Re: [SiliconBeach] Top 10 Tech idea's from Friday nights Drinks .. (not necessarily serious business idea's)

[Clifford Heath]

David, Perhaps a small example would outline my concern. Supposing we had magical materials which weigh nothing, so we can disregard the mass of the train and just consider the payload. Beginning with a single person then, say 100Kg, travelling at 100km/hr. Railways routinely climb slopes up to 1 in 11. Normally less, but 1 in 11 is a common maximum sustained climb. The power required for this hypothetical train to lift this person at this rate is 2.5KW, since they're rising 2.5m/s, with a weight of 970N. Now if this train has a solar cell with high efficiency, say generously 18%, and it is in full noonday sun with the cells on the optimum angle, they make about 180W/m^2. That requires 14 square metres of solar cell, per person. With a weightless train, zero friction or drag, at noonday, with the cells angled correctly. Start factoring in the overheads, and you quickly reach a required 200m^2 per person. Carry 500 passengers, and a 5 metre-wide train would need to be 20km long, or one passenger every 40m of train length. This just *not* a feasible size for a train. Sure, this is a peak load while climbing a hill, and you'd be able to serve that load from batteries for some duration, but those 500 people and a train of comparable weight are still going to need 2.5MW to climb that hill. I could go on... there are a hundred other potential failures in this proposal, but... do you see why I'm skeptical? Clifford Heath. On 30/01/2011, at 3:55 PM, David Lyon wrote: Hi Clifford, I can give a preview yes, but not the whole mathematical equation. General maths are ok.there are a few sensitive IP design solutions that I'm not going into. Firstly, my van in my garage has 7 seats, a 2 litre 90hp petrol motor. Its good for 100kmh on the road. It weighs about 1700kg. Total weight for that with all people is therefore about 2400kg. In the old days, trains many trains were actually made from wood and had wooden wheels. That kept the weight down. For 20 people we are aiming with aluminium and aluminium honeycomb to get something for 900kg. Think what an aluminium 'tinny' boat weighs - four people can go in one of those and I've seen many that weigh as little as 100kg. Think what a cessna or light plane weighs and how they are constructed. To carry 20 people, you need about 150kw to get up to speed. You're going to need enough solar cells to generate that amount of power in a period of six hours to go 300km and batteries to hold the charge. Once the train is moving, it needs less power to keep going. When it is running downhill it is recharging the batteries (regenerative). Also, forget steel wheels. Think of something like mag-alloy or carbon fibre. "Conventional" trains, on the other hand, are 8000kg per carriage and have four 150kw motors. Thats just too heavy to go and attach solar cells to and expect it to work. There's a whole lot of advances in battery technology like Lithium Ion Polymer and advances in solar cells that mean the surrounding technology is much moved on from where it was 5 years ago. It's possible to get people moving along a track with solar cells.. On Sun, Jan 30, 2011 at 11:37 AM, Clifford Heath <clifford.he...@gmail.com> wrote: On 30/01/2011, at 10:43 AM, David Lyon wrote: I'm having trouble even getting a VC meeting with my Solar Train. I'm being told "Since no such technology exists in the market.. (we have no time to even listen to a pitch)" Train speeds in Australia are still 80kmh on average which is the same average speed as what you used to get in the late 19th century. If I can get an order for a full train, each train will be $2.5M so whilst there is some risk there is also some potential to do things on the big scale working from a small base. David, I'm not sure the numbers add up. Can you go through some of the arithmetic concerning the actual energy consumption and requirements of such a train? A lot of the ideas you've touted here seem to me to be a bit suspect in this department. A confident and competent mathematical presentation of the energy budgets would go a long way to convince me (and perhaps, VCs) that you know what you're talking about. Clifford Heath. -- You received this message because you are subscribed to the Silicon Beach Australia mailing list. Guidelines on discussion: http://groups.google.com/group/silicon-beach-australia/msg/351e183e1303508d?hl=en%3Fhl%3Den No lurkers! It is expected that you introduce yourself. 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