WO2006085782A1 - Re-circulating water in close-looped hydropower system - Google Patents

Re-circulating water in close-looped hydropower system Download PDF

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Publication number
WO2006085782A1
WO2006085782A1 PCT/PH2005/000015 PH2005000015W WO2006085782A1 WO 2006085782 A1 WO2006085782 A1 WO 2006085782A1 PH 2005000015 W PH2005000015 W PH 2005000015W WO 2006085782 A1 WO2006085782 A1 WO 2006085782A1
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water
reservoir
main
pressure
penstock
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PCT/PH2005/000015
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French (fr)
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Jose Ching
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Jose Ching
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03BMACHINES OR ENGINES FOR LIQUIDS
    • F03B17/00Other machines or engines
    • F03B17/005Installations wherein the liquid circulates in a closed loop ; Alleged perpetua mobilia of this or similar kind
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05BINDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2240/00Components
    • F05B2240/20Rotors
    • F05B2240/24Rotors for turbines
    • F05B2240/241Rotors for turbines of impulse type
    • F05B2240/2411Pelton type

Abstract

The present invention is a system wherein a controlled volume of water is re­circulated in a closed loop continually for the generation of electricity. The forces at work are: (1) mechanical force of water jets released directly from the main penstock after undergoing a high pressured water hammer compression; (2) the suction force created by the high vacuum after the huge volume expulsion of water from the main penstock; (3) gravitational force induced elevation heads; (4) pressure head of the pump; (5) the expanding inter-molecular cohesion force of the water column when the high pressured water jet is released from the main penstock. Water, being a compressible and elastic material can be subjected to very high pressured compression and low pressured expansion. This characteristic can be observed during a water hammer. In a complete valve "rapid closure", the water hammer pressure is directly proportional to the product of the water velocity

Description

RE-CIRCULATING WATER IN CLOSE- LOOPED HYDROPOWER SYSTEM

BACKGROUND Prominent traditional hydro-electric power plants are sited on great natural waterways. The Hoover Dam is on the Colorado River. The 18,000 MW Three Gorges dam power facility is on the mighty Yangtze River. The building of dam and elevating the height of the water surface to provide the stored volume and increase the potential head of the waterways constitute the main features of our present day hydropower plant. This can be a high head impulse type - Pelton turbine-generator or a lower head reaction type such as the Francis turbine- generator and the propeller turbine-generator. Together with other mini hydropowers such as run of the river power plant and micro-hydropowers are all forms of "Flow Through System ". Flow through system means there is a river upstream water flowing down into a turbine-generator producing electricity, then flow out into a river downstream.

At present, hydropower is considered as one of the best, if not the best form of energy. It is clean and non-pollutive. It is relatively economical as it is being recycled by Mother Nature through the water cycle. No fossil fuel is used. No harmful gases are emitted into the atmosphere. These however has its limitations and shortcomings. First, it is limited only to sites where big natural waterways flow. These sites are usually in far flung area where the power transmission lines to the cities are not only expensive, but also causes power losses. Second, its operation is entirely dependent on the seasonal precipitation, such that its average annual output is only about 50% of the installed capacity. Third, building dam could inundate farmlands and it could carry heavy social costs. Fourth, the construction of the dam is very time consuming and technically difficult. And lastly, there is always the danger of dam failure that could have catastrophic consequences to lives and properties. PRESENT INVENTION

The present invention is a new system of hydropower. It is in a closed loop system, more specifically, it is a hydro-electric power system with a controlled volume of water re-circulating continually within. This system features powerful jets released directly from a main penstock immediately after undergoing a high water hammer pressure. This system also features a series of water supplemental pipes that draw water directly from the reservoir into the main penstock during the high vacuum phase- this after the expulsion of huge volume of water from the main penstock.

The present invention is a system that has several advantages over the existing systems. First, it uses a controlled volume of water to generate power in a recycling mode. It is a non " FLOW THROUGH SYSTEM " as described in page 1 , line 14. Second, site selection is very wide. It can be built adjacent to big load centers such as industrial or urban areas. The site can be a plain or a mountain plateau with slope and plain, provided the ground is bed-rocked. It should be away from earthquake fault line or active volcano. The site should also be near an abundant source of water either above ground or sub-terrain, fresh or saline. Third, there is no need to build elaborate trash rack. Fourth, the construction time is much shorter. Fifth, it is relatively less expensive.

This author has written a book entitled " Water Hammer - The Explosive Pressure-- A Guide to Renewable Hydropower ". The present invention is based on the studies and calculations presented in the book.

Water hammer is defined as the excess pressure ( above the normal hydraulic grade line pressure ) - brought about by the sudden change of water flow velocity in a closed pipeline. The highest water hammer pressure is created when the valve is in a " Rapid Closure " i.e., the valve closing time < 2 L /Cp , where L is the length of the pipeline and Cp is the celerity of the pressure wave in water which is about 1 ,470 m/s at 20° C. The KINETIC ENERGY possessed by the entire water column reach by the celerity in the pipeline is transformed into a high pressure energy. This pressure energy compresses the water and expands the wall of the conduit simultaneously. The compressed water pressure is known as water hammer pressure.

This stored pressure energy is subsequently released by the rapid opening of the same valve, enabling a re-transformation to kinetic energy. Thus a highly pressurized flow that possesses substantial kinetic energy jets out to impinge on the buckets of the Pelton turbine-generator to produce electricity. In all the following sample illustrations, we will be using fresh water as basis for calculations. At sea level, fresh water has a density of 1 ,000 kg/m3 and specific weight of 9.81 kn/m3 . If seawater is used ,the figure is about 3 % higher. The density then is 1030 kg/m3 and specific weight is 10.1 kn/m3. As a general rule, the thicker the steel pipe, the faster will the celerity be.

The formula for calculating the water hammer pressure is:

Ph = Dm V W p

Where Dm is the mass density of fresh water, term is 1 ,000 kg/m3.

V is the velocity of the flowing water inside the penstock in a steady state, unit is in m/s.

Wp is the pressure wave velocity or celerity inside the penstock, unit

Is in m/s.

For instance, a steady flow of water with velocity of 12m/s is rapidly closed by a valve. Assuming the Wp is 1 ,400 m/s, then the water hammer pressure in the pipe ( length of about 1 ,450 meters ) is calculated as:

Figure imgf000005_0001

= 1 ,000 kg/m3 ( 12 m/s ) ( 1 ,400 m/s ) = 16,800,000 ( kg • m/s2 ) ( 1/m2 ) = 16,800 ,000 n/m2 = 16,800 kpa in term of energy head, it is :

16,800 kpa/g = 16,800 kpa / 9.81 nτs-2 = 1,712 meters. This 1 ,712 meters of pressure head is much higher than the energy head possessed by the liquid in the original steady state of flow.

We solve for the velocity head of the original flow of 12 m/s : VeI2 /2g = 12 21 19.62 = 7.34 meters

The big disparity in the energy head, from the original head of 7.34 meters to the induced high pressure head of 1 ,712 meters is one of the basic features of this present invention.

The present invention has two types of category. The type I is an ELEVATED GRAVITY DEPENDENT SYSTEM. The type II is a PUMP PRESSURE HEAD INDUCED SYSTEM. THE TYPE I CATEGORY SYSTEM

Under the type I category are two different construction designs. Fig. 1 and Fig. 2 show the tower supported design, while Fig. 3 and Fig. 4 show the mountain slope supported design. In both designs, the principal structures and equipments are as follow:

A. An upper reservoir ( 1 ) of sufficient height and size;

B. Two upstream downflow penstocks ( 2 ) . In Fig. 1, they are vertical ; in figure 3 , they are inclined;

C. Air-compressored surge chamber ( 21 ), this absorbs and releases excess pressured water to and from the penstock. The air compressor is operated periodically to replace the air absorbed by surging water;

D. Horizontal convergence conduit ( 3 );

E. Gate valve ( 18 );

F. Two main penstocks ( 4 ) having length of 1 ,450 m. laid in a horizontal way that end inside the powerhouse;

G. Uni-direction motorized spherical valves ( 5 ) connected to the main penstock ( 4 ) ;

H. A Pelton turbine ( 7 ) with a shaft that is coupled to the main generator

( 8 ) which has inertial flywheels ( 8-A ) attached to maintain a constant speed, as shown in Fig. 10;

I. A tail reservoir ( 10 ) that receives the exhaust water inside the powerhouse ( 9 ) ; J. An outflow pipe ( 19 ) and an inflow pipe ( 20 ) , the outflow pipe drains the exhaust water from the tail reservoir by gravity to the cooling reservoir ( 17 ) outside the powerhouse ( 9 ) while the inflow pipe draws in water from the cooling reservoir back into the powerhouse and connects to the main pump ( 12 ) as shown in Fig. 11 ; K. A main pump ( 12 ) powered by a motor ( 13 ) of sufficient capacity to pump all the needed water back to the upper reservoir ( 1 ); L. A pump pipeline ( 14 ) of sufficient capacity that originates from the main pump and ends in the upper reservoir ( 1 ); M. A cooling reservoir ( 17 ) which can be a natural body of water or a man made structure , it is inter-connected with the tail reservoir inside the powerhouse ( 9 ) via the inflow pipe and the outflow pipe, it is also one of the sources of water for the water supplemental pipes ( 36-B );

N. Water supplemental pipes ( 36-A and 36-B ) supply the immediately needed water to the main penstock ( 4 ) to prevent damages that can be caused by the vacuum formations. When water hammered jets are released and pressure in the main penstock had dropped precipitously, water is drawn immediately to prevent vacuum formation. They are both controlled by check valves ( 37 and 39 ) which are laid below the main penstock; in this way, the check valves are closed when the spherical valve is closing and water hammer pressure is building up. Moment later, when the spherical valve is opened , water jet will burst out and a vacuum suction force opens the check valve to allow the rushing in of supplemental water and the cycle continues;

O. An open reservoir ( 38 ) which water source is the upper reservoir ( 1 ). It is placed at about 10 meters above the check valve ( 37 ) to provide the needed lower pressure head, a 10 meter head is less than the pressure head in the main penstock during compression causing the check valve to close, but is higher than that during the expansion causing the check valve to open ; P. A starting generator ( 15 ) of sufficient capacity to initiate the rotation of the spherical valves. This starting generator will be used as the power source when the system undergo maintenance; Q. Water replenishment pipe ( 16 ) shown in Fig. 12, it brings in water from nearby natural source to replace water lost through evaporation; R. The gate valve ( 18 ) controls the flow of water from the upstream conduit to the main penstock ( 4 ). It is closed when maintenance work is ongoing.

OPERATIONS OF THE MOTORIZED UNI-DIRECTION

SPHERICAL VALVE In Fig. 10 is shown the two spherical valves ( 5-A and 5-B ) that rotate in a uni-direction mode. It shows the horizontal Pelton turbine ( 7 ) with a vertical shaft coupled to the rotor of the main generator ( 8 ). Valve 5-A is in a fully opened position while the valve 5-B is in the fully closed position. Both valves have the same dimensions and are operated by motors that rotate continually.

From Fig. 6-A to Fig. 6-D are shown the spherical valve having outlet or orifice that occupies one fourth of the circumference of the sphere, as does the inlet orifice. In such a manner, the circumference is at any time divided into four equal sections; two parts that open up and two parts that close it down. The valves are opened in one second time interval and closed in the next one second time interval. The two valves have a frequency of one revolution per four seconds that make them 15 RPM valves. Their respective positions, i.e. , opening and closing are timed to be one second apart. Such that when valve 5-A is fully opened, valve

5-B is fully closed and vice-versa.

The size of the outlet and inlet orifices in relative to the circumference may have to be modified to ensure the exhaustion of the water hammer pressure in ready for the next cycle. Figs. 6-A to 6-D show the sequence of the spherical valve in its movements. At both sides of the sphere are two concave depressions. The depression increases the surface area of that section exposed to the increasing water hammer pressure as the valve closes.

The formula relating force to area and pressure is: F = P x A

Force = Pressure x Area ; n = n/m2 x m2

As the formula indicates, area is directly proportional to the force. The bigger the exposed area, the greater force it could receive. This condition would create an unbalanced force on the sphere. That is, a greater force would exert on the portion with the concave depression than on the part without the depression. And this unbalanced force helps to increase the overall rotating torque of the spherical valve. Thus a calculated lesser capacity motor may be use.

Fig. 7 is the frontal view of the spherical valve showing outlet orifice. The valve should be made of very strong steel material that would withstand the constant adverse dynamic forces of the water hammers.

The rotor in the main generator ( 8 ) should possess enough mass that its moment of inertia ( M • R2 ) is sufficiently increased to compensate for the pulsating jet energy mode. Thus the need to install flywheels. ( 8-A ) VOLUME OF THE COMPRESSED WATER COLUMN The formula for calculating the rate of compression R0 of water under high pressure is : Rc = - P / E v where P is the applied pressure, unit is in kpa. E v is the volume modulus of water. At 20 ° C , its 2.18 x 106 kpa.

In our specific penstock of 1 ,450 meters in length and one meter in inside diameter. At 20 ° C , it is subjected to a pressure head of 1,712 meters or pressure units of 1 ,712 x 9.81 kn / m 2 = 16,795 kpa. The rate of compression of water is:

R c = - P / E v = - 16,795 kpa/ ( 2.18 x 10 6 ) kpa

= - 0.0077

The pressure of 16,795 kpa will compress the water by 0.77 %. To arrive at the compressed volume, we multiply the original volume by 0.77 % which is 1 ,450 meters x 0.785 x 0.77 % = 8.76 m 3 . The length of the water column is shrunk by 8.76 m 3 / 0.785 m 2 = 11.16 METERS. The more compressed the water column, the higher is its stored POTENTIAL ENERGY.

THE FLOW PATH OF RE-CIRCULATING WATER OF

TYPE I CATEGORY - TOWER SUPPORTED SYSTEM

Fig. 1 is an elevation view of the present invention with a free standing tower supported reservoir. Fig. 2 is the plane view of the same. The water surface in the upper reservoir ( 1 ) is about 150 meters high from the middle line of the main penstock ( 4 ). The dimensions of this upper reservoir is 25 x 25 square meters with six meters in height. The reservoir is square in shape with rounded corners. It accommodates about 3,700 cubic meters of water. This reservoir serves as the water tank to the entire system. Water starts flowing down the two upstream down-flow pipes ( 2 ). These pipes are both three meters in inside diameter. These run the entire length of the tower. Before reaching the ground, both have out-branched pipes to the open reservoir ( 38 ) that feeds the water supplement pipes ( 36 ). At the meantime, the down-flow pipes continues to the datum line, then bend 90° outward from the tower in opposite directions. The ratio of the bend radius to the diameter of the pipe is five, i.e., R / D = 5. The water then flows onward passing by the air compressored surge chamber ( 21 ). This chamber serves as a space to absorb the surge water during the high head compression phase. It will however release the water during the low pressured expansion. The chamber also serves to protect the upstream conduits so much so that the immediate conduits such as the bend and down-flow pipe ( 2 ) can be made of less thicker steel, about 2.5 cm. thick. After passing the air compressored- chamber, water reaches a 20 meters long penstock with three meters in inside diameter. Water flows on to the convergence conduit ( 3 ). These conduits are about 50 meters long. From one end of three meters in inside diameter, the convergence conduits end in a one meter inside diameter orifice. Water now reaches the gate valves ( 18 ). The two gate valves shut off flow during maintenance. After the gate valves, water flows into the main penstock ( 4 ). These main penstocks have one meter in inside diameter. The thickness of which is about 15 cm.. The inside surface , including those of the fittings must be polished as smooth as possible . This is to lessen the frictional head losses. The length of both the main penstocks ( 4 ) are 1 ,450 meters. The pipes material should be a high 0.8 % carbon steel. The main penstocks end with the motorized spherical valves in operations 10 meters high inside the powerhouse ( 9 ). As water hammered jets burst out into the atmosphere to impinge on the Pelton turbine-generator, it gives the kinetic energy to generate electricity. The jets from both penstocks burst out in a rotational mode. The exhaust water now falls into the tail reservoir ( 10 ). This tail reservoir inside the powerhouse receives the total water volume ejected out from the main penstocks including the non-water hammered flow. The main bulk of water comes directly from the long main penstocks in addition to the water volume sucked in by the vacuum force from the supplemental water pipes that is sourced from the reservoirs ( 38 and 17 ).

From the tail reservoir ( 10 ), water is now channeled out of the powerhouse via the outflow pipe ( 19 ) by gravity into the cooling reservoir ( 17 ). Water is air cooled in the atmosphere and re-enter the powerhouse either by the inflow pipe ( 20 ) or by the water supplemental pipes ( 36-B ). Water entering through the inflow pipe flows to the pump ( 12 ) directly , as shown in Fig. 11, to be pumped up the upper reservoir ( 1 ) , thus COMPLETING THE CIRCULATION OF THE LOOP. Water entering through the water supplemental pipes ( 36-a & 36-b ) meanwhile flows into the main penstocks( 4 ) by forces of gravity and vacuum suction, thus COMPLETING THE CIRCULATION OF THE SUB-LOOP.

MODIFIED PRESSURE WAVE VELOCITY AT 20° C1 the speed of the pressure wave in water is 1 ,478 m/s. However, in an elastic pipe, it is modified by the stretching of the pipe walls. In this case, it is modified by steel material and its thickness of 15 cm.. Using the modified pressure wave formula:

MWp = Wp [ 1 / ( I + Ev - D / E . t ) ] 1 / 2 where Wp is the water pressure wave velocity at 20 ° C.

E v is the volume modulus of water which is 2.18 x 106 kn»m- 2 . E is the bulk modulus of the pipe material. For steel, it about

207 x 10 6 kn τn -2 .

D is the inside diameter of the pipe which in this case is one meter. t is the thickness of the pipe which in this case is 0.15 meter.

Then :

MWp = 1478 { 1 / [1 + (2.18 x 106 x 1) / ( 207 x 106 x 0.15 ) ] } 1/2 = 1478 [ 1 / ( 1 / 1+ 0.07 ) ] 1/2 = 1428.8 m/s The pressure wave in this specific pipe and water temperature of 20 ° C is

1428.8 m/s.

CALCULATIONS OF THE ENERGY EQUATION

From the water surface in the upper reservoir ( 1 ) to the out-flow through the spherical valve, the energy equation is : Z = ( V m2 / 2g ) + H TL

Where Z is the elevation head, which in this case is 150 meters.

V m 2 / 2g is the steady state velocity head of the main penstock (4) water that flow into the atmosphere.

HTL is the total of all head losses along the entire pipeline. Then: 150 = ( Vm 2 / 2g ) + H TL

From the computations presented in the book, the total head losses is about 17.62 Vm 2 / 2g ,

Therefore: 150 = ( 1 + 17.62 ) V m 2 / 2g Vm2 / 2g = 8.05 meter

V m = [ 2 ( 9.81 )( 8.05 ) ] 1'2

= 12.57 m/s.

The velocity of the water flow in the pipeline is 12.57 meters per second. When the spherical valve is closed in one second time, the water hammer pressure is : PH = Dm V W p = ( 1000 kg/m3 )( 12.57 m/s )( 1428.8 m/s ) = 17960 k ( kg« m/s2 )( 1/ m2 ) = 17960 k n ( 1/ m2 ) = 17960 kpa

In term of pressure head, it is 17960 / 9.81 = 1,830 meters. From a steady flow velocity head of 8.05 meters, the rapid closure of the spherical valve rams up the energy head to 1,830 meters high of pressure head. In the next second, the spherical valve rotates to a fully opened position. And in this entire second, pressurized out-flow possessing substantial kinetic energy is released into the atmosphere to impinge on the Pelton turbine-generator. This release of water jet is simultaneous with the abrupt decrease of pressure head in the penstock.

In Fig. 8 shows the projected chart of the water discharge. At T=O sec, the valve is closed, water is not flowing and the water hammer pressure inside the penstock is 1 ,830 meters. Then in the next second, the valve opens fully. At the time interval of T=O sec. to T=1 sec, the pressure head is dropping rapidly. The assumed head would be about 1 ,600 meters at the instant T=1 sec. It should be noted that it is not anymore the original head of 1 ,830 meters. The velocity head of water jet has the term :

H = V2 / 2g Then velocity = [ ( 2g ) H ] 1/2 ,

Assuming the instantaneous head is 1 ,600 meters at T= 1 sec. therefore: Vin* = [ 2g ( 1600 ) ]1'2 = 177 m/s.

The equation for instantaneous discharge at T= 1 sec:

Q inst = A V inst where A is the area of the pipe opening, unit is in m2

V inst is the instantaneous velocity, unit is in m/s.

For the given area and the instantaneous velocity of 177 m/s, the instantaneous discharge is : Q inst = ( 1 ) 2 ( 1/4 ) ( 177 ) = 0.785 ( 177 )

= 139 m3 /sec

The projected water discharge graph would approximate the curve of the formula: Y= 139(2X-X2) ; Given : Domain = [X | 0<X<2] where X is the time in seconds.

Y is the water discharge volume. Fig.8 charts this relationship.

For the second from T=0.5 sec. to T=1.5 sec, the discharge is highest and its power is greatest. By using integration to measure this water discharge :

Q

Figure imgf000013_0001

= {139[1.52-(1.53/3)]}~ {139[0.52-(0.53/3)]> Q = 127.46 m3 /sec From the equation of discharge, we solve for the average velocity:

Vave = Q / A = 127.46 / 0.785 =162.4 m/s Thus the average velocity head from T= 0.5 sec. to T= 1.5 sec. is

162.42/2g = 1,343.8 meters

To arrive at the approximate hydrodynamic power of the jet from T=0.5sec to T= 1.5 sec. , we use the formula for power :

Hydrodynamic power = Q Wsp Have/ 1000 ; unit is in kw. where Q is the discharge in one second, unit is in m 3/ s.

Wsp is the specific weight of water, unit is in newtons / m 3. Have is the average head of the water jet, unit is in meters. Hence, power = 127.46 ( 9810 ) ( 1342.8 ) / 1000

= 1,680,246 kw or 1680.2 MW.

Assuming a 90% efficiency turbine-generator, then the power generated is 1680.2 x 90% = 1512 MW.

If we calculate the power from the KINETIC ENERGY approach, we would have come up with the following equation : K. E. = 1/2 m v 2 where m is the mass of the water jet, unit is in kg. For 127.46 m3, the mass is 127,460 kilograms. v is the mean velocity of the water jet, unit is in m/s. In this case, it is 162.4 m/s . Hence : K. E. = 1/2 ( 127,460 ) ( 162.42)

= 1 ,680,800 kn»m This kinetic energy of 1 ,680,800 tovm is released in one second time, making the term 1 ,680,000 kn»m / sec. Since kn»m / sec. is equivalent to the term kw, therefore the power of 1 ,680.8 MW is about the same as the 1 ,680.2 MW we arrived at by using the hydrodynamic power equation.

POWER NEEDED TO PUMP WATER UP THE RESERVOIR IN TYPE I - TOWER SUPPORTED DESIGN SYSTEM

Fig. 9 shows the alternating water discharge curves of the two penstocks. From T= 1 sec. to T=2 sec, the total discharge of both penstocks was about 186.88 m3 /sec. This process sustains the continuous re-circulation of water for delivery of power to the turbine-generator. To pump back this volume of water up the reservoir ( 1 ) would require a pump and pipe of sufficient capacity. In this case, we have a 5 meters inside diameter pipe. It starts from the pump and ends up at the upper reservoir. The length is about 185 meters with two 90° bends. The elevation is about 155 meters. From the Principle Of Continuity, the energy equation for this pump line is : Hpump = Z + v2/2g + H TL where Z is the elevation head, unit is in meters. v2/2g is the velocity head of the water flow at the outlet of the pipe, unit is in meters.

HTL is the total frictional head loss in the pipe , unit is in meters. We first calculate for the velocity in the pump pipe line. The equation is:

V = Q / A = 186.88 / [ ( 5 2 ) ( 1 / 4 ) ] = 9.52 m/s Velocity head is therefore : 9.52212g = 4.62 meters. The total head loss due to frictions is about 0.26 v2 /2g , thus the head loss s 0.26 ( 4.62 ) = 1.2 meter. The head of the pump is then:

Hpump = 155 + 4.62 + 1.2 = 160 meters. and the Power required is:

Power of the pump = Q Wsp H / 1000 = 186.88(9810)(160) / 1000= 295MW At 90 % efficiency, the pump would need 327 MW of power. This plus about 10 MW of power for other equipments is to be deducted from the generated output of 1 ,512 MW and comes up with about 1 ,175 MW of transmittable electricity.

WATER REPLENISHMENT OF THE SYSTEM As shown in Fig. 12, on a periodic basis, the water replenishment pipe (16) draws in water from the natural source nearby to replenish the loss of water due to evaporation. This is done by flowing water into the cooling reservoir ( 17 ) .

A cooling reservoir ( 17 ) of sufficient capacity should be set up outside the powerhouse. It could be a natural body of water. The cooling system serves to cool the heated water that flow through the generator, the transformer and other auxiliary equipments. This cooling system uses atmospheric air as the main cooling agent. The heated water is carried out the powerhouse together with the exhaust water in the tail reservoir through the outflow pipe ( 19 ) to the cooling reservoir that is exposed to the atmospheric air for dissipation. The temperature of the cooling reservoir has to be monitored to prevent it from getting too high. In case of high temperature, other cooling methods may be applied.

MOUNTAIN SLOPE SUPPORTED DESIGN OF

THE TYPE I CATEGORY

In Fig. 3 and Fig. 4 are shown two perspectives of the present invention under the type I category- mountain slope supported design system. Fig. 3 is the elevation view while Fig. 4 is the plane view. The upper reservoir ( 1 ) is built on top of a stable plateau. The upstream down-flow penstocks ( 2 ) are inclined. It has the same elevation head of 150 meters high, both the upstream down-flow penstock ( 2 ) and the pump line ( 14 ) are longer than those of the tower supported design. The dimensions of the other principal pipes and structures are all similar. It has the same circulations, functions and operations described in the tower supported design of the same category. This mountain slope supported design system would have a slightly lower usable electricity produced due to its longer penstocks and pump line that cause higher frictional head losses. THE TYPE II CATECORY SYSTEM

The type II category system of the present invention differs from the type I category system on two distinct characteristics. First, it is built on low ground level. Second, the elevation head in type I is substituted by pressure head supplied from a motorized pump ( 25 ). These two features are the main differences. The operations of both types in producing electricity are however almost similar.

A type II category system of the present invention where the pump pressure head equals the type I system and where the dimensions of the main pipes and equipments are similar to the type I system, its usable electricity produced is bigger than the type I . Its because in type II system, a portion of the re-circulating water uses gravity to flow out to the main reservoir (22) for immediate re-circulation, while type I system has to pump all the water needed up to the upper reservoir (1) to complete the re-circulation. THE STRUCTURES & EQUIPMENTS OF THE TYPE II CATEGORY SYSTEM

On Fig. 13 is a diagram of the plane view of the type 1 1 system. It has the following structures and equipments :

A. A main reservoir ( 22 ). A man made or natural body of water which surface area is wide enough to also serve as a cooling reservoir; B. Entrance conduit (23 );

C. Starting generator ( 15 ), it supplies the initial power to the pump ( 25 ) and the spherical valves ( 5 );

D. Motorized pump ( 25 );

E. Convergence pipe ( 26 ) about 20 meters in length. F. Gate valves ( 27 ), these valves open / close the entrance of water flow into the main penstocks ( 4 ); G. Two 1,450 meters long main penstocks ( 4 ) with one meter inside diameter that end 10 meters higher inside the powerhouse ( 9 ); H. Pressure relief valves ( 28 ) set on a water release pressure of about 40 meters above the pump energy head in order to protect the pump.

Water hammer pressure surge that reaches this point collides with the pump pressure flow. That resultant upsurge in pressure would push open the pressure relief valve allowing the excess pressurized water to flow out of the main penstock and into the main reservoir ( 22 ); I. Air cushioned surge tanks ( 29- A & 29- B ) absorb surge water from the main penstock during the high pressured compression and release water back to the main penstock during the low pressured expansion. Both are equipped with small one way valves on their tops to prevent the escape of air while allowing air to flow into the surge chambers; J. Motorized uni-direction spherical valves ( 5 ) connected to the end of the main penstock ( 4 ) ; K. A Pelton turbine-generator ( 7 ) similar to type I ;

L. A tail reservoir ( 10 ) inside the powerhouse; it receives exhaust water and it is drained to the main reservoir ( 22 ) via the drain pipe ( 30 ) by gravity flow;

M. Water supplemental pipes ( 31 -A & 31 -B ) to provide immediate water needed to stabilize the pressure in the main penstock. Water is sourced directly from main reservoir( 22 ).Both have check valves( 32-A & 32-B ) set below the main penstock to prevent backflow. It should be noted here, that the drawn in volume from the supplemental pipes into the main penstock is based on the difference of pressures on both sides of the check valves . On the main penstock side is the aggressive ups and downs of pressures as the system operates, while on the supplemental pipe side is the pressure originating from the elevation head from the main reservoir. The difference of pressures creates a suction force that transfer a certain volume of water into the main penstock. They are directly proportional. The bigger the difference in pressures, the bigger will be the suction force that could brought bigger volume of water. N. A replenishment pipe ( 16 ) similar to the type I , water is flowed into the main reservoir ( 22 ) as shown in Fig. 12.

THE FLOW PATH OF THE RE-CIRCULATING WATER IN TYPE I I CATEGORY SYSTEM

Fig. 13 shows water initially flows out from the main reservoir ( 22 ) into the entrance pipe ( 23 ) . It gets a high pressure head from the motor-pump ( 25 ). Then it flows into the convergence pipe ( 26 ), passes by the gate valves ( 27 ) and into the main penstocks ( 4 ). The main penstock has a length of 1,450 meters. The water would flow by the pressure relief valve ( 28 ) and the two air surge chambers ( 29-A & 29-B ) These surge chambers provide spaces to absorb surge water during compression phase in the main penstock and release water back to it during the expansion phase. Water then flow forward on the long main penstock, passing by two check valves ( 32-A & 32-B ) that control the entrance of supplemental water from the two water supplemental pipes ( 31 -A & 31 -B ). As the water journey to the end of the main penstock. It will meet the uni-direction spherical valve ( 5 ) in operations inside the powerhouse ( 9 ). These motorized spherical valves induce the water hammer pressures in the main penstocks and then releases the water jets possessing very high kinetic energy directly into the Pelton turbine-generator to generate electricity. The exhaust water now falls down into the tail reservoir ( 10 ) of the powerhouse ( 9 ). Water is now drained by gravitational force through the drain pipe ( 30 ) into the main reservoir ( 22 ), thereby COMPLETING THE WATER CIRCULATION LOOP.

Similar to the type I category system, the water supplemental pipes are connected to the main penstock nearer to the powerhouse ( 9 ). These pipes draw in water directly from the main reservoir ( 22 ) by the vacuum suction force as the downstream water in the main penstock is jetted out in a very huge volume. THIS COMPLETES THE CIRCULATION OF WATER IN A SHORTER SUB-LOOP — from the main reservoir to the supplemental pipes - main penstock - turbine - tail water reservoir and back to the main reservoir ( 22 ).

CALCULATED PERFORMANCE OF THE TYPE 11 CATEGORY SYSTEM

By using a 150 meter head pump, the energy equation of the flow inside the one meter ( inside diameter ) main penstock that ends in a 10 meter high orifice is:

150 = v2/ 2g + H TL + 10 the head lost is about 16.12 times the velocity head, thus:

150 = ( 1 + 16.12 ) v2/ 2g + 10 and v = 12.66 m/s This is the steady state flow rate and the discharge is 9.93 m3 / s.

The water hammer pressure when the spherical valve is " rapidly closed " in one second time is :

Ph = DmV Wp = ( 1000 )( 12.66 )( 1428 )

= 18,087 kpa In term of pressure head , it is 18,087 / g = 1 ,843 meters. This is nearly equal to the value of head we arrived at in the type I tower supported system which is 1 ,830 meters. ( see page 10 ) Similarly the steps in the computations of the type I I category system performance follow that computations of the type I category system in pages 10 to 13, a projected value of the average power of the released jet in type 1 1 category system is: Power = 127.46 ( 9810 ) ( 1342.8 )/ 1000 = 1 ,680 MW

Assuming an efficiency of 90 % for the turbine-generator, then the power produced is 1512 MW.

POWER OF THE PUMPS IN TYPE 11 CATEGORY SYSTEM The power required by one single pump ( 25 ) to give it a 150 meters head in steady state flow is :

Ppump = 9.93 ( 9810 ) ( 150 )/ 1000 = 14.6 MW

Assuming an efficiency of 90 % for the pump, then the power required is 16.23 MW.

Two pumps working simultaneously would require 32.46 MW. From the produced power of 1512 MW, we deduct the 32.46 MW for the two pumps and about 10 MW for the spherical valves and other equipments in the powerhouse, we would arrive at about 1 ,470 MW of transmittable electricity for the utility grid.

The net power of 1,470 MW produced by the type II system is higher than the 1 ,175 MW net power produced by type I system. Therefore it is more efficient.

The present invention is intended to be used as a base load generator. Whenever there is a decrease in the load demands, the excess capacity may be diverted to any other purposes within the powerhouse area , or we may opt to close partially the gate valves ( 27 ), so as to decrease the velocity head in the main penstock ( 4 ), thus a lower water hammer pressure, producing subsequently a lower level of power.

The present invention can be constructed as an independent power producing unit or it can be built as a sub-generation plant of an existing power plant. Thus the system serves as an energy multiplier. The above embodiments are given for illustration purposes only. And not by way of limitations and that modifications will become evident to those skilled in the arts which fall within the scope of the claims.

Claims

C L A I M S :
1. A hydro-electric system which features a controlled volume of water re- circulating continually within a closed loop of flow path : from an upper reservoir( 1 ) .water is initially flowed down fast into a 1 ,450 meters long main penstock that ends with a continuously rotating uni-direction spherical valve; this valve creates high water hammer pressure by rapid closing the fast moving water column in a one second time interval; subsequent rapid opening of the same valve transform the very high pressure energy into a very high kinetic energy water jet to impinge on the buckets of the Pelton turbine-generator to produce electrical power; the exhaust water fall into the tail reservoir inside the powerhouse; it is then flowed out to the cooling reservoir by gravity; from the cooling reservoir, water is drawn through an inflow pipe that is connected directly to the pump which has a motor that consume a much lesser power than the power produced by the Pelton turbine-generator, effecting a
SURPLUS OF POWER; the pump then delivers the water up back to the original upper reservoir ( 1 ) completing the loop; and the cycle continues, THIS BEING TYPE I CATEGORY.
2. A hydro-electric system which features a controlled volume of water re- circulating continually within a closed loop of flow path : from a ground level reservoir( 22 ), water is initially given a boost in pressure head by a main motor pump ( 25 ) to push forward into a 1 ,450 meter long main penstock, passing by pressure relief valve, surge chambers and water supplement pipes to the motorized uni-direction spherical valve; the continuously rotating spherical valve stops the fast water column in a " rapid closure " mode, transforming the kinetic energy in the entire water column into a water hammer of immense pressure energy; as the spherical valve opens, pressurized water is re- transformed into a very high kinetic energy jet that shoot out of the main penstock to impinge on the Pelton turbine-generator to generate electrical power that is of a much higher value than the power consumed by the main motor pump ( 25 ) mentioned effecting a SURPLUS OF POWER; the exhaust water then fall into the tail reservoir; from the tail reservoir, water is channeled by gravity through the outflow pipe back to the original main reservoir ( 22 ), completing the loop; and the cycle continues, THIS BEING TYPE II CATEGORY.
3. A hydro-electric system of claim 1 OR claim 2 that features a sub-loop of re-circulating water path : when the uni-direction spherical valve is opened, huge volume of water jets out of the main penstock into the atmosphere , creating a very high vacuum suction force that draw in water from the reservoirs ( 17 & 38 OR 22 ) directly into the main penstock through the water supplemental pipes, bypassing the rest of the main penstock to stabilize the pressure inside the main penstock; then on to the Pelton turbine and tail reservoir in the powerhouse and flows out by gravity back to the originating reservoirs ( 17 OR 22 ) completing the sub-loop; and the cycle continues.
4. A hydro-electric system of " claim 1 and claim 3 " OR " claim 2 and claim 3" which uses five forms of forces: a. The mechanical force of water jets released directly from the main penstock when the uni-direction spherical valve opens after undergoing a high pressured water hammer compression. b. The suction force created by the high vacuum after the huge expulsion of jet water from the main penstock that will draw in supplemental water directly from the reservoirs. c. The gravitational force induced elevation heads. d. The pressure head of the pump. e. The expanding inter-molecular space cohesion force of water molecules in the water column when the pressured water jet is released during expansion phase; the water column has been compressed into a smaller volume during the preceding high compression water hammer phase.
PCT/PH2005/000015 2005-07-26 2005-07-26 Re-circulating water in close-looped hydropower system WO2006085782A1 (en)

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ITRE20080116A1 (en) * 2008-12-16 2010-06-17 Giuseppe Mollo immersed Hydroelectric Power Station
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EP2071182A1 (en) 2007-12-14 2009-06-17 Jose Ching A multiple energy inputs hydropower system
AU2008203487B2 (en) * 2007-12-14 2011-06-09 Jose Ching A multiple energy inputs hydropower system
ITRE20080116A1 (en) * 2008-12-16 2010-06-17 Giuseppe Mollo immersed Hydroelectric Power Station
ITTV20090141A1 (en) * 2009-07-09 2011-01-10 Fabrizio Maria Spanu Plant for the production of energy by means of a conveying bath of a fluid in an impeller.
US9739268B2 (en) * 2009-12-21 2017-08-22 Ronald Kurt Christensen Transient liquid pressure power generation systems and associated devices and methods
US20150113968A1 (en) * 2009-12-21 2015-04-30 Ronald Kurt Christensen Transient liquid pressure power generation systems and associated devices and methods
US9915179B2 (en) 2009-12-21 2018-03-13 Ronald Kurt Christensen Transient liquid pressure power generation systems and associated devices and methods
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WO2013019656A3 (en) * 2011-07-29 2013-11-14 Saudi Arabian Oil Company System for producing energy using the water hammer effect
CN105190025A (en) * 2013-03-11 2015-12-23 O·E·M·罗德里格斯 Water gravity loop power plant (WGLPP)
WO2014164029A1 (en) * 2013-03-11 2014-10-09 Moncada Rodriguez Oscar Edgardo Water gravity loop power plant (wglpp)
WO2015088742A1 (en) * 2013-12-09 2015-06-18 Sims Joel D Electrical generator
GB2535120A (en) * 2013-12-09 2016-08-10 D Sims Joel Electrical generator
CN106062357A (en) * 2013-12-09 2016-10-26 乔尔·D·西姆斯 Electrical generator

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