Immersion and air cooling of mining asics

Ventilation with exhaust

Such a system is used in rooms with high ceilings, to which warm air moves. To extract it, an industrial fan is placed at the top. The air supply is carried out by any available method. It should be 2 times more powerful than the exhaust. This will reduce the pressure of the supply air and reduce the passage of dust into the server room. To retain excess debris, a grid is used for the incoming flow.

Rig cooling with exhaust and air supply

As of February 2022, mining of digital assets is possible using graphics cards (Ethereum, Litecoin, Monero). However, a single graphics adapter will generate little profit. Therefore, miners create farms of video cards, which are placed in special containers – regs. For their effective cooling, you need to install supply and exhaust fans. A mesh that collects dust is stretched over the racks with regs.

Ventilation of asics with exhaust and supply fans

A large mining farm on ASIC-devices requires an effective organization of heat dissipation. Especially if there is a question “how to cool asics in the summer”. To do this, you need to install industrial fans at the bottom for air supply and at the top for exhaust and organize cold and hot corridors in the room. This is done by fans on the ASIC equipment itself.

Inside the structure is divided into 2 parts by a polycarbonate wall. In it, holes are cut under the size of fans of ASIC-devices, which expel warm air into the hot corridor.

Minuses of air cooling

Most miners, to reduce the temperature of ASIC-devices, use fans that come with the kit. In addition, heat dissipation systems through supply and exhaust, as well as air conditioning, are popular. All of these are used to keep the ASICs stable and extend the life of the equipment. However, mining conditions differ between winter and summer.

For example, the Antminer S9 ASIC device consumes 1400 watts of power. A similar amount of thermal energy needs to be dissipated and dissipated so that the mining equipment does not overheat. With fifty Antminer S9s running, the ventilation system will have to pump up to 17,000 cubic meters of air per hour. You’ll need to bring in experts to design it properly. An inefficient heat dissipation system will lead to the following problems:

• Reduced clock frequency of ASIC hardware (performance will drop).
• Contamination of the farm with dust, fluff, debris and other small objects.
• Appearance of computational errors.
• Reduced service life due to overheating.
• In the worst case, breakdown of the devices is possible.

Immersion cooling of asics

Using a different coolant will avoid overheating of the equipment due to climate, temperature and weather. Immersion cooling of asics and video cards involves immersing them in a special heat-conducting fluid that does not allow electric current to pass through. 3M Novec and mineral oils are more commonly used for mining. These liquids do not disable electronics.

When to use

An immersion heat sink system is not necessary for all miners. It can reduce energy costs, but it is more often used by large centers for mining digital currencies. Also, mining companies use immersion system if there is expensive real estate in the area where the equipment is located.

It is not recommended to use immersion heat sink in residential houses and apartments. When repairing ASIC devices, the liquid can be spilled, and it is hard to wipe it off.

Dry water cooling

Novec is a liquid that is colorless and odorless. It belongs to perfluorocarbon compounds. It was first used to remove heat from transformers and extinguish electronics fires. However, in 2024, it is used by miners to cool video cards and ASIC equipment. Novec liquid is often referred to as “dry water” and has been manufactured by US company 3M since 1996.

Liquid vapor condensation

Novec solution is more often used by miners because of its low boiling point of 34°C, 49°C and 56°C (depending on its brand). The liquid that has crossed this threshold vaporizes and rises into the air. Subsequently, the solution cools down, condenses and is sent back to the equipment tank.

To vaporize 1 gram of Novec, 120 J of thermal energy must be expended. This value is low relative to the same characteristic of most existing liquids. ASIC Antminer S9 is able to vaporize 14 grams of solution in 1 second. This property makes it effective for heat dissipation.

Novec liquid and mineral oil

There are different substances suitable for creating an immersion heat sink system. The most common are Novec 7300 fluid and mineral oils. Their properties and costs are summarized in the table below.

Two-phase immersion cooling

In this system, the liquid changes into a gaseous state when ASIC equipment is heated. For its realization miners use Novec 7100 and 7300 brands. Devices are immersed in the liquid and the container is sealed. The equipment is heated, Novec vaporizes, and the gas rises to condensers with water, which cool it. This is how the working circuit of the heat removal system is formed.

Advantages of immersion cooling

Companies that produce such heat removal systems for ASIC devices, claim many advantages of the scheme. The advantages of immersion cooling are as follows:

• Overclocking capability. Immersion of devices in a special liquid allows increasing their computing power by 40%.
• Protection from overheating.
• Noise reduction. Sound vibrations inside the solution are damped faster, which makes the equipment run quieter.
• Protection from dust, dirt and debris.
• Self-installation. You do not need to call a specialist to set up a complex system of ventilation and air conditioning of the farm for mining.
• Electricity costs are reduced. Hong Kong-based cryptocurrency mining company Allied Control conducted a study that showed that electricity consumption is reduced by up to 90%.
• Space saving. ASIC immersion cooling allows devices to be placed very close together.

Summary

Efficient cooling of mining equipment is part of success when mining coins. The immersion system based on Novec liquid does an excellent job of dissipating heat. However, the high price prevents it from being used on a home cryptocurrency mining farm. “Dry water” pays off for large miners who are ready to invest large amounts of money in the organization of such a system.

Another option is mineral oil of a high degree of purification. However, due to its boiling point of 180°C, it is applicable for creating only a single-phase system. A pump is required to pump the oil through pipes to the external radiators. The pump power should be selected based on the viscosity of the liquid and its heating rate.

Frequently asked questions