Comments by "Tony L" (@tlangdon12) on "Engineering with Rosie" channel.

The rotor configuration is important to the self-starting characteristics of the rotor. The graceful curved blades on some Darrius-type VAWTs are not there to look nice, they actually improve the ability of the rotor to self-start because there is always some part of the rotor that is at the optimal angle of lift to start the rotor turning, and as that part of the rotor turns away from that angle, another part of the rotor is turning into that optimum angle. Self-starting behaviour is a particular difficulty with VAWTs, but it can be overcome with careful design.
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@EngineeringwithRosie I think the question you posed as to whether VAWTs are not efficient enough yet for commercial use is due to a lack of development or an inherent inefficiency is a great question. It's not that they produce no energy; while it is certainly true that there is published data that shows certain VAWT installations did not performed well, these tend to be in poor wind sites where a HAWT would do no better. There is other data from large VAWTs in good wind sites that have produced a lot of energy quite reliably.
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@normnicklette5694 The focus in urban areas needs to be on solar PV for electrical needs and capturing heat for heating needs. Solar PV panels sit unobtrusively on top of most structures and using other large surface areas such roads to gather heat during the summer and stoing it underground where the natural insulating properties of the earth mean that it can be store until it is need in the winter then accessed using heat pumps is the best way to source the heat needed to heat our homes.
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They don't rely on metalic elements that are only found in abundance from China. Australia has 20% of the world's Zinc reserves and can extract Bromine from the sea. They also have better tolerance to high temperatures, making them more suited to hot countries.
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While a mechanical system would be relatively simple, Rosie has neglected to mention the difficulties that VAWTs can have in starting, and also the need for them to cope with high windspeeds, e.g. by feathering the blades. These problems mean that the optimum blade angle is dependent on the windspeed, and a mechanical system would be made much more complex if it had to also factor in the windspeed to its mechanics.
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I'm not sure if you are aware of Vertogen, but they are working on an self-governing variable pitch VAWT mechanism that might improve the efficiency of VAWTs significantly. It might be fair to say that "automatic variable pitch" is the holy grail of VAWT technology as it promises improved efficiency, improved self-starting and another layer of safety against overspeed. Only time will tell if the benefits outweigh the downsides produced by the complexity.
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LiFePo4 batteries are very energy dense. These flow batteries are never going to get small enough or light enough to be used for mobile or portable systems, but for applications where space is not at a premium, they can offer a useful cost savings as they don't rely on any rare elements. Static applications is where they will excel.
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Being ominidirectional also means that they don't need slip rings to transfer the generated power from the nacelle to the round. Slip rings wear out eventually and need maintenance, but then so do the bearings of a VAWT!
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@EngineeringwithRosie I think Drema Boy is suggesting that the generating coils/magnets for a VAWT could be more efficient if they are positioned at the periphery of the rotor rather than in a relatively small PMG driven by a shaft. His point being that the linear velocity at the periphery is greater than at the centre. I don't know enough about generator design to know whether he is right. :-(
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The need for a tower, its foundations, dump loads, braking system, and the on-going maintenance all make small-scale wind more expensive than the simpler PV or PV + battery option. For most urban situations, a PV + Battery system combined with variable tarrifs is going to the most cost-effective solution.
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These flow batteries should be ideal in your application, but Redflow are not focused on the residential market yet. Their focus is on grid-scale applications, and it is there where the money exists to improve the product to the point where residential customers will be able to buy them and be happy with the. The moving parts should be source of concern - in a grid-scale implementation there is enough redundancy for the failure of a single battery to be of no conseqence, but if the pump fails in a residential application, you are stuck; neither being able to charge nor draw on the power stored in your battery. Perhaps Redflow will develop a high-avalability version of their product with a redundant or hot-swap pump, or perhaps a solid-state pump will become available.
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There might be more environmental concerns with boring holes. Even with a geological survey, you can't be sure what you will hit on the way down, and what you might do to the ground water in the area.
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I think you have misunderstand that the BIG advantage of the technology is that you have to reach 700C because you get a much great heat storage capcity at this temperature, not just because 700C is really hot, but also because it causes the aluminium to melt.
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No! When you look at the engineering and research going into Wind Energy Conversion Systems its apparent that Windmills are are the forefront of our technical development. So much advanced knowledge in Materials Science has been gained as a result of wind turnbine development, and AI will play a part in maximising the performance of wind turbines for years to come.
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Vertogen are working on just such a design.
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Home heating might only be required for a fraction of the year in Aus. but in the UK and northern Europe we have millions of homes that need heating for nearly half a year, and personally I'm spending about 5000 AUD a year to do so at the new energy prices, so anything that might cut is of interest.
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Winglets on the wingtips would allow VAWT blades to create its own ducted shroud as it rotates.
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Yes, its entirely possible. Vertogen are working on just such a design.
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They were hit quite badly by the pandemic.
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@EngineeringwithRosie Are you familiar with Qblade? I've done some work with the VAWT modelling in Qblade as part of my research into VAWTs.
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There are some Foam Glasses available that have very significant compressive strengths and very high thermal insulation values if heat loss through foundations is a concern. (Look up FoamGlas Perinsul HF)
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There is a company in the UK called Vertogen that has a patent on a mechanical pitch control mechanism.
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Given the Infinity Train's route, even if it couldn't generate 100% of the power needed to return itself to its starting point, solar panels on the roof of the motor units and battery cars could generate the additional power needed, and they would continue to do so on the return journey (if it was done during the day). The Infinity Train and eDumper are examples where using the very lightest battery is justified.
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I would share your concerns. A better arrangement to regulate power in high winds is to set the blade angle for as much anti-rotational torque as you can without stalling the blades (and then zero torque), but if you have no ability to change the pitch you are left with the electrical torque that the generator can produce, and as you observe, if this fails, you will get a runaway. To my mind any turbine needs an emergency brake, so it would be better to plan on implementing them from the outset.
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Anything that can increase the wind speed seen by the turbine in low wind conditions will help, but in high wind, it would be ideal if the funnels could be reversed so that their action helped protect the turbine.
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To get you started, there are a range of options as to how you might vary the pitch of the turbine blades; using a cam, you might turn the blade through less than 180 degrees, or using a gear mounted on the blade spar, you might turn it through the full 360 degrees. The cam or gear might be operated by a mechanical arragement or by a motor operating under the control of a fast acting electronic controller. The interesting bit is the calculation of the apparent wind, lift, drag, resultant lift and torque vectors and then controlling and optimising these to extract the most energy from the wind. Having full control over the blade pitch allows starting to be optimised, and for the turbine to be braked in high winds.
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@kentonian Efficiency isn't the name of the game here. What is needed is clean energy, and storing renewables is cleaner than buring gas, providing care is taken during the production process.
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@EngineeringwithRosie Lower to the ground will definitely help, but the rotor diameter tends to be lower, so the force at the tips is lower. VAWT tip speeds never reach the supersonic!
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Part of the issue here is that the only leverage other countries have on the countries that are not making an effort to reduce flaring is not to buy the product, and if you don't buy the product, you can't have a say in how it is produced.
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@Froggability While it's true that the marine industry has solved all the issues, but the solutions are all very expensive compared to those that can be deployed inland.
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Very interest comments. Can you explain any more about how the energy in the tip vortices was harvested as thrust for the turbine?
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@GarretKrampe Thank you.
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They are almost certainly too heavy (weight vs. energy density) for mobile applications.
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Vertogen have been working on this for a number of years.
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@ДэнКошман HAWTs and VAWTs place a great deal of cyclical stress on the components of the machines, so both are subject to failure due to fatigue. I don't think you can say that only people who don't know much about aerodynamics are engaged in VAWT research; I tend to agree than many people tend to ignore the fundamental aerodynamic issue with VAWTs - that the blades experience a variable local airflow as they rotate, but there are aerodynamicists working on variable pitch VAWTs specifically to reduce the effect of this variable airflow. Whether the complexity of the variable pitch mechanism provides a useful degree of additional energy extraction is still to be seen, but these are aerodynamic experts who are working with VAWTs.
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That could work, e.g. installing them in a chimney, but you have to be careful you don't impede the primary function of the chimney which is to allow the poisonous combustion products to be dumped into the fresh air.
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Sand doesn't go through a phase change so it can't absorb as much heat. This means that the specific heat capacity (the measure of how much heat a material can store) of the blocks is about twice as high as sand.
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Vertogen are working on just such a system.
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You instantly loose the benefit that the turbine is omnidirectional when it is vertical. It's not when it is turned on its side.
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The technology has potential to be very cost effective, so it's good that there are some grid-scale implementations where there will be enough investment put into it to really see if it can live up to its promise. I think it's a bit early to say that it is DoA.
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@eugeneputin1858 Most if the weight of the Redflow battery is water, which can be added by the local distributor once the battery is on site.
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@rklauco It does make a lot of sense for distributed heat storage in cities.
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It will be while before it scales more cheaply than a Telsa battery.
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Vertogen are working on just such a system.
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Really interesting video and comments. I think this technology could have an application in relatively small scale residential set-ups. The ability to change the rate of heat extraction using simple modulation of the pump that is pumping the inert gas around the heat store is very useful as it allows for the production of low levels of heat for heating efficient buildings, that might only need flow temperatures of 27C even on the coldest winter days, and producting lots of hot water on demand at 50C+, something that Heat Pumps struggle with. In communal installations, it could be used just for hot water production, with space heating being done via heat pumps.Clearly large scale installations can be more efficient due to the greater relative surface area of a small cube of material.
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The prices will fall as they scale up their production, and figure out how to supply the residential market without incurring significant additional costs.
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@worskaas I'm not aware of the needing maintenance checks on a regular basis. They just need repairing when they go wrong.
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