TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) On edit. Let me qualify that. At times other than peak demand, there is excess energy stored in the system. At peak, full main pressure might be required to provide enough flow to meet demand.Nope. You are assuming the energy needed to maintain the system is a constant. It is not. If there is less demand less energy is needed to keep the system within operating parameters. There is no excess energy that can be used for other purposes. I got a question for you: why do you believe engineers would be so stupid as to design a water system that wasted energy? Don't you think they would do whatever they could to reduce wasted energy to as close to zero as possible? That is what they do with the electrical system. Edited February 25, 2015 by TimG Quote
On Guard for Thee Posted February 25, 2015 Report Posted February 25, 2015 You need higher pressure to provide higher speed in a given diameter pipe. Because we have to reduce main pressure which means reducing flow, there is excess energy stored in the system that is not required to supply water. On edit. Let me qualify that. At times other than peak demand, there is excess energy stored in the system. At peak, full main pressure might be required to provide enough flow to meet demand. And thats when you take the load off the generators. Easy to do with a few pressure sensors and switches. Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 Nope. You are assuming the energy needed to maintain the system is a constant. It is not. If there is less demand less energy is needed to keep the system within operating parameters. There is no excesss energy that can be used for other purposes. The pressure required to operate the system needs to be within a certain range. Whether that range can be maintained will depend on demand. The pressure is determined by reservoir level. Except under extreme demand, that full pressure is not required to operate the system. When there is excess pressure, the water can be diverted through the turbine to provide power, this will result in a pressure drop but as long as it remains above the minimum required, it can drive the turbine. If it drops below that minimum, you either decrease the load on the turbine or bypass it completely. Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) Then there is excess pressure, the water can be diverted through the turbine to provide power, this will result in a pressure drop but as long as it remains above the minimum required, it can drive the turbine.Doing this would require that potable water be wasted to maintain the pressure. This in turn, would increase the energy required to pump water into the reservoir. There is no scenario where you can take energy out of the system without paying a cost somewhere else. Edited February 25, 2015 by TimG Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 Doing this would require that potable water be wasted to maintain the pressure. This in turn, would increase the energy required to pump water into the reservoir. There is no scenario where you can take energy out of the system without paying a cost somewhere else. No it doesn't. All you do is divert the water from the main, through the turbine and back into the main. If a down stream pressure switch senses low pressure, it just opens a valve and lets the water continue straight down the main, bypassing the turbine section. I suspect the guys who spent a ton of money developing this system have a pretty good idea of the basic principles involved. Whether it makes sense economically is yet to be determined. Quote "Never trust a man who has not a single redeeming vice". WSC
On Guard for Thee Posted February 25, 2015 Report Posted February 25, 2015 No it doesn't. All you do is divert the water from the main, through the turbine and back into the main. If a down stream pressure switch senses low pressure, it just opens a valve and lets the water continue straight down the main, bypassing the turbine section. I suspect the guys who spent a ton of money developing this system have a pretty good idea of the basic principles involved. Whether it makes sense economically is yet to be determined. From what I read about the test phase in Portland they dont bother with a bypass. The gen. can just switch off the load if need be but so far it seems to be producing 24-7 without a hitch. Quote
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) I suspect the guys who spent a ton of money developing this system have a pretty good idea of the basic principles involved. Whether it makes sense economically is yet to be determined.The system they designed has absolutely no connection with what you are describing. In the link they acknowledge that without water moved by mother nature to a higher elevation they cannot produce power. IOW - they are doing the same as putting hydro dam in front of a mountain reservoir. Lets put this another way: if it was possible to generate power by building a water tower and attaching turbines to the outlet they would have done this decades ago and used the power to run the pumps that fill the tower. The most plausible explanation for this oversight is that there is no waste power to use despite your apparent belief in perpetual motion machines. Edited February 25, 2015 by TimG Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 (edited) The system they designed has absolutely no connection with what you are describing. In the link they acknowledge that without water moved by mother nature to a higher elevation they cannot produce power. IOW - they are doing the same as putting hydro dam in front of a mountain reservoir.Lets put this another way: if it was possible to generate power by building a water tower and attaching turbines to the outlet they would have done this decades ago and used the power to run the pumps that fill the tower. The most plausible explanation for this oversight is that there is no waste power to use despite your apparent belief in perpetual motion machines. Why are they doing it then? The purpose of a water system is to deliver water, not produce power but if it can generate some power on the side, it's a bonus. No system that has to operate over a wide range of conditions can be equaly efficient under all of them. We do a ton of things we didn't do decades ago, it's called progress, innovation and adapting to a changing world. Edited February 25, 2015 by Wilber Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) Why are they doing it then? The purpose of a water system is to deliver waterPortland has some water mains coming down from mountain reservoirs. They put turbines on these pipes because there is likely more kinetic energy than needed to distribute the water. They could have captured the same power by building a dam on the reservoir. This is a case where there is wasted energy that can be tapped thanks to mother nature. This does not apply to any system where water has to be pumped by man into a reservoir. No system that has to operate over a wide range of conditions can be equaly efficient under all of them.And in almost all of those cases the "waste" cannot be harvested because the waste it due to unavoidable heat losses in the various components. The water system is not like a breaking system where kinetic energy was deliberately converted to heat because they had no other options until they figured out how to convert it to electricity instead. With the water system if the demand is low the energy required to keep it stable drops so there is no 'waste energy' to be captured. Edited February 25, 2015 by TimG Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 (edited) Tim. Say you need to maintain a reservoir level that can keep 300 PSI in the mains to meet peak requirements but 75% of the time only 200 PSI is required to provide adequate supply. Use a turbine to drop the pressure 100 PSI. When we put a water wheel in a stream to provide power to drive machinery, all the water still ends up going down the stream, just at a reduced speed. Edited February 25, 2015 by Wilber Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) Tim. Say you need to maintain a reservoir level that can keep 300 PSI in the mains to meet peak requirements but 75% of the time only 200 PSI is required to provide adequate supply. Use a turbine to drop the pressure 100 PSI. When we put a water wheel in a stream to provide power to drive machinery, all the water still ends up going down the stream, just at a reduced speed.The pressure is constant. What varies is the flow required to meet the demand. If you add a turbine you would drop the pressure below operating spec. You could increase the flow to compensate, however, that would waste potable water. Edited February 25, 2015 by TimG Quote
On Guard for Thee Posted February 25, 2015 Report Posted February 25, 2015 The pressure is constant. What varies is the flow required to meet the demand. If you could add a turbine you drop the pressure below operating spec. You could increase the flow to compensate, however, that would waste potable water. There is a reason you have a prv between the mains and your tap. Some of that differential can be used for other things depending on demand. Installing a few turbines into an already constructed flow system is a hell of a lot cheaper than building a new dam by the reservoir. As Wilber has poited out, its called progress. Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 The pressure is constant. What varies is the flow required to meet the demand. If you add a turbine you drop the pressure below operating specs but you could increase the flow to compensate but that would waste potable water. You don't use it to lower pressure below operating specs you use it to reduce pressure in excess of operational requirements at a particular time. Water systems are required to maintain head pressures at peak demand. Most of the time that level of pressure is not reqired. You stilll don't seem to grasp the concept that while engineers may try and make a system as efficient as they can, its purpose is to deliver water, not create or conserve energy. Extracting some of the excess energy that has been stored but not required to deliver adequate water supply is just part of increasing the systems efficiency. Quote "Never trust a man who has not a single redeeming vice". WSC
overthere Posted February 25, 2015 Report Posted February 25, 2015 We have missed a couple of variables present in the water supply in municipalities. One is the loss of pressure because of the friction of the water inside the pipes, which increases as the pipe diameter decreases sequentially on the way to individual house services. This energy is converted to heat, heat in the water. The other is line loss of water and pressure along the way. There is always loss of water volume and pressure along the way because over time there are always leaks. Quote Science too hard for you? Try religion!
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) You stilll don't seem to grasp the concept that while engineers may try and make a system as efficient as they can, its purpose is to deliver water, not create or conserve energy.You don't seem to understand that water systems don't waste energy because energy costs money. For that reason alone you can be sure that there is no 'excess energy' that can be tapped. Think about it: if your way of thinking had any merit they energy would be consumed even if no water was flowing. This is makes no sense. If no water is flowing there is no consumption of energy (other than minor parasitic losses). The nice thing about water reservoirs is energy can be stored until it is needed. Adding turbines to generate electricity will only consume this stored energy. Once you factor in the energy needed to fill the reservoir you will find yourself consuming more energy than you produce. As I said before: you can't get something for nothing. Edited February 25, 2015 by TimG Quote
On Guard for Thee Posted February 25, 2015 Report Posted February 25, 2015 You don't seem to understand that water systems don't waste energy because energy costs money. For that reason alone you can be sure that there is no 'excess energy' that can be tapped. Think about it: if your way of thinking had any merit they energy would be consumed even if no water was flowing. This is makes no sense. If no water is flowing there is consumption of energy (other than minor parasitic losses). The nice thing about water reservoirs is energy can be stored until it is needed. Adding turbines to generate electricity will only consume this stored energy. Once you factor in the energy needed to fill the reservoir you will find yourself consuming more energy than you produce. As I said before: you can't get something for nothing. You arent getting something for nothing. You are simply recouping the something you have already built in, but doe always need. You could do a similar thing with the electrical grid. There is a hell of a lot more voltage on the mains than what comes into your house. The extra is there to be ready when everybody hits the light switch in the evening. Prior to that time, there is surplus. Quote
Wilber Posted February 25, 2015 Report Posted February 25, 2015 (edited) It's not about getting something for nothing, the energy is already stored in the reservoir but you don't need all of it to deliver the water. The energy isn't in the water, it is in the force it exerts. All the turbine does is use pressure in excess of that required at the time. Why would you think head pressure in the reservoir is always perfectly matched to demand? Btw. Hydro electric systems are all about getting something for nothing. Edited February 25, 2015 by Wilber Quote "Never trust a man who has not a single redeeming vice". WSC
Wilber Posted February 25, 2015 Report Posted February 25, 2015 (edited) We have missed a couple of variables present in the water supply in municipalities. One is the loss of pressure because of the friction of the water inside the pipes, which increases as the pipe diameter decreases sequentially on the way to individual house services. This energy is converted to heat, heat in the water. The other is line loss of water and pressure along the way. There is always loss of water volume and pressure along the way because over time there are always leaks. True, nothing is 100% efficient and a turbine would just be one more source of friction, but instead of that friction just generating heat, it would be producing power as well. As long as it doesn't degrade system pressure below that required to maintain supply, it is just increasing the efficiency of the system. With today's computers, it wouldn't be difficult to regulate turbine operation to maintain a constant pressure above that required to operate the system, either by regulating load on the turbine or bypassing it partialy or completely when greater main pressures are required. Edited February 25, 2015 by Wilber Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 25, 2015 Report Posted February 25, 2015 (edited) The energy isn't in the water, it is in the force it exerts.Energy is a function of FORCE and DISTANCE. If nothing moves you have no energy release or storage. To get the energy out of the reservoir you must release the water which requires that it be replaced which takes energy. With a hydro dam the sun provides the energy to replace the water. With a water tower man must provide the energy. Btw. Hydro electric systems are all about getting something for nothing.Not true. The sun evaporates the water in the ocean which is then carried on the land with wind where it falls as rain. The rain collects in rivers which can be blocked by dams. The excess energy in this system is the energy that would normally go into adding kinetic energy to the water. With man made reservoirs it takes energy to pump water into them. This means that there can be no net production of electricity once you factor in the energy consumed filling the reservoir. This is a simple energy conservation problem. You cannot get more energy out of system than is put into it. In a man made system all input energy comes from man. Once you factor in conversion losses you cannot possibly produce more energy than is put in. Edited February 25, 2015 by TimG Quote
On Guard for Thee Posted February 25, 2015 Report Posted February 25, 2015 Energy is a function of FORCE and DISTANCE. If nothing moves you have no energy release or storage. To get the energy out of the reservoir you must release the water which requires that it be replaced which takes energy. With a hydro dam the sun provides the energy to replace the water. With a water tower man must provide the energy. Not true. The sun evaporates the water in the ocean which is then carried on the land with wind where it falls as rain. The rain collects in rivers which can be blocked by dams. The excess energy in this system is the energy that would normally go into adding kinetic energy to the water. With man made reservoirs it takes energy to pump water into them. This means that there can be no net production of electricity once you factor in the energy consumed filling the reservoir. This is a simple energy conservation problem. You cannot get more energy out of system than is put into it. In a man made system all input energy comes from man. Once you factor in conversion losses you cannot possibly produce more energy than is put in. Very simple. You are taking back excess energy already invested in the system. Especially when gravity is available. Quote
Wilber Posted February 26, 2015 Report Posted February 26, 2015 Energy is a function of FORCE and DISTANCE. If nothing moves you have no energy release or storage. To get the energy out of the reservoir you must release the water which requires that it be replaced which takes energy. With a hydro dam the sun provides the energy to replace the water. With a water tower man must provide the energy. The water doesn't stop flowing, we just remove excess energy that is not required to get it to its destination. If we put a water wheel in a stream, all the water eventually gets to its destination because there is still enough energy to get the water there, in spite of the fact we have removed some. So far we haven't been able to develop any machine that is 100% efficient. We couldn't extract all of the energy from a moving column of water if we wanted to. Not true. The sun evaporates the water in the ocean which is then carried on the land with wind where it falls as rain. The rain collects in rivers which can be blocked by dams. The excess energy in this system is the energy that would normally go into adding kinetic energy to the water. With man made reservoirs it takes energy to pump water into them. This means that there can be no net production of electricity once you factor in the energy consumed filling the reservoir. This is a simple energy conservation problem. You cannot get more energy out of system than is put into it. In a man made system all input energy comes from man. Once you factor in conversion losses you cannot possibly produce more energy than is put in. As far as we are concerned, it is something for nothing. Once the facility is built, weather does the rest, all we have to do is maintain the system. This is an energy recovery problem. Not all the energy put into the system is required to move the water because of the need to have higher pressures during peak demand. Most of the time, those higher pressures are not required. You say this isn't like regenerative braking I disagree. It takes a certain amount of energy to get a vehicle up to speed and keep it there. We recover some of that energy by recovering the kinetic energy stored in the vehicle when it slows down. Why do you think a moving column of water is any different? Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 26, 2015 Report Posted February 26, 2015 The water doesn't stop flowing, we just remove excess energy that is not required to get it to its destination.I really don't understand why you cannot understand the basics of conservation of energy. The only energy in the system is the energy used to pump the water into the tower. The only energy that needs to be released is the energy required to get the water to its destination. Unlike a river which has lots of moving water that has no purpose there is no extra water motion required to move water through a water system. The system only needs to let out exactly the amount of water required to meet the demand. There is no magical pool of unnecessary kinetic energy that can harvested. If there is then the engineers who designed the system did not do their job. Quote
Wilber Posted February 26, 2015 Report Posted February 26, 2015 (edited) I really don't understand why you cannot understand the basics of conservation of energy. The only energy in the system is the energy used to pump the water into the tower. The only energy that needs to be released is the energy required to get the water to its destination. Unlike a river which has lots of moving water that has no purpose there is no extra water motion required to move water through a water system. The system only needs to let out exactly the amount of water required to meet the demand. There is no magical pool of unnecessary kinetic energy that can harvested. If there is then the engineers who designed the system did not do their job. The energy required to pump the water up to the tower is in excess of that needed to get it to its destination. This is about recovering some of that excess or in the case of a mountain reservoir, getting some of the energy nature and gravity gave us. Edited February 26, 2015 by Wilber Quote "Never trust a man who has not a single redeeming vice". WSC
TimG Posted February 26, 2015 Report Posted February 26, 2015 (edited) The energy required to pump the water up to the tower is in excess of that needed to get it to its destination. This is about recovering some of that excess or in the case of a mountain reservoir, getting some of the energy nature and gravity gave us.There is NO excess. No matter what the demand the system only needs to release exactly the amount of energy required to get the water to its destination. In the extreme case of no demand the system does not need to release any energy. The point you seem to be missing is it is very easy to control the amount of energy released by limiting the volume of water released. This gives the designers precise control over the amount of energy released at any given time. They do not need to waste energy. Edited February 26, 2015 by TimG Quote
Wilber Posted February 26, 2015 Report Posted February 26, 2015 There is NO excess. No matter what the demand the system only needs to release exactly the amount of energy required to get the water to its destination. In the extreme case of no demand the system does not need to release any energy. The point you seem to be missing is it is very easy to control the amount of energy released by limiting the volume of water released. This gives the designers precise control over the amount of energy released at any given time. They do not need to waste energy. Reservoir levels are dictated by the quantity needed to supply the system, not by the amount of pressure required in the mains There is excess energy stored in the system. Quote "Never trust a man who has not a single redeeming vice". WSC
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