Half a croissant, on a plate, with a sign in front of it saying '50c'
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Solar Dam

Thermo-syphon Driven Micro Hydro Solar
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A solar through collector, is installed alongside a dam from bottom to top on both sides of the dam. The cold water from the dam has just lost its head kinetic energy through the turbine, but it is not wasted! The solar collector is fed by this cold water at the bottom of the dam. On a good sunny day the solar through collector with its U shaped parabolic mirors is able to heat water at and above 300° celsius - 572° F, but we don't need all this heat... we need only a small enough temperature differential to activate the thermo-syphon effect (hot water goes up - cold goes down).

This setting is for someone with a small personal dam,no industrial production is intended here, the heat will both lift the water back at the top of the Dam, because the solar collector is arranged along the gentle hill from the bottom to the top of the dam, and will serve the house with hot water. Electricity is produced at the pace of the solar through during the day, it is the thermo-syphon effect wich define the pace of the water running through the collector wich in turns determines the speed at which the micro hydroturbine operates. loop again baby!

This Solar Dam Water Loop is inactive at night, anyway the water loop is not drained, the level of water in the solar through equalize with the level in the dam, as you can see then you only need to heat it up again gently with the sun to activate the loop again and again.

I see an environmental drawback: heating the dam waters might modify biological life to favor more tropical species :)

Anyway I'm ready for the world climate change. And yes, we have a battery bank and a hot water tank for the night thanks!

Feel free to enhance my setup with any renewable toy you could think of, but please just mention available technology. Thanks for your help.

pilottage, Apr 24 2006


       How much head do you think the thermo-syphon will give you?
Ling, Apr 24 2006

       Head and Flowrate of the syphon are determined byt he total lenght of the solar trough collector - the longer the hotter the higher head you can reach.   

       It also depends of the intial cold water temperature.
pilottage, Apr 24 2006

       This bun smells lovely!   

       You could consider sandwiching Peltier modules between the downflow (cold) pipe and the upflow (warm) pipe as an expensive alternative to turbines.   

       Mmmmmm, sandwiches.
7ennyn, Apr 28 2006

       I don't understand how the thermo-siphon effect will get water back to the top of the dam. Hot water would just mix with cool water, and in any case would not rise through air. Hot water doesn't expand much so it won't rise.
sninctown, Apr 28 2006

       From memory, changing water from 4C to 44C gives about 1% expansion, and from 4C to 64C about 3% expansion.   

       A U tube with 10m of water at 4C in one side, and 10m of 64C water in the other side will stabilise so that the water in the hot side is about 300mm higher than the cold side.
300mm of head is not enough to lift it to the top of the dam.
But if the U tube is closed, with no air inside (becoming a circuit), then the water will circulate as long as one side is hot, and the other is cold.

       I think [pilottage] is expecting to break the siphon curcuit, and still have the water lift itself up to the top of the dam.
Ling, Apr 29 2006

       if you could have a solar collecter be large enough to super heat a nozzle that would produce steam then you would have some serious output. but it doesnt matter how hot the watter gets as long as its just a little bit warmer than the cold side. because the cold pulls as much as the heat lifts. you could even work snowmelt to your advatage in this system.
chickenninja, Aug 29 2007


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