LED-lit urban farms

 

LED-lit urban farms aim to transform blighted cities with jobs, fresh food article tells about an interesting application for LEDs: A group of high-tech urban pioneers is using LEDs to power a large indoor vertical farming system in Newark, NJ. When complete, AeroFarms‘ latest urban agriculture system is expected to enough produce pesticide-free greens and herbs to feed over 50,000 people while using 3% of the space required by conventional dirt farming.

The so-called “Aeroponic system is a type of hydroponic technology that grows plants in a mist. The seeds are embedded within a cloth medium where they are germinated and exposed to with LEDs which emit specific wavelengths of light for more efficient photosynthesis and less energy consumption.

What types of LEDs are needed for urban agriculture system? A grow light or plant light is an artificial light source, generally an electric light, designed to stimulate plant growth by emitting an electromagnetic spectrum appropriate for photosynthesis. Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated.

Plants do not effectively use the entire spectrum of light. LEDs allow production of bright and long-lasting grow lights that emit only the wavelengths of light corresponding to the absorption peaks of a plant’s typical photochemical processes. There are multiple absorption peaks for chlorophyll and carotenoids, and LED grow-lights may use one or more LED colors overlapping these peaks. Here is graph from EarthLED GrowLED™ Series LED Grow Lights page:

Often blue LEDs are preferred, where the light has a wavelength in the mid-400 nm range (blue). For growing fruits or flowers, a greater proportion of red LEDs is considered preferable, with light very near 600-640 nm(red). So you can make greenhouses glow with blue and red. LEDs can be easily adjusted. By varying the output power of individual colors, the grower can simulate seasonal light changes over a multi-week growing cycle: more blue light mimics the summer sun (vegetative phase), and more red light simulates the sunlight in the fall (flowering phase).

Research is rapidly advancing in the horticulture industry that indicates LED-based solid-state lighting (SSL) might boost productivity in greenhouse and plant-factory operations and reduce energy consumption.  More and more, plant scientists are integrating LEDs into their research programs to meet their needs for a specific light spectrum and to reduce the operational cost of their controlled growth environments.

 

12 Comments

  1. Tomi Engdahl says:

    What you don’t know about LED light intensity curves for grow light apps
    http://www.edn.com/design/led/4441872/What-you-don-t-know-about-LED-light-intensity-curves-for-grow-light-apps?_mc=NL_EDN_EDT_EDN_weekly_20160421&cid=NL_EDN_EDT_EDN_weekly_20160421&elqTrackId=b7187e473a4a42b2a513a7132d4ad0be&elq=b4d8dcae3c0c4e21972fab0e42ae186d&elqaid=31955&elqat=1&elqCampaignId=27871

    The light intensity curves for LEDs, regardless of whether they are collimated with a lens or reflectors, follow a bell shaped curve (often referred to as a “Lambertian“ curve). The 50% intensity point for an LED with no optic (bare LED) is virtually always at approximately 120 degrees (60 degrees in each direction).

    The 50% point (known as the “beam angle” or “viewing angle”) is a lesser number of degrees depending on the collimating specification used. The beam angle is the total angle in both plus and minus directions.

    What is not commonly known by those not experienced in the physics of LED light emission and optics is that the Lambertian LED light intensity curves can be very misleading in terms of how much light is actually arriving at the receiving end.

    Reply
  2. Tomi Engdahl says:

    Home Lumileds helps developers of horticultural LED luminaires dial in light recipes
    Lumileds helps developers of horticultural LED luminaires dial in light recipes
    http://www.ledsmagazine.com/articles/2017/01/lumileds-helps-developers-of-horticultural-led-luminaires-dial-in-light-recipes.html?cmpid=enl_leds_ledsmagazine_2017-01-18

    Packaged LED manufacturer Lumileds has announced a Horticulture Lighting Calculator intended to help solid-state lighting (SSL) product developers through the process of mixing different colors of LEDs in pursuit of optimum plant recipes for plants. The online calculator is preloaded with the operational characteristics of the Luxeon SunPlus families of packaged LEDs that the company announced back in September 2016. Prospective developers can specify mixes of members of the SunPlus families and immediately calculate the system-level output of a luminaire in terms of horticultural-specific metrics such as photosynthetic photon flux as well as the full spectral power distribution (SPD) of the design.

    Reply
  3. Tomi Engdahl says:

    Horticultural Lighting
    Brought to you by LEDs Magazine and
    http://www.ledsmagazine.com/horticulture.html?cmpid=enl_leds_ledsmagazine_2017-01-18

    Horticultural lighting is the LED industry’s most explosive new market, revolutionizing the future of farming with technologies and innovations enabling year-round sustainable fruit, vegetable and flower cultivation.

    Reply
  4. Tomi Engdahl says:

    Indoor farming with LEDs
    http://www.edn.com/electronics-blogs/led-zone/4443290/Indoor-farming-with-LEDs

    Agri-technology company Agrivolution recently announced that its LEDs were chosen for integration into the aeroponic vertical farming systems of Indoor Farms of America. The selection process involved a year-long evaluation of LEDs specifically used for agriculture.

    I love reading about applications that have real social benefit and this makes the list. The goal is to grow pesticide-free fruits and vegetables all year, a concept that has so far taken off in Asia more than in the U.S. The LEDs selected were the ultra-thin, lightweight triple-band bar-type LEDs. The LEDs feature a single-chip design that emits red, blue, and green bands covering full photosynthetically active radiation (PAR) between 400 and 700 nm. The LEDs output a balanced full-spectrum light while reducing energy usage.

    The lighting has been shown to grow larger heirloom tomatoes, squash, and cucumber and testing of additional crops continues. What’s important about this application is that, given the weather inconsistencies of the past several years, it is difficult to achieve steady and reliable food production in North America. In general, LEDs are less costly than alternative lighting methods, especially the newer LED grow lights. They produce less heat allowing them to be placed closer to the plants without burning them, and they also lower electricity costs.

    Reply
  5. Tomi Engdahl says:

    Horticulture – Home Specialty SSL Science advances in matching LED lighting to horticultural needs (MAGAZINE)
    Science advances in matching LED lighting to horticultural needs (MAGAZINE)
    http://www.ledsmagazine.com/horticulture/articles/science-advances-in-matching-led-lighting-to-horticultural-needs.html?cmpid=enl_leds_horticulturallightingnewsletter_2017-02-06

    LED-based SSL products are bringing revolutionary advancement to indoor and greenhouse growing operations, explains MAURY WRIGHT, but there remains much to be learned about the differing light needs of varying plant types and even how needs change during a growth cycle.

    High-power LEDs are bringing similar revolutionary benefits in life-science applications such as horticulture that the solid-state lighting (SSL) sources are offering in the general illumination area -energy efficiency, low/no maintenance, spectral control, and beam control. But plants need different things from light relative to people, and human-oriented metrics such as efficacy (lumens per watt – lm/W) or CRI may or may not provide any indication as to whether an LED luminaire will deliver results for vegetable and flower growers. Moreover, plants have circadian cycles that differ from those of humans and that vary widely from plant species to species. Still, growers are quickly moving to SSL in greenhouses and especially in indoor urban or vertical farms while the horticultural community is working overtime to decipher the needs of plants in terms of light recipes for optimal growth and yield.

    SSL could truly revolutionize the global horticulture industry including edible produce and the similar floriculture or flower-centric industry. LED-based lighting will also play a critical role in cannabis growing, especially as the legal climate evolves for both medical and/or recreational marijuana usage.

    SSL roles in horticulture

    The use case for LEDs in fruit and vegetable farming centers around extending the growing season, especially in cold regions with short summers. Artificial lighting, primarily high-pressure sodium (HPS) lighting in the past, has long been used in greenhouses to extend tomato seasons, for example. We will discuss what LED lighting adds to the story throughout this article, but one clear advantage of SSL is the fact that the lighting produces no heat and growers can use interlighting – placing lights near/between the plants, run either vertically or horizontally to deliver light to the lower foliage that doesn’t receive much direct light from above as the plant grows.

    The greenhouse use case for LEDs is primarily as a supplementary light source to the sun, although the artificial lighting is increasingly vital during the colder and shorter days of winter.

    Urban farms

    Indeed, it is perhaps the urban farms where LED lighting may have the largest impact on horticulture, and it wouldn’t be a huge stretch to say that impact extends to global society and the environment. The ability of growers to operate in high-volume vertical farms in any city means that the transportation cost will be slashed relative to the cost associated with farming in remote areas such as California’s Central Valley. Consumers will get access to produce in some cases the day it’s harvested and the product will have a far greater shelf life. And there will be immeasurable reductions in the carbon footprint associated with farming, both due to short transport and elimination of carbon-producing outdoor machinery needed for traditional farming.

    The growing methodology is extremely water efficient

    Challenges in horticultural lighting

    There are, of course, challenges in any emerging technology and perhaps even more so in LED-based horticultural lighting where experience with SSL technology is still shallow, and even the long-involved horticultural scientists are still developing research on light recipes for plants – and some of those new recipes weren’t feasible prior to LED sources with controlled spectrum entering the picture.

    That early research resulted in the plethora of fixtures on the market that emit pink or purplish light based on the use of monochromatic red and blue LEDs. The pervasive theory behind those products centered on energy efficiency and this question: Why should luminaire designs generate energy outside those bands if that energy would simply be wasted on the plant?

    Current thinking, however, centers on lighting that can deliver peak energy in the blue and red spectrum but that also delivers a broad spectrum much like sunlight. Paul Scheidt, LED product development leader at Cree, said, “The industry seems to be moving more to white light.”

    White light matters

    Yorio’s point is that research shows we can impact plant height and flowering by changing the spectrum.

    Vardi of Spectrum King said the predominant red and blue mix might work relatively well for leafy greens such as lettuces. But he also said flowering plants where biomass is the goal, including tomatoes and cannabis among others, require intensity more than specialized spectrum. Vardi said 90% of the energy in HPS lights is in the yellow region, and that lumens (lm), lux (lx) and efficacy may be more accurate than PAR-centric metrics in horticultural luminaires for flowering plants. Spectrum King uses 90% phosphor-converted white LEDs in its luminaires with the remainder being red or far-red LEDs. Vardi said the blue emitters that are the basis for white LEDs deliver all of the blue energy required for optimal production.

    Even in vertical farms where the focus is products like lettuce, it appears that some white light is a requisite, although you can see via photos in this article that the bulk of the LED light produced remains pink to purple in nature.

    White light can be important for reasons beyond baseline production in leafy greens. Several people we interviewed for this article said lettuce may not mature to look green without some light from the green spectral band.

    Clearly, there is no consensus on light recipes, and researchers and growers are constantly striving to advance the science.

    What growers want

    As the commercial LED-lit horticultural installations mature, there will be more certainty about what growers want from SSL manufacturers, although today that topic remains a bit of a mystery.

    First, Colangelo wants quality products that maximize the ratio of dollar per joule (a unit of energy or work done) per μmole.
    Second, he wants a lighting product that enables the farm to use a different light mix for each cultivar.
    Third, he cited ease of installation
    Fourth, Colangelo cited affordability and financing as important because he said lights are the most expensive element in a vertical farm.

    Not all commercial growers have found what they need from commercial LED lighting manufacturers. Local Roots, for example, has designed and begun to manufacture a custom LED luminaire in a rectangular form factor for its operations.

    LEDs enable vertical farming

    Still, it’s the LED technology that has truly made vertical farming pay off. Colangelo of Green Sense said LED lights enabled the vertical concept to go from pilot to commercial. He said growers could go from seven to eight layers with linear fluorescent lighting to 12 to 14 layers with LEDs in a building with, say, 25-ft-high ceilings. LED efficiency and the lack of radiated heat were the key enablers.

    Horticultural revolution

    Ultimately, LED lighting is poised to revolutionize all types of horticulture.

    Reply
  6. Tomi Engdahl says:

    Science advances in matching LED lighting to horticultural needs (MAGAZINE)
    http://www.ledsmagazine.com/horticulture/articles/science-advances-in-matching-led-lighting-to-horticultural-needs.html?cmpid=enl_leds_horticulturallightingnewsletter_2017-07-03

    LED-based SSL products are bringing revolutionary advancement to indoor and greenhouse growing operations, explains MAURY WRIGHT, but there remains much to be learned about the differing light needs of varying plant types and even how needs change during a growth cycle.

    High-power LEDs are bringing similar revolutionary benefits in life-science applications such as horticulture that the solid-state lighting (SSL) sources are offering in the general illumination area -energy efficiency, low/no maintenance, spectral control, and beam control. But plants need different things from light relative to people, and human-oriented metrics such as efficacy (lumens per watt – lm/W) or CRI may or may not provide any indication as to whether an LED luminaire will deliver results for vegetable and flower growers. Moreover, plants have circadian cycles that differ from those of humans and that vary widely from plant species to species. Still, growers are quickly moving to SSL in greenhouses and especially in indoor urban or vertical farms while the horticultural community is working overtime to decipher the needs of plants in terms of light recipes for optimal growth and yield.

    Reply
  7. Tomi Engdahl says:

    LED invention is revolutionizing the cleaning of bakery industry furnaces

    Led Tailor, a lighting technology specialty company, Led Tailor, has developed a method for purifying the oven used in the bakery industry by means of blue light. The company has applied for a patent for the world’s first self-inflicted and completely without external heat-generating kiln. The new PiTKO lifting oven will be announced at Leipuripäivät in Tampere on Saturday, August 12.

    One of the biggest problems in the bakery industry is to maintain the cleanliness of the floating kilns as the conditions prevailing within the furnace are very favorable for the growth of microbes, molds and bacteria. In the industry, large quantities of ingredients have to be thrown away due to pollution. At the same time, the means for controlling microbial contamination have become increasingly difficult.

    Mounting furnaces have not previously been installed in light-based photon disinfection systems. Thanks to the new method, baking baked pastries can be raised much faster than usual without an external heat source and with a more even finish. Additionally, the new PiTKO lifting furnace has a disinfecting program to clean the inside of the furnace from harmful microbes.

    - Blue light can control the microbes in controlled amounts, so their metabolism accelerates. For baked yeast this means that the yeast produces more dense carbon dioxide in the energy metabolism. At the same time, it is possible to produce higher quality and, above all, safer foods, “says Maria Leino, expert in microbiological testing at Led Tailor.

    Source: http://www.salonjokilaakso.net/salolaiskeksinto-mullistamassa-leipomoteollisuuden-uunien-puhdistuksen/

    Reply
  8. Tomi Engdahl says:

    Russian project is ‘largest horticultural LED job in history’
    http://luxreview.com/article/2017/09/russian-project-is-largest-horticultural-led-project-in-history-

    A MASSIVE installation of LED lighting designed to boost food supply in Russia will be the largest horticultural LED lighting project in history.

    Over 120,000 luminaires will illuminate a greenhouse growing area of 25 hectares, equivalent in size to about 40 soccer pitches. It will significantly increase the supply of domestically-grown tomatoes and cucumbers into the Russian market and aid the Putin government’s aim of increasing self-sufficiency in vegetables.

    The greenhouse complex, located in Lyudinovo, 350 km south west of Moscow, will enable year-round growing, help boost yields – especially in the winter – and will save 50 per cent on energy costs compared to conventional high-pressure sodium lighting.

    The lighting will use special ‘light recipes’ optimised for growing tomatoes and cucumbers to provide the exact light requirement at each stage of the growing cycle.

    Irina Meshkova, deputy CEO and general director of Agro-Invest, the Russian grower behind the scheme, told Lux: ‘We’ve a reputation for innovation on a large scale and these LED grow lights are definitely the future.

    ‘They deliver the right light for the plant, exactly when and where the plant needs it the most, while radiating far less heat than conventional lighting. This allows us to place them much closer to the plants.

    The LED installation will significantly increase the supply of domestically-grown tomatoes and cucumbers into the Russian market and save 50 per cent energy compared to low-pressure sodium

    Reply
  9. Tomi Engdahl says:

    Horticulture LEDs extend color choices
    https://www.edn.com/electronics-products/other/4458958/Horticulture-LEDs-extend-color-choices

    Lumileds has added three new color options to its Luxeon SunPlus 35 line of LEDs, enabling wavelength tuning in both greenhouse and vertical farming applications. SunPlus 35 LEDs are binned and tested based on photosynthetic photon flux and come in 3.5×3.5-mm packages.

    The new deep red (650 nm to 670 nm) and far red (720 nm to 740 nm) wavelengths combine with the existing royal blue (445 nm to 455 nm) to enable spectrum customization for the crop being grown. Other colors include lime (broad spectrum) and three shades of purple with varying contributions of blue (2.5%, 12.5%, and 25%). With light-emitting surface sizes of 15 mm, 19 mm, and 32 mm, the Luxeon SunPlus chip-on-board purple ramps photosynthetic photon flux to increase greenhouse productivity and time to market.

    Reply
  10. Tomi Engdahl says:

    Home Horticultural Osram and partners release horticultural LED development kit
    Osram and partners release horticultural LED development kit
    http://www.ledsmagazine.com/articles/2017/10/osram-and-partners-release-horticultural-led-development-kit.html?eid=293591077&bid=1912567

    Working under the LED Light For You initiative, Osram Opto Semiconductors, LEDiL, Mechatronix, Cezos, and ICT Suedwerk have developed a kit or reference design that allows developers to quickly evaluate and explore LED-based horticultural lighting.

    LED Light For You (LLFY) partners Osram Opto Semiconductors, LEDiL, Mechatronix, Cezos, and ICT Suedwerk (along with engineering partner EuRepTec) have announced an LED-based horticultural lighting developer kit intended to allow product developers to explore the solid-state lighting (SSL) alternative to high-pressure sodium (HPS) lighting in horticultural applications. The kit is a four-channel design that allows developers to mix light from a combination of hyper-red, deep-red, deep-blue, and cool-white LEDs from Osram.

    Reply
  11. Tomi Engdahl says:

    NASA growing food in space: An amazing technological feat
    https://www.edn.com/design/analog/4459016/NASA-growing-food-in-space–An-amazing-technological-feat

    When future astronaut crews begin living and working at more distant destinations in space, they will need to take a little of the Earth with them to help them breathe and allow them to eat their vegetables.

    LED lighting

    NASA tests have determined that LED lights are the optimum single source lights for plant growth on Earth as well as in space.

    you can have monochromatic lighting or easily convert to a mix of lighting composed of different wavelengths with LEDs, and finally, LEDs produce little or no heat so they can be located much closer to the plants than other lighting, especially in small spaces.

    Why the different colors? NASA research findings include the following:

    Red Light (630-660 nm) is essential for the growth of stems, as well as the expansion of leaves. This wavelength also regulates flowering, dormancy periods, and seed germination.
    Blue Light (400-520 nm) needs to be carefully mixed with light in other spectra since overexposure to light in this wavelength may stunt the growth of certain plant species. Light in the blue range also affects the chlorophyll content present in the plant as well as leaf thickness.
    Green Light (500-600 nm) was once thought not to be necessary for plants, but recent studies have discovered this wavelength penetrates through thick top canopies to support the leaves in the lower canopy.
    Far Red Light (720-740 nm) also passes through dense upper canopies to support the growth of leaves located lower on the plants. In addition, exposure to IR light reduces the time a plant needs to flower. Another benefit of far red light is that plants exposed to this wavelength tend to produce larger leaves than those not exposed to light in this spectrum.

    Scientists have found that including white LED light mixes in arrays serve as a way to ensure plants cultivated indoors receive all the photosynthetically active radiation needed to optimize their health, growth, and yield.

    Reply
  12. Tomi Engdahl says:

    Science advances in matching LED lighting to horticultural needs (MAGAZINE)
    http://www.ledsmagazine.com/horticulture/articles/science-advances-in-matching-led-lighting-to-horticultural-needs.html?eid=289644432&bid=1940830

    LED-based SSL products are bringing revolutionary advancement to indoor and greenhouse growing operations, explains MAURY WRIGHT, but there remains much to be learned about the differing light needs of varying plant types and even how needs change during a growth cycle.

    High-power LEDs are bringing similar revolutionary benefits in life-science applications such as horticulture that the solid-state lighting (SSL) sources are offering in the general illumination area -energy efficiency, low/no maintenance, spectral control, and beam control. But plants need different things from light relative to people, and human-oriented metrics such as efficacy (lumens per watt – lm/W) or CRI may or may not provide any indication as to whether an LED luminaire will deliver results for vegetable and flower growers.

    SSL could truly revolutionize the global horticulture industry including edible produce and the similar floriculture or flower-centric industry. LED-based lighting will also play a critical role in cannabis growing, especially as the legal climate evolves for both medical and/or recreational marijuana usage.

    SSL roles in horticulture

    The use case for LEDs in fruit and vegetable farming centers around extending the growing season, especially in cold regions with short summers. Artificial lighting, primarily high-pressure sodium (HPS) lighting in the past, has long been used in greenhouses to extend tomato seasons, for example. We will discuss what LED lighting adds to the story throughout this article, but one clear advantage of SSL is the fact that the lighting produces no heat and growers can use interlighting – placing lights near/between the plants, run either vertically or horizontally to deliver light to the lower foliage that doesn’t receive much direct light from above as the plant grows.

    The greenhouse use case for LEDs is primarily as a supplementary light source to the sun, although the artificial lighting is increasingly vital during the colder and shorter days of winter. Cannabis also requires greenhouse-like space where plants can grow vertically. But most legal cannabis growing operations are for now indoors, and require electrical fixtures as the primary light source.

    Where LEDs are having the greatest impact, however, is in growing leafy greens and herbs that only reach heights measured in inches and that can be grown in layers or racks with each layer having a dedicated set of LED luminaires relatively close to the plants, again enabled by little to no heat radiated by the LEDs. The layering enables so-called urban or vertical farms to occupy relatively small growing spaces inside buildings near population centers, while optimal lighting and technology including hydroponics enables much faster plant/harvest cycles than can be achieved outdoors.

    Reply

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