3 ms·

That would be a massive amount of solar, if a tent AC has 7kw and a standard panel has 180w theoretical output.

londons_explore 5y ago
A standard 2x1m panel now has an output of more like 450-500 watts. Technology has moved on since the days of 9% efficient panels!
- bborud 5y ago
  So if we assume the sun was shining whenever the AC needs to draw 7kW, that would mean roughly 30m^2 of solar panels per 7kW AC. So roughly one (american) football field of solar panels for every 180 or so 7kW AC units. (Rounding generously since this is just a thought experiment to look at some lower bounds.You'd probably need a lot more solar panels than that (3x?), plus battery infrastructure, plus some way of cleaning the panels etc. for this to be practical)
  - londons_explore 5y ago
    If you actually wanted to solar power the military, you'd design stuff the be energy efficient from the start. That would probably consist of all buildings having 3 inches of insulation on all sides so that you need far less cooling. Then you have the solar cells built into the roof, and the batteries built in too, so the whole unit is "dump this anywhere in the world and it makes habitable space". Grid connection optional - and if provided can be used to automatically balance electrical load between buildings. This probably weighs less than a tent plus generator plus fuel.
    - nradov 5y ago
      It's not practical to build insulated buildings at forward operating bases. They don't have the time, materials, or equipment. Everything has to be flown in by helicopter, or transported in truck convoys over terrible roads under constant threat of roadside bombs. Tents are light and can be erected in minutes.
      - matthewdgreen 5y ago
        "The Army has a $95 million contract to foam up to nine million square feet of building space in Iraq, of which about 60 percent has been completed. The Army also let a $29 million contract to foam structures in Afghanistan. So far, 150,000 square feet have been foamed. It takes a mere 26 days to recoup the costs of the foaming through the fuel savings." https://www.army.mil/article/20777/army_saves_fuel_and_lives_by_bringing_new_life_to_an_old_technology https://www.army.mil/article/20777/army_saves_fuel_and_lives...
    - bborud 5y ago
      Have you taken some time to consider why forward operating bases make use of tents rather than what, for all practical purposes, would be houses?
    - Gravityloss 5y ago
      Even just putting two tents on top of each other already improves the insulation a lot, because of the air layer. This was used already during the second world war over here. In reality in general it's hard to do things that make sense as a whole - large organizations can only optimize invididual parts.

A standard 2x1m panel now has an output of more like 450-500 watts. Technology has moved on since the days of 9% efficient panels!

bborud 5y ago
So if we assume the sun was shining whenever the AC needs to draw 7kW, that would mean roughly 30m^2 of solar panels per 7kW AC. So roughly one (american) football field of solar panels for every 180 or so 7kW AC units. (Rounding generously since this is just a thought experiment to look at some lower bounds.You'd probably need a lot more solar panels than that (3x?), plus battery infrastructure, plus some way of cleaning the panels etc. for this to be practical)
- londons_explore 5y ago
  If you actually wanted to solar power the military, you'd design stuff the be energy efficient from the start. That would probably consist of all buildings having 3 inches of insulation on all sides so that you need far less cooling. Then you have the solar cells built into the roof, and the batteries built in too, so the whole unit is "dump this anywhere in the world and it makes habitable space". Grid connection optional - and if provided can be used to automatically balance electrical load between buildings. This probably weighs less than a tent plus generator plus fuel.
  - nradov 5y ago
    It's not practical to build insulated buildings at forward operating bases. They don't have the time, materials, or equipment. Everything has to be flown in by helicopter, or transported in truck convoys over terrible roads under constant threat of roadside bombs. Tents are light and can be erected in minutes.
    - matthewdgreen 5y ago
      "The Army has a $95 million contract to foam up to nine million square feet of building space in Iraq, of which about 60 percent has been completed. The Army also let a $29 million contract to foam structures in Afghanistan. So far, 150,000 square feet have been foamed. It takes a mere 26 days to recoup the costs of the foaming through the fuel savings." https://www.army.mil/article/20777/army_saves_fuel_and_lives_by_bringing_new_life_to_an_old_technology https://www.army.mil/article/20777/army_saves_fuel_and_lives...
  - bborud 5y ago
    Have you taken some time to consider why forward operating bases make use of tents rather than what, for all practical purposes, would be houses?
  - Gravityloss 5y ago
    Even just putting two tents on top of each other already improves the insulation a lot, because of the air layer. This was used already during the second world war over here. In reality in general it's hard to do things that make sense as a whole - large organizations can only optimize invididual parts.