Dominic:
The energy from the "turbine" comes from the potencial energy in the upper tank just to the time that tank is empty. Afterwards, nothing to do: the energy transformed in the turbine could be theoretically used by a while and you must forgot the case. Carlos ----------------------------------------- ----- Original Message ----- From: "ReadFamily" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 01, 2005 10:44 AM Subject: [microhydro] Confused about potential energy. > > > > I was thinking about the pumped water storage idea and then started to > think about the energy in the system. > > If there is a full tank at the top and an empty tank at the bottom then > the potential energy in the system is mgh (mass of water x gravitational > constant x height difference). > > So if you let the water flow from top tank to bottom tank through a simple > pipe then the potential energy is gone. (assuming bottom tank is at height > 0). > > Now put the water back into the top tank and this time put a turbine in > the pipe. The water flows from the top tank to the bottom tank and power > is generated by the turbine and extracted from the system. But the > difference in potential energy in the system is the same. All the water > from the top is now in the bottom. Where did the energy that was extracted > from the system by the turbine come from? > > I'm sure that the answer is somewhere in the statement in the first case > where the water flows through a simple pipe. The potential energy in the > system has changed - so where did the energy go? I dont know. > > Dominic Read > Georgia, USA. > > > > [Non-text portions of this message have been removed] > > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who > provides us with free email group services. The microhydro-group does not > endorse products or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> What would our lives be like without music, dance, and theater? Donate or volunteer in the arts today at Network for Good! http://us.click.yahoo.com/TzSHvD/SOnJAA/79vVAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
