WO2008069092A1

WO2008069092A1 - Refrigeration device

Info

Publication number: WO2008069092A1
Application number: PCT/JP2007/073059
Authority: WO
Inventors: Satoshi Kawano; Shinya Matsuoka; Masahiro Oka
Original assignee: Daikin Industries, Ltd.
Priority date: 2006-12-05
Filing date: 2007-11-29
Publication date: 2008-06-12
Also published as: JP2008139001A; JP4274235B2

Abstract

An oil container (32), into which separated refrigeration machine oil flows and is contained, is connected to an oil separator (22). An oil outlet pipe (35), in which the refrigeration machine oil in the oil container (32) flows, is connected between the oil container (32) and a suction pipe (2b) of a compressor (21). An open/close valve (33) is provided in the oil outlet pipe (35). The surplus amount of refrigeration machine oil received in the compressor (21) is calculated based on the length of connection piping of a refrigeration circuit (20), and the open/close valve (33) is switched to an open state at predetermined intervals previously set according to the amount of the surplus oil.

Description

Specification

Refrigeration equipment

Technical field

TECHNICAL FIELD [0001] The present invention relates to a refrigeration apparatus, and particularly relates to measures for recovering excess oil of a compressor.

Conventionally, a refrigeration apparatus that performs a refrigeration cycle with a compressor is known! For example, the refrigeration apparatus of Patent Document 1 includes a refrigerant circuit that is a closed circuit in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected by a refrigerant pipe. In this refrigerant circuit, the high-pressure refrigerant discharged from the compressor returns to the compressor through the condensation process, the expansion process, and the evaporation process in order. Patent Document 1: JP 2001-304699 A

Disclosure of the invention

Problems to be solved by the invention

[0003] Incidentally, in the above-described compressor casing, generally, a refrigerating machine oil storage section for lubricating each sliding section is provided. In the compressor, a part of the refrigerating machine oil supplied to each sliding portion is discharged together with the compressed high-pressure refrigerant. Therefore, in general, an oil separator is provided in the discharge pipe of the compressor to separate the refrigerant and the refrigerating machine oil, and the separated refrigerating machine oil is returned to the suction side of the compressor.

However, in the hydraulic oil separator, since the refrigeration oil cannot be completely separated, the refrigeration oil that has not been separated flows through the refrigerant circuit together with the refrigerant. A part of the refrigerating machine oil flowing through the refrigerant circuit returns to the compressor together with the refrigerant, but the rest adheres to the refrigerant pipe and the like. Accordingly, since the amount of return of the refrigeration oil in the compressor is insufficient in this state and poor lubrication occurs, conventionally, the amount of refrigeration oil estimated in advance by the amount adhering to the refrigerant pipe or the like is stored in the compressor. .

[0005] Here, the amount of refrigerating machine oil to be accommodated in the compressor may be changed according to the total length of the refrigerant pipe of the refrigerating apparatus to be mounted, but this takes a lot of labor and labor, Generally, the total length of the refrigerant piping is set to be the same for the longest. However, if the compressor is mounted on a refrigeration apparatus of a type having a short refrigerant pipe length, excess refrigeration oil is generated. As a result, the amount of refrigerating machine oil that flows out of the compressor and adheres to the refrigerant piping and the like increases. As a result, there is a problem that the flow loss of the refrigerant in the refrigerant pipe increases and the load on the compressor increases.

[0006] The present invention has been made in view of such a point, and an object of the present invention is to recover surplus oil (surplus refrigerating machine oil) discharged from the compressor in a refrigerating apparatus having a compressor, This is to reduce the amount of oil adhering to the refrigerant piping.

Means for solving the problem

[0007] The first invention communicates with the compressor (21), an oil separator (22) connected to the discharge side of the compressor (21), and the oil separator (22). An oil sump container (32) for storing the refrigerating machine oil separated by the separator (22), and an on-off valve connected to the oil sump container (32) and the suction side of the compressor (21) (33) and a connecting pipe (35) for returning the refrigeration oil in the oil reservoir (32) to the suction side of the compressor (21), and a refrigerant circuit for performing a vapor compression refrigeration cycle (20) ) With a freezing device!

[0008] In the above invention, the refrigerant is circulated in the refrigerant circuit (20), and the vapor compression refrigeration cycle is performed. That is, the high-pressure refrigerant discharged from the compressor (21) returns to the compressor (21) again through the condensation process (heat radiation process), the expansion process, and the evaporation process in order. The compressor (21) contains refrigeration oil. Most of the refrigeration oil that flows out of the compressor (21) together with the refrigerant is separated by the oil separator (22). Slight refrigeration oil that has not been separated by the oil separator (22) flows together with the refrigerant, a part of it stays attached to the refrigerant pipe and the like, and the rest is sucked together with the refrigerant into the compressor (21).

[0009] All the refrigerating machine oil separated by the oil separator (22) is stored (collected) in an oil sump container (32). That is, most of the refrigerating machine oil flowing out from the compressor (21) is stored in the oil reservoir (32). In this state, the refrigerating machine oil is stored in the oil sump container (32) and does not return to the compressor (21). Therefore, the refrigerating machine oil in the compressor (21) is insufficient, resulting in poor lubrication. Therefore, by opening the on-off valve (33) of the connection pipe (35), the refrigeration oil in the oil sump container (32) flows to the suction side of the compressor (21). Therefore, adjust the open / close time of the open / close valve (33) during operation. As a result, the amount of refrigerating machine oil stored in the oil reservoir (32) is adjusted. Thereby, even if surplus refrigeration oil is stored in the compressor (21), the surplus oil can be stored (collected) in the oil reservoir (32). As a result, the amount of refrigerating machine oil flowing through the oil separator (22) and flowing through the refrigerant circuit (20) is suppressed, and the amount of oil adhering to the refrigerant pipe is reduced.

[0010] In a second aspect based on the first aspect, the oil separator (22) and the oil sump container (32) are arranged such that the refrigerating machine oil of the oil separator (22) flows therethrough (31 ). On the other hand, the oil reservoir container (32) is disposed below the oil separator (22).

[0011] In the above invention, as shown in FIG. 1, the oil sump container (32) is located under the oil separator (22)! /, So that it is separated by the oil separator (22). Refrigerating machine oil flows into the sump container (32) through its flow pipe (31) by its own weight. Therefore, it is not necessary to separately provide a means for allowing the refrigerating machine oil to flow from the oil separator (22) to the oil sump container (32). That is, the oil sump container (32) of the present invention is provided at a position where the refrigerating machine oil flows down from the oil separator (22) by its own weight.

[0012] In a third aspect based on the first aspect, a gas refrigerant is sealed in the oil sump container (32). The refrigerant circuit (20) has an on-off valve (36), one end communicating with the gas refrigerant space in the oil reservoir (32) and the other end on the on-off valve (35) in the connection pipe (35). 33) provided with a pressure reducing pipe (38) connected to the downstream of the oil sump container (32) for pressure reduction.

In the above invention, as shown in FIG. 2, the pressure reducing pipe (38) allows the oil reservoir (32) and the suction side of the compressor (21) to communicate with each other. Therefore, when the on-off valve (36) is opened, the gas refrigerant in the oil reservoir (32) flows to the suction side of the compressor (21) through the pressure reducing pipe (38), and the pressure in the oil reservoir (32) is reduced. The Then, the pressure inside the oil separator (22) is almost the same as the discharge pressure of the compressor (21), and a pressure difference is generated between the oil separator (22) and the oil reservoir (32). Due to this pressure difference, the refrigeration oil in the oil separator (22) flows into the oil reservoir (32). Thereby, the refrigerating machine oil separated by the oil separator (22) is stored (collected) in the oil sump container (32).

[0014] In a fourth aspect based on the first aspect, the surplus oil amount of the refrigerating machine oil stored in the compressor (21) is calculated based on the refrigerant pipe length of the refrigerant circuit (20), Control means (4) for opening the on-off valve (33) of the connection pipe (35) at predetermined intervals determined in advance according to the excess oil amount. 0).

[0015] In the above invention, the surplus oil amount of the refrigerating machine oil is calculated based on the refrigerant pipe length of the actual refrigerant circuit (20). The amount of refrigeration oil stored in the compressor (21) takes into account the amount of refrigeration oil adhering to the longest possible refrigerant piping length. Therefore, if the actual refrigerant pipe length is shorter than expected, an excess oil amount is generated by that short amount, and the excess oil amount is calculated from the actual refrigerant pipe length. Note that the refrigerant pipe length referred to here is, for example, as shown in FIG. 1, the pipe from the both ends of the indoor heat exchanger (26) to the second port of the four-way selector valve (23) and the expansion mechanism (25). The length of the pipe up to and the tube length of each heat exchanger (24, 26).

In the present invention, a predetermined time is set in advance according to the calculated surplus oil amount, and the on-off valve (33) is switched to the open state every predetermined time. When the on-off valve (33) opens, the refrigeration oil flows from the oil reservoir (32) through the connection pipe (35) into the compressor (21). As a result, the amount of refrigerating machine oil stored in the oil reservoir (32) is adjusted. That is, by changing the opening / closing timing of the on-off valve (33), the amount of refrigerating machine oil in the oil sump container (32) is adjusted, and the force S for storing the desired surplus oil amount in the sump container (32) can be achieved. .

[0017] According to a fifth invention, in the third invention, the surplus oil amount of the refrigeration oil stored in the compressor (21) is calculated based on a refrigerant pipe length of the refrigerant circuit (20), Control means (40) is provided for opening the on-off valve (33) of the connecting pipe (35) and closing the on-off valve (36) of the pressure reducing pipe (38) at predetermined time intervals determined in advance according to the surplus oil amount. /!

[0018] In the above invention, similarly to the above-described fourth invention, the surplus oil amount of the refrigerating machine oil is calculated based on the actual refrigerant pipe length of the refrigerant circuit (20). A predetermined time is preset according to the calculated surplus oil amount, and the on-off valve (33) of the connection pipe (35) is opened at every predetermined time, and the on-off valve (36) of the pressure reducing pipe (38) is opened. Switches to the closed state. That is, when the on-off valve (36) of the pressure reducing pipe (38) is opened, the on-off valve (33) of the connecting pipe (35) is closed, and when the on-off valve (36) of the pressure reducing pipe (38) is closed, the connecting pipe The open / close valve (33) of (35) opens.

[0019] When the on-off valve (36) of the pressure reducing pipe (38) is in the open state, the oil sump container (32) is depressurized, and the refrigerating machine oil of the oil separator (22) is stored in the oil sump container (32). It will be done. When the on-off valve (33) of the connection pipe (35) is in the open state, the oil sump container (32) is moved to the suction side of the compressor (21). Oil flows. That is, by changing the opening / closing timing of each on-off valve (33, 36), the inflow amount and outflow amount of refrigerating machine oil in the oil sump container (32) are adjusted. Therefore, surplus refrigeration oil can be stored in the oil reservoir (32).

[0020] In a sixth aspect based on the fourth or fifth aspect, the control means (40) is configured such that the refrigerating machine oil adheres to the refrigerant pipe according to the refrigerant pipe length of the refrigerant circuit (20). The amount is estimated, and the excess oil amount of the refrigerating machine oil stored in the compressor (21) is calculated from the estimated adhesion amount! /.

In the above invention, the amount of refrigeration oil attached to the refrigerant pipe is estimated from the actual refrigerant pipe length. Then, the difference between the estimated amount of adhesion and the amount of refrigeration oil adhering to the assumed longest refrigerant pipe length is calculated as the surplus of the refrigeration oil stored in the compressor (21).

[0022] In a seventh aspect based on the fourth or fifth aspect, the control means (40) is configured to lengthen the predetermined time as the calculated surplus oil amount increases. .

[0023] In the above invention, the larger the amount of excess oil stored in the oil reservoir (32), the longer the predetermined time. As the predetermined time becomes longer, the flow rate of the refrigerating machine oil from the oil sump container (32) decreases. That is, during the operation, the open time of the on-off valve (33) of the connection pipe (35) is shortened. This increases the amount of refrigerating machine oil stored in the oil reservoir (32).

[0024] In an eighth aspect based on the fourth or fifth aspect, the heat source side heat exchanger (24), the compressor (21), the oil separator (22), and the oil reservoir (32) are provided. It is equipped with a heat source unit (11) in which is stored and a usage unit (12) in which the usage-side heat exchanger (26) is stored. The refrigerant pipe length of the refrigerant circuit (20) is the length of the connecting pipe (2c, 2d) that connects the heat source unit (11) and the utilization unit (12).

[0025] In the above invention, in the refrigerant circuit (20), the refrigerant condensed (heat dissipated) in the heat source side heat exchanger (24) flows through the connecting pipe (2d) to the user side heat exchanger (26). ,Evaporate. The evaporated refrigerant returns to the compressor (21) through the connecting pipe (2c). Alternatively, in the refrigerant circuit (20), the refrigerant that has also discharged the compressor (21) force flows through the connecting pipe (2c) to the user-side heat exchanger (26), condenses (heatsinks), and then Heat source side heat exchanger through connecting pipe (2d) (24) To flow and evaporate.

[0026] Generally, the refrigeration apparatus (10) has a particular difference in the length of the connecting pipes (2c, 2d) depending on the installation location. That is, depending on the installation location of the refrigeration system (10), the connecting pipe (2c, 2d) becomes longer, and the amount of oil attached to the pipe increases accordingly. Therefore, in the present invention, the surplus oil amount of the refrigerating machine oil stored in the compressor (21) is calculated based on the length of the connecting pipe (2c, 2d). Therefore, the excess oil amount of refrigeration oil can be accurately grasped.

[0027] In a ninth aspect based on the eighth aspect, a plurality of the use units (12) are provided and connected in parallel to each other. The refrigerant pipe length of the refrigerant circuit (20) is the average length of the connecting pipes (2c, 2d) connecting the heat source unit (11) and each utilization unit (12).

[0028] In the above invention, the connecting pipes (2c, 2d) are branched and connected to each utilization unit (12). In this case, the length of the connecting pipe (2c, 2d) for each usage unit (12) differs depending on the installation location of the usage unit (12). Therefore, in the present invention, the surplus oil amount of the refrigeration oil accommodated in the compressor (21) is calculated based on the average length of the connecting pipes (2c, 2d) of each utilization unit (12). Therefore, the excess oil amount of refrigeration oil can be grasped without excess or deficiency.

The invention's effect

[0029] As described above, according to the present invention, the oil reservoir (32) in which the refrigerating machine oil separated by the oil separator (22) flows in and is stored, and the oil reservoir (32) A connecting pipe (35) is provided to return the refrigeration oil stored in the tank to the suction side of the compressor (21). Therefore, all the refrigerating machine oil that has flowed out of the compressor (21) and separated by the oil separator (22) is recovered in the oil sump container (32), and a part of the recovered refrigerating machine oil can be optionally added to the compressor ( 21). As a result, during operation, the surplus refrigeration oil can always be stored in the oil sump container (32), and the amount of refrigeration oil flowing through the refrigerant circuit (20) through the oil separator (22). Can suppress force S. Therefore, it is possible to prevent the refrigeration oil from adhering to the refrigerant pipe more than necessary. As a result, the flow loss of the refrigerant in the refrigerant pipe can be reduced, and the heat exchange efficiency of each heat exchanger (24, 26) can be improved.

[0030] According to the second invention, the oil sump container (32) is disposed below the oil separator (22). As a result, it is possible to force the refrigeration oil in the oil separator (22) to flow into the sump container (32) by its own weight. As a result, it is possible to reduce the cost and reduce the cost of the refrigeration apparatus, which does not require a separate means for injecting refrigeration oil from the oil separator (22) into the oil reservoir (32).

[0031] Further, according to the third invention, since the pressure reducing pipe (38) for reducing the pressure of the oil reservoir (32) is provided, the arrangement relationship between the oil reservoir (32) and the oil separator (22) is provided. Therefore, the refrigeration oil of the oil separator (22) can be introduced into the oil sump container (32). Therefore, the degree of freedom of installation of the oil sump container (32) can be increased, and the refrigeration apparatus can be simplified.

[0032] Further, according to the fourth, fifth and sixth inventions, the opening / closing timing of the on-off valve (33) is determined based on the surplus oil amount calculated according to the total length of the pipe. The surplus refrigeration oil can be reliably stored in the storage container (32). In other words, the amount of refrigeration oil necessary for lubrication of the compressor (21) can be reliably returned to the compressor (21). Accordingly, excess refrigeration oil can be recovered while preventing poor lubrication of the compressor (21).

[0033] Further, according to the seventh aspect of the invention, the larger the calculated excess oil amount, the longer the closing time of the on-off valve (33) of the connection pipe (35). In other words, the shorter the calculated excess oil amount, the shorter the closing time of the on-off valve (33) of the connecting pipe (35). As a result, the on-off valve (33) can be appropriately controlled according to the surplus oil amount, and surplus refrigerating machine oil can be reliably stored in the oil reservoir (32).

[0034] Further, according to the eighth invention, the surplus oil amount of the refrigeration oil is calculated based on the length of the connecting pipe (2c, 2d) connecting the heat source unit (11) and the utilization unit (12). As a result, the excess oil amount can be determined appropriately according to the installation location. Therefore, excess refrigeration oil in the compressor (21) can be reliably recovered.

[0035] According to the ninth invention, when a plurality of usage units (12) are connected in parallel, the freezing is performed based on the average length of the connecting pipes (2c, 2d) of each usage unit (12). The excess oil amount of machine oil was calculated. Therefore, the excess oil amount can be grasped without excess and deficiency, and excess refrigeration oil in the compressor (21) can be reliably recovered.

Brief Description of Drawings

FIG. 1 is a piping system diagram showing a configuration of an air conditioner according to Embodiment 1. FIG. 2 is a piping system diagram showing a configuration of an air conditioner according to Embodiment 2.

FIG. 3 is a piping system diagram showing a configuration of an air conditioner according to Embodiment 3. Explanation of symbols

10 Air conditioning equipment (refrigeration equipment)

11 Outdoor unit (heat source unit)

12 Indoor unit (Usage unit)

20 Refrigerant circuit

21 Compressor

22 Oil separator

24 Outdoor heat exchanger (heat source side heat exchanger)

26 Indoor heat exchanger (use side heat exchanger)

32 Oil sump container

33 On-off valve

35 Oil spill pipe (connection pipe)

36 On-off valve

38 Pressure reducer

40 Controller (Control means)

2c Communication gas piping (Communication piping)

2d Communication liquid piping (Communication piping)

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described in detail with reference to the drawings.

<< Embodiment 1 of the Invention >>

Embodiment 1 of the present invention will be described. As shown in FIG. 1, the air conditioner (10) of this embodiment includes a refrigerant circuit (20) that performs a vapor compression refrigeration cycle by circulating refrigerant. This air conditioner (10) constitutes a refrigeration apparatus according to the present invention.

[0040] The refrigerant circuit (20) includes a compressor (21), an oil separator (22), a four-way selector valve (23), an outdoor heat exchanger (24), and an expansion mechanism (25). And an indoor heat exchanger (26). The compressor (21) and the four-way selector valve (23) are connected to each other by refrigerant piping. It is.

[0041] Specifically, in the refrigerant circuit (20), the suction pipe (2b) of the compressor (21) is connected to the third port of the four-way switching valve (23). The discharge pipe (2a) of the compressor (21) is connected to the first port of the four-way selector valve (23) via the oil separator (22). The oil separator (22) is for separating the high-pressure refrigerant discharged from the compressor (21) and the refrigerating machine oil. The fourth port of the four-way selector valve (23) is connected to one end of the outdoor heat exchanger (24). The other end of the outdoor heat exchanger (24) is connected to one end of the indoor heat exchanger (26) via the expansion mechanism (25). The other end of the indoor heat exchanger (26) is connected to the second port of the four-way selector valve (23).

[0042] The compressor (21) is constituted by, for example, a hermetic high-pressure dome type scroll compressor. That is, the inside of the casing of the compressor (21) is a high pressure space. Although not shown, a refrigerating machine oil reservoir is provided at the bottom of the casing.

[0043] The outdoor heat exchanger (24) and the indoor heat exchanger (26) are so-called cross fin type fin 'and' tube heat exchangers. That is, in these heat exchangers (24, 26), a copper tube passes through a plurality of aluminum fins. An outdoor fan (27) and an indoor fan (28) are provided near the outdoor heat exchanger (24) and the indoor heat exchanger (26), respectively. The outdoor heat exchanger (24) constitutes a heat source side heat exchanger that exchanges heat between the refrigerant and outdoor air taken in by the outdoor fan (27). The indoor heat exchanger (26) constitutes a use side heat exchanger in which the refrigerant exchanges heat with the indoor air taken in by the indoor fan (28). The expansion mechanism (25) is composed of an expansion valve with variable opening.

Yes

[0044] The four-way selector valve (23) includes a first state (state indicated by a solid line in Fig. 1) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other. It is configured to switch to a second state (state indicated by a broken line in FIG. 1) in which the first port and the second port communicate and the third port and the fourth port communicate. In other words, in the refrigerant circuit (20), when the four-way selector valve (23) is in the first state, the refrigerant circulates in the cooling cycle, and the outdoor heat exchanger (24) serves as a condenser (radiator) for indoor heat exchange. Vessels (26) each function as an evaporator. In the refrigerant circuit (20), when the four-way selector valve (23) is in the second state, the refrigerant circulates in the heating cycle, the outdoor heat exchanger (24) serves as an evaporator, and the indoor heat exchanger (26) As a condenser (heatsink) It functions.

[0045] The refrigerant circuit (20) is provided with a surplus oil recovery mechanism (30) as a feature of the present invention. This surplus oil recovery mechanism (30) includes an oil inflow pipe (31), an oil sump container (32), an on-off valve (33), a capillary tube (34) and an oil outflow pipe (35)! /, The

[0046] The oil reservoir container (32) constitutes a sealed container, and is connected to the oil separator (22) by an oil inflow pipe (31). The oil sump container (32) is disposed below the oil separator (22). The oil sump container (32) is configured such that the refrigerating machine oil separated by the oil separator (22) flows through the oil inflow pipe (31) by its own weight. That is, the surplus oil recovery mechanism (30) is configured to recover all the refrigerating machine oil that has flowed out of the compressor (21) and separated by the oil separator (22) into the oil reservoir (32). . The oil inflow pipe (31) constitutes a flow pipe according to the present invention.

[0047] The oil outflow pipe (35) is connected to the bottom of the oil sump container (32) and to the middle of the suction pipe (2b) of the compressor (21) to constitute a connection pipe according to the present invention. Yes. The oil spill pipe (35) is provided with the on-off valve (33) and the capillary tube (34) in this order from the oil reservoir container (32) side. That is, in the surplus oil recovery mechanism (30), when the on-off valve (33) is opened, the refrigerating machine oil in the oil reservoir (32) passes through the oil outflow pipe (35) and the suction pipe (2b) of the compressor (21). ). Further, the refrigerating machine oil flowing through the oil outflow pipe (35) is adjusted to a predetermined flow rate by the capillary tube (34). The on-off valve (33) is composed of a solenoid valve.

[0048] The refrigeration system (10) includes the compressor (21), the oil separator (22), the four-way switching valve (23), the outdoor heat exchanger (24), the expansion mechanism (25), and the outdoor fan. And an outdoor unit (11) in which the surplus oil recovery mechanism (30) is stored, and an indoor unit (12) in which the indoor heat exchanger (27) and the indoor fan (28) are stored. . The outdoor unit (11) and the indoor unit (12) constitute a heat source unit and a utilization unit according to the present invention.

[0049] The outdoor unit (11) and the indoor unit (12) are connected by a communication gas pipe (2c) and a communication liquid pipe (2d) which are communication pipes. Specifically, the communication liquid pipe (2d) is connected between the expansion mechanism (25) and one end of the indoor heat exchanger (26). The communication gas pipe (2c) is connected between the other end of the indoor heat exchanger (26) and the second port of the four-way selector valve (23). That is, the communication gas pipe (2c) and the communication liquid pipe (2d) constitute a part of the refrigerant circuit (20). [0050] The air conditioner (10) includes a controller (40). The controller (40) is provided with a surplus oil amount calculation unit (41) and an on-off valve control unit (42).

[0051] The surplus oil amount calculation unit (41) manually inputs the total length of the communication gas pipe (2c) and the communication liquid pipe (2d) (hereinafter referred to as the communication pipe length). Then, the surplus oil amount calculation unit (41) calculates the surplus portion (hereinafter referred to as surplus oil amount) of the refrigeration oil in the compressor (21) based on the input connection pipe length. It is configured. That is, in this embodiment, the communication pipe length is the refrigerant pipe length according to the present invention. Specifically, the “surplus oil amount” is calculated by the following formula.

[0052] “Excess oil amount” = “Designed oil amount” “Actual oil amount”

Here, first, the amount of oil adhering to the refrigerant oil flowing out of the compressor (21) flows without being separated by the oil separator (22), and flows through the refrigerant pipes and the heat exchangers (24, 26). This is the estimated amount attached to the tube, and is estimated according to the communication pipe length. The “designed amount of attached oil” is the amount of attached oil estimated for the longest possible connecting pipe length. That is, it is a fixed value that is uniformly determined for any air conditioner. “Actual oil adhesion amount” is the amount of oil estimated with respect to the length of the connecting pipe in the actual air conditioner (10), and is the adhesion amount according to the present invention. Therefore, the “surplus oil amount” is calculated by the surplus oil amount calculation unit (41) by estimating the “actual machine attached oil amount” corresponding to the inputted actual connection pipe length.

The on-off valve control unit (42) stores the on-off valve (33) so that the refrigeration oil is stored in the oil reservoir container (32) by the amount of surplus oil calculated by the surplus oil amount calculation unit (41). ) Is controlled. Specifically, the on-off valve control unit (42) opens the on-off valve (33) every predetermined time T1 determined in advance according to the excess oil amount. The predetermined time T1 is set to become longer as the calculated excess oil amount increases. In other words, the surplus oil recovery mechanism (30) always flows refrigeration oil from the oil separator (22) into the oil sump container (32) during operation, but the refrigeration oil exceeding the surplus oil amount enters the sump container (32). Periodically, the oil reservoir (32) force refrigeration oil is returned to the compressor (21) so that the machine oil is not stored. Detailed control contents will be described later.

[0054] Driving operation

Next, the operation of the air conditioner (10) will be described. This air conditioner (10) is configured to be switchable between a cooling operation and a heating operation.

[0055] <Cooling operation>

In this cooling operation, in the refrigerant circuit (20), the refrigerant circulates in the direction indicated by the solid line arrow in FIG. 1, and a cooling cycle is performed. Specifically, the four-way selector valve (23) is set to the first state, and the opening degree of the expansion mechanism (25) is adjusted as appropriate. When the compressor (21) is driven in this state (when operation is started), the high-pressure refrigerant discharged from the compressor (21) to the discharge pipe (2a) passes through the oil separator (22). To the outdoor heat exchanger (24). In the outdoor heat exchanger (24), the high-pressure refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (24) is depressurized by the expansion mechanism (25) and then flows to the indoor heat exchanger (26). In the indoor heat exchanger (26), the low-pressure refrigerant absorbs heat from the indoor air and evaporates. The room air is cooled and supplied to the room. The low-pressure refrigerant evaporated in the indoor heat exchanger (26) is drawn into the compressor (21) from the suction pipe (2b).

[0056] <Heating operation>

In this heating operation, in the refrigerant circuit (20), the refrigerant circulates in the direction indicated by the dashed arrow in FIG. 1, and a heating cycle is performed. Specifically, the four-way selector valve (23) is set to the second state, and the opening degree of the expansion mechanism (25) is adjusted as appropriate. In this state, when the compressor (21) is driven, the compressor (21) force high-pressure refrigerant is discharged to the discharge pipe (2a), and then to the indoor heat exchanger (26) via the oil separator (22). Flowing. In the indoor heat exchanger (26), the high-pressure refrigerant releases heat to the indoor air and condenses. The room air is heated and supplied to the room. The refrigerant condensed in the indoor heat exchanger (26) is depressurized by the expansion mechanism (25) and then flows to the outdoor heat exchanger (24). In the outdoor heat exchanger (24), the low-pressure refrigerant absorbs heat from the outdoor air and evaporates. The low-pressure refrigerant evaporated in the outdoor heat exchanger (24) is sucked into the compressor (21) through the suction pipe (2b).

First, before the operation is started, the on-off valve (33) is set to the closed state, and the communication pipe length is manually input to the surplus oil amount calculation unit (41). Then, the surplus oil amount calculation unit (41) calculates the surplus oil amount.

[0058] Next, when the operation is started, the refrigeration oil flows out of the compressor (21) together with the refrigerant, and most of the oil is separated by the oil separator (22). The separated refrigeration oil flows into the oil due to its own weight. It flows into the sump container (32) through the pipe (31). A small amount of refrigeration oil that has not been separated by the oil separator (22) flows through the refrigerant circuit (20) together with the refrigerant. Part of the refrigeration oil stays attached to the communication pipes (2c, 2d) and the tubes of the heat exchangers (24, 26), and the rest returns to the compressor (21) together with the refrigerant.

[0059] When a predetermined time T1 has elapsed from the start of operation, the on-off valve control section (42) switches the on-off valve (33) to an open state. During this predetermined time T1, the amount of refrigerating machine oil stored in the oil sump container (32) increases. Then, when a predetermined time T2 has elapsed since switching to the open state, the on-off valve control section (42) closes the on-off valve (33) again. While this on-off valve (33) is open (during a predetermined time T2), refrigeration oil flows from the oil separator (22) into the oil reservoir (32), while refrigeration oil from the oil reservoir (32). Flows into the suction pipe (2b) of the compressor (21) at a predetermined flow rate. Subsequently, when a predetermined time T1 elapses after the on-off valve (33) is closed, the on-off valve (33) is switched to the open state again for the predetermined time T2, and this on-off control is repeated. As a result, surplus refrigeration oil is always stored in the oil sump container (32). Further, since the predetermined time T1 becomes longer as the calculated surplus oil amount increases, the surplus refrigerating machine oil is reliably stored in the oil sump container (32).

[0060] Effect of Embodiment 1

According to the present embodiment, the oil reservoir (32) in which the refrigerating machine oil separated by the oil separator (22) flows in and stored, and the refrigerating machine oil stored in the oil reservoir (32) are compressed by the compressor ( An oil outflow pipe (35) is provided to return to the suction pipe (2b) of 21). Therefore, all the refrigerating machine oil flowing out from the compressor (21) and separated by the oil separator (22) is recovered in the oil reservoir (32), and a part of the recovered refrigerating machine oil is optionally compressed. Return to (21). As a result, during operation, surplus refrigeration oil can always be stored in the oil reservoir (32), and the amount of refrigeration oil flowing through the refrigerant circuit (20) through the oil separator (22) can be reduced. Can be suppressed. Therefore, it is possible to prevent the refrigeration oil from adhering to the connecting pipe (2c, 2d) and the tubes of the heat exchangers (24, 26) more than necessary. As a result, the flow loss of the refrigerant in the refrigerant pipe can be reduced, and the heat exchange efficiency of each heat exchanger (24, 26) can be improved.

[0061] Further, the oil sump container (32) can be arranged below the oil separator (22), and the refrigerating machine oil of the oil separator (22) can be guided to the sump container (32) by its own weight. Therefore, the oil separator (22) Therefore, surplus refrigeration oil can be recovered in the oil sump container (32) with a simple configuration without separately providing power means for introducing the refrigeration oil into the oil sump container (32). As a result, a compact and low-cost air conditioner (10) can be provided.

[0062] In addition, since the amount of oil attached to the actual machine varies greatly depending on the length of the connecting pipe, the amount of oil attached to the actual machine is estimated based on the length of the connecting pipe, so that the excess oil amount is calculated. Accurate extra power Can understand IJ oil amount. Since the opening / closing timing of the on-off valve (33) is determined based on the calculated surplus oil amount, the refrigerating machine oil necessary for lubrication is securely stored while the surplus refrigerating machine oil is securely stored in the oil reservoir (32). Can be reliably returned to the compressor (21). Therefore, the force S can be used to recover excess refrigerating machine oil while preventing poor lubrication of the compressor (21).

[0063] Embodiment 2 of the Invention

Embodiment 2 of the present invention will be described. As shown in FIG. 2, the air conditioner (10) of the present embodiment is obtained by changing the configuration of the excess oil recovery mechanism (30) to the above-described first embodiment. That is, in this embodiment, the pressure reducing pipe (38) is provided in the surplus oil recovery mechanism (30) of the first embodiment.

[0064] One end of the pressure reducing pipe (38) is connected to the oil reservoir (32) and communicates with a gas space (refrigerant gas space) in the oil reservoir (32). The other end of the pressure reducing pipe (38) is connected to the downstream side of the capillary tube (34) in the oil outflow pipe (35) and communicates with the suction side of the compressor (21). The pressure reducing pipe (38) is provided with an on-off valve (36) and a capillary tube (37) in order from the oil reservoir (32) side. The on-off valve (36) is a solenoid valve.

That is, in the surplus oil recovery mechanism (30) of the present embodiment, the open / close valve (36) of the pressure reducing pipe (38) is opened so that the gas refrigerant in the oil sump container (32) is compressed by the compressor (21). The oil reservoir (32) is depressurized by being sucked into the suction pipe (2b). As a result, the pressure in the oil separator (22) is almost the same as the discharge pressure of the compressor (21), so there is a pressure difference between the oil separator (22) and the oil reservoir (32). Arise. Due to this pressure difference, the refrigeration oil in the oil separator (22) flows into the oil reservoir (32) through the oil inflow pipe (31).

[0066] Thus, in this embodiment, the refrigerating machine oil separated by the oil separator (22) is taken up by its own weight. Even if it is not introduced into the oil sump container (32), the refrigerating machine oil in the oil separator (22) must be reliably recovered in the sump container (32) by opening the on-off valve (36) of the pressure reducing pipe (38). Power S can be. Therefore, as in the first embodiment, the oil sump container (32) may be disposed on the side or upper side of the oil separator (22) which does not need to be disposed below the oil separator (22). That is, the degree of freedom in installing the oil sump container (32) is increased, and the air conditioner (10) can be made compact.

[0067] The controller (40) of the present embodiment performs the following control operation.

[0068] The surplus oil amount calculation unit (41) calculates the “surplus oil amount” based on the connection pipe length manually input in the same manner as in the first embodiment. On the other hand, the on-off valve control section (42) alternately opens and closes the on-off valve (33) of the oil outflow pipe (35) and the on-off valve (36) of the pressure reducing pipe (38). Specifically, the on-off valve control unit (42) opens the on-off valve (33) of the oil outflow pipe (35) every predetermined time T1 set in advance according to the excess oil amount, as in the first embodiment. Put it in a state. The on-off valve controller (42) closes the on-off valve (36) of the pressure reducing pipe (38) when the on-off valve (33) of the oil outflow pipe (35) is opened, and When the on-off valve (33) is closed, the open / close valve (36) of the pressure reducing pipe (38) is opened. That is, the on-off valve control section (42) closes the on-off valve (36) of the pressure reducing pipe (38) every predetermined time T1 set in advance according to the excess oil amount.

[0069] Driving action

Next, the operation of the surplus oil recovery mechanism (30) and the control operation of the controller (40) of this embodiment will be described. The refrigerant flow in the cooling operation and the heating operation is the same as that in the first embodiment.

[0070] First, before the operation is started, the on-off valve (33) of the oil outflow pipe (35) is set to the closed state and the on-off valve (36) of the pressure reducing pipe (38) is set to the open state, so The length is manually input to the surplus oil amount calculation unit (41). Then, the surplus oil amount is calculated in the surplus oil amount calculation unit (41).

Next, when the operation is started, the refrigeration oil flows out of the compressor (21) together with the refrigerant, and most of the oil is separated by the oil separator (22). On the other hand, the gas refrigerant in the oil reservoir (32) is sucked into the compressor (21) through the pressure reducing pipe (38) and the oil outflow pipe (35). As a result, the pressure in the oil sump container (32) is reduced.

[0072] The refrigerating machine oil separated by the oil separator (22) is the pressure between the oil separator (22) and the oil reservoir (32). Due to the force difference, the oil flows into the oil reservoir (32) through the oil inflow pipe (31). A small amount of refrigeration oil that has not been separated by the oil separator (22) flows through the refrigerant circuit (20) together with the refrigerant. A part of the refrigerating machine oil adheres to the refrigerant piping and the tubes of the heat exchangers (24, 26), and the rest returns to the compressor (21) together with the refrigerant.

[0073] When a predetermined time T1 has elapsed from the start of operation, the on-off valve controller (42) causes the on-off valve (36) of the pressure reducing pipe (38) to be closed and the on-off valve (33) of the oil outflow pipe (35) to be closed. Are each switched to the open state. During this predetermined time T1, the amount of refrigerating machine oil stored in the oil sump container (32) increases. When a predetermined time T2 elapses after the on-off valves (33, 36) are switched, the on-off valve control unit (42) again closes the on-off valve (33) of the oil outflow pipe (35), and the pressure reducing pipe. The on-off valve (36) of (38) is switched to the open state. While the on-off valve (33) of the oil outflow pipe (35) is open (during the predetermined time T2), the oil reservoir (32) is also supplied with the refrigerating machine oil at the predetermined flow rate and the suction pipe (2b ). At that time, the same amount of refrigerating machine oil as that of the refrigerating machine oil flows into the oil sump container (32) from the oil separator (22). In this way, the opening / closing of the on-off valves (33, 36) is repeated. As a result, surplus refrigerating machine oil is always stored in the oil sump container (32).

[0074] Effect of Embodiment 2

According to the present embodiment, since the pressure reducing pipe (38) is provided in the surplus oil recovery mechanism (30), the oil separator that has no problem with the positional relationship between the oil separator (22) and the oil reservoir (32) is provided. The refrigerating machine oil separated in (22) can be recovered in the oil reservoir (32). Therefore, the installation restriction of the oil sump container (32) can be relaxed, and the air conditioner (10) can be made compact.

[0075] In addition, since the opening / closing timing of the opening / closing valve (36) of the pressure reducing pipe (38) is determined based on the surplus oil amount calculated according to the communication pipe length, the oil reservoir (32) The surplus refrigeration machine oil can be stored in the tank. Other configurations, operations, and effects are the same as those in the first embodiment.

<< Embodiment 3 of the Invention >>

Embodiment 3 of the present invention will be described. As shown in FIG. 3, the air conditioner (10) of the present embodiment includes a plurality of indoor units (12) in the first embodiment (in this embodiment, 2 Stand) and connected in parallel to each other. Further, the refrigerant circuit (20) of the present embodiment includes an outdoor expansion mechanism (25a) and an indoor expansion mechanism (25b) instead of the expansion mechanism (25) in the first embodiment! It is.

[0077] Specifically, the communication gas pipe (2c) and the communication liquid pipe (2d) extending from the outdoor unit (11) are branched and connected to each indoor unit (12). The outdoor expansion mechanism (25a) is housed in the outdoor unit (11) and is connected between the outdoor heat exchanger (24) and the communication liquid pipe (2d). The indoor expansion mechanism (25b) is housed in each indoor unit (12) and is connected between the indoor heat exchanger (26) and the communication liquid pipe (2d).

In this case, in the cooling operation, the outdoor expansion mechanism (25a) is set to a fully open state, and the opening degree of each indoor expansion mechanism (25b) is appropriately adjusted. In this cooling operation, the refrigerant condensed (dissipated) in the outdoor heat exchanger (24) is diverted to each indoor unit (12) through the connecting liquid pipe (2d), and then decompressed by the indoor expansion mechanism (25b). Evaporates in the indoor heat exchanger (26). In the heating operation, each indoor expansion mechanism (25b) is set to a fully open state, and the opening degree of the outdoor expansion mechanism (25a) is adjusted as appropriate. In this heating operation, the refrigerant discharged from the compressor (21) is diverted to each indoor unit (12) through the communication gas pipe (2c) and condensed (radiated) by the indoor heat exchanger (26), and then contacted. Flows into the liquid pipe (2d). Other driving operations are the same as those in the first embodiment.

[0079] In the controller (40) of the present embodiment, the surplus oil amount calculation unit (41) is manually input the average length of the communication pipe length of each indoor unit (12). The surplus oil amount calculation unit (41) is configured to calculate the “surplus oil amount” based on the input average length. In other words, the “actual oil adhesion amount” corresponding to the average length of the communication pipe length is estimated, and the “surplus oil amount” is calculated.

[0080] In the present embodiment, the force with different connecting pipe lengths for each indoor unit (12) calculates the surplus oil amount based on the average length, so that the surplus oil amount can be grasped without excess or deficiency. . Accordingly, surplus refrigeration oil can be reliably recovered in the oil reservoir (32). Other configurations, operations, and effects are the same as those in the first embodiment.

[0081] << Other Embodiments >>

According to each of the above embodiments, the following configuration may be used.

[0082] For example, in each of the above embodiments, when the on-off valve (33) of the oil outflow pipe (35) is open. The interval (predetermined time T2) is a fixed time, but it may be changed according to the amount of surplus oil calculated. In this case, the predetermined time 2 is shortened as the excess oil amount increases.

[0083] In the second embodiment, the opening / closing valve (36) of the pressure reducing pipe (38) may be always opened when the opening / closing valve (36) is switched to the closed state every predetermined time T1.

[0084] In each of the above embodiments, the excess oil amount is calculated based on the communication pipe length. However, the present invention is not limited to this, and the connection pipe length and the tube length of each heat exchanger (24, 26) are calculated. The surplus oil amount may be calculated based on the total length. In this case, a more appropriate amount of oil attached to the actual machine is estimated, and the excess oil amount can be ascertained reliably. Of course, other pipe lengths may be taken into account.

[0085] Also, when a plurality of indoor units (12) are provided in parallel in the second embodiment, as in the third embodiment, based on the average length of the connecting pipe lengths for each indoor unit (12). The surplus oil amount may be calculated.

[0086] Further, in each of the above-described embodiments, instead of the force that uses an electromagnetic valve for each on-off valve (33, 36), a flow rate adjusting valve capable of adjusting the opening degree may be used. In that case, the capillary tube (34, 37) is omitted.

Further, in each of the above embodiments, the air conditioner has been described. However, the present invention is not limited thereto, and the present invention is a refrigeration apparatus including a refrigerant circuit in which an oil separator is connected to the discharge side of the compressor. As long as it is (for example, a refrigerator), it may be applied to anything.

[0088] The above embodiment is essentially a preferable example, and the present invention and its applied products are described.

, Or not intended to limit the scope of its use.

Industrial applicability

[0089] As described above, the present invention is useful as a refrigeration apparatus including a refrigerant circuit having an oil separator connected to the discharge side of a compressor.

Claims

The scope of the claims

[1] The compressor (21), the oil separator (22) connected to the discharge side of the compressor (21), and the oil separator (22) communicated with the oil separator (22). An oil sump container (32) for storing the separated refrigerating machine oil; and an open / close valve (33) connected to the oil sump container (32) and the suction side of the compressor (21). And a connection pipe (35) for returning the refrigeration oil in the oil reservoir (32) to the suction side of the compressor (21), and a refrigerant circuit (20) for performing a vapor compression refrigeration cycle. , Ru

A refrigeration apparatus characterized by that.

[2] In claim 1,

The oil separator (22) and the oil reservoir (32) are connected by a circulation pipe (31) through which the refrigeration oil of the oil separator (22) flows,

The refrigeration apparatus, wherein the oil sump container (32) is disposed below the oil separator (22).

[3] In claim 1,

The oil sump container (32) is filled with a gas refrigerant,

The refrigerant circuit (20) has an on-off valve (36), one end communicating with the gas refrigerant space in the oil reservoir (32) and the other end of the on-off valve (33) in the connection pipe (35). A pressure reducing pipe (38) for reducing the pressure in the oil sump container (32) connected downstream is provided.

A refrigeration apparatus characterized by that.

[4] In claim 1,

Based on the refrigerant pipe length of the refrigerant circuit (20), the surplus oil amount of the refrigeration machine oil accommodated in the compressor (21) is calculated, and the predetermined amount of time predetermined according to the surplus oil amount is calculated. It is equipped with control means (40) that opens the on-off valve (33) of the connecting pipe (35).

A refrigeration apparatus characterized by that.

[5] In claim 3,

Based on the refrigerant pipe length of the refrigerant circuit (20), the surplus oil amount of the refrigeration machine oil accommodated in the compressor (21) is calculated, and the predetermined amount of time predetermined according to the surplus oil amount is calculated. Control means for opening the on-off valve (33) of the connecting pipe (35) and closing the on-off valve (36) of the pressure reducing pipe (38) (40) with

A refrigeration apparatus characterized by that.

[6] In claim 4 or 5,

The control means (40) estimates the amount of attachment of refrigeration oil to the refrigerant pipe according to the refrigerant pipe length of the refrigerant circuit (20), and stores it in the compressor (21) from the estimated amount of attachment. It is configured to calculate the excess oil amount of the refrigerating machine oil

A refrigeration apparatus characterized by that.

[7] In claim 4 or 5,

The control means (40) is configured to increase the predetermined time as the calculated surplus oil amount increases.

A refrigeration apparatus characterized by that.

[8] In claim 4 or 5,

A heat source unit (11) in which the heat source side heat exchanger (24), the compressor (21), the oil separator (22), and the oil sump container (32) are housed, and a use side heat exchanger (26) And a use unit (12) in which is stored,

The refrigerant pipe length of the refrigerant circuit (20) is the length of the connecting pipe (2c, 2d) connecting the heat source unit (11) and the utilization unit (12).

A refrigeration apparatus characterized by that.

[9] In claim 8,

A plurality of the use units (12) are provided and connected in parallel to each other,

The refrigerant pipe length of the refrigerant circuit (20) is the average length of the connecting pipes (2c, 2d) connecting the heat source unit (11) and each utilization unit (12).

A refrigeration apparatus characterized by that.