JPH02217758A - Control device for refrigeratin machine - Google Patents

Abstract

PURPOSE:To greatly increase cooling capability by providing a refrigerant bypass circuit which leads refrigerant from a first refrigeration cycle heat exchanger through a second refrigeration cycle accumulation type heat transfer device to a first refrigeration cycle accumulator. CONSTITUTION:A bypass circuit 19 is provided which leads refrigerant from a portion between an outdoor heat exchanger 4 of a first refrigeratic cycle unit A1 and a first on-off valve 13 through a second on-off valve 18 and an accumulator type heat transfer device 17 of a second refrigeration cycle unit A2 to an accumulator 12 of the first refrigeration cycle unit A1. When there is a requirement beyond the capability of a compressor 2 of the first refrigeration cycle unit A1 in cooling operation of the first refrigeration cycle unit A1, the first on-off valve 13 is closed and the second on-off valve 18 is opened for intersystem heat transfer by the accumulation type heat transfer device 19.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a control device for a refrigeration machine equipped with two refrigeration cycles, and particularly to a control device for a refrigeration machine that significantly increases cooling capacity. be.

[Conventional technology]

FIG. 4 is a diagram showing an air conditioner equipped with a conventional refrigeration cycle control device disclosed in, for example, Japanese Unexamined Patent Publication No. 63-213755. This air conditioner includes an outdoor unit A and multiple indoor units BI.

It is divided into B2, B:+, and B4, and has two refrigerant circulation systems 1a and lb. The outdoor unit 2 A is divided into two parts corresponding to the two refrigerant circulation systems 1a and Ib, each having compressors 2a and 2b, four-way valves 3a and 3b, and an outdoor heat exchanger (evaporator) 4a.

4b is provided, and the straw is connected with a refrigerant pipe.

Further, another heat exchanger 15a, 5b is interposed on the upstream side of each outdoor heat exchanger 4a, 4b, and the compressor 2a,
The refrigerant from 2b is passed through the on-off valves 8a and 8b to the other refrigerant circulation system! a.

1b to heat exchangers 5a, 5b, where heat exchange is performed, and then passed through expansion mechanisms 7a, 7b to outdoor heat exchangers 4a, 4.
The refrigerant circuits 8a and 8b constitute heat transfer devices 9a and 9b.

Further, each of the indoor units B, to B4 is provided with an indoor heat exchanger (condenser) 10 and an expansion mechanism 11, respectively.

Next, the operation will be explained.

During heating operation, the refrigerant in the compressors 2a and 2b is circulated through the west valves 3a and 3b, the indoor heat exchange @10, the expansion mechanism 11, and the outdoor heat exchangers 4a and 4b again to the compressors 512a and 2b, and The rooms in which the units B, to B4 are arranged are heated. Also, during cooling operation, the four-way valves 3a and 3
b is switched, the flow of refrigerant is reversed, and each room is cooled. Here, two refrigerant circulation systems 1a, lb
In between, there is a heat exchanger i5 arranged upstream of the outdoor heat exchanger 4a or 4b of one refrigerant circulation system 1a or 1b.
a or 5b, and the refrigerant from the compressor 2a or 2b of the other refrigerant circulation system 1a or 1b is passed through the heat exchanger 15a or 5b and then passed through the expansion mechanism 73 or 7b to the other refrigerant circulation system 1a or 1b. A refrigerant circuit 8a or 8b that returns to the upstream side of the outdoor heat exchanger 4a or 4b.
and an on-off valve 6a disposed in the refrigerant circuit 8a or 8b.
or 6b is provided, and when the capacity of the maximum capacity device 1 of the compressor 2a or 2b of the one refrigerant circulation system 1a or 1b is required, the on-off valve 6a or 6b is opened. Thereby, the heating capacity of the other refrigerant circulation system 1a or 1b is increased.

(Problem to be Solved by the Invention) However, in the control device for a refrigeration machine as described above, the high temperature gas refrigerant discharged from the compressor of one refrigeration circulation system and the evaporator of the other refrigerant circulation system ( Since heat is transferred between the low-pressure refrigerant near the inlet of the outdoor heat exchanger), the refrigerant in the other evaporator is used where it has a high degree of freshness, and therefore the heat inside the evaporator is There is a problem in that the efficiency of the refrigeration cycle decreases because it is used where the transmission rate is low, and an increase in cooling capacity cannot be expected during cooling operation.

This invention was made to solve these problems, and aims to provide a control device for a refrigeration machine that has a high efficiency refrigeration cycle and can significantly increase cooling capacity during cooling operation. The purpose is

[! ! Means for resolving columns]

A control device for reducing refrigeration by 711 units according to the present invention includes a first refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, and an accumulator are sequentially connected by refrigerant piping, a compressor, a condenser,
A control device for a refrigeration machine equipped with two refrigeration cycles, a second refrigeration cycle in which an expansion mechanism and an accumulator type heat transfer device are sequentially connected by refrigerant piping, the control device comprising: an outdoor heat exchanger of the first refrigeration cycle; A first opening T11 valve is provided on the downstream side, and the first opening T11 valve is provided between the outdoor heat exchanger and the first opening/closing valve through the second opening/closing valve and the accumulator type heat transfer device of the second refrigeration cycle. A bypass circuit is provided to guide the refrigerant to the accumulator of the refrigeration cycle, and the first 7fJ
During cooling operation of the refrigeration cycle, when there is a demand that exceeds the capacity of the compressor of the first refrigeration cycle, the first ! A1
One valve is closed, the second on-off valve is opened, and the accumulator type heat transfer device is configured to transfer heat between systems.

(Operation) In the refrigeration machine control device of the present invention, a bypass circuit for guiding refrigerant from the heat exchanger of the first refrigeration cycle to the accumulator of the first refrigeration cycle through the accumulator type heat transfer device of the second refrigeration cycle is provided. When the capacity of the compressor is exceeded during cooling operation of the first refrigeration cycle, the refrigerant flows into the bypass circuit, and inter-system heat transfer is performed in the accumulator type heat transfer device of the second refrigeration cycle.

(Embodiment) Fig. 1 is a block diagram showing an embodiment of the present invention, showing a refrigerant circuit of an air conditioner.This air conditioner is composed of an outdoor unit A and a plurality of indoor units B. ,
The outdoor unit A has two systems: a first refrigeration cycle unit A and an auxiliary second refrigeration cycle unit A.

The first refrigeration cycle unit A1 includes a compressor 2.
Four-way valve 3. An outdoor heat exchanger 4 and an accumulator 12 for exchanging heat between high and low pressures are provided, and a first on-off valve 13 is provided on the downstream side of the outdoor heat exchanger 4. The stiffeners are successively connected by refrigerant piping. The second refrigeration cycle unit A2 includes a compressor 14. Condenser 15.
An expansion mechanism 16 and an accumulator type heat transfer device 17 are provided, and these are sequentially connected by refrigerant piping. And the outdoor heat exchanger 4 and the first on-off valve of the first refrigeration cycle unit l-A! A bypass circuit 19 is provided that guides the refrigerant from between the refrigerant 3 and the accumulator 12 of the first refrigeration cycle unit A through the second on-off valve 18 and the accumulator type heat transfer device 17 of the second refrigeration cycle unit A2. During the cooling operation of the first refrigeration cycle unit AI, when there is a demand for the compression la2 of the first refrigeration cycle unit A1 or higher, the first on-off valve 13 is closed and the second on-off valve 18 is closed. Open,
The accumulator type heat transfer device W117 is configured to transfer heat between systems. In addition, each indoor unit B
is equipped with an indoor heat exchanger 10 and an expansion mechanism 11, which are connected to the outdoor unit A through refrigerant piping.

Next, the operation will be explained.

The four-way valve 3 is switched between heating operation and cooling operation, the flow of the refrigerant is reversed, and each room in which the indoor unit B is arranged is heated and cooled. At that time, during normal cooling operation of the first refrigeration cycle unit A, the refrigerant discharged from the compression Ia2 is sequentially transferred to the four-way valve 3, the outdoor heat exchanger 4. First on-off valve 13. Accumulator 12. Through the expansion mechanism 11 and the indoor heat exchanger IO, the four-way valve 3. Accumulator 12
, compressor 2 in this order. Figure 2 shows a solinir diagram of this refrigerant circuit, showing the refrigerant pressure P (kg/am2) and enthalpy H (k
cal/kg). c- in this figure 2
This shows that the enthalpy difference between d and f is the same, and this is an effect obtained by exchanging heat between high and low pressures in the accumulator 12. The enthalpy difference used in !!I!34) is the enthalpy difference between e and f.

Here, the first refrigeration cycle unit A.

During cooling operation, when the cooling load increases on the indoor unit B side and the capacity of the compressor 2 becomes insufficient, that is, when there is a request for a capacity exceeding the maximum capacity of the compressor 2, when the capacity of the compressor 2 exceeds the maximum capacity. The opening/closing valve 13 is closed and the second opening FA'#-18 is opened, and the auxiliary second refrigeration cycle unit A2 is operated. As a result, the refrigerant that has passed through the outdoor heat exchanger 4 is guided to the accumulator type heat transfer device 17, where heat transfer between the two systems is performed and then guided to the indoor unit B. That is, the first
The high-pressure liquid refrigerant in the refrigerant piping of the second refrigeration cycle unit A1 during cooling operation passes through the heat transfer device 17 of the second refrigeration cycle unit A2 in a heat-exchanging manner, and is then returned to the optical refrigeration cycle, and is returned to the evaporator ( It is circulated to the outdoor heat exchanger 4). For this reason, a large amount of subcooling is achieved, and a large enthalpy difference between the entrance and exit of the evaporator, which is used for cooling capacity, is set, and the cooling capacity is greatly increased.

Fig. 3 shows Mollier diagrams during operation of the auxiliary refrigeration cycle, in which Fig. 3(a) shows the movement of the first refrigeration cycle unit A, and Fig. 3(b) shows the movement of the second refrigeration cycle. The movements of unit A2 are shown respectively. As shown in Fig. 3, inter-system heat transfer occurs between the refrigerant on the high pressure side between c and d and the refrigerant on the low pressure side between d' and a' of the auxiliary refrigeration cycle. The usable enthalpy difference is the enthalpy difference between e and f (f=a), and a significant increase in cooling capacity can be expected. In addition, the indoor heat exchanger 10
The refrigerant at point d, which is transported to the expansion mechanism 1, is a liquid refrigerant with a large subcool.
1 through which the refrigerant is smoothly distributed to each indoor heat exchanger lO.

In this way, heat exchange is performed between the crystalline pressure liquid refrigerant in the first refrigeration cycle and the low-pressure two-phase refrigerant in the auxiliary second refrigeration cycle. ) can be used to improve the efficiency of the refrigeration cycle.

〔Effect of the invention〕

As described above, according to the present invention, the first on-off valve is provided on the downstream side of the outdoor heat exchanger of the first refrigeration cycle, and the first on-off valve is provided between the outdoor heat exchanger and the first on-off valve. A bypass circuit is provided to guide the refrigerant to the accumulator of the first refrigeration cycle through the on-off valve of 2 and the accumulator type heat transfer device of the second refrigeration cycle, and the compression of the refrigeration cycle of 's1 is performed during the cooling operation of the first refrigeration cycle. When a demand exceeds the capacity of the machine, the first on-off valve is closed and the second on-off valve is opened to transfer heat between systems using the accumulator type heat transfer device, improving the efficiency of the refrigeration cycle. However, there is an effect that the cooling capacity during cooling operation can be significantly increased.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a solenoid diagram of the refrigerant circuit shown in Fig. 1 during normal cooling operation, and Fig. 3 (a). , (b) is a Mollier diagram of the refrigerant circuit shown in FIG. A -------Outdoor unit A, -----・First refrigeration cycle unit A, --
--- Second refrigeration cycle unit B --- One indoor unit 2 --- Compressor 3 --- Four-way valve 4 --- Outdoor heat exchanger! 0...-Indoor heat exchanger 11--Expansion mechanism 12...Accumulator 13--First on-off valve 14--Compressor 15--Condenser 1 .6-... Parking mechanism 17... Accumulator type heat transfer device 18-
. . . Second on-off valve 19 --- Bypass circuit Note that the same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] A first refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, and an accumulator are sequentially connected by refrigerant piping, a compressor,
A control device for a refrigeration machine equipped with two systems of refrigeration cycles, a second refrigeration cycle in which a condenser, an expansion mechanism, and an accumulator type heat transfer device are sequentially connected by refrigerant piping, the controller controlling the outdoor heat of the first refrigeration cycle. A first on-off valve is provided on the downstream side of the exchanger, and a second on-off valve is provided between the outdoor heat exchanger and the first on-off valve through the second on-off valve and the accumulator type heat transfer device of the second refrigeration cycle. A bypass circuit is provided to guide the refrigerant to the accumulator of the first refrigeration cycle, and when the demand exceeds the capacity of the compressor of the first refrigeration cycle during cooling operation of the first refrigeration cycle, the first on-off valve is turned on. A control device for a refrigeration machine, characterized in that the accumulator-type heat transfer device transfers heat between systems by closing the first on-off valve and opening a second on-off valve.