JPS6240635B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the amount of refrigerant that changes the amount of refrigerant circulating in a refrigerant circuit in response to changes in load, thereby achieving the maximum refrigerating capacity according to the load. be.

Conventionally, a refrigeration system equipped with a refrigerant amount adjustment device connects a compressor a, a condenser b, a throttle device c, and an evaporator d in a ring, and throttles a refrigerant amount adjustment container e, as shown in Fig. 1. At connection position g in the middle of device c,
Alternatively, a configuration is known in which a suction pipe f is connected between the throttle device c and the evaporator d, and further connects the compressor a and the evaporator d, through the refrigerant amount adjustment container e.

In such a configuration, the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjustment container e is in a gas-liquid two-phase saturated state. Therefore, if the suction pipe f does not penetrate the refrigerant amount adjustment container e, the state of the refrigerant inside the refrigerant amount adjustment container e is the same as that of the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjustment container e. Become saturated. However, the suction pipe f is
If the suction pipe f passes through the
Since the temperature is lower than that of , a part of the refrigerant inside the refrigerant amount adjustment container e condenses. Therefore, the wetness of the refrigerant inside the refrigerant amount adjusting container e is greater than the wetness of the refrigerant at the connection position g between the expansion device c and the refrigerant amount adjusting container e. In other words, when the temperature of the suction pipe f is lower than the temperature of the connection position g,
The refrigerant is simply accumulated in the refrigerant amount adjustment container e.

The change in the state of the refrigerant inside the refrigerant amount adjusting container e described above with respect to the load will be explained using FIG. 2.
When considering the heat balance of the refrigerant amount adjustment container e, the main amount of heat is the amount of heat that enters the refrigerant amount adjustment container e due to heat transfer from the air around the refrigerant amount adjustment container e, and the amount of heat that enters the refrigerant amount adjustment container e. There is an amount of heat taken away from the refrigerant amount adjustment container e by the suction pipe f passing through the refrigerant amount adjusting container e. Figure 2 shows the heat balance of the refrigerant amount adjustment container e with respect to load fluctuations of the refrigeration device, with the horizontal axis representing the load on the refrigeration system and the vertical axis representing the amount of heat entering the refrigerant amount adjustment container e. This is what I did. However, the fact that the amount of heat entering is negative means that the amount of heat is taken away from the refrigerant amount adjustment container e. In FIG. 2, a curve q1 represents a change in the amount of heat entering from the surrounding air with respect to the load, and a curve q2 represents a change in the amount of heat entering from the suction pipe f with respect to the load. The total amount of heat that enters the refrigerant amount adjustment container e is the sum of q1 and q2, and this total amount of heat that enters is represented by a curve q3. Here, the point x on the curve q3 means that there is no amount of heat entering the refrigerant amount adjustment container e.

By the way, the case where the refrigerant amount adjusting container e performs the function of adjusting the refrigerant amount is only when the load changes within a certain range around the load represented by the point x. This is because when the load is much larger than the load at point x, the refrigerant amount adjustment container e
The refrigerant inside is always in the state of superheated steam, and even if there is a load change, only the degree of superheating of the refrigerant inside the refrigerant amount adjustment container e changes, and the mass accumulated inside the refrigerant amount adjustment container e There is almost no change in . On the other hand, when the load becomes much smaller than the load at point Only the degree of cooling changes, and there is almost no change in the mass of the refrigerant accumulated inside the refrigerant amount adjustment container e. However, the range of normal loads in which refrigeration equipment is used is
This is the range indicated by point m and point n in FIG. In other words, the normal load range in which the refrigeration system is used is considerably lower than the load represented by point x.

As is clear from the above explanation, in the normal load range in which the refrigeration system is used, the interior of the conventional refrigerant amount adjustment container e is occupied by supercooled liquid, and the refrigerant amount is adjusted only in an extremely large load range. It has the disadvantage that it does not perform the function of regulating the amount of refrigerant within the normal load range in which the refrigeration system is used. Particularly at low loads, the disadvantage was that liquid returned to the compressor.

Therefore, the present invention solves the above-mentioned conventional drawbacks, and enables refrigerant circuits to be used in large load ranges, normal load ranges in which refrigeration equipment is used, as well as low load ranges and load fluctuations in all load ranges. By changing the amount of refrigerant flowing through the system, it is possible to always make the refrigeration system perform at its maximum capacity depending on the load.

An embodiment of the present invention is shown in FIGS. 3, 4 and 5.
This will be explained using figures. As shown in FIG. 3, a compressor 1, a condenser 2, a throttle device 3, and an evaporator 4 are each connected in a ring. A first refrigerant amount adjusting container 5 and a second refrigerant amount adjusting container 6 are connected in the middle of the expansion device 3. Further, the suction pipe 8 connects the compressor 1 and the evaporator 4. Condenser 2 and throttling device 3
A first branch pipe 7a is provided in the connecting pipe 7 that connects the connecting pipe 7, one end of which is connected to a first branch point 7b in the middle of the connecting pipe 7, and the other end of the first branch pipe 7a is In the middle of the connecting pipe 7, the first branch point 7
It is connected to a first merging point 7c located closer to the throttle device 3 than b. Furthermore, as shown in FIG. 4, the suction pipe 8 and the first branch pipe 7a are
They are respectively disposed in the first refrigerant amount regulating container 5 in a heat exchange manner. Further, the suction pipe 8 is provided with a second branch pipe 8a equipped with a first on-off valve 10, one end of which is connected to a second branch point 8b in the middle of the suction pipe 8, and the second branch pipe 8a is provided with a first on-off valve 10. The other end of the pipe 8a is connected to a second confluence point 8c located in the middle of the suction pipe 8 closer to the compressor 1 than the second branch pipe 8b. Further, the discharge pipe 9 connecting the compressor 1 and the condenser 2 is provided with a third branch pipe 9a equipped with a second on-off valve 11, and one end of the third branch pipe 9a is connected to a third branch pipe 9a in the middle of the discharge pipe 9. The other end of the third branch pipe 9a is connected to the third branch point 9b, and the other end of the third branch pipe 9a is connected to a third confluence point located in the middle of the discharge pipe 9 and closer to the condenser 2 than the third branch point 9b. It is connected to 9c. Furthermore, as shown in FIG.
are arranged for heat exchange.

The operation of the refrigerant amount adjusting device described above will be explained below.

Generally, the temperature of the suction pipe 8 changes sensitively and greatly with respect to load fluctuations, but the temperature at the connection position 3a between the first refrigerant amount adjustment container 5 and the expansion device 3 does not change much.

Now, assume that the refrigerant is filled with the necessary refrigerant so that the refrigeration system exhibits its maximum capacity under certain design heat load conditions. Assuming that the refrigeration system is operated under a certain load condition, the temperature of the suction pipe 8 is also maintained at a certain constant temperature. At this time,
Suction pipe 8 passing through the first refrigerant amount adjustment container 5
The temperature of the first refrigerant amount adjusting container 5 and the expansion device 3
When the load is extremely large, the temperature becomes higher than the temperature at the connection position 3a, and when the load is normal or low, the temperature becomes lower. Further, the temperature of the first branch pipe 7a is higher than the temperature of the connection position 3a. Therefore, the temperature of the refrigerant inside the first refrigerant amount adjustment container 5 becomes higher than the temperature of the refrigerant at the connection position 3a when the load is high, and becomes lower when the load is low.
In addition, under normal load, the first refrigerant amount adjustment container 5
The temperature of the refrigerant inside the first refrigerant amount adjustment container 5 shows a saturation temperature equal to the temperature of the refrigerant at the connection position 3a, but the humidity of the refrigerant inside the first refrigerant amount adjustment container 5 and the humidity of the refrigerant at the connection position 3a are different. become. When adjusting the amount of refrigerant, it is important to adjust the humidity of the refrigerant inside the first refrigerant amount adjustment container 5. In other words, since the difference in specific weight between the gas state and the liquid state of the refrigerant is large, It is important to control the ratio of the liquid phase of the refrigerant inside the first refrigerant amount adjustment container 5.

In FIG. 6, the diameter of the first branch pipe 7a is plotted on the horizontal axis, and the humidity of the refrigerant inside the first refrigerant amount adjustment container 5 is plotted on the vertical axis, under certain design heat load conditions. This figure shows the ratio of the liquid phase of the refrigerant inside the first refrigerant amount adjustment container 5 at . For example, in FIG. 6, if the first branch pipe 7a with a pipe diameter indicated by point h is used, under the design heat load conditions, the wetness of the refrigerant inside the first refrigerant amount adjustment container 5 becomes i. In this way, by appropriately selecting the pipe diameter of the first branch pipe 7a under a certain design heat load condition, the wetness of the refrigerant inside the first refrigerant amount adjustment container 5 can be adjusted appropriately. You can choose.

Next, the operation of the refrigerant amount adjusting device in a normal load range in which the refrigeration system is used will be explained.

In this case, the first on-off valve 10 is closed and the second on-off valve 11 is opened. Assume that the refrigeration system is currently being operated under a certain load (eg, design heat load conditions). The wetness of the refrigerant inside the first refrigerant amount adjustment container 5 (in other words, the first refrigerant amount adjustment container 5
As explained in FIG. 6, the mass of the refrigerant contained inside the first branch pipe 7a can be arbitrarily selected by appropriately selecting the pipe diameter of the first branch pipe 7a. Therefore, the refrigerant inside the first refrigerant amount adjustment container 5 is in a certain gas-liquid two-phase saturated state. In addition, the third branch pipe 9a
Since the high temperature refrigerant passing through and the refrigerant inside the second refrigerant amount adjustment container 6 exchange heat, the refrigerant inside the second refrigerant amount adjustment container 6 becomes superheated steam.

A case in which the load increases from the above load within the normal load range will be explained. When the load increases, the amount of refrigerant circulating in the refrigerant circuit becomes insufficient than the amount of refrigerant that allows the refrigeration system to exhibit its maximum capacity under this load condition. , will be sucked into the compressor 1. In other words, the first refrigerant amount adjustment container 5
The temperature of the suction pipe 8 passing through becomes higher than before the load change.

Therefore, the refrigerant in the saturated liquid state inside the first refrigerant amount adjustment container 5 evaporates, so the wetness of the refrigerant inside the first refrigerant amount adjustment container 5 decreases, and the liquid phase ratio of the refrigerant decreases. becomes smaller. As a result, the mass of the refrigerant contained in the first refrigerant amount adjustment container 5 decreases compared to before the load change. This decreased refrigerant is the refrigerant that was in short supply because the refrigerant inside the first refrigerant amount adjustment container 5 from the connection position 3a in the middle of the expansion device 3 is the refrigerant that has flowed into the refrigerant circuit. Refrigerant will be replenished into the circuit,
The temperature of the suction pipe 8 decreases and becomes balanced with the temperature of the connecting position 3a in the middle of the throttle device 3. Further, since the high temperature refrigerant passing through the third branch pipe 9a and the refrigerant inside the second refrigerant amount adjustment container 6 exchange heat, the refrigerant inside the second refrigerant amount adjustment container 6 is As before the change, since it is superheated steam, the mass of the refrigerant contained inside the second refrigerant amount adjustment container 6 is:
Almost no change.

Next, a case where the load is reduced within the normal load range from a certain load mentioned above (for example, the design thermal load condition) will be described. Under this load condition, an excess amount of refrigerant will be circulating in the refrigerant circuit than the amount of refrigerant that allows the refrigeration system to achieve its maximum capacity.
Refrigerant with almost no superheat is sucked into the compressor 1 through the suction pipe 8. In other words, the temperature of the suction pipe 8 passing through the first refrigerant amount adjustment container 5 becomes lower than before the load decreases. For this reason, the refrigerant in the saturated vapor state inside the first refrigerant amount adjustment container 5 condenses, so the wetness of the refrigerant inside the first refrigerant amount adjustment container 5 increases, and the liquid phase ratio of the refrigerant increases. growing. As a result, the mass of the refrigerant contained inside the first refrigerant amount adjustment container 5 increases compared to before the load change. This increased refrigerant is
In the end, since the refrigerant in the refrigerant circuit is the refrigerant that has flowed into the first refrigerant amount adjustment container 5, the excess refrigerant in the refrigerant circuit is removed, and the temperature of the suction pipe 8 rises to Balances the temperature at the connection position 3a.
Further, since the high temperature refrigerant passing through the third branch pipe 9a and the refrigerant inside the second refrigerant amount adjustment container 6 exchange heat, the refrigerant inside the second refrigerant amount adjustment container 6 is As before the change, since it is superheated steam, the mass of the refrigerant contained inside the second refrigerant amount adjustment container 6 hardly changes.

Next, the operation of the refrigerant amount adjusting device when the load is larger than the normal load range will be explained.

Also in this case, the first on-off valve 10 is closed and the second on-off valve 11 is opened. When the load increases in this way, the temperature of the refrigerant passing through the suction pipe 8 becomes even higher than in the case of a normal load, so the inside of the first refrigerant amount adjustment container 5 is almost saturated steam or superheated steam. It will be occupied by For this reason,
The mass of the refrigerant contained in the first refrigerant amount adjustment container 5 is reduced compared to the case of normal load, and the reduced amount of refrigerant is replenished into the refrigerant circuit. The inside of the second refrigerant amount adjustment container 6 is occupied by superheated steam as in the case of a normal load, and the mass of the refrigerant contained in the second refrigerant amount adjustment container 6 hardly changes.

The operation of the refrigerant amount adjusting device when the load is smaller than the normal load range will be explained.

In this case, the first on-off valve 10 is opened and the second on-off valve 11 is closed. When the load is reduced in this way, the temperature of the refrigerant passing through the suction pipe 8 becomes even lower than in the case of a normal load, so the inside of the first refrigerant amount adjustment container 5 is almost saturated liquid or supercooled liquid. It will be occupied by liquid. Therefore, the mass of the refrigerant contained in the first refrigerant amount adjustment container 5 increases compared to the case of normal load, and the increased amount of refrigerant is removed from the refrigerant circuit. Furthermore, since the low-temperature refrigerant passing through the second branch pipe 8a and the refrigerant inside the second refrigerant amount adjustment container 6 exchange heat, the refrigerant inside the second refrigerant amount adjustment container 6 is It becomes a saturated state of liquid two-phase or a state of supercooled liquid. In this way, the mass of the refrigerant contained in the second refrigerant amount adjustment container 6 is increased compared to the case of normal load, so that excess refrigerant in the refrigerant circuit is removed. In FIG. 7, the horizontal axis represents the size of the load on the refrigeration system, and the vertical axis represents the mass of the refrigerant contained in the second refrigerant amount adjustment container 6. It shows the mass of refrigerant removed from the refrigerant circuit by the regulating container 6.

Next, FIG. 8 shows another embodiment of the refrigerant amount adjusting device according to the present invention. The difference between FIG. 3 and FIG. 8 described above is that in FIG. It is characterized by penetrating the refrigerant amount adjusting container 5, and in FIG.
It is characterized by being penetrated by the

The refrigerant amount adjusting device shown in FIG. 8 also provides the same effects as the previous embodiment. Here, the same parts as in FIG. 3 are given the same numbers, and the explanation will be omitted.

In the examples shown in FIGS. 3, 4, 5, and 8, the connecting pipe 7 connecting the condenser 2 and the throttle device 3, or the first A branch pipe 7a and a suction pipe 8 are passed through the first refrigerant amount adjustment container 5, and a second branch pipe 8a branched from the suction pipe 8 and a third branch pipe branched from the discharge pipe 9. 9a is passed through the second refrigerant amount adjustment container 6, but the meaning of this penetration is that the connecting pipe 7 or the first branch pipe 7a and the suction pipe 8 are connected to the first Furthermore, the second branch pipe 8a and the third branch pipe 9a are caused to exchange heat with the second refrigerant amount regulation container 6, respectively. Therefore, the connecting pipe 7, or the first branch pipe 7a and the suction pipe 8 are brought into contact with the first refrigerant amount adjustment container 5, and the second branch pipe 8a and the third branch pipe 9a are brought into contact with each other.
The refrigerant amount adjusting container 6 may be placed in contact with the second refrigerant amount adjusting container 6 to exchange heat.

As described above, the refrigerant amount adjustment method of the present invention connects a compressor, a condenser, a throttle device, and an evaporator in an annular manner, and condenses the first refrigerant amount adjustment container and the second refrigerant amount adjustment container. A connecting pipe connecting the condenser and the evaporator and connecting the condenser and the throttling device, or a first branch pipe and a suction pipe branched from the connecting pipe to the first refrigerant amount adjusting container. Further, a second branch pipe branched from the suction pipe and a third branch pipe branched from the discharge pipe connecting the compressor and the condenser are respectively connected to the second refrigerant. A first on-off valve is provided in the second branch pipe and a third branch pipe, respectively.
A second on-off valve is provided, and the first on-off valve is closed and the second on-off valve is opened when the load on the refrigeration cycle is within the normal load range or above. Since the first on-off valve is opened and the second on-off valve is closed when the load falls below the normal load range, the refrigerant amount can be adjusted over a wider range of load fluctuations than conventional refrigerant amount adjustment devices. is possible.

Furthermore, unlike conventional refrigerant amount adjustment devices, the first branch pipe, which is a branched connection pipe that connects the condenser and the expansion device, is arranged in the first refrigerant amount adjustment container for heat exchange. By appropriately selecting the pipe diameter of the connecting pipe, the amount of refrigerant that can be stored in the first refrigerant amount adjustment container 5 under the designed heat load conditions can be arbitrarily selected. Therefore, there is an advantage that the size of the first refrigerant amount adjustment container can be easily determined so that the refrigerant amount adjustment function can be sufficiently performed for the maximum load condition and the minimum load condition considered at the time of design.

Furthermore, since the refrigerant amount adjusting device according to the present invention is provided with the second refrigerant amount adjusting container, it can sufficiently perform the refrigerant amount adjusting function, especially in response to load fluctuations at low loads. Therefore, it has the advantage of completely preventing liquid from returning to the compressor.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a refrigeration cycle equipped with a conventional refrigerant amount adjustment device, FIG. 2 is an explanatory diagram showing the heat balance of the refrigerant amount adjustment container, and FIG. 3 is a diagram of a refrigerant amount adjustment device according to an embodiment of the present invention. FIG. 4 is an enlarged partial cross-sectional view showing the first refrigerant amount adjusting container used in the present invention, FIG. 5 is an enlarged partial cross-sectional view showing the second refrigerant amount adjusting container, FIG. 6 is an explanatory diagram showing the humidity of the refrigerant in the first refrigerant amount adjustment container, FIG. 7 is an explanatory diagram showing the mass of the refrigerant in the second refrigerant amount adjustment container, and FIG. FIG. 6 is a refrigeration cycle diagram in another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Compressor, 2... Condenser, 3... Throttling device, 4... Evaporator, 5... First refrigerant amount adjustment container, 6... Second refrigerant amount adjustment container, 7... Connection Pipe, 8...Suction pipe, 9...Discharge pipe, 7a...First branch pipe, 8a...Second branch pipe, 9a...Third branch pipe, 10...First on-off valve, 11...Second on-off valve.

Claims (1)

[Claims] 1. A refrigeration cycle is constructed by connecting a compressor, a condenser, a throttle device, and an evaporator in a ring, and a first refrigerant amount adjustment container and a second refrigerant amount adjustment container are connected in parallel in the middle of the expansion device. Connect the connecting ends of the container,
Further, a connecting pipe connecting the condenser and the throttling device and a suction pipe connecting the compressor and evaporator are respectively disposed for heat exchange with the first refrigerant amount adjustment container, and further branched from the suction pipe. A second branch pipe and a third branch pipe branched from a discharge pipe connecting the compressor and the condenser are respectively disposed in a heat exchange manner with the second refrigerant amount adjustment container, and the second branch pipe ,
The third branch pipe is provided with a first on-off valve and a second on-off valve that open and close depending on the load of the refrigeration cycle, respectively, and when the load of the refrigeration cycle is within the normal load range or higher, the first on-off valve and the second on-off valve are provided. The on-off valve is closed and the second on-off valve is opened, and when the load of the refrigeration cycle falls below the normal load range, the first on-off valve is opened and the second on-off valve is closed. A method for adjusting the amount of refrigerant in a refrigeration system.