Hi
Mining grin at home is fun and a great way to help the network grow, but with two working units and a small house with no basement to put them out of hearing range, I decided to try to make an immersion cooling system for my miners.
Parts:
- G1 mini miners - 2x
- used portable cooler box - 26l capacity with custom made lid
- ⲫ8mm copper pipe - 8m for heat exchanger
- circulation pump
- plumbing fittings, valves, hoses
- transformer oil - 20l
- bimetallic thermostat 60-70℃ range
- existing boiler for hot domestic water
Thanks to natural convection, the liquid flow rate around the radiators is enough to sufficiently cool G1 minis, so I removed all the fans. Luckily for me, the manufacturer chose to use thermally conductive tape on the chip, which is the best choice for liquid cooling (thermal paste gets washed out with time).
Existing pipes on the boiler heating coil loop were cut and tees with valves were inserted to connect to coolbox plumbing.
8mm copper pipe was shaped to fit inside the coolbox using a hand pipe bender.
A simple bimetallic thermostat is used to control the circulating pump . When oil reaches 70 deg C, the thermostat kicks in and the pump starts pumping hot water to the boiler. After temperature falls below 60 deg C, the thermostat shuts the power off. The whole cycle takes around 30min.
First clip - testing.
https://youtu.be/uXO_W_QijnI
The sound in the background is the heat pump kicking in. After a couple test runs, I’ve noticed that placing the circulating pump at the hot end of the loop is not a good idea. Hot water leaving a thin hose decompresses and generates cavitation on the blades of the pump’s rotor, reducing flow to zero. Moving the pump to the cold section of the loop, right after the ¾ inch valve solved the issue.
Second clip - after 5 months of operation.
https://youtu.be/ystcIgkELew
At the beginning, I had used a thermostat with a temperature range of 65-75 deg C and it seemed that oil temperature was a little too high; inner walls of the box started to soften and deform (which is visible on the video). Switching to a lower operational range thermostat solved the problem; no further deformations.
Final thoughts
My initial idea was to heat all my domestic hot water with these two miners (it’s ~5kW/24h). Turns out, even after careful insulation of all pipes it is not enough for a 300l tank, but still their waste heat contributes to my daily shower. Maybe I could capture a little bit more heat by submerging PSUs too.
I’m very happy with my setup. It works silently 24/7 with no downtime. Moreover the power for my miners comes from photovoltaics, so my grins are as green as they can be.
I hope you enjoyed the reading and sorry for my English.
