JP2836411B2 - Ice storage operation protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ice storage operation protection device which is a protection device in an ice storage operation for storing cold heat as ice.

[0002]

2. Description of the Related Art Conventionally, there is an air conditioner having an ice storage device that accumulates cold heat as ice. This air conditioner is connected in parallel to the indoor heat exchanger in a heat pump type refrigerant circuit in which a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are sequentially connected by a refrigerant pipe. Ice storage. The flow path of the refrigerant can be switched between a flow path passing through the indoor heat exchanger and a flow path passing through the ice storage device by a valve or the like. The ice storage device has a configuration in which an ice storage type heat exchanger is installed in a water tank, and the ice storage type heat exchanger functions as an evaporator during ice storage operation to be described in detail later, while during a heat radiation operation. Functions as a condenser.

Further, the ice accumulator in the air conditioner is further arranged in parallel with the outdoor heat exchanger, and has a flow path passing through the outdoor heat exchanger and a flow path passing through the ice accumulator. It is possible to switch to.

During the cooling operation, the refrigerant gas discharged from the compressor is circulated in the order of the four-way switching valve → the outdoor heat exchanger → the expansion valve → the indoor heat exchanger → the four-way switching valve → the compressor. The refrigerant is condensed by radiating heat in the outdoor heat exchanger, decompressed by the expansion valve, absorbed by the indoor heat exchanger and evaporated to cool the room.

Further, when room cooling is not required at night or the like, the following ice storage operation is performed. That is,
The flow path of the refrigerant is switched from a flow path passing through the indoor heat exchanger to a flow path passing through the ice storage device. Then, the refrigerant gas discharged from the compressor is circulated in the order of the four-way switching valve → the outdoor heat exchanger → the expansion valve → the ice storage device → the four-way switching valve → the compressor, and the water in the ice storage device is exchanged. To make ice by heat exchange with the refrigerant, and accumulate cold heat as ice in the ice storage device. That is, the air conditioner functions as a static ice storage system during the cold storage operation.

[0006] By the way, the condensing capacity of the outdoor heat exchanger sometimes reaches a peak during the daytime in the middle of summer. In such a case, in the cooling operation described above, the evaporation capacity of the indoor heat exchanger is insufficient and the room cannot be sufficiently cooled.
At that time, the following heat dissipation operation is performed. That is, the flow path of the refrigerant is switched from the flow path passing through the outdoor heat exchanger to the flow path passing through the ice storage device. The refrigerant gas discharged from the compressor was circulated in the order of four-way switching valve → ice accumulator → expansion valve → indoor heat exchanger → four-way switching valve → compressor, and accumulated as ice in the ice accumulator. The high temperature and high pressure refrigerant gas is condensed by the cold heat.

[0007] Thus, the refrigerant is efficiently condensed even when the outside air temperature is high, so that the indoor heat exchanger is prevented from being reduced in evaporation capacity and the room is sufficiently cooled.

[0008] During the ice storage operation, water around the refrigerant pipe in the ice accumulator becomes ice due to heat exchange with the refrigerant through the refrigerant pipe and adheres to the periphery of the refrigerant pipe. FIG.
Is a schematic representation of this situation.

As shown in FIG. 5A, the ice 2a, 2b, 2c formed around the refrigerant pipe 1 grows by further cooling the surrounding water and changing it into ice. At this time, the growth of the ice 2a, 2b, 2c causes the heat transfer rate to decrease and the growth rate of the ice to decrease. On the other hand, the surface area of the ice 2a, 2b, 2c increases until the ice 2a formed around one refrigerant pipe 1 comes into contact with the ice 2b or the ice 2c formed around the adjacent refrigerant pipe 1. As a result, the growth rate increases, and as a result, the ice making capacity becomes substantially constant within a certain range of the ice storage rate. As a result, as shown in FIG. 6, the evaporation temperature (saturation temperature corresponding to low pressure) in the ice storage type heat exchanger in the ice storage device does not change much.

[0010] Further, the growth of ice proceeds, the ice storage rate increases,
Eventually, as shown in FIG. 5B, the adjacent ice 2a, ice 2b and ice 2c come into contact. Then, since the surface area of the ice block rapidly decreases, the heat exchange efficiency of the ice storage type heat exchanger decreases, and the evaporation temperature sharply decreases as shown in FIG. Therefore, if left unattended, the compressor may be compressed and damaged.

Therefore, conventionally, an ice storage sensor is provided, and a signal from the ice storage sensor detects that the ice storage rate is at a limit and stops the cold storage operation.

However, the air conditioner having the conventional ice storage device has the following problems. That is, the ice storage sensor electrically detects the ice storage ratio by measuring the impedance of the ice or the pressure of the ice between the two electrodes, and is expensive, so that the cost is increased.

Also, since there is no protection device especially on the compressor side, if the ice storage sensor fails, there is no way to stop the compressor when the ice storage rate reaches the limit. However, there is a problem that when a failure occurs, the compressor also fails at the same time.

An object of the present invention is to provide an ice storage operation protection device that detects an ice storage rate being at a limit and automatically terminates the ice storage operation without providing an expensive ice storage sensor. It is in.

[0014]

To achieve the above object, the invention according to claim 1 detects a temperature corresponding to an evaporation temperature in an ice storage type heat exchanger and outputs a temperature signal representing the detected temperature. A temperature detection unit and an ice storage stop temperature corresponding to an evaporating temperature in a state where ice around adjacent pipes of the ice storage type heat exchanger are connected to each other and integrated are compared with a temperature detected by the temperature detection unit. Then, when the detected temperature is lower than the ice storage stop temperature, the compressor stop determination unit that determines that the compressor should be stopped, and the compressor that receives the determination result of the compressor stop determination unit and starts the compressor. The compressor is provided with a compressor stop unit for stopping the compressor.

[0015]

[0016]

[0017]

In the invention according to the first aspect, the detected temperature based on the temperature signal from the temperature detecting unit and the ice around the adjacent pipe of the ice storage type heat exchanger are connected to each other by the compressor stop judging unit. The ice storage stop temperature corresponding to the evaporation temperature in the integrated state is compared. When the detected temperature is lower than the ice storage stop temperature, it is determined that the compressor should be stopped. Then, in response to this determination result, the compressor is stopped by the compressor stop unit, and the ice storage operation is ended.

[0018]

[0019]

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is a schematic sectional view of an ice storage device 11 according to the present embodiment. An ice storage type heat exchanger 16 comprising a meandering refrigerant pipe 13 is arranged in a rectangular parallelepiped housing 14, and the ice storage type heat exchanger 1 is connected to an outlet pipe 15 of the ice storage type heat exchanger 16.
Thermistor 13 for detecting the evaporation temperature of No. 6 is attached.

As described above, during the ice storage operation, the low-temperature and low-pressure refrigerant from the expansion valve flows into the refrigerant pipe 12 of the ice storage type heat exchanger 16, and the refrigerant pipe of water and refrigerant in the housing 14. Ice is formed by heat exchange via 12. At that time, FIG.
As shown in the figure, the evaporation temperature in the ice storage type heat exchanger 16 changes. Therefore, in this embodiment, the limit of the ice storage rate is detected by detecting the evaporation temperature in the ice storage heat exchanger 16 by the thermistor 13.

FIG. 2 is a block diagram of the ice storage operation protection device in this embodiment. The ice storage operation protection device detects the heat of evaporation in the ice storage heat exchanger 16 and predicts the limit of the ice storage rate, and automatically stops the compressor 26 based on the prediction result.

During the ice storage operation, the outflow pipe 15
The refrigerant pipe temperature (corresponding to the evaporation temperature; hereinafter, referred to as the evaporation temperature) detected by the thermistor 13 attached to the
The temperature signal is converted into a digital temperature signal by the / D converter 21 and input to the compressor stop determination unit 22. Then, the compressor stop determination unit 22 monitors the evaporation temperature T based on the temperature signal from the A / D converter 21. The evaporating temperature T decreases as the growth of ice progresses as shown in FIG. 3, and immediately before the stable period in which the ice making capacity becomes substantially constant, the set temperature stored in the set temperature storage unit 23 in advance. The temperature reaches “T ₀ ”.

Then, the compressor stop judging section 22 starts the timer 24 set at the predetermined time “t ₀ ”. Then, when a time signal indicating that the predetermined time “t ₀ ” has elapsed is input from the timer 24, it is determined that the ice storage rate has reached the limit, and the compressor stop unit 25 is instructed to stop the compressor 26. Output a stop command signal. The compressor stop unit 25 stops the compressor 26 based on a stop command signal from the compressor stop determination unit 22.

At this time, as shown in FIG. 3, the set temperature “T ₀ ” is set to a temperature immediately before the ice making capacity stabilization period, and the predetermined time “t ₀ ” is set to the end of the ice making capacity stabilization period. Set the time immediately before By doing so, the compressor 26 can be automatically stopped before the end of the ice making capacity stabilization period and before the evaporation temperature T sharply decreases and at the time when a high ice storage rate is exhibited. The length of the ice making capacity stabilization period varies depending on the outside air temperature. Therefore, the set time of the timer 24 is changed by the time setting unit 27 including a numeric keypad or the like, and the set time of the timer 24 is optimally set according to the outside air temperature.

That is, the temperature detector is constituted by the thermistor 13 and the A / D converter 21 and the timer 24
This constitutes the clock section.

FIG. 4 is a flowchart of the ice storage operation protection processing operation executed under the control of the compressor stop judging section 22. Hereinafter, the ice storage operation protection processing operation will be described with reference to FIG. In step S1, the A / D converter 2
The temperature signal from 1 is taken in, and the evaporation temperature T is detected. In step S2, it is determined whether or not the detected evaporation temperature “T” has become lower than the set temperature “t ₀ ”. As a result, if it becomes lower than the set temperature “T ₀ ”, step S
Proceed to 3.

In step S3, the timer 24 is started, and a time t from when the evaporation temperature T becomes lower than the set temperature "T ₀ " is measured. If the time t is equal to or longer than the predetermined time “t ₀ ” in step S4, the compressor is stopped and the ice storage operation is terminated. In step S5, the timer 24 is reset, and the ice storage operation protection processing operation ends.

As described above, in the present embodiment, the thermistor 13 is attached to the outflow pipe 15 of the ice storage type heat exchanger 16 of the ice storage device 11. Then, the compressor stopping unit 22
As a result, the evaporation temperature “T” of the ice storage heat exchanger 16 based on the temperature signal from the thermistor 13 is changed to the set temperature “T ₀ ”.
If it is determined that the lower time has continued for the predetermined time “t ₀ ” or more, the compressor stopping unit 25 is controlled to
6 is stopped. Therefore, without using an expensive ice storage sensor, the ice storage operation can be ended before the evaporation temperature in the ice storage heat exchanger 16 suddenly decreases. That is, the present embodiment can sufficiently fulfill the function as the compressor protection device during the ice storage operation.

In the above embodiment, the set temperature "T
₀ "the predetermined time""determines the蓄氷operation end, based on the. However, the set temperature" t ₀ is around ice adjacent refrigerant tubes蓄氷heat exchanger 16 to T ₀ " While the ice storage stop temperature corresponding to the evaporating temperature in the connected and integrated state is set, while the predetermined time “t ₀ ” is set to zero, the ice around the adjacent refrigerant pipe of the ice storage heat exchanger 16 is reduced. The ice storage operation may be terminated immediately at the time of being connected and integrated.

In the above embodiment, the thermistor 13 is attached to the outlet pipe 15 of the ice storage type heat exchanger 16, but may be attached to the inlet pipe. Alternatively, the ice storage 11
It may be attached so that the water temperature inside can be detected. The algorithm of the ice storage operation protection processing operation is not limited to the flowchart shown in FIG.

[0032]

As is apparent from the above description, in the ice storage operation protection apparatus according to the first aspect of the present invention, the compressor stop judging unit and the ice storage type heat exchange system detect the temperature based on the temperature signal from the temperature detecting unit. Comparing the ice storage stop temperature corresponding to the evaporation temperature in a state where the ice around the pipes adjacent to the vessel is connected and integrated, and compresses when the detected temperature falls below the ice storage stop temperature. It is determined that the compressor should be stopped, and the compressor is stopped by the compressor stop unit, so that the ice around the adjacent pipes of the ice storage heat exchanger is connected to each other and integrated with the evaporation temperature in an integrated state. Ice storage operation can be terminated immediately. Therefore, according to the present invention, without providing an expensive ice storage sensor, the ice storage operation can be automatically terminated by detecting that the ice storage rate is at a limit, and a low-cost and highly reliable ice storage operation can be performed. It is possible to realize an air conditioner or the like that can perform the operation.

[0033]

[0034]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a state where a thermistor is mounted in an ice storage operation protection device of the present invention.

FIG. 2 is a block diagram of an ice storage operation protection device that operates based on a signal from the thermistor of FIG. 1;

FIG. 3 is an explanatory diagram of an operation of the ice storage operation protection device shown in FIG. 2;

FIG. 4 is a flowchart of an ice storage operation protection process operation performed by a compressor stop determination unit in the ice storage operation protection device shown in FIG. 2;

FIG. 5 is an explanatory diagram of an ice making process in the ice storage type heat exchanger.

6 is a diagram showing a relationship between an ice storage rate and an evaporation rate of an ice storage heat exchanger in the ice making process shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Ice storage device, 13 ... Thermistor, 15 ... Outflow pipe, 16 ... Ice storage type heat exchanger, 22 ... Compressor stop determination part, 23 ...
Set temperature storage unit, 24 timer
26: compressor, 27: time setting unit.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-210774 (JP, A) JP-A-1-210775 (JP, A) JP-A-49-61742 (JP, A) 47451 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F25B 47/02 570 F25B 1/00 320 F25B 1/00 341

Claims (1)

(57) [Claims] A temperature detecting unit for detecting a temperature corresponding to an evaporation temperature in the ice storage type heat exchanger and outputting a temperature signal representing the detected temperature; Comparing the ice storage stop temperature corresponding to the evaporating temperature in the state where the ice around the adjacent pipes of the vessel (16) is connected to each other and integrated with the detected temperature from the temperature detection unit (13, 21), When the detected temperature is lower than the ice storage stop temperature, a compressor stop determination unit (22) that determines that the compressor (26) should be stopped, and a determination result of the compressor stop determination unit (22). An ice storage operation protection device comprising a compressor stop (25) for receiving the compressor (26) and stopping the compressor (26).