JPH0718620B2 - Heat pump system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat pump system including a heat storage device for defrost operation that stores heat generated by a compressor.

(Prior Art) In this type of heat pump system, the sixth
The system shown in the figure is known (for example, Japanese Patent Laid-Open No. 63-
169457 publication). In this system, a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, an expansion valve (pressure reducing mechanism) 4, and an indoor heat exchanger 5 are sequentially connected by a refrigerant pipe 6, and a defrosting operation (defrost) is performed. It has a heat storage device 7 for. In this heat storage device 7, the compressor 1 is surrounded by a heat storage heat exchanger 8,
The outflow pipe 9 of the heat storage heat exchanger 8 is connected to the refrigerant pipe 6 between the outdoor heat exchanger 1 and the expansion valve 4, and the heat storage heat exchanger 8 is connected.
Is connected to the refrigerant pipe 6 on the indoor heat exchanger 5 side of the expansion valve 4, the check valve 11 is provided in the outflow pipe 9, and the first opening / closing valve 12 is provided in the inflow pipe 10. It is configured by interposing.

In this conventional system, in the heating state in which the four-way switching valve 2 is switched to the illustrated state, the refrigerant circulates through the heating cycle along the broken line arrow in the figure, while in the cooling state in which the four-way switching valve 2 is switched in the opposite direction, The refrigerant circulates in the cooling cycle along the solid arrow.

By the way, in the above-mentioned conventional system, for example, when a leak occurs in the check valve 11 during the cooling operation, the lubricating oil of the compressor 1 mixed in the refrigerant enters the heat storage heat exchanger 8,
Lubricating oil stays in the heat storage heat exchanger 8, causing a shortage of lubricating oil in the compressor 1. The same problem also occurs when the first on-off valve 12 leaks during heating.

Therefore, the present applicant has proposed the system of Japanese Patent Application No. 1-211932 in order to solve the above problems. This system will be described with reference to FIG. 1 which is an embodiment of the present application. This system connects a bypass pipe 31 between the outflow pipe 9 and the return pipe 30 of the compressor 1, and a check valve is connected to the bypass pipe 31. The valve and the second opening / closing valve 33 are interposed. In this system, the second open / close valve 33 is maintained in the open state during the cooling operation, the first open / close valve 12 is opened to the short defect, and the second open / close valve 33 is opened during the normal heating operation.
Is maintained, and control is performed such that the first opening / closing valve 12 is temporarily opened immediately after the compressor 1 is started, whereby refrigerant and lubrication accumulated in the heat storage heat exchanger 8 The oil is returned to the return pipe 30 of the compressor 1.

(Problems to be Solved by the Invention) In the conventional system described above, the recovery operation involving opening and closing of the first opening / closing valve 12 is performed regardless of the amount of lubricating oil or refrigerant stored in the heat storage heat exchanger 8. , Will be compulsorily performed in accordance with the activation of the compressor 1. As a result, a wasteful recovery operation is performed, noise is generated, and the first opening / closing valve
In addition to the problem that the service life of 12 decreases, at the start of the cooling operation or the heating operation, there is a disadvantage that the cooling capacity and the quick heating property are reduced due to useless operation.

The present invention has been made to solve the above-mentioned conventional drawbacks, and its purpose is to perform a recovery operation of lubricating oil and a refrigerant.
It is to provide a heat pump system that can be performed in good timing.

(Means for Solving the Problem) Therefore, in the heat pump system according to the first aspect, the indoor heat exchanger 5, the outdoor heat exchanger 3, the four-way switching valve 2, the pressure reducing mechanism 4, and the compressor 1 are connected by the refrigerant pipe 6. In addition, a heat storage heat exchanger 8 for defrost operation that stores the heat generated from the compressor 1 is arranged around the compressor 1, and a refrigerant pipe 6 between the outdoor heat exchanger 3 and the pressure reducing mechanism 4 is provided. An outflow pipe 9 that connects the heat storage heat exchanger 8 is provided, and the refrigerant pipe 6 and the heat storage heat exchanger 8 between the indoor heat exchanger 5 and the pressure reducing mechanism 4 are provided.
An inflow pipe 10 for connecting with and is provided, and an on-off valve 12 is provided in the inflow pipe 10, while a check valve in which the refrigerant flows in the outflow pipe 9 from the heat storage heat exchanger 8 to the refrigerant pipe 6 in only one direction. Valve 11
And the return pipe 30 on the heat storage heat exchanger 8 side from the check valve 11 and the return pipe 30 of the compressor 1 are connected by a bypass pipe 31 provided with flow resistances 20 and 30. A heat pump system comprising a first temperature sensor 34 for detecting the temperature of the heat storage heat exchanger 8, a second temperature sensor 35 for detecting the temperature of the outdoor heat exchanger 3, and the indoor heat exchange. Third temperature sensor 36 for detecting temperature of vessel 5
And opening / closing to temporarily open the open / close valve 12 after the compressor 1 is started when the temperature detected by the first temperature sensor 34 among the first to third temperature sensors 34, 35, 36 is the lowest. A valve control means 37 is provided.

Further, in the heat pump system according to the second aspect, the flow resistance is constituted by the capillary tube 20 or the electromagnetic opening / closing valve 33.

(Operation) While the compressor 1 is stopped, the refrigerant tends to be stored in the lowest temperature part of the circuit, but the lubricating oil is also stored in the lowest temperature part. Will be. On the other hand, the shortage of refrigerant or lubricating oil in the circuit becomes a problem when a large amount of refrigerant or lubricating oil stays in the heat storage heat exchanger 8 and cannot be circulated in the circuit. Therefore, in such a case, it is particularly necessary to perform the operation of recovering the refrigerant or the lubricating oil.

Therefore, in the heat pump system according to the first aspect, when the temperature of the heat storage heat exchanger 8 is lower than the temperatures of the other heat exchangers 3 and 5, that is, the refrigerant and the lubricating oil stay in the heat storage heat exchanger 8. When it is highly possible that the opening / closing valve 12 is opened, the pressure of the refrigerant acting on the inflow pipe 10 causes the lubricating oil and the refrigerant retained in the heat storage heat exchanger 8 to
It is recovered from the outflow pipe 9 to the compressor 1 through the low pressure loss bypass pipe 31.

The flow resistance in the first claim is, as described in the second claim, the capillary tube 20 and the solenoid on-off valve 3.
3 or other structures can be used.

(Embodiment) Next, a specific embodiment of the heat pump system of the present invention will be described in detail with reference to FIGS. 1 to 3.

In this system, a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, an expansion valve (pressure reducing mechanism) 4, and an indoor heat exchanger 5 are sequentially connected by a refrigerant pipe 6, and a defrosting operation (defrost) is performed.
It has a heat storage device 7 for. The heat storage device 7 encloses the compressor 1 with a heat storage heat exchanger 8 and connects an outflow pipe 9 of the heat storage heat exchanger 8 to a refrigerant pipe 6 between the outdoor heat exchanger 1 and the expansion valve 4. On the other hand, the inflow pipe of the heat storage heat exchanger 8
10 is connected to the refrigerant pipe 6 on the indoor heat exchanger 5 side of the expansion valve 4, the check valve 11 is provided in the outflow pipe 9, and the first opening / closing valve 12 is provided in the inflow pipe 10. Is configured.

In FIG. 1, a bypass pipe 31 is connected between the check valve 11 of the outflow pipe 9 on the heat storage heat exchanger 8 side and the return pipe 30 to the compressor 1. A second opening / closing valve 33 is provided in the middle of the bypass pipe 31, so that the refrigerant and the lubricating oil staying in the heat storage heat exchanger 8 are returned to the return pipe 30 through the bypass pipe 31. Has been done.
Although not shown, at the position of the bypass pipe 31 on the return pipe 30 side, there is provided a check valve arranged so as to prevent the refrigerant from flowing from the return pipe 30 side to the outflow pipe 9 and transmit the pressure. It may be installed.

Furthermore, the compressor 1 has a temperature Tcomp at the bottom of the compressor 1,
That is, the first temperature sensor 34 for detecting the temperature of the heat storage heat exchanger 8 is attached, and the outdoor heat exchanger 3 and the indoor heat exchanger 5 have the same temperature. TC, TE
The second and third temperature sensors 35 and 36 for detecting the temperature are attached, respectively. The outputs of the temperature sensors 34, 35, 36 are respectively the first on-off valve control section (on-off valve control means) 37.
However, the control section 37 performs the following control.

The flowchart is shown in FIG. 2. First, when the compressor 1 is started by operating an operation switch (not shown), the second opening / closing valve 33 is opened (step S1),
The temperature Tcomp of the first temperature sensor 34 is set to the other temperature sensor 3
The temperatures TC and TE of 5 and 36 are compared (step S2). When the temperature Tcomp of the first temperature sensor 34 is the lowest,
While the first opening / closing valve 12 is opened for a fixed time T (step S3), otherwise, the closed state of the first opening / closing valve 12 is maintained (step S4).

Next, the operating state of the heat pump system, that is, the operation control method will be described. First, in the cooling operation in which the four-way switching valve 2 is switched in the opposite direction to that shown in FIG. 1 and the first opening / closing valve 12 is closed, the gaseous refrigerant compressed by the compressor 1 is connected to the refrigerant pipe along the solid line arrow. 6 flows clockwise in the figure, and the outdoor heat exchanger 3
After being condensed by the expansion valve 4 and decompressed by the expansion valve 4, it is evaporated in the indoor heat exchanger 5. Refrigerant gas from the indoor heat exchanger 5 is returned to the compressor 1 via the four-way switching valve 2.

In the above cooling cycle, the high-pressure refrigerant flows on the upstream side of the expansion valve 4, and the pressure also acts on the outflow pipe 9 of the heat storage device 7. At this time, if a leak occurs in the check valve 11 of the outflow pipe 9, the refrigerant flows backward in the outflow pipe 9 and flows into the heat storage heat exchanger 8. By the way, the refrigerant contains the lubricating oil of the compressor 1, and the lubricating oil that has flown into the heat storage heat exchanger 8 together with the refrigerant will stay in the heat storage heat exchanger 8.

Therefore, the lubricating oil accumulated in the heat storage heat exchanger 8 is returned to the return pipe 30 of the compressor 1 through the bypass pipe 31 and recovered to the compressor 1 as follows, and the lubricating oil is stored in the heat storage heat exchanger 8. Are prevented from staying. That is, during the cooling operation, as shown in the time chart of FIG. 3, the second opening / closing valve 33 of the bypass pipe 31 is always opened (ON) during the operation of the compressor 1.
In this state (while the compressor 1 is stopped, the second on-off valve 33 is closed), in this state, when the temperature of the heat storage heat exchanger 8 is the lowest, 1 on-off valve 12,
Immediately after starting the compressor 1, the valve is opened for a predetermined time T, and
The refrigerant is introduced into the heat storage heat exchanger 8 through the inflow pipe 10 only when the on-off valve 12 is opened. Then, the lubricating oil staying in the heat storage heat exchanger 8 is pushed out by the pressure of this refrigerant and is recovered from the outflow pipe 9 through the bypass pipe 31 and the return pipe 30 to the compressor 1. Become.

In addition, when the four-way switching valve 2 having a configuration in which the four-way switching valve 2 naturally returns to the heating operation position when the operation of the air conditioner is stopped in the cooling operation state, the The high-pressure refrigerant from the heat exchanger 3 may act as a back pressure on the second opening / closing valve 33 via the bypass pipe 31, which may cause abnormal noise or infiltration of lubricating oil into the heat storage heat exchanger 8. When a non-return valve is provided in the bypass pipe 31, it is possible to prevent the generation of abnormal noise and the infiltration of lubricating oil into the heat storage heat exchanger 8 as described above. However, in this example,
After the cooling operation is stopped and the four-way switching valve 2 is restored, the check valve is omitted by performing control such that the second opening / closing valve 33 is closed at a stage after the bypass pipe 31 is pressure-equalized. is doing.

On the other hand, in the heating operation in which the four-way switching valve 2 is switched to the state shown in FIG. 1, the high-pressure gas refrigerant from the compressor 1 flows through the refrigerant pipe 6 along the broken line arrow, and the refrigerant condensed in the indoor heat exchanger 5 is After passing through the expansion valve 4 to be decompressed, it is evaporated in the outdoor heat exchanger 3, passes through the four-way switching valve 2 again, and passes through the compressor 1
Reflux to. When there is a leak in the first on-off valve 12, a part of the refrigerant passes through the inflow pipe 10 and stays in the heat storage heat exchanger 8, so that the lubricating oil of the compressor 1 contained in the refrigerant remains. Stays the same as when cooling.

When the above heating cycle is continued, the heat generated from the compressor 1 is accumulated in the heat storage heat exchanger 8 and the heat storage device 7 stores the amount of heat for defrost operation. This defrost operation is performed when frost forms on the outdoor heat exchanger 3, and while the compressor 1 continues to operate, the expansion valve 4 is closed and the first on-off valve 12 of the inflow pipe 10 is opened. The second opening / closing valve 33 is closed while the valve is opened (see FIG. 3). In this state, the refrigerant discharged from the indoor heat exchanger 5 flows into the heat storage heat exchanger 8 through the inflow pipe 10, absorbs the stored heat for the defrost operation, and is heated, and then the outflow pipe 9 After passing through the check valve 11 to the refrigerant pipe 6 near the outdoor heat exchanger 3, the refrigerant flows into the outdoor heat exchanger 3 to remove the frost. During this defrost operation, the lubricating oil staying in the heat storage heat exchanger 8 is recovered.

Then, if the air conditioner is stopped for a long period of time, such as in the off-season, the refrigerant and the lubricating oil will stay in the heat storage heat exchanger 8. However, due to this, the refrigerant and the lubricating oil are insufficient. In order to prevent the above, similarly to the above, when the temperature Tcomp of the heat storage heat exchanger 8 is the lowest, as shown in FIG. 3, the second opening / closing valve 12 is temporarily opened immediately after the start of the operation of the compressor 1 (first The 2 on-off valve 33 is in the open state) to collect the refrigerant and the lubricating oil.

As described above, in this embodiment, even if the check valve 11 or the first opening / closing valve 12 leaks and refrigerant or lubricating oil stays in the heat storage heat exchanger 8, the low pressure It becomes possible to recover the lubricating oil from the return pipe 30 to the compressor 1 through the loss bypass pipe 31, and there is no risk of running out of refrigerant or lubricating oil. Moreover, the temperature Tcom detected in the compressor 1 is detected like the start-up after sleeping for a long time.
p, that is, the temperature of the heat storage heat exchanger 8 is the lowest, and the recovery operation is performed in a state in which the refrigerant and the lubricating oil are likely to accumulate in the heat storage heat exchanger 8. Useless collection operation can be prevented, and therefore noise is generated due to the operation of the first opening / closing valve 12, the life of the first opening / closing valve 12 is reduced, cooling capacity is reduced due to extra refrigerant bypass at the start of cooling operation or heating operation, and quick heating It is possible to solve the problem such as the decrease of

FIG. 4 shows a second embodiment, which has a structure in which a capillary tube 20 is used instead of the second opening / closing valve 33 in the first embodiment. In this case, the capillary tube
The size of 20 shall be selected so that it does not affect the capacity during defrosting and can fulfill the function of oil recovery. And this capillary tube 20
Preferably has a mounting structure as shown in FIG.
By connecting the outlet portion of the heat storage heat exchanger 8 to the return pipe 30 of the compressor 1 as described above, it is possible to reduce the refrigerant and lubricating oil from the bottom portion of the heat storage heat exchanger 8 as compared with the case of adopting the structure. The structure can be simplified. Since the other structure, control method and the like in this embodiment are the same as those in the first embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

(Effect of the invention) As described above, in the heat pump system according to the first aspect, when the refrigerant or the lubricating oil is likely to stay in the heat storage heat exchanger, the on-off valve is temporarily opened to perform the recovery operation. Since such a structure is adopted, it is possible to prevent the useless collection operation as in the past, and therefore noise is generated due to the useless operation of the opening / closing valve, the life of the opening / closing valve is shortened, and the cooling capacity is reduced by the extra refrigerant bypass. Therefore, it is possible to solve the problem such as the deterioration of the quick heating property.

The flow resistance used in the above can be inexpensively configured by elements such as a capillary tube and an electromagnetic on-off valve as described in the second aspect.

[Brief description of drawings]

FIG. 1 is a piping system diagram of an embodiment of a heat pump system of the present invention, FIG. 2 is a flow chart diagram showing a control example thereof, FIG. 3 is a time chart showing opening and closing operations of both on-off valves, and FIG. 2 is a piping system diagram showing a second embodiment, FIG. 5 is a structural schematic diagram of the main part thereof, and FIG. 6 is a piping system diagram showing a conventional example. 1 ... Compressor, 2 ... Four-way switching valve, 3 ... Outdoor heat exchanger, 5 ... Indoor heat exchanger, 6 ... Refrigerant piping, 8 ... Heat storage heat exchanger, 11 ... Check valve , 12 …… first on-off valve, 31 …… bypass piping, 33 …… second on-off valve, 34 …… first temperature sensor, 35 …… second temperature sensor, 36 …… third temperature sensor, 37 …… First on-off valve control unit (on-off valve control means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Morita 2 at 1000 Otani, Okamoto Town, Kusatsu City, Shiga Prefecture Daikin Industry Co., Ltd. Shiga Works (72) Inventor Hideo Nomura 1000 Otani, Okamoto Town, Kusatsu City, Shiga Prefecture No. 2 Shiga Works of Daikin Industries, Ltd.

Claims (2)

[Claims] 1. An indoor heat exchanger (5), an outdoor heat exchanger (3), a four-way switching valve (2), a pressure reducing mechanism (4) and a compressor (1) are connected by a refrigerant pipe (6). , A heat storage heat exchanger (8) for defrost operation, which stores the heat generated from the compressor (1), is arranged around the compressor (1), and the outdoor heat exchanger (3) and the pressure reducing mechanism (4) are arranged. And an outflow pipe (9) for connecting the refrigerant pipe (6) between the indoor heat exchanger (5) and the pressure reducing mechanism (4). An inflow pipe (10) connecting the (6) and the heat storage heat exchanger (8) is provided, and an on-off valve (12) is interposed in the inflow pipe (10), while heat is stored in the outflow pipe (9). A check valve (11) for flowing the refrigerant only in one direction from the heat exchanger (8) to the refrigerant pipe (6) is provided, and the heat storage heat exchanger (8) is introduced from the check valve (11). ) Side outflow pipe (9) and the return pipe (30) of the compressor (1), the bypass pipe (3) with the flow resistance (20) (33) interposed.
A heat pump system connected by 1), further comprising a first temperature sensor (34) for detecting the temperature of the heat storage heat exchanger (8) and a first temperature sensor (34) for detecting the temperature of the outdoor heat exchanger (3). 2 temperature sensor (35), 3rd temperature sensor (36) which detects the temperature of said indoor heat exchanger (5), and said 1st-3rd temperature sensor (34) (35) (36) said An on-off valve control means (37) for temporarily opening the on-off valve (12) after starting the compressor (1) when the temperature detected by the first temperature sensor (34) is the lowest is provided. Characteristic heat pump system. 2. The capillary tube (20) wherein the flow resistance is
Alternatively, the heat pump system according to claim 1, wherein the heat pump system is an electromagnetic on-off valve (33).