JPH11108475A - Freezer and method for proportionally controlling freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a proportional precise cooling control to be attained over the entire range of 0 to 100% of a motor output by a method wherein there is provided a compressor control means for operating the compressor when a pressure within a refrigerant gas tank is out of a range of predetermined pressure. SOLUTION: A refrigerant liquid sent to a first evaporator 15 and a second evaporator 16 is evaporated and gasified to cool a cooling coil with a gasification heat at this time and then the refrigerant is stored in a refrigerant gas tank 18. As a pressure within the refrigerant gas tank 18 is increased up to a predetermined pressure (for example, 3 kg/cm<2> ), a pressure sensor 21 constituting a compressor control means may detect this increased state, a compressor 11 is operated to feed refrigerant gas from the refrigerant gas tank 18 to the compressor 11, the refrigerant is compressed, thereafter the refrigerant is fed into a condenser 12. In addition, as a pressure in the refrigerant gas tank 18 is decreased to a predetermined value (for example, 1 kg/cm<2> ), its feeding is stopped. With such an arrangement as above, it becomes possible to perform a stepless proportional control within a range of 0 to 100% of a motor output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigerator and a proportional control method thereof. More specifically, in a direct expansion type refrigerator, the cooling control is performed at 0 to 100% of the motor output.
The present invention relates to a refrigerator and a proportional control method thereof, which can be precisely performed by proportional control in the entire range up to.

[0002]

2. Description of the Related Art In recent years, more precise cooling control has been required in, for example, semiconductor manufacturing factories, printing factories, noodle making factories, various test rooms, and the like. In particular, in a test room using a precise testing machine, a precise cooling control of ± 0.1 ° C. is required. Air conditioning of these test rooms and the like is performed by an air conditioner (hereinafter, referred to as an air conditioner). The air conditioner is provided with a refrigerator, and the refrigerator includes a direct expansion type (hereinafter, referred to as a direct expansion type) and a chiller type. The direct expansion method is a method in which a refrigerant liquid is sent to an evaporator, expanded and vaporized in a coil, cools the coil, and exchanges heat with passing air to perform cooling. The chiller method is a method in which heat is exchanged with water by an evaporator to produce cooling water, the cooling water is circulated through a cooling coil or the like, and heat is exchanged with air to perform cooling.

[0003]

The above system has the following problems. In other words, the direct expansion method is a structure that directly exchanges heat with air, and therefore has a simple structure and excellent heat exchange efficiency.However, in order to control cooling while operating continuously, refrigerant is always supplied to the cooling coil. I need to send in. However, since a certain torque is required to drive the compressor of the refrigerator (compressor), control is impossible in a range where the motor output cannot drive the compressor (normally, about 0 to 30%). , Proportional control is possible for about 3 outputs
It was limited to the range of 0-100%. Therefore, in the direct expansion system, precise cooling control is difficult only by proportional control of the motor output.

[0004] On the other hand, in the chiller system, water is once cooled, and the cooling water is used to perform cooling and dehumidification. Therefore, the cooling capacity can be maintained without constantly operating the compressor. Further, the cooling water is circulated by a pump, and proportional control over the entire range of 0 to 100% of the output of the pump is possible. However, on the other hand, there is a problem that the installation cost and the running cost become high as a whole device, for example, equipment for cooling and storing water and the above-mentioned pump for constantly circulating cooling water are required. Was.

The inventor of the present invention has made various studies to make use of the above-mentioned features of the direct expansion type refrigerator and to solve the drawbacks thereof. The refrigerant liquid condensed in the condenser is stored in a tank, and the refrigerant in the tank is stored in the tank. By paying attention to whether precise cooling control can be performed by feeding the refrigerant liquid to the evaporator by proportional control using the pressure of the refrigerant liquid, the present invention has been completed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In a direct expansion type refrigerator, it is possible to perform cooling control by a proportional type in a whole range from 0 to 100% of a motor output which has been difficult in the past. An object of the present invention is to provide a refrigerator capable of performing precise cooling control and a proportional control method thereof.

[0007]

Means for Solving the Problems The constitution of the invention taken to solve the above problems is as follows. According to a first aspect, there is provided a direct expansion type refrigerator including a compressor, a condenser, and an evaporator, wherein the refrigerator is provided between the condenser and a refrigerant liquid introduction side of the evaporator. A refrigerant liquid tank for storing refrigerant liquid; refrigerant liquid proportional control means for performing proportional control of the refrigerant liquid sent from the refrigerant liquid tank to the evaporator; a refrigerant gas outlet side of the evaporator; and the compressor. A refrigerant gas tank that stores refrigerant gas, and compressor control means that operates the compressor when the pressure in the refrigerant gas tank is within a predetermined pressure range. It is a refrigerator characterized by the above-mentioned.

According to a second aspect of the present invention, there is provided a proportional control method for a direct expansion type refrigerator including a compressor, a condenser, and an evaporator, wherein the refrigerant liquid liquefied by the condenser is a refrigerant liquid. Storing in the storage means, feeding the stored refrigerant liquid to the evaporator by proportional control, cooling the heat medium by evaporating the refrigerant liquid in the evaporator, and cooling the refrigerant gas evaporated in the evaporator. Storing the refrigerant gas in the refrigerant gas storage means, compressing the stored refrigerant gas by operating the compressor when the pressure of the stored refrigerant gas is within a predetermined pressure range, and liquefying the refrigerant gas in the condenser; A proportional control method for the refrigerator.

(Operation) As described above, in a conventional direct expansion type refrigerator, cooling is controlled by operating a compressor by a motor and sending refrigerant liquid to an evaporator such as a cooling coil. Therefore, the proportional control of the output range less than the minimum motor output that can operate the compressor could not be performed. According to the present invention, the cooling control is performed by feeding the refrigerant liquid stored in the tank to the evaporator by the refrigerant liquid proportional control means such as an electromagnetic valve. It is not directly affected by the operation of the machine. The operation of the compressor is controlled by compressor control means for sensing the pressure of the refrigerant gas stored in the tank, and the refrigerant liquid tank is sequentially replenished with the refrigerant liquid. Therefore, even when the compressor is operating or stopped, the refrigerant liquid proportional control means controls the output range below the minimum motor output at which the compressor can operate, in the range of 0 to 100% of the motor output. Stepless proportional control becomes possible. In addition, although there is a time restriction, it is possible to supply a refrigerant amount exceeding the output of the compressor motor, so that it can be used more widely than conventional circuits.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to the embodiments shown in the drawings. FIG. 1 is a schematic explanatory view of an air conditioner using a refrigerator according to the present invention. The air conditioner C has a refrigerator 10. The refrigerator 10 includes a compressor 11, a condenser 12, and a first evaporator 1 that is a heat exchanger.
5 is a direct expansion type refrigerator including a fifth evaporator 16 and a second evaporator 16. As the compressor 11, various types such as a rotary type, a scroll type, and a reciprocating type can be used.

A refrigerant liquid tank 17 is provided between the condenser 12 and the first and second evaporators 15 and 16 for temporarily storing the refrigerant liquid liquefied by the condenser 12. The internal pressure of the refrigerant liquid tank 17 becomes high. Further, between the refrigerant liquid tank 17 and the first and second evaporators 15 and 16, there are provided capillary tubes 13 and 14 and electromagnetic valves 19 and 20 which constitute refrigerant liquid proportional control means. The solenoid valves 19 and 20 are controlled to be opened and closed by a proportional control device which also constitutes a refrigerant liquid proportional control means. A typical example of the proportional control device is a system that detects a difference between a set temperature and an outlet temperature and controls the opening and closing of the solenoid valves 19 and 20 according to the temperature difference.

Between the first evaporator 15 and the second evaporator 16 and the compressor 11, a refrigerant gas tank 18 for temporarily storing the refrigerant gas evaporated in the first evaporator 15 and the second evaporator 16 is provided. Is provided. The internal pressure of the refrigerant gas tank 18 is relatively low. The first evaporator 15 and the second evaporator 16 are installed in the air conditioning control room 30. The air-conditioning control room 30 mainly includes a dehumidification control room 31 for producing dehumidification control air.
And a cooling control chamber 32 for mainly producing cooling control air. The first evaporator 15 is provided in the dehumidification control chamber 31.
The second evaporators 16 are arranged in the cooling control chamber 32, respectively.

A blower 33 is provided in the air-conditioning control room 30 to send air to a dehumidification control room 31 and a cooling control room 32. The dehumidification control chamber 31 is provided with an air volume control shutter 34 for controlling the air volume of the inflowing air. The air discharged from the dehumidification control room 31 and the cooling control room 32 is sent to the air conditioning room 40, and the air discharged from the air conditioning room 40 returns to the air conditioning control room 30. It should be noted that when the blowout and suction directions of the blower 33 are reversed, and the first evaporator 15 and the second evaporator 16 and the like are arranged on the suction side, temperature adjustment and humidity adjustment are individually performed. The blown air can be stirred by the blower 33, and the blown air can be made uniform. Reference numeral 36 denotes a humidifier that operates when the humidity is too low, and reference numeral 35 denotes a heater that operates when the temperature is too low.

(Operation) The operation of the air conditioner C according to the present invention will be described with reference to FIG. The compressor 11 sucks and compresses the refrigerant gas stored in the refrigerant gas tank 18 and then sends it to the condenser 12. In the condenser 12, the high-temperature and high-pressure refrigerant gas is liquefied, and the latent heat released at this time is cooled by a fan (not shown). The liquefied refrigerant liquid is stored in the refrigerant liquid tank 17. Air conditioning room 40
When the solenoid valves 19 and 20 are opened and closed in a time proportional manner in accordance with the cooling and dehumidifying conditions, the refrigerant liquid is discharged from the refrigerant liquid tank 17 for one of the first evaporator 15 and the second evaporator 16 for a required time. Or, it is sent to both, and control air is created in the air conditioning control room 30.

The refrigerant liquid sent to the first evaporator 15 and the second evaporator 16 evaporates and evaporates, and the cooling coil (included in the evaporator) is cooled by the heat of vaporization at this time, and the refrigerant gas tank is cooled. 18 is stored. When the pressure in the refrigerant gas tank 18 rises to a predetermined pressure (for example, 3 kg / cm2), the pressure sensor 21 constituting the compressor control means senses this and sends a signal to the operation switch 22 of the compressor 11, The compressor 11 is operated to send the refrigerant gas from the refrigerant gas tank 18 to the compressor 11, compresses the refrigerant gas, and then sends it to the condenser 12. When the pressure in the refrigerant gas tank 18 decreases to a predetermined pressure (for example, 1 kg / cm 2), the supply is stopped. The pressure value of the refrigerant gas serving as a reference for operating the compressor 11 is not limited to the pressure value in the refrigerant gas tank 18, but may be in a low-pressure circuit (for example, in the refrigerant gas tank 18) depending on the circuit configuration of the refrigerator. It is also possible to substitute the pressure values in the front and rear feed pipes). Thus, the air conditioner C and the refrigerator 10 are operated by repeating the above cycle.

As described above, the control of the cooling and dehumidification of the air-conditioning chamber 40 is performed by controlling the refrigerant liquid stored in the refrigerant liquid tank 17 by
Since the solenoid valves 19 and 20 are used to feed the first evaporator 15 and the second evaporator 16 by time proportional control, the operation of the compressor 11 by the motor is directly performed. Is not affected. Also, the compressor 11
The operation of the refrigerant gas tank 18 is controlled by a pressure sensor 21 for sensing the pressure of the refrigerant gas stored in the refrigerant gas tank 18 and the operation switch 22, and the refrigerant liquid tank 17 is sequentially replenished with the refrigerant liquid. Therefore, even when the compressor 11 is operating or stopped, the stepless operation in the range of 0 to 100% of the motor output including the control of the output range below the minimum motor output that can operate the compressor 11 is performed. Can be proportionally controlled. Furthermore, since the amount of refrigerant that cannot be obtained with a normal motor output of 100% can be supplied in a short time, an effect that can cope with a sudden change in temperature due to disturbance can be expected.

Further, in the air conditioner of the present invention, air is circulated through the dehumidification control chamber 31 and the cooling control chamber 32 provided with the first evaporator 15 and the second evaporator 16, respectively, to perform cooling and dehumidification. Like that. That is, the cooling control chamber 32
Then, the air is circulated to exchange heat with the second evaporator 16 for cooling. In the dehumidification control chamber 31, the air flow rate control shutter 34 lowers the air flow speed and lowers the air flow to perform the first evaporation. The heat exchange with the vessel 15 is performed, thereby cooling and dehumidifying the air. Although the air volume of the air flowing through the dehumidification control chamber 31 is small, the total air volume of the cooling control chamber 32 and the dehumidification control chamber 31 is the same.
Air is efficiently circulated in the device.

As described above, the dehumidification can be performed in the dehumidification control chamber 31 while efficiently circulating the air in the air-conditioning chamber 40 and securing a sufficient air volume for stabilizing the distribution of temperature and humidity uniformly. . Further, the control of the cooling and dehumidification can be precisely controlled by appropriately allocating and adjusting the air for the cooling control and the air for the dehumidification control by the air volume control shutter 34. Further, when dehumidifying, it is possible to prevent wasteful consumption of energy such as adjusting the temperature by operating the heater while operating the refrigerator 1.

It should be noted that the terms and expressions used in the present specification are merely illustrative and not restrictive, and the terms described in the present specification and terms equivalent to a part thereof are used. There is no intention to exclude words or expressions. Further, the present invention is not limited to the illustrated embodiment, and it goes without saying that various modifications can be made within the scope of the technical idea of the present invention.

[0020]

The present invention has the above configuration and has the following effects. That is, according to the present invention, the control of the cooling is performed by feeding the refrigerant liquid stored in the tank to the evaporator by the refrigerant liquid proportional control means such as an electromagnetic valve. It is not directly affected by the operation of the compressor. The operation of the compressor is controlled by compressor control means for sensing the pressure of the refrigerant gas stored in the tank, and the refrigerant liquid tank is sequentially replenished with the refrigerant liquid. Therefore, whether the compressor is operating or stopped, the refrigerant liquid proportional control means
0-100% of motor output, including control of output range below the minimum motor output that can operate the compressor
Stepless proportional control in the range of Also,
Although there is a time constraint, it is possible to supply a refrigerant amount exceeding the output of the compressor motor, so that it can be used more widely than conventional circuits.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an air conditioner using a refrigerator according to the present invention.

[Explanation of symbols]

 C Air conditioner 10 Refrigerator 11 Compressor 12 Condenser 13, 14 Capillary tube 15 First evaporator 16 Second evaporator 17 Refrigerant liquid tank 18 Refrigerant gas tank 19, 20 Solenoid valve 21 Pressure sensor 22 Operation switch 30 Air conditioning Control room 31 Dehumidification control room 32 Cooling control room 33 Circulation fan 34 Flow control shutter 35 Heater 36 Humidifier 40 Air conditioning room

Claims (2)

[Claims] 1. A direct expansion type refrigerator comprising a compressor, a condenser and an evaporator, wherein a refrigerator is provided between the condenser (12) and a refrigerant liquid introduction side of the evaporator (15, 16). And a refrigerant liquid tank for storing the refrigerant liquid
(17), refrigerant liquid proportional control means for performing proportional control of the refrigerant liquid sent from the inside of the refrigerant liquid tank (17) to the evaporator (15, 16), and refrigerant gas of the evaporator (15, 16) Discharge side and the above compressor (11)
A refrigerant gas tank (18) that stores refrigerant gas, and a compressor that operates the compressor (11) when the pressure in the refrigerant gas tank (18) is within a predetermined pressure range. A refrigerator control means. 2. A compressor (11), a condenser (12) and an evaporator (15, 1).
6) A proportional control method for a direct expansion type refrigerator comprising: a step of storing the refrigerant liquid liquefied by the condenser (12) in refrigerant liquid storage means, wherein the stored refrigerant liquid is proportionally controlled. Sending the refrigerant gas to the evaporator (15, 16), evaporating the refrigerant liquid in the evaporator (15, 16) to cool the heat medium, and cooling the refrigerant gas evaporated in the evaporator (15, 16). Storing the refrigerant gas in the refrigerant gas storage means, compressing the stored refrigerant gas by operating the compressor (11) when the pressure of the stored refrigerant gas is within a predetermined pressure range, Liquefying in (12),
A proportional control method for a refrigerator.