5 ms·

Something that would help the risk of power outages killing air conditioning, would be to power air conditioning directly by solar panels installed alongside.

Something that would help the risk of power outages killing air conditioning, would be to power air conditioning directly by solar panels installed alongside. There is a high correlation between solar generation and air-con demand, although it's not perfect, as e.g. heat can persist into the evening, so you could have a grid connection to allow the air con to continue working in the evenings, and to absorb any excess power but in the event of grid failure, the air-con power should just follow the solar generation directly. I don't know if such a system exists commercially at the moment. Even in the event of wide scale power outages, it would not lead to wide scale deaths as most people would have air conditioning that still worked. Air conditioning failures would be a very serious issue, though, requiring evacuation to another building.

gnode 7y ago
This could help in some low density cases, but probably not in dense cities. It would require some changes to the inverters such that air con could still be powered in a blackout, due to anti-islanding concerns (feeding power into an isolated portion of the grid can cause injury to workers and further electrical faults). An easier alternative for these rare cases is probably just to have a backup diesel generator.
- rjmunro 7y ago
  Power outages are not rare everywhere. Where they are rare, a diesel generator that is hardly ever used is likely to not work the time you actually need it. When the grid is working, powering your A/C from solar is still a good idea, and returning power to the grid when you don't need the AC is often helpful. In terms of emergency power outage in hot day situations, you don't need to cool the whole building, or cool it to a comfortable temperature, it just needs to be below a "wetbulb" of 35°C in a single room people can shelter in until power is restored.
olivermarks 7y ago
You would need a huge number of solar panels and batteries to power an air conditioning unit. Dehumidifiers are far more energy efficient (removes the hot water droplets suspended in air to cool air temp)
- volkl48 7y ago
  > Dehumidifiers are far more energy efficient (removes the hot water droplets suspended in air to cool air temp) Do you have some sort of citation for that? Because a dehumidifier is pretty much an air conditioner that doesn't make the room cooler from a mechanical perspective, so the premise that there's a wide gap in efficiency, or that the unit which blows it's heat indoors is the more effective one, seems unlikely to me.
  - olivermarks 7y ago
    I was interested in off grid and RV vehicle AC solar, this video pretty much sums up how and where we are today on that. https://youtu.be/B0rZY5uotKI https://youtu.be/B0rZY5uotKI Others recommend dehumidifiers as a compromise which uses less power, you can find this in multiple discussions in relevant forums
  - undersuit 7y ago
    I guess running dehumidifiers allows the human body to cool itself when exposed to the environment referenced in the article. While comfort from an air-conditioned room would still be nice I'll take mild discomfort over hyperthermia any day.
- hollerith 7y ago
  >removes the hot water droplets suspended in air to cool air temp First of all, most of the water is in gaseous form, i.e., vapor, not droplets. But even if it were in the form of droplets, the droplets would have to be small enough to remain in the air, and consequently just like the water vapor, they'd be in thermal equilibrium with all the other molecules of air with the result that removing them would not lower air temperature.

gnode 7y ago

This could help in some low density cases, but probably not in dense cities. It would require some changes to the inverters such that air con could still be powered in a blackout, due to anti-islanding concerns (feeding power into an isolated portion of the grid can cause injury to workers and further electrical faults). An easier alternative for these rare cases is probably just to have a backup diesel generator.

rjmunro 7y ago
Power outages are not rare everywhere. Where they are rare, a diesel generator that is hardly ever used is likely to not work the time you actually need it. When the grid is working, powering your A/C from solar is still a good idea, and returning power to the grid when you don't need the AC is often helpful. In terms of emergency power outage in hot day situations, you don't need to cool the whole building, or cool it to a comfortable temperature, it just needs to be below a "wetbulb" of 35°C in a single room people can shelter in until power is restored.

olivermarks 7y ago

You would need a huge number of solar panels and batteries to power an air conditioning unit. Dehumidifiers are far more energy efficient (removes the hot water droplets suspended in air to cool air temp)

volkl48 7y ago
> Dehumidifiers are far more energy efficient (removes the hot water droplets suspended in air to cool air temp) Do you have some sort of citation for that? Because a dehumidifier is pretty much an air conditioner that doesn't make the room cooler from a mechanical perspective, so the premise that there's a wide gap in efficiency, or that the unit which blows it's heat indoors is the more effective one, seems unlikely to me.
- olivermarks 7y ago
  I was interested in off grid and RV vehicle AC solar, this video pretty much sums up how and where we are today on that. https://youtu.be/B0rZY5uotKI https://youtu.be/B0rZY5uotKI Others recommend dehumidifiers as a compromise which uses less power, you can find this in multiple discussions in relevant forums
- undersuit 7y ago
  I guess running dehumidifiers allows the human body to cool itself when exposed to the environment referenced in the article. While comfort from an air-conditioned room would still be nice I'll take mild discomfort over hyperthermia any day.
hollerith 7y ago
>removes the hot water droplets suspended in air to cool air temp First of all, most of the water is in gaseous form, i.e., vapor, not droplets. But even if it were in the form of droplets, the droplets would have to be small enough to remain in the air, and consequently just like the water vapor, they'd be in thermal equilibrium with all the other molecules of air with the result that removing them would not lower air temperature.