JP2012017703A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generation system that further increases power generation efficiency, by reducing heating loss and waste heat.SOLUTION: A first compressor 21 of a circulating part 11 compresses a first working fluid, a heat source 22 heats the first working fluid, and a turbine 23 can be driven by the first working fluid. An expander 24 of a heat pump 12 expands a second working fluid, a second compressor 25 compresses the second working fluid, and a heat radiating part 26 diffuses heat of the second working fluid. A low-temperature side heat exchanger 13 exchanges heat among the first working fluid flowing to the first compressor 21 from the turbine 23, the second working fluid flowing to the expander 24 from the heat radiating part 26 and the second working fluid flowing to the second compressor 25 from the expander 24. A high-temperature side heat exchanger 14 exchanges heat between the first working fluid on the upstream side of the low temperature side heat exchanger 13 flowing to the first compressor 21 from the turbine 23 and the first working fluid flowing to the heat source 22 from the first compressor 21. A generator 15 generates electric power by driving the turbine 23.

Description

  The present invention relates to a power generation system.

  As a power generation system using a conventional heat engine, a stage in which the working fluid is compressed to increase its temperature, a stage in which heat is exchanged between the working fluid and the heat source, the working fluid is superheated, and a superheated working fluid And expanding the pressure to drive the turbine, thereby reducing the temperature, condensing the working fluid to further reduce its temperature, and returning the working fluid to the compression stage, and exchanging heat with the compression stage There is one in which the working fluid passing between the stages exchanges heat with the working fluid passing between the expansion stage and the condensation stage to regenerate the heat of the working fluid (for example, see Patent Document 1). In addition, there is an apparatus that increases the amount of power generation by recovering the waste heat of exhaust steam discharged from the steam turbine by an absorption heat pump and raising the temperature of the condensate (see, for example, Patent Document 2).

Special table 2009-537774 JP-A-8-21209

  Although the conventional power generation systems as described in Patent Documents 1 and 2 are configured to increase power generation efficiency, there is still a problem that heat generation loss and waste heat are still large. For this reason, a more efficient power generation system is desired.

  The present invention has been made paying attention to such a problem, and an object of the present invention is to provide a power generation system capable of reducing heat generation loss and waste heat and further improving power generation efficiency.

  In order to achieve the above object, a power generation system according to the present invention includes a circulation unit, a heat pump, a low temperature side heat exchanger, a high temperature side heat exchanger, and a generator, and the circulation unit includes a first compressor and a heat source. A first working fluid that circulates between the first compressor and the turbine, the first compressor being provided to compress the first working fluid, and the heat source being The first working fluid compressed by the first compressor is provided to be heated, the turbine is provided to be drivable by the first working fluid heated by the heat source, and the heat pump includes an expander and a second A compressor and a heat dissipating unit, and a second working fluid that circulates between the expander and the second compressor, the expander being provided to expand the second working fluid, The second compressor is the second working flow expanded by the expander. The heat radiating portion is provided to dissipate heat of the second working fluid compressed by the second compressor, and the low temperature side heat exchanger is connected to the first compressor from the turbine. Heat exchange is performed between the first working fluid heading toward the second working fluid and the second working fluid heading toward the expander from the heat dissipating unit, and the second working fluid heading toward the second compressor from the expander, The high temperature side heat exchanger is provided to heat the second working fluid from the expander toward the second compressor, and the high temperature side heat exchanger is upstream of the low temperature side heat exchanger from the turbine toward the first compressor. Heat exchange is performed between the first working fluid and the first working fluid heading from the first compressor toward the heat source, and the first working fluid heading from the first compressor toward the heat source is heated. And the generator is That is provided to be generated by driving the turbine, characterized.

  The power generation system according to the present invention can generate electric power by driving a generator with a turbine as follows. First, in the circulation section, the first working fluid compressed by the first compressor is heated by heat exchange in the high temperature side heat exchanger, and further to a temperature at which the turbine can be driven by the heat source, for example, about 500 to 1000 ° C. Heated. The turbine is driven by the heated first working fluid, thereby generating power by driving the generator. The first working fluid that has driven the turbine is deprived of heat by heat exchange in the high-temperature side heat exchanger and further deprived of heat by heat exchange in the low-temperature side heat exchanger. The first working fluid whose temperature has decreased is compressed again by the first compressor and travels to the turbine.

  Next, in the heat pump, the second working fluid expanded by the expander is heated by heat exchange in the low temperature side heat exchanger, and further compressed by the second compressor. The compressed second working fluid dissipates heat at the heat dissipating part to lower the temperature, and further, heat is taken away by heat exchange at the low-temperature side heat exchanger to lower the temperature. The second working fluid whose temperature has decreased is expanded again by the expander and travels to the second compressor. Thus, the power generation system according to the present invention can increase power generation efficiency by using the heat pump, the high temperature side heat exchanger, and the low temperature side heat exchanger.

  The power generation system according to the present invention can increase the thermal efficiency by operating the heat pump near room temperature, and efficiently use the heat released from the heat radiating unit for heating, hot water supply, temperature rise of the first working fluid, and the like. Can do. The compression efficiency can be increased by lowering the compression ratio of the second compressor of the heat pump and suppressing the temperature rise. In addition, the loss due to heat generation can be reduced by compressing from the low temperature with the first compressor in the circulation section. Since the first working fluid having a high pressure can be obtained by using the second working fluid having a low compression ratio, it can be brought close to isothermal compression in terms of power. As described above, the power generation system according to the present invention can further reduce the heat loss and waste heat to further increase the power generation efficiency. Further, by setting the pressure to about atmospheric pressure, it is possible to configure a system that is safer and can be reduced in scale.

  In the power generation system according to the present invention, it is preferable that the first compressor, the expander, the second compressor, and the generator are coupled to a rotating shaft of the turbine so that the power generation system can be driven by driving the turbine. Further, the power generation system according to the present invention is provided with a booster pump instead of the first compressor, and the first working fluid includes liquid, turbine, and high temperature side heat exchangers on the booster pump and low temperature side heat exchanger side. You may use the fluid which becomes gas on the side. In this case, since the pressure can be increased in a liquid state by the pressure increasing pump, energy loss can be suppressed. The first working fluid heated by the low temperature side heat exchanger may be used for heating, hot water supply, or the like. Moreover, since the 2nd working fluid expanded by the expander is low temperature, you may utilize this for cooling etc. Any heat source may be used as long as it can heat the first working fluid to such an extent that the turbine can be driven, such as a combustion furnace or solar light.

  The power generation system according to the present invention includes a working fluid, a heat insulating container, a circulation unit, a heat pump, a low temperature side heat exchanger, a high temperature side heat exchanger, an intermediate heat exchanger, and a generator, and the heat insulating container includes a liquid and a gas. The circulating fluid has a booster pump, a heat source, and a turbine, and the booster pump is provided so as to pressurize the working fluid of the liquid sent from the heat insulating container, and the heat source Is provided to heat the working fluid pressurized by the booster pump, the turbine is provided to be drivable by the working fluid heated by the heat source, and the heat pump includes a compressor, a heat radiating unit, and an expander. And the compressor is provided so as to compress the working fluid after driving the turbine and the gaseous working fluid sent from the heat insulating container, and the heat radiating portion is compressed by the compressor. The expander is provided to dissipate the heat of the working fluid, the expander is provided to expand the working fluid that dissipates heat in the heat radiating unit, and then is sent to the heat insulating container. The heat exchange between the working fluid sent from the heat insulating container to the compressor and the working fluid from the heat radiating portion toward the expander and the working fluid from the booster pump toward the heat source, The high temperature side heat exchanger is provided to heat the working fluid from the boost pump toward the heat source, and the high temperature side heat exchanger includes the working fluid from the turbine toward the compressor, and the low temperature side heat from the boost pump toward the heat source. Heat exchange is performed with the working fluid downstream from the exchanger, and the working fluid is provided to heat the working fluid from the booster pump toward the heat source. Heat exchange is performed between the working fluid from the compressor toward the heat radiating unit, and the working fluid between the low temperature side heat exchanger and the high temperature side heat exchanger from the booster pump toward the heat source, The working fluid from the booster pump toward the heat source may be heated and vaporized, and the generator may be provided so as to be able to generate power by driving the turbine.

  In this configuration, the working fluid becomes liquid on the booster pump and low-temperature side heat exchanger side upstream from the intermediate heat exchanger, and becomes gas on the downstream high-temperature side heat exchanger and turbine side. The voltage can be boosted in the state. By heating the pressurized working fluid in a low temperature side heat exchanger, the temperature can be raised to near the boiling point. Further, by further heating with an intermediate heat exchanger and vaporizing the working fluid at a temperature of about room temperature, it is possible to obtain a high-pressure gaseous working fluid while suppressing energy loss.

  Since the gas working fluid after driving the turbine is recondensed and liquefied by the heat pump, the heat efficiency is good. Moreover, since the compression heat when compressing a gaseous working fluid is used for vaporization of the working fluid in a circulation part, thermal efficiency is further improved. By utilizing the liquefaction / vaporization of the working fluid, it is possible to reduce the temperature difference of the working fluid in the booster pump, low-temperature side heat exchanger, intermediate heat exchanger, and heat pump. A typical heat engine.

  The working fluid is made of, for example, carbon dioxide or water. If the working fluid consists of carbon dioxide, it will not thermally decompose at high temperatures, it will not dissolve other materials, it will not conduct electricity, it will be chemically stable, so it will not erode metals and extend the life of the system. Can do. Further, post-treatment of carbon dioxide after use is not necessary. Since carbon dioxide is liquefied and vaporized at an appropriate pressure and temperature around room temperature, the thermal efficiency of the entire system can be increased. Since the vapor pressure of carbon dioxide at room temperature is high, the entire system can be downsized even if it has a large output.

  ADVANTAGE OF THE INVENTION According to this invention, the electric power generation system which can reduce heat_generation | fever loss and waste heat and can improve electric power generation efficiency more can be provided.

It is a block diagram which shows the electric power generation system of the 1st Embodiment of this invention. It is a block diagram which shows the electric power generation system of the 2nd Embodiment of this invention. It is a block diagram which shows the electric power generation system of the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a power generation system according to a first embodiment of the present invention.
As shown in FIG. 1, the power generation system 10 includes a circulation unit 11, a heat pump 12, a low temperature side heat exchanger 13, a high temperature side heat exchanger 14, and a generator 15. The power generation system 10 is suitably used for small / medium power.

  As shown in FIG. 1, the circulation unit 11 includes a first compressor 21, a heat source 22, and a turbine 23. The circulation unit 11 includes a first working fluid that is a gas that circulates between the first compressor 21 and the turbine 23. The first compressor 21 is provided to compress the first working fluid. The first compressor 21 is configured such that the first working fluid after compression reaches about room temperature. The heat source 22 is provided to heat the first working fluid compressed by the first compressor 21. The turbine 23 is a gas turbine and is provided so as to be driven by a first working fluid heated by the heat source 22.

  As shown in FIG. 1, the heat pump 12 includes an expander 24, a second compressor 25, and a heat radiating unit 26. Further, the heat pump 12 has a gaseous second working fluid that circulates between the expander 24 and the second compressor 25. The expander 24 is provided to expand the second working fluid. The second compressor 25 is provided so as to compress the second working fluid expanded by the expander 24. The second compressor 25 is configured to suppress the temperature rise by lowering the compression ratio. The heat dissipating unit 26 is provided to dissipate heat of the second working fluid compressed by the second compressor 25. The second compressor 25 of the heat pump 12 operates near room temperature.

  As shown in FIG. 1, the low-temperature side heat exchanger 13 includes a first working fluid from the turbine 23 toward the first compressor 21, a second working fluid from the heat dissipating unit 26 toward the expander 24, and a first from the expander 24. Heat exchange is performed between the second working fluid heading toward the second compressor 25 and the second working fluid heading toward the second compressor 25 from the expander 24 is heated. At this time, the temperature of the second working fluid at the outlet of the expander 24 is lowered so that the temperature of the first working fluid after compression by the first compressor 21 becomes room temperature. The high temperature side heat exchanger 14 includes a first working fluid upstream from the low temperature side heat exchanger 13 that travels from the turbine 23 toward the first compressor 21, and a first working fluid that travels from the first compressor 21 toward the heat source 22. Heat exchange is performed between the first compressor 21 and the heat source 22 so as to heat the first working fluid. The generator 15 is provided so as to be able to generate power by driving the turbine 23.

  As shown in FIG. 1, the power generation system 10 includes a first compressor 21, an expander 24, a second compressor 25, and a generator 15 coupled to a rotating shaft of the turbine 23 so that the power generation system 10 can be driven by driving the turbine 23. Yes.

Next, the operation will be described.
The power generation system 10 can generate power by driving the generator 15 with the turbine 23 as follows. First, in the circulation part 11, the 1st working fluid compressed with the 1st compressor 21 is heated by heat exchange with the high temperature side heat exchanger 14, and the temperature which can drive the turbine 23 with the heat source 22, for example, 500- Further heating to about 1000 ° C. The turbine 23 is driven by the heated first working fluid, and the generator 15 is thereby driven to generate power. The first working fluid that has driven the turbine 23 is deprived of heat by heat exchange in the high-temperature side heat exchanger 14, and is further deprived of heat by heat exchange in the low-temperature side heat exchanger 13. The first working fluid whose temperature has decreased is compressed again by the first compressor 21 and travels toward the turbine 23.

  Next, in the heat pump 12, the second working fluid expanded by the expander 24 is heated by heat exchange in the low temperature side heat exchanger 13 and further compressed by the second compressor 25. The compressed second working fluid dissipates heat at the heat dissipating section 26 to lower the temperature, and further, heat is taken away by heat exchange at the low temperature side heat exchanger 13 to lower the temperature. The second working fluid whose temperature has decreased is expanded again by the expander 24 and travels to the second compressor 25. Thus, the power generation system 10 can increase the power generation efficiency by using the heat pump 12, the high temperature side heat exchanger 14, and the low temperature side heat exchanger 13.

  Since the power generation system 10 operates the second compressor 25 of the heat pump 12 near room temperature, it is possible to increase the thermal efficiency, and the heat dissipation from the heat radiating unit 26 is efficient for heating, hot water supply, temperature rise of the first working fluid, and the like. Can be used well. Since the compression ratio in the second compressor 25 of the heat pump 12 is low and the temperature rise is suppressed, the compression efficiency can be increased. Further, since the first compressor 21 of the circulation unit 11 is compressed from a low temperature, loss due to heat generation can be reduced. Since a high-pressure first working fluid can be obtained using the second working fluid having a low compression ratio, it can be approximated to isothermal compression. As described above, the power generation system 10 can further reduce power generation loss and waste heat, thereby further improving power generation efficiency.

FIG. 2 shows a power generation system 30 according to the second embodiment of the present invention.
As shown in FIG. 2, the power generation system 30 includes a heat insulating container 31, a circulation unit 11, a heat pump 12, a low temperature side heat exchanger 13, a high temperature side heat exchanger 14, an intermediate heat exchanger 32, and a generator 15. ing. The power generation system 30 is preferably used for cogeneration. In the following description, the same apparatus as that of the first embodiment of the present invention is denoted by the same reference numeral, and redundant description is omitted.

  As shown in FIG. 2, the heat insulating container 31 can store the first working fluid in a liquid state. The first working fluid in the circulation unit 11 is made of a fluid such as water that liquefies and vaporizes at an appropriate pressure and temperature near normal temperature. The circulation unit 11 is provided with a booster pump 33 instead of the first compressor 21.

  As shown in FIG. 2, the low temperature side heat exchanger 13 includes a first working fluid from the booster pump 33 toward the heat source 22, a second working fluid sent from the expander 24 to the compressor 25, and a heat insulating container 31 from the turbine 23. Heat exchange between the first working fluid heading toward the heat source and the second working fluid heading toward the expander 24 from the heat radiating unit 26, and the first working fluid heading from the booster pump 33 toward the heat source 22 and the expander 24 toward the compressor 25. It is provided to heat the second working fluid to be sent.

  As shown in FIG. 2, the intermediate heat exchanger 32 includes a second working fluid of the heat radiating unit 26 and a first heat exchanger 13 between the low-temperature side heat exchanger 13 and the high-temperature side heat exchanger 14 that are directed from the booster pump 33 toward the heat source 22. Heat exchange is performed with one working fluid, and the first working fluid traveling from the booster pump 33 toward the heat source 22 is heated and vaporized.

  In the power generation system 30, the first working fluid is liquid on the upstream side of the booster pump 33 and the low temperature side heat exchanger 13 upstream of the intermediate heat exchanger 32, and gas on the downstream side of the turbine 23 and the high temperature side heat exchanger 14. It is comprised so that it may become. In the power generation system 30, the expander 24, the compressor 25, and the power generator 15 are connected to the rotating shaft of the turbine 23 so that the power generation system 30 can be driven by the turbine 23.

Next, the operation will be described.
In the power generation system 30, the first working fluid can be boosted in a liquid state by the booster pump 33, so that energy loss can be suppressed. As shown in FIG. 2, in the power generation system 30, the first working fluid heated by the low-temperature side heat exchanger 13 can be used for heating or hot water supply. Moreover, since the 2nd working fluid expanded by the expander 24 is low temperature, this can be utilized for air_conditioning | cooling. Thus, the power generation system 30 can constitute a highly efficient co-generation system by generating heat absorption and heat with a heat pump and simultaneously enabling power generation.

FIG. 3 shows a power generation system 50 according to the third embodiment of the present invention.
As shown in FIG. 3, the power generation system 50 includes a working fluid 51, a heat insulating container 31, a circulation unit 11, a heat pump 12, a low temperature side heat exchanger 13, a high temperature side heat exchanger 14, an intermediate heat exchanger 32, and a generator 15. And have. The power generation system 50 is suitably used for large power. In the following description, the same reference numerals are assigned to the same devices as those in the first and second embodiments of the present invention.

  As shown in FIG. 3, the working fluid 51 is made of carbon dioxide. The heat insulating container 31 stores a liquid that is the working fluid 51 and gaseous carbon dioxide. The circulation unit 11 includes a booster pump 33, a heat source 22, and a turbine 23. The booster pump 33 is provided to increase the pressure of the liquid carbon dioxide sent from the heat insulating container 31. The heat source 22 is provided so as to heat the carbon dioxide compressed by the booster pump 33 and then vaporized. The turbine 23 is a gas turbine and is provided so as to be driven by carbon dioxide heated by the heat source 22.

  As shown in FIG. 3, the heat pump 12 includes a compressor 25, a heat radiating unit 26, and an expander 24. The compressor 25 is provided to compress the gaseous carbon dioxide after driving the turbine 23 and the gaseous carbon dioxide sent from the heat insulating container 31. The compressor 25 is configured to suppress the temperature rise by lowering the compression ratio. The heat dissipating unit 26 is provided to dissipate the heat of carbon dioxide compressed by the compressor 25. The expander 24 is provided so as to expand the carbon dioxide that has dissipated heat in the heat dissipating unit 26 and liquefy a part thereof, and then send it to the heat insulating container 31. The compressor 25 of the heat pump 12 is designed to operate near room temperature.

  As shown in FIG. 3, the low temperature side heat exchanger 13 includes carbon dioxide sent from the heat insulating container 31 to the compressor 25, carbon dioxide directed from the heat radiating unit 26 to the expander 24, and carbon dioxide directed from the booster pump 33 to the heat source 22. Heat exchange is performed with carbon, and a temperature difference is provided to carbon dioxide heading from the booster pump 33 toward the heat source 22. The high temperature side heat exchanger 14 exchanges heat between carbon dioxide from the turbine 23 toward the compressor 25 and carbon dioxide downstream from the low temperature side heat exchanger 13 from the pressure pump 33 toward the heat source 22 to increase the pressure. It is provided to heat carbon dioxide from the pump 33 toward the heat source 22.

  As shown in FIG. 3, the intermediate heat exchanger 32 includes carbon dioxide from the compressor 25 toward the heat radiating unit 26, and the low-temperature side heat exchanger 13 and the high-temperature side heat exchanger 14 from the booster pump 33 toward the heat source 22. Heat exchange is performed with carbon dioxide therebetween, and the carbon dioxide heading from the booster pump 33 toward the heat source 22 is heated and vaporized. The generator 15 is provided so as to be able to generate power by driving the turbine 23.

  The power generation system 50 is configured such that carbon dioxide becomes liquid on the upstream side of the booster pump 33 and the low-temperature side heat exchanger 13 upstream of the intermediate heat exchanger 32 and gas on the downstream side of the turbine 23 and the high-temperature side heat exchanger 14. It is configured. In the power generation system 50, the expander 24, the compressor 25, and the generator 15 are coupled to the rotating shaft of the turbine 23 so that the power generation system 50 can be driven by the turbine 23.

Next, the operation will be described.
The power generation system 50 can generate electricity by driving the generator 15 with the turbine 23 as follows. First, in the circulation unit 11, the liquid carbon dioxide sent from the heat insulating container 31 is pressurized by the booster pump 33, heated by heat exchange at the low temperature side heat exchanger 13, and heat exchanged by the intermediate heat exchanger 32. Is further heated and vaporized. The vaporized carbon dioxide is heated by heat exchange in the high temperature side heat exchanger 14, and the turbine 23 is driven by the carbon dioxide heated to a temperature at which the turbine 23 can be driven by the heat source 22, thereby driving the generator 15. Power generation.

  The carbon dioxide that has driven the turbine 23 is deprived of heat by heat exchange in the high-temperature side heat exchanger 14 and drops to near room temperature, where it is mixed with gaseous carbon dioxide sent from the heat insulating container 31 and mixed with the heat pump 12. Sent to. The carbon dioxide sent to the heat pump 12 is compressed by the compressor 25, deprived of heat by heat exchange in the intermediate heat exchanger 32, dissipated in the heat radiating section 26, and further heat exchanged in the low temperature side heat exchanger 13. As a result, heat is taken away and the temperature falls to the liquefaction temperature. The carbon dioxide whose temperature has decreased is expanded by the expander 24 and partly liquefied, and heads toward the heat insulating container 31. Among the carbon dioxide contained in the heat insulating container 31, the liquid carbon dioxide is directed to the booster pump 33, and the gaseous carbon dioxide is heated by the low temperature side heat exchanger 13 and then mixed with the carbon dioxide driving the turbine 23. To the compressor 25. Thus, the power generation system 50 can increase the power generation efficiency by using the heat pump 12, the high temperature side heat exchanger 14, the intermediate heat exchanger 32, and the low temperature side heat exchanger 13.

  Since the power generation system 50 operates the heat pump 12 near room temperature, the thermal efficiency can be increased. Since the compression ratio in the compressor 25 of the heat pump 12 is low and the temperature rise is suppressed, the compression efficiency can be increased. Since high-pressure carbon dioxide in the circulation part 11 can be obtained using carbon dioxide having a low compression ratio in the heat pump 12, it is possible to approach isothermal compression. As described above, the power generation system 50 can further reduce the heat loss and waste heat to further increase the power generation efficiency.

  In the power generation system 50, carbon dioxide used as the working fluid 51 is not thermally decomposed even at a high temperature, does not dissolve other substances, is not electrically conductive, and is chemically stable, so that it does not erode a metal, The life of the system can be extended. Further, post-treatment of carbon dioxide after use is not necessary. Since carbon dioxide is liquefied and vaporized at an appropriate pressure and temperature around room temperature, the thermal efficiency of the entire system can be increased. Since the vapor pressure of carbon dioxide is high at room temperature, the entire system can be downsized.

  In the power generation system 50, the booster pump 33 can boost the pressure of carbon dioxide in a liquid state. The pressurized liquid carbon dioxide is heated by the low temperature side heat exchanger 13 and further heated by the intermediate heat exchanger 32 to vaporize the carbon dioxide at a temperature of about room temperature, thereby suppressing energy loss and increasing the pressure. Gaseous carbon dioxide can be obtained.

  Since the power generation system 50 uses the heat pump 12 to recondense and liquefy gaseous carbon dioxide after the turbine 23 is driven, it has high thermal efficiency. Moreover, since the compression heat when compressing gaseous carbon dioxide is used for vaporization and temperature rise of carbon dioxide in the circulation part 11, thermal efficiency is further improved. By utilizing the liquefaction / vaporization of carbon dioxide, the temperature difference between the high pressure side and the low pressure side of carbon dioxide in the boost pump 33, the low temperature side heat exchanger 13, the intermediate heat exchanger 32, and the heat pump 12 can be reduced. It is possible to construct an ideal heat engine that is heat efficient and close to the Carnot cycle.

In the specific example shown in FIG. 3, the pressure inside the heat insulating container 31 is 2 MPa, and the pressure of the liquid carbon dioxide pressurized by the booster pump 33 is 10 MPa. The pressure P ₂ of gaseous carbon dioxide before driving the turbine 23 is 10 MPa, the temperature T ₂ is 1073 K, the pressure P ₁ of gaseous carbon dioxide after driving the turbine 23 is 2 MPa, and the temperature T ₁ is 840 K. The temperature T ₆ of gaseous carbon dioxide toward the compressor 25 of the heat pump 12 is 300K. The temperature T ₃ of gaseous carbon dioxide from the low temperature side heat exchanger 13 toward the expander 24 is 253 K, and the pressure P ₃ is 3 MPa. The pressure _{P 4} of the liquid carbon dioxide flowing from the expander 24 to the insulated container 31 is 2 MPa.

At this time, assuming that the temperature of the liquid carbon dioxide from the expander 24 toward the heat insulating container 31 is T ₄ and the temperature of the gaseous carbon dioxide in the heat radiating section 26 is T ₅ , the efficiency η of the heat pump 12 is T ₅ = T ₆ / (P ₄ / P ₃ ) ^{(κ-1) / κ} , T ₄ = T ₃ / (P ₃ / P ₄ ) ^{(κ-1) / κ} ,
η = (T ₃ + T ₄ ) / {(T ₅ + T ₆ ) − (T ₃ + T ₄ )}
≒ 3.31
It becomes. Here, the specific heat ratio κ = 1.314 (value of 250K) and κ = 1.288 (value of 300K). Since the heat of vaporization at 2 MPa and 253 K is 280 J / g, the energy of the heat pump 12 required for recondensation is 280 / 3.31≈84.6 J / g.

The endothermic energy of the turbine 23 is κ = 1.186 and the constant pressure specific heat C _p = 1.204 (value of 900K).
(T ₂ −T ₁ ) C _p = {T ₂ −T ₂ / (P ₂ / P ₁ ) ^{(κ−1) / κ} } C _p
= 280.5J / g
It becomes.
The work of the booster pump 33 when increasing the pressure of liquid carbon dioxide from 2 MPa to 10 MPa is as follows:
Work of pressurizing pump 33 = pressure difference (N ² ) × distance (m) / density (g / cm ³ )
= (1000-200) 0.01 / 1.56
≒ 5.1
It becomes.
Therefore, if this amount is reflected in the thermal efficiency,
Thermal efficiency = (280.5-84.6-5.1) /280.5
= 0.68
It becomes.

Next, the required air volume of the expander 24 is obtained. Assuming that κ = 1.314 and C _p = 0.791 (value of 250K), the endothermic amount of the expander 24 per air volume is
(T ₃ −T ₄ ) C _p = {T ₃ −T ₃ / (P ₄ / P ₃ ) ^{(κ−1) / κ} } C _p
≒ 18.3 J / g
It becomes.
At this time, the heat of vaporization / endothermic amount is 280 / 18.3 = 15.4≈16. Therefore, if there is an adiabatic expansion amount 16 times the air volume of the turbine 23, recondensation is possible.
These calculations do not include conversion efficiency, but if the output is 10,000 kW or more, 85 to 90% is possible. Further, the temperature at the inlet of the turbine 23 is determined by the heat resistance of the material, but if this can be further increased, the efficiency can be further increased.

DESCRIPTION OF SYMBOLS 10 Power generation system 11 Circulation part 12 Heat pump 13 Low temperature side heat exchanger 14 High temperature side heat exchanger 15 Generator 21 1st compressor 22 Heat source 23 Turbine 24 Expander 25 Second compressor (compressor)
26 Heat dissipation part

Claims (2)

It has a circulation part, a heat pump, a low temperature side heat exchanger, a high temperature side heat exchanger, and a generator,
The circulation unit includes a first compressor, a heat source, and a turbine, and includes a first working fluid that circulates between the first compressor and the turbine, and the first compressor includes the first working fluid. The heat source is provided to heat the first working fluid compressed by the first compressor, and the turbine is provided to be drivable by the first working fluid heated by the heat source. And
The heat pump has an expander, a second compressor, and a heat radiating section, and has a second working fluid that circulates between the expander and the second compressor, and the expander is the second working fluid. The second compressor is provided to compress the second working fluid expanded by the expander, and the heat radiating portion is compressed by the second compressor. To dissipate the heat of
The low temperature side heat exchanger includes the first working fluid from the turbine toward the first compressor, the second working fluid from the heat radiating portion toward the expander, and the expander to the second compressor. Heat exchanging with the second working fluid heading, provided to heat the second working fluid heading from the expander to the second compressor;
The high temperature side heat exchanger includes the first working fluid upstream from the low temperature side heat exchanger heading from the turbine toward the first compressor, and the first working fluid heading from the first compressor toward the heat source. A heat exchange between the first compressor and the heat source to heat the first working fluid,
The generator is provided so as to be able to generate power by driving the turbine.
Characteristic power generation system. A working fluid, a heat insulating container, a circulation unit, a heat pump, a low temperature side heat exchanger, a high temperature side heat exchanger, an intermediate heat exchanger, and a generator;
The heat insulating container contains the liquid and gaseous working fluid,
The circulation unit includes a booster pump, a heat source, and a turbine, and the booster pump is provided to compress the working fluid that is liquid sent from the heat insulating container, and the heat source is compressed by the booster pump. Provided to heat a fluid, and the turbine is provided to be drivable by the working fluid heated by the heat source,
The heat pump includes a compressor, a heat radiating unit, and an expander, and the compressor is provided to compress the working fluid after driving the turbine and the working fluid of gas sent from the heat insulating container, The heat dissipating part is provided to dissipate heat of the working fluid compressed by the compressor, and the expander expands the working fluid dissipated heat by the heat dissipating part and then sends it to the heat insulating container. Provided,
The low-temperature side heat exchanger includes a gap between the working fluid sent from the heat insulating container to the compressor, the working fluid going from the heat radiating unit to the expander, and the working fluid going from the booster pump to the heat source. Heat exchange is performed to provide a temperature difference in the working fluid from the booster pump toward the heat source,
The high temperature side heat exchanger performs heat exchange between the working fluid from the turbine toward the compressor and the working fluid downstream from the low temperature side heat exchanger from the boost pump toward the heat source. , Provided to heat the working fluid from the booster pump to the heat source,
The intermediate heat exchanger includes the working fluid from the compressor toward the heat radiating unit, and the working fluid between the low temperature side heat exchanger and the high temperature side heat exchanger from the booster pump to the heat source. Heat exchange between and is provided to heat and vaporize the working fluid from the booster pump toward the heat source,
The generator is provided so as to be able to generate power by driving the turbine.
Characteristic power generation system.

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