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In Nigeria, Solar-Powered Fridges at Outdoor Markets Save Food from Spoiling

58 points by curtis 11y ago

paulmd 11y ago
The text of the article mentions cold-rooms but the picture shows freestanding refrigerators. For small-scale storage they should should be using front-opening/chest-style refrigerators instead of freestanding ones. Since cold air is denser than warm air, it falls. That means that every time someone opens a freestanding fridge a significant amount of your cold air falls right out. Top-opening fridges provide a well that retains the cold, significantly reducing energy usage especially on fridges that are frequently opened. You see it a lot on freezers because the air is much colder and the cold tends to fall out even faster as a result. I think it would produce improvements here as well, since the energy produced by a solar panel is rather limited. Assuming you could protect the cooling system and provide sufficient airflow - could you operate a fridge flipped on its back? Or does the compressor depend on proper orientation to have gravity return coolant and so on?
- deleted 11y ago
  [deleted]
- ZeroGravitas 11y ago
  I've seen an article online where an "off-grid" home powered by solar re-purposes a chest freezer into a fridge for the very reason you state. http://newlifeonahomestead.com/convert-chest-freezer-to-fridge-solar/ http://newlifeonahomestead.com/convert-chest-freezer-to-frid...
Asbostos 11y ago
I wonder what the novel feature is here. Surely somebody would have thought of renting space in a solar powered fridge before? Maybe it's only recently become viable because of improvements in the economy?
- rmc 11y ago
  No wireless, less space than a Nomad. Lame.
- ZeroGravitas 11y ago
  The cost of solar panels (and batteries) has been dropping at a reasonable pace and is set to continue to do so for a while, so there's probably a whole bunch of "solar powered X" businesses that will become feasible as time goes on. There's some nice synergies here, you need the refrigeration most when the sun is shining brightest, a well insulated fridge acts as a kind of battery, the solar panels shade the fridge from the sun, and so on that are strangely pleasing to some aesthetic sense of mine.
lscharen 11y ago
Interesting that the article specifically mentions that the solar panels feed and inverter first, and then power the refrigerator. There are refrigerators designed to work directly off of 24V DC, which would seem to be a more logical choice. http://m.alibaba.com/showroom/24v-refrigerator-compressor.html http://m.alibaba.com/showroom/24v-refrigerator-compressor.ht... These are less common, though. Maybe cheaper commodity prices for AC-powered compressors offsets the additional inverter cost and efficiency losses?
- warfangle 11y ago
  You can cannibalize an AC compressor from a car. Alibaba has AC-compressors for as little as $1/pc. They are much cheaper, and much more common.
  - Johnythree 11y ago
    Most car A/C compressors are belt driven from the engine, eg no electric motor so not much use for Solar operation.
    - warfangle 11y ago
      That's a good point - I didn't realize that. Still easy to cannibalize if you have an AC motor :)
1ris 11y ago
Are batteries involved? Or is the insulation simply thick enough the keep the food cold enough during nighttime?
- gambiting 11y ago
  Bear in mind that in many "hot" places the temperature during the night falls down to nearly 0C, so it's probably enough to stop the food from spoiling.

58 points by curtis 11y ago

The text of the article mentions cold-rooms but the picture shows freestanding refrigerators. For small-scale storage they should should be using front-opening/chest-style refrigerators instead of freestanding ones. Since cold air is denser than warm air, it falls. That means that every time someone opens a freestanding fridge a significant amount of your cold air falls right out. Top-opening fridges provide a well that retains the cold, significantly reducing energy usage especially on fridges that are frequently opened. You see it a lot on freezers because the air is much colder and the cold tends to fall out even faster as a result. I think it would produce improvements here as well, since the energy produced by a solar panel is rather limited. Assuming you could protect the cooling system and provide sufficient airflow - could you operate a fridge flipped on its back? Or does the compressor depend on proper orientation to have gravity return coolant and so on?

deleted 11y ago
[deleted]
ZeroGravitas 11y ago
I've seen an article online where an "off-grid" home powered by solar re-purposes a chest freezer into a fridge for the very reason you state. http://newlifeonahomestead.com/convert-chest-freezer-to-fridge-solar/ http://newlifeonahomestead.com/convert-chest-freezer-to-frid...

Asbostos 11y ago

I wonder what the novel feature is here. Surely somebody would have thought of renting space in a solar powered fridge before? Maybe it's only recently become viable because of improvements in the economy?

rmc 11y ago
No wireless, less space than a Nomad. Lame.
ZeroGravitas 11y ago
The cost of solar panels (and batteries) has been dropping at a reasonable pace and is set to continue to do so for a while, so there's probably a whole bunch of "solar powered X" businesses that will become feasible as time goes on. There's some nice synergies here, you need the refrigeration most when the sun is shining brightest, a well insulated fridge acts as a kind of battery, the solar panels shade the fridge from the sun, and so on that are strangely pleasing to some aesthetic sense of mine.

lscharen 11y ago

Interesting that the article specifically mentions that the solar panels feed and inverter first, and then power the refrigerator. There are refrigerators designed to work directly off of 24V DC, which would seem to be a more logical choice. http://m.alibaba.com/showroom/24v-refrigerator-compressor.html http://m.alibaba.com/showroom/24v-refrigerator-compressor.ht... These are less common, though. Maybe cheaper commodity prices for AC-powered compressors offsets the additional inverter cost and efficiency losses?

warfangle 11y ago
You can cannibalize an AC compressor from a car. Alibaba has AC-compressors for as little as $1/pc. They are much cheaper, and much more common.
- Johnythree 11y ago
  Most car A/C compressors are belt driven from the engine, eg no electric motor so not much use for Solar operation.
  - warfangle 11y ago
    That's a good point - I didn't realize that. Still easy to cannibalize if you have an AC motor :)

1ris 11y ago

Are batteries involved? Or is the insulation simply thick enough the keep the food cold enough during nighttime?

gambiting 11y ago
Bear in mind that in many "hot" places the temperature during the night falls down to nearly 0C, so it's probably enough to stop the food from spoiling.