Hello Mike, I do not know if someone answered already … If so here is another one.
Our experience was with equipment deployed at and near the South Pole. That environment differs from your situation in some ways, but it is similar in others. The biggest problem you will face is humidity and the second biggest is thermal cycling. The interior of Antarctica is very very dry. The typical outdoor humidity was about 5% to 10% max. Indoor humidity, and where people congregate, is higher. Our most significant problems occurred when cold equipment was brought in contact with warmer moist air. Frost would form and then as the equipment warmed up (or worse power on in that environment) the frost would melt and pow! (Think spraying mist all over powered equipment … not good! :-)) We developed a protocol where cold equipment, powered off, was put into a sealed plastic bag containing lots a desiccant. (BTW: When we ran low, dry rice worked reasonably well) . The bag was shaped to minimize the amount of air in trapped in the bag. The equipment was brought in and kept in the sealed bad until it was warm to the touch. Only then would we open the bag. Yes, frost formed on the outside of the bag, but inside with desiccant (lots of desiccant) it did not. The frost would melt as the bag warmed. We were careful to dry the outside of the bag before opening. Before returning to the outside, we would recharge the desiccant. We would squeeze the air out of the bags before going outside. The equipment was placed in a cooling box that was below freezing but not as cold as outside and where people did not spend a lot of time breathing moist air. The equipment would sit and acclimate before going all the way outside. The above takes time … a maddening amount of time to some … however everything takes much longer in Antarctica. Getting replacement equipment takes months so spending an hour in these warming / cooling stages is much better than having a failure due to contact with water. :-) Thermal cycling will take a toll on your equipment. So minimize the the number of time it will warm and cool. Leave the unit powered on as much of the time as possible when it is outside and cold. Don't bring the unit from the below-zero cooling chamber to the outside until you are ready to it plug it on and power it on. Use an SSD drive that is compatible with the Soekris instead of a hard drive. Most SSDs are better than hard drives in dealing with the cold. Eliminate unnecessary disk I/O. Mount your filesystems with the "noatime" option. Consider placing desiccant inside the box. Use desiccant that is in those little bags. Don't put so much as to impede the airflow / vent flow. There is spare room in our net5501 box so you should be able to attach some bags of desiccant into a corner that is not touching the electronics nor covering up air holes. Thermal cycling will be harsh on your plugs and connectors, particularly those next to warm devices such as drives. Consider wrapping electrical tape around the device and connector to pull the connector next to the SSD drive as much as possible. Consider buying more than one unit in case of a failure. Good luck! chongo (Landon Curt Noll) /\oo/\ _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
