KR20130039978A - Binary geothermal power generation system - Google Patents

Abstract

The present invention relates to a binary geothermal power generation system, in which cooling water supplied to a condenser of a power generation unit is cooled and circulated through a heat pump module to increase the temperature difference between the geothermal water caused by high temperature and the cooling water caused by low heat, The generation efficiency of power generation can be improved and the temperature of the cooling water can be appropriately adjusted in response to the change of the temperature of the geothermal water due to environmental factors and the like to stably maintain the operation state and power generation efficiency, The present invention provides a binary geothermal power generation system capable of preventing a change in temperature of cooling water caused by a factor, and maintaining a stable operation state.

Description

Binary Geothermal Power Generation System (Binary Geothermal Power Generation System)

The present invention relates to a binary geothermal power generation system. More specifically, the cooling water supplied to the condenser of the power generation unit is cooled and circulated through the heat pump module, thereby increasing the temperature difference between the high temperature heat water and the low temperature heat water, thereby improving the power generation efficiency of the geothermal power generation And even if the temperature of the geothermal water changes due to environmental factors or the like, the temperature of the cooling water can be appropriately adjusted correspondingly, so that the operation state and the power generation efficiency can be stably maintained, and the cooling water temperature change To a binary geothermal power generation system capable of maintaining a stable operation state.

The Earth in which we live has a distance from the surface to the center of nearly 6,500 km, and as it goes underground, the temperature gradually rises, reaching about 7,000 ° C in the center. The Earth has indeed infinite geothermal energy.

As global oil prices continue to rise and supply anxieties and response to climate change become urgent, promising solutions are near-infinite, sustainable renewable energy and geothermal energy that is present in each country's territory.

Geothermal energy is produced in the form of water vapor or geothermal water. The steam and geothermal water at high temperature (over 150 ℃) is mainly used for geothermal power generation, and the geothermal energy at medium and low temperature (below 150 ℃) depends on temperature. Binary geothermal power generation, hot spring, It is used for various purposes such as building heating.

Since 1904, the world's first geothermal power plant in Larderello, Italy, today, there are several forms of geothermal power generation in almost 20,000 countries, ranging from nearly 10,000 MW.

Conventional geothermal power generation methods are roughly divided into dry steam, geothermal power generation, flash steam, and binary geothermal power generation.

Dry Steam The geothermal power generation method is used when dry high pressure steam is produced. It is a method to turn Turbine directly to the produced steam.

Flash Steam The geothermal power generation method is used when high temperature geothermal fluid is produced. Spraying high temperature geothermal water with pressure into the low pressure tank causes flash (instantaneous evaporation), and the steam is used to turn the turbine.

Binary The geothermal power generation method is used when the temperature of geothermal water produced is not enough to use the above method or when environmental pollution should be avoided.

The binary geothermal power generation method is basically based on the organic Rankine Cycle and uses geothermal water as a heat source as a first medium and uses a water such as isopentane which evaporates at a much lower temperature than water 2 is used as the working fluid and the working fluid is evaporated by the heat of the geothermal water while passing through the evaporator which is the heat exchanger without direct contact between the geothermal water and the working fluid, . The working fluid in the vapor state passing through the turbine passes through a condenser, which is an air-cooled or water-cooled heat exchanger, and is condensed into a liquid state and sent back to the evaporator by the pump. That is, the working fluid circulates in the closed loop system, ie, the steam cycle, so that the geothermal water and the working fluid form a binary cycle. Due to this operation, it is possible to generate the geothermal water of medium and low temperature by using the binary power generation method, and the environmental pollution can be avoided.

Such binary geothermal power generation can be developed regardless of weather conditions and is operated in a closed circulation system, so there is no environmental pollution, low noise, most facilities are built in the basement, the ground facilities are small and very environmentally friendly, It is simple, easy to start and stop, can be developed in accordance with the time of high load, has a utilization rate of 95% or more in existing power plants, can be modularized into small and medium size, By expanding the development to distributed type by adding modules, it is possible to minimize the risk burden, maximize the economic efficiency, minimize the utilization rate loss due to maintenance, secure a high level of localization rate, It is also a sustainable clean renewable energy generation with many advantages such as reduction effect can be obtained.

However, such a geothermal power generation system is not widely utilized in terms of economy because the initial investment cost such as drilling-related technology and cost is too large. In the case of binary geothermal power generation, efforts have been made to improve the technology development by developing a low-grade rock layer, but the satisfactory technological development has not been achieved to date.

As described above, the binary geothermal power generation requires two energy sources, that is, a hot or heat source and a cold source or a heat sink. The conventional binary geothermal power generation method uses a geothermal water as a heat source to heat the evaporator And cooling the condenser by using air-cooling or water-cooling as a cold source. Basically, the heat-to-power efficiency is determined by the temperature difference between the heat source and the cold source.

Cooling towers are installed to circulate water by circulating water to draw water from nearby water sources such as rivers and ponds. Cooling temperature is low and cooling efficiency is much higher. However, Generally, air-cooling is widely used because there are no sources in the area where water is produced. In the case of air-cooled type, in summer, when the value of electricity increases, the cooling temperature rises due to rising atmospheric temperature, and the generation efficiency is greatly increased. In a hot region, the power generation amount is reduced to 40% or more. In the case of the water-cooled type, there is a problem that the cooling efficiency and the power generation efficiency are changed because the temperature of the cooling water changes due to seasonal factors.

In particular, in order to increase power generation efficiency, a temperature difference between two energy sources, that is, a heat source and a cool source, must be large. In the conventional structure through the air-cooling type or the water-cooling type, So that the temperature difference between the heat source and the cold source is not large, and accordingly, the power generation efficiency of the geothermal power generation system is lowered.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to increase the temperature difference between the geothermal water caused by the high temperature and the cooling water caused by the low heat by increasing the temperature of the cooling water supplied to the condenser of the power generation unit. To thereby provide a binary geothermal power generation system capable of improving the power generation efficiency of geothermal power generation.

Another object of the present invention is to cool the cooling water through one heat pump module and simultaneously heat the heating water so that the cooling device or the heating device need not be provided independently, The present invention provides a binary geothermal power generation system in which energy efficiency is improved because no waste heat is generated during operation of the heat pump module.

It is a further object of the present invention to enable the temperature of the cooling water to be changed by adjusting the operation state of the heat pump module so that the temperature of the cooling water can be appropriately adjusted in response to the change of the temperature of the geothermal water due to environmental factors Thereby enabling a stable operation state and power generation efficiency to be maintained.

It is still another object of the present invention to provide a binary geothermal power generation system capable of maintaining a stable operation state by preventing a change in the temperature of cooling water due to environmental factors by providing a separate cooling water capable of adjusting the cooling temperature together with cooling water by a cooling tower .

It is a further object of the present invention to provide a method of controlling the temperature of a geothermal water by selectively controlling the flow of heated water according to the geothermal water temperature in a state of exchanging heat with the power generation unit, And to provide a geothermal power generation system.

The present invention relates to a geothermal water circulation unit for extracting and circulating geothermal water in a basement; A power generating unit that circulates the steam cycle of the pump, the evaporator, the turbine, and the condenser, the working fluid being supplied with heat from the geothermal water through the evaporator and rotating the turbine; And a heating water heating unit that receives heat from the working fluid through the condenser and heats and supplies the heating water. The heating water heating unit includes a heating water tank for storing heating water, and a heating water tank for heating the first cooling water to the condenser A cooling water tank circulatingly supplied with the cooling water to store the first cooling water for heat exchange with the working fluid of the condenser; a cooling water tank for heating the heating water of the heating water tank and cooling the first cooling water of the cooling water tank; And a heat pump module operating as a high-temperature source and a low-temperature source, respectively.

At this time, the binary geothermal power generation system may further include a cooling tower for circulating the second cooling water to the condenser and storing the second cooling water to heat-exchange the working fluid of the condenser.

The second cooling water pipe circulating and supplying the second cooling water from the cooling tower to the condenser may be connected to the first cooling water pipe circulating and supplying the first cooling water from the cooling water tank to the condenser.

The first cooling water pipe and the second cooling water pipe may be connected to each other by a three-way valve, and the first and second cooling water flow rates may be adjusted by the three-way valve.

Meanwhile, the geothermal water circulation unit is further provided with a separate heat exchanger for heat exchange of geothermal heat that has undergone heat exchange through the evaporator, and the heating water supply pipe connected to the heating water tank is supplied and discharged from the heating water tank The heating water can be formed so as to be heat-exchanged with the geothermal water via the heat exchanger, and then supplied and discharged.

At this time, the heating water supply pipe may be equipped with a three-way valve capable of adjusting the path so that the heating water passes through the heat exchanger according to the temperature of the geothermal water, and then supplied or discharged to the heating water tank.

According to the present invention, the cooling water supplied to the condenser of the power generation unit is cooled and circulated through the separate heat pump module, thereby increasing the temperature difference between the high temperature heat water and the low heat water cooling water, Can be improved.

In addition, since the cooling water is cooled and the heating water is heated through one heat pump module, a separate cooling device or a heating device is not required to be independently provided, thereby simplifying the structure of the device, Since the waste heat is not generated during operation, energy efficiency is also improved.

Further, by allowing the temperature of the cooling water to be changed by adjusting the operation state of the heat pump module, even if the temperature of the geothermal water changes due to environmental factors or the like, the temperature of the cooling water can be appropriately adjusted corresponding thereto, And the power generation efficiency can be stably maintained.

Further, it is possible to supply a separate cooling water capable of adjusting the cooling temperature together with the cooling water by the cooling tower, thereby preventing a change in the temperature of the cooling water due to environmental factors and maintaining a stable operation state.

Further, by selectively regulating the flow of the heating water in accordance with the geothermal water temperature in the heat-exchanged state with the power generation unit, the heating water or the geothermal water is heated and supplied again, thereby further improving the thermal efficiency.

FIG. 1 is a block diagram conceptually showing the overall configuration of a binary geothermal power generation system according to an embodiment of the present invention. FIG.
2 is a block diagram conceptually showing a basic configuration of a heating water heating unit according to an embodiment of the present invention;
3 is a block diagram conceptually showing a configuration in which a cooling tower is included in a heating water heating unit according to an embodiment of the present invention.
4 is a block diagram conceptually illustrating a heating water flow of a heating water tank according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a block diagram conceptually showing an overall configuration of a binary geothermal power generation system according to an embodiment of the present invention. FIG. 2 conceptually shows a basic configuration of a heating water heating unit according to an embodiment of the present invention Block diagram.

The binary geothermal power generation system according to an embodiment of the present invention is a geothermal power generation system in which geothermal water and a working fluid are circulated and exchanged in different cycles, respectively, and includes a geothermal water circulation unit 100, a power generation unit 200, , And a heating water heating unit (300).

The geothermal water circulation unit 100 is configured to extract geothermal water at a high temperature from the ground and heat-exchange the geothermal water with the working fluid through the evaporator 220 of the power generation unit 200, The number of geothermal water used is about 100 ° C to 120 ° C. The geothermal water circulation unit 100 is configured to extract geothermal water by using a separate geothermal water pump (not shown) and to flow through the geothermal water pipe line 101, Is configured to pass through the evaporator (220) of the power generation unit (200) and exchange heat with the working fluid. The configuration of the geothermal water circulation unit 100 can be configured in various general methods used in a binary geothermal power generation system.

The power generation unit 200 forms a steam cycle consisting of a pump 210, an evaporator 220, a turbine 230, and a condenser 240, and the working fluid circulates through the steam cycle and flows through the evaporator 220, To rotate the turbine (230). At this time, the pump 210, the evaporator 220, the turbine 230, and the condenser 240 are connected by the steam cycle piping line 201 so as to circulate the working fluid.

In more detail, the working fluid in the power generation unit 200 is compressed by the pump 210, exchanges heat with the geothermal water in the geothermal water circulation unit 100 in the evaporator 220, And expands. In this process, the turbine 230 is rotated to generate power generation energy. The working fluid that has passed through the turbine 230 is circulated in such a manner that the working fluid in the condenser 240 is heat-exchanged with the cooling water and is condensed and then introduced into the pump 210 and compressed.

That is, the working fluid receives thermal energy from the geothermal water in the evaporator 220, rotates the turbine 230 to generate power generation energy, and again discharges thermal energy through the cooling water in the condenser 240. The power generation efficiency of the power generation unit 200 constituting the power generation unit 200 is proportional to the temperature difference between the geothermal water caused by the high temperature and the cooling water caused by the low temperature.

The binary geothermal power generation system according to the embodiment of the present invention is configured to decrease the temperature of the cooling water through the heating water heating unit 300 so as to increase the temperature difference between the geothermal water and the cooling water to improve the power generation efficiency The heating water heating unit 300 is configured to supply heat from the working fluid through the condenser 240 of the power generation unit 200 and to supply the heating water P.

1 and 2, the heating water heating unit 300 includes a heating water tank 310 for storing heating water P, a cooling water tank 320 for storing the first cooling water Q1, The heating water P and the first cooling water Q1 are heated to a high temperature and a low temperature to cool the heating water P of the heating water tank 310 and cool the first cooling water Q1 of the cooling water tank 320, And a heat pump module 330 operating as a circle.

The cooling water tank 320 stores the first cooling water Q1 and circulates the first cooling water Q1 through the first cooling water pipe 321 to the condenser 240 of the power generation unit 200 And a separate supply pump 370 is installed in the first cooling water pipe 321 so that the first cooling water Q1 is circulated and supplied. Accordingly, the working fluid of the power generation unit 200 is condensed by discharging heat to the first cooling water Q1 in the condenser 240, and the first cooling water Q1 absorbs the heat of condensation from the working fluid, 320, respectively. On the other hand, water is supplied to the heating water tank 310 from another water supply facility 400 and stored as heating water P, and then supplied to each household or factory through the heating water supply pipe 311 as heating water .

At this time, the cooling water tank 320 and the heating water tank 310 are cooled and heated by the heat pump module 330, respectively. That is, the heat pump module 330 constitutes a refrigeration cycle composed of the compressor 331, the condenser 334, the expansion valve 333, and the evaporator 332, and the refrigerant is configured to circulate the refrigeration cycle. At this time, the evaporator 332 is located inside the cooling water tank 320 to cool the first cooling water Q1 through heat exchange with the refrigerant, and the condenser 334 is located inside the heating water tank 310 to exchange with the refrigerant. Heating water P is heated by heat exchange.

According to this structure, the first cooling water Q1 is cooled through the single heat pump module 330 and the heating water P is heated while the cooling device or the heating device is not independently provided. Therefore, The energy efficiency is also improved because the heat pump module 330 does not generate waste heat.

As described above, the power generation efficiency of the power generation unit 200 is proportional to the difference between the temperature of the geothermal heat caused by the high temperature and the temperature of the cooling water caused by the low temperature. In the binary geothermal power generation system according to the embodiment of the present invention, Since the first cooling water (Q1) supplied to the condenser (240) is supplied in a cooled state by the heat pump module (330), the temperature of the cooling water becomes lower than in the prior art. Therefore, the temperature difference between the high heat source and the low heat source further increases, so that the power generation efficiency is improved.

Meanwhile, since the temperature of the first cooling water Q1 stored in the cooling water tank 320 can be changed by changing the cooling performance of the heat pump module 330 by controlling the operation state of the heat pump module 330, The temperature of the cooling water can be appropriately adjusted according to the user's need. For example, the temperature of the geothermal water extracted by the geothermal water circulation unit 100 is not always kept constant, but changes by a certain degree due to environmental factors. When the temperature of the geothermal water changes, The operation state of the power generation unit 200 is changed, so that the operation of the power generation unit 200 becomes unstable or the power generation efficiency changes. In this case, the binary geothermal power generation system according to an embodiment of the present invention can adjust the temperature of the first cooling water Q1 to correspond to the geothermal water temperature change by adjusting the operation state of the heat pump module 330, The operating state of the power generation unit 200 and the power generation efficiency can be more stably maintained.

3 is a block diagram conceptually showing a structure in which a cooling tower is included in a heating water heating unit according to an embodiment of the present invention.

1 and 3, the heating water heating unit 300 according to an embodiment of the present invention includes a cooling tower 340 for circulating and supplying the second cooling water Q2 to the condenser 240 of the power generation unit 200 ) May be further provided.

Water is supplied to the cooling tower 340 from a separate water supply facility 400 and is cooled and stored in the second cooling water Q2 through ventilation with outdoor air. The second cooling water Q2 thus cooled and circulated to the condenser 240 of the power generation unit 200 through the second cooling water pipe 341 is supplied to the condenser 240 through the heat exchange .

At this time, the second cooling water pipe 341 may be connected to the first cooling water pipe 321 so that the first cooling water Q1 and the second cooling water Q2 are mixed with each other, And then supplied to the condenser 240.

In addition, the first cooling water pipe 321 and the second cooling water pipe 341 are configured to be connected to each other by a three-way valve 350 capable of adjusting the flow rate, the power generation unit 200 through the three-way valve 350 The flow rates of the first cooling water Q1 and the second cooling water Q2 supplied to the condenser 240 may be adjusted.

In this case, the flow rate of the first cooling water Q1 is adjusted to be higher. In contrast, when the outside temperature is relatively high as in the winter season, If the external temperature is relatively low, the cooling efficiency of the cooling tower 340 is increased. In this case, the flow rate of the first cooling water Q1 can be adjusted to be further lowered. With this adjustment, the temperature of the cooling water supplied to the condenser 240 of the power generation unit 200 can be kept constant, and thus the operating state and the power generation efficiency of the power generation unit 200 can be stably maintained.

4 is a block diagram conceptually illustrating a heating water flow of a heating water tank according to an embodiment of the present invention.

In the geothermal water circulation unit 100 according to an embodiment of the present invention, as shown in FIGS. 1 and 4, a separate heat exchanger 110 may exchange heat again through the heat exchange process through the evaporator 220. May be further provided.

In this case, in the heating water supply pipe 311 connected to the heating water tank 310, the heating water P supplied and discharged from the heating water tank 310 is geothermally passed through the heat exchanger 110 of the geothermal water circulation unit 100. It is formed to be discharged after the heat exchange with the water, the heating water supply pipe 311 is equipped with a separate supply pump 370 for the flow of the heating water (P).

According to this structure, the heating water P heated by the heat pump module 330 is once again heat-exchanged with the geothermal water in the course of supplying and discharging, and can be supplied to a supply source such as a home or a factory in a heated state again.

In this case, the heating water supply pipe 311 may be equipped with a separate three-way valve 360, as shown in Figure 4, the heating passed through the heat exchanger 110 by the three-way valve 360. The water P is preferably configured to be selectively routed in such a manner that the water P is supplied to or discharged from each supply source or flows back into the heating water tank 310, and the path control is configured to be selectively applied according to the temperature of the geothermal water. Can be.

That is, although not shown, the geothermal water pipe line 101 is equipped with a temperature sensor (not shown) capable of measuring the geothermal water temperature after passing through the evaporator 220 of the power generation unit 200, such a temperature sensor When the temperature of the geothermal water measured by the temperature is higher than the temperature of the heating water P supplied and discharged from the heating water tank 310, the heat exchange of the geothermal water circulation unit 100 as shown in Fig. 4 (a) The flow of the heating water passing through the machine 110 is adjusted to supply and discharge to each source by the three-way valve 360. On the other hand, when the temperature of the geothermal water measured by the temperature sensor is lower than the temperature of the heating water P supplied and discharged from the heating water tank 310, as shown in (b) of FIG. 4, the geothermal water circulation unit ( The flow of the heating water passing through the heat exchanger 110 of the 100 is adjusted to be introduced into the heating water tank 310 by the three-way valve 360. At this time, the geothermal water is circulated in a state of being heated to a certain extent through heat exchange with the heating water P.

According to this structure, the binary geothermal power generation system according to an embodiment of the present invention can heat and heat the heating water P once more through heat exchange with the geothermal water according to the temperature of the geothermal water, The geothermal water can be circulated by heating the geothermal water to a certain degree by recirculating the geothermal water to the heating water tank 310. Therefore, it is possible to stably operate in more various ways as required, thereby further improving the power generation efficiency.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

100: Geothermal water circulation unit 110: Heat exchanger
200: power generation unit 210: pump
220: Evaporator 230: Turbine
240: condenser 300: heating water heating unit
310: Heating water tank 320: Cooling water tank
330: Heat pump module 340: Cooling tower
350, 360: Three way valve

Claims (6)

Geothermal water circulation unit for extracting and circulating geothermal water from the basement;
A power generation unit circulating a steam cycle of a pump, an evaporator, a turbine, and a condenser, and operating to rotate the turbine by receiving heat from the geothermal water through the evaporator; And
Heating water heating unit for receiving heat from the working fluid through the condenser to heat the heating water
To include, the heating water heating unit
A heating water tank storing heating water, a cooling water tank circulating and supplying first cooling water to the condenser, and storing the first cooling water to exchange heat with a working fluid of the condenser, and heating the heating water of the heating water tank and And a heat pump module configured to operate the heating water and the first cooling water as a high heat source and a low heat source, respectively, to cool the first cooling water of the cooling water tank.
The method of claim 1,
And a cooling tower configured to store the second cooling water to circulate the second cooling water to the condenser and to exchange heat with the working fluid of the condenser.
3. The method of claim 2,
And a second cooling water pipe configured to circulate and supply the second cooling water from the cooling tower to the condenser, wherein the second cooling water pipe is formed to be connected to the first cooling water pipe that circulates and supplies the first cooling water from the cooling water tank to the condenser.
The method of claim 3, wherein
And the first cooling water pipe and the second cooling water pipe are connected to each other by a three-way valve, and the first and second cooling water flow rates are controlled by the three-way valve.
The method according to any one of claims 1 to 4,
The geothermal water circulation unit is further provided with a separate heat exchanger to heat-exchange the geothermal water undergoing a heat exchange process through the evaporator,
Binary geothermal power generation system characterized in that the heating water supply pipe connected to the heating water tank is formed so that the heating water discharged from the heating water tank is discharged after the heat exchange with the geothermal water through the heat exchanger.
The method of claim 5, wherein
Binary geothermal heat characterized in that the heating water supply pipe is equipped with a three-way valve for controlling the route so that the heating water is supplied or discharged after passing through the heat exchanger or flows back into the heating water tank according to the temperature of the geothermal water Power generation system.

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