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A vision of factory farming in the 21st century Vertical Farms By LEO SIMPSON Planet Earth now has seven billion hungry humans to feed. How will we feed the increasing hordes in years to come? Arable land is decreasing and higher yields are harder to obtain. This Australian technology may provide part of the solution, combining bioponics, LED illumination and computer control to deliver quality food in rapid time. 16  Silicon Chip siliconchip.com.au H ow many readers think that you need ultraviolet light to sustain photosynthesis in plants? After all, whether they use sunlight or artificial illumination, greenhouses inevitably expose their crops to ultraviolet radiation. Well, it turns out that UV is not necessary. To sustain photosynthesis and growth, plants only need red and blue light. They don’t need green light either; they reflect it, which is why plant leaves are green! A superb crop of basil after just a few weeks And they certainly don’t need growth in the Vertical Farm. Not a single bug ultraviolet; too much UV causes (or any leaf damage!) to be seen . . . sun-burn to plants, just as it does with humans. In fact, plant biologists refer to phoSo it transpires that the artificial light tosynthetically active radiation (PAR) needed for plants grown in greenhouses as light ranging in wavelengths from can be simply provided by high inten- 400-700 nanometres, precisely what can sity red and blue LEDs. But why would be sourced from LEDs and since plants you want artificial light anyway? Why largely reflect green wavelengths, we are not simply use the Sun? only interested in red and blue LEDs. Well Ol’ Sol is fine for traditional land Photosynthetically active radiation farming but we’re talking about much (PAR) is usually measured in micromole more intense cropping – the factory photons per square meter per second farming of the future. (μmol photons/m2/sec); one micromole Actually, there has been a lot of re- being one-millionth of a Mole. search into the use of artificial light for A mole of photons is the same as photosynthesis. Avogadro’s number: 6.02 x 1023. And it just happens that photosynthesis is directly proportional to the number of photons falling on the plants: about nine photosynthetically active mole photons is required to produce one mole of oxygen, the product of photosynthesis. Incidentally, there is also quite a lot of current research into artificial photosynthesis, ie, where no plants are involved, just microorganisms. For the purpose of this article though, we are interested in artificial illumination for use in green-houses. We should also define the term “bioponics”. This is different from hydroponics in that the nutrient mix contains biologically active microorganisms. The micro-organisms are crucial in enabling the plants to take up all the vital nutrients. Without the micro-organisms, hydroponics can be very much a hit-and-miss process. Greenhouses waste a lot of space While greenhouses and hydroponics can greatly increase crop yields, greenhouses themselves are not very space efficient. For a conventional Here’s a complete Vertical Farm, taken with a crop growing and the LEDs illuminated. The containers in front hold the nutrient solutions (with their pumps); the cabinet alongside contains the computers and electronics to drive it. siliconchip.com.au March 2012  17 Another, view of the Vertical Farms’ XT432, which can hold up to 23,760 plants growing much faster than they would using normal farming methods. greenhouse, up to 60% of the available space is needed for aisles so that humans can get access to all the plants. Enter . . . Vertical Farms Here is where the Vertical Farms concept comes into play: instead of growing plants on one level, it can be done on many levels. As the photos show, this is no longer a greenhouse; it is a large module with plants growing on 12 levels, spaced with about 400mm between them. With the plants growing on so The start of the process: the white plastic trays are filled with reusable growing medium (not soil!). Most of the photos in this feature were taken “in situ” with the Vertical Farm operating, hence the magenta-like tones. 18  Silicon Chip many levels, artificial illumination is mandatory and this is where the high intensity red and blue LEDs enter the equation. Each plant tray is exposed to high levels of red and blue light for between 12 and 17 hours a day and subjected While no medium has yet been placed, this shot shows how it is levelled off with the large blue wheel brush, ready for planting. The seeds are dropped onto the dry medium, watered and the trays then placed in the Vertical Farm. siliconchip.com.au Various stages of the growth cycle: after the spinach seeds are sown into the growing medium, the trays placed in the 12-level Vertical Farm so that their roots can soak up nutrients periodically flooded through the system through the watering system (patent-pending). They are irradiated by red and blue high intensity LEDs for up to 17 hours per day to finally produce the crop at right. No pesticides are needed because there are no pests! to a carefully designed growth cycle with all the liquid nutrients supplied at optimum levels, under computer control. This very long “growing day” and optimum levels of nutrients means that the time from initial seed planting to harvest is very short; just 21 days. And not only is the turnaround very short but the crop yields are much higher than can be obtained by any other means. The plants are in a temperaturecontrolled environment and have no exposure to pests. No pesticides or herbicides are required. This is true “organic” agriculture (although we hate the term “organic”). In fact, since the plants are not handled at any time, so they do not even require washing. And if the distance from grower to customer is short, no refrigeration is required either. So that’s the concept: factory farming in the truest sense, not subject the vagaries of weather or climate, soil fertility, pests, competition from weeds and so on, with optimum application of nutrients at the exact time the plants need it. We hasten to add that this is not just a concept nor some elaborate scheme for future development. It is being used right now to produce fresh produce, as we saw when we visited the Vertical Farms factory, at Coolum Beach in Queensland. So let’s fill in the details of this multi-level growing system. XT432 Farm Block This large module is 9 metres long, 2.1 metres wide and 3.9 metres high. It is fabricated mainly from stainless steel, with plastics used for all the piping, plant trays, lighting units and so on. And here’s what they look like after just a few days of LED illumination from above and nutrient feeding from below. You can clearly see the banks of red and blue high-intensity LEDs above – they’re so bright eye protection must be worn. siliconchip.com.au The module has a central aisle (shown on first page of this article) which gives access to the piping and wiring on all the levels, and after allowing for this aisle, the total growing area is 194 square metres, ie, about ten times the floor area occupied by the module itself. Vertical Farms envisage that a typical factory farming installation would have maybe dozens of these modules, all networked to a central control system. After allowing for access aisles for an elevating work platform (similar to those used by electricians when changing lights in buildings with high ceilings), a 2000 square metre warehouse could accommodate up to 55 of these modules, giving a growing space of 10670 square metres or just over one hectare. In other words, that is about five times the area of the warehouse. Speaking of nutrients from below, here’s a view of the same trays at left lifted clear of the carefully-controlled nutrient medium. You can see how the roots emerge from the bottom of the trays in search of the liquid underneath. March 2012  19 Some idea of the scope and magitude of the XT432 Vertical Farm can be gleaned from these two photographs. The photo above is included to give some relativity of size, which is obvious when compared to the three people standing in front. Normally at this close range eye protection is mandatory to prevent eye damage. At left just part of the growing racks and LEDs can be seen – each of the 12 (high) racks contains 36 growing trays and each tray contains 55 pockets containing individual plants. In this photo only a few racks are visible and even then, not all trays can be seen. This photo was taken before any medium or seeds were planted in that growing area. By contrast, a conventional green- could be over three hundred tonnes. ing trays, giving a total of 432. Each house with the same floor area would That’s a lot of healthy green vegies! growing tray is illuminated by 32 high There is no such thing as “seasonal” intensity red and blue LEDs, consumhave a growing space of about 1000 square metres or less. So using XT432 crops – you simply “dial up” the ing about 51W in total. modules would give ten times the season needed to suit the crop and/or The LEDs themselves were chosen growing space of a conventional market demand. after exhaustive tests to determine the Typically, if an operator wanted to best power to light ratio. greenhouse. As already noted, there are 12 levels grow a variety of different crops simulin the XT432 module and these are taneously, a number of XT432 module High light levels split into three bays, each of which would be employed. It has to be said that the light inEach of the 12 levels has 36 growis separately controlled and tensity is extremely high and can therefore have different very uncomfortable. Anyone growing cycles. who is near the machine Normally the same or a during its “daylight” hours similar crop is grown in for more than a short length each bay since all bays use of time must wear protective the same nutrient mix and glasses to avoid the risk of lighting levels. Macular degeneration. With the same crop in each Each growing tray has 55 bay, you can have the growpockets which hold the growing cycles each staggered by ing medium; you can’t call it a week so that harvesting can soil. It is actually a red clay be done progressively, week gravel into which the seeds by week. are sown by machine. Such an installation with The pockets are quite deep 55 XT432 modules could and they all sit in a lower tray produce around 6.3 tonnes of which holds the water with leafy green vegetables, such all the nutrients. The nutrias loose-leaf lettuce, spinach ent mix is very complex and or rocket, per week. Over the TLC for plants! With the significant amount of heat being is not just a simple fertiliser generated, the high efficiency air conditioning system for course of a year, the output the plants is also rather significant. solution. 20  Silicon Chip siliconchip.com.au BRIGHT IDEAS. STOCKED HERE. Let element14 bring your ideas to life with an array of 10,000 lighting products and solutions, including design resources like application guides, white papers, notes and more. And with local service and technical help, you can count on us to support your needs – 24/7. As a part of the Premier Farnell group, element14 brings you 70+ years of trusted electronics distribution expertise, along with an innovative online engineering community, where you can collaborate with experts, access technical information and use helpful tools. So trust element14 to power all your bright ideas. Global portfolio of industry leading manufacturers: HOW MAY WE HELP YOU TODAY? WEBSITE: FAX: SALES: MOBILE SITE: m.element14.com TECHNICAL SUPPORT: FLEXIBLE PAYMENT OPTIONS: au.element14.com/lightingsolutions nz.element14.com/lightingsolutions PHONE: Australia 1300 519 788 New Zealand 0800 90 80 80 siliconchip.com.au Australia 1300 361 225 New Zealand 0800 90 80 81 au-technical<at>element14.com nz-technical<at>element14.com au-sales<at>element14.com nz-sales<at>element14.com March 2012  21 The new global face of Farnell Instead there is a wide range of trace elements, including iodine and selenium, as well as a mix of microorganisms. In other words, the mix is biologically active, not sterile, as in normal hydroponics. The nutrient mix is a proprietary product of Vertical Farms and an important factor in the overall success of the concept. XT432 control system The system is controlled by a main processor PCB with isolated I/O, analog inputs and PWM outputs. The display interface is a Comfile Technologies colour touch panel. This allows the operator to select a crop species, start, stop and pause a growing cycle, check alarms and monitor water quality. It also allows a simple pH and EC (electrical conductivity) probe calibration with a couple of touches on the screen. Signals to and from the main control PCB are fed via a “buffer” PCB, which carries control relays that can be switched to automatic/off/manual, via on-board switches. The board also takes care of fault 22  Silicon Chip detection and time delays etc to allow pump operation in the event of controller failure. Manual/auto switches are also provided on the front of the control cabinet. The switches on the relay board are provided as a last resort. The main control PCB feeds PWM signals to a purpose-designed driver PCB which in turn controls the levels and colour ratios of the lighting. Each row of LED panels can be individually isolated. The LEDs are fitted to strip PCBs which in turn plug into a main PCB, carrying PWM-controlled LED drivers for each colour. Water quality and nutrient levels are controlled via a specially designed, isolated amplifier PCB that piggybacks the processor PCB. This allows dosing pumps to be run as required. Two large pumps deliver nutrientladen water to the growing trays according to a schedule dictated by the time of day, crop type and maturity. The pumps are 2.2kW single phase units, controlled by a FutureWave dual pump control (see the FutureWave review in the June 2011 issue of SILICON CHIP). The pumps only run for a few While the touchscreen control panel can allow manual overrides, the system is very much automated and the screen is largely for information. Sensors built into the system will sound alarms on the manager’s mobile phone. siliconchip.com.au The trays are then fed through a machine which looks like a mini car wash with large brushes and water sprays. They are thoroughly washed and sterilised using a hydrogen peroxide solution. Then the whole planting/growing cycle is repeated. minutes every few hours and pump a load of nutrient through some special valves (patent pending) so they fill all the trays in a bay at once. The water then runs out of the trays into a big pool under the machine, which is constantly stirred by a circulation pump and its pH and EC are monitored and adjusted after each tray flood cycle. Alarms are available for low and high water, loss of priming for various pumps and power failure. Alarms are routed to the display interface screen from the relay board via a Cubloc module and also to an SMS modem, which sends warning messages to the manager’s mobile phone. It also sends a message when a crop growth cycle is finished and needs attention. With all those LEDs and pumps, the maximum power is about 9.5kW/ phase (ie, 28.5kW total) but normally runs well under that, with the computer-controlled light periods. Power consumption is typically 100kWh per day. Each XT432 factory unit requires a 415V 40A 3-phase connection. And with all that power being dissipated, a big air-conditioning system is mandatory to control the overall temperature. Planting and harvesting Since the XT432 modules are essentially fully automated, the only time that humans are required on site is for planting the modules and harvesting. Both these processes employ specialised machinery as well. For planting, the growing trays are run through a machine which fills each pocket up with the growing medium siliconchip.com.au Helping to put you in Control Control Equipment USBDroid This arduino board combines the functionality of the Freetronics Eleven along with a USB hostmode controller and a microSD memory card. Connects to Android devices. FRA-011 $63.59+GST (red clay gravel) which is then levelled off with a large rotary brush. The seeds are then sown into all the pockets in the growing trays which can then be loaded into the bays in the XT432 modules. At harvest time, the growing trays are removed from the XT432 and fed into a machine which lops off all the crop. The output is then packed immediately for distribution to supermarkets or restaurants. The growing medium is then emptied from the trays and the gravel and root mass is separated into a hopper. It can then be composted or used as soil top-dressing. The trays are then fed through a machine which looks like a mini car wash with large brushes and water sprays. They are thoroughly washed and sterilised using a hydrogen peroxide solution, then the whole planting/ growing cycle can then be repeated. All told, the Vertical Farm system is much more automated than typical greenhouse operations. And while it may seem power hungry, it is no more so (perhaps a good deal less) than a greenhouse operation growing an equivalent amount of produce. Will it become the factory farming system of the future? Only time will tell, but Vertical Farms are doing it right now and can show the world how. Acknowledgement: Our thanks to John Leslie of Vertical Farms Systems Pty Ltd (www. verticalfarms.com.au) and to Gary Smith, of GD Integration, (dms<at> SC southcom.com.au) Industrial ON-OFF Switch 22mm dia. Fitted with 1NO contact block. Can fit additional NO or NC contact block HER-235 $9.95+GST DIN Rail Cutter. This easy to use Din Rail Cutter is ideal for cutting 35x7.5mm steel din rail (Top Hat style). HET-070 $99.95+GST J,K Thermocouples Thermocouple sensors mounted in a 50 mm long, 5 mm diameter stainless steel probe. 2 wire Glass lead is 1 m long. Range - 0 to 400 ºC CMS-010 & CMS-015 $49.95+GST High Temp. 24VDC 100W Power Supply Designed to operate over –20 to 70 degC with 3 year warranty. 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