Mining and harvesting water

[RealMalatesta]

Currently, I'm setting up a mining rig which is, imho, a bit unique.

I made the roof of my house with solar tiles. They produce the energy for running a couple of miners.

Under my house is a huge cave system, dug some hundred years ago. Down there, I have a constant temperature of 15° Celsius and a humidity of 92%. Which leads to about 5 to 6 Gramm water per square meter.

The box with the miners is placed in this cave. One ventilator is blowing cold air into the box with the miners, the hot air is blown into two copper tubes which lead through one cave and exit it at an exhaust. The copper tubes have all couple of centimeters little holes so that condensed water can drip out. This water is collected in a bin and pumped into a cistern for future use.

The next few days, I'm assembling everything and, if you are interested, I keep you updated about the progress.

[RealMalatesta]

The ultimate goal is to harvest enough water for the dry summers here and being able to irrigate our olives and oranges.

[Stalker22]

Why would you want to harvest water in such a complicated way if I may ask? That would only make sense in areas where water is an extremely scarce resource. Right? Still, isnt it much simpler to collect water from rain throughout the year and store it for dry periods?

[RealMalatesta]

Why would you want to harvest water in such a complicated way if I may ask? That would only make sense in areas where water is an extremely scarce resource. Right? Still, isnt it much simpler to collect water from rain throughout the year and store it for dry periods?

I do this, too. But this isn't enough in the long term. We also have a water well in 200 meter depth, but this is drying out within the next few years. Rain is less since years. But we have sun. A lot of sun. And the caves. So I thought to give this a try.

[NotFuzzyWarm]

Be aware that running 92% humidity air through the miners will very shortly kill them from the resulting corrosion it will cause...
Then you have,

One ventilator is blowing cold air into the box with the miners, the hot air is blown into two copper tubes which lead through one cave and exit it at an exhaust. The copper tubes have all couple of centimeters little holes so that condensed water can drip out.

Why is the water condensing? As I read it, you are blowing humid air that has been heated by the miners. Condensation is caused by cooling air - not heating it. The heating will actually make the air able to hold more water.

[Nexus9090]

Be aware that running 92% humidity air through the miners will very shortly kill them from the resulting corrosion it will cause...
Then you have,

One ventilator is blowing cold air into the box with the miners, the hot air is blown into two copper tubes which lead through one cave and exit it at an exhaust. The copper tubes have all couple of centimeters little holes so that condensed water can drip out.

Why is the water condensing? As I read it, you are blowing humid air that has been heated by the miners. Condensation is caused by cooling air - not heating it. The heating will actually make the air able to hold more water.

I think they're blowing the warm humid air into cold copper tubes, so the humid air is then condensing in the copper tubing providing water drops. Not particularly efficient but assuming the copper tubes remain below ambient temperature they'll allow condensation to form.

[RealMalatesta]

I think they're blowing the warm humid air into cold copper tubes, so the humid air is then condensing in the copper tubing providing water drops. Not particularly efficient but assuming the copper tubes remain below ambient temperature they'll allow condensation to form.

That's exactly what I'm doing. Not very efficient, I know. But I experimented with Peltier elements - the harvest is relatively small. Same with professional dehumifiers. The ratio of electricity input and water output is bad.

The positive aspect I'm seeing here is that I have the electricity basically for free over the years. The miners are old machines I still had in my basement, they have been written off a long time ago. Water is getting more and more scarce here, so every drop is basically money. And the mining revenues will be small, but hey: My daughter just called me and told me that she found a wallet I gave her 2013. Some Satoshis then, a lot of money for her today. So as long as I hodl, all is fine

But of course: I'm open to any kind of idea any of you has to make my setup more efficient!

(Btw: My cave is huge. I mean: HUGE. And in our town, the caves are spanning over a total of 14 kilometers. The mayor already announced that he'd like to see my setup. So in the best of all cases, we may turn into a little Bitcoin-mining-town)

[Nexus9090]

I think they're blowing the warm humid air into cold copper tubes, so the humid air is then condensing in the copper tubing providing water drops. Not particularly efficient but assuming the copper tubes remain below ambient temperature they'll allow condensation to form.

That's exactly what I'm doing. Not very efficient, I know. But I experimented with Peltier elements - the harvest is relatively small. Same with professional dehumifiers. The ratio of electricity input and water output is bad.

The positive aspect I'm seeing here is that I have the electricity basically for free over the years. The miners are old machines I still had in my basement, they have been written off a long time ago. Water is getting more and more scarce here, so every drop is basically money. And the mining revenues will be small, but hey: My daughter just called me and told me that she found a wallet I gave her 2013. Some Satoshis then, a lot of money for her today. So as long as I hodl, all is fine

But of course: I'm open to any kind of idea any of you has to make my setup more efficient!

(Btw: My cave is huge. I mean: HUGE. And in our town, the caves are spanning over a total of 14 kilometers. The mayor already announced that he'd like to see my setup. So in the best of all cases, we may turn into a little Bitcoin-mining-town)

The only way you could improve the efficiency of the water condensation is to increase the surface area of the copper collectors, or add to that since you have free electric is to get a heat exchanger to make sure the pipes are kept well below ambient temperature. Alternately air conditioning or proper de-humidifier.

[mikeywith]

I think they're blowing the warm humid air into cold copper tubes, so the humid air is then condensing in the copper tubing providing water drops. Not particularly efficient but assuming the copper tubes remain below ambient temperature they'll allow condensation to form.

It depends on the size and lenght of those copper tubes, plus how much heat is being pushed into them, as you know copper has one of the highest thermal conductivity properties, so it won't take much for the heat to reach the other side of the tubing, I can't imagine the entire setup but this may not work if the tubing is not long and large enough.

Also the pressure inside the tubes would help with condensing, so there are many factors to consider, this setup probably needs a professional person to set up perfectly.


@OP، i am interested in this, i love seeing different ideas, please keep updating, with pictures if possible. 

[RealMalatesta]

It depends on the size and lenght of those copper tubes, plus how much heat is being pushed into them, as you know copper has one of the highest thermal conductivity properties, so it won't take much for the heat to reach the other side of the tubing, I can't imagine the entire setup but this may not work if the tubing is not long and large enough.

Also the pressure inside the tubes would help with condensing, so there are many factors to consider, this setup probably needs a professional person to set up perfectly.

@OP، i am interested in this, i love seeing different ideas, please keep updating, with pictures if possible. 

I thought about using a pressure vessel (not sure about the english term, sorry...), but this would have been too much. Instead, I first direct the hot air into a "chamber" through which a copper tube is running; fresh, cold air is pumped through this coil permanently. This is the first station for condensation. Then the air is blown through 15 meters of a copper tube (which seems to be the best soluion here with 380 W/mK). The end of the tube leads upwards through a "chimney" which is covered on top again with a "hat" to gain any remains that could condensate.

It all may be an overkill for the few liters I can harvest, but if it works, I hope to be able to expand it.

After all, my calculations for the current setup show only a few liters per day, however, combined with the water from the heat pump, rain water and water from the dryer, it should be enough for a year.