JPS59191849A - Method of controlling refrigeration cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for controlling a refrigeration cycle, and in particular to a gas injection type refrigeration system in which gas refrigerant is injected into a compressor among the gas-liquid mixed refrigerant generated during depressurization of the refrigeration cycle. Concerning a cycle control method.

[Technical background and problems of the invention]

BACKGROUND ART In recent years, heat pump type air conditioners, which can perform cooling operation and heating operation simply by switching a switch, have been increasingly used. Japan's general climate (for example, 0°C in winter, 30°C in summer)
℃), the cooling/heating capacity ratio is about 1.5 if the cooling capacity is 1. However, when a compressor whose capacity is not variable is used, the above-mentioned cooling/heating capacity ratio is generally only about 1.2 for the cooling capacity due to the refrigeration cycle design, which means that the compressor capacity is not equal to the cooling capacity. If combined, the heating capacity will be insufficient. On the other hand, if the capacity of the pressure QIt machine is adjusted to the capacity of the room, the capacity of the compressor will increase too much during the cooling operation, resulting in over-cooling, which not only has a negative effect on the body, but also causes power loss due to the 0N-OFF operation. , at startup due to sudden 0N-OFF action? JjljA has disadvantages such as reduced durability of the compressor.

In addition, many devices conventionally use auxiliary electric heating devices to compensate for the lack of heating capacity. In this case, a relatively small-capacity compressor is sufficient, so there is no problem with efficiency during cooling, but when heating, the input and current increase due to the auxiliary electric heating device, making it necessary to increase the power supply capacity, and safety devices are not included. There are many parts that need to be connected, and it is inevitable that the equipment will become larger. It looks even more thermally efficient (j
If the value of 1 auxiliary electric heating device is 1, then that of the refrigeration cycle is 2 to 2.5, and the use of the auxiliary electric heating device during heating is also poorer in terms of thermal efficiency than that of the refrigeration cycle. Therefore, in order to increase the heating capacity, it may be possible to adopt a gas injection method in which the gas refrigerant separated by the gas-liquid separator during heating is introduced into the cylinder during the compression stroke of the compressor. However, according to the above-mentioned waste injection method, the refrigerant waste separated by the gas-liquid separator is used even though there is no need to increase the frozen egg power for heating or cooling during heating overload or cooling operation when the outside temperature is high. inject into the compressor,
As a result, the room temperature quickly reaches the specified base temperature and the number of times the compressor turns on and off increases, resulting in increased noise during startup, power loss during startup, and reduced compressor durability. A close encounter occurred.

In particular, in the waste injection type refrigeration cycle, since the compressor has a small capacity, there is a drawback that when heating is overloaded, the discharge temperature of the compressor rises, causing the compressor motor to overheat and burn out the motor coil. there were.

In other words, in the conventional gas injection type refrigeration cycle, the liquid mixed refrigerant generated during the depressurization of the refrigeration cycle is simply injected into the compressor, regardless of the load, and has the above-mentioned drawbacks. .

[Purpose of the invention]

The entire purpose of the present invention is to provide a control method for completely activating or inactivating the dregs injection of a dregs injection type Reishin cycle in which dregs refrigerant of the gas-liquid mixed refrigerant generated during depressurization of the refrigeration cycle is injected into the compressor. .

[Summary of the invention]

This invention utilizes a control method in which gas-liquid mixed refrigerant generated during depressurization of the refrigeration cycle is injected or not injected into the compressor, so that the gas injection is fully activated or deactivated to increase or decrease the refrigerating capacity. It is variably controlled.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to all the drawings. Figure 1 shows the entire configuration of the refrigeration cycle, where 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a check valve, 5 is a gas-liquid separator, and 6 is a pressure reducer. Capillary tubes 7, which are devices, are indoor heat exchangers, and these are connected via refrigerant pipes in the above-mentioned numerical order to constitute a heat pump type refrigeration cycle. Further, a branching device 8 is provided between the check valve 4 and the gas-liquid separator 5, and this first
The branch port 83 is provided with a conduit pipe 10 that is branched from between the outdoor heat exchanger 3 and the check valve 4 and has an auxiliary expansion valve 9 in the middle. Furthermore, the second branch port 8b of the branching tool 8 is provided with a gas injection circuit 11, which will be described later. No, this waste injection circuit] 1 is connected to the branch port 8bK at one end, and is equipped with a heat sensing part 12a that senses the temperature on the discharge side of the compressor during heating operation in the middle part, and when the temperature exceeds a predetermined temperature. A waste injection pipe 1 is provided with an on-off valve 12 that closes when the sensor senses the engine and opens normally, and the other end communicates with the compressor 10 and the cylinder shown in the figure.
Consists of 3.

Next, the operation of the IF in the above embodiment will be explained. First, to explain the cooling operation, since cooling does not require as much capacity as heating, the on-off valve 12 is closed and the gas injection valve is inactive. That is, the refrigerant discharged from the compressor 1 is guided to the outdoor heat exchanger 3 through the four-way valve 2, as shown by the broken line arrow in the figure, and is condensed and liquefied.

Furthermore, a check valve 4, a gas-liquid separator 5, a capillary tube 6
The latent heat of evaporation from the air-conditioned room is guided to the indoor heat exchanger 7 via the It can be taken away to perform a cooling effect. 'Next, heating operation will be explained. When the outside temperature is low and the heating load is low, it is necessary to fully increase the refrigeration capacity for heating, and the on-off valve 12
Open it and let the cass injection work fully. That is, during heating overload, the refrigerant discharged from the compressor 1 is guided to the indoor heat exchanger 7 through the four-way valve 2, as shown by the solid line arrow in the figure, and the condensed heat is released into the air-conditioned room to be used for heating. What you do is what you do. The condensed and liquefied refrigerant is depressurized by a capillary tube 6 and an auxiliary expansion valve 9 at a pressure reduction ring 1, and the gas-liquid mixed refrigerant generated during depressurization is separated into a waste refrigerant and a liquid refrigerant by a gas-liquid separator 5. After separation, the liquid refrigerant is guided from the branching device 8 to the conduit pipe 10, further expanded by the auxiliary expansion valve 9, evaporated by the outdoor heat exchanger 3, and sucked into the compressor 1.

On the other hand, the gas refrigerant separated by the gas-liquid separator 5 is led to the waste injection circuit 1, and is sucked into the cylinder of the compressor 1 during the compression process via the on-off valve 12, thereby performing a waste injection action.

The entire refrigeration cycle in this state.To explain from the Mollier diagram shown in Figure 2, the refrigerant is separated into liquid and waste at point E (F
The point indicates the liquid and the point H indicates the gas refrigerant), and the liquid refrigerant #: further expands and evaporates into the compressor 1.
In the end, the conditions are the same as supercooling to point C. Furthermore, when the compressor completes suction and enters the compression stroke, the waste refrigerant separated at point E is introduced into the cylinder and compressed to point B. As a result, the amount of refrigerant discharged from the compressor 1 is the sum of the amount of refrigerant sucked in at point A and the amount of refrigerant sucked in during the compression stroke.

Therefore, the refrigerating capacity is improved by the amount of enthalpy between the point in the figure and the point G (in other words, by the amount by which the amount of discharged refrigerant is increased) compared to a refrigeration cycle not equipped with the cass injection circuit 11, and the heating efficiency is improved.

The enthalpy of the refrigerant entering the converter 3 is reduced and the compressor 1
Refrigerant is injected into the compressor 1 to increase the discharge refrigerant flow rate to increase the refrigerating capacity, but since the suction pressure of the refrigerant gas injected into the compressor 1 is high, the increase in compression work is small and the input does not increase much, so the efficiency is low. It's good.

Also, during heating operation, if the outside temperature is high and the operation is overloaded, there is no need to fully increase the refrigerating capacity to perform heating, so the on-off valve 12 is closed and the gas separated by the gas-liquid separator 5 is compressed. Prevent machine 1 conduction.

Therefore, from the 6 points shown in FIG. 2, the refrigerant changes isenthalpically and reaches point D, where it evaporates while still containing part of the waste refrigerant. In other words, it is not a gas injection cycle, and the compressor 1
It can be shown that the human power is reduced and heating can be performed in the optimum condition.

〔Effect of the invention〕

As explained above, in this invention, by controlling the gas-liquid mixed refrigerant generated during the depressurization of the refrigeration cycle to be injected or not injected into the gas refrigerant total compressor, dregs injection is activated or deactivated to achieve the full refrigeration capacity. This has the effect that the refrigeration cycle can be controlled according to the load by increasing or decreasing the load.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG.
The configuration diagram of the refrigeration cycle, FIG. 2, is a Mollier diagram. ]...Compressor, 3...Outdoor heat exchanger, 5...
Gas-liquid separator, 6...pressure reducing device, 11.Φ.Cass injection circuit Patent attorney Kensuke Norichika (and others) Fig. 1 Fig. 2

Claims (1)

[Claims] A method for controlling a refrigeration cycle, characterized in that the capacity of the refrigeration cycle is varied by injecting or not injecting gas refrigerant among the gas-liquid mixed refrigerant generated during depressurization of the refrigeration cycle into a compressor.