Power from the pipes!

[Mighty AC]

Consider again the idea of one water droplet falling. Imagine without the turbine it falls a height h, turning its energy into 0.5mv^2 as before. Now imagine that half way down the drop, it instead hits a turbine blade, essentially bringing the water to rest as the kinetic energy is transferred to the turbine (this is a decent approximation for how a turbine works). Then the water droplet falls out the bottom of the turbine and falls the rest of the way, from height 1/2 h, ending up hitting the bottom with only half as much energy.

Assuming the turbine is calibrated to extract all of the kinetic energy, would the head pressure provided by the tower then be calculated by the height of the turbine? Let's say a ball shaped tank with a diameter of 30 feet sits on a 90 ft high vertical pipe with the turbine in between. If I understand what you're saying the tower would provide 39 psi (0.433 psi/ft) of constant pressure until the tank emptied. However, without the turbine, the tank would provide a max of 52 psi that steadily diminished as the tank empties.

What if the turbine was placed at the base of the vertical pipe? Would the tower have essentially zero head pressure?

[Derek 2.0]

Pressure on the mains is maintained at a level well above what eventually goes into your house to be ready for demand changes such as when everybody is in the shower in the am, or when they are sleeping at night. When you are not using your shower that unused flow could spin a wheel to make power.

I thought you said you understood the concept

When I'm not using my shower, both pressure and flow become static.......hence your wheel won't spin to make power.

[On Guard for Thee]

I thought you said you understood the concept

When I'm not using my shower, both pressure and flow become static.......hence your wheel won't spin to make power.

When you are not using your shower thousands of others are. Do you actually think water flow in a city like Portland actually ever comes to a halt.

[Derek 2.0]

When you are not using your shower thousands of others are. Do you actually think water flow in a city like Portland actually ever comes to a halt.

And when thousands of other showers are in use, system wide, the pressure will either drop or require additional energy (in the form of pumps and compressors) to make up for the drop in pressure.......and you want to generate energy, by using more energy (pumps/compressors) or accept a further drop in system pressure, which further strains the entire system.........So in effect, you'll create some energy by restricting water flow throughout your system at peak times.......

[On Guard for Thee]

And when thousands of other showers are in use, system wide, the pressure will either drop or require additional energy (in the form of pumps and compressors) to make up for the drop in pressure.......and you want to generate energy, by using more energy (pumps/compressors) or accept a further drop in system pressure, which further strains the entire system.........So in effect, you'll create some energy by restricting water flow throughout your system at peak times.......

Nope, you just have the generators freewheel when the folks get in the shower and the pressure starts to drop a bit. Simple.

Edited February 24, 2015 by On Guard for Thee

[Derek 2.0]

Nope, you just have the generators freewheel when the folks get in the shower and the pressure starts to drop a bit. Simple.

Yeah, and the pressure drops even further as it goes through your freewheeling generators turbines.......like I said above

[On Guard for Thee]

Yeah, and the pressure drops even further as it goes through your freewheeling generators turbines.......like I said above

Not when they are freewheeling.

[Derek 2.0]

Not when they are freewheeling.

Yeah, they do.......reread the article in the OP and Bonam's post

[On Guard for Thee]

Yeah, they do.......reread the article in the OP and Bonam's post

I have. Talk about babbling nonsense.

[Bonam]

Assuming the turbine is calibrated to extract all of the kinetic energy, would the head pressure provided by the tower then be calculated by the height of the turbine? Let's say a ball shaped tank with a diameter of 30 feet sits on a 90 ft high vertical pipe with the turbine in between. If I understand what you're saying the tower would provide 39 psi (0.433 psi/ft) of constant pressure until the tank emptied. However, without the turbine, the tank would provide a max of 52 psi that steadily diminished as the tank empties.

What if the turbine was placed at the base of the vertical pipe? Would the tower have essentially zero head pressure?

Roughly, my explanation above serves as a very rough approximation to a real turbine at best, illustrating the basic physics involved. A real turbine is more complex, but the pressure drop across it would usually be rated by the manufacturer and may depend on many factors including flow rate, the pressure at the turbine inlet, the temperature of the working fluid, etc. In general, a turbine will not remove ALL of the kinetic energy from a fluid but only a fraction of it, since the fluid still needs to exit the turbine. But in all cases, the pressure drop across the turbine will not be zero, if any energy is extracted from the fluid, it will leave the turbine with a lower pressure than it entered it with, and that will propagate through the rest of the system downstream.

(I assume you meant a tank with 30 foot height above a 90 ft pipe, rather than diameter)

A bit more info on hydro turbines:

http://en.wikipedia.org/wiki/Water_turbine

Edited February 24, 2015 by Bonam

[On Guard for Thee]

Yeah, they do.......reread the article in the OP and Bonam's post

Its similar to electricity. The voltage in those wires running along your street is much higher than the 240 volts that eventually enter your house. Thats to offset line loss. Thats the way it has always been done, and for good reason. However we now know we could also siphon off some the front end without adversely affecting the tail end, since demand fluctuates so much.

[Derek 2.0]

Its similar to electricity. The voltage in those wires running along your street is much higher than the 240 volts that eventually enter your house. Thats to offset line loss. Thats the way it has always been done, and for good reason. However we now know we could also siphon off some the front end without adversely affecting the tail end, since demand fluctuates so much.

How do we know that? A ~ 5 psi drop in water pressure within an already stressed waterworks, and further compounded at higher elevations, can be the difference between the fire department needing additional pumper trucks to pump water from hydrants, to other pumper trucks fighting a fire.......

[On Guard for Thee]

How do we know that? A ~ 5 psi drop in water pressure within an already stressed waterworks, and further compounded at higher elevations, can be the difference between the fire department needing additional pumper trucks to pump water from hydrants, to other pumper trucks fighting a fire.......

You dont pay attention very well do you. I have already mentioned all thats needed is a monitor that can drop the load off the main line gens. if the pressure hits a certain level, as when everybody goes for a shower, or a fire hydrant is brought online.

[Mighty AC]

Roughly, my explanation above serves as a very rough approximation to a real turbine at best, illustrating the basic physics involved.

Yes, I understand. The pipe turbines in the OP use about 12% of the head pressure, depending on flow rate.

(I assume you meant a tank with 30 foot height above a 90 ft pipe, rather than diameter)

Yes, but I did specify a round tank, so I should have been more clear and called it a sphere. Edited February 24, 2015 by Mighty AC

[Derek 2.0]

You dont pay attention very well do you. I have already mentioned all thats needed is a monitor that can drop the load off the main line gens. if the pressure hits a certain level, as when everybody goes for a shower, or a fire hydrant is brought online.

Ahh, so you'd just install further electrical controls in the system, and I assume a monitoring station that requires power 24/7, regardless as to if the turbine is functioning or not......and you'd just "shut down" the turbine during peak usage times, the times said turbine would generate the most potential power? But of course, even if you "shut down" the turbine, water still must pass through it, still creating a pressure loss throughout the system, due to a disruption in flow from a turbine that isn't generating power...........makes perfect sense in an bass aackwards type of way.......

[On Guard for Thee]

Ahh, so you'd just install further electrical controls in the system, and I assume a monitoring station that requires power 24/7, regardless as to if the turbine is functioning or not......and you'd just "shut down" the turbine during peak usage times, the times said turbine would generate the most potential power? But of course, even if you "shut down" the turbine, water still must pass through it, still creating a pressure loss throughout the system, due to a disruption in flow from a turbine that isn't generating power...........makes perfect sense in an bass aackwards type of way.......

Not a lot of pressure loss from a turbine with no torque on it. Seems to be working just fine in Portland. Maybe stick to posting happy faces and leave science to others.

[Derek 2.0]

Not a lot of pressure loss from a turbine with no torque on it. Seems to be working just fine in Portland. Maybe stick to posting happy faces and leave science to others.

Again, you need to reread the OP or Google fluid mechanics......

[TimG]

Again, you need to reread the OP or Google fluid mechanics......

The poster is either a troll who likes provoking people or an idiot who has no interest learning.

[Wilber]

I don't see the confusion here. The amount of water stored in reservoirs is dictated by demand. Usage varies widely depending on the time of day and season and so does the precipitation needed to fill them. Reservoir capacity and head pressure is dictated by periods of peak demand and the ability to fill those reservoirs is dictated by the supply available. There will be times where there is more than enough head pressure to maintain adequate pressure in the mains and some of it could be used to recover energy. Practical and cost efficient, I don't know but maybe worth a try.

[TimG]

There will be times where there is more than enough head pressure to maintain adequate pressure in the mains and some of it could be used to recover energy. Practical and cost efficient, I don't know but maybe worth a try.

The point you seem to be missing is pressure can only produce electricity if the water is moving. If there is less demand there is less water flowing which means less power. In the hypothetical extreme you could have no demand which means high pressure but no flow which means zero power. That is why tapping the water system for power makes zero sense. If you want hydro power build a dam on a river. It is cost effective and actually provides a net benefit. Edited February 25, 2015 by TimG

[Wilber]

The point you seem to be missing is pressure can only produce electricity if the water is moving. If there is less demand there is less water flowing which means less power. In the hypothetical extreme you could have no demand which means high pressure but no flow which means zero power. That is why tapping the water system for power makes zero sense. If you want hydro power build a dam on a river. It is cost effective and actually provides a net benefit.

Wind and solar aren't reliable methods of producing a constant amount of power but both are useful. Most of the time there will be an excess of energy stored in the reservoirs. Think regenerative braking in vehicles. High pressure at low flow produces the same amount of power as low pressure at high flow. Think ohms Law.

[Derek 2.0]

I don't see the confusion here. The amount of water stored in reservoirs is dictated by demand. Usage varies widely depending on the time of day and season and so does the precipitation needed to fill them. Reservoir capacity and head pressure is dictated by periods of peak demand and the ability to fill those reservoirs is dictated by the supply available. There will be times where there is more than enough head pressure to maintain adequate pressure in the mains and some of it could be used to recover energy. Practical and cost efficient, I don't know but maybe worth a try.

Yet, from the article within the OP:

Unlike other forms of green power, like solar or wind, the Lucid system can produce power at any time of the day because the water is always flowing. The only hitch is that the turbines can only produce power where water is naturally flowing downward with gravity. Lucid’s pipes contain sensors that can monitor the quality of the water flowing through the pipes, making them more than just a power generating technology, which can be valuable just about anywhere.

Furthermore:

The LucidPipe Power System, which was developed in conjunction with Northwest Pipe Company, utilizes a patented, spherical, vertical axis turbine that recovers otherwise untapped energy in the form of excess head pressure in large, gravity-fed pipelines. One or more turbines can be installed inside sections of large-diameter (24” – 96”) steel water pipe to produce clean, reliable, low-cost electricity without affecting operations.

So the system can't be used in pressurized pipelines, but gravity fed systems, as clearly outlined already by myself and several others, fore decreasing pressure to generate energy, in a system that requires an energy source (to power pumps and compressors) is self defeating........

Now, with a large storm sewer, or gravity fed aqueducts (like what supplies Southern California) as mentioned by Mighty AC, the design might have merit, only though if you could determine if the cost of retrofitting old systems would result in viable returns in energy production.

Edited February 25, 2015 by Derek 2.0

[TimG]

Wind and solar aren't reliable methods of producing a constant amount of power but both are useful.

Both take free energy from the sun and convert to electricity. The analogy does not apply to man made water systems.

Most of the time there will be an excess of energy stored in the reservoirs.

You don't understand the nature of potential energy. Potential energy is not wasted if it is not used. This makes it completely different from solar/wind or even regenerative breaking where energy converted to heat during breaking is converted to electricity instead.

High pressure at low flow produces the same amount of power as low pressure at high flow.

The flow needs to be matched to the demand. If energy is siphoned off then extra flow must be provided to keep the pressure up. This extra flow would be treated water that would be sent straight to the sewer.

[Wilber]

Yet, from the article within the OP:

Furthermore:

So the system can't be used in pressurized pipelines, but gravity fed systems, as clearly outlined already by myself and several others, fore decreasing pressure to generate energy, in a system that requires an energy source (to power pumps and compressors) is self defeating........

Now, with a large storm sewer, or gravity fed aqueducts (like what supplies Southern California) as mentioned by Mighty AC, the design might have merit, only though if you could determine if the cost of retrofitting old systems would result in viable returns in energy production.

All systems are pressurized but I agree that gravity is the force being used to produce the energy. Whether it comes from a natural reservoir or is pumped into a storage facility is not relevant. The question is, how much energy can we can we recover from the system beside that which is just being used to supply the water.

[Derek 2.0]

All systems are pressurized but I agree that gravity is the force being used to produce the energy. Whether it comes from a natural reservoir or is pumped into a storage facility is not relevant. The question is, how much energy can we can we recover from the system beside that which is just being used to supply the water.

Well clearly a gravity system (be it potable or drainage) is pressurized so much as atmospheric+, but yes, a cost-benefit analysis would be a must........For example, such a system used for storm water runoff in the North shore, Westwood or Heritage Mountain could be viable in the fall/winter/spring months, but how muchy to install and maintain???