Eternal boredom during lockdown inspires the world's first crypto hot tub.
After the 3nd UK lockdown got the better of me I decided to try and create a hot tub heated from 100% crypto miner waste heat. Crypto mining throughout the world consumes the energy of a small country. Let’s find ways to manage the by-product… heat.
A few years ago I read a post on Lad Bible about a guy who heated his bath water using some Bitcoin miners. He looped the heated air from the miners round an intercooler from a Subaru Impreza, then warmed his bath water.
That guy’s a legend…. I just didn’t want the traumatic noise of the 120db Bitmain fans, these miner things are loud, think Boing 747 at takeoff.
Inspired by a trip to the gadget show in the UK some years ago I remember seeing a rack
of graphics cards and computer parts submerged in a tank of what appeared to be water. After asking a few questions I soon realised that it wasn’t water but dielectric
fluid, a non-conductive clear oil that transfers heat extremely well and does not
short out circuitry.
First step, strip and clean a miner, remove the fans and dunk in plastic container of
dielectric fluid. I switched the miner on and stood back. I was expecting
fireworks, a very large explosion or some sort of house wide blackout.
After a couple of minutes or so I had a plastic tank that was heating
up. Now I just needed a way to get the heat out of the tank and into some water.
After a little YouTubing and a bit of head scratching, I had found a way to transfer
heat from the miner fluid tank to a bucket of water. Let me intrduce “The Heat Exchanger”, comparable to the Flux Capacitor from Back To the Future this little beauty ticked all the boxes.
Can be found in most gas boiler systems all around the world. After a trip to my boiler
engineer buddy, I had everything I needed to see if I could heat up some water.
Quick detour past Screwfix to pick up some Push Fit plumbing
parts, 15 minute tactical garden shed raid and I was ready to go. Found a couple of pond pumps and some garden hose in the shed, realising this is when men “Keep Things Just Incase”.
Eventually after some tweeking and traumitc oil spills I dipped my hand in a bucket of 45-degree crypto heated water. I was once taught as a child engine oil, olive oil and bike oil are hard substances to clean up. My parents are wise, i’ve learned my lesson.
After I climbed head first into the warm bucket of water to celebrate I called the welding master and asked if he could cook me up a proper
tank. Against his will (as it was a weekend,) Tony from SteelWise Ltd spent a Saturday afternoon with some off cuts of stainless steel, a smile and some serious paitence. Nearing complete darkness and the blistering winter cold a few hours later we had a tank.
I redirected the hot tub circulation system with a couple of 22m taps to get the flow
of water and hooked up the heat exchanger and pumps to the mining tank. Called my crack pot electrician friend to bypas the pump, we were then properly in business. It took
22 hours to heat 9-degree baltic UK tap water to a tropical 43.5-degrees.
Hooked up a projector, streamed a classic 1996 American action thriller and cracked open a beer. Nailed it.
A word of advice…. 43.5-degree water is hot, hotter than I ever imagined. I won’t ruin it for you but think seaside restaurant in Thailand that specialises in lobster, cooked to perfection.
To be honest it’s had a few teething problems. I managed to blow 2 PSU’s when the pond pump
failed and the miners boiled themselves alive. This is what happens when you buy cheep Chineese pond pumps off Ebay.
After a quick chat to the amazing Grunfos UK Pump Tech Team, I’m now using a central heating pump. (They stress in no cirucustances should their pumps be used for this purpose). Through my limited expirence there is nothing more bullet proof in the pump world for the price so spin the wheel on other brands if you like. The whole thing has been running for over a month with no interaction. Learing from my origional tragic failures a Raspberry Pi now monitors the temperature and shuts everything down if things go Pete Tong.
Each miner makes between £2.20 – £11 a day depending on the price of crypto or if Elon Musk is trolling the crypto space with his twitter account. I’m mining Dodge Coin and Lite Coin with Bitmain Antminer L3+’s.
Hot tub blowers and pumps controlled via Alexa, and Siri just for good measure.
If anyone actually cares then I’ll update this page with a parts list – happy hot
tub mining people!