Topic: How to make Bitcoin home mining profitable again in 4 easy steps. (Read 1455 times)

In a lot of cases it does not pay off.  We have had multiple people talk about the heated floors and using bitcoin water cooled miners to heat them.  But in the end  they never do it.

What it comes down to is cost.  And air is cheapest compared to other cooling methods.   You can easily use a miner as a space heater though.

https://bitcointalksearch.org/topic/use-the-force-dont-waste-the-heat-1120213
 

 Doubtfull. That's only around 160 F, not much higher than most water heaters are designed to operate at. I think it would make more sense to aim at around 50C though to avoid scald issues or requirement to use a mixer valve.


 Not that big a dead with modern water heaters, they have good insulation for energy efficiency reasons.


 Not an issue for copper pipework, DEFINITELY AN ISSUE FOR PEX.


 No idea what they plan to price it at, but it would be a miner designed for water cooling and to make active use of the waste heat. I doubt there is a huge market for it but I can see some potential for the concept.

 BIGGEST issue I see with it is the need to turn it off in order to handle temperature regulation of the water heater, which limits the percentage of time you CAN mine with it. Even a 1100 watt element on a 50 gallon heater (I rewired my electric hot water heater for 110 to put it on a timer for ToD low-cost electric, and out of "be sure it's low enough power" ran it through my Brand power meter for a while) will only need 4-5 hours to completely heat the water up from a standstill. This thing would have to be VERY low power to avoid "have to shut it down" limitations.

 You would also have to bypass your upper element entirely, which isn't unsafe if you know what you're doing but isn't something I'd recommend to someone that has NOT worked with hot water heaters a lot, especially if you don't have a schematic of the wiring for the heater.

While I am skeptical about the economics of it, at least the physics here are so much better than a "mining light bulb" (which really doesn't need the additional heat).

It's been a couple of decades since I had an electric water heater. I am curious about:

- What's the typical pressure relief valve set for? Will the 70C temperature cause it to "blow"?

- Do you expect to still have the down-conversion from 220VAC to 12VDC outside the tank? I would seem likely, but warrants consideration.

- Assuming you actually connect up 12V to the "miner heating element", then you'll need to supply say 100A through it's connector, along with Ethernet?

- If the water inside the tank is 70C, then the loss through the insulation will be greater, right? This is great in the winter, not so much in the summer.

- As you mentioned, you'll need some kind of mixing valve to limit the actual water temp to say 45C. It's hard to know what the actual plumbing in the house would tolerate in terms of water temperature. I doubt anyone has done ratings, but I don't actually know.

- Would the miner need to be a variable hash rate in order to ramp up and down in terms of actual heat production? At startup, and during a rush, the water hitting the element could easily be 20C or less?

When I had to screw in a new element, the cost of the element was maybe $25. This would be a $1500 (or more) element?

Did not convince me since increase in difficulty and mining operations are causing any mining profitability to decay in accelerated levels. I don't think this accelerated decrease in profitability was taken into account in this plan.

Even a water heater has it's material limits, which are much smaller than the limits of difficulty increase.

No, the capital cost and heat loss and pump inefficiencies would kill any ROI.

As for the heat, wise component selection lowers that risk. All ceramic capacitors eliminate a major source of failure. Our original design was speced for 125C max however to lower cost we re-speced down to 85C. Temperature cycling is another failure cause that is mitigated by being tightly coupled with the water, limiting the maximum temperature swing thus limiting the the stress on solder joints. Another mark for longevity of the design is that it is a sealed unit meaning no joint corrosion or moisture absorption worries, that and being immersed in Novec fluid which is also used as solvent to clean acidic flux residue.

Wouldn't it be easier to just use water cooled miners for this?
However water heaters usually heat water to pretty high levels, which would not be sustainable for the miners in my opinion.

1. Shrink BTC miner to fit into a pipe
2. Fit pipeMiner as a replacement heating element for electric water heaters
3. ??
4. Profit

The full write up is here http://blog.bitheat.io/bitheater/

This is text but I can't be bothered to reformat so see the post for links

How can this ever work? A brief technical overview.
Shrink BTC miner to fit into a pipe
Fit pipeMiner as a replacement heating element for electric water heaters

Profit
The first challenge is the size of this miner. In order to reduce the cost, we are making it fit through a standard (US) screw in electric heating element opening. This makes the design requirements pretty extreme compared to a conventional open air miner. To aid in moving the heat from the boards and into the water, we will be employing the use of 3M's immersion cooling fluid (same stuff Bitfury is using in their newest data center). This fluid is the reason why we are even attempting to build this device. It has a few design requirements when building a sealed unit, but it removes all heat engineering from the design of the board and enclosure, allowing ultra high densities, and thus the small form factor we need to fit into existing infrastructure.

The second largest challenge is making sure you can still have enough hot water. Because we are trying to get 100% hardware utilization, the wattage going into the water is much lower than your traditional heating element. Therefore hot water recovery is much longer. This can be remedied by more storage (storage is cheap compared to silicon). Unfortunately we can't make your current water heater larger in terms of gallon capacity, so we aim to increase the heat capacity. Most water heaters operate around 40-50C. In order to get enough storage, we are planning to get the storage temp up to around 70C (mixer valve required to avoid potential scalding). This ~50% increase in heat capacity should be enough for ~24hrs of regular hot water use. The idea, is that you get one tank worth of hot water a day. So if you use 40 gallons of hot water, and have a 40 gallon tank you would probably be just short of your needs (depending if you used it all at once). However, our miner only uses the bottom heating element position, so you can still set the top thermostat to a lower setting to help in recovery for those higher use days. If this product would gain traction, we could build a phone app that could estimate the "state of charge" of the thermal battery (water heater). This could help the user load balance the use of hot water to ensure 100% utilization.

The third challenge is keeping a high enough ROI potential to allow enough incentive for the added effort of installation of our miner. This is not something we can avoid. It is the only way we can make home mining profitable again. Perhaps your water heater is already 8-10 years old. You could replace it before it fails, and install our miner while your doing something you would have to do in the next couple years anyway. Unfortunately there is no magic wand for physical infrastructure.
ROI Potential
Until we have the cost of the ASIC chips locked down it is very difficult to know the price, being they are going to be a very significant proportion of the overall cost. Of course, the price of the miner can be much higher if the chips are really efficient, as you will have additional revenue to pay for the higher end chip. We are trying to get a break even point no later than 18-28 months out. That way the perceived risk can be lowered. However, as shown in our ROI graph, the miner does not have the same cost structure as a traditional miner. Because of nearly no electricity cost, it is profitable for a very long time. We estimate the cost of our miner could be between $1200-$2200. For chips with efficiencies around .16 J/GH a $1200 price point would ROI in about 20 months, and have a 50% ROI in 40 months. But with BitFury's 16nm chip (.06 J/GH) it would ROI in about 6 months at a $1200 price point, and about 18 months at a $3000 price point, and a 50% ROI in 35 months. This really puts into perspective how this device has a pretty wide window of being profitable, given efficient chips.

It is difficult to say how much ROI is needed to make this product viable. Obviously as much as possible would be great, but the cost of chips is out of our control. With economies of scale we can lower our price and maintain performance, but we need some initial traction to allow us to expand (or to even get started for that matter). Please contact us and let us know what you think. @BitHeatOfficial If you have a minute to spare take our short survey, or our slightly longer survey that takes about 3 minutes. (Please take one, not both).

If you haven't already, please read our 4 part blog series about why we are going through all this effort to build this.
One, Two, Three, Four.