Howard Winter wrote: >> I'm not sure about the storage system mentioned here but wouldn't you >> need to raise 36,000 kg 10 meters to get 1 kwh? Is there some trick to >> the hydraulic system that would let it work with less mass? > > Sorry, my physics is so rusty that I can't remember the conversion > factors in this, Unless you want to use weird units, there are no conversion factors (unless you consider the gravity acceleration a conversion factor): E = f x d = 36'000 kg x g x 10 m = 3.53 MJ = 3.53 MWs = 3530 kWs ~= 1 kWh > The main accumulators for Tower Bridge had weights of about 100 tonnes, I > believe, but I think their full travel was in the range of 6 to 8 > metres, and they hed enough energy to perform at least one full > open-close cycle. E = 100'000 kg x g x 8 m ~= 8 MJ ~= 2.2 kWh Gerhard -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist