JPS60111852A - 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 [Techniques of the invention also fall into 11 fields] The invention relates to refrigeration cycles in air conditioners, refrigeration units, refrigeration equipment, etc.

[Prior art and seven problems]

Normally, an air conditioner is selected that has the ability to perform sufficient air conditioning at a load close to the maximum load. is very small, and most of the time the vehicle is operated at an outside temperature below this temperature. Figure 1 shows the relationship between outside air temperature and cooling load when keeping the room temperature constant. A1 is the cooling load when the outside temperature is 35°C, and the average outside temperature during the cooling period (this 11 PIJ is 29°C). Assuming the cooling load k A 2 at , A2 is usually less than half of that of AI, and an air conditioner with the capacity of AI often has an excessive capacity for most of the cooling period. Therefore, conventionally, the room temperature is detected by a thermostat, and the compressor'z ON-OFF is controlled based on the detected signal to prevent the room temperature from dropping too much. Figure W, 2 shows the relationship between room temperature and time in this conventional device.

In Figure 2, the line down to the right indicates that the air conditioner is in operation (compressor is in operation), and the double line on the right indicates that the air conditioner is not in operation (compressor is in operation). The case of 4 degrees Celsius is shown. In this case, the compressor is stopped when the room temperature drops to 25 degrees Celsius, and then the room temperature rises due to the cooling load, and when it reaches 29 degrees Celsius, the cooling operation is restarted. Green E is Thermostat setting f is 2
The case is shown in which the thermodynamics was completed at 7°C and the temperature was changed to 1°C. In this case, the room temperature goes back and forth between 26.5°C and 27.5°C, but the number of times the pressure & i machine starts and stops is four times that of the line.

The comfortable temperature range is said to be approximately between 18℃ and 28℃, so 27D is the uncomfortable zone (the extra line in the diagram)
Therefore, in many cases, the setting sensitivity of the thermostat is lowered to 26°C. , Figure 3 shows the relationship between room temperature and cooling load under a constant outside temperature.
When the temperature is changed from MB to 26℃, the cooling load increases from MB to M171.
0, and the compressor operating time ratio increases accordingly. Line F of 2nd line 1 (is thermostat setting 1st shift is 26
℃、Thermodynamics 4 degrees、Case is shown. In the case of line F, the operating time is longer than in the case of line F, and the energy consumption of the air conditioner increases.

As mentioned above, in order to achieve comfortable and energy-saving operation, it is important to reduce the thermodifferential.

There are two important obstacles when trying to reduce the size of thermodynamics. The first problem is restarting the compressor. In other words, immediately after the compressor is stopped, its discharge pipe is at high pressure and its suction pipe is at low pressure, and after the compressor is stopped, refrigerant flows from the high pressure side to the 1°C pressure side through the throttle bones in the refrigerant circuit. This equalizes the pressure. However, if the thermo-differential is made smaller, the start/stop interval becomes shorter, so it is necessary to ensure that the pressure on the discharge and suction sides of the compressor is equalized within a certain period of time (approximately 3 minutes). . If the pressure is not equalized, the compressor will start against the differential pressure, causing startup failure and possibly failing to restart.

The second problem is the heat loss caused by compression-like start and stop.

Figure 4 shows one row of the refrigerant circuit of an air conditioner. During cooling, the high-temperature, high-pressure gaseous refrigerant that exits the compressor 1 passes through the four-way switching valve 2, as shown by the solid arrow, and goes outside. heat exchanger 3
Then, it condenses to become a high-temperature, high-pressure liquid, and when it passes through the throttle 4, it is depressurized and becomes a low-temperature, low-pressure liquid, which enters the indoor heat exchanger 5 and evaporates there. This heat of evaporation cools the indoor air for air conditioning. Further, the refrigerant evaporated and vaporized in the indoor heat exchanger 5 passes through the Achiemure Taro and is sucked into the compressor 1 again.

During heating, the refrigerant flows as shown by the dotted arrow. Now, assume that the compressor 1 is stopped during this cooling operation.
Since there are two states: a low pressure side and a high temperature/high pressure side including the outdoor heat exchanger 3, the refrigerant on the high pressure side flows into the low pressure side through the throttle 4. Therefore, the pressure and temperature on the low-pressure side rise, and the pressure and temperature on the high-pressure side fall. This movement of the refrigerant continues until the pressures on the high pressure side and the substitute pressure side reach palanne.

However, it has become clear that the conventional air conditioner described above suffers the following losses after undergoing the above process. That is, the refrigerant sealed in the refrigeration cycle is
Most of the refrigerant exists in the cycle as a liquid refrigerant [7], and during steady operation, most of it exists in the condenser (in outdoor heat exchanger 3 during cooling), especially in the area from the center of the condenser to the throttle 4. It exists as a liquid refrigerant in the pipes.

When the compressor 1 is stopped, the liquid refrigerant in the condenser (outdoor heat exchanger 3 during cooling) passes through the throttle 4 and flows to the evaporator (indoor heat exchanger 5 during cooling). Most of the liquid refrigerant will be present in a concentrated manner.If the compressor is restarted in such a refrigerant distribution state, most of the liquid refrigerant in the evaporator will flow into the accumulator 6 and condense,
Since there is not enough liquid refrigerant in the rice bowl, the amount of refrigerant supplied to the evaporator through the throttle 4 is extremely small. As a result, there is no liquid refrigerant to evaporate in the evaporator, and even when the compressor is started, the temperature of the blown air does not come down easily, and it takes 2 to 3 minutes for the cold air to blow out. There was a bad air conditioner.

FIG. 5 shows an experimental series of changes in the air conditioner suction temperature, outlet temperature, and temperature at the center of the evaporator when the compressor 1 is restarted during cooling operation in such a conventional series. In the figure, G indicates the intake air temperature of the air conditioner, H indicates the outlet air temperature of the air conditioner, and ■ indicates the total temperature at the center of the evaporator (indoor heat exchanger 5). When the compressor 1 is restarted, the pressure inside the evaporator decreases, so the temperature of the evaporator once decreases, but since liquid refrigerant is not supplied from the condenser through the throttle 4, it is heated by the suction air and rises. The figure shows a phenomenon in which the value decreases after that. For this reason, the blowing temperature H does not slow down and it takes 2 to 3 minutes for the cold air to steadily blow out.

The above heat loss increases as the number of times the compressor starts and stops increases, and becomes a cause of a significant decrease in the annual energy efficiency of the air conditioner.

The above is the same even during heating, although the flow of the refrigerant is different and the temperature and pressure are reversed.0 [Object of the Invention] The invention was made in view of the above points, In a refrigeration cycle equipped with a refrigerant circuit that circulates through a condenser, a throttle, and an evaporator in this order, a refrigerant storage container is connected via a connecting pipe to an appropriate position of the refrigerant circuit that includes the ridge and reaches the evaporator. In addition, total heat is exchanged between the refrigerant storage container and the suction pipe of the compressor, and a valve that opens and closes in response to the start and stop of the compressor is provided in the connecting pipe, thereby reducing heat loss by 2. At the same time, it is important to provide a refrigeration cycle in which no pressure difference occurs between the compressor discharge pipe and the suction pipe when the compressor is restarted.

[Practice of the invention! /! l) The details of the invention will be explained below with reference to the embodiment diagram 11 shown in FIG. In Fig. 6, 11 is a compressor, 12 is a four-way switching valve, 13 is an outdoor heat exchanger, 14 is a throttle, I5 is an indoor heat exchanger, 16 is an accumulator, Noah is a refrigerant storage container, and 18 is a refrigerant storage A connecting pipe 19 connects the container J7 and the refrigerant circuit, 19 is an on-off valve installed in the connecting pipe 8, and 20 is a refrigerant pipe exchanging heat with the refrigerant storage container 17.

In the present invention, the refrigerant storage container 17 is the refrigerant distribution container of the compressor 11.
It is arranged so as to exchange heat with 20. Further, the container 17 is connected to a refrigerant circuit by a connecting pipe 18. The connecting point is connected to an appropriate position of the piping including the entire throttle 14 and leading to the evaporator. In this case, the evaporator is
It corresponds to the indoor heat exchanger 15 during cooling operation, and corresponds to the outdoor heat exchanger 13 during heating operation. Furthermore, an on-off valve 19 is installed in the connecting pipe 18, and this on-off valve 19 opens when the compressor 11 is started and closes when the compressor 11'j is stopped.

Next, the operation of the above implementation column will be explained. 11 when cooling
As indicated by the solid line, the high-temperature, high-pressure gaseous refrigerant from the compressor 11'z passes through the four-way switching valve 12 and undergoes heat exchange on the outdoor side.
'L l 3 condenses and becomes a high temperature and high pressure liquid.
4F, 7, the pressure is reduced and the liquid becomes a low temperature and low pressure liquid, which is transferred to the indoor heat exchanger 15 and evaporated there. This heat of evaporation cools the indoor air and performs Q). Further, the refrigerant evaporated and vaporized in the indoor heat exchanger 15 passes through the four-way switching valve 2, the piping 2o, and the accumulator 16, and is sucked into the compressor 1 again.

Further, the pressure inside the refrigerant storage container 17 corresponds to the connection point between the connecting pipe 18 and the refrigerant circuit (point J in Figure 6). When the compressor 1 is operating in a steady state, the pressure at the 5 points is an intermediate pressure obtained by adding the pressure loss due to the flow of refrigerant from the suction pressure (low pressure) of the compressor 1.

Therefore, the on-off valve 19 is open in the refrigerant storage container lZ, and refrigerant gas in an intermediate pressure state comes into the refrigerant storage container lZ.On the other hand, the container 17 is cooled by the pipe 2θ through which low-temperature, low-pressure refrigerant flows. has been done. Therefore, the refrigerant in the refrigerant storage container 17 is cooled and condensed, and the liquid refrigerant at the intermediate pressure 7 is stored.

Now, if the compressor 1 is stopped during this cooling operation, the on-off valve 1d is closed and intermediate-pressure liquid refrigerant is confined in the refrigerant storage container 17. The refrigerant circuit connects the indoor heat exchanger 1 with the aperture I4 and the compressor 1 as boundaries.
Since the refrigerant on the high pressure side passes through the 14 throttles and flows into the low pressure side, the refrigerant flows into the low pressure side through the 14 throttles. This movement of the refrigerant continues until the pressures on the high-pressure side and the low-pressure side are balanced, and the pressures are reliably equalized.

Next, if the compressor 1 is restarted, the pressure in the discharge pipe and suction pipe of the compressor 1 is equalized by the movement of the refrigerant through the throttle 14 during the stop, so that the restart can be ensured. Simultaneously with starting the compressor I, the on-off valve 19 is opened. Immediately after startup, the suction pressure (low pressure) of the compressor 11 is lower than during steady operation, and the amount of refrigerant circulation is also small, so the pressure loss due to the flow of refrigerant is also smaller than during steady operation. The pressure at the connection point (point 5) between compressor I and the refrigerant circuit is
Immediately after J starts up, it is lower than during normal operation. The liquid refrigerant in the refrigerant storage vessel lz is therefore forced into the refrigerant circuit and is fed through a portion of the throttle 14 to the indoor heat exchanger 15 acting as an evaporator, where it is evaporated. Even immediately after starting the compressor 11, refrigerant is supplied to the evaporator and cold air is quickly blown out.

As the operation continues further and becomes steady operation, the amount of refrigerant circulation increases, and the intermediate pressure liquid refrigerant accumulates in the refrigerant storage container 17 again as described above.

The above explanation has been about cooling operation, but during heating, the flow of refrigerant is as shown by the dotted arrow, and the indoor heat exchanger 15 operates as a condenser and the outdoor heat exchanger 13 operates as an evaporator.
Other effects are the same as during cooling.

[Effects of the Invention] As described above, in the present invention, the refrigerant storage container 17f is provided, and during steady operation of the compressor 11, all of the liquid refrigerant in an intermediate pressure state is stored in the container J7, and the on-off valve 19f is kept open even when the compressor is stopped. This state is maintained by closing. The pressure balance between the discharge side and the suction side of the compressor 1 when the compressor is stopped is equalized by the throttle 14 so that no pressure difference occurs when the compressor is restarted. When restarting the compressor, the liquid refrigerant in the container is pushed out into the refrigerant circuit by fully opening the on-off valve 19, taking full advantage of the fact that the pressure at the connection point between the refrigerant storage tea appliance 17 and the refrigerant circuit is lower than the steady state. Liquid refrigerant is supplied to the evaporator immediately after startup. Therefore, this liquid refrigerant is evaporated in the evaporator, and the start-up performance can be improved. This makes it possible to realize an air conditioner with good annual energy efficiency even if the number of times the compressor starts and stops increases.

In addition, in the above description, we have discussed the case where the method is applied to an air conditioner, but the arrangement can also be implemented in the same way in other refrigerators, refrigeration equipment, etc.

[Brief explanation of the drawing]

Figures 1, 2, 3, and 5 are diagrams showing the operating characteristics of a conventional air conditioner, Figure 4 is a diagram showing a refrigerant circuit of a conventional air conditioner, and Figure 6N is a diagram showing the refrigerant circuit of a conventional air conditioner. It is a refrigerant circuit diagram showing one example. 11... Compressor, 12... Four-way switching valve, 13...
Outdoor heat exchanger, 14... Throttle, 15... Indoor heat exchanger, 16... Achimulator, 17... Refrigerant storage container, 1B... Connection pipe, 19... Open/close valve , 20・
・Refrigerant piping.

Claims (1)

[Claims] In a refrigeration cycle equipped with a refrigerant circuit in which refrigerant circulates through a compressor, a condenser, an aperture, and an evaporator in this order, the refrigerant is passed through a connecting pipe to an appropriate position in the refrigerant circuit that includes the aperture and reaches the evaporator. It is particularly preferable that the storage tea utensils are connected to exchange total heat with the refrigerant storage container and the suction pipe of the compressor, and a valve is provided in the connection to open and close in response to starting and stopping of the compressor. refrigeration cycle.