JPH07280367A - Cold thermal storage system - Google Patents

Abstract

PURPOSE:To contrive energy conservation by optimally controlling a refrigerant amount in a cold thermal storage circuit at each operating mode. CONSTITUTION:An output of a saturation temperature sensor 13 is sent as a temperature signal by a saturation temperature detector 15 to a differential temperature calculator 17. An output of a receiver upper temperature sensor 14 provided at an upper part of a receiver 12 is sent as a temperature signal by a temperature detector 16 to the calculator 17. In this case, a differential temperature (= saturation temperature - receiver upper temperature) is calculated and sent together with an operating mode from an operating mode discriminator 19 to a solenoid valve set discriminator 18, which sends a command to solenoid valves 10f, 10g to be controlled. Thus, solenoid valve control means for so controlling as to become less refrigerant amount than that at the time of cold dissipating operation is provided at the time of a cold thermal storage operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold storage system which controls the amount of refrigerant in a secondary side circuit according to an operation mode.

[0002]

2. Description of the Related Art There is a heat storage type cooling system of a water heat storage system or an ice heat storage system for cooling and supplying hot and cold water to a house, a building and the like. This system consists of a refrigerator and a cold water heat storage tank or an ice heat storage tank.In order to adjust the time lag between heat generation and demand, cold water or ice is stored using night power, and this cold heat storage is stored in the daytime. It is intended to save energy by taking it out when necessary and using it for cooling and hot water supply. When comparing the water heat storage method and the ice heat storage method, the ice heat storage method has an advantage that the volume can be significantly reduced as compared with the water heat storage method, and this ice heat storage method has been widely adopted.

The ice heat storage system is roughly classified into two types, a solid ice system and a liquid ice system. The liquid ice method is a method in which a refrigerant and cold water are brought into direct or close contact with each other to form sleet-shaped ice (slurry) and stored in a heat storage tank, but the control is complicated. On the other hand, the solid ice method, which is generally adopted at present, passes a refrigerant or brine through a coil hole provided inside the ice heat storage tank to generate ice on the outer surface of the coil, and the resulting cold heat is used as a cooling load. It supplies and cools.

The conventional ice heat storage system will be described below with reference to the drawings. FIG. 9 is a refrigeration cycle diagram of a heat storage type cooling system (hereinafter referred to as a cool storage system) based on a conventional ice heat storage method (solid ice method).

This cold storage system is composed of a primary side circuit in which the primary side refrigerant circulates and a secondary side circuit in which the secondary side refrigerant circulates.

The primary side circuit includes an inverter-driven variable capacity (frequency) type compressor 1 (hereinafter simply referred to as a compressor), a first
The condenser 2, the electric expansion valve 3 whose pulse opening can be pulse-controlled by using the stepping motor, and the first evaporator 4 are sequentially connected to form a refrigeration cycle.

In the secondary side circuit, a refrigerant pump 5 for delivering a secondary side liquid refrigerant and a cold storage tank 6 are installed, and cold storage heat exchange for absorbing heat from the water in the cold storage tank 6 to generate ice on the surface thereof. Container 7, second condenser 8 used only in cold storage operation for storing ice heat, second evaporator 9 used only in cooling operation in which cold heat is taken out from the produced ice to perform cooling operation, Solenoid valves 10a, 10b that open and close depending on the operation mode
10c, 10d, a bypass circuit 11 that connects the outlet of the cold storage heat exchanger 7 and the refrigerant pump inlet during the cooling operation, and a solenoid valve 10e that is opened only during the cooling operation are provided in the bypass circuit.

The first evaporator on the primary side and the second condenser used only during the cold storage operation on the secondary side are integrated into one refrigerant-refrigerant heat exchanger, where the secondary side is placed. Heat is transferred from the refrigerant to the primary side refrigerant.

During the cold storage operation for storing ice heat, both the primary side circuit and the secondary side circuit are operated. In the secondary side circuit, the secondary side refrigerant having a temperature lower than that of the water in the cold storage tank 6 is delivered from the refrigerant pump 5, passes through the electromagnetic valve 10a and enters the cold storage heat exchanger 7, where it absorbs heat from the water. After being gasified, it passes through the solenoid valve 10b and enters the second condenser 8, where heat is released to the primary side refrigerant, liquefies and returns to the refrigerant pump 5, thereby forming a refrigeration cycle. Then, as the water temperature lowers, the secondary side refrigerant temperature also lowers, and when the temperature becomes lower than zero, ice begins to be generated on the outer surface of the cold storage heat exchanger 7 and gradually grows.

During the cooling operation in which cold heat is taken out from the produced ice to perform the cooling operation, only the secondary side circuit is operated without operating the primary side circuit. In the secondary side circuit, the secondary side liquid refrigerant sent out from the refrigerant pump 5 passes through the solenoid valve 10c to the second side.
After passing through the solenoid valve 10d and entering the cold storage heat exchanger 7 from the opposite direction to the cold storage operation, the cooling operation is performed to remove the heat from the air and gasify it. Also, a refrigeration cycle is formed in which heat is released to water and liquefied, passes through the bypass circuit 11 and the electromagnetic valve 10e, and returns to the refrigerant pump 5.

The opening and closing of the solenoid valve for each mode at this time is shown in Table 1 below.

[0012]

[Table 1]

[0013]

However, the above conventional cold storage system has the following problems.

FIG. 2 shows the system efficiency (= cold storage capacity / compressor input) in the cold storage operation when the amount of the secondary side refrigerant is changed. The compressor operating frequency and the refrigerant pump operating frequency are predetermined. It is fixed to the value. As is clear from the figure, the amount of refrigerant that can be cooled is larger than the amount of the secondary-side refrigerant at which the system efficiency during the cold-storage operation shows a peak. Therefore, when trying to obtain the same cold storage capacity, the compressor input becomes high. On the contrary, if the cooling operation is performed with the secondary side refrigerant amount that shows the peak during the cold storage operation, the refrigerant returning to the front side of the refrigerant pump becomes insufficient and gas bite operation occurs, and eventually the refrigerant cannot be sent as a liquid. Will stop.

That is, although the cold storage heat exchanger is used in both the cold storage operation and the cold discharge operation, in the case of this embodiment, heat is radiated from the secondary side refrigerant used only during the cold storage operation to the primary side refrigerant. Comparing the volume in the second condenser with the volume in the second evaporator used only during the cooling operation, the latter has a larger volume of about 2000 cc than the former. Therefore, when performing the most efficient operation both during cold storage operation and during cold discharge operation, more refrigerant is required during cold discharge operation than during cold storage operation, and the same amount of refrigerant is used during cold discharge operation. When the cold storage operation is performed, there is a problem that the operation at the point of high efficiency deviates from the operation at the point of extremely low efficiency.

In view of the above problems, the cold storage system of the present invention is
To enable efficient operation in any operation without complicating the structure of the refrigeration cycle and without adding or removing the amount of refrigerant for each cold storage operation and cooling operation. It is an object.

[0017]

In order to solve the above problems, a regenerator system of the present invention is configured such that a variable capacity compressor, a first condenser, a pressure reducer, and a first evaporator are sequentially connected to a primary side. A refrigeration cycle of the circuit is configured, and a refrigerant pump, a cold storage heat exchanger, and a second condenser are sequentially connected to configure a refrigeration cycle of a secondary side circuit, and between the refrigerant pump and the cold storage heat exchanger, A first bypass circuit that bypasses between the cold storage heat exchanger and the second condenser is provided, and the first flow path switching means, the second evaporator, and the second bypass circuit are provided on the first bypass circuit. Flow path switching means are sequentially provided to bypass between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger and between the refrigerant pump and the first condenser. A second bypass circuit for connecting the second bypass circuit to the third bypass circuit Flow passage switching means is provided, and fourth flow passage switching means is provided between a branch point of the first bypass circuit on the refrigerant pump side and a branch point of the second bypass circuit on the cold storage heat exchanger side. And a fifth flow path switching means between the branch point of the first bypass circuit on the second condenser side and the second condenser, the refrigerant pump, the fourth flow path. An ice cold storage operation in which a secondary side refrigerant is caused to flow in the order of a path switching means, the cold storage heat exchanger, the fifth flow path switching means, and the second condenser;
The first flow path switching means, the second evaporator, the second flow path switching means, the cold storage heat exchanger, the third
The flow control means switches the ice-cooling utilization operation in which the secondary side refrigerant flows in the order of the flow path switching means by the first to fifth flow path switching means, and the first evaporator on the primary side and the secondary side The second condenser is brought into contact with each other in a heat exchange manner, and a sixth passage is switched between the third passage switching means and a branch point of the second bypass circuit on the second condenser side. Means and a receiver, and a seventh flow path switching means between the second bypass circuit and the receiver, and an operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilizing cooling operation. A receiver upper temperature detecting means for detecting an upper temperature and a saturation temperature detecting means for detecting a saturation temperature of the receiver are provided, and the receiver upper temperature and the saturation temperature are selected from the receiver upper temperature detecting means and the saturation temperature detecting means. With The differential temperature calculating means for calculating the temperature provided,
When the operation mode detected by the operation mode detection means is the ice heat storage operation, first, the operation is performed in the ice heat storage operation operation refrigeration cycle, and the sixth and the sixth and The seventh flow path switching means is switched and controlled to perform the ice heat storage operation.

Further, in another cold storage system of the present invention, a variable capacity compressor, a first condenser, a pressure reducer, and a first evaporator are sequentially connected to constitute a refrigeration cycle of a primary side circuit, and a refrigerant is used. A pump, a cold storage heat exchanger, and a second condenser are sequentially connected to form a refrigeration cycle of a secondary side circuit, between the refrigerant pump and the cold storage heat exchanger, and between the cold storage heat exchanger and the second A first bypass circuit for bypassing between the condensers, and a first flow path switching means, a second evaporator, and a second flow path switching means are sequentially provided on the first bypass circuit, A second bypass circuit that bypasses between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger and between the refrigerant pump and the first condenser is provided, A third flow path switching means is provided on the second bypass circuit, and A fourth flow path switching means is provided between a branch point of the first bypass circuit on the medium pump side and a branch point of the second bypass circuit on the cold storage heat exchanger side, and the second condensing unit is provided. A fifth flow path switching means is provided between a branch point of the first bypass circuit on the side of the container and the second condenser, and the refrigerant pump, the fourth flow path switching means, and the cold storage heat exchange are provided. Ice storage operation in which a secondary side refrigerant is caused to flow in the order of a container, the fifth flow path switching means, and the second condenser, the refrigerant pump, and the first flow path switching means,
The second cold evaporator, the second flow path switching means, the cold storage heat exchanger, and the third flow path switching means, in order, the ice cold storage utilization operation in which the secondary-side refrigerant flows Switching control is performed by the flow path switching means of No. 5, and the first evaporator on the primary side and the second condenser on the secondary side are brought into heat exchange contact with each other, and the third flow path switching means and the third flow path switching means are connected. 6th between the branch point of the second bypass circuit on the condenser side of 2nd
The flow path switching means and the receiver are provided, and the seventh flow path switching means is provided between the second bypass circuit and the receiver, and the operation mode detection means for detecting the ice heat storage operation or the ice heat storage utilizing cooling operation is provided. A receiver upper temperature detecting means for detecting the receiver upper temperature and a saturation temperature detecting means for detecting a saturated temperature of the receiver are provided, and the receiver upper temperature detecting means and the receiver upper temperature are provided. Temperature difference calculating means for calculating a temperature difference between the saturation temperature and the saturation temperature, when the operation mode detected by the operation mode detecting means is ice heat storage operation, the operation of the primary circuit and the ice of the secondary circuit Operation in a heat storage utilization refrigeration cycle, and switching control of the sixth and seventh flow path switching means is carried out in accordance with the temperature difference calculated by the temperature difference calculation means, thereby storing ice heat. And performs rolling.

Further, in another regenerator system of the present invention, a variable capacity compressor, a first condenser, a pressure reducer and a first evaporator are sequentially connected to constitute a refrigeration cycle of a primary side circuit, and a refrigerant is used. A pump, a cold storage heat exchanger, and a second condenser are sequentially connected to form a refrigeration cycle of a secondary side circuit, between the refrigerant pump and the cold storage heat exchanger, and between the cold storage heat exchanger and the second A first bypass circuit for bypassing between the condensers, and a first flow path switching means, a second evaporator, and a second flow path switching means are sequentially provided on the first bypass circuit, A second bypass circuit that bypasses between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger and between the refrigerant pump and the first condenser is provided, A third flow path switching means is provided on the second bypass circuit, and A fourth flow path switching means is provided between a branch point of the first bypass circuit on the medium pump side and a branch point of the second bypass circuit on the cold storage heat exchanger side, and the second condensing unit is provided. A fifth flow path switching means is provided between a branch point of the first bypass circuit on the side of the container and the second condenser, and the refrigerant pump, the fourth flow path switching means, and the cold storage heat exchange are provided. Ice storage operation in which a secondary side refrigerant is caused to flow in the order of a container, the fifth flow path switching means, and the second condenser, the refrigerant pump, and the first flow path switching means,
The second cold evaporator, the second flow path switching means, the cold storage heat exchanger, and the third flow path switching means, in order, the ice cold storage utilization operation in which the secondary-side refrigerant flows Switching control is performed by the flow path switching means of 5, and the first evaporator on the primary side and the second condenser on the secondary side are brought into contact with each other in a heat exchange manner to determine whether the ice heat storage operation or the ice heat storage utilization cooling operation is performed. A second evaporator outlet temperature detecting means for detecting an outlet temperature of the second evaporator and a saturation temperature detecting for detecting a saturation temperature of the second evaporator outlet are provided with an operation mode detecting means for detecting. And means for calculating the temperature difference between the second evaporator outlet temperature and the saturation temperature from the second evaporator outlet temperature detecting means and the saturation temperature detecting means. , The operation mode detected by the operation mode detection means is the ice heat storage operation In this case, first, the ice heat storage operation refrigeration cycle is operated, and the first and second flow path switching means are switched and controlled in accordance with the temperature difference calculated by the temperature difference calculation means to perform the ice heat storage operation. It is something to do.

[0020]

The present invention has the following actions due to the above means.

That is, a sixth flow path switching means and a receiver are provided between the third flow path switching means and the branch point of the second bypass circuit on the second condenser side, and the second flow path switching means and the receiver are provided. A seventh flow path switching means is provided between the bypass circuit of the receiver and the receiver, operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilization cooling operation is provided, and a receiver top temperature detection for detecting the receiver top temperature. Means and a saturation temperature detecting means for detecting a saturation temperature of the receiver upper part, and a differential temperature for calculating a temperature difference between the receiver upper temperature and the saturation temperature from the receiver upper temperature detecting means and the saturation temperature detecting means. When the operation mode detected by the operation mode detection means is an ice heat storage operation, first, an ice heat storage utilization operation refrigeration cycle is operated, and the temperature difference calculation means is provided. According to the calculated differential temperature, the sixth
By performing switching control of the seventh flow path switching means and performing the ice heat storage operation, the most efficient operation can be performed during the cold storage operation and the cold discharge operation, and energy can be saved.

Further, a sixth flow path switching means and a receiver are provided between the third flow path switching means and a branch point of the second bypass circuit on the second condenser side, and the second flow path switching means and the receiver are provided. A seventh flow path switching means is provided between the bypass circuit of the receiver and the receiver, operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilization cooling operation is provided, and a receiver top temperature detection for detecting the receiver top temperature. Means and a saturation temperature detecting means for detecting a saturation temperature of the receiver upper part, and a differential temperature for calculating a temperature difference between the receiver upper temperature and the saturation temperature from the receiver upper temperature detecting means and the saturation temperature detecting means. When the operation mode detected by the operation mode detecting means is an ice heat storage operation, the operation of the primary side circuit and the operation of the secondary side circuit using the ice heat storage refrigeration cycle are performed. In accordance with the temperature difference calculated by the temperature difference calculating means, the sixth and seventh flow path switching means are switched and controlled, and the ice heat storage operation is performed. Good driving is possible and energy saving can be achieved.

Further, there is provided operation mode detection means for detecting the ice heat storage operation or the ice heat utilization cooling operation, and the second evaporator outlet temperature detection means for detecting the outlet temperature of the second evaporator and the above Saturation temperature detecting means for detecting the saturation temperature of the second evaporator outlet portion is provided, and the second evaporator outlet portion temperature is calculated from the second evaporator outlet portion temperature detecting means and the saturation temperature detecting means. A temperature difference calculating means for calculating a temperature difference from the saturation temperature is provided, and when the operation mode detected by the operation mode detecting means is an ice heat storage operation, first, an ice heat storage utilization operation refrigeration cycle is operated, and the difference According to the temperature difference calculated by the temperature calculation means, the first and second flow path switching means are switched and controlled, and the ice heat storage operation is performed, so that the most efficient operation is performed during the cold storage operation and the cold discharge operation. Energy saving It is possible to achieve the ghee.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle diagram in a first embodiment of a cold storage system with a refrigerant amount control function of the present invention.

In the figure, this cold storage system comprises a primary side circuit in which the primary side refrigerant circulates and a secondary side circuit in which the secondary side refrigerant circulates.

The primary side circuit is an electric expansion valve in which the valve opening degree can be pulse-controlled using an inverter-driven variable frequency compressor 1 (hereinafter simply referred to as compressor), a first condenser 2, and a stepping motor. 3 and the first evaporator 4 are sequentially connected to form a refrigeration cycle.

In the secondary side circuit, a refrigerant pump 5 for delivering a secondary side liquid refrigerant and a cold storage tank 6 are installed. Similarly, cold storage heat that absorbs heat from water in the cold storage tank 6 to generate ice on its surface. The exchanger 7, the second condenser 8 used only in the cold storage operation for storing ice heat, and the second evaporator 9 used only in the cooling operation for extracting the cold heat from the produced ice to perform the cooling operation. , Solenoid valves 10a that open and close depending on the operation mode, 1
0b, 10c, 10d, a bypass circuit 11 that connects the outlet of the cold storage heat exchanger 7 and the refrigerant pump inlet during the cooling operation, and a solenoid valve 10e that is opened to the bypass circuit only when the cooling is performed.
Is provided. Further, in the present invention, the receiver 12 capable of storing the refrigerant liquid in front of the refrigerant pump 5, the saturation temperature sensor 13 for detecting the saturation temperature, the receiver upper temperature sensor 14 for detecting the temperature of the receiver upper portion, the liquid refrigerant in the receiver 12 Solenoid valve 10 that switches circuits for delivery
f and 10g are provided.

The first evaporator on the primary side and the second condenser used only during the cold storage operation on the secondary side are integrated into one refrigerant-refrigerant heat exchanger, where the secondary side is provided. Heat is transferred from the refrigerant to the primary side refrigerant.

During the cold storage operation for storing ice heat, both the primary side circuit and the secondary side circuit are operated. In the secondary side circuit, the secondary side refrigerant having a temperature lower than that of the water in the cold storage tank 6 is delivered from the refrigerant pump 5, passes through the electromagnetic valve 10a and enters the cold storage heat exchanger 7, where it absorbs heat from the water. After being gasified, it passes through the solenoid valve 10b and enters the second condenser 8, where heat is released to the primary side refrigerant, liquefies and returns to the refrigerant pump 5, thereby forming a refrigeration cycle. Then, as the water temperature lowers, the secondary side refrigerant temperature also lowers, and when the temperature becomes lower than zero, ice begins to be generated on the outer surface of the cold storage heat exchanger 7 and gradually grows.

During the cooling operation in which cold heat is taken out from the produced ice to perform the cooling operation, only the secondary side circuit is operated without operating the primary side circuit. In the secondary side circuit, the secondary side liquid refrigerant sent out from the refrigerant pump 5 passes through the solenoid valve 10c to the second side.
After passing through the solenoid valve 10d and entering the cold storage heat exchanger 7 from the opposite direction to the cold storage operation, the cooling operation is performed to remove the heat from the air and gasify it. Also, a refrigeration cycle is formed in which heat is released to water and liquefied, passes through the bypass circuit 11 and the electromagnetic valve 10e, and returns to the refrigerant pump 5.

Therefore, a method of controlling the solenoid valve during the preparatory operation for the cold storage operation will be described. FIG. 3 is a flowchart of a preparatory operation for the cold storage operation, and FIG. 4 is a block diagram showing a flow of opening / closing control of the solenoid valve.

First, when the signal for the cold storage operation is sent, the signal for the cold storage preparation operation is sent. At this time, the solenoid valve is controlled as shown below (Table 2).

[0034]

[Table 2]

Next, in this state, the refrigerant pump is operated to perform the cooling operation, the secondary side refrigerant is liquefied in the cold storage heat exchanger 7, and the liquid refrigerant is stored in the receiver 12. Then, the output of the saturation temperature sensor 13 is used as the saturation temperature detection circuit 1
5 is sent to the differential temperature calculation circuit 17 as a temperature signal, and the receiver upper temperature sensor 1 provided above the receiver 12
The output of No. 4 is sent from the temperature detection circuit 16 as a temperature signal to the temperature difference calculation circuit 17, where the temperature difference (= saturation temperature-receiver upper temperature) is calculated and combined with the operation mode from the operation mode determination circuit 19. And sends it to the solenoid valve setting discriminating circuit 18 to send commands to the solenoid valves 10f and 10g according to the following (Table 3) to control.

[0036]

[Table 3]

When ΔT <0, the secondary side liquid refrigerant is confined in the receiver, so that the refrigerant amount in the secondary side circuit is the most suitable refrigerant amount for the cold storage operation. It can be performed.

Next, when the signal for the cooling operation is sent, the signal for the cooling preparation operation is sent, and based on the result sent from the operation mode discriminating circuit 19, the solenoid valve 1 is set by the above (Table 3).
Controls by sending commands to 0f and 10g.

Next, when the refrigerant pump is operated in this state to perform the cooling operation, the liquid refrigerant accumulated in the receiver 12 is returned into the secondary side circuit, and the optimum secondary side refrigerant during cooling is provided. It becomes the amount.

As described above, the cooling operation is performed as the cold storage preparatory operation before the cold storage operation is started, and the secondary side refrigerant condensed and liquefied in the cold storage heat exchanger is cooled to the secondary side with the highest efficiency. By accumulating the amount of refrigerant in the receiver in front of the refrigerant pump, the most efficient operation can be performed during the cold storage operation, and energy can be saved. Also, during the cooling operation, the refrigerant accumulated in the receiver is returned to the refrigeration cycle by the opening / closing operation of the solenoid valve to circulate,
The most efficient cooling operation is possible, and energy can be saved.

Next, a second embodiment of the present invention will be described with reference to the drawings. The refrigeration cycle diagram in the second embodiment and the block diagram showing the flow of the opening / closing control of the solenoid valve during the cold storage preparation operation are the same as those in the first embodiment shown in FIGS. 1 and 4, respectively. The description is omitted.

The second embodiment differs from the first embodiment in the flow chart of the cold storage preparation operation for the cold storage operation. A flowchart at this time is shown in FIG.

That is, in the first embodiment, the liquid refrigerant is stored in the receiver 12 only by the cooling operation of the secondary side circuit as the cold storage preparation operation, whereas in the second embodiment only the cooling operation is performed. Not only that, the primary side circuit is also operated, and the liquid refrigerant is stored in the receiver by the cooling operation while supplying the liquid refrigerant to the refrigerant pump.

As described above, as the cold storage preparatory operation for the cold storage operation, not only the cooling operation of the secondary side circuit but also the primary side circuit is operated, so that sufficient liquid refrigerant is supplied to the refrigerant pump inlet. Therefore, it is possible to store the excess refrigerant for the cold storage operation in the receiver, and to perform the most efficient operation during the cold storage operation, and to save energy. Also, during the cooling operation, the refrigerant accumulated in the receiver is returned to the refrigeration cycle by the opening / closing operation of the solenoid valve and circulated, so that the cooling operation can be operated with the highest efficiency, and energy saving can be achieved. it can.

Next, a third embodiment of the present invention will be described. FIG. 6 is a refrigeration cycle diagram in the third embodiment of the cold storage system with the refrigerant amount control function of the present invention. This refrigeration cycle is different from the first and second embodiments in that the receiver 12 capable of storing the refrigerant liquid, the saturation temperature sensor 13 for detecting the saturation temperature, and the receiver upper temperature sensor for detecting the temperature of the receiver upper part 14. Solenoid valve 1 that switches the circuit to send the liquid refrigerant into the receiver 12.
0 f and 10 g are not provided, but instead, a saturation temperature sensor 20 for detecting the saturation temperature and a second evaporator outlet temperature sensor 21 for detecting the temperature of the second evaporator outlet are provided. Further, FIG. 7 is a flowchart of the cold storage preparatory operation for the cold storage operation in this embodiment, and FIG. 8 is a block diagram showing the flow of opening / closing control of the solenoid valve in this embodiment.

The third embodiment differs from the first and second embodiments in the place for storing the liquid refrigerant before the cold storage operation and the cold storage preparatory operation method.

That is, in the first and second embodiments,
While the liquid refrigerant was stored in the receiver 12 in front of the refrigerant pump, in the third embodiment, the liquid refrigerant is stored in the second evaporator during the cooling operation.

First, when the signal for the cold storage operation is sent, the signal for the cold storage preparation operation is sent. At this time, the solenoid valve is controlled as shown in the following (Table 4).

[0049]

[Table 4]

Next, in this state, the primary side circuit is operated to bring the temperature of the second condenser 8 to the saturation temperature or less with respect to the pressure of the secondary side refrigerant at that time to condense and liquefy the secondary side refrigerant, and the refrigerant pump By supplying the liquid refrigerant to 5 and operating the refrigerant pump 5 to perform the cooling operation, the secondary-side liquid refrigerant is accumulated in the second evaporator 9 during the cooling operation. Then, the output of the saturation temperature sensor 20 is sent from the saturation temperature detection circuit 22 as a temperature signal to the differential temperature calculation circuit 17, and the output of the temperature sensor 21 provided at the outlet of the second evaporator 9 is used as the second evaporator. A temperature signal is sent from the outlet temperature detection circuit 23 to the temperature difference calculation circuit 17, where the temperature difference (= saturation temperature-second evaporator outlet temperature) is calculated and the operation from the operation mode determination circuit 19 is performed. It is sent to the solenoid valve setting discriminating circuit 18 together with the mode and discriminated from the following (Table 5), and a command is sent to the solenoid valves 10c and 10d for control.

[0051]

[Table 5]

When ΔT <0, the secondary side liquid refrigerant is contained in the second evaporator, so that the refrigerant amount in the secondary side circuit is the most suitable refrigerant amount for the cold storage operation. After this, the cold storage operation can be performed.

Next, when the cooling operation signal is sent, based on the result sent from the operation mode discriminating circuit 19, a command is sent to the solenoid valve by the above (Table 5) to control. When the refrigerant pump is operated in this state to perform the cooling operation, the liquid refrigerant accumulated in the second evaporator circulates in the secondary side circuit, and becomes the optimum secondary side refrigerant amount during cooling.

As described above, before the cold storage operation is started, the primary side circuit is operated as the cold storage preparation operation, and the temperature of the second condenser is made equal to or lower than the saturation temperature with respect to the pressure of the secondary side refrigerant at that time. Inside the second evaporator up to the amount of the secondary side refrigerant that enables the most efficient cold storage operation by condensing and liquefying the refrigerant and operating the refrigerant pump while supplying the liquid refrigerant to the refrigerant pump to perform the cooling operation. Therefore, the most efficient operation can be performed during the cold storage operation, and energy can be saved. Further, during the cooling operation, the refrigerant accumulated in the second evaporator is returned to the refrigeration cycle by the opening operation of the electromagnetic valve and circulated, whereby the operation with the highest efficiency for the cooling operation can be performed and energy saving can be achieved. Can be planned.

[0055]

As is apparent from the above-described embodiment, the cold storage system of the present invention is provided between the third flow path switching means and the branch point of the second bypass circuit on the second condenser side. A sixth flow path switching means and a receiver are provided, and the second
A seventh flow path switching means is provided between the bypass circuit of the receiver and the receiver, operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilization cooling operation is provided, and a receiver top temperature detection for detecting the receiver top temperature. Means and a saturation temperature detecting means for detecting the saturation temperature of the receiver upper part,
Provided is a temperature difference calculating means for calculating the temperature difference between the receiver upper temperature and the saturation temperature from the receiver upper temperature detecting means and the saturation temperature detecting means, and the operation mode detected by the operation mode detecting means is ice heat storage. In the case of driving,
First, by operating in an ice heat storage operation refrigeration cycle, switching control of the sixth and seventh flow path switching means is performed according to the temperature difference calculated by the temperature difference calculation means, and by performing ice heat storage operation, The most efficient operation can be performed during the cold storage operation and the cold discharge operation, and energy can be saved.

Further, a sixth flow path switching means and a receiver are provided between the third flow path switching means and the branch point of the second bypass circuit on the side of the second condenser, and the sixth flow path switching means and the receiver are provided. A seventh flow path switching means is provided between the bypass circuit of the receiver and the receiver, operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilization cooling operation is provided, and a receiver top temperature detection for detecting the receiver top temperature. Means and a saturation temperature detecting means for detecting a saturation temperature of the receiver upper part, and a differential temperature for calculating a temperature difference between the receiver upper temperature and the saturation temperature from the receiver upper temperature detecting means and the saturation temperature detecting means. When the operation mode detected by the operation mode detecting means is an ice heat storage operation, the operation of the primary side circuit and the operation of the secondary side circuit using the ice heat storage refrigeration cycle are performed. In accordance with the temperature difference calculated by the temperature difference calculating means, the sixth and seventh flow path switching means are switched and controlled, and the ice heat storage operation is performed. Good driving is possible and energy saving can be achieved.

Further, there is provided operation mode detection means for detecting the ice heat storage operation or the ice heat storage utilization cooling operation, and the second evaporator outlet temperature detection means for detecting the outlet temperature of the second evaporator and the above Saturation temperature detecting means for detecting the saturation temperature of the second evaporator outlet portion is provided, and the second evaporator outlet portion temperature is calculated from the second evaporator outlet portion temperature detecting means and the saturation temperature detecting means. A temperature difference calculating means for calculating a temperature difference from the saturation temperature is provided, and when the operation mode detected by the operation mode detecting means is an ice heat storage operation, first, an ice heat storage utilization operation refrigeration cycle is operated, and the difference According to the temperature difference calculated by the temperature calculation means, the first and second flow path switching means are switched and controlled, and the ice heat storage operation is performed, so that the most efficient operation is performed during the cold storage operation and the cold discharge operation. Energy saving It is possible to achieve the ghee.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle diagram in a first embodiment of a cold storage system of the present invention.

FIG. 2 is an explanatory diagram showing system efficiency (= cold storage capacity / compressor input) in a cold storage operation when the amount of secondary side refrigerant is changed.

FIG. 3 is a flowchart of a preparatory operation for cold storage operation in the first embodiment of the cold storage system of the present invention.

FIG. 4 is a block diagram showing a flow of opening / closing control of a solenoid valve in the embodiment.

FIG. 5 is a flowchart of a cold storage preparatory operation for the cold storage operation in the second embodiment of the cold storage system of the present invention.

FIG. 6 is a refrigeration cycle diagram in the third embodiment of the cold storage system of the present invention.

FIG. 7 is a flowchart of a cold storage preparatory operation for cold storage operation in the same embodiment.

FIG. 8 is a block diagram showing a flow of opening / closing control of a solenoid valve in the embodiment.

FIG. 9 is a refrigeration cycle diagram of a conventional cold storage system.

[Explanation of symbols]

 1 Variable Capacity (Frequency) Compressor 2 First Condenser 3 Electric Expansion Valve 4 First Evaporator 5 Refrigerant Pump 6 Cold Storage Tank 7 Cold Storage Heat Exchanger 8 Second Condenser 9 Second Evaporator 10a Electromagnetic Valve 10b Solenoid valve 10c Solenoid valve 10d Solenoid valve 10e Solenoid valve 10f Solenoid valve 10g Solenoid valve 11 Bypass circuit 12 Receiver 13 Saturation temperature sensor 14 Receiver upper temperature sensor 15 Saturation temperature detection circuit 16 Receiver upper temperature detection circuit 17 Differential temperature calculation circuit 18 Solenoid valve setting discriminating circuit 19 Operation mode discriminating circuit 20 Saturation temperature sensor 21 Second evaporator outlet temperature sensor 22 Saturation temperature detecting circuit 23 Second evaporator outlet temperature detecting circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location F25B 5/02 510 H F25C 1/08 A (72) Inventor Yamaguchi Adult Kadoma City, Osaka Prefecture 1006 Kadoma Address: Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A variable capacity compressor, a first condenser, a pressure reducer, and a first evaporator are sequentially connected to constitute a refrigeration cycle of a primary side circuit, and a refrigerant pump, a cold storage heat exchanger, and a second The condensers of are connected in sequence to form the refrigeration cycle of the secondary circuit,
A first bypass circuit that bypasses between the refrigerant pump and the cold storage heat exchanger and between the cold storage heat exchanger and the second condenser is provided, and a first bypass circuit is provided on the first bypass circuit.
The flow path switching means, the second evaporator, and the second flow path switching means in this order, and between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger, and the refrigerant. A second bypass circuit that bypasses between the pump and the first condenser is provided, and a third flow path switching unit is provided on the second bypass circuit, and the first bypass pump on the refrigerant pump side is provided. Fourth flow path switching means is provided between a branch point of the bypass circuit and a branch point of the second bypass circuit on the cold storage heat exchanger side, and the first bypass on the second condenser side. A fifth point is provided between the branch point of the circuit and the second condenser.
Flow path switching means of the refrigerant pump, the fourth
Of the flow path switching means, the cold storage heat exchanger, the fifth flow path switching means, and the second condenser in this order, the ice cold storage operation in which the secondary-side refrigerant flows, the refrigerant pump, and the first flow path. The operation for switching the ice, the second evaporator, the second flow path switching means, the cold storage heat exchanger, and the third flow path switching means in order of the ice cold storage use operation in which the secondary-side refrigerant flows. Switching control is performed by the first to fifth flow path switching means,
The first evaporator on the primary side and the second condenser on the secondary side are brought into contact with each other in a heat exchange manner, and the third flow path switching means and the second bypass on the second condenser side. A sixth flow path switching means and a receiver are provided between the branch point of the circuit, and a seventh flow path switching means is provided between the second bypass circuit and the receiver, and the ice heat storage operation or the ice heat storage utilization cooling is performed. An operation mode detecting means for detecting whether the operation is performed, a receiver upper temperature detecting means for detecting the receiver upper temperature and a saturation temperature detecting means for detecting a saturation temperature of the receiver are provided, and the receiver upper temperature detecting means and the If a temperature difference calculating means for calculating a temperature difference between the receiver upper temperature and the saturation temperature is provided from a saturation temperature detecting means, and if the operation mode detected by the operation mode detecting means is ice heat storage operation, first, ice Heat storage Operating at use operating the refrigeration cycle, in accordance with the calculated differential temperature by the difference temperature calculating means, the sixth
And a cold storage system for performing an ice heat storage operation by switching and controlling the seventh flow path switching means. 2. A variable capacity compressor, a first condenser, a pressure reducer, and a first evaporator are sequentially connected to constitute a refrigeration cycle of a primary side circuit, and a refrigerant pump, a cold storage heat exchanger, and a second The condensers of are connected in sequence to form the refrigeration cycle of the secondary circuit,
A first bypass circuit that bypasses between the refrigerant pump and the cold storage heat exchanger and between the cold storage heat exchanger and the second condenser is provided, and a first bypass circuit is provided on the first bypass circuit.
The flow path switching means, the second evaporator, and the second flow path switching means in this order, and between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger, and the refrigerant. A second bypass circuit that bypasses between the pump and the first condenser is provided, and a third flow path switching unit is provided on the second bypass circuit, and the first bypass pump on the refrigerant pump side is provided. Fourth flow path switching means is provided between a branch point of the bypass circuit and a branch point of the second bypass circuit on the cold storage heat exchanger side, and the first bypass on the second condenser side. A fifth point is provided between the branch point of the circuit and the second condenser.
Flow path switching means of the refrigerant pump, the fourth
Of the flow path switching means, the cold storage heat exchanger, the fifth flow path switching means, and the second condenser in this order, the ice cold storage operation in which the secondary-side refrigerant flows, the refrigerant pump, and the first flow path. The operation for switching the ice, the second evaporator, the second flow path switching means, the cold storage heat exchanger, and the third flow path switching means in order of the ice cold storage use operation in which the secondary-side refrigerant flows. Switching control is performed by the first to fifth flow path switching means,
The first evaporator on the primary side and the second condenser on the secondary side are brought into contact with each other in a heat exchange manner, and the third flow path switching means and the second bypass on the second condenser side. A sixth flow path switching means and a receiver are provided between the branch point of the circuit, and a seventh flow path switching means is provided between the second bypass circuit and the receiver, and the ice heat storage operation or the ice heat storage utilization cooling is performed. An operation mode detecting means for detecting whether the operation is performed, a receiver upper temperature detecting means for detecting the receiver upper temperature and a saturation temperature detecting means for detecting a saturation temperature of the receiver are provided, and the receiver upper temperature detecting means and the Provided is a temperature difference calculating means for calculating the temperature difference between the receiver upper temperature and the saturation temperature from the saturation temperature detecting means, and when the operation mode detected by the operation mode detecting means is ice heat storage operation, the primary side circuit Operation and operation in a secondary side circuit using ice heat storage The operation is performed in a refrigeration cycle, and the sixth and seventh flow path switching means are controlled to be switched according to the temperature difference calculated by the temperature difference calculation means, and ice heat storage is performed. Cold storage system that operates. 3. A variable capacity compressor, a first condenser, a pressure reducer, and a first evaporator are sequentially connected to constitute a refrigeration cycle of a primary side circuit, and a refrigerant pump, a cold storage heat exchanger, and a second The condensers of are connected in sequence to form the refrigeration cycle of the secondary circuit,
A first bypass circuit that bypasses between the refrigerant pump and the cold storage heat exchanger and between the cold storage heat exchanger and the second condenser is provided, and a first bypass circuit is provided on the first bypass circuit.
The flow path switching means, the second evaporator, and the second flow path switching means in this order, and between the branch point of the first bypass circuit on the refrigerant pump side and the cold storage heat exchanger, and the refrigerant. A second bypass circuit that bypasses between the pump and the first condenser is provided, and a third flow path switching unit is provided on the second bypass circuit, and the first bypass pump on the refrigerant pump side is provided. Fourth flow path switching means is provided between a branch point of the bypass circuit and a branch point of the second bypass circuit on the cold storage heat exchanger side, and the first bypass on the second condenser side. A fifth point is provided between the branch point of the circuit and the second condenser.
Flow path switching means of the refrigerant pump, the fourth
Of the flow path switching means, the cold storage heat exchanger, the fifth flow path switching means, and the second condenser in this order, the ice cold storage operation in which the secondary-side refrigerant flows, the refrigerant pump, and the first flow path. The operation for switching the ice, the second evaporator, the second flow path switching means, the cold storage heat exchanger, and the third flow path switching means in order of the ice cold storage use operation in which the secondary-side refrigerant flows. Switching control is performed by the first to fifth flow path switching means,
The first evaporator on the primary side and the second condenser on the secondary side are brought into contact with each other in a heat exchange manner to provide an operation mode detection means for detecting an ice heat storage operation or an ice heat storage utilization cooling operation, Second evaporator outlet temperature detecting means for detecting the outlet temperature of the second evaporator and saturation temperature detecting means detecting the saturation temperature of the second evaporator outlet are provided, and the second evaporator is provided. A temperature difference calculating means for calculating a temperature difference between the second evaporator outlet temperature and the saturation temperature is provided from the outlet temperature detecting means and the saturation temperature detecting means, and the operation detected by the operation mode detecting means is provided. When the mode is the ice heat storage operation, first, the ice heat storage operation operation refrigeration cycle is operated, and the first and second flow path switching means are switched and controlled in accordance with the temperature difference calculated by the temperature difference calculating means. A cold storage system that performs ice heat storage operation.