary to mine away from residential buildings.
Further – dust, organic matter and so on … The Chinese put the farm in the mountains, but the whole problem does not go away. Dust, charged with static electricity, literally clings to the electronics, which on the one hand worsens the heat sink, and on the other hand, it is the conductor of small wandering currents. Therefore, there should be a staff of staff performing constant wet cleaning and purging of equipment.
As a result, you are either pawned in a specially equipped room with a professionally assembled ventilation and air purification system, and, in a good way, conditioning (similar systems add up to 40% more electricity) or you have the risk of overheating and equipment failure.
Advantages of immersion cooling over air:
- Increase in productivity,
- Reduction of energy costs,
- Increase the service life of equipment,
- Noiseless.
The installation of immersion single-phase cooling of mining from Beeminer Group
Beeminer created an immersion single-phase forced cooling unit called Hive 36. Installation for 36 any Antminer (D3, L3 +, S9).
Immersion cooling means cooling by “immersion”, i.e. ASIC is immersed in a heat carrier, while the heat transfer medium takes heat from the ASIC, which then passes through a pump to the heat exchanger. Heat from the heat exchanger is taken up by tap water.
Currently, the company has designed an installation for B8 (9 B8 miners in one facility), as well as a more budgetary version – for ASIC Antminer (for 6-12 pieces).
The company raises a “Hashrate” in various ways and disperses it from 10-15% to 30-40%. ASICs keep this overlock because they simply do not overheat.
Bluemead is a fluid that is the coolant used in the installation. It does not burn, does not evaporate, does not boil at + 200 ° С, does not freeze at -50 ° С and is inert: ASICs are not exposed to any negative influence.
Characteristics of the installation:
Water consumption in the installation: 2 m³ per hour at 50 kW / h.
Pipe for connection: ¾ inch (at good pressure in the network is only 0.5 inches).
Cable: 4 conductors of 25 mm² (copper).
The installation is connected to a 3-phase network.
Inside the shield there is a protective shutdown device (RCD), contactors, automatic control unit, power automatics, lighting, pump, additional outlets.
On each ASIC in the device is 1 automatic, for each ASIC there is a separate outlet.
