Preventing rust on the Antminer S9

[Sandal_Hat]

Those deciccents are far weaker than dehumidifiers and u have to get rid of the moisture they absorb by heating them later on. The moisture is released in the air when u heat them.

Yes they are not as effective as a dehumidifier, but OP did not feel a dehumidifier was the best for their setup.

The idea of the moisture being released into the air is the point I brough tup about "regenerating" the desiccant. When it becomes saturated you would move it to the "hot" side of the farm. Using the discharge air to remove moisture along with the heat. So the practicwe would be to have 2 or 3 sets of desiccant that can be swapped out as needed. This provides for a continuous cycle with no extra power consumption.

It's just an idea, I haven't needed it because I do not deal with that level of humidity.

You do NOT have to run your entire inlet airstream THROUGH a dehumidifier for it to be effective - just have it AT the intake area to soak up enough of the humidity to reduce it enough to keep stuff from rusting.

This is an excellent point.

If I recall right, desicants are incredibly weak compared to a dehumidifier. U need a hell lot of space and alot of them before it even has any effect on this kinda airflow. Dehumidifier will heat up the air. Air con that dehumidifies is best but is costly and only gives so much airflow as well. U gotta also watch out for condensation risks.

[tim-bc]

You do NOT have to run your entire inlet airstream THROUGH a dehumidifier for it to be effective - just have it AT the intake area to soak up enough of the humidity to reduce it enough to keep stuff from rusting.

Unfortunately there's no one intake area / airstream. Air just floats in passively through sheets of fine mesh (>500 m^2).

Yes they are not as effective as a dehumidifier, but OP did not feel a dehumidifier was the best for their setup.

It's just too expensive. Even industrial dehumidifiers can't process 1 m^3/s, there would need to be dozens of them just to reduce humidity by 1-2%!

[QuintLeo]

If I recall right, desicants are incredibly weak compared to a dehumidifier. U need a hell lot of space and alot of them before it even has any effect on this kinda airflow. Dehumidifier will heat up the air. Air con that dehumidifies is best but is costly and only gives so much airflow as well. U gotta also watch out for condensation risks.

Desiccants are only viable in small ENCLOSED spaces, they do not soak much moisture from the air at all per unit of weight/volume.
Dehumidifiers do NOT heat up the air, every "mechanical" dehumidifier setup I've EVER seen was a specialized air conditioner and the air they put out of the "dehumidified" side was COOL to COLD.
There is NO condensation risk on the air out of the dehumidifier, there's pretty close to no moisture in there that CAN condense.

It won't take "dozens" of them to reduce humidity 1-2%, unless you are running MILLIONS of CFM airflow (hundreds of thousands of M^3/minute) and have 80%+ humidity air input - though it would get complicated a bit by the fact they would reduce your intake air temp some, they'd still be pulling SOME of the water out of the air so even if the RH didn't drop a lot the moisture content of the air WOULD which should reduce the rust issue.


Moderator's note: This post was edited by frodocooper to remove multiple nested quotes.

[tim-bc]

It won't take "dozens" of them to reduce humidity 1-2%, unless you are running MILLIONS of CFM airflow (hundreds of thousands of M^3/minute) and have 80%+ humidity air input - though it would get complicated a bit by the fact they would reduce your intake air temp some, they'd still be pulling SOME of the water out of the air so even if the RH didn't drop a lot the moisture content of the air WOULD which should reduce the rust issue.

Airflow is in the millions CFM. I was using m^3/s not m^3/min. Also, the humidity is often above 80%. I get that dehumidifiers would still have an effect even with these conditions but I don't think that effect is worth the expensive price tag.

[QuintLeo]

I saw the comment about 1 m^3/sec but thought it was a typo as it's not a normal specification - airflows are normally specified in m^3/min or CFM depending on if you're in a metric area or not.

How bloody big of a farm are you running to need airflow in the millions of CFM?

I'm also curious about where, as I don't know of any area that is close enough to an ocean or a large salt lake to have significant salt water in the air that also has access to low cost electric.

[Sandal_Hat]

Desiccants are only viable in small ENCLOSED spaces, they do not soak much moisture from the air at all per unit of weight/volume.
Dehumidifiers do NOT heat up the air, every "mechanical" dehumidifier setup I've EVER seen was a specialized air conditioner and the air they put out of the "dehumidified" side was COOL to COLD.
There is NO condensation risk on the air out of the dehumidifier, there's pretty close to no moisture in there that CAN condense.

It won't take "dozens" of them to reduce humidity 1-2%, unless you are running MILLIONS of CFM airflow (hundreds of thousands of M^3/minute) and have 80%+ humidity air input - though it would get complicated a bit by the fact they would reduce your intake air temp some, they'd still be pulling SOME of the water out of the air so even if the RH didn't drop a lot the moisture content of the air WOULD which should reduce the rust issue.

Yep, desiccants are too weak.

Dehumidifiers do heat up the air. Do google it. It heats up the air to remove moisture. Hotter air cannot hold as much moisture as colder air. Thus, moisture is removed when air is heated.

Airflow is usually in the few hundreds per cfm. I think a typhoon is millions of cfm
A strong dehumidifier can do a few hundreds per cfm at most though. A smaller fan would remove air faster.


Moderator's note: This post was edited by frodocooper to remove multiple nested quotes.

[Steamtyme]

Yep, desiccants are too weak.

Dehumidifiers do heat up the air. Do google it. It heats up the air to remove moisture. Hotter air cannot hold as much moisture as colder air. Thus, moisture is removed when air is heated.

Airflow is usually in the few hundreds per cfm. I think a typhoon is millions of cfm
A strong dehumidifier can do a few hundreds per cfm at most though. A smaller fan would remove air faster.

You are mistaken on how dehumidification works.

Hot warm air holds more moisture. As the air cools down moisture is released.

If you have been googling dehumidifer for industrial purposes. They pump hot air into a space and then exhaust it to take the moisture out of the plant. I work in a food processing plant and this is done at cleanup so the floor is dry and ready for production in the morning.

All this being said refrigeration or air conditioning dehumidify a space as well. Again by lowering the temperatures. That's why most portable home AC units have a drain on them.

@tim
I've been looking through different options for you because your setup does sound quite large. I don't know what your budget is or anything but I'll pass along ideas I think could work.

Are you opposed to running a cold water line "coil" in some ducting? If you do this at an airflow change in direction with a drain at the base it might knock enough moisture out of the air for you. This is really only a good option if your site has a certain level of water consumption already. Or you are willing to invest in pumps compressors and fans, this is then a refrigeration/ac system

Edited: sorry was on my phone forgot the blue bit

[Sandal_Hat]

You are mistaken on how dehumidification works.

Hot warm air holds more moisture. As the air cools down moisture is released.

If you have been googling dehumidifier for industrial purposes. They pump hot air into a space and then exhaust it to take the moisture out of the plant. I work in a food processing plant and this is done at cleanup so the floor is dry and ready for production in the morning.

All this being said refrigeration or air conditioning dehumidifier a space as well. Again by lowering the temperatures. That's why most portable home AC units have a drain on them.

[...]

Oh yep, u are right. Hot air holds more moisture, not the other way around. It cools the air first to drain the moisture, and then it reheats the air.


Moderator's note: This post was edited by frodocooper to trim the quote from Steamtyme.

[QuintLeo]

Are you opposed to running a cold water line "coil" in some ducting? If you do this at an airflow change with a drain at the base it might knock enough moisture out of the air for you. This is really only a good option if your site has a certain level of water consumption already. Or you are willing to invest in pumps compressors and fans, this is then a refrigeration/ac system

Or perhaps a geothermal loop to cool the water before it goes into that "coil".

[Steamtyme]

Or perhaps a geothermal loop to cool the water before it goes into that "coil".

That's a great idea you could then get away with using a water reservoir and a small circulating pump.

Let us know what you come up with Tim. Good luck with the farm

[tim-bc]

I'm also curious about where, as I don't know of any area that is close enough to an ocean or a large salt lake to have significant salt water in the air that also has access to low cost electric.

These miners are in the west, in the Americas. The airflow is higher than it typically might be because fans are either running full pwm or have upgraded / additional fans in the stream to provide even more airflow (because of the heat).

using a water reservoir and a small circulating pump.

It would be great to be able to pump water like you suggested in order to address both the heat and the humidity at the same time. Hopefully things will work out before everything gets hot again.

[QuintLeo]

I'm also curious about where, as I don't know of any area that is close enough to an ocean or a large salt lake to have significant salt water in the air that also has access to low cost electric.

These miners are in the west, in the Americas. The airflow is higher than it typically might be because fans are either running full pwm or have upgraded / additional fans in the stream to provide even more airflow (because of the heat).

 *I* am "in the west, in the Americas" but there's no salt water within 100 miles of me and no issue with salt in the air anywhere in the area of very low cost electric I'm in.