The demand for electrical energy is integral to life in the 21st century. Its basic use started out in communications and lighting. Increasingly, transport, appliances and multimedia products powered by electricity pervade many aspects of everyday life. This is especially so during rainy seasons where overcast skies and the preference for indoor activities drives up the demand for electrical energy. Rainfall is often an overlooked source of renewable energy due to its unpredictable nature. The problem is to conceive an integrated framework involving the efficient capture and utilisation of rainfall as a renewable energy source in a tropical urban environment. The proposed solution is to capture rainfall via a distributed network of energy-harvesting devices, and the harvested energy would be utilised for energy demands. The basis of this proposal is the energy-harvesting device, REGN, which can be quickly and reliably deployed in a populated tropical environment. Ideally, the device would be located in the region 20 degrees latitude North and South due to the presence of a prevailing monsoon season and high annual rainfall. The exposed exterior of the device is specifically made from materials that are able to provide ample shield from tropical heat and UV radiation. Surfaces in contact with acidified fluid and moisture (due to contamination from airborne or surface pollutants) would be specified with materials inherently able or treated to resist corrosion. REGN takes on the guise of a spigot-type insert that could easily replace any gutter pipeline connection joints. The insert generates electricity by utilising the motion of rainwater diverted from roofing structures along gutter pipelines. This is achieved via electromagnetic induction, as magnets located on a spindle within a funnel column are spun on a plane, while copper coils simultaneously lead to an external output connector. As fluid flow is designed around a planar cross-section, the design can be easily adapted to American (rectangular) and Commonwealth (circular) pipeline standards. Multiple instances of REGN could be linked to form a larger network of energy harvesting devices. This is especially useful in the case of a high-rise structure, where these modules can be staggered along vertical gutter pipelines to make use of the height advantage to achieve higher velocity flow rates. The compounded yield of REGN would thus be significant when adopted in a city center yet not encroach further into the amount of sunlight filtered to the ground level of a concrete jungle. Such networks could then be scaled against the actual number of occupants and deployed in appropriate amounts. This solution is unique because it leverages the overlap of demands in regions of concentrated human activity and the occurrence of an often-overlooked natural phenomenon to augment these demands. REGN allows for the realisation of the “on-demand” potential of rainfall fulfilling human needs as a subtle, symbiotic implementation within a compact assembly. The device’s compact frame allows for practical use of magnetic levitation. A form of “magnetic bearing” is derived from a tight-knit spacing of weak-component magnetic fields acting at a distance. This brings about the much-needed advantage of reducing friction generated by the rotation of the spindle core to a point, in order to maximise efficiency. The levitated spindle core also has an excellent clogging-resistant characteristic, due to its dynamic motion as a component group that is not physically attached to the funnel housing that is situated within. Modules are ideally installed among gutter pipelines in dense urban settings. This is a strategic advantage as the device would be instantly co-located where there is human presence. This ensures that delivery of electrical energy generated could be quickly routed to a point of human consumption within close proximity. Unlike conventional methods of harnessing renewable sources of energy, REGN networks do not require the additional construction of costly infrastructure or large-scale modifications to existing elements in the built environment. REGN is comparatively low-tech and simple. The external housing of the device can be quickly disassembled, as fastening is achieved with reusable cable ties. Magnets are held in place by repulsive forces acting on each other while the housing design follows the contour of the funnel column, allowing for a snug, foolproof fitting. The spindle core was designed to be assembled in a foolproof procedure with components that can be put together in only a single configuration. REGN is therefore easily serviced due to the ease of disassembly and clear impellers with a narrow spindle profile that allows for quick visual checks along the funnel column. Components anticipated to receive the most amount of wear are readily available (for example, worn spindle core tips could be replaced with that of discarded ballpoint pens).

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