JP2012251456A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the following problem of a power generation system: when geothermal heat is used for power generation, the system is available only in the area where the geothermal heat can be obtained.SOLUTION: This power generation system includes a heat pump having a compressor, a generator for supplying electric power by power of a turbine to be driven by energy of a working medium heated and vaporized by the heat pump, a circulating means for sending out the working medium from the turbine, and a control part. An organic compound whose absolute saturated vapor pressure in 90°C is 0.3 MPa or more is used as the working medium. CO2 is used as a refrigerant. A scroll turbine or a screw turbine is used as a turbine. Inlet pressure that is a pressure of the working medium in an inlet is set to the saturated vapor pressure or less of the working medium in the inlet temperature. Sum electric power as a sum of compressor driving electric power, circulating means driving electric power and control part electric power for the control part is supplied. The system operates under the condition that generated electric power is set to be larger than the sum electric power.

Description

  The present invention provides an external air heat exchanger that heats and vaporizes a refrigerant, a compressor that compresses the refrigerant, a working medium heat exchanger that heats a working medium by the compressed refrigerant, and the refrigerant from the working medium heat exchanger. A heat pump comprising a recovery path that is recovered under reduced pressure and led to an inlet of a refrigerant heating flow path of the outside air heat exchanger and the refrigerant, a turbine that is powered by the thermal energy of the working medium heated by the heat pump, and the turbine A working medium power generation cycle section including circulation means for sending the working medium discharged from the discharge port of the working medium to the working medium heat exchanger, a generator for supplying generated power by the power of the turbine, the heat pump, and the working medium A control unit that controls the power generation cycle unit, and is supplied to the control unit, the driving power for the compressor, the driving power for the circulation means, and Power is supplied as a sum a is the sum power of the control unit for electric power, to a power generation system is operated at a true generated power acquisition conditions the total power from the generated power is set to be larger.

  Conventionally, power generation systems that efficiently generate power have been proposed (see, for example, Patent Document 1 and Patent Document 2).

  In Patent Document 1 and Patent Document 2, the configuration of a power generation system improved so as to improve the utilization efficiency of heat source energy is shown.

JP 2009-221961 A JP 2009-22123 A

Although Patent Document 1 can improve the utilization efficiency of heat source energy and the power generation output, there are the following problems.
For example, when geothermal is used as the heat source energy, it can be used only in an area where geothermal heat can be obtained.
Incidentally, even if the expansion efficiency (power conversion efficiency) of the turbine that drives the generator is improved, only an efficiency of about 0.6 to 0.7 can be obtained. If it is covered by energy from fuel supply, system efficiency exceeding 1 cannot be obtained.

On the other hand, in Patent Document 2, a liquid is evaporated by a heat pump to form a gas, and a power generator is driven by a turbine that uses the energy of the gas as power.

In Patent Document 2, if the product of the COP of the heat pump and the efficiency η when the generator is driven by the turbine to generate power, and the value of COP × η exceeds 1, power greater than the power required for power generation is obtained. However, no practical examples have been described.

That is, when the heating temperature by the heat pump is 100 ° C. or less, for example, when boiling water in a vacuum, the boiling point can be lower than 100 ° C., but the turbine outlet pressure cannot be lower than zero. The differential pressure between the inlet and the outlet is at most 0.1 MPa. When the differential pressure between the inlet and the outlet is 0.1 MPa, the power generation of 0.3 shown in the example of Patent Document 2 is shown. Efficiency is not obtained.

Further, if the temperature of the heat exchanger on the high temperature side in the heat pump is increased in order to increase the differential pressure between the inlet and the outlet in the turbine, the COP of the heat pump is lowered. The product of the efficiency η and the value of COP × η when power is driven to generate power will not exceed 1.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power generation system capable of generating power efficiently regardless of the region.

A first characteristic configuration of the present invention includes an outside air heat exchanger that includes a refrigerant heating channel, absorbs heat from outside the system, transmits the refrigerant to the refrigerant flowing through the refrigerant heating channel, and vaporizes the refrigerant, and an outlet of the refrigerant heating channel A compressor that compresses the refrigerant from the medium, a working medium heat exchanger that heats the working medium with the compressed refrigerant, and a refrigerant that is discharged from the working medium heat exchanger after the working medium is heated. A recovery path that leads to an inlet of a refrigerant heating channel of the outside air heat exchanger, and the refrigerant path of the outside air heat exchanger, the compressor, the working medium heat exchanger, the recovery path, and the refrigerant Configure the heat pump
And a turbine having an inlet and an outlet, wherein the working medium flowing through the working medium flow path of the working medium heat exchanger is vaporized by heating by the heat pump, and after being vaporized, the outlet of the working medium flow path The working medium discharged from the inlet is introduced into the inlet and discharged from the outlet, so that the turbine is powered by the heat energy of the vaporized working medium, and power is generated by the power. An operation system comprising a circulation means for delivering the working medium discharged from the discharge port to an inlet of the working medium flow path, and comprising the working medium flow path, the turbine, the circulation means, and the generator. Configure the medium power generation cycle section,
A control unit for controlling the heat pump and the working medium power generation cycle unit;
Compressor driving power for driving the compressor, circulating means driving power for driving the circulating means, and power as control section power supplied to the control section are supplied,
True generated power that is an operating condition that is set such that the generated power generated by the generator is larger than the total power that is the sum of the compressor driving power, the circulation means driving power, and the control unit power A power generation system configured to operate under acquisition conditions,
An organic compound whose saturated vapor pressure at 90 ° C. is 0.3 MPa or more is used as the working medium, the refrigerant is CO2, and the turbine is a scroll turbine or a screw turbine.
The true generated power acquisition condition is that the inlet temperature, which is the temperature of the working medium at the inlet, is approximately 90 ° C., and the inlet pressure, which is the pressure of the working medium, at the inlet is the inlet temperature. It is characterized in that it is configured so as to be set to operating conditions that are not higher than the saturated vapor pressure of the working medium.

That is, the operating conditions are set so that the generated power is larger than the power consumed in the power generation system in order to operate the power generation system.

  According to the first characteristic configuration of the present invention, heat from the outside of the system can be converted into electric power even in the case of outside air that is not particularly hot, substantially without supply of electric power or fuel from the outside. Electric energy can be obtained without regional restrictions and without discharging global warming gas. In addition, since a refrigerant suitable for a heat pump is used as the refrigerant, a working medium suitable for the working medium power generation cycle unit is used as the working medium, and different substances can be used as the refrigerant and the working medium, the optimum power generation system. Is easy to configure.

Incidentally, the power generation system according to the present invention is not a permanent engine that violates the laws of nature, and the solar panel converts sunlight energy into electric energy, whereas the power generation system according to the present invention A technique for converting thermal energy into electrical energy is provided.

  According to a second characteristic configuration of the present invention, in addition to the first characteristic configuration described above, an auxiliary heat source for heating the working medium before being introduced into the introduction port is provided.

  According to the second characteristic configuration of the present invention, in addition to the effect of the first characteristic configuration described above, the working medium can be sufficiently heated by the heating of the auxiliary heat source. The adverse effect resulting from the increase in the liquid phase ratio of the working medium due to the vapor can be reduced. In addition, since a working medium having a slightly higher boiling point can be used, the conditions for selecting the working medium are eased.

  According to a third feature of the present invention, in addition to the second feature described above, the recovery path is formed by exhaust heat remaining after heating the working medium before the auxiliary heat source is introduced into the introduction port. It is characterized by heating the flowing refrigerant.

  According to the third characteristic configuration of the present invention, in addition to the effect of the second characteristic configuration described above, the exhaust heat remaining after the auxiliary heat source heats the working medium is used for heating the refrigerant flowing through the recovery path. Since the exhaust heat remaining after heating the medium is reduced by heating the refrigerant, the heat efficiency by heating the auxiliary heat source can be increased.

  According to a fourth feature configuration of the present invention, in addition to any of the first feature configuration to the third feature configuration described above, after the refrigerant flowing through the recovery path absorbs heat from outside the system by the outside air heat exchanger, A cooling unit that cools the working medium discharged from the discharge port with the refrigerant is provided.

  According to the fourth feature configuration of the present invention, in addition to the effect of any one of the first feature configuration to the third feature configuration, the remaining energy of the working medium discharged from the discharge port is effectively reused. It will be possible. Furthermore, since the refrigerant can absorb heat from outside the system by the outside air heat exchanger before the working medium discharged from the discharge port is cooled in the cooling unit, the system in the outside air heat exchanger Since the temperature difference between the heat from the outside and the refrigerant is large and the coefficient of performance (COP) in the heat pump is high, a more efficient power generation system can be obtained.

  According to a fifth feature of the present invention, in addition to any of the first to fourth features described above, a check valve for preventing a backflow of the working medium from the working medium flow path to the circulation means is provided. It is characterized by

  According to the fifth feature configuration of the present invention, in addition to the effect of any one of the first feature configuration to the fourth feature configuration, the pressure of the working medium increased by heating by the heat pump in the working medium heat exchanger. When the pressure becomes higher than the discharge pressure of the circulation means, it is possible to avoid inconveniences caused by the backflow of the working medium.

The figure which shows the structure in embodiment The figure which shows the efficiency of the generator in the execution example Diagram showing COP of heat pump

[First Embodiment]
Hereinafter, based on the drawings, a first embodiment in which a scroll turbine is used with n-butane (normal butane) as a medium in the present invention will be described. When i-butane (isobutane) is used as the working medium, although i-butane is somewhat different from n-butane in physical properties, the results are almost the same. Therefore, the working medium is n-butane and i-butane. Any of these may be used, and n-butane and i-butane may be mixed and used.

  In the following description, when the pressure is expressed, the absolute pressure is the absolute pressure based on the vacuum, the gauge pressure is the relative pressure based on the atmospheric pressure, and the reference atmospheric pressure is the standard atmospheric pressure. (1 atm) is not used, and for the sake of convenience, it is expressed as a relative pressure when the reference atmospheric pressure is set to 0.1 MPa, as can be explained by numerical values having no fractions in the following description.

In the system shown in FIG.
H1) A low-temperature / low-pressure (for example, −10 ° C., absolute pressure 3 MPa) refrigerant (CO 2 in this embodiment) absorbs heat from the outside air A in the outside air heat exchanger 1 and is cooled / low-pressure (for example, 7 ° C., absolute pressure). 3 MPa) gas. (This example assumes a winter season when the COP of the heat pump decreases, and the -10 ° C refrigerant becomes a 7 ° C gas.)

  Thereafter, when the working medium is cooled by the condenser 7, thermal energy is obtained and the temperature rises. (For example, it becomes a gas of 30 ° C. and an absolute pressure of 3 MPa.)

  Note that the CO2 in the present embodiment may be referred to as a heat medium because it is used for the purpose of heating a working medium, which will be described later. The CO2 is called a refrigerant.

Thereafter, the refrigerant whose temperature has risen by obtaining thermal energy when the working medium is cooled by the condenser 7 is exhaust gas after the working medium is heated by exhaust gas from a burner (auxiliary heat source H) described later (residual exhaust heat). ) Further increases the temperature. (For example, it becomes 32 ° C.)

  H2) Supercritical state of high-temperature and high-pressure (for example, 97 ° C., absolute pressure of 10 MPa) when a low-temperature / low-pressure gaseous refrigerant is adiabatically compressed by the compressor 2 (a supercritical state is a state between gas and liquid) become.

  In this embodiment, electric power for the compressor 2 is supplied from the battery B via the compressor inverter INV1 whose output is controlled by the control unit CONT.

  H3) The heat energy of the refrigerant in the supercritical state is transmitted as heat energy to the working medium (in this embodiment, n-butane (normal butane)) in the working medium heat exchanger 3, and the temperature of the refrigerant is lowered to normal temperature / high pressure ( For example, 35 ° C. and absolute pressure 10 MPa).

  H4) The refrigerant is depressurized by the expansion valve 4, and becomes low temperature and low pressure (for example, −10 ° C., absolute pressure 3 MPa).

  A heat pump cycle is constituted by the above H1) to H4). In the following description, the heat pump cycle of H1) to H4) may be hereinafter referred to as a CO2 heat pump cycle.

  S1) The working medium (n-butane in this embodiment) of the liquid (30 ° C. in this embodiment) pumped by the pump 5 is heated to a high temperature (90 ° C. in this embodiment) by the working medium heat exchanger 3.

  Further, the working medium (n-butane in this embodiment) is heated by the burner (auxiliary heat source H) to become superheated steam.

  At this time, when the temperature of the temperature sensor TH (not shown) for detecting the temperature of the working medium after being heated by the working medium heat exchanger 3 does not exceed 100 ° C., a power detection unit (see FIG. The control unit CONT controls the inverter INV1 for the compressor so that the output of INV1 by the rated power is 2 kW, and the burner (auxiliary heat source H) has an input of 2 kW which is the rated input. An input controller (not shown) of the auxiliary heat source H) is controlled.

  On the other hand, when the temperature of the temperature sensor TH (not shown) exceeds 100 ° C., the control unit CONT controls the compressor inverter INV1 and reduces the input of the burner (auxiliary heat source H) so as to decrease the output of INV1. Controls a controller (not shown).

The reason why the temperature of the temperature sensor TH is controlled to be 100 ° C. or less and the input controller (not shown) of the burner (auxiliary heat source H) is controlled is that the saturated vapor pressure of the working medium is a gauge pressure of 1. Since the temperature at which 39 MPa (= absolute pressure 1.49 MPa) is 100 ° C., by controlling the temperature of the temperature sensor TH to be 100 ° C. or less, the relative pressure of the saturated vapor pressure of the working medium to the atmospheric pressure is controlled. This is to prevent the gauge pressure from significantly exceeding 1.39 MPa and limit an excessive increase in pressure of the working medium.

  That is, when the temperature of the temperature sensor TH is lower than 100 ° C., the output of the compressor inverter INV1 is set to a rated output of 2 kW, and the input of the burner (auxiliary heat source H) is set to a rated input of 2 kW. When the temperature of the temperature sensor TH is higher than 100 ° C., the output of the compressor inverter INV1 and the input of the burner (auxiliary heat source H) are decreased, so that the temperature of the working medium when the working medium is vaporized is In the example, the temperature is controlled to be 100 ° C. or lower.

  Further, the control unit CONT keeps the detection temperature T1 of the temperature detector TH (not shown) constant (in this embodiment, 90 ° C., which is the temperature at which the saturated vapor pressure of n-butane becomes a gauge pressure of 1.127 MPa). Further, by adjusting the opening degree of the motor valve 8, the temperature of the working medium is kept substantially constant and a high pressure (in this embodiment, a gauge pressure of 0.9 MPa). (N-butane is sufficiently vaporized because the gauge pressure 1.127 MPa (= absolute pressure 1.227 MPa) is the saturated vapor pressure at 90 ° C.)

  More specifically, the heating amount by the CO2 heat pump cycle in the working medium heat exchanger 3 is the rated heating amount corresponding to the output 2 kW of the inverter INV1 for the compressor and the input 2 kW of the burner (auxiliary heat source H). The flow rate per hour of the working medium flowing through the working medium flow path in the working medium heat exchanger 3 is reduced by reducing the opening of the working medium heat exchanger 3, and the working medium flow rate by the temperature detector TH (not shown) at the outlet of the working medium flow path The detected temperature of the working medium by the pressure sensor PS (not shown) at the outlet of the working medium flow path can be adjusted to increase as the detected temperature T1 increases, and the working medium heat can be increased by increasing the opening of the motor valve 8. The flow rate per hour of the working medium flowing through the working medium flow path in the exchanger 3 increases, and the temperature detector TH ( The temperature T1 detected by the working medium can be adjusted to be lowered while the detected temperature T1 of the working medium by the pressure sensor PS (not shown) at the outlet of the working medium flow path is lowered. The detected temperature T1 is maintained at 90 ° C.

  Further, the detected temperature T1 of the working medium by the temperature detector TH (not shown) at the outlet of the working medium flow path and the detected pressure p1 of the working medium by the pressure sensor PS (not shown) at the outlet of the working medium flow path are motorized. While controlled by the opening degree of the valve 8, the detected pressure p2 by the second pressure sensor PS2 (not shown) at the outlet (exhaust port) of the turbine 6 is controlled as follows. In this case, the motor valve 8 is preferably disposed downstream of the pump 5, and cavitation occurs due to a pressure drop in the suction portion of the pump 5 as compared with the case where the motor valve 8 is disposed upstream of the pump 5. This makes it difficult to reduce the performance of the pump 5 due to the cavitation.

  The control unit CONT is configured to detect the working medium pressure p1 (= pressure at the inlet (inlet) of the turbine 6) by the pressure sensor PS (not shown) at the outlet of the working medium flow path and the outlet (exhaust) of the turbine 6. When the differential pressure Δp = p1−p2 with respect to the detected pressure p2 by the second pressure sensor PS2 (not shown) is smaller than 0.67 MPa, the opening degree of the motor valve 8 is increased, and the differential pressure Δp = When p1-p2 is larger than 0.67 MPa, the pressure at the inlet (inlet) of the turbine 6 is controlled to be smaller than the pressure at the outlet (outlet) of the turbine 6 by controlling the opening of the motor valve 8 to be smaller. The pressure difference Δp is maintained at 0.6 MPa or higher by maintaining the pressure at a level of .67 MPa, and the efficiency of the turbine 6 is maintained.

  At this time, the opening degree of the motor valve 8 is changed, and the flow rate per hour of the working medium flowing through the working medium flow path of the working medium heat exchanger 3 is increased, so that the temperature detector TH (not shown) at the outlet of the working medium flow path When the detected temperature T1 of the working medium becomes low, the rated output of the compressor inverter INV1 is changed so as to gradually increase, and the opening degree of the motor valve 8 is changed and the working medium heat is changed. When the flow rate per hour of the working medium flowing through the working medium flow path of the exchanger 3 decreases and the detected temperature T1 of the working medium by the temperature detector TH (not shown) at the outlet of the working medium flow path becomes high, the compressor Since the control unit CONT controls the inverter INV1 so that the rated output of the inverter INV1 is gradually decreased, the temperature detector TH ( Detected temperature T1 (= the inlet of the turbine 6 (inlet) of the working medium by Shimese not) temperature in) would be maintained at a constant of about 90 ° C..

  S2) The working medium having a substantially constant pressure and a high pressure (gauge pressure of 0.9 MPa) is guided to the suction port (introduction port) side of the scroll turbine 6 and is engaged with the fixed scroll and the orbiting scroll (not shown). The swivel scroll (not shown) is swung by expanding in the spiral space formed by.

  Here, in more detail, the scroll turbine is configured such that the stationary scroll and the orbiting scroll that rises spirally from the end plate are meshed with each other to form an expansion chamber between the two, and the orbiting scroll is formed by the rotation restriction mechanism. When the expansion chamber moves while changing its volume when swung along a circular orbit under the regulation of rotation, the working medium is moved by a scroll expander having an expansion mechanism that performs suction, expansion, and discharge. It converts the thermal energy it has into mechanical energy.

Provided between the orbiting scroll (not shown) and the main bearing member (not shown) is a rotation restricting mechanism (not shown) that prevents the orbiting scroll from rotating and guides it to move in a circular orbit. The orbiting scroll is moved in a circular orbit by eccentrically driving the orbiting scroll at an eccentric shaft (not shown) at the upper end of the (not shown). As a result, the working medium is expanded utilizing the fact that the expansion chamber formed between the fixed scroll and the orbiting scroll increases in volume while moving from the central portion to the outer peripheral side, and the crankshaft is rotated.

  In addition, this kind of scroll turbine is comprised so that it may operate | move by the principle equivalent to what is used for the expander and compressor which comprise the refrigerating-cycle apparatus in an air conditioner.

As described above, the working medium that has flowed into the suction port (introduction port) of the scroll turbine 6 is expanded by rotating the crankshaft and then discharged from the discharge port (discharge port). Power recovery is performed.

  S3) As described above, the scroll turbine is swirled by the thermal energy to finish the work, become a low-temperature and low-pressure gas state, and is discharged from the discharge port (discharge port) of the scroll turbine (in this embodiment, 40 ° C. In the present embodiment, the pressure at the inlet (inlet) of the turbine 6 is maintained at 0.67 MPa higher than the pressure at the outlet (exhaust) of the turbine 6 as described above. 6 is maintained at a gauge pressure of 0.23 MPa, and the temperature at which the saturated vapor pressure of the working medium n-butane becomes a gauge pressure of 0.23 MPa (= absolute pressure of 0.33 MPa) is 35 ° C. Therefore, the gas state is maintained at a gauge pressure of 0.23 MPa and 40 ° C.) The working medium n-butane is cooled by the condenser 7 to become a liquid (30 ° C. in this embodiment). Is refrigerant becomes a low-temperature low-pressure liquid reduced by the expansion valve 4 in the CO2 heat pump cycle described above is used to cool the condenser 7.

Incidentally, the refrigerant, which has been decompressed by the expansion valve 4 in the above-described CO2 heat pump cycle and becomes a low-temperature / low-pressure liquid, is in a liquid state including a gas phase after the condenser 7 is cooled, but is 0 ° C. which is sufficiently lower than 7 ° C. Maintaining close temperature.
In the present embodiment, a refrigerant that is decompressed by the expansion valve 4 in the above-described CO2 heat pump cycle and becomes a low-temperature / low-pressure liquid is used to cool the condenser 7, but the condenser 7 is cooled. Another method may be used.

S4) The working medium that has become liquid is repeatedly pressurized to a high pressure (in this embodiment, a gauge pressure of 0.9 MPa + pressure loss in the working medium heat exchanger 3) by the pump 5, and is pumped to the working medium heat exchanger 3.
Incidentally, as described above, the motor valve 8 keeps the detected pressure p1 of the pressure sensor PS (not shown) constant at the outlet side of the working medium heat exchanger 3 (gauge pressure 0.9 MPa in this embodiment). In this embodiment, the discharge-side pressure of the pump 5 is controlled by the pressure loss in the gauge pressure 0.9 MPa + the working medium heat exchanger 3.

  In addition, the check valve CH which prevents the backflow of the working medium from the working medium flow path to the pump 5 is provided, and the working medium raised by heating by the heat pump and the auxiliary heat source H in the working medium heat exchanger 3 due to some factor. Even when the pressure becomes higher than the discharge pressure of the pump 5, it is possible to avoid inconveniences caused by the backflow of the working medium.

  The above-described S1) to S4) constitute a working medium circulation cycle. In the following description, the cycle of the working medium of S1) to S4) is hereinafter referred to as a working medium cycle, and the generator G and the working medium power generation cycle may be referred to.

  G1) The generator G is rotated by the rotational force of the scroll turbine, and power is generated by the energy recovered from the working fluid.

  G2) The electric energy generated by the generator G is stored in the battery B via the regulator R.

  G3) In this embodiment, a DC drive type brushless motor whose output is controlled by the control unit CONT is used as the pump 5 drive motor, and the power for the compressor 2 is supplied from the battery B as described above. In addition, power for the pump 5 is also supplied from the battery B. Further, power for the control unit CONT is also supplied from the battery B, and power consumed by sensors connected to the control unit CONT and actuators other than the pump 5 and the compressor 2 is also supplied from the battery B.

  G4) Further, the external power supply inverter INV2 converts the DC power from the battery B into an AC of commercial frequency (for example, 60 Hz), and AC power of the commercial frequency is supplied to the outside of the system.

  In FIG. 1, a thin solid line including an arrow indicates a flow of the refrigerant or the working medium, a broken arrow indicates a signal flow mainly, and a thick solid line arrow indicates a flow of electric power. In the present embodiment, temperature, pressure, and the like are examples, and the present invention is not limited to the above numerical values.

  In this embodiment, the working medium discharged from the discharge port (the outlet of the turbine 6) is cooled after the refrigerant absorbs heat from the outside air A in the outside air heat exchanger 1. (See Figure 1)

With this configuration, the temperature of the outside air A is low (for example, the air temperature is 7 ° C.) as in winter, and the temperature of the outside air A is the temperature of the working medium discharged from the discharge port (the outlet of the turbine 6) (second). In the case of the embodiment, for example, when the temperature is lower than 40 ° C., for example, the refrigerant absorbs heat of the outside air A in the outside air heat exchanger 1 in a state where the temperature difference between the outside air A and the refrigerant (for example, −10 ° C.) is large. Even after the temperature of the refrigerant has risen somewhat (for example, to about 7 ° C.), the refrigerant can further absorb heat from the working medium (for example, 40 ° C.) in the cooling unit 7. The coefficient of performance (COP) at is increased, and an efficient (high) power generation system can be configured.

  Here, using FIG. 2 and FIG. 3, the conversion efficiency (power generation efficiency η) from the thermodynamic energy input to the turbine 6 to the power generation energy by the generator G, and the COP (coefficient of performance) of the CO 2 heat pump cycle An explanation of the energy balance of the entire power generation system based on the above is added.

FIG. 2 is a diagram illustrating the efficiency of the generator G in the embodiment. The pressure difference between the inlet and the outlet of the turbine 6 (pressure of the inlet−pressure of the outlet) and the thermodynamics input to the turbine 6. 3 shows an example obtained by actual measurement of conversion efficiency (power generation efficiency η) from dynamic energy to power generation energy by the generator G.
FIG. 2 shows that if the pressure difference between the inlet and outlet of the turbine 6 is 0.3 MPa or more, a power generation efficiency η of 0.4 or more can be obtained.

FIG. 3 is a diagram showing a COP (coefficient of performance) of the heat pump. The temperature t1 of the outside air A in the CO2 heat pump cycle and the temperature t2 of the working medium heated by the working medium heat exchanger 3 and flowing out of the working medium heat exchanger 3 are shown. This shows an example obtained by actual measurement.
Note that, in FIG. 3, the effect of increasing the temperature of the refrigerant CO2 by obtaining thermal energy when the working medium is cooled by the condenser 7 is not taken into account, and when the working medium is cooled by the condenser 7. This represents a COP in which the heat energy obtained by the refrigerant is zero.
FIG. 3 shows that COP becomes 3 or more when t2−t1 = 83 ° C. or less. This means that when the outside air temperature is 7 ° C., the temperature t2 of the working medium flowing out from the working medium heat exchanger 3 is 90 °. If the temperature is lower than 0 ° C., the COP becomes 3 or higher even if the heat energy obtained by the refrigerant when the working medium is cooled by the condenser 7 is zero.

  Of course, when the refrigerant CO2 obtains thermal energy when the working medium is cooled by the condenser 7 and the temperature of the refrigerant CO2 rises, the heat pump recovers the exhaust heat from the turbine 6 so that the COP has a larger value. It becomes.

As described above, when the CO2 heat pump cycle and the working medium power generation cycle in which the working medium is n-butane are configured, when the COP (coefficient of performance) of the CO2 heat pump is 3, as described above, the input of the compressor 2 Is, for example, 2 kW, the energy rate (power) obtained by the working medium is 6 kW. Therefore, when the power generation efficiency of the turbine 6 to the generator G is 0.65, the power generated by the generator G is 3.9 kW. It is.
Therefore, in addition to 2 kW of the power consumption of the compressor 2, the power consumption of the pump 5 (circulation means), other actuators and the control unit CONT, and losses such as piping loss are considered, and an extra power consumption of 0.2 kW is expected. However, it is possible to supply 3.9-2-0.2 = 1.7 [kW] to the outside of the power generation system.

[Effect of heating burner (auxiliary heat source H) and effect on efficiency]
By heating the burner, the working medium can be made into sufficient superheated steam, so that adverse effects caused by the working medium becoming wet steam in the turbine 6 can be reduced.

  In addition, since the working medium having a slightly higher boiling point can be vaporized by heating the burner (auxiliary heat source H), the conditions for selecting the working medium according to the conditions resulting from the characteristics of the CO2 heat pump are relaxed, and various The working medium can be used.

  The exhaust gas (residual exhaust heat) after the burner has heated the working medium is used to heat the refrigerant after obtaining heat in the condenser 7 (cooling section), and the exhaust gas (residual exhaust heat after heating the refrigerant). Since the temperature of the heat is reduced to about 35 ° C., a highly efficient power generation system can be constructed. For example, when a gas burner using natural gas as fuel is used as the auxiliary heat source H, the gas burner is heated. The thermal efficiency can be configured to be as high as 95% based on the higher heat generation standard.

Therefore, when the input to the auxiliary heat source H (burner) is 2 kW (1720 kcal / h), the power given to the working medium is 2 × 0.95 = 1.9 kW, and this is a power generation of 0.65. Since it is converted into 1.235 kW power depending on the efficiency, the system can obtain 2.935 kW power by adding 1.235 kW to 1.7 kW that can be supplied to the outside of the power generation system by the above-mentioned CO2 heat pump. It becomes the supplyable electric power.
Therefore, the overall efficiency is
2.935 kW (suppliable power) / 2 kW (input to auxiliary heat source H) = about 1.5
Thus, high-efficiency power generation is possible with some CO2 emission, and the amount of CO2 emission can be greatly reduced.

  Of course, when the auxiliary heat source H is not used, it goes without saying that the amount of CO2 emission is zero.

[Another embodiment]
Hereinafter, other embodiments are listed.
[Another Example 1]
As in the first and second embodiments, the detected pressure of the pressure sensor PS (not shown) is kept constant (0.6 MPa in this embodiment) by adjusting the opening of the motor valve 8. Instead, the motor valve 8 is not provided, and the speed of the pump 5 is controlled according to a command from the control unit CONT, thereby detecting the pressure p1 detected by the pressure sensor PS (not shown) and the second pressure sensor PS2 (not shown). It is also possible to keep the differential pressure (= p1-p2) from the detected pressure p2 constant (0.6 MPa in this embodiment). In this case, the piping circuit pressure loss for the working medium can be reduced. In this case, speed control can be easily performed by using a DC brushless motor as the drive motor MT of the pump 5.

  Further, even when an AC motor that is widely used as a drive motor for the pump 5 is used, the drive circuit for the motor M in the control unit CONT is configured by a VVVF (variable voltage, variable frequency) inverter. Excellent speed controllability is obtained, and the differential pressure between the detected pressure p1 of the pressure sensor PS (not shown) and the detected pressure p2 of the second pressure sensor PS2 (not shown) is constant (a value of about 0.6 MPa or more) Can be controlled systematically.

[Another Example 2]
As an embodiment, a system without the battery B is also possible.
In this case, the location of the battery B in the first and second embodiments is simply a DC link LN, and can be supplied to the link from the external commercial power system EXPW instead of the external power supply inverter INV2, and the DC link. By providing a power conditioner PWCN capable of reverse power flow from the LN to the external commercial power system EXPW, a system that can be used without any problem even when there is a difference between the power obtained in this system and the power consumption outside this system It becomes.

  It is also possible to install the battery B in parallel with the DC link LN and to supply power from the battery B to the external power supply inverter INV2. In this case, a power failure occurred in the external commercial power system EXPW. Even in this case, power supply can be continued stably from the external power supply inverter INV2.

[Another Example 3]
A refrigerant other than CO2 may be used.

[Another Example 4]
Further, the working medium is not limited to butane, and the working medium is composed of a single organic compound or a mixture of a plurality of different types of organic compounds, whereby the working medium is guided from the working medium heat exchanger 3 to the screw turbine 6. The ratio of vapor and gas contained in the medium can be changed, and the working medium can be changed as appropriate.

[Another Example 5]
In FIG. 1, the pump 5 is replaced with a working medium compressor whose output can be variably controlled, and the discharge of the screw turbine is discharged so that the gas containing the liquid phase is discharged from the discharge port (discharge port) of the screw turbine. It is also possible to set the operating conditions so that the pressure at the outlet (exhaust port) (the detected pressure p2 in the second pressure sensor PS2 (not shown) described above) becomes low.

  In this case, although the efficiency in the working medium cycle is reduced, the condenser 7 is not necessary, and the piping is simplified as the condenser 7 is unnecessary, and a mixture of a plurality of hydrocarbons or the like is used as the working medium. Even when it is difficult to make the working medium liquid, the working medium compressor can reliably deliver the working medium.

[Another Example 6]
In the first embodiment, an example in which the working medium is butane and the turbine 6 is a scroll turbine has been described. However, the turbine 6 may be changed to a screw turbine as appropriate.

Furthermore, the working medium and the turbine 6 can be appropriately selected, such as using another type of capacity turbine as the turbine 6.

[Another Example 7]
In the first embodiment and the second embodiment, the power generated by the generator G is supplied as power consumed by the power generation system (total power) for the compressor 2, the pump 5, the control unit CONT, and the like. However, you may supply the electric power consumed by this power generation system for compressor 2, pump 5, control part CONT, etc. from this power generation system outside.

  In each of the above embodiments, when a blower that promotes heat exchange between the outside air A and the working medium in the outside air heat exchanger 1 is provided, rather than an increase in power consumption (total power) accompanying the operation of the blower, When the increase in the generated power accompanying the increase in the COP of the heat pump due to the heat exchange is increased, the true generated power Wz is increased. Therefore, in order to configure an efficient power generation system, the above-described blower is provided. It goes without saying that the blower is operated appropriately.

1 External air heat exchanger 2 Compressor 3 Working medium heat exchanger 4 Expansion valve 5 Pump (circulation means)
6 Turbine (scroll turbine)
7 Condenser (cooling part)
8 Motor valve A Outside air B Battery CH Check valve CONT Control unit LN DC link EXPW External commercial power system G Generator H Auxiliary heat source INV1 Compressor inverter INV2 External power supply inverter PS Pressure sensor PS2 Second pressure sensor R Regulator TH Temperature detector

Claims (5)

An outside air heat exchanger that includes a refrigerant heating channel, absorbs heat from outside the system, transmits the heat to the refrigerant flowing through the refrigerant heating channel, and vaporizes the refrigerant, and a compressor that compresses the refrigerant from the outlet of the refrigerant heating channel A working medium heat exchanger that heats the working medium with the compressed refrigerant, and a refrigerant heating flow of the outside air heat exchanger that collects the refrigerant discharged from the working medium heat exchanger after the working medium is heated. A recovery path that leads to the inlet of the path, and constitutes a heat pump comprising the outside air heat exchanger, the compressor, the refrigerant flow path of the working medium heat exchanger, the recovery path, and the refrigerant,
And a turbine having an inlet and an outlet, wherein the working medium flowing through the working medium flow path of the working medium heat exchanger is vaporized by heating by the heat pump, and after being vaporized, the outlet of the working medium flow path The working medium discharged from the inlet is introduced into the inlet and discharged from the outlet, so that the turbine is powered by the heat energy of the vaporized working medium, and power is generated by the power. An operation system comprising a circulation means for delivering the working medium discharged from the discharge port to an inlet of the working medium flow path, and comprising the working medium flow path, the turbine, the circulation means, and the generator. Configure the medium power generation cycle section,
A control unit for controlling the heat pump and the working medium power generation cycle unit;
Compressor driving power for driving the compressor, circulating means driving power for driving the circulating means, and power as control section power supplied to the control section are supplied,
True generated power that is an operating condition that is set such that the generated power generated by the generator is larger than the total power that is the sum of the compressor driving power, the circulation means driving power, and the control unit power A power generation system configured to operate under acquisition conditions,
An organic compound whose saturated vapor pressure at 90 ° C. is 0.3 MPa or more is used as the working medium, the refrigerant is CO2, and the turbine is a scroll turbine or a screw turbine.
The true generated power acquisition condition is that the inlet temperature, which is the temperature of the working medium at the inlet, is approximately 90 ° C., and the inlet pressure, which is the pressure of the working medium, at the inlet is the inlet temperature. The power generation system is set to operating conditions that are equal to or lower than a saturated vapor pressure of the working medium. The power generation system according to claim 1, further comprising an auxiliary heat source for heating the working medium before being introduced into the introduction port. The power generation system according to claim 2, wherein the refrigerant flowing through the recovery path is heated by exhaust heat remaining after the working medium is heated before the auxiliary heat source is introduced into the introduction port.   The refrigerant | coolant which cools the said working medium discharged | emitted from the said discharge port with the said refrigerant | coolant after the refrigerant | coolant which flows through the said collection | recovery path | route absorbs the heat from the outside of a system with the said external air heat exchanger is provided. Item 1. The power generation system according to items 1 to 3.   The power generation system according to claim 1, further comprising a check valve that prevents a backflow of the working medium from the working medium flow path to the circulation unit.

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