H F Posted September 10, 2019 Author Posted September 10, 2019 What is the head please? Not sure I follow that.
Jeremy Harris Posted September 10, 2019 Posted September 10, 2019 3 hours ago, Home Farm said: What is the head please? Not sure I follow that. The vertical distance in metres from the turbine outlet to the surface of the water in the top reservoir that's feeding it.
SteamyTea Posted September 10, 2019 Posted September 10, 2019 1 minute ago, Home Farm said: What is the head please? Not sure I follow that Get the book quick.
H F Posted September 10, 2019 Author Posted September 10, 2019 1 hour ago, SteamyTea said: Get the book quick. LOL - is it explained in the book?
H F Posted September 10, 2019 Author Posted September 10, 2019 3 hours ago, JSHarris said: The vertical distance in metres from the turbine outlet to the surface of the water in the top reservoir that's feeding it. Thanks Jeremy.
Jeremy Harris Posted September 10, 2019 Posted September 10, 2019 As a first step, it might be an idea to try and make a vee notch flow weir and calculate how much flow you have. Knowing that, and the head, you can calculate the potential power, and halving that is probably pretty close to what you might get from a small hydro system. There is an online calculator for measuring flow with a vee notch weir here: http://www.meracalculator.com/physics/fluid-mechanics/v-notch-weir-discharge.php
ProDave Posted September 10, 2019 Posted September 10, 2019 5 hours ago, Home Farm said: Will look into undershot wheels this afternoon. You might have enough drop in one place to go with an overshot wheel, undershot will not get much power out. This describes the different types: https://en.wikipedia.org/wiki/Water_wheel#Summary_of_types Go with the best the height you have available allows. I only have a tiny drop so undershot is my only option, but you could probably manage Probably a Breastshot wheel with the wheel about twice the diameter of the drop you have available.
A_L Posted September 10, 2019 Posted September 10, 2019 2 hours ago, Home Farm said: What is the head please? Not sure I follow that. Some turbines have a suction tube below the 'spinning bit' and strictly speaking the head is from the top of the reservoir down to the unconstrained water escaping from the turbine. With a small head you are probably looking at some sort of cross-flow turbine or just possibly a Poncelot 'wheel' (I kid you not ?) Examples of both here http://www.waterwheelfactory.com/history.htm
scottishjohn Posted November 5, 2019 Posted November 5, 2019 been contemplating hydro -AGAIN somewhat different situation 2lpersec (7200litres pr hour)and 110m head can make 5kwph -thats basically a 4" going to a 2" input turbine at bottom of quarry now the stream/land drain I have -does not flow enough all year round -- so was thinking, as I do 2000ltr tank at top of hill fed by stream - with a syphon pipe --like a toilet cistern - so when level in tank gets up to full it starts the flow and keeps on till its near empty --It fills up again and repeats what have i missed? the vacum created by that drop will certainly pull the water out of tank will be testing actual output soon and throughout next year
SteamyTea Posted November 5, 2019 Posted November 5, 2019 (edited) Power = Mass x Gravity x Height x Efficiency Power = 0.002 [m3.s-1] x 9.81 [m.s-2] 110 [m]x 0.9 [eff] Power = 1.94 kW About the same as a Honda generator that costs 600 quid. (I may have misunderstood the flow rate) Edited November 5, 2019 by SteamyTea
scottishjohn Posted November 5, 2019 Posted November 5, 2019 (edited) 16 minutes ago, SteamyTea said: Power = Mass x Gravity x Height x Efficiency Power = 0.002 [m3.s-1] x 9.81 [m.s-2] 110 [m]x 0.9 [eff] Power = 1.94 kW About the same as a Honda generator that costs 600 quid. (I may have misunderstood the flow rate) sowmehere i gone wrong with my calcs -- LOL will measure flow rat+ head again r anyway --its long term project ,after i can house built turbine for that is £1200 -- assuming 300 days of runnning --that,s still £2234 pr annum(0.16 elec cost) -so still looks viable ,if using it all ,and winter there will be no shortage of water time and more study will tell Edited November 5, 2019 by scottishjohn
SteamyTea Posted November 5, 2019 Posted November 5, 2019 I like picohydro, and 2 kW is a useful amount of power. Stick 4 kWh of battery storage on it, that will give you 6 kW, so a usable amount of power. You can run a kettle, a kW induction hob and the oven. The inverter for that lot will be £1500 though.
scottishjohn Posted November 5, 2019 Posted November 5, 2019 (edited) i remember now 5kw. that was the possible out put for the bottom lake and different turbine--bigger but much less drop again if i sell that bit --iwon,t be doing it Edited November 5, 2019 by scottishjohn
scottishjohn Posted November 5, 2019 Posted November 5, 2019 Just now, SteamyTea said: I like picohydro, and 2 kW is a useful amount of power. Stick 4 kWh of battery storage on it, that will give you 6 kW, so a usable amount of power. You can run a kettle, a kW induction hob and the oven. The inverter for that lot will be £1500 though. still much shorter payback than solar+ don,t see a shortage of water in scotland --maybe sun --but not rain . long way before we there .--but better to plan now for where things would go if i did do it 1
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