JPH0373793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat pump system having air conditioning and hot water supply functions.

(Prior Art) In a heat pump system having refrigeration cycles with different loads in one device, as a specific method for improving the efficiency of each refrigeration cycle, for example, Japanese Patent Application Laid-Open No. 162159/1982 discloses cold·
In an air conditioner for both heating and heating, a device is shown that varies the amount of refrigerant during cooling and heating. Third
The figure shows a refrigerant circuit diagram of the above device. In the figure, a compressor 41 is connected to a four-way switching valve 42 for switching between cooling and heating, and an indoor heat exchanger 43 and an expansion valve are connected to the four-way switching valve 42. 44 and an outdoor heat exchanger 45 are sequentially connected by piping. Then, in the piping connecting the four-way switching valve 42 and the indoor heat exchanger 43,
A container 47 containing refrigerator oil 46 is interposed. The above device attempts to change the amount of circulating refrigerant by using a mixed refrigerant whose solubility in refrigeration oil varies depending on pressure and temperature.During indoor heating operation in which the refrigerant is circulated in the direction of the solid arrow in the figure, The high-temperature, high-pressure gas refrigerant discharged from the compressor 41 first flows into the container 47, and then circulates through the indoor heat exchanger 43, the expansion valve 44, and the outdoor heat exchanger 45. On the other hand, during indoor cooling operation in which the refrigerant is circulated in the direction of the dashed arrow in the figure, the refrigerant flows into the container 47.
The low-temperature, low-pressure gas refrigerant flows through the indoor heat exchanger 45. At this time, for example, SUNISO 4GS (trade name) is used as refrigerating machine oil.
When using a non-azeotropic mixed refrigerant of R13B1 and R12 as a refrigerant, the solubility in Suniso 4GS is that at high temperature and high pressure, R13B1 is small and R12 is large, so R12 dissolves in a large amount in Suniso 4GS, Therefore, the circulating refrigerant has a composition with a high concentration of R13B1, which is a low boiling point refrigerant. On the other hand, at low temperature and low pressure, the difference in solubility between R13B1 and R12 disappears compared to at high temperature and high pressure, and the circulating refrigerant is a high boiling point refrigerant.
This results in a mixed refrigerant with strong R12 characteristics. In general, the lower the boiling point refrigerant, the smaller the compressor's suction specific volume, the larger the refrigerant circulation amount, and the higher the capacity.
The refrigerant composition has a high refrigerant composition, increasing the heating capacity, while during cooling operation, the cooling capacity is reduced by the action of the high boiling point refrigerant R12, thereby improving efficiency during each cooling/heating operation.

(Problems to be Solved by the Invention) Recently, heat pump systems have appeared that have not only the above-mentioned air conditioning function but also a hot water supply function that heats hot water by installing a heat exchanger in a hot water storage tank. In this case, when switching to the hot water supply cycle with the amount and type of refrigerant that are compatible with the air conditioning refrigeration cycle, there was a problem that the discharge pressure of the compressor would abnormally increase. This is because as the water temperature in the hot water storage tank rises, the amount of heat exchanged in the hot water heat exchanger, which acts as a condenser, decreases, resulting in an increase in the condensing temperature and therefore the condensing pressure. . Therefore, by switching to a refrigerant with a higher boiling point that is more likely to liquefy than the refrigerant used during the air conditioning cycle, it is possible to prevent the above-mentioned abnormalities from occurring. However, the occurrence of the abnormal pressure increase described above occurs within a short time after switching to the hot water supply cycle if the water temperature in the hot water storage tank has risen to a certain extent, so in order to prevent this, the above It is necessary to quickly change the type of refrigerant. In the conventional apparatus described above, the refrigerant composition is varied by utilizing the solubility of the refrigerant in the refrigerating machine oil, but it takes a long time to reach the desired refrigerant composition. This is because the gas refrigerant flowing into the container 47 containing the refrigerant oil 46 is dissolved or released through the liquid level of the refrigerant oil 46, and therefore the time required to reach an equilibrium state is the gas phase. This is because it depends on the diffusion rate due to the difference in concentration in the liquid. Furthermore, in order to obtain a predetermined amount of dissolution, it is necessary that the refrigerating machine oil 46 is at a temperature that can provide the solubility.
6 itself has a heat capacity. Therefore, when switching from heating to cooling, for example, the container 47 and the refrigerating machine oil 46, which are at a high temperature, are heated to a predetermined level by the low temperature gas refrigerant flowing into them. This is because it takes a long time to reach the low temperature state.

The present invention has been made in view of the above-mentioned points, and its purpose is to prevent an abnormal increase in the discharge gas pressure of the compressor when switching from the air conditioning cycle to the hot water supply cycle in a heat pump system having air conditioning and hot water supply functions. It is an object of the present invention to provide a heat pump system that can quickly change the refrigerant composition so as to prevent the occurrence of.

(Means for solving the problem) Therefore, the heat pump system of this invention is
One of the outdoor and indoor heat exchangers 10, 20, 21, 22 connected to each other by a liquid pipe 11 is connected to the discharge pipe 2 of the compressor 1 via the first gas pipe 3, and the other one is connected to the discharge pipe 2 of the compressor 1 via the first gas pipe 3. A heat exchanger is connected to the suction pipe 6 of the compressor 1, and a hot water supply heat exchanger 28 connected to the liquid pipe 11 is connected between the first gas pipe 3 and the discharge pipe 2. 25, the discharge pipe 2 of the compressor 1 is connected to the first
Air conditioning operation connected to the gas pipe 3 and the compressor 1
It is possible to switch between the hot water supply operation in which the discharge piping 2 is connected to the hot water supply heat exchanger 28, and the refrigerant flowing in these piping is controlled to have different solubility in the refrigerating machine oil in two states: high temperature high pressure side and low temperature low pressure side. The heat pump system is composed of a non-azeotropic mixed refrigerant in which the difference between the high boiling point refrigerant and the low boiling point refrigerant is larger, and the first gas pipe 3 is connected to the discharge gas from the compressor 1. A liquid reservoir 26 for storing refrigerating machine oil mixed in the discharged gas refrigerant during air conditioning operation in which refrigerant is supplied to the first gas pipe 3 is interposed, and a liquid reservoir 26 is provided between the liquid reservoir 26 and the suction pipe 6. is suction pipe 35
The switching means 25 is connected to the suction pipe 35 in order to discharge the liquid in the liquid reservoir 26 to the suction pipe 6 by the suction pressure of the compressor 1 during hot water supply operation.
It is characterized by interposing a shutoff valve 25 that opens in conjunction with the air conditioner and closes during air conditioning operation.

(Function) In the heat pump system configured as described above, when the switching means 25 is operated in a non-hot water supply operation, that is, in the switching position of the air conditioning cycle, the liquid reservoir 26 is configured such that the gas refrigerant discharged from the compressor 1 flows through the switching means 25. The refrigerating machine oil, which is located at a location where the refrigerant is mixed with the refrigerant and circulates within the piping, gradually accumulates in the liquid reservoir 26. The refrigerating machine oil and liquid reservoir 26 that have accumulated during this period are in a high temperature and high pressure state due to the action of the discharged gas refrigerant. On the other hand, from this state, when the switching means 25 is switched to hot water supply operation and the cutoff valve 25 is opened, the liquid reservoir 26 is connected to the suction pipe 6 side of the compressor 1 via the suction pipe 35. Under the action of the suction pressure of the compressor 1, the refrigerating machine oil in the liquid reservoir 26 rapidly flows into the suction pipe 6.
It is sucked out to the side. Since a low-temperature, low-pressure gas refrigerant always flows through the suction pipe 6, the refrigerating machine oil discharged from the liquid reservoir 26 to the suction pipe 6 side rapidly changes to a low-temperature, low-pressure state. At this time, the refrigerant flowing in the pipe is composed of a non-azeotropic mixed refrigerant in which the difference in solubility in the refrigerating machine oil in the two states of high temperature and high pressure and low temperature and low pressure is larger in the high boiling point refrigerant than in the low boiling point refrigerant. Therefore, during the air conditioning cycle, a large amount of high-boiling point refrigerant dissolves in the high-temperature, high-pressure refrigerating machine oil in the liquid reservoir 26, so a refrigerant with a composition containing less high-boiling point refrigerant circulates through the pipes.On the other hand, after the hot water supply cycle is switched, Since the refrigerating machine oil rapidly changes to a low temperature and low pressure state, the high boiling point refrigerant dissolved therein will be released within a short period of time.
As a result, when the hot water supply operation is switched, the refrigerant circulating through the pipes quickly becomes a composition with a high boiling point refrigerant, so the condensation pressure does not increase as described above, and the discharge gas of the compressor 1 This makes it possible to prevent abnormal pressure increases from occurring.

(Example) Next, a specific example of the heat pump system of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a refrigerant circuit diagram showing the overall configuration in an embodiment of the present invention, including one outdoor heat exchanger 10, three indoor heat exchangers 20, 21, 22, and one hot water supply heat exchanger. It is configured as a three-chamber air conditioning and hot water heat pump system with an exchanger 28. In the figure, the outdoor heat exchanger 10 is a liquid pipe 11
are connected to indoor heat exchangers 20, 21, and 22 arranged in each room, respectively. In this liquid pipe 11, a main pipe expansion valve 12, a receiver tank 13, and a liquid closing valve 14 are sequentially installed from the outdoor heat exchanger 10 side, and this liquid closing valve 14 and each of the indoor heat exchangers 20 , 21, 22 are branched into three branch liquid pipes 202, 212, 222 with branch pipe expansion valves 201, 211, 221 interposed therein, respectively. And each of the above indoor heat exchangers 2
0, 21, and 22 have branch gas pipes 203 and 22, respectively.
213, 223 are connected, and the confluence of these branch gas pipes 203, 213, 223 is connected by an indoor gas pipe 16 in which a gas shutoff valve 15 is interposed, and the outdoor heat exchanger 10 is Each of them is connected by an outdoor gas pipe 17 to a four-way switching valve (hereinafter referred to as a heating/cooling switching valve) 18 for switching between cooling and heating. On the other hand, the discharge pipe 2 of the compressor 1 is connected to the four-way switching valve 2.
5, one connection port of the four-way switching valve 25 that can communicate with the discharge pipe 2;
One connection port of the heating/cooling switching valve 18 is connected to the first gas pipe 3 in which a liquid reservoir 26 is interposed, and the other connecting port of the heating/cooling switching valve 18 is connected to two AC pipes. It is connected to the suction pipe 6 in which the multors 4 and 5 are interposed, thereby forming an air conditioning refrigerant circulation circuit.

The four-way switching valve 25 serves as a switching means for switching between air conditioning and hot water supply, and serves as a switching means for switching between air conditioning and hot water supply.
The other connection port that can communicate with the hot water tank 27
A heat exchanger 28 for hot water supply installed inside is connected to a hot water supply gas pipe 30 in which a gas shutoff valve 29 is interposed. In addition, this hot water supply heat exchanger 28
is connected to a receiver tank 13 provided in the liquid pipe 11 through a hot water supply liquid pipe 32 provided with a liquid shutoff valve 31 . Further, a liquid pipe 1 is connected to the hot water supply liquid pipe 32 from the hot water supply heat exchanger 28 side.
Check valve 3 in a direction that allows refrigerant flow toward the 1 side
3, and a solenoid valve 34 which is connected in parallel to the check valve 33 and is closed except during defrost operation. In the four-way switching valve 25, a connection port that can communicate with the hot water supply gas pipe 30 and the first gas pipe 3 is located between the cooling/heating switching valve 18 of the suction pipe 6 and the accumulator 5. , are connected by a suction pipe 35. Therefore, in the four-way switching valve 25, at a position where the suction pipe 35 communicates with the first gas pipe 3, a refrigerant flow occurs from the first gas pipe 3 side to the suction pipe 35 side, and on the other hand, the hot water supply At the position communicating with the gas pipe 30, no refrigerant flow occurs through these pipes, as will be described later.
It also has a function as a shutoff valve provided in the suction pipe 35.

The operating state of the above-described embodiment configured as described above will be explained next. First, during air conditioning operation to cool or heat the room, the four-way selector valve 25 is switched so that the refrigerant flows as shown by solid lines and broken line arrows in the figure. That is, the high temperature and high pressure gas refrigerant discharged from the compressor 1 is transferred to the discharge pipe 2 and the four-way switching valve 2.
5, flows into the first gas pipe 3, and is supplied to the cooling/heating switching valve 18 through a liquid reservoir 26 provided therein. Then, depending on the switching position of the heating/cooling switching valve 18, the indoor heat exchanger 20,
The heating cycle circulates from the 21, 22 side to the outdoor heat exchanger 10 side, and the heating cycle circulates from the outdoor heat exchanger 10 side to the indoor heat exchanger 20, 21, 22 in the direction of the broken line arrow.
The cooling cycle circulation to the side is performed, and the low-temperature, low-pressure gas refrigerant that returns to the cooling/heating switching valve 18 is returned to the compressor 1 through the suction pipe 6. At this time, the hot water supply gas pipe 30 connected to the hot water supply heat exchanger 28 is connected to the suction pipe 6 on which low pressure is applied via the four-way switching valve 25 and the suction pipe 35.
Therefore, a pressure difference in the flow blocking direction is applied to the check valve 33 interposed in the hot water supply liquid pipe 32, so no refrigerant flow occurs in the hot water supply heat exchanger 28. , hot water heating is stopped. Also,
At this time, the refrigerating machine oil mixed with the circulating refrigerant and circulating in the pipes is separated from the gas refrigerant in the accumulators 4 and 5, and accumulates in the accumulators 4 and 5, and as shown in FIG. As schematically shown inside the medium storage unit 5,
The internal communication pipe 7 on the compressor 1 side is composed of a hook-shaped pipe that extends to the bottom and goes further upward, and a small hole 8 is provided at the bottom position.
Therefore, an appropriate amount of the refrigerating machine oil accumulated in the accumulators 4 and 5 is sucked out through the small hole 8 and flows into the compressor 1 together with the gas refrigerant. On the other hand, a gas refrigerant mixed with oil is discharged from the compressor 1 through a discharge pipe 2, and the amount of refrigerating machine oil contained in this discharged gas refrigerant and the amount of refrigerating machine oil flowing in from the accumulators 4 and 5 are The amount of refrigerating machine oil in the compressor 1 is maintained in a balanced state. The gas refrigerant discharged to the discharge pipe 2 is supplied to the cooling/heating switching valve 18 via the liquid reservoir 26 interposed in the first gas pipe 3. As the internal structure of this liquid reservoir 26 is schematically shown in FIG. 1, for example,
The internal communication pipe 36 on the four-way switching valve 25 side is a straight pipe that opens close to the bottom, and the internal communication pipe 37 on the other cooling/heating switching valve 18 side is a short pipe. It has a liquid separation function, so when the gas refrigerant mixed with refrigerating machine oil flows through this liquid reservoir 26, the refrigerating machine oil is separated and gradually accumulates in this liquid reservoir 26. I have to go. Due to the above, during the above air conditioning operation,
The refrigerating machine oil accumulated in the accumulators 4 and 5 is gradually transferred to the liquid reservoir 26. The refrigerating machine oil to be transferred is at a low temperature and low pressure before being transferred, but after being transferred, it is exposed to the discharge gas refrigerant of the compressor 1, so it is in a high temperature and high pressure state.

Next, the operating state of hot water supply operation will be explained.
In FIG. 1, hot water is heated by circulating the refrigerant in the direction indicated by the dashed-dotted arrow.
That is, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is transferred to the discharge pipe 2, the four-way switching valve 25, the gas pipe 30 for hot water supply, the heat exchanger 28 for hot water supply, and the liquid pipe 3 for hot water supply.
2, it flows into the receiver tank 13 interposed in the liquid pipe 11. And the cooling/heating switching valve 18
By switching the outdoor heat exchanger 10 to a position where it communicates with the suction pipe 6, the refrigerant flowing from the hot water supply heat exchanger 28 into the receiver tank 13 is
The water is returned to the compressor 1 via the outdoor heat exchanger 10, the outdoor gas pipe 17, the cooling/heating switching valve 18, and the suction pipe 6. At this time, the hot water supply heat exchanger 28 acts as a condenser, and the hot water is Heating takes place. Note that at this time, the indoor heat exchangers 20, 21, and 22 are communicated with the suction pipe 6 via the indoor gas pipe 16, the cooling/heating switching valve 18, the first gas pipe 3, the four-way switching valve 25, and the discharge pipe 35. Therefore, the branch pipe expansion valves 201, 2
11 and 221, it is also possible to perform simultaneous indoor cooling operation.

As mentioned above, by switching the four-way switching valve 25, the air conditioning operation is switched to the hot water supply operation, but at the same time as the switching of the four-way switching valve 25, the The liquid reservoir 26 is switched from communicating with the discharge pipe 2 to communicating with the suction pipe 6 via the suction pipe 35, and the suction pressure of the compressor 1 is applied thereto. Therefore, as described above, the refrigerating machine oil that exceeds the opening position of the internal communication pipe 36 extending to the bottom of the liquid reservoir 35 is rapidly sucked out to the suction pipe 6 side. The sucked-out refrigerating machine oil is brought into a low-temperature, low-pressure state almost at the same time as it is transferred to the suction pipe 6 side where the accumulators 4 and 5 are interposed.

As explained above, in the above embodiment,
Surplus refrigerating machine oil other than the appropriate amount of refrigerating machine oil required for the operation of the compressor 1 is gradually stored in the liquid reservoir 26 at high temperature and pressure during non-hot water supply operation (air conditioning operation), while during hot water supply operation. At approximately the same time as the switching, the high-temperature, high-pressure refrigerating machine oil is sucked out to the suction pipe 6 side, resulting in a low-temperature, low-pressure state. In the above embodiment, the refrigerant has different boiling points.
For example, a mixed refrigerant of R22 and R114 is used, and Suniso 4GS is used as the refrigerating machine oil. Figure 2 a, b
shows the solubility characteristics of R22 and R114 in Suniso 4GS, respectively.
As shown in Figure a, there is almost no difference in the solubility of R22 under the operating conditions of the above device, that is, the pressure is below 20 kg/cm ² and the oil temperature is below 120°C.
In R114, as shown by A and B in the same figure b,
The solubility differs greatly between the two states of high temperature and high pressure obtained in the above device and low temperature and low pressure. In other words, there is a large amount of high temperature and high pressure refrigeration oil.
R114 is absorbed, and when this refrigerating machine oil becomes low temperature and pressure, the absorbed R114 is released. Therefore, as mentioned above, during non-hot water supply operation, a large amount of R114 is absorbed into the refrigerating machine oil stored in the liquid equalizer 26, so in the air conditioning refrigerant circulation cycle, a high boiling point refrigerant with a composition that is low in R114 is used. The refrigerant is circulated to maintain the same air conditioning capacity as before. On the other hand, during hot water supply operation, the above-mentioned
R114 is released from the refrigeration oil and therefore
A refrigerant having a composition with a high boiling point refrigerant R114 will be circulated. This makes it possible to prevent an abnormal increase in the discharge gas pressure from the compressor 1, which occurs in conventional devices.

As explained above, in the above embodiment,
When switching hot water supply operation, the composition quickly changes to a high-boiling refrigerant-rich composition, which prevents abnormal pressure increases.
Furthermore, since the degree of pressure rise is reduced, it is also possible to raise the temperature of boiling water compared to the conventional method. Furthermore, in the past, a refrigerant that could be used for both air conditioning and hot water supply operations was selected, and as a result, the equipment configuration was configured in such a way that each capacity had to be suppressed, but according to the above embodiment, Since the refrigerant composition is automatically changed to suit each air conditioning cycle and hot water supply cycle, each capacity can be improved. In addition, in the description of the above embodiment, the internal flow pipe 36 of the liquid reservoir 26 is configured as a straight pipe that opens at the bottom, but at this time, the gas refrigerant that flows in during the air conditioning cycle bubbles through the refrigerating machine oil. This has the effect of dissolving the gas refrigerant into the refrigerating machine oil more quickly.

In addition, in the above embodiment, as an example,
Although R22, R112, and Suniso 4GS are mentioned, as explained above, other refrigerants and refrigerating machine oil can be used as long as the combination causes a large difference in solubility depending on the refrigerant on the high boiling point side. In addition, a four-way switching valve 2 that serves both functions as a switching means and a shutoff valve.
5, but for example, if the discharge pipe 2 can be switched between the first gas pipe 3 and the hot water supply gas pipe 30, it can be constructed with a three-way valve or other valves, and in this case, The suction pipe 35 may be provided with its own cutoff valve and may also be configured to be directly connected to the liquid reservoir 26. Furthermore, the accumulators 4 and 5 interposed in the suction pipe 6 can be modified by adding, for example, a region with a large pipe diameter to the suction pipe 6 so as to have a liquid storage function. It can also be omitted.

(Effects of the Invention) As described above, in the heat pump system of the present invention, refrigerating machine oil is stored in the reservoir at high temperature and pressure during air conditioning operation, while refrigerating machine oil in the reservoir is stored in the compressor during hot water supply operation. Since the high boiling point refrigerant is quickly discharged and the refrigerant composition quickly changes to include a large amount of this high boiling point refrigerant, the hot water in the hot water storage tank is Even if the temperature rises, the condensing pressure does not rise, and therefore, it is possible to prevent the pressure of the gas discharged from the compressor from increasing abnormally.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram showing the overall configuration of an embodiment of the heat pump system of the present invention, and FIG.
Figures a and b are graphs showing the solubility of R22 and R114 in Suniso 4GS, and Figure 3 is a refrigerant circuit diagram of a conventional air conditioner. 1...Compressor, 2...Discharge pipe, 3...First gas pipe, 6...Suction pipe, 10...Outdoor heat exchanger,
11... Liquid pipe, 20, 21, 22... Indoor heat exchanger, 25... Four-way switching valve (switching means) (shutoff valve),
26...Liquid reservoir, 28...Hot water supply heat exchanger, 35
...Suction tube.

Claims (1)

[Claims] 1 One of the outdoor and indoor heat exchangers 10, 20, 21, 22 connected to each other by the liquid pipe 11 is connected to the discharge pipe 2 of the compressor 1 via the first gas pipe 3, and the other The heat exchanger of the above compressor 1
The hot water supply heat exchanger 28 connected to the suction pipe 6 and the liquid pipe 11 is connected to the first gas pipe 3.
By connecting to the switching means 25 connected between the discharge pipe 2 and the discharge pipe 2 of the compressor 1,
It is possible to switch between an air conditioning operation in which the compressor 1 is connected to the first gas pipe 3 and a hot water supply operation in which the discharge pipe 2 of the compressor 1 is connected to the hot water supply heat exchanger 28, and the refrigerant flowing in these pipes is , a heat pump system comprising a non-azeotropic mixed refrigerant in which the difference in solubility in two states of refrigerating machine oil, high-temperature, high-pressure side and low-temperature, low-pressure side, is larger for the high-boiling point refrigerant than for the low-boiling point side refrigerant; , the compressor 1 is connected to the first gas pipe 3.
A liquid reservoir 26 is provided to store refrigerating machine oil mixed in the discharged gas refrigerant during air conditioning operation in which the discharged gas refrigerant is supplied to the first gas pipe 3, and the liquid reservoir 26 and the suction pipe 6 is connected by a suction pipe 35, and this suction pipe 35 is equipped with the above-mentioned switching switch in order to discharge the liquid in the liquid reservoir 26 to the suction pipe 6 by the suction pressure of the compressor 1 during hot water supply operation. A heat pump system characterized by interposing a shutoff valve 25 which opens in conjunction with means 25 and closes during air conditioning operation.