JP3800918B2 - Refrigeration equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a refrigeration apparatus, and particularly relates to a noise suppression technique during night operation.
[0002]
[Prior art]
Conventionally, a refrigeration apparatus that performs a vapor compression refrigeration cycle is known, and an air conditioner that performs indoor cooling or the like (see, for example, JP-A-10-132409), or cooling that cools the interior of a refrigerator or freezer It is widely used as an apparatus (for example, see JP-A-11-201569). Specifically, the refrigeration apparatus includes a refrigerant circuit filled with a refrigerant. The refrigerant circuit is provided with a compressor, a condenser, an expansion valve, and an evaporator. In the refrigerant circuit, the refrigerant circulates while undergoing a phase change, and performs a cycle including compression, condensation, expansion, and evaporation processes.
[0003]
And when a refrigerant | coolant evaporates, it absorbs heat from a target object, and this cools a target object. For example, when the refrigeration apparatus is used as a refrigerator or a freezer, the internal air is cooled by the refrigerant absorbing heat from the internal air in the evaporator.
[0004]
[Problems to be solved by the invention]
The refrigeration apparatus includes, for example, a unit including a compressor, a condenser (outdoor heat exchanger), and an outdoor fan that blows air to the condenser (hereinafter referred to as an outdoor unit). Called unit).
[0005]
For example, in a refrigerator, freezer, or showcase for a store where an outdoor unit is installed outside, the compressor and outdoor fan are controlled according to the set temperature in the warehouse, so the air flow rate of the outdoor fan is even at night. Noise sometimes became a problem from night to morning due to an increase in size.
[0006]
On the other hand, for example, a clock function is installed in the operation control means for controlling the operation of the refrigeration apparatus so that the time can be recognized. It can be considered that the outdoor unit is operated silently by suppressing the operation of the compressor and the outdoor fan only during that time period, judging that it is the morning time period. However, in that case, since it is necessary to provide a clock function in the operation control means, the cost becomes high.
[0007]
The present invention was devised in view of such problems, and its object is to reduce nighttime noise generated from the outdoor unit while suppressing an increase in cost in the refrigeration apparatus provided with the outdoor unit. It is to be able to reduce.
[0008]
[Means for Solving the Problems]
In the present invention, silent time control is performed to detect a time zone from night to morning based on a change in outdoor temperature within 24 hours and to suppress driving noise during that time.
[0009]
Specifically, the first solution provided by the present invention is an outdoor unit (11) having a compression mechanism (21), an outdoor heat exchanger (23), and an outdoor fan (15), and detects the outdoor temperature. A refrigeration apparatus including an outdoor temperature sensor (66) and an operation control means (70) for controlling each device is assumed. The operation control means (70) includes a timer (71), and the temperature detected by the outdoor temperature sensor (66) is lower than the predetermined reference temperature within approximately 24 hours starting from the predetermined time. The belt is designed to suppress driving noise.
[0010]
In the first solution means, the operation control means (70) is constituted by a microprocessor, and the timer (71) is constituted so as to be able to detect 24 hours using an oscillation circuit of the microprocessor.
[0011]
Also, In this first solution, The predetermined reference temperature is calculated based on the temperature detected by the outdoor temperature sensor (66). is doing .
[0012]
The present invention also took The second solving means is the first In this solution, the predetermined reference temperature is an average temperature calculated from the temperature detected by the outdoor temperature sensor (66) within 24 hours detected by the timer (71). In this case, the method of calculating the average temperature is arbitrary. For example, the detected temperature every hour can be 24 points of data, and the average value can be calculated.
[0013]
The present invention also took The third solution means the second In the solution, the method of calculating the average value is specified. Specifically, the predetermined reference temperature is detected by the outdoor temperature sensor (66) within the 24 hours detected by the timer (71). The average temperature is calculated from the temperature and the minimum temperature.
[0014]
The present invention also took The fourth solving means is the first In this solution, the predetermined reference temperature is set to a set temperature according to the operating conditions. As the set temperature in this case, a temperature set in advance according to weather data or the season can be used as the reference temperature.
[0015]
The present invention also took The fifth to seventh solving means are the first to fourth. In any one of the solution means, an object to be controlled by the operation control means (70) is specified. 5th In this solution, the outdoor fan (15) is controlled to suppress driving noise, 6th In this solution, the compression mechanism (21) is controlled to suppress the driving noise, 7th In this solution, the outdoor fan (15) and the compression mechanism (21) are controlled to suppress operation noise.
[0016]
The present invention also took The eighth solving means is the sixth or seventh. In this solution, the compression mechanism (21) is configured by a plurality of compressors (22a, 22b) provided in the outdoor unit (11), and the operation control means (70) performs control to suppress operation noise. Sometimes, the compressor (22a, 22b) is configured to reduce the number of operating units.
[0017]
The present invention also took A ninth solving means is the above first to eighth. In any one of the solution means, the operation control means (70) may detect the detected temperature within 24 hours starting from the time of the lowest temperature before the first predetermined time and after the second predetermined time. Is configured to perform control to suppress driving noise during a time period lower than a predetermined reference temperature (for example, average temperature).
[0018]
The present invention also took The tenth solution means the ninth In the above solution, the first predetermined time is set to 3 hours and the second predetermined time is set to 14 hours starting from the time of the lowest temperature.
[0019]
The present invention also took The eleventh solving means is the ninth or tenth. In the solving means, the operation control means (70) sets the detected temperature to a predetermined reference within 24 hours starting from the time of the lowest temperature before the first predetermined time and after the second predetermined time. In the continuous time zone lower than the temperature (for example, the average temperature), the control for suppressing the driving sound is performed.
[0020]
-Action-
In the first solving means, while the timer (71) detects approximately 24 hours starting from a predetermined time, the temperature detected by the outdoor temperature sensor (66) within the approximately 24 hours is less than the predetermined reference temperature. In the lower time zone, the operation control means (70) controls to suppress the operation sound.
[0021]
That is, the time zone in which the detected temperature is lower than the reference temperature in the day is determined to be morning from the night, and silent control is performed only during that time zone. In this case, by using an appropriate reference temperature, it is possible to make the time zone for performing the silent control substantially coincide with the time zone from night to morning.
[0022]
Further, in the first solution means, approximately 24 hours are detected by the timer (71) constituted by the oscillation circuit included in the microprocessor constituting the operation control means (70), and the above control is performed every approximately 24 hours. Is done.
[0023]
Also, This first In this solution, the temperature calculated based on the detected temperature data of the outdoor temperature sensor (66) is used as the predetermined reference temperature, and the above control is performed in a time zone where the detected temperature is lower than that temperature.
[0024]
In particular, the above 2nd and 3rd In the above solution, an average temperature for 24 hours is calculated as the reference temperature. And control which suppresses a driving | running sound is performed in the time slot | zone when detected temperature is lower than average temperature within about 24 hours from the predetermined time. In this case, the time zone where the detected temperature is lower than the average temperature in the day is determined to be morning from the night, and the silent control is performed only during that time zone. Note that, depending on the setting of the starting time, the average temperature obtained from the temperature detected on the previous day is used to perform the silent control on the next day. Therefore, it is possible to largely prevent the time zone where the silent control should be performed on the next day from occurring, and the time zone during which the silent control is performed can be made to substantially coincide with the time zone from night to morning.
[0025]
Also, above 4th In the above solution, silent control is performed when the temperature set in advance according to conditions such as weather data and seasons is set as a reference temperature and the detected temperature is lower than that. Even in this case, by setting an appropriate reference temperature, it is possible to make the time zone for performing the silent control substantially coincide with the time zone from night to morning.
[0026]
Also, above 5th In the solution, the outdoor fan (15) is controlled to suppress the operation noise, 6th In the above solution, the driving sound is suppressed by controlling the compression mechanism (21), 7th In this solution, the outdoor fan (15) and the compression mechanism (21) are controlled to suppress operation noise.
[0027]
In particular, the above 8th In this solution, when a plurality of compressors (22a, 22b) are provided in the outdoor unit (11), the operation is performed by reducing the number of operating compressors (22a, 22b) during silent control.
[0028]
Also, above 9th In this solution, the silent control is performed only in a time zone in which the detected temperature is lower than a reference temperature such as an average temperature and within a range determined with the lowest temperature as a starting point.
[0029]
Specifically, the above 10th As described in the above solution, the detection accuracy is improved by adding to the detection conditions of the time zone in which the silent control is performed before 3 hours and after 14 hours have passed within 24 hours from the time of the lowest temperature. In other words, the temperature of the day varies to some extent depending on the season, but generally the lowest temperature is around dawn (5am to 7am), so if you specify the number of hours for the time of the lowest temperature, A time zone in which the detected temperature is lower than a reference temperature such as an average temperature is determined from night to morning from about 7 pm to 9 pm to about 8 am to 10 am every day.
[0030]
For example, since the dawn is earlier in the summer than in the winter, a time zone in which the detected temperature is lower than the reference temperature is detected between about 7 pm and about 8 am, and the dawn is later in the winter than in the summer. A time period in which the detected temperature is lower than the reference temperature is detected from around the hour until around 10 am. In general, the silence control of the outdoor unit is necessary between about 10pm and 8am. 10th If the two conditions of the above solution (determining a time zone in which the detected temperature is lower than the reference temperature such as the average temperature and further limiting the time zone by the number of hours from the time of the lowest temperature) The time zone in which the silent control is necessary can be obtained almost accurately without being substantially affected by the above.
[0031]
In addition, if the time range specified from the time of the lowest temperature is set appropriately according to the area where the refrigeration system is installed, the time zone from night to morning can be accurately detected according to each area. it can.
[0032]
Also, above 11th In this solution, the time zone for performing the silent control is specified as a continuous time zone within a predetermined time. Therefore, even if a state in which the detected temperature is lower than the reference temperature such as the average temperature does not continue depending on how the temperature changes and the detected temperature suddenly becomes lower than the reference temperature after it has risen, In such a case, since it is difficult to consider that the temperature drops at night, it can be excluded from the target of silent control.
[0033]
【The invention's effect】
Therefore, according to the first solution means, the operation control means (70) does not need to have a clock function, and the timer (71) capable of detecting only the passage of time and the outdoor unit (11) are originally provided. From the outdoor temperature sensor (66), the time zone required for silent control can be determined. And since the silence control can be performed in the time zone calculated | required by these means, it becomes possible to aim at a noise countermeasure, suppressing that cost becomes high.
[0034]
In particular, since the timer (71) is configured using the oscillation circuit originally provided in the microprocessor of the operation control means (70), it is more effective to suppress an increase in cost.
[0035]
Also, above 1st to 4th According to this solution, a time zone where the detected temperature is lower than the reference temperature in the day is determined to be morning from the night, and silent control is performed only during that time zone. And, as the predetermined reference temperature, a calculated value such as an average temperature or a set value according to weather conditions is used, so by using an appropriate reference temperature as necessary, a time zone for performing silent control can be set. It becomes possible to almost coincide with the time zone from night to morning.
[0036]
Also, above 5th to 7th According to this solution, the operation noise is suppressed by controlling the outdoor fan (15) and the compression mechanism (21). In this case, when silent operation is performed by controlling the outdoor fan (15) and the compression mechanism (21), the capacity of the refrigeration device is slightly reduced, but during silent control, because the temperature is reduced at night, It is convenient to suppress a decrease in capacity in a cooling facility such as a store refrigerator or freezer. In other words, during silent control, the compression mechanism (21) and outdoor fan (15) should be controlled in such a range that the decrease in the capacity of the refrigeration system does not become a problem and the operation noise is reduced. That's fine.
[0037]
Also, above 8th According to this solution, since the number of compressors (22a, 22b) operated at night is reduced, the operation noise is reduced. For example, if only two compressors (22a, 22b) are operated during the day but only one is operated at night, the noise caused by the compressors (22a, 22b) can be easily halved.
[0038]
Also, above 9th According to the solution, the silent control is performed by detecting only the time in the time zone in which the detected temperature is lower than the reference temperature such as the average temperature and the range starting from the lowest temperature. In particular, the above 10th In this solution, since the time starting from the time of the lowest temperature is specified before 3 hours have elapsed and after 14 hours have elapsed, the morning can be accurately detected from the night regardless of the season. Therefore, above 9th and 10th According to the solution, it is possible to further improve the accuracy of performing the silent control at night while preventing the deterioration of the ability during the daytime when the ability is required and noise is not a problem.
[0039]
Also, above 11th According to this solution, it is possible to prevent malfunctions such as silent control when the detected temperature is accidentally lower than the reference temperature except at night.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0041]
-Configuration of refrigeration equipment-
As shown in FIG.1 and FIG.2, the freezing apparatus (10) is installed in a convenience store and is for cooling a freezer and a refrigerator simultaneously. The refrigeration apparatus (10) includes one outdoor unit (11), one cascade unit (12), two refrigeration units (13a, 13b), and one refrigeration unit (14).
[0042]
Two refrigeration units (13a, 13b) are connected to the outdoor unit (11) through a high-temperature side liquid side communication pipe (31) and a gas side communication pipe (32). Each refrigeration unit (13a, 13b) is connected in parallel to the outdoor unit (11). The cascade unit (12) is provided in the middle of the liquid side communication pipe (31). A refrigeration unit (14) is connected to the cascade unit (12) through a low temperature side liquid side communication pipe (54) and a gas side communication pipe (55).
[0043]
The high temperature side refrigerant circuit (20) is constituted by the outdoor unit (11), a part of the cascade unit (12), the two refrigeration units (13a, 13b), the liquid side communication pipe (31) and the gas side communication pipe (32). Is configured. On the other hand, the low temperature side refrigerant circuit (50) is constituted by the cascade unit (12), the refrigeration unit (14), the liquid side communication pipe (54) and the gas side communication pipe (55).
[0044]
The high temperature side refrigerant circuit (20) includes a compression mechanism (21), a condenser (23) that is an outdoor heat exchanger, a capillary tube (24), a receiver (25), and a refrigerant heat exchanger (26 ) And two refrigeration evaporators (41a, 41b). Among these, the compression mechanism (21), the condenser (23), the capillary tube (24), and the receiver (25) are provided in the outdoor unit (11). The refrigerant heat exchanger (26) is provided in the cascade unit (12). The refrigeration evaporators (41a, 41b) are provided in the refrigeration units (13a, 13b), respectively.
[0045]
The compression mechanism (21) of the high temperature side refrigerant circuit (20) connects, for example, a first compressor (22a) having a capacity of 5 horsepower and a second compressor (22b) having a capacity of 4 horsepower in parallel. Configured. A check valve (CV) is provided on the discharge side of each compressor (22a, 22b). The discharge side of each compressor (22a, 22b) is connected to the inlet end of the condenser (23). The suction side of each compressor (22a, 22b) is connected to the gas side communication pipe (32). The compression mechanism (21) is configured to have a variable capacity by changing the number of operating compressors (22a, 22b).
[0046]
The discharge side pipe of the compression mechanism (21) is provided with a temperature sensor (68) for detecting the discharge refrigerant temperature and a pressure sensor (65) for detecting the discharge refrigerant pressure. The controller (70), which will be described later, is configured to detect the degree of superheat of the discharged refrigerant based on the discharged refrigerant temperature and the discharged refrigerant pressure detected by the temperature sensor (68) and the pressure sensor (65).
[0047]
The condenser (23) condenses the refrigerant by exchanging heat with outdoor air, and is constituted by, for example, a cross fin type heat exchanger. The outdoor unit (11) is provided with an outdoor fan (15), and outdoor air is sent to the condenser (23) by the outdoor fan (15). The outlet end of the condenser (23) is connected to the receiver (25) via the capillary tube (24). The capillary tube (24) constitutes a decompression mechanism for decompressing the refrigerant sent from the condenser (23) to the receiver (25). An outdoor temperature sensor (66) for detecting the outdoor temperature is provided in the outdoor unit (11).
[0048]
The receiver (25) is formed in a vertically long cylindrical container shape. The lower end of the receiver (25) is connected to the liquid side communication pipe (31) via the refrigerant pipe (33). The refrigerant pipe (33) is provided with a liquid temperature sensor (67) for detecting the temperature of the outlet refrigerant of the receiver (25) and a liquid side solenoid valve (61).
[0049]
The liquid temperature sensor (67) detects the temperature of the liquid refrigerant stored in the receiver (25) by detecting the temperature of the liquid refrigerant flowing out of the receiver (25) and flowing through the refrigerant pipe (33). Is. The liquid side solenoid valve (61) is opened and closed based on the temperature detected by the discharge temperature sensor (68), and constitutes an adjustment opening / closing mechanism for adjusting the flow rate of the liquid refrigerant flowing out from the receiver (25). ing.
[0050]
The receiver (25) is connected to the suction side of the compression mechanism (21) via a decompression pipe (34). Specifically, the decompression pipe (34) has one end connected to the upper end of the receiver (25) and the other end connected to the suction side of the compression mechanism (21). The decompression pipe (34) is provided with a gas side solenoid valve (62). The gas side solenoid valve (62) is opened and closed based on the temperature detected by the liquid temperature sensor (67) in order to maintain the receiver (25) at an intermediate pressure, and constitutes a pressure reducing opening / closing mechanism.
[0051]
The receiver (25) intermittently communicates with the suction side of the compression mechanism (21) through the decompression pipe (34) by opening and closing the gas side solenoid valve (62). For this reason, the gas refrigerant in the receiver (25) is intermittently sucked into the compression mechanism (21), and the internal pressure of the receiver (25) is maintained at a predetermined intermediate pressure. Specifically, the internal pressure of the receiver (25) is set to a predetermined pressure that is lower than the refrigerant condensation pressure in the condenser (23) and higher than the refrigerant evaporation pressure in the refrigeration evaporators (41a, 41b). The receiver (25) is configured to cool the self-evaporated liquid refrigerant flowing into the receiver (25) from the condenser (23) and stored.
[0052]
The refrigerant heat exchanger (26) is a so-called plate heat exchanger formed by stacking a large number of heat transfer plates. One end of the refrigerant heat exchanger (26) is connected to the liquid side communication pipe (31) on the outdoor unit (11) side, and the other end is connected to the liquid side communication pipe (31) on the refrigeration unit (13a, 13b) side. It is connected. In addition, a low temperature side refrigerant circuit (50) is connected to the refrigerant heat exchanger (26). The refrigerant heat exchanger (26) constitutes a cascade condenser in a so-called binary refrigeration system.
[0053]
The high temperature side refrigerant circuit (20) is provided with a bypass pipe (35). The bypass pipe (35) is connected so as to bypass the two refrigeration units (13a, 13b). Specifically, the bypass pipe (35) has one end connected immediately after the refrigerant heat exchanger (26) in the high temperature side refrigerant circuit (20) and the other end connected to the gas side communication pipe (32). The bypass pipe (35) is provided with a bypass solenoid valve (63). When both the refrigeration units (13a, 13b) are thermo-off, the bypass solenoid valve (63) is opened, and the refrigerant circulation in the refrigerant heat exchanger (26) is ensured.
[0054]
The part provided in the refrigeration unit (13a, 13b) in the high temperature side refrigerant circuit (20) constitutes the use side circuit (40a, 40b). Each use side circuit (40a, 40b) has one end connected to the liquid side connecting pipe (31) and the other end connected to the gas side connecting pipe (32). In addition, each use side circuit (40a, 40b) is provided with a use side solenoid valve (64a, 64b) which is a use side opening / closing mechanism together with a refrigeration evaporator (41a, 41b) which is a use side heat exchanger. ing. This use side solenoid valve (64a, 64b) is provided on one end side of the refrigeration evaporator (41a, 41b) in each use side circuit (40a, 40b). That is, in each use side circuit (40a, 40b), a use side solenoid valve (64a, 64b) and a refrigeration evaporator (41a, 41b) are arranged in order from one end to the other end.
[0055]
The refrigeration evaporators (41a, 41b) evaporate the refrigerant by exchanging heat with the air in the refrigerator.For example, similar to the condenser (23), the refrigeration evaporator (41a, 41b) is configured by a cross-fin type heat exchanger. ing. Each refrigeration unit (13a, 13b) is provided with a refrigerator fan (16a, 16b), and the refrigerator air (16a, 16b) causes the refrigerator air (41a, 41b) to pass through the air inside the refrigerator. Will be sent.
[0056]
Thus, in the refrigerant circuit of the present embodiment, instead of providing the expansion mechanism in front of the refrigeration evaporator (41a, 41b), the use side solenoid valve (64a, 64b) is provided, and the use side solenoid valve (64a, 64b) The refrigerant is depressurized by repeating the opening and closing operation of 64b). Each refrigeration unit (13a, 13b) has a first temperature sensor (Th-A1, Th-A2), a second temperature sensor (Th-B1, Th-B2), a suction air temperature sensor (Th-C1), respectively. , Th-C2) and blown air temperature sensors (Th-D1, Th-D2), and based on these detection values, the controller (70) described later opens and closes the use side solenoid valves (64a, 64b). I try to control it.
[0057]
The first temperature sensor (Th-A1, Th-A2) is attached to the heat transfer tube of the refrigeration evaporator (41a, 41b) so as to be located near the inlet end of the heat transfer tube. The first temperature sensors (Th-A1, Th-A2) are for detecting the refrigerant evaporation temperature in the refrigeration evaporators (41a, 41b). The second temperature sensor (Th-B1, Th-B2) is attached to the downstream side of the refrigeration evaporator (41a, 41b) in the use side circuit (40a, 40b). The suction air temperature sensors (Th-C1, Th-C2) are provided in the internal air passage and detect the temperature of the internal air supplied to the refrigeration evaporators (41a, 41b). The blown air temperature sensors (Th-D1, Th-D2) are provided in the internal air passage and detect the internal air temperature after passing through the refrigeration evaporators (41a, 41b). A thermistor is used as each temperature sensor.
[0058]
It should be noted that the decompression of the refrigerant by opening and closing the use side solenoid valves (64a, 64b) in this way is based on the idea of the inventors of the applicant of the present application, An application has already been filed (see Japanese Patent Application No. 2000-033415). In this embodiment, a specific description of control is omitted.
[0059]
On the other hand, in the low temperature side refrigerant circuit (50), a compressor (51), a refrigerant heat exchanger (26), an expansion valve (52), and a refrigeration evaporator (53) are connected. Among these, the compressor (51), the refrigerant heat exchanger (26), and the expansion valve (52) are provided in the cascade unit (12). The refrigeration evaporator (53) is provided in the refrigeration unit (14).
[0060]
In the low temperature side refrigerant circuit (50), the discharge side of the compressor (51) is connected to one end of the refrigerant heat exchanger (26). The other end of the refrigerant heat exchanger (26) is connected to the expansion valve (52). The expansion valve (52) is connected to the inlet end of the refrigeration evaporator (53) via the liquid side communication pipe (54). The outlet end of the refrigeration evaporator (53) is connected to the suction side of the compressor (51) via the gas side communication pipe (55).
[0061]
The refrigeration evaporator (53) is composed of, for example, a cross-fin type heat exchanger, similarly to the condenser (23). This freezing evaporator (53) evaporates the refrigerant by heat exchange with the air in the freezer. The refrigeration unit (14) is provided with a freezer fan (17), and the freezer fan (17) sends the air in the freezer to the freezing evaporator (53).
[0062]
The refrigeration apparatus (10) is provided with a controller (70). As described above, the controller (70) opens and closes the use-side solenoid valves (64a, 64b) of the use-side circuits (40a, 40b), so that the use-side solenoid valves ( 64a, 64b) constitute refrigerant expansion means in the high temperature side refrigerant circuit (20).
[0063]
The controller (70) is constituted by a microprocessor and is configured as operation control means for controlling each device. The controller (70) includes a timer (71) configured to detect 24 hours using an oscillation circuit originally provided in the microprocessor. The average temperature (reference temperature) is calculated every 24 hours from the maximum temperature and the minimum temperature detected by the outdoor temperature sensor (66) within 24 hours detected by the timer (71), while the time of the minimum temperature is calculated. The outdoor fan (15) and the compression mechanism (21) in the time zone where the detected temperature is lower than the average temperature within approximately 24 hours starting from (the time of approximately 24 hours is because the time of the lowest temperature fluctuates every day). ) Or one of them is controlled to suppress driving noise.
[0064]
When the two compressors (22a, 22b) provided in the outdoor unit (11) are operated together, and the controller (70) performs silent control for suppressing operation noise, the controller (70a) , 22b) can be reduced.
[0065]
Further, the controller (70) starts from the time of the lowest temperature within 24 hours set by the timer, before the elapse of 3 hours as the first predetermined time and after the elapse of 14 hours as the second predetermined time. Control is performed to suppress driving noise during a time zone in which the detected temperature is lower than the average temperature.
[0066]
-Refrigerating cycle operation of refrigerant circuit-
The operation of the refrigeration apparatus (10) will be described. First, the operation of the freezing / refrigeration operation for operating both the refrigeration unit (13a, 13b) and the cascade unit (12) will be described, and then the operation of the refrigeration unit (13a, 13b) is stopped and the cascade unit ( The operation of the freezing operation that operates 12) will be described.
[0067]
<Refrigeration operation>
First, the operation in the high temperature side refrigerant circuit (20) will be described with reference to FIGS. FIG. 3 shows a refrigeration cycle in the high temperature side refrigerant circuit (20) on a Mollier diagram (pressure-enthalpy diagram). The symbols A to J in FIGS. 3 and 1 correspond to each other.
[0068]
The refrigerant in the state of point A is sucked into the compressors (22a, 22b) of the compression mechanism (21). The refrigerant at point A is compressed by the compressors (22a, 22b) and discharged in the state of point B. The refrigerant at point B is sent to the condenser (23). In the condenser (23), the refrigerant dissipates heat by exchanging heat with the outdoor air, and condenses to a point C state.
[0069]
The refrigerant at the point C is decompressed by the capillary tube (24) and then flows into the receiver (25). Here, the gas side electromagnetic valve (62) is intermittently opened and closed by the controller (70), and the receiver (25) is intermittently communicated with the suction side of the compression mechanism (21). Then, the refrigerant at the point C is depressurized by the pressure reduction in the capillary tube (24) and the opening / closing operation of the gas side solenoid valve (62) to be in the state of the point D. In the receiver (25), the refrigerant at the point D is separated into the liquid refrigerant at the point E and the gas refrigerant at the point I.
[0070]
The refrigerant in the state of point E is sent to the refrigerant heat exchanger (26) through the refrigerant pipe (33) and the liquid side connecting pipe (31). In the refrigerant heat exchanger (26), heat is exchanged between the refrigerant in the high temperature side refrigerant circuit (20) and the refrigerant in the low temperature side refrigerant circuit (50). Then, by this heat exchange, the refrigerant at point E absorbs heat from the refrigerant in the low-temperature side refrigerant circuit (50), and part of it evaporates to be in the state of point F.
[0071]
The refrigerant in the state of point F is distributed to the use side circuit (40a, 40b) of each refrigeration unit (13a, 13b). In each use side circuit (40a, 40b), the refrigerant at point F passes through the use side solenoid valve (64a, 64b) and is sent to the refrigeration evaporator (41a, 41b). At that time, the use side solenoid valves (64a, 64b) are opened and closed by the control operation of the controller (70). Accordingly, the refrigerant is intermittently supplied to the refrigeration evaporators (41a, 41b). Then, the refrigerant at point F is depressurized by opening / closing the use side solenoid valves (64a, 64b), and the state of point G is reached. It should be noted that a small-diameter valve may be adopted for the use side solenoid valve (64a, 64b) so as to obtain a certain amount of refrigerant pressure reducing action even when passing through the use side solenoid valve (64a, 64b).
[0072]
The controller (70) performs a predetermined control operation so that the refrigerant on the usage side circuit (40a, 40b) becomes saturated vapor at the outlet of the refrigeration evaporator (41a, 41b). Open and close the valves (64a, 64b). At this time, the control operation of the controller (70) is performed individually for each use side solenoid valve (64a, 64b) according to the operating state of each use side circuit (40a, 40b).
[0073]
The refrigerant in the state of point G is sent to the refrigeration evaporators (41a, 41b). In the refrigeration evaporators (41a, 41b), the refrigerant absorbs heat from the air inside the refrigerator and evaporates, resulting in a point H state. In the state of point H, the refrigerant is saturated steam. Then, the refrigerant in the state of point H is sent to the suction side of the compression mechanism (21).
[0074]
On the other hand, the gas refrigerant in the state of point I separated by the receiver (25) is depressurized by the opening / closing operation of the gas side electromagnetic valve (62) to be in the state of point J. Then, the refrigerant in the state of point J is sent to the suction side of the compression mechanism (21). Here, the refrigerant at point H and the refrigerant at point J are fed into the compression mechanism (21). Therefore, the compression mechanism (21) sucks the refrigerant in the state of point A, which is a mixture of the refrigerant at point H and the refrigerant at point J. In the high temperature side refrigerant circuit (20), the above cycle is repeated to perform the refrigeration cycle operation.
[0075]
Next, the operation in the low temperature side refrigerant circuit (50) will be described.
[0076]
The refrigerant discharged from the compressor (51) of the low temperature side refrigerant circuit (50) is sent to the refrigerant heat exchanger (26). As described above, the refrigerant heat exchanger (26) forms a cascade capacitor. In the refrigerant heat exchanger (26), the refrigerant in the low-temperature side refrigerant circuit (50) exchanges heat with the refrigerant in the high-temperature side refrigerant circuit (20) to dissipate heat and condense. The condensed refrigerant is decompressed by the expansion valve (52) and then sent to the freezing evaporator (53). In the freezing evaporator (53), the refrigerant evaporates by exchanging heat with the air in the freezer. The evaporated refrigerant is sucked into the compressor (51), compressed again, and this cycle is repeated.
[0077]
<Refrigeration operation>
During the refrigeration operation, the use side solenoid valves (64a, 64b) of the refrigeration units (13a, 13b) are closed, and the bypass solenoid valve (63) of the bypass pipe (35) is opened. Similarly to the above-described freezing and refrigeration operation, the refrigerant discharged from the compression mechanism (21) is condensed by the condenser (23), depressurized by the capillary tube (24), and the receiver (25) has an intermediate-pressure gas-liquid Two-phase refrigerant is stored. The receiver (25) is depressurized by opening / closing control of the gas side solenoid valve (62) of the decompression pipe (34). The liquid refrigerant flowing out from the lower end of the receiver (25) exchanges heat with the refrigerant in the low temperature side refrigerant circuit (50) via the refrigerant heat exchanger (26) and evaporates. The evaporated refrigerant is sucked into the suction side of the compression mechanism (21) through the bypass pipe (35) without passing through the refrigeration unit (13a, 13b). In the low-temperature side refrigerant circuit (50), the refrigerant circulates by the same action as the above-described freezing / refrigeration operation, and the inside of the freezer is cooled.
[0078]
<Control of liquid side solenoid valve, gas side solenoid valve, and bypass solenoid valve>
Here, the control operation performed by the controller (70) for the liquid side solenoid valve (61), the gas side solenoid valve (62) and the bypass solenoid valve (63) will be briefly described.
[0079]
The control operation of the liquid side solenoid valve (61) by the controller (70) is performed based on the temperature detected by the discharge temperature sensor (68). Specifically, the controller (70) repeats opening and closing of the liquid side solenoid valve (61) at predetermined time intervals. When the detected temperature of the discharge temperature sensor (68) exceeds a predetermined value, the time (open time) for holding the liquid side solenoid valve (61) in the open state is extended. In this state, it is considered that the degree of superheat of the gas refrigerant sucked by the compression mechanism (21) is increased. Therefore, the refrigerant heat exchanger (26) and the refrigeration evaporators (41a, 41b) from the receiver (25) to the refrigerant amount that can be evaporated by the refrigerant heat exchanger (26) and the refrigeration evaporators (41a, 41b). It can be judged that the amount of the refrigerant sent to is too small. Therefore, the opening time of the liquid side solenoid valve (61) is extended to increase the amount of liquid refrigerant flowing out from the receiver (25).
[0080]
The control operation of the gas side solenoid valve (62) by the controller (70) is performed based on the temperature detected by the liquid temperature sensor (67). Specifically, when the temperature detected by the liquid temperature sensor (67) is 20 ° C. or higher, the gas side solenoid valve (62) is opened, while when the temperature detected by the liquid temperature sensor (67) is 12 ° C. or lower, the gas side solenoid valve ( 62) is closed. The controller (70) maintains the temperature of the liquid refrigerant stored in the receiver (25) at about 15 ° C. by operating the gas side solenoid valve (62). Here, when the liquid refrigerant temperature in the receiver (25) becomes too low, the liquid refrigerant and the refrigerating machine oil are separated in the receiver (25). For this reason, the temperature of the liquid refrigerant in the receiver (25) is maintained at a predetermined value and is kept in a state where the refrigeration oil is dissolved in the liquid refrigerant, thereby avoiding the accumulation of the refrigeration oil in the receiver (25).
[0081]
Furthermore, the controller (70) also performs a control operation for the bypass solenoid valve (63). Specifically, during operation of the refrigeration unit (13a, 13b), the bypass solenoid valve (63) is held closed. On the other hand, when the two refrigeration units (13a, 13b) are thermo-off at the same time, the bypass solenoid valve (63) is repeatedly opened and closed at predetermined time intervals. In other words, when the use side solenoid valves (64a, 64b) of both refrigeration units (13a, 13b) are closed, the bypass solenoid valve (63) is opened and closed to ensure the refrigerant flow in the refrigerant heat exchanger (26). To do.
[0082]
The control of these solenoid valves (61, 62, 63) is also based on the idea of the inventors of the present application, and more specific control contents have already been filed in Japanese Patent Application No. 2000-33363.
[0083]
-Silent control at night-
Next, the silent silence control characteristic of the present embodiment will be described with reference to the flowcharts shown in FIGS.
[0084]
In the present embodiment, as described above, the 24-hour timer (71) is set using the oscillation circuit provided in the microprocessor of the controller (70). Then, based on the change in outdoor temperature within 24 hours detected by the timer (71), the morning time zone from the night is judged, and silent control is performed to suppress the driving noise during that time.
[0085]
Specifically, the controller (70) detects the maximum temperature and the minimum temperature every 24 hours detected by the timer (71), and calculates the average temperature for the 24 hours.
[0086]
The detection of the minimum temperature is always performed according to the flowchart of FIG. That is, in step ST1, it is determined whether or not the outdoor temperature detected by the outdoor temperature sensor (66) (this time data in FIG. 4) is lower than the minimum temperature Tmin so far. If the detected temperature is lower than the minimum temperature Tmin, the minimum temperature Tmin is updated in step ST2, and the timer To is started in step ST3. If it is determined in step ST1 that the detected temperature is not lower than the minimum temperature Tmin, the determination in step ST1 is repeated in order to perform the operation of this flowchart again.
[0087]
The detection of the maximum temperature is always performed according to the flowchart of FIG. That is, in step ST11, it is determined whether or not the outdoor temperature detected by the outdoor temperature sensor (66) is higher than the maximum temperature Tmax so far. If the detected temperature is higher than the maximum temperature Tmax, the maximum temperature Tmax is updated in step ST12. As a result of the determination in step ST11, if it is determined that the detected temperature is not higher than the maximum temperature Tmax, the operation returns to the start point of the operation of this flowchart and the operation in step ST11 is repeated again.
[0088]
When 24 hours elapses while performing the above detection, the average temperature Tave is obtained from the maximum temperature Tmax and the minimum temperature Tmin detected during the 24 hours based on the flowchart of FIG. That is, the average temperature Tave is obtained by dividing the sum of the maximum temperature Tmax and the minimum temperature Tmin by 2 in step ST21.
[0089]
When the maximum temperature Tmax, the minimum temperature Tmin, and the average temperature Tave are obtained in this manner, the silent operation control operation shown in the flowchart of FIG. 7 is executed. Silent operation control is performed as control for suppressing operation noise by controlling one or both of the outdoor fan (15) and the compression mechanism (21). During the silent control, the indoor fan (15) is controlled to reduce the air volume, and the compression mechanism (21) is operated by reducing the number of operating compressors (22a, 22b).
[0090]
First, in step ST31, the time from the start of the timer in step ST3 of FIG. 4 is determined. That is, it is determined whether the elapsed time is within 3 hours after the timer To is started. Then, until 3 hours have passed, the process proceeds to step ST32 to perform a silent operation, and further proceeds to step ST33, where the average temperature Tave calculated in FIG. 6 is compared with the detected temperature at that time. If the detected temperature at that time is equal to or higher than the average temperature Tave, the silent operation is terminated in step ST34 even before 3 hours have elapsed. If it is determined in step ST33 that the detected temperature is lower than the average temperature Tave, the process returns to step ST31 while continuing the silent operation.
[0091]
On the other hand, when it is determined in step ST31 that 3 hours have already elapsed since the timer start, it is determined in step ST35 whether 14 hours or more have elapsed since the timer start. If 14 hours have not yet elapsed, the silent operation is terminated in step ST36 and the process returns to the determination operation in step ST31.
[0092]
If it is determined in step ST35 that 14 hours have already elapsed, the process proceeds to step ST37, where it is determined whether or not the detected temperature at that time is lower than the average temperature Tave. If the detected temperature is lower than the average temperature Tave, the silent operation is started in step ST38 and the process returns to step ST31. If the detected temperature is higher than the average temperature Tave, the silent operation is ended.
[0093]
As is clear from the above description, in this embodiment, the minimum temperature Tmin, the maximum temperature Tmax, and the average temperature Tave are obtained every 24 hours, and from the time of the minimum temperature Tmin to the start from 3 hours to 14 hours later. The silent operation is performed only in the time zone excluding the time zone and in the time zone where the detected temperature is lower than the average temperature Tave of the previous day.
[0094]
Specifically, if the time of the minimum temperature Tmin is from 5:00 am to 7:00 am, it is determined that it is still early morning until 3 hours have passed or until the detected temperature exceeds the average temperature Tave. Will continue. Further, when 3 hours have passed from the time of the lowest temperature Tmin (from 8 am to 10 am), it is determined that the early morning time has passed, and 14 hours have passed since the time of the lowest temperature Tmin (afternoon From 7 o'clock to around 9 pm), silent operation is not performed because noise is not a problem.
[0095]
On the other hand, if the detected temperature falls below the average temperature Tave on the previous day after 14 hours have elapsed, the silent operation is started. That is, when the temperature is sufficiently lowered from 7 pm to 9 pm, it is determined that it is a time zone in which silent operation is necessary.
[0096]
In the flow chart of FIG. 7, the start and stop of the silent operation are switched if the level relationship between the detected temperature and the average temperature Tave is reversed after 3 hours and 14 hours from the start of the timer. When the detected temperature accidentally increases or decreases, control may be performed so as not to switch the start and stop of the silent operation. Specifically, the silent control may be performed only in a continuous time zone in which the detected temperature is lower than the reference temperature such as the average temperature Tave before 3 hours and 14 hours have elapsed since the timer start.
[0097]
-Effect of the embodiment-
As described above, in this embodiment, the average temperature Tave is calculated from the maximum temperature Tmax and the minimum temperature Tmin on the previous day, and whether or not the silent operation is necessary is constantly compared with the average temperature Tave and the detected outdoor temperature. Deciding. Therefore, it is not necessary to give the operation control means (70) a clock function, the oscillation circuit originally provided in the microprocessor of the operation control means (70), and the outdoor temperature generally provided in the outdoor unit (11). Since noise control can be performed from the sensor (66), it is possible to take measures against noise at night while suppressing an increase in cost.
[0098]
Note that if the compressor mechanism (21) and the outdoor fan (15) are controlled to perform a silent operation, the capacity of the refrigeration system (10) is slightly reduced, but during silent control, the temperature decreases at night. In particular, it is convenient to suppress a decrease in capacity in a cooling facility such as a refrigerator or a freezer as described in the above embodiment. In this case, at the time of silent control, the compression mechanism (21) and the outdoor fan (15) may be controlled within a range in which a reduction in performance does not become a problem and driving noise is reduced.
[0099]
In addition, when only one of the two compressors (22a, 22b) is operated during silent control at night, the noise caused by the compressor (22a, 22b) can be halved.
[0100]
In addition, since the detected temperature is lower than the average temperature Tave and the lowest temperature Tmin is the starting point, the silent control is performed only in the range before 3 hours and after 14 hours. Silent control can be reliably performed from night to morning while preventing a decrease in capacity during the daytime when noise is not a problem.
[0101]
Other Embodiments of the Invention
The present invention may be configured as follows with respect to the above embodiment.
[0102]
For example, although the refrigeration apparatus (10) according to the above embodiment is a two-way refrigeration apparatus, the application target of the present invention may be a one-way refrigeration apparatus. Further, the number of the refrigeration units (13a, 13b) in the high-temperature side refrigerant circuit (20) is not limited to a plurality, and may be one, or instead of providing two refrigeration units (13a, 13b), the refrigeration unit For example, one air conditioner indoor unit may be provided. Further, in the above embodiment, only one refrigeration unit (14) constituting the low temperature side refrigerant circuit (50) is provided, but a plurality of refrigeration units may be provided.
[0103]
In the above embodiment, the use side electromagnetic valve (64a, 64b) is provided in front of the evaporator (41a, 41b) of the refrigeration unit (13a, 13b) so as to depressurize the refrigerant. A circuit configuration of a general refrigeration cycle using an expansion valve instead of the valves (64a, 64b) may be used. As described above, in the present invention, the specific configuration of the refrigerant circuit can be arbitrarily changed, and the refrigerant circuit may be appropriately configured as necessary.
[0104]
Furthermore, in the above embodiment, the silent operation conditions are 3 hours before and 14 hours after the minimum temperature Tmin, but this time is not a condition, and the detected temperature is simply lower than the average temperature Tave on the previous day. The silent operation may be performed only on the condition. In that case, although the detection accuracy of the time zone in which the silent operation is performed is slightly lowered, it is possible to prevent noise in a generally required time zone. In addition, 3 hours and 14 hours, which are the set times, can be appropriately adjusted according to the region where the refrigeration apparatus is installed.
[0105]
In the above embodiment, the oscillation circuit of the microprocessor is used as the timer (71). However, any timer that can detect only the passage of time can be used. In this case, a clock that recognizes the time itself is used. Since no function is required, an increase in cost can be suppressed.
[0106]
In the above embodiment, the average temperature Tave is used as a reference temperature for comparison with the detected temperature. However, the reference temperature is not limited to the average temperature Tave, and may be temperature data set according to conditions such as weather conditions and seasons. Further, even when the average temperature Tave is used, the average temperature Tave of the maximum temperature Tmax and the minimum temperature Tmin is not limited, and temperature data measured several times in one day may be averaged.
[0107]
Further, in the above embodiment, when the compressors (22a, 22b) are controlled, the number of operating units is reduced. However, for example, the operating speed may be suppressed by reducing the rotational speed by inverter control. .
[Brief description of the drawings]
FIG. 1 is a piping system diagram of a high-temperature side refrigerant circuit in a refrigeration apparatus according to an embodiment of the present invention.
FIG. 2 is a piping system diagram of a low-temperature side refrigerant circuit in the refrigeration apparatus according to the embodiment of the present invention.
FIG. 3 is a Mollier diagram showing a refrigeration cycle in the high temperature side refrigerant circuit of FIG. 1;
FIG. 4 is a flowchart showing a minimum temperature detection operation.
FIG. 5 is a flowchart showing a maximum temperature detection operation.
FIG. 6 is a flowchart showing an average temperature calculation operation.
FIG. 7 is a flowchart showing an operation of silent operation control.
[Explanation of symbols]
(10) Refrigeration equipment
(11) Outdoor unit
(12) Cascade unit
(13a, 13b) Refrigeration unit
(14) Refrigeration unit
(15) Outdoor fan
(20) High temperature side refrigerant circuit
(21) Compression mechanism
(22a, 22b) Compressor
(23) Condenser (Outdoor heat exchanger)
(26) Refrigerant heat exchanger (cascade condenser)
(41a, 41b) Refrigerator evaporator (evaporator)
(50) Low temperature side refrigerant circuit
(66) Outdoor temperature sensor
(70) Controller (operation control means)
(71) Timer

Claims (11)

An outdoor unit (11) having a compression mechanism (21), an outdoor heat exchanger (23), and an outdoor fan (15), an outdoor temperature sensor (66) for detecting the outdoor temperature, and operation control means for controlling each device (70) and a refrigeration apparatus comprising:
The operation control means (70) includes a timer (71), and in a time period when the temperature detected by the outdoor temperature sensor (66) is lower than a predetermined reference temperature within approximately 24 hours starting from a predetermined time. Configured to suppress driving noise,
The operation control means (70) is configured by a microprocessor, and the timer (71) is configured to be capable of detecting 24 hours using an oscillation circuit of the microprocessor .
The refrigeration apparatus , wherein the predetermined reference temperature is a temperature calculated based on data of a temperature detected by the outdoor temperature sensor (66) . The refrigeration apparatus according to claim 1, wherein the predetermined reference temperature is an average temperature calculated from the temperature detected by the outdoor temperature sensor (66) within 24 hours detected by the timer (71) . The refrigeration apparatus according to claim 2, wherein the predetermined reference temperature is an average temperature calculated from the highest temperature and the lowest temperature detected by the outdoor temperature sensor (66) within 24 hours detected by the timer (71). The refrigeration apparatus according to claim 1 , wherein the predetermined reference temperature is a set temperature according to operating conditions . The refrigeration apparatus according to any one of claims 1 to 4, wherein the operation control means (70) is configured to control the outdoor fan (15) to suppress operation noise . The refrigeration apparatus according to any one of claims 1 to 4 , wherein the operation control means (70) is configured to control the compression mechanism (21) to suppress operation noise. Operation control means (70), an outdoor fan (15) and the compression mechanism (21) and the control to the refrigeration apparatus of any one according of claims 1 and is configured to suppress 4 operating sound. A compression mechanism (21) is configured with a plurality of compressors (22a, 22b ) in the outdoor unit (11) ,
The refrigeration apparatus according to claim 6 or 7, wherein the operation control means (70) is configured to reduce the number of operating compressors (22a, 22b) when performing control to suppress operation noise . The operation control means (70) is a period in which the detected temperature is lower than a predetermined reference temperature before the first predetermined time and after the second predetermined time within 24 hours starting from the time of the lowest temperature. The refrigeration apparatus according to any one of claims 1 to 8 , wherein the belt is configured to perform control for suppressing driving noise . Operation control means (70), as a starting point the time of the minimum temperature, the first predetermined time is set to 3 hours, a second refrigeration system of claim 9, wherein the predetermined time is set to 14 hours . The operation control means (70) continuously detects the detected temperature lower than the predetermined reference temperature within 24 hours starting from the time of the lowest temperature before the first predetermined time and after the second predetermined time. The refrigeration apparatus according to claim 9 or 10, wherein the refrigeration apparatus is configured to perform control for suppressing operation noise during the time period .

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