JPH11270914A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating device in which the number of revolution can be finely controlled depending on the operating state of the refrigerating device in a showcase, a service refrigerator, an automatic vending machine or the like. SOLUTION: A refrigerating device comprises a number-of-revolution variable compressor 1, a number-of-revolution variable condenser fan 13 and a number-of- revolution variable evaporator fan 17. The operating state of the refrigerating device is divided into an operating state of a first period of pull-down, an operating state of a period from the first pull-down to thermo-off, an operating state of a period from thermo-off to thermo-on and an operating state of a period from thermo-on to thermo-off. Further, a control means 19 is provided for variably controlling the respective numbers of rotation of the compressor 1, the condenser fan 13 and the evaporator fan 17 depending on the divided operating states.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system that saves power consumption.

[0002]

2. Description of the Related Art Generally, showcases, commercial refrigerators,
As a vending machine or the like, a refrigerating apparatus in which a compressor, a condenser, a decompression device, and an evaporator are connected by a refrigerant pipe and further provided with a condenser fan and an evaporator fan is known.

[0003]

In this type of apparatus, the number of revolutions of a compressor, a condenser fan, and an evaporator fan according to, for example, a refrigeration load is conventionally controlled, but power consumption is reduced. In view of this, no control technology has been proposed yet that performs fine rotation speed control in accordance with the operation state of the refrigeration system.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to enable fine control of the number of revolutions in a showcase, a commercial refrigerator, a vending machine or the like according to the operation state of a refrigeration system. To provide a refrigeration apparatus having a reduced size.

[0005]

According to the first aspect of the present invention,
In a refrigeration system equipped with a variable-speed compressor, a variable-speed condenser fan, and a variable-speed evaporator fan, the operation state of the refrigeration system is changed from a thermo-off, from a pull-down initial stage, from after the pull-down initial stage to a thermo-off, to a thermo-off. Control means for distinguishing between operating states from thermo on to thermo off until thermo on, and variably controlling the respective rotational speeds of the compressor, the condenser fan, and the evaporator fan according to the distinguished operating state. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect, the control means reduces the number of revolutions of the compressor and the evaporator fan at the initial stage of pull-down.

According to a third aspect of the present invention, in the first aspect, the control means decelerates the evaporator fan from thermo-off to thermo-on.

According to a fourth aspect of the present invention, in the first aspect, the control means reduces the number of revolutions of the compressor, the condenser fan, and the evaporator fan when the temperature is high outside from thermo-on to thermo-off. Further, it is characterized in that while the rotation speed of the evaporator fan is maintained at the low outside air temperature, the rotation speeds of the compressor and the condenser fan are further decelerated as compared with the high outside air temperature.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a variable speed compressor. This compressor 1 has a condenser 3,
A capillary tube (decompression device) 5 and an evaporator 7 are connected in a closed loop by a refrigerant pipe, and a condenser 3 with a variable rotation speed is attached to the condenser 3. The evaporator 7 also has a variable rotation speed evaporator fan. 17 is attached. The variable rotational speed type may be a variable type by inverter control, or may be a variable type by tap switching or the like. The evaporator 7 is installed in a storage such as a showcase, and cools the storage. Reference numeral 19 denotes a controller (control means).
Controls the following.

In FIG. 2A, the vertical axis represents the temperature inside the refrigerator such as a showcase, and the horizontal axis represents the passage of time. FIG. 2A
Referring to, when the inside of the refrigerator is cooled after the start of operation and the temperature in the refrigerator reaches a set temperature (thermo-off temperature) t1, the refrigerator enters an operation standby state (thermo-off), and this state is continued. When the internal temperature reverses and rises and reaches a set temperature (thermo-on temperature) t2, an operation state (thermo-on) is entered, and this is usually repeated to maintain the internal temperature at a substantially constant width.

According to this embodiment, the operation state of the present refrigeration system is as follows: first, a pull-down initial period (a section until a peak (point P) of the maximum torque is obtained) T1, a section T2 from the initial pull-down to a thermo-off, and a thermo-off. There are four operating states, a section T3 from the thermo-on and a section T4 from the thermo-on to the thermo-off.

FIG. 2B shows a compressor 1 and a condenser fan 1.
3 and the rotation speed control of the evaporator fan 17 are shown in comparison with a conventional example.

Incidentally, in the conventional example, each of the compressors 1 of a constant speed type,
The condenser fan 13 and the evaporator fan 17 are controlled to be turned on and off, and the on state is indicated by a circle and the off state is indicated by a cross. In the present embodiment, the respective rotation speed controls are indicated by H: high-speed rotation, M: medium-speed rotation, L: low-speed rotation, and S: stop.

Referring to FIG. 2A, in the initial pull-down period T1, the temperature inside the refrigerator decreases gradually as a whole. in this case,
In the present embodiment, as shown in FIG. 2B, the rotation speeds of the compressor 1 and the evaporator fan 17 are controlled at the medium speed M. During this time, the compressor 1 is in a so-called break-in operation, and it is not necessary to control the rotation speed of the compressor 1 with the high-speed rotation H. Therefore, the ability of the evaporator 7 is not so much required. No need to do. According to this, power saving is achieved because the number of rotations of the compressor 1 and the evaporator fan 17 is not controlled by the high-speed rotation H.

In a section T2 from the initial stage of the pull-down to the thermo-off, since the running-in operation of the compressor 1 has been completed, the compressor 1, the condenser fan 13 and the evaporator fan 13 are required to quickly reach the set temperature in the refrigerator. 1
7 is controlled by the high-speed rotation H. Operation during this time does not contribute to power saving.

In a section T3 from thermo-off to thermo-on, the operation of the compressor 1 and the condenser fan 13 is stopped S,
The rotation speed of the evaporator fan 17 is controlled by the low speed rotation L. This is to prevent frost formation on the evaporator 7,
Since the control is performed by the low-speed rotation L unlike the related art, power saving is achieved by that much.

In a section T4 from thermo-on to thermo-off, the following control is performed in relation to the outside air temperature. For example, when the outside air temperature is high (for example, 25 ° C. or more), the compressor 1, the condenser fan 13, and the evaporator fan 17
Are uniformly controlled at the medium speed M to contribute to the maintenance of the internal temperature.

On the other hand, when the outside air temperature is low (for example, less than 25 ° C.), the rotation speed of the compressor 1 and the condenser fan 13 is reduced while the rotation speed of the evaporator fan 17 is maintained at the medium rotation speed M. , At low speed L. This is because when the outside air temperature is low (for example, less than 25 ° C.), the refrigeration capacity is not so required.

According to this, power saving is achieved by controlling the number of rotations of the compressor 1 and the condenser fan 13 by the low speed rotation L.

In this embodiment, an efficient operation is performed by repeating the above control, so that power consumption can be reduced.

The present invention has been described based on one embodiment, but the present invention is not limited to this. For example, in the above embodiment, the rotation speed control is H: high speed rotation, M:
The rotation is performed in three stages of medium speed rotation and L: low speed rotation. However, the present invention is not limited to this, and linear control such as inverter control is also possible.

[0023]

According to the present invention, efficient operation is performed by variably controlling the rotational speeds of the compressor, the condenser fan, and the evaporator fan according to the operation state, thereby reducing power consumption. Can save money.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a refrigeration apparatus according to the present invention.

FIG. 2A is a diagram showing a relationship between the internal temperature and time, and FIG. 2B is a diagram showing control of the number of revolutions of a compressor, a condenser fan and an evaporator fan in comparison with a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable-speed compressor 3 Condenser 5 Capillary tube (decompression device) 7 Evaporator 13 Variable-speed condenser fan 17 Variable-speed evaporator fan 19 Controller (control means)

Claims (4)

[Claims] 1. A refrigerating apparatus comprising a variable-speed compressor, a variable-speed condenser fan, and a variable-speed evaporator fan, wherein the operation state of the refrigerating device is changed from an initial state of pull-down to an initial state of pull-down. Control for distinguishing between operating states from thermo-off, from thermo-off to thermo-on, from thermo-on to thermo-off, and variably controlling the rotational speed of each of the compressor, the condenser fan, and the evaporator fan according to the distinguished operating state. A refrigeration apparatus comprising means. 2. The refrigeration system according to claim 1, wherein said control means reduces the rotation speeds of the compressor and the evaporator fan at the initial stage of pull-down. 3. The refrigeration system according to claim 1, wherein said control means performs a deceleration operation of the evaporator fan from thermo-off to thermo-on. 4. The control means reduces the rotational speeds of the compressor, the condenser fan and the evaporator fan when the temperature is high outside, and maintains the rotational speeds of the evaporator fan when the temperature is low outside from thermo-on to thermo-off. 2. The refrigeration system according to claim 1, wherein the number of revolutions of the compressor and the condenser fan is further reduced as compared with the case of high outside air temperature.