GB2588714A

GB2588714A - Refrigeration cycle device

Info

Publication number: GB2588714A
Application number: GB2016438.0A
Authority: GB
Inventors: Nakagawa Masahiko; Arii Yusuke; Saikusa Tetsuji
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2018-04-23
Filing date: 2018-04-23
Publication date: 2021-05-05
Anticipated expiration: 2038-04-23
Also published as: GB2588714A8; JP6896165B2; GB2588714B; GB202016438D0; JPWO2019207619A1; GB2588714A9; WO2019207619A1

Abstract

This refrigeration cycle device is provided with: a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in the stated order by refrigerant piping; and an expansion valve control unit that adjusts the opening degree of the expansion valve. The expansion valve control unit is configured so as to: store a first table in which there is defined a freezing performance in which the range of performance of the evaporator is quantified, as well as a relationship between the expansion valve opening degree and a plurality of types of refrigerant; and determine, on the basis of the first table, an optimal usage range from an upper limit to a lower limit of the expansion valve opening degree that correspond to the refrigerant used.

Description

DESCRIPTION Title of Invention

REFRIGERATION CYCLE APPARATUS

Technical Field

[0001] The present disclosure relates to a refrigeration cycle apparatus that includes an expansion-valve control unit that adjusts the opening degree of an expansion valve. Background Art [0002] A technique has been disclosed in which the opening degree of an electronic expansion valve is able to be adjusted over use ranges for a plurality of types of refrigerants (for example, see Patent Literature 1). In the technique disclosed in Patent Literature 1, the type of refrigerant is automatically determined on the basis of the degree of discharge superheat and the degree of suction superheat in a trial run.

Citation List Patent Literature [0003] Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2017-141998

Summary of Invention

Technical Problem [0004] However, the refrigeration capacity of an evaporator for which an expansion valve is used is varied even with a single type of refrigerant. In some technique, in the case where an abnormality occurs in detection by a temperature sensor at an outlet of an evaporator or in other cases, an opening degree of an expansion valve that is outside a proper use range of the capacity of the evaporator may be output. In the case where an opening degree of the expansion valve that exceeds the range of the capacity of the evaporator is output, a liquid return operation occurs. As a result, a compressor may break down. Furthermore, in the case where an opening degree of the expansion valve that is lower than the capacity of the evaporator is output, the temperature at an inlet of the compressor increases and a superheat operation thus occurs. As a result, the compressor may break down.

[0005] The present disclosure is designed to solve the above-mentioned problems, and an object of the present disclosure is to provide a refrigeration cycle apparatus that is able to set a proper use range from the upper limit to the lower limit of an opening degree of an expansion valve that corresponds to the type of refrigerant used and the refrigeration capacity of an evaporator for which the expansion valve is used, prevent a liquid return operation and a superheat operation from occurring, and prevent a compressor from breaking down.

Solution to Problem [0006] A refrigeration cycle apparatus according to an embodiment of the present disclosure includes a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order by a refrigerant pipe, and an expansion-valve control unit configured to adjust an opening degree of the expansion valve. The expansion-valve control unit is configured to store a first table that defines a relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and the opening degree of the expansion valve and set, with reference to the first table, a proper use range from an upper limit to a lower limit of the opening degree of the expansion valve corresponding to a refrigerant that is used.

Advantageous Effects of Invention [0007] In a refrigeration cycle apparatus according to an embodiment of the present disclosure, an expansion-valve control unit stores a first table that defines a relationship between a refrigeration capacity representing a capacity range of an evaporator as a numerical value, a plurality of types of refrigerants, and an opening degree of an expansion valve and sets, with reference to the first table, a proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used. Thus, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the type of the refrigerant used and the refrigeration capacity of the evaporator for which the expansion valve is used can be set. Consequently, a liquid return operation and a superheat operation can be prevented, and a compressor can thus be prevented from breaking down.

Brief Description of Drawings

[0008] [Fig. 1] Fig. 1 is a refrigerant circuit diagram illustrating a refrigeration cycle apparatus according to Embodiment 1 of the present disclosure.

[Fig. 2] Fig. 2 is a block diagram illustrating a configuration of an expansion-valve control unit according to Embodiment 1 of the present disclosure.

[Fig. 3] Fig. 3 is a functional block diagram illustrating functions of the expansion-valve control unit according to Embodiment 1 of the present disclosure.

[Fig. 4] Fig. 4 is an explanatory diagram illustrating a first table according to Embodiment 1 of the present disclosure.

[Fig. 5] Fig. 5 is an explanatory diagram illustrating a second table according to Embodiment 1 of the present disclosure.

[Fig. 6] Fig. 6 is an explanatory diagram illustrating a state in which a proper use range is set with reference to the first table according to Embodiment 1 of the present disclosure.

[Fig. 7] Fig. 7 is an explanatory diagram illustrating the set proper use range according to Embodiment 1 of the present disclosure.

[Fig. 8] Fig. 8 is a flowchart illustrating a control routine for setting an opening degree of an expansion valve according to Embodiment 1 of the present disclosure. Description of Embodiments [0009] Hereinafter, an embodiment of the present disclosure will be explained with reference to drawings. In the drawings, parts referred to by the same reference signs are the same or correspond to each other, and the same applies throughout the specification. Furthermore, in cross-section diagrams, hatching is omitted in an appropriate manner in view of visibility. Moreover, forms of components described herein are merely examples and the form of components are not limited to the forms described herein.

[0010] Embodiment 1 <Refrigeration Cycle Apparatus 100> Fig. 1 is a refrigerant circuit diagram illustrating a refrigeration cycle apparatus 100 according to Embodiment 1 of the present disclosure.

[0011] As illustrated in Fig. 1, the refrigeration cycle apparatus 100 includes a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4. The compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4 are connected in order by a refrigerant pipe to form a refrigerant circuit. Refrigerant that has flowed out of the evaporator 4 is suctioned into the compressor 1 and turns into high-temperature, high-pressure refrigerant. The high-temperature, high-pressure refrigerant is condensed by the condenser 2 and turns into liquid refrigerant. The liquid refrigerant is decompressed and expanded by the expansion valve 3 and turns into low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant is subjected to heat exchange at the evaporator 4.

[0012] The refrigeration cycle apparatus 100 may be, for example, an air-conditioning apparatus, a freezing apparatus, or a water heater.

[0013] The expansion valve 3 is a flow rate control valve. The expansion valve 3 decompresses and expands refrigerant. The expansion valve 3 is configured to be an electronic expansion valve. Thus, the expansion valve 3 includes an expansion-valve control unit 5 in an integrated manner. The expansion valve 3 and the expansion-valve control unit 5 communicate with each other via a communication line 6 in a wired or wireless manner. The opening degree of the expansion valve 3 is adjusted in accordance with an instruction from the expansion-valve control unit 5.

[0014] <Functional Configuration of Expansion-valve Control Unit 5> Fig. 2 is a block diagram illustrating a configuration of an expansion-valve control unit according to Embodiment 1 of the present disclosure. Fig. 3 is a functional block diagram illustrating functions of the expansion-valve control unit 5 according to Embodiment 1 of the present disclosure. A function of the expansion-valve control unit 5 of setting the opening degree of the expansion valve 3 within a proper use range, which is characteristic of Embodiment 1 described later, will be explained. With other functions of the expansion-valve control unit 5, the opening degree of the expansion valve 3 at the time of operation of the refrigeration cycle apparatus 100 and other values may be appropriately controlled depending on operation conditions.

[0015] As illustrated in Fig. 2, the expansion-valve control unit 5 is a processing circuit that includes a microcomputer including a CPU, a memory such as a ROM and a RAM, and an input-output device such as an input-output port.

[0016] As illustrated in Fig. 3, the expansion-valve control unit 5 is configured to be a processing circuit including an input part 5a, a storing part 5b, a range setting part 5c, an opening-degree setting part 5d, and a control part 5e.

[0017] The input part 5a receives a purpose, horsepower, and a refrigerant of the refrigeration cycle apparatus 100, which are used as use information, input by a setting person. The input part 5a may receive the use information via a switch provided in the input part 5a or via a communication line or a connected storage medium.

[0018] The storing part 5b includes storage media such as a ROM, a RAM, and a flash memory. The storing part 5b stores a first table and a second table.

[0019] Fig. 4 is an explanatory diagram illustrating a first table according to Embodiment 1 of the present disclosure. As illustrated in Fig. 4, the first table defines the relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and an opening degree of the expansion valve. That is, by checking a refrigerant that is used and a refrigeration capacity against the first table, a proper use range from the upper limit to the lower limit of an opening degree of the expansion valve corresponding to the refrigerant used can be set.

[0020] Fig. 5 is an explanatory diagram illustrating a second table according to Embodiment 1 of the present disclosure. The second table defines the relationship between a purpose, horsepower, and a capacity range of the evaporator That is, by checking the purpose and the horsepower input by a setting person against the second table, a capacity range of the evaporator corresponding to the purpose and the horsepower used can be set.

[0021] The range setting part 5c performs processing for checking the purpose and the horsepower input into the input part 5a against the second table and setting the capacity range of the evaporator corresponding to the input purpose and the input horsepower As illustrated in Fig. 5, in the case where, out of cooling and freezing, cooling is input as the purpose and the horsepower is set to 10, the range setting part 5c substitutes the information for corresponding values in the second table. In the second table, vertical fields indicate purposes and horizontal fields indicate horsepower Thus, when the purpose and the horsepower are input, the upper limit of the capacity of the evaporator is set to 25.0 and the lower limit of the capacity of the evaporator is set to 10.0, as indicated in shaded intersections.

[0022] The opening-degree setting part 5d performs processing for checking the capacity range of the evaporator set by the range setting part Sc and the refrigerant input to the input part 5a against the first table and setting a proper use range from the upper limit to the lower limit of an opening degree of the expansion valve corresponding to the refrigerant used.

[0023] Fig. 6 is an explanatory diagram illustrating a state in which a proper use range is set with reference to the first table according to Embodiment 1 of the present disclosure.

As illustrated in Fig. 6, the opening-degree setting part 5d inputs the capacity upper limit, 25.0, and the capacity lower limit, 10.0, which represent the capacity range of the evaporator set by the range setting part Sc, and the refrigerant used, R410A, into the first table. The first table includes a vertical scale indicating a refrigeration capacity, which represents a capacity range of the evaporator as a numerical value, and a horizontal scale indicating an opening degree of the expansion valve. Characteristic lines corresponding to a plurality of types of refrigerants are indicated on the first table. Thus, when the capacity upper limit, 25.0, the capacity lower limit, 10.0, and the refrigerant used, R410A, are input, a capacity range of the evaporator corresponding to the characteristic line for R410A is set, as indicated by a shaded part. By drawing straight lines straight down from the upper limit value and the lower limit value of the capacity range of the evaporator to the scale of the opening degree of the expansion valve, a proper use range from the upper limit to the lower limit of the opening degree of the expansion valve is set. The proper use range of R41 OA is set between the maximum opening degree, 800, and the minimum opening degree, 450, as illustrated in Fig. 7 described below.

[0024] The control part 5e performs processing for controlling the opening degree of the expansion valve 3 within the proper use range of the opening degree of the expansion valve set by the opening-degree setting part 5d. That is, the control part 5e performs control in such a manner that the opening degree of the expansion valve 3 falls within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve set by the opening-degree setting part 5d, and thus controls the opening degree of the expansion valve 3 not to be outside the proper use range.

[0025] Fig. 7 is an explanatory diagram illustrating a proper use range set by the opening-degree setting part 5d according to Embodiment 1 of the present disclosure. As illustrated in Fig. 7, the opening-degree setting part 5d sets the proper use range for R410A from the maximum opening degree, 800, to the minimum opening degree, 450.

The values illustrated in Fig. 7 are stored in the storing part 5b. Accordingly, the control part 5e controls the opening degree of the expansion valve 3 within the range from the maximum opening degree, 800, to the minimum opening degree, 450. Details of how the control part 5e controls the opening degree of the expansion valve depending on the operating state of the refrigeration cycle apparatus 100 will be omitted. During normal operation of the refrigeration cycle apparatus 100, the control part 5e controls the opening degree of the expansion valve 3 within the range from the maximum opening degree, 800, to the minimum opening degree, 450, with reference to the table illustrated in Fig. 7 stored in advance in the storing part 5b as a result of previous execution of a routine, which will be described later.

[0026] <Control Routine for Setting Opening Degree of Expansion Valve> Fig. 8 is a flowchart illustrating a control routine for setting an opening degree of the expansion valve performed by the expansion-valve control unit 5 according to Embodiment 1 of the present disclosure. The routine illustrated in Fig. 8 is performed when the refrigeration cycle apparatus 100 operates for the first time, when the refrigeration cycle apparatus 100 is reset, or at other timings.

[0027] When the refrigeration cycle apparatus 100 operates for the first time, when the refrigeration cycle apparatus 100 is reset, or at other timings, the routine starts.

[0028] In step S101, the input part 5a of the expansion-valve control unit 5 determines whether a purpose, horsepower, and the type of refrigerant are input. In the case where it is determined in step S101 that a purpose, horsepower, and the type of refrigerant are input, the routine proceeds to step S102. In the case where a purpose, horsepower, and the type of refrigerant are not input in step 5101, the routine temporarily ends.

[0029] In step S102, the range setting part 5c of the expansion-valve control unit 5 sets a capacity range of the evaporator in accordance with the purpose and the horsepower, with reference to the second table stored in the storing part 5b. Details of the processing are as explained above for the range setting part 5c. When the processing of step S102 ends, the routine proceeds to step S103.

[0030] In step S103, the opening-degree setting part 5d of the expansion-valve control unit 5 sets, with reference to the first table stored in the storing part 5b, a proper use range from the upper limit to the lower limit of an opening degree of the expansion valve corresponding to the refrigerant used, in accordance with the refrigerant used and the capacity range of the evaporator as the refrigeration capacity set in step S102. Details of the processing are as explained above for the opening-degree setting part 5d.

When the processing of step S103 ends, the routine proceeds to step 5104.

[0031] In step S104, the control part 5e of the expansion-valve control unit 5 controls the opening degree of the expansion valve 3 within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used. Details of the processing are as explained above for the control part 5e. When the processing of step 5104 ends, the routine temporarily ends.

[0032] During normal operation of the refrigeration cycle apparatus 100 other than when the refrigeration cycle apparatus 100 is performed for the first time or when the refrigeration cycle apparatus 100 is reset, as in step S104, the control part 5e of the expansion-valve control unit 5 controls the opening degree of the expansion valve 3 within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used, the proper use range being set in advance as a result of previous execution of the routine and stored in the storing pad 5b.

[0033] <Applications> The refrigeration cycle apparatus 100 includes a pressure sensor and a temperature sensor arranged in an area between the outlet of the evaporator and the compressor 1. The pressure sensor may be replaced with a temperature sensor at the inlet of the evaporator. In the case where a situation in which the value of the degree of superheat of refrigerant at the outlet of the evaporator is outside a predetermined range occurs continuously, the control part 5e of the expansion-valve control unit 5 may correct the range of the opening degree of the expansion valve. Specifically, in the case where the value of the degree of superheat of refrigerant at the outlet of the evaporator exceeds the predetermined range, the control pad 5e of the expansion-valve control unit 5 increases the value of the minimum opening degree to 1.05 times the original value. Furthermore, in the case where the value of the degree of superheat of refrigerant at the outlet of the evaporator is smaller than the predetermined range, the control part 5e of the expansion-valve control unit 5 decreases the value of the maximum opening degree to 0.95 times the original value. The control part 5e of the expansion-valve control unit 5 repeatedly performs the above adjustment until the value of the degree of superheat of refrigerant at the outlet of the evaporator falls within the predetermined range.

[0034] <Effects of Embodiment 1> According to Embodiment 1, the refrigeration cycle apparatus 100 includes the refrigerant circuit in which the compressor 1, the condenser 2, the expansion valve 3, and the evaporator 4 are connected in order by a refrigerant pipe. The refrigeration cycle apparatus 100 includes the expansion-valve control unit 5 configured to adjust the opening degree of the expansion valve 3. The expansion-valve control unit 5 is configured to store the first table defining the relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and the opening degree of the expansion valve and set, with reference to the first table, a proper use range from an upper limit to a lower limit of the opening degree of the expansion valve corresponding to a refrigerant that is used. [0035] With this configuration, the first table defines the relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and an opening degree of the expansion valve. By checking a refrigerant that is used and a refrigeration capacity against the first table, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used can be set. Accordingly, even in the case where an abnormality occurs in detection by the temperature sensor at the outlet of the evaporator or in other cases, an opening degree of the expansion valve that is outside the proper use range of the capacity of the evaporator 4 is not output. Thus, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the type of the refrigerant used and the refrigeration capacity of the evaporator 4 for which the expansion valve 3 is used can be set. Consequently, a liquid return operation and a superheat operation can be prevented, and the compressor 1 can thus be prevented from breaking down. [0036] According to Embodiment 1, the expansion-valve control unit 5 is configured to store the second table defining a relationship between a purpose, horsepower, and the capacity range of the evaporator and set, with reference to the second table, the capacity range of the evaporator corresponding to a purpose and horsepower that are input.

[0037] With this configuration, the second table defines the relationship between the purpose, the horsepower, and the capacity range of the evaporator. By checking the purpose and the horsepower input by a setting person against the second table, a capacity range of the evaporator corresponding to the purpose and the horsepower used can be set. Thus, even if the setting person does not know a refrigeration capacity representing the capacity range of the evaporator as a numerical value, the setting person is able to set a capacity range of the evaporator in accordance with the purpose and the horsepower used.

[0038] According to Embodiment 1, the expansion-valve control unit 5 is configured to control the opening degree of the expansion valve 3 within the set proper use range of the opening degree of the expansion valve.

[0039] With this configuration, the opening degree of the expansion valve 3 is controlled to be within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve set by the expansion-valve control unit 5. Thus, the opening degree of the expansion valve is not controlled to be outside the proper use range from the upper limit to the lower limit. Therefore, even in the case where an abnormality occurs in detection by the temperature sensor at the outlet of the evaporator or in other cases, an opening degree of the expansion valve that is outside the proper use range of the capacity of the evaporator 4 is not output. Consequently, a liquid return operation and a superheat operation can be prevented, and the compressor 1 can thus be prevented from breaking down.

[0040] According to Embodiment 1, the expansion-valve control unit 5 includes the processing circuit including the input part 5a configured to receive use information that is input, the storing pad 5b configured to store the first table, the opening-degree setting part 5d configured to set the proper use range of the opening degree of the expansion valve by checking the use information input to the input part 5a against the first table, and the control part 5e configured to control the opening degree of the expansion valve 3 within the set proper use range of the opening degree of the expansion valve. [0041] With this configuration, the first table defines the relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and an opening degree of the expansion valve.

By checking a refrigerant that is used and a refrigeration capacity as use information against the first table, a proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used can be set. The opening degree of the expansion valve 3 is controlled to be within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve set by the expansion-valve control unit 5. Thus, the opening degree of the expansion valve is not controlled to be outside the proper use range from the upper limit to the lower limit. Consequently, even in the case where an abnormality occurs in detection by the temperature sensor at the outlet of the evaporator or in other cases, an opening degree of the expansion valve that is outside the proper use range of the capacity of the evaporator 4 is not output. As described above, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the type of the refrigerant used and the refrigeration capacity of the evaporator 4 for which the expansion valve 3 is used can be set. Thus, a liquid return operation and a superheat operation can be prevented, and the compressor 1 can thus be prevented from breaking down.

[0042] According to Embodiment 1, the storing part 5b is configured to store the second table. The expansion-valve control unit 5 includes, in the processing circuit, the range setting part Sc configured to set the capacity range of the evaporator by checking the use information input to the input part 5a against the second table.

[0043] With this configuration, the second table defines the relationship between a purpose, horsepower, and a capacity range of the evaporator. By checking the purpose and the horsepower input as use information by a setting person against the second table, the capacity range of the evaporator corresponding to the purpose and the horsepower used can be set. Thus, even if the setting person does not know the refrigeration capacity representing the capacity range of the evaporator as a numerical value, the setting person is able to set the capacity range of the evaporator in accordance with the purpose and the horsepower used.

[0044] According to Embodiment 1, the use information is a purpose, horsepower, and a refrigerant that are used for the refrigeration cycle apparatus 100.

[0045] With this configuration, only by a setting person inputting a purpose, horsepower, and a refrigerant that are used as use information, a proper use range from the upper limit to the lower limit of an opening degree of the expansion valve corresponding to the purpose, the horsepower, and the refrigerant used can be set. Accordingly, even in the case where an abnormality occurs in detection by the temperature sensor at the outlet of the evaporator or in other cases, an opening degree of the expansion valve that is outside the proper use range of the capacity of the evaporator 4 is not output. Thus, a liquid return operation and a superheat operation can be prevented, and the compressor 1 can thus be prevented from breaking down.

[0046] According to Embodiment 1, the expansion-valve control unit 5 includes a processing circuit including the input part 5a configured to receive a purpose, horsepower, and a refrigerant that are used and input, the storing part 5b configured to store the first table defining the relationship between the refrigeration capacity representing the capacity range of the evaporator as a numerical value, the plurality of types of refrigerants, and the opening degree of the expansion valve and a second table that defines a relationship between a purpose, horsepower, and the capacity range of the evaporator, the range setting part Sc configured to set, by checking the purpose and the horsepower input to the input part 5a against the second table, the capacity range of the evaporator corresponding to the input purpose and the input horsepower, the opening-degree setting part 5d configured to set, by checking the capacity range of the evaporator set by the range setting part Sc and the refrigerant input to the input part 5a against the first table, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used, and the control part be configured to control the opening degree of the expansion valve 3 within the set proper use range of the opening degree of the expansion valve.

[0047] With this configuration, the second table defines the relationship between a purpose, horsepower, and a capacity range of the evaporator By checking the purpose and the horsepower input by a setting person against the second table, the capacity range of the evaporator corresponding to the purpose and the horsepower used can be set. Furthermore, the first table defines the relationship between a refrigeration capacity representing a capacity range of the evaporator as a numerical value, a plurality of types of refrigerants, and an opening degree of the expansion valve. By checking a refrigerant that is used and a refrigeration capacity against the first table, a proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used can be set. The opening degree of the expansion valve 3 is controlled to be within the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve set by the expansion-valve control unit 5. Accordingly, the opening degree of the expansion valve is not controlled to be outside the proper use range from the upper limit to the lower limit. Thus, even in the case where an abnormality occurs in detection by the temperature sensor at the outlet of the evaporator or in other cases, an opening degree of the expansion valve that is outside the proper use range of the capacity of the evaporator 4 is not output. As described above, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the type of the refrigerant used and the refrigeration capacity of the evaporator 4 for which the expansion valve 3 is used can be set. Thus, a liquid return operation and a superheat operation can be prevented, and the compressor 1 can thus be prevented from breaking down.

[0048] According to Embodiment 1, the expansion valve 3 is an electronic expansion valve that is integrated with the expansion-valve control unit 5.

[0049] With this configuration, the expansion valve 3 is an electronic expansion valve that is integrated with the expansion-valve control unit 5. Thus, the refrigeration cycle apparatus 100 does not include any unnecessary component, and an increase in the number of components is prevented. The expansion valve 3 and the expansion-valve control unit 5 are not necessarily integrated with each other.

Reference Signs List [0050] 1 compressor 2 condenser 3 expansion valve 4 evaporator 5 expansion-valve control unit 5a input part 5b storing part 5c range setting part 5d opening-degree setting part 5e control part 6 communication line 100 refrigeration cycle apparatus

Claims

CLAIMS[Claim 1] A refrigeration cycle apparatus, comprising: a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order by a refrigerant pipe; and an expansion-valve control unit configured to adjust an opening degree of the expansion valve, in a state in which a first table that defines a relationship between a refrigeration capacity, a plurality of types of refrigerants, and the opening degree of the expansion valve is stored in the expansion-valve control unit and a second table that defines a relationship between a purpose, horsepower, and a capacity range of the evaporator is stored in the expansion-valve control unit, the expansion-valve control unit being configured to set, with reference to the second table, the capacity range of the evaporator corresponding to a purpose and horsepower that are input and set a proper use range from an upper limit to a lower limit of the opening degree of the expansion valve corresponding to a refrigerant that is used by checking the set capacity range of the evaporator and a refrigerant that is input against the first table.[Claim 2] The refrigeration cycle apparatus of claim 1, wherein the expansion-valve control unit is configured to control the opening degree of the expansion valve within the set proper use range of the opening degree of the expansion valve.[Claim 3] The refrigeration cycle apparatus of claim 1 or 2, wherein the expansion-valve control unit includes a processing circuit including an input part configured to receive use information that is input, a storing part configured to store the first table, an opening-degree setting part configured to set the proper use range of the opening degree of the expansion valve by checking the use information input to the input part against the first table, and a control part configured to control the opening degree of the expansion valve within the set proper use range of the opening degree of the expansion valve.[Claim 4] The refrigeration cycle apparatus of claim 3, wherein the storing pad is configured to store the second table, and the expansion-valve control unit includes, in the processing circuit, a range setting part configured to set the capacity range of the evaporator by checking the use information input to the input part against the second table.[Claim 5] The refrigeration cycle apparatus of claim 3 or 4, wherein the use information is a purpose, horsepower, and a refrigerant that are used for the refrigeration cycle apparatus.[Claim 6] The refrigeration cycle apparatus of claim 1, wherein the expansion-valve control unit includes a processing circuit including an input part configured to receive a purpose, horsepower, and a refrigerant that are used and input, a storing part configured to store a first table that defines the relationship between the refrigeration capacity representing the capacity range of the evaporator as a numerical value, the plurality of types of refrigerants, and the opening degree of the expansion valve and the second table defining the relationship between a purpose, horsepower, and the capacity range of the evaporator, a range setting part configured to set, by checking the purpose and the horsepower input to the input part against the second table, the capacity range of the evaporator corresponding to the input purpose and the input horsepower, an opening-degree setting part configured to set, by checking the capacity range of the evaporator set by the range setting part and the refrigerant input to the input part against the first table, the proper use range from the upper limit to the lower limit of the opening degree of the expansion valve corresponding to the refrigerant used, and a control pad configured to control the opening degree of the expansion valve within the set proper use range of the opening degree of the expansion valve. [Claim 7] The refrigeration cycle apparatus of any one of claims 1 to 6, wherein the expansion valve is an electronic expansion valve integrated with the expansion-valve control unit.