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Japanese Farmer Builds High-Tech Indoor Veggie Factory

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Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#41

Post by Retric »

idibidiart wrote: post #40
Retric wrote: post #39

Earlier quoted context omitted.

Numbers matter. 45% of the light is in the photosynthetic active wavelength range in a normal farm vs ~20% solar panels w/ transmission conversion losses etc + 40% LED = ~8% of the incoming light is now useful for photosynthesis. So, you need a huge increase in efficiency ~400+% just to break even. PS: Not that their using solar power, but it's still worth considering.

What does the 45% of light that is in the photosynthetic range have to do with the with the efficiency of solar cells and LEDs? It would be more direct to compare % of natural light that is in photosynthetic range with % of LED light that is in that range. If you have a formula on which you're basing your assumptions then write it down so I can understand and examine your logic without any misunderstanding. Else, you…

Ideally 100% of LED light is in the photosynthetic rage. It looks like there using white LED's which are less efficient AND not optimal for plants. Sill, assuming the 'best case' using current mass market tech.

  Sunlight > photosynthisis (45%)   = 45%.
  Sunlight > solar cell (22%) > conversion, storage, transmission (90%) 
  > LED (40%) > photosynthisis(100%) = 8%
reality is LED efficecy drops over time and LED light is not quite 100% ect but this is the optomistic best case numbers.

Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#42

Post by Shivetya »

idibidiart wrote: post #36

Hand wavy arguments as to why this is a bad idea are ... well, just hand wavy. Solar is ~20% efficient LED's are less than ~40% efficient so you would need more land area for solar farms than you save by growing indoors. On top of that you need to pay for all your capital costs. There are other issues, but if this was close to cost effective you would be seeing this in Iceland which gets little sunlight in the winter…

well normally farms cannot grow up, skyscraper style. Also, situating the building properly should allow for some of it to also be used for power generation. Then lets go further, make it tall enough that the warm air rising from the bottom could be used to generate power.

Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#43

Post by idibidiart »

Shivetya wrote: post #42
idibidiart wrote: post #36

Hand wavy arguments as to why this is a bad idea are ... well, just hand wavy. Solar is ~20% efficient LED's are less than ~40% efficient so you would need more land area for solar farms than you save by growing indoors. On top of that you need to pay for all your capital costs. There are other issues, but if this was close to cost effective you would be seeing this in Iceland which gets little sunlight in the winter…

well normally farms cannot grow up, skyscraper style. Also, situating the building properly should allow for some of it to also be used for power generation. Then lets go further, make it tall enough that the warm air rising from the bottom could be used to generate power.

right, that's the point of stacking and other structure-wise efficiency enhancement... I didn't go as far as the warm air rising =)

Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#44

Post by idibidiart »

Retric wrote: post #41
idibidiart wrote: post #40

Earlier quoted context omitted.

What does the 45% of light that is in the photosynthetic range have to do with the with the efficiency of solar cells and LEDs? It would be more direct to compare % of natural light that is in photosynthetic range with % of LED light that is in that range. If you have a formula on which you're basing your assumptions then write it down so I can understand and examine your logic without any misunderstanding. Else, you…

Ideally 100% of LED light is in the photosynthetic rage. It looks like there using white LED's which are less efficient AND not optimal for plants. Sill, assuming the 'best case' using current mass market tech. Sunlight > photosynthisis (45%) = 45%. Sunlight > solar cell (22%) > conversion, storage, transmission (90%) > LED (40%) > photosynthisis(100%) = 8% reality is LED efficecy drops over time and LED light is not…

but what stops a structural technique for maximizing light usage by plants (like stacking or some more optimal structural pattern, such as the natural tree pattern [1] optimized by nature) from achieving 4X or more increase in efficiency of light usage?

1. http://online.wsj.com/news/articles/SB1000142405297020355030...

Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#45

Post by idibidiart »

idibidiart wrote: post #43
Shivetya wrote: post #42

Earlier quoted context omitted.

well normally farms cannot grow up, skyscraper style. Also, situating the building properly should allow for some of it to also be used for power generation. Then lets go further, make it tall enough that the warm air rising from the bottom could be used to generate power.

right, that's the point of stacking and other structure-wise efficiency enhancement... I didn't go as far as the warm air rising =)

see this other structural pattern for maximizing use of available light (be it LED light or sun light)

http://online.wsj.com/news/articles/SB1000142405297020355030...

Re: Japanese Farmer Builds High-Tech Indoor Veggie Factory

#46

Post by Retric »

idibidiart wrote: post #44
Retric wrote: post #41

Earlier quoted context omitted.

Ideally 100% of LED light is in the photosynthetic rage. It looks like there using white LED's which are less efficient AND not optimal for plants. Sill, assuming the 'best case' using current mass market tech. Sunlight > photosynthisis (45%) = 45%. Sunlight > solar cell (22%) > conversion, storage, transmission (90%) > LED (40%) > photosynthisis(100%) = 8% reality is LED efficecy drops over time and LED light is not…

but what stops a structural technique for maximizing light usage by plants (like stacking or some more optimal structural pattern, such as the natural tree pattern [1] optimized by nature) from achieving 4X or more increase in efficiency of light usage? 1. http://online.wsj.com/news/articles/SB1000142405297020355030...

You can do the same sort of 3D arrangements with plants and sunlight. However, building a 3d structure costs money so you need to compare it with all the other ways of boosting yeild to find out the best option.

Generally, a mix of irrigation, fertilizer, better breeds, and greenhouses are the best option for boosting yield. Mix in more marginal land as needed (Note: ~68.4% of Japan is covered in forests.)

Greenhouses for example let you have a longer growing season and pack plants more closely together when their young. Which can let you have an early harvest and then use that same land for another plant or a plant with a longer growing season. Closer to the tropics you can often get 2 or 3 harvests a year. However, they have significant capital and labor costs.

PS: Now, we can try and figure out how a Dystopian future can feed say X billion people but we are a long way from needing indoor hydroponics.

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