Hydro cooling
Hydro cooling takes heat off the chips with water in a closed loop, and an external heat exchanger dumps it outside.
What hydro cooling is
Instead of heatsinks and airflow, the hashboards carry water blocks. A pump drives treated water around the loop: it picks up heat from the chips, carries it to the external heat exchanger, cools down, and comes back. The asic itself has no fans, which is why hydro models run radically quieter than air-cooled ones.
Water holds the chips in a narrow temperature band, and that is where the main gains come from: better J/TH, stable hashrate through the summer, and higher density, asics sit close together without fighting for air. Bitmain specifies water at 20 to 50 degrees and a flow of 8 to 10 liters per minute per asic; MicroBT lets the loop heat up to 70 degrees.
The price of those gains is infrastructure. The asic needs a pump group, a dry cooler or another external heat exchanger, filters, and proper water: plain tap water scales the loop shut. Hydro is no longer "set it on a shelf", it is a small engineering system that someone has to build and maintain.
In return, the loop's heat can do real work: warming a room, domestic water, a greenhouse. A 70 degree outlet is already a useful heat carrier, and some owners cover their winter season with it.
The short version
| Principle | water blocks, closed loop, external heat exchanger |
| Bitmain water spec | 20 to 50 degrees, 8 to 10 L/min per asic |
| MicroBT loop | heats up to 70 degrees |
| Noise | well below air cooling, the outdoor unit does the humming |
| In the catalog | 8 hydro models from Bitmain, 17 from MicroBT |
What to think through before buying
Price the system as a whole, not the asic. A dry cooler, pumps, piping, filters, and installation add a serious sum on top of the ASIC; for one asic it rarely makes sense, for a row of several it does.
The water has to be treated: distilled or deionized with an inhibitor, per the manufacturer's schedule. Saving on water ends with clogged water blocks, and cleaning those means tearing down the whole asic.
A leak is the scheme's biggest fear, and the cure is discipline: pressure test the loop before startup, put leak sensors under the asics, add drip trays. A properly built loop runs for years without incident; one built from garden hose floods the place in its first month.
Hydro also has a non-obvious plus for a home: the asic can live inside the building with only the outdoor unit outside, like an air conditioner. The noise stays in the street, the heat stays indoors.
Example
The Antminer S21 Hydro from our firmware catalog: same series as the air-cooled S21, but per-asic hashrate is higher, J/TH is better, and you can hold a conversation in the room with it. In exchange it needs an installed loop, and it only moves together with that loop. An air-cooled asic rides in your trunk; a hydro system is designed around the room.
Related terms
Where to go next on the site
Hardware
- ASIC Miner knowledge base
Guides
Software
- Software firmware
Questions and answers
How much quieter is hydro than air
The miner itself has no fans; what remains is the pump and the external heat exchanger. You can talk comfortably next to the ASIC, the noise load moves outside to the dry cooler.
What water does the loop need
Treated water per the manufacturer's schedule: distilled or deionized with a corrosion inhibitor. Tap water kills the loop with scale and sediment.
Can a miner heat a house
Hydro is the best fit for that: up to 70 degrees at the loop outlet is ready-made heat for underfloor heating or a boiler through an exchanger. In winter that is real money saved.
What happens if the pump stops
Chip temperature shoots up in seconds and the asic trips its protection. A proper system runs a backup pump or a flow sensor that cuts the load before anything overheats.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .