JP2007057141A - Refrigeration cycle equipment - Google Patents

Abstract

A high-pressure side refrigerant pressure of a refrigeration cycle apparatus is controlled to operate efficiently.
A refrigeration cycle apparatus 12 is driven by a refrigeration cycle 5 that sequentially connects a compressor 1, a radiator 2, an expander 6a that converts pressure energy of refrigerant into rotational power, and an evaporator 4, and an expander 6a. The generator 6b that converts the rotational power into electric power, the secondary battery 8 that stores the electric power converted by the generator 6b via the switching mechanism 9, and the refrigerant that measures the state of the refrigerant circulating in the refrigeration cycle 5 A state measuring unit 10 and a control unit 11 for controlling the switching mechanism 9 based on the output of the refrigerant state measuring unit 10 are provided, and the number of secondary batteries 8 to be stored is increased or decreased by the control of the switching mechanism 9 by the control unit 11. Therefore, the drive frequency of the expander 6a connected to the generator 6b is adjusted to efficiently control the high-pressure side refrigerant pressure at a low cost.
[Selection] Figure 1

Description

  The present invention relates to a refrigeration cycle apparatus, and more particularly to a refrigeration cycle apparatus provided with energy recovery means for recovering expansion energy when a refrigerant expands.

As a conventional refrigeration cycle apparatus, as shown in FIG. 5, there is a refrigeration cycle apparatus that encloses and circulates a refrigerant in a refrigeration cycle 5 in which a compressor 1, a radiator 2, an expansion mechanism 3, and an evaporator 4 are connected in order. Are known. In a refrigeration cycle apparatus using chlorofluorocarbon or alternative chlorofluorocarbon as a refrigerant, an expansion valve, a capillary tube, or the like is used as the expansion mechanism 3. On the other hand, when the difference between the high-pressure side refrigerant pressure and the low-pressure side refrigerant pressure of the refrigeration cycle apparatus is large, the recoverable expansion energy is relatively large. Therefore, as shown in FIGS. A technique for improving the efficiency by recovering the expansion energy using the expander 130 has been proposed.
And as a structure of an expander, as shown in FIG. 6, the system which transmits the motive power collect | recovered with the expander 130 to the compressor 1 with a shaft (not shown), and reduces the input of the compressor 1, As shown in FIG. 7, the power recovered by the expander 130 is converted into electric power by the generator 300 and stored in a secondary battery (not shown), which is input to the compressor 1, the radiator 2, and the evaporator 4. There is a method of assisting the power of the provided fan.
In the refrigeration cycle apparatus as described above, when a refrigerant (for example, carbon dioxide) in which the high-pressure side refrigerant pressure at which the radiator 2 is located exceeds the critical pressure is used, the refrigeration cycle is performed according to the operating conditions of the refrigeration cycle apparatus. Since the theoretical optimum high pressure at which the cooling efficiency or heating efficiency of the apparatus is theoretically best fluctuates, a means for controlling the high-pressure side refrigerant pressure is required. Means for controlling the high-pressure side refrigerant pressure include the following.
In the method of transmitting power with the shaft shown in FIG. 6, the compressor 1 and the expander 130 whose suction volume is generally determined at the time of design are connected by the shaft and driven at the same drive rotational speed f. In this case, the balance of the refrigerant mass sucked per unit time of the compressor 1 and the expander 130 can be expressed by (Expression 1). Here, Vc is the suction volume of the compressor 1, Ve is the suction volume of the expander 130, fc is the drive rotational speed of the compressor 1, fe is the drive rotational speed of the expander 130, and ρc is the compressor 1 Ρe means the refrigerant density before suction of the expander 130, respectively.

  Here, since fc and fe have the same value, ρc and ρe in (Expression 1) have a relationship of (Expression 2) depending on Vc and Ve at the time of design.

That is, if the density ρc of the refrigerant sucked by the compressor 1 is determined from the refrigerant evaporating pressure Peva determined from the heat source temperature TL on the evaporator 4 side or the suction refrigerant temperature Tc of the compressor 1, the refrigerant sucked by the expander 130 The density ρe is fixed at ρc × Vc / Ve. Therefore, the high-pressure side refrigerant pressure is automatically determined by the intake refrigerant temperature Te of the expander 130 depending on the heat source temperature TH on the radiator 2 side and cannot be controlled to the optimum high pressure, or the high-pressure side refrigerant pressure is made the optimum high pressure. In order to match, the heat dissipation capability of the radiator 2 is reduced and the intake refrigerant temperature Te of the expander 130 rises (the intake refrigerant temperature Te of the expander 130 is made higher than the heat source temperature Tg on the radiator 2 side). Can not be adjusted downward).
When the high-pressure side refrigerant pressure cannot be freely adjusted, the cooling efficiency or heating efficiency of the refrigeration cycle apparatus deteriorates. When the intake refrigerant temperature Te of the expander 130 is increased, the heat dissipation amount of the radiator 2 and the evaporator Therefore, the cooling efficiency or heating efficiency of the refrigeration cycle apparatus is similarly deteriorated.
Therefore, as shown in FIG. 6, the suction volume Ve of the expander 130 is designed according to the condition that the suction refrigerant density ρe is the highest, and it can pass through the expander 130 under the condition that the suction refrigerant density ρe becomes small. A method in which an electronic control unit (ECU) 400 controls an opening degree of a control valve 180 provided in the bypass passage 170 based on detection signals from the pressure sensor 401 and the temperature sensor 402. (For example, refer to Patent Document 1).
Further, in the case of a system in which power is converted into electric power by the generator 300 shown in FIG. 7, the ECU 400 controls the applied voltage (excitation current) of the generator 300 based on detection signals from both the sensors 401 and 402. That is, as shown in FIG. 8, an excitation current is supplied from the control circuit 310 to the rotor coil 303b of the rotor of the generator 300 via a brush and a slip ring, and the generator 300 and the expander 130 are controlled by controlling the excitation current. Control the number of revolutions. As described above, there is a method of controlling the high-pressure side refrigerant pressure of the refrigeration cycle apparatus without restrictions on the suction refrigerant density ρe of the expander 130 (see, for example, Patent Document 1 or Patent Document 2).
In addition, there is a method of using a thyristor inverter (not shown) for controlling the rotational speed of the generator driven by the expander (see, for example, Patent Document 3).
Further, since the compressor efficiency of the compressor 1 changes according to the operating conditions of the refrigeration cycle apparatus, in order to maximize the cooling efficiency or the heating efficiency, the fluctuation of the compressor efficiency due to the operating conditions of the refrigeration cycle apparatus is taken into consideration. Therefore, it is necessary to derive the optimum high pressure (see, for example, Patent Document 4).
JP 2000-329416 A JP-A-1-168518 JP 60-42557 A JP 2004-53150 A

However, in a refrigeration cycle apparatus having an expander that is connected to a compressor and a shaft to recover power, the refrigerant flows through a bypass passage provided in parallel with the expander in order to control the refrigerant pressure at a high pressure side. The recovery power was reduced by bypassing the refrigerant with energy.
Further, in the refrigeration cycle apparatus that recovers power by the generator, the high-pressure side refrigerant pressure is controlled by controlling the rotational speed of the generator and the expander by the excitation current that is supplied to the rotor coil. There was a loss of power.
In addition, the thyristor inverter that controls the rotational speeds of the generator and the expander has a complicated circuit and is expensive, which increases the manufacturing cost of the refrigeration cycle apparatus. Further, in order to improve the performance of the refrigeration cycle apparatus using the expander, the optimum high pressure cannot be calculated unless the efficiency of the expander is further taken into consideration in addition to the efficiency of the compressor.
In addition, energy-generating devices such as solar cells and wind power generators have been widely used to prevent global warming, but the attached power storage devices have been fully utilized for applications other than solar cells and wind power generators. There wasn't.

  Therefore, the present invention is to solve the above-mentioned problem, and is to provide a supercritical refrigeration cycle apparatus using an expander, which can control the high-pressure side refrigerant pressure at low cost. It is aimed.

A refrigeration cycle apparatus according to a first aspect of the present invention is produced by a compressor, a radiator, an expander that converts pressure energy of a passing refrigerant into rotational power, and a refrigeration cycle that sequentially connects an evaporator and an expander. A rectifier having a generator that converts the rotating power into electric power, an AC side terminal that is connected to the output terminal of the generator, and a DC side terminal that outputs the rectified power, and parallel to the DC side terminal of the rectifier Measures the state of the refrigerant circulating in the refrigeration cycle, the secondary battery composed of at least two connected to the battery, the switching mechanism for switching connection / disconnection between the DC terminal and the secondary battery individually And a control means for calculating the optimum high pressure on the radiator side based on the output of the refrigerant condition measuring means and controlling the switching mechanism so that the refrigerant pressure on the radiator side matches the optimum high pressure. Is.
According to the first invention, the output terminal of the generator that converts the power recovered by the expander into electric power,
By connecting multiple secondary batteries in parallel through a rectifier and increasing or decreasing the number of connected secondary batteries with a switching mechanism, the load on the generator can be adjusted to control the drive frequency of the expander connected to the generator . Accordingly, the volume circulation amount of the refrigerant passing through the expander can be made variable, and the density and pressure of the refrigerant sucked into the expander can be made variable. In other words, by adjusting the rotation speed of the expander without using a bypass or the like, the refrigerant pressure on the radiator side can be adjusted to the optimum high pressure calculated based on the refrigerant state measuring means. The refrigeration cycle apparatus can be operated. Furthermore, the refrigerant state measuring means can detect the temperature of the refrigerant sucked by the expander and the refrigerant pressure before and after the expander, and the density, enthalpy and entropy of the refrigerant sucked by the expander can be calculated. This makes it possible to calculate the theoretical recovery power when the expander has an ideal adiabatic expansion, and calculates the expander efficiency of the expander from the generated power of the generator in consideration of the generator efficiency of the generator. can do. Therefore, the refrigeration cycle apparatus can be more efficiently operated by adding the expander efficiency of the expander to the calculation method of the optimum high pressure in consideration of the compressor efficiency of the conventional compressor. In addition, by storing the recovered power in the secondary battery as electric power, the refrigeration cycle device is operated by cheap night electric power, and the power recovered by the expander during the daytime when the power demand is large and the power unit price is high is used as electric power. As a result, running costs can be kept low. For this reason, even if the power generation loss caused by the generator is taken into consideration, the refrigeration cycle of the present invention is more effective than the case where the compressor and the expander are connected by a single shaft and the power recovered by the expander is directly used for assisting the compressor. The cost merit for the user of the device is increased.
A refrigeration cycle apparatus according to a second invention is the refrigeration cycle apparatus according to the first invention, comprising a secondary battery and a switching mechanism as an external power storage device.
According to the second invention, the refrigeration cycle apparatus can be manufactured at low cost by commonly using the external power storage device included in the solar battery, the wind power generator, and the like.
A refrigeration cycle apparatus according to a third aspect of the present invention is the refrigeration cycle apparatus according to the first or second aspect of the invention, further comprising a power storage detection means for detecting a power storage state of the secondary battery, and the control means uses the output of the power storage detection means. To control the switching mechanism.
According to the third invention, when the control means determines the combination of the plurality of secondary batteries connected to the generator by detecting the difference in the storage status, the load on the generator is smoothed instead of stepwise. Can be varied. As a result, when the operating conditions of the refrigeration cycle apparatus fluctuate, the rotational speed of the expander can be continuously changed to cope with it, so that sudden fluctuations such as pressure can be avoided. In addition, the refrigerant pressure on the radiator side of the refrigeration cycle can be accurately matched to the optimum high pressure.
A refrigeration cycle apparatus according to a fourth aspect of the invention is the refrigeration cycle apparatus according to the third aspect of the invention, wherein current measurement means for measuring a current flowing through each secondary battery is used as the power storage detection means.
According to the fourth invention, since the electromotive force of the secondary battery varies depending on the storage state and the voltage applied to the terminals of the secondary battery connected in parallel to the generator is equal, the current passing through each secondary battery is measured. By doing so, the storage state of each secondary battery can be easily estimated.
A refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to the first to fourth aspects, wherein a power conditioner is provided between the secondary battery and the commercial power source.
According to the fifth aspect of the invention, the electric power stored in the secondary battery by the power recovery by the expander of the refrigeration cycle apparatus can be used in general electric equipment together with the commercial power source.
A refrigeration cycle apparatus according to a sixth aspect of the present invention is the refrigeration cycle apparatus according to the first to fifth aspects of the present invention, wherein a refrigerant mainly composed of carbon dioxide is used as the refrigerant.
According to the sixth invention, when the operating state of the refrigeration cycle apparatus is changed by using, as a refrigerant, carbon dioxide that becomes supercritical when the refrigerant pressure on the radiator side exceeds the critical pressure in general applications. There is an optimum high pressure for the refrigerant pressure on the radiator side. Thereby, when this invention is used, a refrigerating-cycle apparatus can be operated efficiently.
The refrigeration cycle apparatus according to a seventh aspect of the invention is the refrigeration cycle apparatus according to the first or second aspect of the invention, wherein the refrigerant state measuring means detects the refrigerant temperature sucked by the expander and the refrigerant pressure before and after the expander, and the control means Then, the expander efficiency is calculated from the suction refrigerant temperature and the front and rear refrigerant pressure, and the optimum high pressure is calculated in consideration of the expander efficiency.
According to the seventh invention, the refrigeration cycle apparatus can be operated more efficiently by adding the expander efficiency to the conventional calculation method of the optimum high pressure in consideration of the compressor efficiency.

  According to the present invention, a plurality of secondary batteries are connected in parallel through a rectifier to an output terminal of a generator that converts power recovered by an expander into electric power, and the number of connected secondary batteries is increased or decreased by a switching mechanism. By adjusting the load of the generator, the drive frequency of the expander connected to the generator can be controlled. Accordingly, the volume circulation amount of the refrigerant passing through the expander can be made variable, and the density and pressure of the refrigerant sucked into the expander can be made variable. That is, since the rotation speed of the expander can be adjusted so that the refrigerant pressure on the radiator side matches the optimum high pressure calculated based on the refrigerant state measuring means, the refrigeration cycle apparatus can be operated efficiently. . In addition, by storing the recovered power in the secondary battery as electric power, the refrigeration cycle device is operated by cheap night electric power, and the power recovered by the expander during the daytime when the power demand is large and the power unit price is high is used as electric power. As a result, running costs can be kept low.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention.
The refrigeration cycle apparatus 12 of the present embodiment includes a refrigeration cycle 5 that sequentially connects an expander 6a and an evaporator 4 that convert the pressure energy of refrigerant that passes through the compressor 1 and the radiator 2 into rotational power, and an expander. 6a and a power recovery mechanism 6 including a generator 6b that converts rotational power generated in the expander 6a into electric power, an AC side terminal 7a connected to the output terminal 6ba of the generator 6b, and output rectified power A rectifier 7 having a DC side terminal 7b, a secondary battery 8 composed of at least two connected in parallel to the DC side terminal 7b of the rectifier 7, a DC side terminal 7b and a secondary battery. 8, a switching mechanism 9 that individually switches between connection / disconnection between them, refrigerant state measurement means 10 that measures the state of the refrigerant circulating in the refrigeration cycle 5, and output of the refrigerant state measurement means 10 Based on heatsink 2 Has an optimum high pressure is calculated, and control means 11 for controlling the switching mechanism 9 so as to adjust the pressure of the refrigerant in the radiator 2 side to the optimal high pressure.

Next, the operation of the refrigeration cycle apparatus 12 will be described.
In the refrigeration cycle apparatus 12, the refrigerant circulates in the direction indicated by the arrow. The refrigerant carbon dioxide in the gas phase is compressed in the compressor 1 to a supercritical state of high temperature and high pressure that exceeds the critical point, and is sent to the radiator 2. The high-temperature and high-pressure refrigerant in the supercritical state decreases in temperature while radiating heat while maintaining the pressure in the radiator 2. The high-pressure refrigerant that has exited the radiator 2 enters the power recovery mechanism 6 and performs expansion work in the power recovery mechanism 6 to generate electric power.
Specifically, the expander 6a of the power recovery mechanism 6 converts the volume change due to the expansion of the refrigerant into rotational power, and electric power is generated by the generator 6b connected to the expander 6a by a shaft. Specific examples of the expander 6a include a scroll expander, a vane rotary expander, a rotary expander, and a two-stage rotary expander.
Then, the refrigerant decompressed by the expander 6a is guided to the evaporator 4 to evaporate, and is again sucked into the compressor 1.

On the other hand, the electric power generated in the generator 6b is supplied from the output terminal 6ba of the generator 6b to the rectifier 7 through the AC side terminal 7a of the rectifier 7, and is converted into direct current by the rectifier 7. Then, it is stored in a plurality of secondary batteries 8 connected in parallel to the DC side terminal 7 b of the rectifier 7.
These secondary batteries 8 are connected to the DC side terminal 7b of the rectifier 7 so as to be individually switchable / unconnected by the switching mechanism 9, and the number of parallel connections of the secondary batteries 8 to the generator 6b is increased. Then, since the electric resistance of the circuit composed of the secondary battery 8 is reduced, the current flowing due to the electromotive force of the generator 6b increases. Here, if the power recovered by the expander 6a does not increase or decrease, the braking force due to the increase in the current flowing through the generator 6b increases and the drive rotational speed of the generator 6b and the expander 6a decreases.
Conversely, when the number of parallel connections of the secondary battery 8 to the generator 6b is reduced, the electrical resistance of the circuit formed by the secondary battery 8 increases, and thus the current flowing due to the electromotive force of the generator 6b decreases. Here, if the power recovered by the expander 6a does not increase or decrease, the braking force due to the decrease in the current flowing through the generator 6b decreases, and the drive rotational speed of the generator 6b and the expander 6a increases.
The control mechanism 11 controls the switching mechanism 9 so that the refrigerant pressure on the radiator 2 side is adjusted to the optimum high pressure based on the output of the refrigerant state measuring means 10 that measures the state of the refrigerant circulating in the refrigeration cycle 5. .

  In the refrigeration cycle apparatus 12 of the present embodiment as described above, a plurality of secondary batteries 8 are connected in parallel through the rectifier 7 to the output terminal 6ba of the generator 6b that converts the power recovered by the expander 6a into electric power. The drive frequency of the expander 6a connected to the generator 6b can be controlled by adjusting the load of the generator 6b by increasing or decreasing the number of the secondary batteries 8 to be connected by the switching mechanism 9. Thereby, the volume circulation amount of the refrigerant passing through the expander 6a can be made variable, and the density and pressure of the refrigerant sucked into the expander 6a can be made variable. That is, by adjusting the rotation speed of the expander 6a without using a means such as a bypass, it becomes possible to match the refrigerant pressure on the radiator 2 side with the optimum high pressure calculated based on the refrigerant state measuring means 10, The refrigeration cycle apparatus 12 can be operated efficiently. That is, it is possible to efficiently control the high-pressure side refrigerant pressure without reducing the recovery power by bypassing the refrigerant or losing power by energizing the rotor coil.

Further, since the refrigerant state measuring means 10 of the present embodiment can detect the temperature of the refrigerant sucked by the expander 6a and the refrigerant pressure before and after the expander 6a, the density and enthalpy of the refrigerant sucked by the expander 6a. And entropy can be calculated. As a result, the theoretically recovered power when the expander 6a has undergone ideal adiabatic expansion can be calculated, and the expansion efficiency of the expander 6a can be calculated from the generated power of the generator 6b in consideration of the generator efficiency of the generator 6b. The efficiency can be calculated. With this configuration, the refrigeration cycle apparatus 12 can be operated more efficiently by adding the expander efficiency of the expander 6a to the calculation method of the optimum high pressure in consideration of the compressor efficiency of the conventional compressor 1. .
Further, by storing the recovered power as electric power in the secondary battery 8, the electric power stored in the secondary battery 8 during the daytime when the refrigeration cycle apparatus 12 is operated by cheap nighttime electric power and the electric power demand is large and the electric power unit price is high. Running costs can be kept low. For this reason, even when taking into consideration the power generation loss that occurs in the generator 6b, the compressor 1 and the expander 6a are connected by a single shaft and the power recovered by the expander 6a is used directly for assisting the compressor 1, The merit of the user of the refrigeration cycle apparatus 12 of the present embodiment is increased.
(Embodiment 2)

FIG. 2 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 2 of the present invention.
The refrigeration cycle apparatus 112 according to the present embodiment includes a compressor 1, a radiator 2, a refrigeration cycle 5 that sequentially connects an expander 6 a that converts pressure energy of refrigerant passing therethrough to rotational power, and an evaporator 4, and an expander. 6a and a power recovery mechanism 6 composed of a generator 6b that converts the rotational power generated in the expander 6a into electric power, an AC side terminal 107a connected to the output terminal 6ba of the generator 6b, and output rectified power A rectifier 107 having a DC side terminal 107b to be connected, and at least two or more secondary batteries 108 connected in parallel to the DC side terminal 107b of the rectifier 107 and connection / individual secondary battery 108 An external power storage device 120 having a switching mechanism 109 for individually switching non-connection, refrigerant state measuring means 10 for measuring the state of refrigerant circulating in the refrigeration cycle 5, and refrigerant state measuring means 1 Of calculating the optimal high pressure of the radiator 2 side based on the output, and a control unit 111 for controlling the switching mechanism 109 so as to match the pressure of the refrigerant in the radiator 2 side to the optimal high pressure.
That is, in the refrigeration cycle apparatus 112 of the present embodiment, compared to the refrigeration cycle apparatus 12 of the first embodiment, the power generated by the generator 6b is recharged via the DC side terminal 107b of the rectifier 107. 108 and the external power storage device 120 having the switching mechanism 109 are different. Since the basic operation is the same as that of the first embodiment, the description thereof is omitted.

In the refrigeration cycle apparatus 112 of the present embodiment as described above, since the external power storage device 120 is an independent device, in addition to the effects of the first embodiment, A household power storage device (secondary battery) provided with a wind power generator and the like and an external power storage device 120 (secondary battery) can be used in common, and the refrigeration cycle device 112 can be manufactured at low cost. .
The introduction of the external power storage device 120 to the home power storage device uses the power generated by the solar battery at the time of failure of the power infrastructure due to a disaster at night, or the power generated by the wind power generator at night is high in unit price of power The purpose is to store electricity for daytime use. In addition, inexpensive nighttime power can be purchased from an electric power company, stored in the external power storage device 120, and used in the daytime. Among these, when the external power storage device 120 is used in preparation for a disaster, a comprehensive cost merit can be obtained by effectively using the external power storage device 120 with the refrigeration cycle device 112 except during a disaster.
(Embodiment 3)

FIG. 3 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 3 of the present invention.
Compared with the refrigeration cycle apparatus 12 of the first embodiment, the refrigeration cycle apparatus 212 of the present embodiment includes the power storage detection means 221 that detects the power storage state of each secondary battery 8, and the control means 211 detects the power storage. The difference is that the switching mechanism 9 is controlled using the output of the means 221.
Next, the operation of the refrigeration cycle apparatus 212 will be described. Since the basic operation of the refrigeration cycle apparatus 212 is the same as that of the refrigeration cycle apparatus 12 of the first embodiment, the different parts will be described.
The control means 211 of the refrigeration cycle apparatus 212 uses the switching means 9 so that the load on the generator 6b does not change abruptly based on the output of the power storage detection means 221 that detects the power storage state of each secondary battery 8. Then, the secondary battery 8 is selectively connected to the generator 6b. This utilizes the fact that the terminal voltage of each secondary battery 8 changes due to the difference in the storage state and the electrical resistance differs. That is, in order to smoothly change the current flowing through the generator 6b, the optimum connection combination of the secondary batteries 8 is derived from the storage state of the individual secondary batteries 8.

In the refrigeration cycle apparatus 212 of the present embodiment as described above, in addition to the effects of the first embodiment, the power storage detector 221 detects the difference in the power storage status of the secondary battery 8 to connect to the generator 6b. When the control unit 211 determines the combination of the plurality of secondary batteries 8 to be performed, the load on the generator 6b can be smoothly changed instead of stepwise. As a result, when the operating condition of the refrigeration cycle apparatus 212 fluctuates, the rotation speed of the expander 6a can be continuously changed to cope with it, so that sudden fluctuations such as pressure can be avoided.
Further, since the volume circulation amount of the refrigerant passing through the expander 6a can be smoothly changed instead of stepwise, the refrigerant pressure on the radiator 2 side of the refrigeration cycle apparatus 212 can be accurately matched to the optimum high pressure. it can.
In addition, the structure using the current measurement means (for example, general ammeter) which measures each electric current which flows through the secondary battery 8 as the electrical storage detection means 221 may be sufficient. In such a configuration, the electromotive force of the secondary battery 8 varies depending on the storage state, and the voltage applied to the terminal of the secondary battery 8 connected in parallel to the generator 6b is equal. By measuring the current to be performed, the storage state of each secondary battery 8 can be easily estimated.
(Embodiment 4)

FIG. 4 is a configuration diagram of a refrigeration cycle apparatus according to Embodiment 4 of the present invention.
The refrigeration cycle apparatus 312 according to the present embodiment includes a power conditioner 322 between the secondary battery 8 and the commercial power supply 323, as compared with the refrigeration cycle apparatus 212 according to the third embodiment. That is, the point that the electric power stored in the secondary battery 8 is connected to the commercial power source 323 via the power conditioner 322 is different. Since the basic operation is the same as that of the first embodiment, the description thereof is omitted.
In the refrigeration cycle apparatus 312 of the present embodiment as described above, in addition to the effects of the third embodiment, electric power stored in the secondary battery 8 by power recovery by the power recovery mechanism 6 of the refrigeration cycle apparatus 312 is used as a commercial power source. It can be used with general electrical equipment together with H.323. That is, since the power can be used not only in a device that can directly use the DC power supply of the secondary battery 8 but also in a wide range of electrical devices, the power of the secondary battery 8 can be easily used.

In addition, although the effect of Embodiment 1-Embodiment 4 arises irrespective of the kind of refrigerant | coolant, when carbon dioxide is used as a refrigerant | coolant, it works more effectively.
That is, in the case of a refrigeration cycle apparatus using a refrigerant mainly composed of carbon dioxide, the pressure of the refrigerant discharged from the compression mechanism section exceeds the critical pressure, so that no phase change occurs in the cooling process in the radiator. In other words, because it shows excellent characteristics when used for heating applications, it is easy to use in heat pump water heaters and heat storage heaters that use nighttime power, and the power collected at night by the expander is stored in the secondary battery as power. It is suitable for the refrigeration cycle apparatus according to Embodiments 1 to 4 that uses electric power in the daytime. Further, there is an advantage that carbon dioxide can be used as an environmentally friendly refrigerant having an ozone depletion coefficient of 0 and a global warming coefficient of 1 and having no flammability and toxicity.

  The refrigeration cycle apparatus of the present invention can easily control the high-pressure side refrigerant pressure of the refrigeration cycle apparatus and efficiently operate the refrigeration cycle apparatus, and thus can be applied to uses such as an air conditioner, a water heater, and a refrigerator.

Configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. The block diagram of the refrigerating-cycle apparatus of Embodiment 2 of this invention Configuration diagram of refrigeration cycle apparatus according to Embodiment 3 of the present invention Configuration diagram of a refrigeration cycle apparatus according to Embodiment 4 of the present invention. Configuration diagram of conventional refrigeration cycle equipment Configuration diagram of a conventional refrigeration cycle apparatus using a power transmission type expander Configuration diagram of a conventional refrigeration cycle apparatus using a power transmission type expander Excitation circuit diagram of the generator of the refrigeration cycle apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Radiator 3 Expansion mechanism 4 Evaporator 5 Refrigeration cycle 6 Power recovery mechanism 6a Expander 6b Generator 6ba Output terminal 7,107 Rectifier 7a, 107a AC side terminal 7b, 107b DC side terminal 8,108 Secondary battery 9, 109 switching mechanism 10 refrigerant state measuring means 11, 111, 211 control means 12, 112, 212, 312 refrigeration cycle apparatus 120 external power storage device 221 power storage detection means 322 power conditioner 323 commercial power supply

Claims (7)

A refrigeration cycle that sequentially connects a compressor, a radiator, an expander that converts the pressure energy of the refrigerant that passes into rotary power, and an evaporator;
A generator that converts the rotational power generated in the expander into electric power;
A rectifier comprising an AC side terminal connected to the output terminal of the generator and a DC side terminal for outputting rectified power;
A secondary battery composed of at least two connected in parallel to the DC side terminal of the rectifier;
A switching mechanism for individually switching connection / disconnection between the DC side terminal and the secondary battery;
Refrigerant state measuring means for measuring the state of the refrigerant circulating in the refrigeration cycle;
Control means for calculating the optimum high pressure on the radiator side based on the output of the refrigerant state measuring means and controlling the switching mechanism so that the refrigerant pressure on the radiator side matches the optimum high pressure. A characteristic refrigeration cycle apparatus.   The refrigeration cycle apparatus according to claim 1, wherein the secondary battery and the switching mechanism are provided as external power storage devices. A power storage detecting means for detecting a power storage state of the secondary battery;
The refrigeration cycle apparatus according to claim 1 or 2, wherein the control unit controls the switching mechanism using an output of the power storage detection unit.   The refrigeration cycle apparatus according to claim 3, wherein a current measuring unit that measures a current flowing through each of the secondary batteries is used as the power storage detecting unit.   The refrigeration cycle apparatus according to any one of claims 1 to 4, further comprising a power conditioner between the secondary battery and a commercial power source.   The refrigeration cycle apparatus according to any one of claims 1 to 5, wherein a refrigerant mainly composed of carbon dioxide is used as the refrigerant. The refrigerant state measuring means detects the refrigerant temperature sucked by the expander and the refrigerant pressure before and after the expander,
The said control means calculates expander efficiency from the said suction | inhalation refrigerant | coolant temperature and the said front-and-rear refrigerant | coolant pressure, and calculates the said optimal high pressure in consideration of this expander efficiency. Refrigeration cycle equipment.

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