JPS60211271A - 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 refrigeration cycle in an air conditioner, a refrigerator, a refrigeration device, etc.

[Prior art and its problems]

Normally, an air conditioner is selected that has the ability to perform sufficient air conditioning at a load close to the maximum load. Most of the time, the vehicle is operated at ambient temperatures below that temperature. Figure 1 shows the relationship between outside air temperature and cooling load when keeping the room temperature constant. AI is the cooling load when the outside temperature is 35°C, and the average outside temperature during the cooling period (in this example, it is 29°C). The cooling load in A2
Then, A2 is A.

Compared to J), which is usually less than half as busy, an air conditioner with AI capabilities will last most of the cooling period! He will have great abilities. Therefore, conventionally, the room temperature is detected by a thermostat, and the compressor is controlled ON-OFF based on the signal to prevent the room temperature from dropping too much. FIG. 2 shows the relationship between room temperature and time in this conventional device.

In FIG. 2, the lower right line indicates cooling operation (compressor operation), and the upper right line indicates cooling operation is stopped (compressor is stopped). The line shows the case where the setting value of Su-Mosta is 27 degrees Celsius and the thermodifferential is 4 deg degrees Celsius. In this case, the compressor is stopped when the room temperature drops to 25°C, and then the room temperature rises due to the cooling load, and when the room temperature reaches 29°C, the cooling operation is resumed. Line E indicates the thermostat setting is 27.
℃ and the thermodifferential is set to 1℃. In this case, the room temperature fluctuates between 26.5°C and 27.5°C, but the number of times the compressor starts and stops is four times that of the wire.

The comfortable temperature range is said to be approximately between 18°C and 28°C, so the line has an uncomfortable zone (the shaded area in the diagram), so in many cases the thermostat setting is set to 26°C, for example. be lowered to Figure 3 shows the relationship between the cooling load and the room temperature under a constant outside temperature.When the thermostat setting is changed from 27℃ to 26℃, the cooling load increases from line B to line C. The compressor operating time ratio increases accordingly. Line F in Figure 2 indicates that the thermostat setting is 26℃ and the thermodifferential is 4d.
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, it is important to reduce the thermodifferential in order to achieve comfortable and energy-saving operation.

There are two important obstacles to reducing thermodifferentials: 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.After the compressor is stopped, refrigerant flows from the high-pressure side to the low-pressure side through the throttle pipe section in the refrigerant circuit. This equalizes the pressure. However, if the thermodifferential is made smaller, the start/stop interval becomes shorter, so it is necessary to ensure that the pressures on the discharge side and the suction side of the compressor are equalized within a predetermined time (about 3 minutes). If the pressure is not equalized, the compressor will not be able to start against the differential pressure, resulting in startup failure and failure to restart.

The second problem is heat loss due to the start and stop of the compressor.

Fig. 4 shows an example of the refrigerant circuit of an air conditioner. During cooling, the high temperature and high pressure refrigerant in the form of a sluice exits the compressor 1 as shown by the solid line arrow, and flows through the four-way switching valve 2. , outdoor heat exchanger 3
Then, it condenses to become a high-temperature, high-pressure liquid, and when it passes through constrictor #4, it is depressurized and becomes a low-temperature, low-pressure liquid, and enters the indoor heat exchanger 5 where it evaporates. 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 accumulator 6 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. With the restrictor 4 and compressor 1 as boundaries, there are two states: a low temperature/low pressure side including the indoor heat exchanger 5 and a high temperature/high pressure side including the outdoor heat exchanger 3. The refrigerant on the side flows into the low pressure side. Therefore, the pressure and temperature on the low-pressure side rise, and the pressure and temperature on the high-pressure side fall. This refrigerant movement is
The high pressure side and the low pressure side continue until the pressure reaches the f lance.

However, it has become clear that the conventional air conditioner described above suffers the following losses after undergoing the process described above. In other words, the refrigerant sealed in the refrigeration cycle is
Most of the refrigerant exists in the cycle as liquid refrigerant, and during steady operation, most of the refrigerant exists concentrated in the condenser (in outdoor heat exchanger 3 during cooling), especially when it reaches the throttle 4 from the center of the condenser. 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) flows through the throttle 4 to the evaporator (indoor heat exchanger 5 during cooling). Most of the liquid refrigerant will be present in a concentrated manner. When the compressor 1 is restarted in such a refrigerant distribution state, most of the liquid refrigerant in the evaporator flows into the accumulator 6, and since there is not enough liquid refrigerant in the condenser, the evaporator The amount of refrigerant supplied through the throttling tube 4 becomes extremely small. As a result, there is no liquid refrigerant to be evaporated in the evaporator, and the compressor 1
Even when the air conditioner was started, the temperature of the blown air did not come down easily, and it took 2 to 3 minutes to blow out cold air, resulting in an air conditioner that was slow to start up.

FIG. 5 shows an experimental example of changes in the suction temperature of the air conditioner, the quality of the air outlet 1', and the temperature at the center of the evaporator when the compressor 1 is restarted during cooling operation in such a conventional example. In the figure, G indicates the intake air temperature of the air conditioner, ■ indicates the outlet air temperature of the air conditioner, and ■ indicates the 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 decrease easily, and the result shows that it takes 2 to 3 minutes before the cold air is blown out steadily.

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.

In the same way, the refrigerant flow is different even during heating, and the temperature and pressure levels are reversed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned points, and provides a refrigeration cycle in which a compressor, a four-way valve, an evaporator, a condenser, and a throttle are sequentially connected. A valve is installed to prevent the flow of refrigerant to the compressor when the compressor is stopped, and a valve is installed between the discharge piping between the valve and the compressor and the suction piping of the compressor for starting and stopping the compressor. In addition, a valve that opens and closes according to the pressure difference between the high-pressure side pressure and the low-pressure side pressure is installed between the condenser and the piping including the restrictor, and heat generated when the compressor starts and stops. It is an object of the present invention to provide a refrigeration cycle that reduces loss and reliably prevents a pressure difference between a compressor discharge pipe and a suction pipe when the compressor is restarted.

[Embodiments of the invention]

The details of the present invention will be explained below with reference to the embodiment shown in FIG. In Fig. 6, 1 is a compressor, 12 is a four-way switching valve, 13 is an outdoor heat exchanger, 14 is an indoor heat exchanger, 1
5 is an accumulator, 16.17 is a capillary tube, 18.19
．． 20.21゜22 is the check valve, 23 is the compressor "J'J"
24 is a pressure equalization pipe, 25 is a suction pipe of compressor 1,
26 is an on-off valve, 27, 28, 29 is a pipe, 3° is a pressure difference on-off valve (pal 7"), 31 is a main body of the valve, 32 is an upper cover of the valve, 33 is a diaphragm, and 34 is a valve attached to the diaphragm. Gold shaft, 35 is a ball, 36 is a leaf spring, 37 is a valve seat, 38 is a valve inlet pipe, 39 is a valve outlet pipe,
40 is a pressure introduction pipe for transmitting a pressure signal to the valve.

Therefore, the pressure difference on/off valve 3θ has a high pressure side 30 m and a low pressure side 30 m inside the valve with the diaphragm 33 as a boundary.
It is divided into b. The low pressure side is partitioned by an upper lid 32 and communicated with a pressure introduction pipe 40. diaphragm 3
A shaft 34 is attached to the lower surface of the shaft 3, and a ball 35 is welded to the tip thereof. A plate spring 3 is provided between the shaft 34 and the valve body 31! is inserted.

A valve seat 37 is provided at the bottom of the pulp body 31, and when the pulp 19 ball 35 hits the valve seat 37, the flow is interrupted. An inlet pipe 38 and an outlet pipe 39 are attached to the valve body 3.

Next, the operation of the above embodiment will be explained. First, the operation of the pressure difference on/off valve 300 will be explained. The high pressure chamber 30a below the diaphragm 33 is constantly in communication with the inlet pipe 38, and inlet pressure (Pl) acts thereon, which is the force that tends to open the valve. On the other hand, the low pressure chamber sob above the diaphragm 33
The introduction pressure (P2) from the pressure introduction pipe 40 is acting on the pressure introduction pipe 40. Furthermore, the diaphragm 33 is operated by the leaf spring 36,
It is receiving spring force (F). Therefore, the force for closing the valve is the combined value of the introduction pressure (P2) and the spring force (F).

On the other hand, since the Paneka (F) is preset to a predetermined value, when the pressure amount (ΔP) of the inlet pressure (Pl) and the introduction pressure (P2) becomes larger than the predetermined value (P8), the valve opens; When the pressure difference (ΔP) becomes smaller than a predetermined value CP, . . . , the valve closes.

Next, the operation of the refrigerant circuit will be explained. The on-off valve 26 is closed when the compressor 11 is in operation, and is opened when the compressor 11 is stopped. In addition, the refrigerant circulates as shown by the solid arrow (→ mark) during cooling due to the action of the compressor 1, the four-way switching valve 12, the reversing valve 1B, 19, 20° 21, and the dotted arrow (...) during heating.
・・・〉mark) It circulates. During cooling, the high-temperature, high-pressure gaseous refrigerant leaving the compression @ 11 is discharged through the discharge pipe 23 and the check valve 22.
It passes through the four-way switching valve 12 and is condensed and liquefied in the outdoor heat exchanger 13 to become a high-temperature, high-pressure liquid. This high temperature and high pressure i&
The refrigerant passes through the check valve 18, passes through the pipe 28, and reaches the inlet pipe 38 of the pressure on/off valve 3θ, and high pressure is introduced into the inlet pipe 38. At this time, low pressure is introduced to the pressure introduction pipe 40 of the pressure difference on/off valve 30 via the pipe 22. As a result, a pressure difference is created between the inlet pressure (P+) and the introduction pressure (P2), which is higher than the predetermined value (P,), so the pressure difference on/off valve 3
θ is open. Furthermore, the high-temperature, high-pressure liquid refrigerant reaches the capillary tube 16 through the outlet pipe 39, piping 29, and check valve 20, where it is depressurized and expanded under frictional resistance, and becomes a low-temperature, low-pressure liquid refrigerant.

Furthermore, it evaporates and vaporizes in the indoor heat exchanger 14, passes through the four-way switching valve 12 and the accumulator 15, and is compressed and sucked into the pipe 11.

Next, when the operation of the compressor 11 is stopped, the on-off valve 26 is opened, and the pressure in the discharge pipe 23 and suction pipe 25 of the compressor 1) is equalized, and the pressure (P2) in the pressure introduction pipe increases. Ten thousand,
The inlet pressure (Pl) decreases as the compressor 11 stops, and the pressure difference (ΔP) becomes smaller than the predetermined value (P,), so the pressure difference opening/closing valve 30 is closed. FIG. 7 shows the operation of the compressor 1 and the operating characteristics of the pressure differential opening/closing valve 30. In addition, in FIG. 7, (Pl) is the discharge pipe 23 of the compressor 11.
This is the pressure of The above has been explained with reference to cooling operation, but even during heating operation, the flow of refrigerant changes as shown by the dotted arrow (...>), but the operating characteristics of the pressure difference on/off valve 30 and compressor 1 are as shown in Figure 7. are the same.

As described above, in the present invention, since the pressure difference on/off valve 30 is provided in the middle of the pipe line from the condenser outlet to the capillary tube, the sixth
In the case shown in the figure, the outdoor heat exchanger 13 functions as a condenser during cooling, and the pressure is reduced by the capillary tube 16. On the other hand, during heating, the indoor heat exchanger 14 functions as a condenser, and the pressure is reduced by the capillary tube 17. For this reason, when the compressor 11 is stopped, the movement of liquid refrigerant from the condenser to the evaporator via the capillary tube is controlled by the pressure difference opening/closing tPs.
This is prevented by the action of o.

t ft, the pressure is equalized between the discharge 'f123 of the compressor 11 where there is a high-pressure refrigerant in the form of a sliver and the suction pipe 250, and the refrigerant moves from the high-pressure side to the low-pressure side so that it becomes a gaseous refrigerant,
Moreover, the action of the check valve 22 prevents the high-temperature, high-pressure gaseous refrigerant in the condenser from moving to the low-pressure side. As a result of jin,
The amount of refrigerant remaining in the condenser when the compressor 11 is stopped can be significantly increased compared to the conventional example.
Even if the engine is restarted, a large amount of liquid refrigerant can be quickly supplied from the condenser to the evaporator, resulting in good start-up performance. This makes it possible to realize an air conditioner that is energy efficient throughout the year even if the number of times the compressor starts and stops increases.

In addition, the amount of refrigerant present in the evaporator when the compressor 1 is stopped can be significantly reduced compared to the conventional example, so when the compressor 1 is restarted, the compressor is Overload operation can be avoided and the compressor can be started with a light load, and the compressor overload protection device that occurs in the conventional example does not have to operate, allowing smooth operation.

In addition, since the pressures in the discharge pipe 23 and the suction pipe 25 are equalized by the action of the on-off valve 26 when the compressor 11 is stopped, the pressure is reliably balanced in a short time. For this reason, as occurred in the conventional example,
It is possible to eliminate problems such as taking a long time to balance the pressure, which hinders the cooling/heating feeling, and restarting the system even though a pressure difference remains, resulting in startup failure.

Note that the present invention can be implemented in room air conditioners, package air conditioners, chillers, refrigeration devices, and the like.

〔Effect of the invention〕

As detailed above, according to the present invention, a compressor, a four-way valve,
In a refrigeration cycle in which an evaporator, a condenser, and a throttle are connected in sequence, a valve is provided between the compressor and the four-way valve to block the flow of refrigerant toward the compressor at least when the compressor is stopped; A valve that opens and closes in response to starting and stopping the compressor is installed between the discharge piping between the valve and the compressor and the suction piping of the compressor, and a high-pressure side valve is installed between the condenser and the piping containing the throttle valve. The main feature is that a valve is installed that opens and closes depending on the pressure difference between the pressure and the low pressure side pressure, so it reduces heat loss when the compressor starts and stops, and the compressor discharge pipe and suction when restarting the compressor. It is possible to provide a refrigeration cycle that reliably prevents the generation of differential pressure between pipes.

[Brief explanation of drawings]

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 6 is a diagram showing the present invention. FIG. 7 is a refrigerant circuit diagram showing one embodiment of the present invention, and FIG. 7 is a diagram showing the operation characteristics of the compressor and the pressure difference opening/closing valve in the same embodiment. 1... Compressor, 12... Four-way switching valve, 13...
Outdoor heat exchanger, 14... Indoor heat exchanger, 15...
・Accumulator, 16.17...Capillary tube, 18゜1
9.20.21.22...Check valve, 23...Discharge pipe, 24...Pressure equalization pipe, 25...Suction pipe, 26...Opening/closing valve, 27.28.29... Piping, 30... Pressure difference on/off valve, 3... Pulp body, 32... Pulp top cover, 33... Diaphragm, 34... Wetting shaft, 35...
... Ball, 36... Leaf spring, 37... Valve seat, 38...
・Pulp inlet pipe, 39...Pulp outlet pipe, 40・
...Pressure introduction pipe. Applicant Sub-Agent Patent Attorney Takehiko Suzue -I Aji

Claims (1)

[Claims] In a refrigeration cycle in which a compressor, a four-way valve, an evaporator, a condenser, and a throttle are connected in sequence, a valve is provided between the compressor and the four-way valve that blocks refrigerant flow to the compressor side at least when the compressor is stopped. A valve is provided between the discharge piping between the volume valve and the compressor, and a valve that opens and closes in response to starting and stopping the compressor between the discharge piping and the suction piping of the compressor. A refrigeration cycle characterized in that the refrigeration cycle is equipped with a valve that opens and closes depending on the pressure difference between high pressure side pressure and low pressure side pressure.