The present invention relates to a refrigeration cycle apparatus, and particularly to a refrigeration cycle apparatus having a function of detecting a leakage of refrigerant.
In a refrigeration cycle apparatus, air conditioning is performed by heat exchange accompanied with liquefaction (condensation) and vaporization (evaporation) of circulating refrigerant that is sealed therein. Japanese Patent Laying-Open No. 2002-228281 (PTL 1) discloses that, when a leakage of refrigerant is detected in a room in which an indoor unit is installed, a compressor and an outdoor blower fan are operated in the state where an on-off valve for interrupting the flow of liquid refrigerant is closed, thereby recovering the refrigerant in a receiver tank and a heat exchanger in an outdoor unit.
The similar refrigerant recovery operation (a pump down operation) is disclosed also in Japanese Patent Laying-Open No. 2016-11783 (PTL 2), Japanese Patent Laying-Open No. 2013-122364 (PTL 3), and Japanese Patent Laying-Open No. 2004-286315 (PTL 4).
According to the disclosure in PTL 1, during recovery of refrigerant, when a pressure detector disposed downstream of an on-off valve located downstream of a receiver tank detects a prescribed pressure in a cooling operation, the compressor is stopped to end the pump down operation.
However, PTL 1 to PTL 4 each disclose the termination condition for the pump down operation but do not particularly disclose abnormality detection performed until the termination condition is satisfied by a pressure decrease or the like resulting from recovery of refrigerant.
Accordingly, when a certain abnormality, for example, a failure or the like in a compressor, an outdoor blower fan, a pressure detector, or an on-off valve occurs during a pump down operation, the recovery of refrigerant is not normally completed. Thus, the pump down operation may be continuously performed while the termination condition remains unsatisfied. Such a situation may cause a concern that a user cannot be appropriately notified about an abnormality.
The present disclosure has been made to solve the above-described problems. An object of the present disclosure is to provide appropriate user guidance in a refrigerant recovery operation started upon detection of a leakage of refrigerant in a refrigeration cycle apparatus including a refrigerant leakage sensor.
In an aspect of the present disclosure, a refrigeration cycle apparatus equipped with an outdoor unit and at least one indoor unit includes: a compressor; an outdoor heat exchanger provided in the outdoor unit; an indoor heat exchanger provided in the indoor unit; a refrigerant pipe; a first interruption mechanism; a leakage sensor for refrigerant; and an information output unit configured to output information to a user. The refrigerant pipe is configured to connect the compressor, the outdoor heat exchanger, and the indoor heat exchanger. The first interruption mechanism is provided in a path that connects the outdoor heat exchanger and the indoor heat exchanger without passing through the compressor in a refrigerant circulation path that has the compressor, the outdoor heat exchanger, the indoor heat exchanger, and the refrigerant pipe. The leakage sensor is configured to detect a leakage of refrigerant that flows through the refrigerant pipe. When the leakage sensor detects a leakage of the refrigerant, a refrigerant recovery operation is performed until a termination condition based on a predetermined state amount is satisfied. In the refrigerant recovery operation, the first interruption mechanism interrupts a flow of the refrigerant and the compressor is operated in a state where the refrigerant circulation path is formed in a direction in which the refrigerant discharged from the compressor passes through the outdoor heat exchanger and subsequently passes through the indoor heat exchanger. When an abnormality in the refrigerant recovery operation is detected during the refrigerant recovery operation, the information output unit outputs guidance information for notifying the user about the abnormality.
According to the present disclosure, appropriate user guidance can be provided in a refrigerant recovery operation started upon detection of a leakage of refrigerant in a refrigeration cycle apparatus including a refrigerant leakage sensor.
The embodiments of the present invention will be hereinafter described in detail with reference to the accompanying drawings. In the following description, the same or corresponding components in the accompanying drawings will be designated by the same reference characters, and description thereof will not be basically repeated.
Referring to
Outdoor unit 20 includes an outdoor unit controller 30. Indoor units 40a and 40b include indoor unit controllers 50a and 50b, respectively. Each of outdoor unit controller 30 and indoor unit controllers 50a and 50b can be formed of a microcomputer including a central processing unit (CPU), memory such as a random access memory (RAM) and a read only memory (ROM), and an input/output interface, and the like, each of which is not shown.
Air conditioning system 100 further includes an air conditioning system controller 10. Air conditioning system controller 10 can be formed of a remote controller into which a user command can be input. Examples of the user command may include commands to start and stop an operation, a command to set a timer operation, a command to select an operation mode, a command to set a temperature, and the like.
For example, air conditioning system controller 10 can be disposed in target space 60 or an operation management room in which a maintenance manager stays for centralized control of the plurality of target spaces 60. Air conditioning system controller 10 can be configured such that a user (for example, including a maintenance manager and a serviceman) can input, thereinto, not only the command to operate outdoor unit 20 or indoor units 40a and 40b but also the command to operate the entire refrigeration cycle apparatus.
The microcomputer (not shown) stored in air conditioning system controller 10 is configured to be capable of bidirectionally transmitting and receiving data to and from outdoor unit controller 30, indoor unit controllers 50a and 50b. Furthermore, air conditioning system controller 10 includes an information output unit 15 configured to output a message in at least one of a visual manner and an auditory manner for notifying a user about information. Information output unit 15 is configured, for example, to include at least one of a display screen such as a liquid crystal panel and a speaker. The operation of information output unit 15 is controlled by the microcomputer of air conditioning system controller 10. For example, information output unit 15 is provided on the surface or on the outside of the remote controller.
Furthermore, an information output unit 35 similar to information output unit 15 can be disposed so as to correspond to outdoor unit 20. Similarly, information output units 45a and 45b can be disposed so as to correspond to indoor units 40a and 40b, respectively. The operation of information output unit 35 can be controlled by outdoor unit controller 30. The operation of information output unit 45 (45a, 45b) can be controlled by indoor unit controllers 50a and 50b. In the following, these information output units will also be simply collectively referred to as an information output unit 105. Specifically, in the refrigeration cycle apparatus according to the present embodiment, at least one information output unit 105 is disposed so as to correspond to at least any one of air conditioning system controller 10, outdoor unit controller 30, and indoor unit controllers 50a and 50b.
Furthermore, the function of controlling each component of the refrigeration cycle apparatus according to the present embodiment is shared among air conditioning system controller 10, outdoor unit controller 30, and indoor unit controllers 50a and 50b. In the following, air conditioning system controller 10, outdoor unit controller 30, and indoor unit controllers 50a and 50b will be simply collectively referred to as a controller 101.
A refrigerant leakage sensor 70 is disposed in target space 60 for air conditioning. Refrigerant leakage sensor 70 detects the refrigerant gas concentration in atmosphere for the refrigerant used in the refrigeration cycle apparatus, for example. Representatively, refrigerant leakage sensor 70 can be configured to output a detection signal when the refrigerant gas concentration increases above a predetermined reference value. Alternatively, for detecting a decrease in the oxygen concentration caused by an increase in the refrigerant gas concentration, refrigerant leakage sensor 70 may be configured to output a detection signal when the oxygen concentration decreases below a reference value. The output from refrigerant leakage sensor 70 is transmitted to indoor unit controllers 50a and 50b, outdoor unit controller 30, and air conditioning system controller 10.
In the following explanation, indoor units 40a and 40b and elements thereof are denoted by reference numerals with no suffix when the description is common to the units; whereas indoor units 40a and 40b and elements thereof are denoted by reference numerals with suffixes a and b when the units are distinguished from each other. For example, each of indoor unit controllers 50a and 50b is also denoted simply as an indoor unit controller 50 in the description of the feature common to indoor unit controllers 50a and 50b.
In the configuration example in
Referring to
Compressor 201 is configured to be capable of changing an operation frequency by the control signal from outdoor unit controller 30. By changing the operation frequency of compressor 201, the output from the compressor is adjusted. Compressor 201 may be of various types, for example, such as a rotary type, a reciprocating type, a scroll type, and a screw type as appropriate. Four-way valve 202 has ports E, F, G, and H. Outdoor heat exchanger 203 has ports P3 and P4.
The refrigeration cycle apparatus includes indoor unit 40 (40a, 40b) provided with: an indoor heat exchanger 207 (207a, 207b); an indoor fan 208 (208a, 208b); and an indoor expansion valve 209 (209a, 209b). Pipe 231, indoor heat exchanger 207a, indoor expansion valve 209a, and pipe 232 are connected in this order while pipe 231, indoor heat exchanger 207b, indoor expansion valve 209b, and pipe 232 are connected in this order. Indoor heat exchanger 207a and indoor expansion valve 209a are connected in parallel with indoor heat exchanger 207b and indoor expansion valve 209b. Indoor heat exchanger 207a has ports P1a and P2a. Indoor heat exchanger 207b has ports P1b and P2b.
Each of outdoor expansion valve 206 and indoor expansion valves 209a and 209b can be formed of an electronic expansion valve (LEV) having a degree of opening that is electronically controlled. In indoor unit 40, according to the control signal from indoor unit controller 50 (50a, 50b), the degree of opening of indoor expansion valve 209 (209a, 209b) is controlled to be: fully opened; SH (superheat: degree of superheat)-controlled; SC (subcool: degree of supercooling)-controlled; or closed (fully closed). Similarly, the degree of opening of outdoor expansion valve 206 is controlled by outdoor unit controller 30, for example, so as to include degrees to be fully opened and fully closed.
In indoor unit 40, indoor unit controller 50 (50a, 50b) controls: the operation of indoor fan 208 (208a, 208b) to be stopped and started; and the rotation speed of indoor fan 208 (208a, 208b) during the operation. Furthermore, in outdoor unit 20, outdoor unit controller 30 controls: the operation of compressor 201 to be stopped and started; the frequency of compressor 201 during the operation; the operation of outdoor fan 205 to be stopped and started; the rotation speed of outdoor fan 205 during the operation; the state of four-way valve 202; and on-off valve 211 to be opened or closed.
In outdoor unit 20, pipe 220 connects port H of four-way valve 202 and a gas-side refrigerant pipe connection hole 21 of outdoor unit 20. Pipe 220 is provided with on-off valve 211. On the outside of outdoor unit 20, one end of refrigerant pipe 80x is connected to gas-side refrigerant pipe connection hole 21. The other end of refrigerant pipe 80x is connected through pipe 231 on the indoor unit 40 side to port P1a on one side of indoor heat exchanger 207a and port P1a on one side of indoor heat exchanger 207b.
On the inside of indoor unit 40, indoor heat exchanger 207 and indoor expansion valve 209 are connected in series between pipes 231 and 232. In the configuration example in
In outdoor unit 20, pipe 221 connects liquid-side refrigerant pipe connection hole 22 of the outdoor unit and port P4 of outdoor heat exchanger 203. Pipe 221 is provided with high-pressure receiver 204 and outdoor expansion valve 206. High-pressure receiver 204 is connected between port P4 and outdoor expansion valve 206.
Pipe 222 connects port P3 of outdoor heat exchanger 203 and port F of four-way valve 202. Pipe 223 connects port E of four-way valve 202 and a suction side 201b of compressor 201. Pipe 224 connects a discharge side 201a of compressor 201 and port G of four-way valve 202. In this way, refrigerant pipe 80 (80x, 80y) and pipes 220 to 225, 231, and 232 can constitute a “refrigerant pipe” through which compressor 201, outdoor heat exchanger 203, and indoor heat exchanger 207 are connected in a circulation manner.
On pipe 223, a pressure sensor 210 for detecting the pressure on the suction side (the low-pressure side) of compressor 201 is disposed. A detection value Pl by pressure sensor 210 (hereinafter also referred to as a low-pressure detection value Pl) is input into outdoor unit controller 30.
Outdoor unit 20 is provided with a temperature sensor 214 for detecting an atmospheric temperature. Similarly, indoor units 40a and 40b are provided with temperature sensors 215a and 215b, respectively, for sensing the atmospheric temperature. A detection temperature Tot by temperature sensor 214 is input into outdoor unit controller 30. Detection temperatures Tra and Trb by temperature sensors 215a and 215b are input into indoor unit controllers 50a and 50b, respectively.
Then, a refrigerant circulation path in the refrigeration cycle apparatus will be described.
Four-way valve 202 is controlled by the signal from outdoor unit controller 30 to bring about the first state (cooling operation state: state 1) and the second state (heating operation state: state 2). In the first state, port G is in communication with port F while port E is in communication with port H. In the second state, port G is in communication with port H while port E is in communication with port F. In other words, port E corresponds to the “first port”, port F corresponds to the “second port”, port G corresponds to the “third port”, and port H corresponds to the “fourth port”.
When compressor 201 is operated while four-way valve 202 is in state 1 (cooling operation state), the refrigerant circulation path is formed in the direction indicated by solid line arrows in
In indoor unit 40, the refrigerant is evaporated (vaporized) as a result of heat absorption in indoor heat exchanger 207 when the refrigerant flows through pipe 232 and indoor expansion valve 209 and then passes through indoor heat exchanger 207. The vaporized refrigerant flows through pipe 231, refrigerant pipe 80x and pipes 220 and 223 so as to be returned to suction side 201b of compressor 201. Thereby, target space 60 (
In other words, in the cooling operation state, a refrigerant circulation path is formed in the direction in which the refrigerant discharged from compressor 201 passes through outdoor heat exchanger 203 and subsequently passes through indoor heat exchanger 207.
On the other hand, in state 2 (heating operation state), the refrigerant circulation path is formed in the direction indicated by dotted line arrows in
In outdoor unit 20, the refrigerant is evaporated (vaporized) as a result of heat absorption in outdoor heat exchanger 203 when the refrigerant flows through pipe 221, outdoor expansion valve 206 and high-pressure receiver 204 and then passes through outdoor heat exchanger 203. The vaporized refrigerant flows through pipes 222 and 223 so as to be returned to suction side 201b of compressor 201. Thereby, target space 60 (
In each of state 1 (cooling operation state) and state 2 (heating operation state), outdoor expansion valve 206 is provided in a path that connects outdoor heat exchanger 203 and indoor heat exchanger 207 without passing through compressor 201 in the refrigerant circulation path including compressor 201, outdoor heat exchanger 203, indoor heat exchanger 207, and refrigerant pipes 80x and 80y. Thus, outdoor unit controller 30 controls outdoor expansion valve 206 to be fully closed, so that the “first interruption mechanism” can be formed. Alternatively, a valve (representatively, an on-off valve) for forming the “first interruption mechanism” can also be disposed on pipe 221 or refrigerant pipe 80y. In this way, the “first interruption mechanism” has a function of interrupting the flow of the refrigerant in a liquid state on the refrigerant circulation path.
The following is an explanation about control performed upon detection of a leakage of refrigerant by refrigerant leakage sensor 70 in the refrigeration cycle apparatus according to the first embodiment.
Referring to
Based on the output from refrigerant leakage sensor 70, controller 101 monitors whether refrigerant leaks or not in target space 60 during the operation of the air conditioning system. When refrigerant leakage sensor 70 does not output a detection signal about a leakage of refrigerant, it is determined as NO in step S120. Then, the air conditioning operation according to an operation command is continued.
When refrigerant leakage sensor 70 outputs a detection signal, it is determined as YES in step S120, and controller 101 starts the process subsequent to step S130.
In step S130, using information output unit 105, controller 101 notifies the user that a leakage of refrigerant occurs in target space 60 in which refrigerant leakage sensor 70 is disposed. In this case, it is preferable that information output unit 105 that outputs a message in at least one of a visual manner and an auditory manner includes information output units 45 in indoor units 40a and 40b.
Furthermore, in step S140, the controller determines whether the refrigeration cycle apparatus is performing the heating operation or not. When the refrigeration cycle apparatus is performing the heating operation (determined as YES in S140), the controller switches four-way valve 202 to bring about state 1 (the cooling operation state) in step S150. On the other hand, when the refrigeration cycle apparatus is performing the cooling operation (determined as NO in step S140), four-way valve 202 is maintained in state 1 (the cooling operation state). Thereby, when a leakage of refrigerant is detected, a refrigerant circulation path in the cooling operation is formed, that is, a refrigerant circulation path is formed in the direction in which the refrigerant discharged from compressor 201 passes through outdoor heat exchanger 203 and subsequently passes through indoor heat exchanger 207.
In the state where the refrigerant circulation path in the cooling operation is formed, controller 101 controls outdoor expansion valve 206 to be fully closed in step S160. When compressor 201 is continuously operated in the state where outdoor expansion valve 206 interrupts the path through which the refrigerant in a liquid state is delivered to indoor unit 40, the refrigerant recovery operation by the so-called pump down operation is performed. In step S170, controller 101 controls indoor expansion valve 209 to be fully opened in the refrigerant recovery operation.
Again referring to
In the refrigerant recovery operation, the amount of refrigerant in a liquid state to be recovered in outdoor unit 20 can be increased by disposing high-pressure receiver 204. In other words, high-pressure receiver 204 corresponds to one example of an “accumulation mechanism”. In addition, without providing high-pressure receiver 204 in the configuration in
In the refrigerant recovery operation, it is preferable to promote evaporation (vaporization) in indoor heat exchanger 207 in order to increase the amount of refrigerant to be recovered. Thus, it is preferable that indoor expansion valves 209a and 209b are fully opened in step S170 while indoor fans 208a and 208b are operated with maximum output.
Again referring to
In the refrigerant recovery operation, as recovery of refrigerant progresses, the pressure on the low-pressure side of compressor 201, that is, low-pressure detection value Pl by pressure sensor 210 in
Referring to
Each of pressure change characteristics fa(t) and fb(t) decreases over time from a pressure value P0 at the start of the refrigerant recovery operation (t=0). However, when an abnormality occurs due to failures or the like in compressor 201, outdoor fan 205, outdoor expansion valve 206, or pressure sensor 210, the change (decrease) in low-pressure detection value Pl is reduced as compared with pressure change characteristic fa(t) in a normal state as shown by pressure change characteristic fb(t).
According to pressure change characteristic fa(t) in a normal state, low-pressure detection value Pl decreases eventually to a final pressure (negative pressure) that is lower than atmospheric pressure. On the other hand, according to pressure change characteristic fb(t) in an abnormal state, low-pressure detection value Pl stops to decrease in a region equal to atmospheric pressure or in a region higher than atmospheric pressure. Thus, when a reference value Ps is set to be greater than the above-mentioned final pressure in a normal state, the condition at the point of time of t=ts shows that Pl<Ps in a normal state, whereas Pl>Ps in an abnormal state. Thus, low-pressure detection value Pl does not decrease below reference value Ps.
Accordingly, the termination condition for the refrigerant recovery operation in step S180 in
Furthermore, in a normal state, low-pressure detection value Pl decreases to reference value Ps at the point of time of t=t3. In this case, the time length until t3 or the time length having a margin until t3 is set as a reference time period ts. Thereby, when low-pressure detection value Pl does not decrease to reference value Ps (hereinafter also referred to as “upon occurrence of timeout”) at the point of t=ts (in other words, even when reference time period ts has elapsed), an abnormality in the refrigerant recovery operation can be detected. In other words, reference time period ts corresponds to the “first reference time period” or the “second reference time period”.
Alternatively, as indicated by a broken line in
Thus, by comparing low-pressure detection value Pl with the reference pressure value at each elapsed time, an abnormality in the refrigerant recovery operation can be detected before a lapse of reference time period ts. For example, in the case where Pl>P1 at the point of time of t=t1 or in the case where Pl>P2 at the point of time of t=t2, an abnormality in the refrigerant recovery operation can be detected. In other words, an optional elapsed time (one or more) before a lapse of reference time period ts is set as the “third or predetermined reference time period”. In this case, when low-pressure detection value Pl (that is, the “state amount”) in the third or predetermined reference time period is greater than the reference pressure value (that is, the “reference state amount”), an abnormality in the refrigerant recovery operation can be detected.
In addition, reference change characteristic fr(t) can be defined not by the reference pressure value showing the pressure value itself but by the reference value about the degree of pressure change (degree of decrease) ΔP(t) from the start of the refrigerant recovery operation (which will be hereinafter referred to as the degree of reference pressure decrease). Degree of pressure decrease ΔP(t) at each point of time can be defined by the amount of pressure change (decrease) or the rate of pressure change (decrease) from an initial value P0 of low-pressure detection value Pl.
Reference change characteristic fr(t) corresponds to the collection of the degrees of reference pressure decrease at each elapsed time t from the start of the refrigerant recovery operation. While focusing attention on the fact that the degree of change (degree of decrease) ΔP of the pressure detection value is smaller in an abnormal refrigerant recovery operation than in a normal refrigerant recovery operation, an abnormality in the refrigerant recovery operation can be detected before a lapse of reference time period ts. In other words, also when the degree of pressure decrease ΔP(t) as the amount of decrease or as the rate of decrease of low-pressure detection value Pl with respect to initial value P0 is smaller than the degree of reference pressure decrease, an abnormality in the refrigerant recovery operation can be detected.
Alternatively, the reference change amount of low-pressure detection value Pl per unit time is set. Thereby, when the change amount of low-pressure detection value Pl per unit time is smaller than the reference change amount, an abnormality in the refrigerant recovery operation can also be detected. For example, the reference change amount can be set in accordance with reference change characteristic fr(t).
Again referring to
Specifically, in step S190, controller 101 stops compressor 201 to end the refrigerant recovery operation. Then in step S200, controller 101 closes on-off valve 211. Thereby, the refrigerant (in a liquid state) recovered in outdoor unit 20 can be prevented from flowing back to indoor unit 40. In other words, on-off valve 211 corresponds to one example of the “second interruption mechanism”.
Further in step S210, controller 101 notifies a user about completion (normal termination) of the refrigerant recovery operation and support therefor. Specifically, information output unit 105 outputs a message to a user.
When the termination condition is not satisfied during the refrigerant recovery operation (determined as NO in S180), controller 101 determines in step S220 whether the abnormality detection condition for the refrigerant recovery operation has been satisfied or not. For example, upon occurrence of timeout as described above or upon detection that the degree of change ΔP with time of the pressure detection value as the “state amount” is smaller than the degree of change in accordance with reference change characteristic fr(t), the abnormality detection condition for the refrigerant recovery operation is satisfied, and thereby, it is determinate as YES in S220. In other words, an abnormality in the refrigerant recovery operation can be detected based on the behavior of low-pressure detection value Pl as the “state amount”, which appears until the termination condition is satisfied. On the other hand, the refrigerant recovery operation is continued while it is determined as NO both in steps S180 and S220.
When an abnormality in the refrigerant recovery operation is detected (determined as YES in S220), controller 101 stops compressor 201 to end the refrigerant recovery operation in the above-mentioned S190, and closes on-off valve 211 in the above-mentioned step S200.
When the refrigerant recovery operation is ended as a result of detection of an abnormality, controller 101 causes the process to proceed to step S230, in which indoor expansion valves 209a and 209b are fully closed. Thereby, even when unrecovered refrigerant remains on the side of indoor unit 40, remaining refrigerant can be prevented from leaking out from indoor heat exchanger 207.
In step S240, controller 101 notifies the user about occurrence of an abnormality in the refrigerant recovery operation and support therefor. For example, in step S240, information output unit 105 can output: a message for notifying the user that “refrigerant may not have been appropriately recovered”; and a message for urging the user to “ventilate a room and make contact with a service company”.
In this way, according to the refrigeration cycle apparatus in the first embodiment, when the abnormality detection condition related to the behavior of the low-pressure detection value as the “state amount” is satisfied due to a failure and the like in compressor 201, outdoor fan 205, outdoor expansion valve 206, or pressure sensor 210 during the refrigerant recovery operation automatically started upon detection of a leakage of refrigerant, an abnormality in the refrigerant recovery operation can be detected. Then, upon detection of an abnormality, the refrigerant recovery operation is ended, and information output unit 105 outputs a message about occurrence of an abnormality and support therefor in at least one of a visual manner and an auditory manner. Thereby, appropriate user guidance can be implemented.
As shown in
Referring to
For reference change characteristic fr(t) and reference time period ts of low-pressure detection value Pl, different characteristics and reference values can be set for each combination of the stage of the temperature condition and the stage of the amount of sealed refrigerant.
In the example in
Similarly, when the amount of sealed refrigerant is in a stage M2 (smaller in amount than stage M1), reference change characteristic fr(t) can be set as different characteristics f21(t), f22(t), f23(t), . . . so as to correspond to stages A, B, and C, . . . , respectively, of the temperature condition. Similarly, reference time period ts can be set at different values ts21, ts22, ts23, . . . so as to correspond to stages A, B, C, . . . , respectively, of the temperature condition.
Referring to
A change in low-pressure detection value Pl during the refrigerant recovery operation becomes gentler at a high temperature than at a low temperature. Upon reflection of such a phenomenon, reference time period ts (ts11) at a high temperature (in stage A) is set to be longer than reference time period ts (ts13) at a low temperature (in stage C). Similarly, reference change characteristic fr(t) (fl1(t)) at a high temperature (in stage A) is set to be smaller in degree of change ΔP(t) with time than reference change characteristic fr(t) (fl3(t)) at a low temperature (in stage C).
In other words, depending on the temperature condition, the variable setting can be performed such that, as the temperature is lower, reference time period ts is shorter and reference change characteristic fr(t) is greater in degree of change ΔP(t).
Referring to
A change in low-pressure detection value Pl during the refrigerant recovery operation is gentler in the state of a larger amount of sealed refrigerant than in the state of a smaller amount of sealed refrigerant. Upon reflection of such a phenomenon, reference time period ts (ts11) in the state of a larger amount of sealed refrigerant (in stage M1) is set to be longer than reference time period ts (ts21) in the state of a smaller amount of sealed refrigerant (in stage M2). Similarly, reference change characteristic fr(t) (fl1(t)) in the state of a larger amount of sealed refrigerant (in stage M1) is set to be smaller in degree of pressure change ΔP(t) with time than reference change characteristic fr(t) (fl1(t)) in the state of a smaller amount of sealed refrigerant (in stage M2).
In other words, depending on the amount of sealed refrigerant, the variable setting can be performed such that, as the amount of refrigerant is smaller, reference time period ts is shorter and reference change characteristic fr(t) is larger in degree of change ΔP(t).
In this way, in the refrigerant recovery operation of the refrigeration cycle apparatus according to the first embodiment, the abnormality detection condition can be adjusted in accordance with the temperature condition and the amount of sealed refrigerant, so that erroneous detection of an abnormality can be prevented.
As to the temperature condition, the stage can be selected based on the temperature detection values by temperature sensors 214 and 215 shown in
The modification of the first embodiment will be described below with regard to an example in which the “state amount” used for the termination condition and the abnormality detection condition for the refrigerant recovery operation is set to be different from low-pressure detection value Pl (pressure sensor 210).
When comparing
Based on high-pressure detection value Ph and refrigerant temperature Tq, outdoor unit controller 30 calculates the degree of supercooling (SC) of the accumulated refrigerant (in a liquid state). The degree of supercooling is defined by the value that is obtained by subtracting refrigerant temperature Tq detected by temperature sensor 213 from the value that is obtained by converting high-pressure detection value Ph of pressure sensor 212 into a saturation temperature of the refrigerant.
In the refrigerant recovery operation, as the recovery of refrigerant progresses, the amount of refrigerant (in a liquid state) accumulated in outdoor unit 20 (outdoor heat exchanger 203 and high-pressure receiver 204) increases, so that degree of supercooling SC rises accordingly. Thus, in the modification of the first embodiment, the termination condition and the abnormality detection condition for the refrigerant recovery operation are set assuming that not low-pressure detection value Pl of compressor 201 but the degree of supercooling (SC) on the output side of outdoor heat exchanger 203 is defined as the “state amount”.
Referring to
Therefore, the termination condition for the refrigerant recovery operation in step S180 in
Also, in a normal state, degree of supercooling SC rises to reference value SCs at the point of time of t=t3. Thus, the time length until t3 or the time length having a margin until t3 is set as reference time period ts. Thereby, when degree of supercooling SC does not rise to reference value SCs at the point of time of t=ts, an abnormality in the refrigerant recovery operation resulting from occurrence of timeout can be detected.
Alternatively, while focusing attention on the fact that degree of change (degree of increase) ΔSC of degree of supercooling SC from the start of the refrigerant recovery operation becomes smaller in an abnormal state than in a normal state, an abnormality in the refrigerant recovery operation can be detected before a lapse of reference time period ts. Degree of increase ΔSC(t) at each point of time can be defined by the amount of change (increase) or the rate of increase (rise) about degree of supercooling SC from initial value SC0 at the start of the refrigerant recovery operation.
As indicated by a broken line in
In other words, it can be determined that the termination condition for the refrigerant recovery operation in step S180 in
In addition, for the abnormality detection condition on which degree of supercooling SC is defined as the “state amount”, reference time period ts and reference change characteristic fscr(t) can be set variably in accordance with the temperature condition and the amount of sealed refrigerant. Specifically, depending on the temperature condition, the variable setting can be performed such that, as the temperature is lower, reference time period ts is shorter and reference change characteristic fr(t) is larger in degree of change ΔP(t). Furthermore, depending on the amount of sealed refrigerant, the variable setting can be performed such that, as the amount of refrigerant is larger, reference time period ts is shorter and reference change characteristic fr(t) is larger in degree of change ΔP(t).
Furthermore, it is understood that, in the refrigerant recovery operation, the refrigerant gas concentration detected by refrigerant leakage sensor 70 decreases as recovery of the refrigerant progresses. Accordingly, in each of the configurations in
Referring to
Accordingly, in a normal state, refrigerant gas concentration v decreases to reference value vs at the point of time of t=t3. In contrast, in an abnormal state, refrigerant gas concentration v does not decrease to reference value vs. Thus, the termination condition for the refrigerant recovery operation in step S180 in
Furthermore, the time length until t3 during which refrigerant gas concentration v decreases to reference value vs in a normal state or the time length having a margin until t3 is set as reference time period ts. Thereby, when refrigerant gas concentration v does not decrease to reference value vs at the point of time of t=ts, an abnormality in the refrigerant recovery operation resulting from occurrence of timeout can be detected.
Alternatively, while focusing attention on the fact that degree of change (degree of decrease) Δv of refrigerant gas concentration v from the start of the refrigerant recovery operation is smaller in an abnormal state than in a normal state, an abnormality in the refrigerant recovery operation can also be detected before a lapse of reference time period ts. Degree of decrease Δv(t) at each point of time can be defined by the amount of change (decrease) or the rate of increase (decrease) of refrigerant gas concentration v from an initial value v0 at the start of the refrigerant recovery operation.
As indicated by a broken line in
In other words, it can be determined that the termination condition for the refrigerant recovery operation in step S180 in
Also for the abnormality detection condition on which refrigerant gas concentration v is defined as the “state amount”, reference time period ts and reference change characteristic fscr(t) can be set variably in accordance with the temperature condition and the amount of sealed refrigerant. Specifically, depending on the temperature condition, the variable setting can be performed such that, as the temperature is lower, reference time period ts is shorter and reference change characteristic fr(t) is larger in degree of change ΔP(t). Furthermore, depending on the amount of sealed refrigerant, the variable setting can be performed such that, as the amount of refrigerant is smaller, reference time period ts is shorter and reference change characteristic fr(t) is larger in degree of change ΔP(t).
As having been described in the modification of the first embodiment, in the refrigeration cycle apparatus according to the present embodiment, normal termination of the refrigerant recovery operation and occurrence of an abnormality in the refrigerant recovery operation can be detected in the state where the state amount is selected as appropriate.
The second embodiment will be hereinafter described with regard to a modification of the configuration of a refrigerant circuit in a refrigeration cycle apparatus.
When comparing
Furthermore, in the configuration in
Bypass pipe 241 is disposed such that the refrigerant having passed through outdoor heat exchanger 203 is routed, during the cooling operation, to a refrigerant inlet of accumulator 218 from the refrigerant path (pipe 221) through which the refrigerant is delivered to indoor unit 40. An expansion valve 242 is provided at some midpoint in bypass pipe 241. An electronic expansion valve (LEV) having a degree of opening that is electronically controlled according to the command from outdoor unit controller 30 is applicable to expansion valve 242.
Inside heat exchanger 243 is configured to perform heat exchange between the refrigerant flowing through bypass pipe 241 and the refrigerant flowing through pipe 221 in the refrigerant circuit. By opening expansion valve 242 (the degree of opening >0), a bypass path for refrigerant is formed so as to extend through inside heat exchanger 243 to accumulator 218. Furthermore, by changing the degree of opening, the amount of refrigerant that passes through the bypass path can be adjusted. On the other hand, by closing expansion valve 242 (the degree of opening=0: fully closed state), the refrigerant bypass path extending through bypass pipe 241 can be interrupted.
During the operation of the refrigeration cycle apparatus, formation of a refrigerant bypass path by bypass mechanism 240 leads to heat exchange in inside heat exchanger 243, so that liquefaction of the refrigerant that flows through pipe 221 can be promoted. Thereby, refrigerant noise can be suppressed while pressure loss can be suppressed.
In the configuration in
Also in the configuration in which accumulator 218 is disposed, the termination condition and the abnormality detection condition for the refrigerant recovery operation can be set as described in the first embodiment, assuming that low-pressure detection value Pl by pressure sensor 210 disposed in the same manner as in
Alternatively, as having been described in the modification of the first embodiment, the termination condition and the abnormality detection condition for the refrigerant recovery operation can also be set assuming that the refrigerant gas concentration detected by refrigerant leakage sensor 70 is defined as the “state amount” or assuming that degree of supercooling SC calculated from the detection values of pressure sensor 212 and temperature sensor 213 that are disposed in the same manner as in
Furthermore, in the configuration shown in
Alternatively, also in the configuration in
As having been described above in the second embodiment, the termination condition and the abnormality detection condition for the refrigerant recovery operation that is automatically started upon detection of a leakage of the refrigerant in the refrigeration cycle apparatus according to the first embodiment is applicable without limiting the configuration of the refrigerant circuit to the basic configuration shown in
In the third embodiment, a modification of an air conditioning system will be described.
Referring to
Building system controller 130 includes an air conditioning controller 131, a lighting controller 132 and a ventilation controller 133. According to the command to air conditioning system controller 10, air conditioning controller 131 adjusts the air temperature in target space 60 by the cooling function and the heating function performed by the refrigeration cycle apparatus (
According to the instruction from the user, lighting controller 132 controls a lighting device (not shown) disposed in target space 60 to be turned on and off and also controls the intensity of illumination when the lighting device is turned on. According to the instruction from the user, ventilation controller 133 controls the operation of the ventilating device (not shown) disposed in target space 60 to be started and stopped. In addition, each of the functions of air conditioning controller 131, lighting controller 132 and ventilation controller 133 can be implemented as part of the control function implemented by a microcomputer.
Consequently, as part of comprehensive building system control, air conditioning system controller 10 can also control the refrigeration cycle apparatus according to the instruction from air conditioning controller 131. In other words, the refrigerant recovery operation having been described in the first embodiment (including a modification thereof) and the second embodiment can also be performed as part of air conditioning control by building system controller 130. In the configuration example in
In this case, it is preferable that information output unit 105 for a user interface that has been described in the first embodiment (including a modification thereof) and the second embodiment is disposed also in building system controller 130.
Alternatively, building system controller 130 can further include a refrigerant leakage sensing unit 134. Refrigerant leakage sensing unit 134 can receive an output signal from refrigerant leakage sensor 70 through radio communication or through a signal line. In this case, refrigerant leakage sensing unit 134 detects a leakage of refrigerant in target space 60. Detection of a leakage of refrigerant is transmitted from refrigerant leakage sensing unit 134 through air conditioning system controller 10 to outdoor unit controller 30 and indoor unit controller 50. Thereby, the refrigerant recovery operation having been described in the first embodiment (including a modification thereof) and the second embodiment can be performed.
Referring to
Indoor remote controller 110 can be provided with a display unit 115 such as a liquid crystal panel and a speaker (not shown). By display unit 115 and the speaker as described above, information output unit 105 for outputting a message in at least one of a visual manner and an auditory manner to a user can be disposed in indoor remote controller 110. In addition, a plurality of indoor remote controllers 110 may be disposed in the same target space 60.
In the configuration example in
Alternatively, through an electrical connection via a signal line 92 between refrigerant leakage sensor 70 and outdoor unit controller 30, the output signal from refrigerant leakage sensor 70 may be transmitted from outdoor unit controller 30 to indoor unit controller 50 (50a, 50b) and indoor remote controller 110.
In each of the configurations in
Furthermore, in each of the configurations in
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the meaning and scope equivalent to the terms of the claims.
This application is a U.S. national stage application of International Application PCT/JP2017/029048, filed on Aug. 10, 2017, the contents of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/JP2017/029048 | 8/10/2017 | WO | 00 |