Polydome Concept Overview V.3 This feedback will provide essential information for how to most effectively distribute annual crops so that they continue to produce effectively. In terms of light demand, the layout of the greenhouse has been carefully conceived to ensure that shading does not interfere with the growth of most crops. The tallest crops are placed on the north side of the greenhouse, and they are interplanted primarily with shade-tolerant varieties. Moreover, these fruit trees do not fully shade the ground below them. In some areas, however, it may be desirable to add supplemental light sources, particularly as technologies improve and high-powered LEDs become available and afFordable. • Advanced Logistics Some of the logistics features that we have included in our model of the Polydome greenhouse include: • A central processing bay where all harvested crops are delivered either automatically or semi-automatically. This space allows several workers to sit together in a social environment while processing crops rather than working individually in distant parts of the greenhouse. A series of Nutrient Film Technique (NFT) hydroponic channels organized in a fanshaped pattern over the annual crop zone, causing minimal shading. This section of the NFT system also feeds into a more concen- trated section of hydroponic channels (with a mushroom production zone located below them). All of the channels are installed such that plants float through them arriving at the central processing bay just as they reach harvestable age. RFID tags associated with each plant track when it was transplanted into the hydroponic zone, controlling its timed arrival in the processing bay. • Movable, narrow platforms that travel on rails and can be strategically lowered allow for the harvesting of some of the taller and larger crops. This increases the ease of harvesting, reduces the need for ground access, and prevents unnecessary soil compaction. A system of steel cables attached to the central processing bay allows for easy and low-tech delivery of harvested products. Containers hung from these steel cables can be filled with harvested crops and sent directly for processing, using a combination of gravity and electric pulleys. ground-level access. They must do this without shading crops below, and, ideally, using a minimum of electric power. Flowing water or gravitybased systems are a good option to investigate. The Possibility for Additional Modules Because the Polydome system is modular, composed of a number of interacting pieces that can be exchanged like lego blocks, it is possible to replace modules that are not functioning well or to develop entirely different modules. A particularly promising module that was explored during the research phase was the possibility of a tropical zone. For market reasons, it was an especially attractive option, since many tropical crops are high value and in demand. Moreover, their production in distant locations automatically makes them more expensive due to import tariffs and transport costs. Local production could potentially be quite cost competitive. However, due to lack of sufficiently detailed data on growing tropical crops in greenhouses, we did not include it in the current model. A tropical module could be particularly interesting if a greenhouse can be located near a free source of heat (such as a data center or a number of industrial facilities). These are just examples of some of the logistical arrangements that could be used within a Polydome greenhouse. Working out all of the technical possibilities is a separate task from this concept development. Regardless of how they ultimately function, these logistical features must facilitate harvesting, simplify transport of crops from across the greenhouse to the logistics center, and reduce need for • Polydome: High Performance Polyculture Systems 35 Pagina 34
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