US20120079826A1

US20120079826A1 - Water circulation power generation system for energy recovery

Info

Publication number: US20120079826A1
Application number: US12/897,803
Authority: US
Inventors: Tzu-Kwang LEE
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-05
Filing date: 2010-10-05
Publication date: 2012-04-05

Abstract

A water circulation power generation system for energy recovery includes at least one water circulation power generation system connected to a heat exchange system to obtain required water for a heat exchange process. The water circulation power generation system includes a water tank to store cooling water, a water supply pipeline and a recovery pipeline. The water supply pipeline draws water from the water tank to supply front end water to the heat exchange system. The recovery pipeline guides operational circulation water discharged from the heat exchange system and has a hydraulic power generator installed thereon driven by the operational circulation water to convert kinetic energy thereof to electric power. Thus during the operational circulation water flows to its recovery destination, its kinetic energy drives the hydraulic power generator to produce additional electric power.

Description

FIELD OF THE INVENTION

The present invention relates to a water circulation power generation system for energy recovery and particularly to a power generation system to recover kinetic energy of tail water of water circulation piping.

BACKGROUND OF THE INVENTION

With constant increasing of world population and widely use of electronic devices and development of transportation, global energy resources become extremely shortened. Many countries and institutions have devoted huge amount of investments in developing alternative energy. At present, alternative energy is still constrained by production intensity and cannot fully meet requirements of consumers' habits. To substitute existing energy resources by extensive alternative energy still is far to reach.
However, there is still a lot of energy in people's life that can be recovered and reused. For instance, water circulation piping is installed in general buildings, the so-called process water or air conditioner cooling water, they all pass through a recovery pipeline in the water circulation piping. Water is cleaned in the recovery pipeline and flowed back to the water circulation piping through the kinetic energy generated by elevation difference.
Take a commercial building as an example. The commercial building equipped with an air conditioning system or a cooling system generally has a heat exchange device at a higher floor (usually at the top floor), which is incorporated with a cooling water tower to draw water as the medium for heat exchange. The water discharged from the heat exchange device can be flowed back repeatedly to the heat exchange device and cooling water tower for cooling purpose.
Another example is a power generation plant (such as a nuclear power plant) that requires huge amount of cooling water that often is drawn from seawater. The cooling water also goes through a heat exchange process with used water (commonly called “tail water”) discharged to the sea by elevation difference (or with aid of pumps).
In the aforesaid conventional water circulation piping, mostly the tail water in the recovery pipeline at the last section thereof can automatically flow by elevation difference. The tail water has kinetic energy which is generated by automatic flowing and is not fully used in the existing techniques. It is a waste of energy. There is still room for improvement especially in the age of increasing shortage of energy resources we are facing today.

SUMMARY OF THE INVENTION

In view of increasing shortage of global energy resources and governments and private institutions worldwide having devoted a great deal of investments in developing eco-friendly new energy resources or trying to enhance equipment efficiency to provide sustainable benefit for people now living and future generations, and with the urgent energy requirement at present, to wait for new technology or another five or ten years for building new power generation plants to fill in the existing energy vacancy would be unrealistic. Hence the present invention aims to provide an energy recovery structure to utilize the kinetic energy generated by cooling water that is existed in the central air conditioning of general commercial buildings or fire power generation plants constantly circulating back to its container to recover the unused energy without affecting the original circulation route. Thus the invention not only can generate power also can minimize the load of the power plants and reduce emission of carbon dioxide.
The present invention provides a water circulation power generation system for energy recovery including at least one water circulation power generation system connected to a heat exchange system to obtain required water for heat exchange process. The water circulation power generation system includes a water tank to store cooling water, a water supply pipeline and a recovery pipeline. The water supply pipeline draws water from the water tank and supplies front end water to the heat exchange system. The recovery pipeline guides operational circulation water discharged from the heat exchange system, and has a hydraulic power generator installed thereon driven by the operational circulation water to convert kinetic energy of the operational circulation water to electric power.
Thus during the operational circulation water flows to a recovery destination, its kinetic energy can drive the hydraulic power generator to generate additional electric power. It can save a lot of power consumption in a long-term use, and also achieve long-term goals of energy saving and carbon reduction and ecological development maintenance now pursued by governments worldwide.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the invention adapted to a conventional cooling water tower.

FIG. 2 is a schematic view of an embodiment of the invention adapted to a cooling water tower of a commercial building.

FIG. 3 is a schematic view of the invention adapted to a refrigeration set of a conventional industrial and general building.

FIG. 4 is a schematic view of an embodiment of the invention adapted to a cooling water tower of a nuclear power plant.

FIG. 5 is a schematic view of an embodiment of the invention adapted to a nuclear power plant with the cooling water discharged directly

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention aims to provide a water circulation power generation system for energy recovery including at least one water circulation power generation system connected to a heat exchange system to obtain water needed for heat exchange process. Referring to FIG. 1, the water circulation power generation system includes a water tank 1 to store cooling water, a water supply pipeline 2 and a recovery pipeline 4. The heat exchange system 3 is connected to the water supply pipeline 2 and recovery pipeline 4. The water supply pipeline 2 includes at least one water drawing pump 21, a water stop valve 22 and a check valve 23. The water drawing pump 21 draws water from the water tank 1 and supplies front end water to the heat exchange system 3. The check valve 23 prevents the water from flowing back to the water tank 1. The water stop valve 22 closes the water supply pipeline 2 during repairing or replacing the pipeline. The front end water supplied to the heat exchange system 3 serves as a medium for heat exchange. The heat exchange system 3 can be implemented in many types. FIG. 1 illustrates one of the possible types that includes a set of radiation fins 31, a cooling water tower 32 and a fan 33. The radiation fins 31 are directly in contact with the front end water to exchange heat. The water passed through the radiation fins 31 flows to the cooling water tower 32 which has the fan 33 installed on the surrounding thereof. The fan 33 generates airflow to carry the heat away. The water discharged from the cooling water tower 32 is defined as operational circulation water after finishing the heat exchange process of the heat exchange system 3. The recovery pipeline 4 guides the operational circulation water discharged from the heat exchange system 3, and has a hydraulic power generator 41 installed thereon driven by the operational circulation water and another water stop valve 42. The hydraulic power generator 41 is driven by the operational circulation water to convert kinetic energy of the operational circulation water to electric power. The operational circulation water guided by the recovery pipeline 4 can be guided back again to the water tank 1 to be reused for the heat exchange system 3. The water circulation power generation system further includes a branched backup pipeline 5 communicating with the recovery pipeline 4. The backup pipeline 5 also has a water stop valve 51. As the recovery pipeline 4 and hydraulic power generator 41 require periodical repair and maintenance, the recovery pipeline 4 and backup pipeline 5 can be alternately used when necessary. In regular conditions, the water stop valve 42 of the recovery pipeline 4 is opened to let the operational circulation water to pass through the hydraulic power generator 41, while the water stop valve 51 of the backup pipeline 5 is closed. During repair and maintenance of the hydraulic power generator 41, the water stop valve 42 is closed and another water stop valve 51 is opened to let the operational circulation water to pass through the backup pipeline 5. By means of the technique set forth above, the kinetic energy of the operational circulation water can drive the hydraulic power generator 41 to generate electric power to produce additional power. After long-term use, a lot of extra electric power can be produced, and long-term goals of extra energy production and carbon reduction and ecological development maintenance now pursued by governments worldwide can also be achieved.
Referring to FIG. 2, the water circulation power generation system previously discussed can be installed in an air conditioning system of a building. Take a building with twenty floors on the ground and three floors underground as an example. Assumed the building has a chill water machine set (heat exchange system 3) with a capacity of 750 tons serving as the central air conditioning system. If a water tank is located in a machine room at the third floor underground, and each floor has an average height of three meters.
The height from the underground water tank to the top floor is: 23×3 m=69 m
The water required by the cooling water tower of the chill water machine set is: 750 t×0.0002 m³/s=0.15 m³/s (1 ton requires about 0.0002 m³/s of water).
The capacity of the water drawing pump 2 supplying water to the cooling water tower is:
0.15 m³/s×69 m×9.81×1000 kg/m³/0.8=127 KW
The estimated recovery energy of the hydraulic power generator 41 is:
0.15 m³/s×69 m×9.81×1000 kg/m³×0.8=81 KW
Assumed the chill water machine set consumes average NT $3/KWh in operating 24 hours every day, the energy recovery saved everyday is:
81 KW×24 hours×NT$3/KWh=NT$5832 (about USD$180)
Please refer to FIG. 3. It includes a refrigeration set 312 which contains a condenser 310 and an evaporator 311. The evaporator 311 obtains water from a chill water tank 1 a through a chill water drawing pump 21 a. The condenser 310 obtains water from a cooling water tank 1 b through a cooling water drawing pump 21 b. The water circulation power generation system is connected to a rear end of the condenser 310 or evaporator 311, or the condenser 310 and evaporator 311 are connected respectively to a water circulation power generation system as shown in FIG. 3. The evaporator 311 guides the operational circulation water back to the chill water tank 1 a through the recovery pipeline 4. The chill water tank 1 a can include a chill water supply pump 6 supplying chill water to plant facilities or air conditioning equipment of the building. The water discharged from the condenser 310 first flows to the cooling water tower 32 to be cooled by the fan 33, then the operational circulation water is guided back to the cooling water tank 1 b through another recovery pipeline 4. Both of the recovery pipelines 4 have hydraulic power generators 41 installed thereon to improve utilization of the kinetic energy of the operational circulation water.
Referring to FIG. 4, the heat exchange system 3 and water circulation power generation system can be installed in a power plant, and a nuclear power plant is taken as an example in this embodiment. Water in the water tank 1 is supplied to the heat exchange system 3 through the water drawing pump 21 and the water supply pipeline 2. In an embodiment shown in FIG. 4, the heat exchange system 3 includes a condenser 34 and a cooling water tower 35. The condenser 34 contains condensed water which is sent to a nuclear reactor 7 through a condensed water pump 341. The condensed water is evaporated into steam in the nuclear reactor 7 to drive a steam turbine 71 and a power generator 72 to generate electric power. The electric power is distributed through a power distribution station 73. The steam passing through the steam turbine 71 returns to the condenser 34 to be condensed into water again. The front end water provided by the water supply pipeline 2 is used to exchange heat in the condenser 34. The water passes through the condenser 34 and is cooled in the cooling water tower 35, then the water is sent back to the water tank 1. The hydraulic power generator 41 is located on the recovery pipeline 4 between the cooling water tower 35 and water tank 1 to recover the kinetic energy of the operational circulation water.
Refer to FIG. 5 for another embodiment with a nuclear power plant as an example. The operational circulation water passing through the condenser 34 may also be directly discharged to the sea through the recovery pipeline 4 as shown in FIG. 5, and the kinetic energy of the operational circulation water is recovered by the hydraulic power generator 41 before discharging to the sea.
Take Chinshan nuclear power plant in Taiwan as an example. It has two steam turbine generators, each has a capacity of 636 Mw thus total is 1272 Mw. Assumed that the discharge temperature difference is set at 10° C., the cooling water amount required for each steam turbine generator is:
GMP=14295×636 Mw/18 F (10° C.)=505090 gpm=31.9 m³/sec
If the water pressure at the distal end of the pipeline is 1 kg/cm², and the height of the water head is about 10 m, the estimated recovery energy is:
Water amount×water head height×9.81×efficiency×density=31.9 m³/sec×10 m×9.81 m/s/s×0.8×1000 kg/m³=2503 KW
Assumed that operating 24 hours a day with average consumption of NT$3/KWh, the energy recovery saved everyday is: 2503 KW×24 hours×3=NT$180216 (about USD $5600)
The above estimate shows merely the direct energy recovery yield, additional potential yield of carbon discharge (carbon dioxide trade) is saved:
The coal-fired power generation has carbon discharge of 2.095 lbs/KWh, oil-fueled power generation has carbon discharge of 1.969 lbs/KWh, and gas/natural gas-fueled power generation has carbon discharge of 1.321 lbs/KWh. Thus the average of the three above mentioned power generation ways has carbon discharge of 1.795 lbs/KWh.
Thus the carbon discharge converted from the alternate power plant carbon emission is: 1.795×2503 KWh/2200 lbs=2.04 tons
Assumed that the exchange price of carbon dioxide is NT$ 331/ton, the additional yield is NT$16206 (about USD$500) per day.
While FIGS. 4 and 5 illustrate an embodiment with a nuclear power plant, the technique proposed by the invention can also be adapted to a thermal power plant by capturing the operational circulation water in the water circulation power generation system to generate electric power. Various operation types of the power plants also can be included in the invention.
In short, the present invention can save or recover a great deal of power in the long run, and achieve long-term goals of energy recovery and carbon reduction and ecological development maintenance now pursued by governments worldwide.
While the invention has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
In summation of the above description, the present invention provides a significant improvement over the conventional techniques and complies with the patent application requirements, and is submitted for review and granting of the commensurate patent rights.

Claims

1. A water circulation power generation system for energy recovery including at least one water circulation power generation system connected to a heat exchange system to obtain water required for a heat exchange process, the water circulation power generation system comprising:

a water tank to store cooling water;

a water supply pipeline which draws water from the water tank and supplies front end water to the heat exchange system; and

a recovery pipeline which guides operational circulation water discharged from the heat exchange system and includes a hydraulic power generator driven by the operational circulation water to convert kinetic energy thereof to electric power.

2. The water circulation power generation system of claim 1, wherein the water supply pipeline includes at least one water drawing pump, a water stop valve and a check valve.

3. The water circulation power generation system of claim 1 further including a branched backup pipeline communicating with the recovery pipeline.

4. The water circulation power generation system of claim 3, wherein the recovery pipeline and the backup pipeline include respectively a water stop valve.

5. The water circulation power generation system of claim 1, wherein the heat exchange system includes a condenser and an evaporator, the water circulation power generation system being connected to the condenser or the evaporator.

6. The water circulation power generation system of claim 1, wherein the heat exchange system includes a condenser and an evaporator that are connected respectively to one water circulation power generation system.

7. The water circulation power generation system of claim 1, wherein the heat exchange system is located in an air conditioning system of a building.

8. The water circulation power generation system of claim 1, wherein the heat exchange system is located in a power plant.