JPS62118078A - Refrigerator - Google Patents

Abstract

PURPOSE:To carry out the control of capacity in many modes by utilizing a part of plural compressors as a motor driven compressor the which changes its number of revolution by means for frequency conversion. CONSTITUTION:A part of plural compressors 1a, 1b, 1d is a motor driven compressor 1d the speed of rotation of which can be varied by means of frequency conversion. And, the capacity of the motor driven compressor 1d can be steplessly controlled. Thereby, the total capacity of the compressors can be varied in many modes by means of the motor driven compressor, enabling a refrigerator to control the temperature in a room, a warehouse, etc. to be a desired temperature, without causing rise in cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a refrigerator used in an air conditioner or the like.

(Prior Art) Conventionally, as shown in FIG. 5, a refrigerator used in an air conditioner includes on/off type electric compressors 1a, 1b, and 1c connected in parallel, each compressor 111a, 1b,
An outdoor heat exchanger (condenser) 2 connected to the discharge side of 1C, accumulators 3a, 3b, 3c connected to the suction sides of the combined compressors 1a, 1b, and Ic, and each accumulator 3a.

It is known to have an all-inside heat exchanger 4 connected to the suction side of the heat exchangers 3b and 3c, and an expansion valve 5 connected in the pipe line between the multiple heat exchangers 2.4.

In such a refrigerator, each pressure 4I machine 1a, 1b.

When controlling the total capacity of 1C, only the compressor 1a is turned on or off, the compression 1fi1a and the compressor 1b are turned on or off, and each of the compressors 1a is controlled.

Three modes are possible when both lb and lc are turned on.

(Problems to be Solved by the Invention) In the conventional refrigerator, the total capacity of the compressors ia, 1b, and lc can only be controlled in three modes as described above, and in the air conditioner, the refrigeration capacity is divided into stages. This made it difficult to maintain the indoor temperature at the desired temperature. Also,
In order to solve this problem, the compression Vi11a, lb
Although it is possible to use 1c as an electric compressor that changes the rotation speed by frequency conversion, or to use one large compressor as an electric compressor that changes the rotation speed by frequency conversion, it is possible to use a frequency conversion device. Moreover, large compressors are expensive and have the problem of significantly increasing the cost of refrigeration.

(Object of the Invention) In view of the above-mentioned conventional problems, the present invention is capable of performing total volume control of the compressor in a large number of modes.
The objective is to provide a refrigerator that does not cause a significant increase in cost.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a plurality of compressors 1a,
In the refrigerator having compressors 1b and 1d, each compressor 1a
, lb, and 1d are made into an electric compressor 1d whose rotational speed is prevented from changing by frequency conversion.

(Function) According to the present invention, since a part of each compressor is an electric compressor that changes the rotation speed by frequency conversion, many modes of the total capacity of the combined compressor are formed by the electric compressor. .

(Embodiment) FIGS. 1 to 4 show an embodiment of the present invention, and the same components as those of the conventional example are denoted by the same reference numerals. That is,
1a, 1b, and 1d are electric compressors connected in parallel, and each of the compressors 11a and 1b is an on/off type and has a capacity of 1.
The compressor 1d is a so-called inverter type that changes the rotation speed by frequency conversion.
Its capacity can be controlled steplessly from 30kW to 120kW, but in the example, it is 30kW and 60kW.
4-stage control of W, 90kW and 120kW is shown. 2 is an outdoor heat exchanger connected to the discharge side of each of the compressors 1f11a, 1b, and ld; 3a, 3b, and 3c are the combined compressors 1a,
Accumulator connected to the suction side of 1b and 1d, 4
5 is an indoor heat exchanger connected to the suction side of each of the accumulators 3a, 3b, and 3c, and 5 is an expansion valve provided in a pipe between each of the heat exchangers 2 and 4. 6 is a pressure sensor that detects the refrigerant pressure, and each of the accumulators 3a, 3b
.

3C and the indoor heat exchanger 4.

FIG. 2 shows the control of the refrigerator according to the present invention. (1 circuit is not shown) 7 is a computer-configured controller connected to each of the compressors 1a, 1b, 1d and the pressure sensor 6, and based on the detection signal of the pressure sensor 6, controls the combined compressor 1a
1b and Id are operated and controlled as shown in FIGS. 3 and 4.

That is, ΔP represents the difference between 9/ctrlG and the current refrigerant pressure in the set pressure 11 of the refrigerant, and as shown in FIG. Based on the detection signal of ΔP≦0.2Kl/cti
When the controller 7 detects that it is G, the compression lll! The drive of the compressor 1a is stopped, and if not, the drive of the compressor a is continued. Also, if ΔP≦0.1, 9/c#i
When the controller 7 detects that the compressor 1b is G, it stops driving the compressor 1b; otherwise, the compressor 1fi1
Continue driving b.

Further, the controller 7 controls the capacity by changing the rotation speed of the compressor 1d as shown in FIG. 4 based on the detection signal of the pressure sensor 6. That is, ΔP≦0.02
5Ky/7G (hereinafter 9/ctiG will be omitted in units of F), 0.1<ΔP≦0.125.0.2<ΔP≦0,
225 is 30kW, and 0.025 <ΔP
≦0.050. 0.125<ΔP≦0.150,
When 0.225 <ΔP≦0.250, it is 60kW,
Furthermore, 0.050 <ΔP≦ 0.075, 0.150
<ΔP≦0.175, 0.250<ΔP≦0.275
When , it is 90kW, and furthermore, 0.075<ΔP≦
0.1, 0.175 <ΔP≦ 0.2, 0.275<
When ΔP, the power is 120kW. As a result, 12 capacity modes from 30kW to 320kW are created to cool the room to the desired temperature! I can do it.

Although the above embodiment describes the case where the refrigerator is used for indoor cooling in an air conditioner, it can of course be applied not only to indoor heating but also to P1 to pump cycles, and can also be applied to refrigeration and freezing. This can also be applied to 0 warehouses, etc.

(Effects of the Invention! 11 As explained above, the present invention is a refrigerator having a plurality of compressors, in which a part of each compressor is an electric compressor whose rotational speed is changed by frequency conversion. The electric compressor has the advantage of forming a large number of total capacity modes and being able to control the temperature of a room, warehouse, etc. to a desired temperature.

[Brief explanation of drawings]

1 to 4 show a refrigerator according to the present invention, and FIG. 1 is a refrigerant circuit diagram of the refrigerator used in an air conditioner;
Figure 2 is a control circuit diagram, Figure 3 is a flowchart explaining the operation of the control circuit, Figure 4 is a table explaining compressor capacity control, and Figure 5 is a diagram of a refrigerator used in a conventional air conditioner. It is a refrigerant circuit diagram. In the diagram, '1a, 1b... Compressor (on/off type), 1
d...Electric compressor (inverter type).

Claims (1)

[Claims] A refrigerator having a plurality of compressors, wherein a part of each compressor is an electric compressor whose rotational speed is changed by frequency conversion.