JP2008075964A - Defrosting device of cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a defrosting device capable of effectively and efficiently melting and removing the frost attached to an evaporator without being affected by the condition of outside air and the condition of a cooled space. <P>SOLUTION: The cooling device 4 cooling a storage compartment 3 by cooling action by the evaporator 5 constituting a refrigerant circuit 40 with a compressor 18, and melting and removing the frost attached to the evaporator 5 by a heater 26, comprises an evaporator temperature sensor 44 for detecting a prescribed defrost termination temperature of the evaporator 5, and a control device C for controlling the heater 26 on the basis of the output of the sensor 44, the control device C starts the defrosting of the evaporator 5 by the heater 26 at a prescribed timing, terminates the defrosting at a time point when a temperature of the evaporator 5 is increased to a defrost termination temperature Tde, and lowers the defrost termination temperature Tde when it is judges that an operating efficiency of the compressor 18 before the start of defrosting is lower than a prescribed lower limit value. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a defrosting device for a cooling device that cools a space to be cooled by a cooling action by an evaporator that constitutes a refrigerant circuit together with a compressor, and that melts and removes frost attached to the evaporator by a defrosting means. .

  Conventionally, this kind of cooling device defrosting device is used for a cooling device installed in a commercial refrigerator, for example, and the cooling device constitutes the cooling device by performing a cooling operation for a long time. The evaporator forms frost. The defrosting device performs a defrosting operation for melting and removing frost attached to the evaporator in order to avoid a decrease in cooling efficiency due to frosting of the evaporator.

  Conventionally, the defrosting means used in the cooling device is an electric heater that directly heats the evaporator, a method that causes high-temperature refrigerant to flow into the evaporator, and a method that does not supply refrigerant to the evaporator, including stopping the compressor. In addition to stopping the supply of refrigerant to the evaporator, there is a method of always operating a blower for circulation in the warehouse.

  In any case, the defrosting means starts the defrosting operation when the time set in advance within the day is reached by the control device or when the total operation time of the compressor reaches a predetermined time. A defrosting start signal was issued and the defrosting operation was executed for a certain time.

However, when the set temperature in the warehouse, which is the space to be cooled, or the set temperature of the evaporator is high, the operating rate of the cooling device is lowered and frosting is less likely to occur in the evaporator. Therefore, the defrosting means provided in the cooling storage device described in Patent Document 1 does not perform the defrosting operation when the set temperature in the storage chamber is equal to or higher than a predetermined reference value. Energy waste due to wasteful defrosting at the time of setting is suppressed.
JP 2003-322458 A

  On the other hand, frost formation on the evaporator occurs when moisture contained in the air in the space to be cooled condenses on the evaporator surface due to a temperature difference, and the moisture becomes frost due to the temperature of the evaporator itself. is there. Further, every time an article is delivered to the cooled space, the door that closes the cooled space is opened, and the outside air enters the cooled space, so that the evaporator easily forms frost. .

  Therefore, the amount of frost formation on the evaporator changes due to changes in the outside air temperature and outside air humidity. For example, in the situation where the outside air temperature is low and dry as in winter, the amount of frost formation is small, and in the conventional defrosting operation, a so-called premature cutting state in which defrosting starts and ends immediately is repeated. Energy waste due to wasteful defrosting and deterioration of articles stored in the space to be cooled become problems.

  On the other hand, in a situation where the outside air temperature is high and humidity is high as in summer, frost formation becomes significant, and the frost blockage of the evaporator occurs in the later stage of the cooling operation, and the cooling air circulation to the cooled space is hindered and the cooled space. When the temperature of the product rises and the stored article is a food, there is a problem that the freshness deterioration becomes remarkable.

  However, in the defrosting operation described in Patent Document 1 as described above, it is not possible to remove the frost generated in the evaporator according to the outside air temperature or the humidity of the space to be cooled. Therefore, even when hot and humid outdoor air in the summer enters the cooled space, it is necessary to perform a defrosting operation according to the hot and humid conditions in the summer in order to reliably remove the frost attached to the evaporator. was there.

  Therefore, in the case of dry air conditions with relatively low temperatures such as in winter, the defrosting operation is performed longer than necessary, so that the so-called premature cutting state as described above is repeated, and wasteful defrosting causes There is a problem that waste of energy and deterioration of articles stored in the cooled space occur.

  Therefore, the present invention has been made to solve the conventional technical problem, and is effectively and efficiently attached to the evaporator without being affected by the state of the outside air or the state of the space to be cooled. Provided is a defrosting device that makes it possible to melt and remove frost.

  The defrosting device of the present invention is a cooling device that cools a space to be cooled by a cooling action by an evaporator that constitutes a refrigerant circuit together with a compressor, and that melts and removes frost attached to the evaporator by a defrosting means. The defrosting end temperature detecting means for detecting the predetermined defrosting end temperature and the control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means, wherein the control means has a predetermined timing. Then, the defrosting of the evaporator by the defrosting means is started, and when the temperature of the evaporator rises to the defrosting end temperature, the defrosting is completed, and the operation rate of the compressor before starting the defrosting or constant When it is determined that the average value of the operation rate during the period is equal to or lower than a predetermined lower limit value, the defrosting end temperature is lowered.

  The defrosting device of the invention of claim 2 is a cooling device for cooling the space to be cooled by a cooling action by an evaporator constituting a refrigerant circuit together with a compressor, and for melting and removing frost attached to the evaporator by a defrosting means. The defrosting end temperature detecting means for detecting the predetermined defrosting end temperature of the evaporator, and the control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means, the control means comprising: The defrosting of the evaporator by the defrosting means is started at a predetermined timing, and when the temperature of the evaporator rises to the defrosting end temperature, the defrosting is finished, and the operation rate of the compressor before the start of the defrosting, Alternatively, when it is determined that the difference between the average value of the operation rate in a certain period and the operation rate immediately after the previous defrost is equal to or less than a predetermined lower limit value, the defrost end temperature is reduced. To do.

  According to a third aspect of the present invention, there is provided a defrosting apparatus according to any one of the above-mentioned inventions, comprising door opening / closing detection means for detecting an opening / closing state of a door that closes the space to be cooled in an openable / closable manner. The operation rate when the door to be opened and closed is a predetermined number of times or more is excluded from the determination.

  According to the present invention, in the cooling device that cools the space to be cooled by the cooling action of the evaporator that constitutes the refrigerant circuit together with the compressor, and that melts and removes the frost attached to the evaporator by the defrosting means, The defrosting end temperature detecting means for detecting the defrosting end temperature of the defrosting, and the control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means, the control means removing at a predetermined timing. Since the defrosting of the evaporator by the frosting means is started and the defrosting is finished when the temperature of the evaporator rises to the defrosting end temperature, the fact that the frost melting and removal attached to the evaporator is finished is It is possible to make a determination based on the temperature of the evaporator, and the defrosting operation according to the amount of frost on the evaporator can be appropriately executed.

  As a result, even when the amount of frost on the evaporator is small, the defrosting operation can be terminated at an appropriate timing, and the inconvenience that energy is wasted can be suppressed and the object to be cooled is wasted. It is possible to avoid the inconvenience of increasing the temperature of the space. For this reason, it is possible to suppress the disadvantage that the temperature of an article such as a food stored in the space to be cooled rises and the freshness deteriorates.

  On the contrary, even when the amount of frost formation on the evaporator is large, the defrosting operation can be terminated when the defrosting of the evaporator is completed with certainty, so that the frost remains on the evaporator. Therefore, it is possible to avoid the inconvenience of remaining until the next defrosting.

  In addition, when the control unit determines that the operation rate of the compressor before the start of defrosting or the average value of the operation rate during a certain period is equal to or lower than a predetermined lower limit value, the control unit decreases the defrosting end temperature. Therefore, if the operating rate of the compressor before the start of defrosting or the average value of the operating rate in a certain period is low and there is no or little frosting on the evaporator, it will be earlier than the normal defrosting operation. It is possible to end the defrosting operation.

  As a result, it is possible to reduce the influence of the defrosting on the space to be cooled, further improve the cooling efficiency, and further suppress the temperature rise of the stored articles. Become.

  According to the invention of claim 2, in the cooling device that cools the space to be cooled by the cooling action of the evaporator that constitutes the refrigerant circuit together with the compressor, and melts and removes the frost attached to the evaporator by the defrosting means. A defrosting end temperature detecting means for detecting a predetermined defrosting end temperature of the chiller, and a control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means. Since the defrosting of the evaporator by the defrosting means is started at the timing and the defrosting is finished when the temperature of the evaporator rises to the defrosting end temperature, the frost adhering to the evaporator is similar to the above invention. It is possible to determine the completion of the melting and removal based on the temperature of the evaporator, and it is possible to appropriately execute the defrosting operation according to the amount of frost formation on the evaporator.

  As a result, even when the amount of frost on the evaporator is small, the defrosting operation can be terminated at an appropriate timing, and the inconvenience that energy is wasted can be suppressed and the object to be cooled is wasted. It is possible to avoid the inconvenience of increasing the temperature of the space. For this reason, it is possible to suppress the disadvantage that the temperature of an article such as a food stored in the space to be cooled rises and the freshness deteriorates.

  On the contrary, even when the amount of frost formation on the evaporator is large, the defrosting operation can be terminated when the defrosting of the evaporator is completed with certainty, so that the frost remains on the evaporator. Therefore, it is possible to avoid the inconvenience of remaining until the next defrosting.

  Further, the control means is such that the difference between the operation rate of the compressor before the start of defrosting, or the average value of the operation rate in a certain period, and the operation rate immediately after the previous defrosting is equal to or less than a predetermined lower limit value. When it is determined that the defrosting end temperature is lowered, the difference between the operation rate of the compressor before the start of defrosting or the average value of the operation rate in a certain period and the operation rate immediately after the previous defrosting is small. When there is no or little frost formation on the evaporator, the defrosting operation can be terminated earlier than the normal defrosting operation.

  As a result, it is possible to reduce the influence of the defrosting on the space to be cooled, further improve the cooling efficiency, and further suppress the temperature rise of the stored articles. Become.

  According to the invention of claim 3, in addition to each of the above inventions, the apparatus further comprises door opening / closing detection means for detecting an opening / closing state of the door that opens and closes the space to be cooled, and the control means is detected by the door opening / closing detection means. By excluding the operating rate when the door is opened and closed more than a predetermined number of times from the judgment, excluding changes in the operating rate of the compressor due to frequent door opening and closing, the operation of the compressor It is possible to correct the defrosting end temperature using the rate as an index. Thereby, it becomes possible to implement | achieve appropriate defrost according to the frost formation condition to an evaporator still more reliably.

  The defrosting device of the present invention is used for cooling a space to be cooled, such as a commercial / household refrigerator, a commercial / household refrigerator, a showcase, an open showcase, a prefabricated refrigerator, a prefabricated freezer, an air conditioner. It is used for defrosting of the cooling device R to be used. In this embodiment, an embodiment of the present invention will be described in detail below with reference to the drawings, taking a cooling storage R as an example of the refrigerator / freezer. FIG. 1 is a vertical side view of a cooling storage R to which the present invention is applied, and FIG. 2 is a vertical side view of the cooling storage R.

  The cooling storage R in the present embodiment is a vertical business refrigerator installed in a hotel or restaurant kitchen, and includes a heat insulating box 2 as a main body that opens to the front. Inside the heat insulation box 2, there is a storage chamber 3 as a space to be cooled, and in the upper portion of the storage chamber 3, a fan 6 is attached in the vicinity of the evaporator 5 of the cooling device 4 and the evaporator 5, Thereby, the inside of the storage chamber 3 is cooled to a predetermined temperature. In the figure, 26 attached to the lower part of the evaporator 5 is a heater (electric heater) that functions as a defrosting means in the present embodiment, and energization control is performed by a control device C described later in detail. Reference numeral 44 denotes an evaporator temperature sensor for detecting the temperature of the evaporator 5 (defrosting end temperature detecting means for detecting the defrosting end temperature described in detail later).

  Furthermore, 7 attached below the evaporator 5 and the blower 6 is a drain pan for receiving drain water generated from the evaporator 5, and is a partition between the cooling chamber 8 to which the evaporator 5 is attached and the inside of the storage chamber 3. Also served. The drain pan 7 is filled with the blower 6 and is formed with a cold air inlet (not shown), and the rear side is open. Thereby, the cold air drawn into the cooling chamber 8 from the storage chamber 3 from the blower 6 is discharged from the rear of the cooling chamber 8 after heat exchange with the evaporator 5. In addition, an internal temperature sensor 27 for detecting the temperature in the storage chamber 3 is provided in the vicinity of the cold air inlet of the drain pan 7.

  Here, a drainage opening (not shown) is formed behind the drain pan 7, and one end of a cylindrical drain socket 9 having an opening having substantially the same size as the drainage opening is attached to the drainage opening. Here, after one end is connected to the drainage opening, the drain socket 9 is formed to incline at a predetermined angle toward the rear lower side and then extend vertically downward. An opening (not shown) for inserting the drain socket 9 is formed in advance on the upper back surface of the heat insulation box 2, that is, the back surface of the heat insulation box 2 corresponding to the position where the drain socket 9 is attached.

  Further, a drain hose storage portion 10 that is recessed inward from the upper end to the lower end is formed on the back surface of the heat insulating box 2. In addition, 11 provided in the four corners of the bottom face of the heat insulation box 2 in the figure is a support member provided in order to maintain a predetermined interval between the floor surface of the place where the cooling storage R is installed and the bottom face of the heat insulation box 2.

  And the end of the drain hose 12 comprised with a flexible material is connected to the lower end of the drain socket 9 located in the outer back surface of the heat insulation box 2. As shown in FIG. The drain hose 12 is lowered along the drain hose storage portion 10 formed on the back surface of the heat insulation box body 2 and then drawn out from the bottom rear portion of the heat insulation box body 2 to the front bottom portion. It is attached downward with the opening. Thereby, drain water discharged from the drain pan 7, that is, frost after being melted by a defrosting operation as will be described in detail later, can be drained to the outside through the drain socket 9 and the drain hose 12.

  On the other hand, a machine room 17 is defined on the top surface of the heat insulating box 2 by a front panel 15 and a panel 16 constituting both side faces and a rear face, and a compressor constituting the cooling device 4 is formed in the machine room 17. 18, a condenser 19, and the like are installed, and together with the evaporator 5, a known refrigerant circuit of the cooling device 4 is configured. That is, as shown in the refrigerant circuit diagram of FIG. 3, the cooling device 4 includes the compressor 18, the condenser 19, a liquid electromagnetic valve 37 as a valve device, a dryer 38, and a capillary tube 39 as a pressure reducing device. And the evaporator 5 are sequentially connected in an annular manner to form a refrigerant circuit 40. 2 and 3, reference numeral 20 denotes a condenser blower.

  In addition, the front opening 22 of the storage chamber 3 (the heat insulating box 2) is vertically divided at the center by a lateral partition 23. The upper and lower openings 22 of the storage chamber 3 partitioned by the inner partition 23 are closed by two sets of double doors (insulating doors) 24 and 24 so as to be freely opened and closed. The door 24 or the heat insulating box 2 to which the door 24 is attached is provided with a door opening / closing sensor (door opening / closing detection means) 28 for detecting the opening / closing state of the door 24.

  On the other hand, a rear shelf column 30 is provided in the center of the back of the storage chamber 3 in the vertical direction. Further, on both side surfaces of the storage chamber 3, a plurality of engagement holes 31A (only the shelf column 31 is shown) are formed in the front and rear portions and extend vertically. In addition, a plurality of shelves 32 are installed on the shelf columns 31 above and below the storage chamber 3.

  Here, a partition member 33 is provided on both sides of the rear shelf column 30 and on the back surface of the storage chamber 3 with a predetermined distance from the back surface. The partition member 33 is a hard synthetic resin column member formed to extend from above the upper ends of the rear shelf columns 30 and 31 to below the lower ends of the rear shelf columns 30 and 31. . A cold air duct 34 having an upper end and a lower end is formed between the partition member 33 and the rear surface of the storage chamber 3. In the figure, reference numeral 35 denotes a floor.

  Next, the control device C of the present embodiment will be described with reference to the electric block diagram of FIG. The control device C is composed of a general-purpose microcomputer, and on this input side, a controller 41 for enabling the temperature in the storage chamber 3 to be arbitrarily set, the internal temperature sensor 27, and the The door opening / closing sensor 28, the temperature of the environment where the cooling storage R is installed, that is, the outside air temperature sensor (outside air temperature detecting means) 42 for detecting the outside air temperature, and the defrosting end temperature of the evaporator 5 are detected. An evaporator temperature sensor 44 is connected to this. Further, on the output side of the control device C, the compressor 18, the condenser blower 20, the liquid electromagnetic valve 37, the blower 6 used for the cold air circulation in the storage chamber 3, and a heater constituting defrosting means. 26 etc. are connected. The control device C has a built-in memory 43 as a storage means and a timer 45 as a time limit means.

  With the above configuration, the cooling operation of the cooling device 4 will be described. When the operation of the compressor 18 is started, the high-temperature and high-pressure gas refrigerant discharged from the refrigerant pipe on the discharge side of the compressor 18 flows into the condenser 19. Here, the sufficiently condensed and liquefied refrigerant flows into the capillary tube 39 through the liquid electromagnetic valve 37 and the dryer 38 because the liquid electromagnetic valve 37 is opened by the control device C. The liquid refrigerant that has flowed into the capillary tube 39 is decompressed and then flows into the evaporator 5. And the refrigerant | coolant which flowed into the evaporator 5 installed in the cooling chamber 8 evaporates, takes heat from the circumference | surroundings, and exhibits a cooling effect | action. The cool air exchanged with the evaporator 5 is circulated in the storage chamber 3 by the blower 6 disposed in the cooling chamber 8 to cool the interior of the storage chamber 3 to a predetermined temperature. Then, the refrigerant discharged from the evaporator 5 returns to the compressor 18.

  At this time, the control device C controls the operation and stop of the compressor 18 based on the detection output of the internal temperature sensor 27, and cools so that the temperature in the storage chamber 3 maintains a predetermined temperature. In addition, the timer 45 built in the control apparatus C shall count the said cooling time from the time of starting cooling operation.

  On the other hand, the cooling device 4 continuously performs the cooling operation as described above, so that the evaporator 5 is frosted. Therefore, the control device C performs the defrosting operation. Hereinafter, the defrosting operation will be described in detail with reference to FIGS. 5 and 6. FIG. 5 is a flowchart of the defrosting operation, and FIG. 6 is a flowchart of the defrosting end temperature correction. First, in step S1, the control device C determines whether or not 6 hours have elapsed since the start of the cooling operation in a predetermined defrost cycle, in this embodiment. Here, when the cooling operation has not passed the defrost cycle, the cooling operation is continued as it is. On the other hand, when the time from the start of the cooling operation has passed the defrost cycle, the process proceeds to step S2, a defrost start signal is generated, and the defrost operation is started.

  In this embodiment, since the defrosting means is constituted by the heater 26 provided in the evaporator 5, the operation of the compressor 18 and the blower 6 is stopped and the heater 26 is energized. Thaw and remove the attached frost.

  Next, the control device C proceeds to step S3, and determines whether or not the temperature detected by the evaporator temperature sensor 44 is equal to or higher than a predetermined defrosting end temperature Tde temperature. Here, when the temperature detected by the evaporator temperature sensor 44 is lower than the defrosting end temperature Tde, the defrosting operation is performed as it is, and in this embodiment, the energization to the heater 26 is closed. On the other hand, when the temperature detected by the evaporator temperature sensor 44 is equal to or higher than the defrosting end temperature Tde, the process proceeds to step S4, a defrosting end signal is generated, and the defrosting operation is ended. Then, a cooling start signal is generated to return to the cooling operation.

  Accordingly, it is possible to determine that the melting and removal of the frost attached to the evaporator 5 has been completed by detecting the temperature of the evaporator 5, and the defrosting operation according to the amount of frost applied to the evaporator 5. Can be executed appropriately. Therefore, even when the amount of frost on the evaporator 5 is small, the defrosting operation can be terminated at an appropriate timing, and the inconvenience of wasting energy can be suppressed, and the object to be cooled is wasted. It is possible to avoid the inconvenience of increasing the temperature in the storage chamber 3 as a space. Therefore, the inconvenience that the product temperature of articles such as food stored in the storage chamber 3 rises and the freshness deteriorates can be suppressed.

  On the other hand, even when the amount of frost on the evaporator 5 is large, the defrosting operation can be ended when the defrosting of the evaporator 5 is completed with certainty. It is possible to avoid the inconvenience of remaining until the next defrosting.

  On the other hand, the control device C executes correction control of the defrosting end temperature Tde at all times or every predetermined time. In the correction control, first, in step S5, the control device C, based on the detection output of the door opening / closing sensor 28, opens / closes the door 24 per predetermined time, for example, between several minutes to one hour. The data regarding this is taken in, and it is determined whether the door opening / closing frequency is larger or smaller than the predetermined frequency A. When the door opening / closing frequency is larger than the predetermined frequency A, the process proceeds to step S7, the door opening / closing flag is set, and then the process proceeds to step S8. On the other hand, when the door opening / closing frequency is less than the predetermined frequency A, the process proceeds to step S6, and after resetting the door opening / closing flag, the process proceeds to step S8.

  In step S8, the control device C determines whether to correct the defrosting end temperature Tde. This determination method includes the following determination methods 1 to 4, and any of these cases may be used.

(Judgment method 1)
The control device C determines whether or not the door opening / closing flag is set, and if the door opening / closing flag is set, that is, if the door opening / closing number of times per predetermined time is greater than the predetermined number of times, a step is performed. It progresses to S10 and the judgment which does not correct | amend defrost end temperature Tde is performed. On the other hand, when the door opening / closing flag is reset, that is, when the number of times the door is opened and closed per predetermined time is less than the predetermined number, the operation rate DR1 is calculated from the thermocycle of the compressor 18 during the cooling operation. To do. Specifically, based on the detection output of the internal temperature sensor 27, when the internal temperature reaches a predetermined ON temperature, the compressor 18 is turned on to cool the interior of the storage chamber 3. When the temperature in the storage chamber 3 reaches a predetermined OFF temperature due to the cooling, the compressor 18 is turned off. Thereafter, the temperature in the storage chamber 3 rises again, and the period until the internal temperature reaches the ON temperature and the compressor 18 is turned on is defined as one cycle. The operation ratio of the compressor 18 in one cycle is defined as the operation rate.

  Here, the control device C stores a predetermined lower limit value DRmin in the memory 43, compares the DRmin with the currently calculated operation rate DR1 of the compressor 18, and the current operation rate DR1 is a predetermined lower limit value. When it is determined that the value has become equal to or less than the value DRmin, the process proceeds to step S9, correction for decreasing the defrosting end temperature Tde is performed, and this is reflected in the defrosting end determination at the next defrosting operation.

  Thereby, when the operation rate DR1 of the compressor 18 before the start of defrosting is low and lower than the predetermined lower limit value DRmin, the defrost end temperature is lowered and the defrost end is lower than the initial defrost end temperature Tde. Since it is possible to determine the end of the defrosting at the temperature Tde, if there is no or little frosting on the evaporator 5, the defrosting operation should be terminated earlier than the normal defrosting operation. Is possible. Accordingly, it is possible to reduce the influence of defrosting on the storage chamber 3, to further improve the cooling efficiency, and to further suppress the temperature rise of the stored articles. Become.

  On the contrary, when the amount of frost formation on the evaporator 5 is large and the operation rate DR of the compressor 18 is higher than the predetermined lower limit value DRmin, the defrosting operation is performed based on the initial defrosting end temperature Tde. Therefore, the defrosting of the evaporator 5 can be performed smoothly, and an efficient defrosting operation and a cooling operation can be realized.

  Accordingly, the defrosting end temperature Tde of the evaporator 5 is corrected using the operation rate of the compressor 18 as an index, and the end timing of the defrosting operation is determined based on the defrosting end temperature Tde. Appropriate defrosting according to frost conditions can be realized.

(Judgment method 2)
The control device C calculates the operation rate DR1 from the thermocycle of the compressor 18 during the execution of the cooling operation, similarly to the determination method 1 described above. Here, in order to calculate the average value DRav of the operation rate of the compressor 18 in a certain period, the operation rate DR1 of the compressor 18 is fetched for a predetermined number of times, for example, 10 times (DR1 to DR10) for every predetermined time. The data for 10 times is divided by the number of times (here, 10 times) to calculate the average value DRav of the operation rate. In this case, when the door 24 is opened and closed a predetermined number of times or more and the door opening / closing flag is set, the operating rate of the compressor 18 is caused by the opening / closing of the door 24. Therefore, the operation rate when the door 24 is opened and closed is excluded from the data used for calculating the average value of the operation rate.

  Here, the control device C stores a predetermined lower limit value DRmin in the memory 43, compares the DRmin with the currently calculated average value DRav of the operating rate of the compressor 18, and the average value DRav is a predetermined value. When it is determined that the value is lower than the lower limit value DRmin, the process proceeds to step S9, where correction for lowering the defrosting end temperature Tde is executed, and reflected in the defrosting end determination at the next defrosting operation.

  Thereby, when the average value DRav of the operation rate in the fixed period of the compressor 18 before the start of defrosting is low and lower than the predetermined lower limit value DRmin, the defrost end temperature is lowered and the initial defrost end temperature Tde Since it is possible to determine the end of the defrosting at a lower defrosting end temperature Tde, if there is no or little frosting on the evaporator 5, the defrosting is performed earlier than the normal defrosting operation. It is possible to end the frost operation. Accordingly, it is possible to reduce the influence of defrosting on the storage chamber 3, to further improve the cooling efficiency, and to further suppress the temperature rise of the stored articles. Become.

  On the contrary, when the amount of frost formation on the evaporator 5 is large and the operation rate DRav of the compressor 18 in a certain period is higher than a predetermined lower limit value DRmin, the initial defrosting end temperature Tde is used as a reference. Since the end time of the defrosting operation is determined, the evaporator 5 can be defrosted smoothly, and an efficient defrosting operation and a cooling operation can be realized.

  Accordingly, the defrosting end temperature Tde of the evaporator 5 is corrected using the operation rate of the compressor 18 as an index, and the end timing of the defrosting operation is determined based on the defrosting end temperature Tde. Appropriate defrosting according to frost conditions can be realized.

(Judgment method 3)
The control device C calculates the operation rate DR0 of the compressor 18 in a state where there is no frost from the thermocycle of the compressor 18 in the cooling operation started immediately after the previous defrosting operation, and stores this operation rate DR0 in the memory 43. Remember it. Then, it is determined whether or not the door opening / closing flag is set, and if the door opening / closing flag is set, that is, if the number of door opening / closing per certain time is larger than the predetermined number of times, the process goes to step S10. The process proceeds to determine that the defrosting end temperature Tde is not corrected. On the other hand, when the door opening / closing flag is reset, that is, when the number of times of door opening / closing per certain time is less than the predetermined number of times, the operating rate is determined from the thermocycle of the current compressor 18 in the same manner as in the determination method 1 described above. DR1 is calculated.

  Here, the control device C stores the lower limit value Amin of the difference A between the operation rate DR0 of the compressor 18 immediately after the defrosting operation and the calculated operation rate of the compressor 18 in the memory 43, and the operation When the difference A between the rate DR0 and the currently calculated operation rate DR1 of the compressor 18 is compared with the lower limit value Amin, and when it is determined that the difference A is less than or equal to the lower limit value Amin, the process proceeds to step S9. Correction for lowering the defrosting end temperature Tde is executed and reflected in the defrosting end determination at the next defrosting operation.

  Accordingly, when it is determined that the difference A between the operation rate DR1 of the compressor 18 before the start of the defrosting and the operation rate DR0 immediately after the previous defrosting is equal to or less than the predetermined lower limit value Amin, the defrosting end temperature Tde The defrosting end can be determined at the defrosting end temperature Tde lower than the initial defrosting end temperature Tde. Therefore, the operating rate DR1 of the compressor 18 before the start of the defrosting and the previous defrosting end temperature Tde can be determined. When the difference A from the operation rate DR0 immediately after defrosting is small and there is no or little frost formation on the evaporator 5, the defrosting operation can be terminated earlier than the normal defrosting operation. Become.

  Thereby, it becomes possible to reduce the influence on the inside of the storage chamber 3 by defrosting, it is possible to further improve the cooling efficiency, and to further suppress the temperature rise of the stored articles. It becomes.

  On the contrary, when the amount of frost on the evaporator 5 is large and the difference A between the operating rate DR1 of the compressor 18 and the operating rate DR0 immediately after the previous defrosting is higher than a predetermined lower limit value Amin. Since the end time of the defrosting operation is determined based on the initial defrosting end temperature Tde, the evaporator 5 can be defrosted smoothly, and an efficient defrosting operation and a cooling operation can be performed. Can be realized.

  Accordingly, the defrosting end temperature Tde of the evaporator 5 is corrected using the operation rate of the compressor 18 as an index, and the end timing of the defrosting operation is determined based on the defrosting end temperature Tde. Appropriate defrosting according to frost conditions can be realized.

(Judgment method 4)
The control device C calculates the operation rate DR0 of the compressor 18 in a state where there is no frost from the thermocycle of the compressor 18 in the cooling operation started immediately after the previous defrosting operation, and stores this operation rate DR0 in the memory 43. Remember it. Then, the operating rate DR1 is calculated from the current thermocycle of the compressor 18 in the same manner as in the determination method 1 described above. Here, in order to calculate the average value DRav of the operation rate of the compressor 18 in a certain period, the operation rate DR1 of the compressor 18 is fetched for a predetermined number of times, for example, 10 times (DR1 to DR10) for every predetermined time. The data for 10 times is divided by the number of times (here, 10 times) to calculate the average value DRav of the operation rate. In this case, when the door 24 is opened and closed a predetermined number of times or more and the door opening / closing flag is set, the operating rate of the compressor 18 is caused by the opening / closing of the door 24. Therefore, the operation rate when the door 24 is opened and closed is excluded from the data used for calculating the average value of the operation rate.

  Here, the control device C stores the lower limit value Amin of the difference A between the operation rate DR0 of the compressor 18 immediately after the defrosting operation and the calculated operation rate of the compressor 18 in the memory 43, and the operation When the difference A between the rate DR0 and the average value DRav of the operation rate of the compressor 18 currently calculated is compared with the lower limit value Amin, and when it is determined that the difference A is less than or equal to the lower limit value Amin, step S9 It progresses to and the correction | amendment which lowers defrost end temperature Tde is performed, and it is reflected in the defrost end determination in the next defrost operation.

  Thereby, when it is determined that the difference A between the average value DRav of the operating rate for a certain period of the compressor 18 before the start of defrosting and the operating rate DR0 immediately after the previous defrosting is equal to or less than the predetermined lower limit value Amin. Since the defrosting end temperature Tde is lowered and it is possible to determine the end of the defrosting at the defrosting end temperature Tde lower than the initial defrosting end temperature Tde, the operation of the compressor 18 before the defrosting is started. When the difference A between the average value DRav of the rate and the operating rate DR0 immediately after the previous defrosting is small and there is no or little frosting on the evaporator 5, the removal is performed earlier than the normal defrosting operation. It is possible to end the frost operation. Accordingly, it is possible to reduce the influence of defrosting on the storage chamber 3, to further improve the cooling efficiency, and to further suppress the temperature rise of the stored articles. Become.

  On the contrary, the amount of frost formation on the evaporator 5 is large, and the difference A between the operation rate DRav during a certain period of the compressor 18 and the operation rate DR0 immediately after the previous defrosting is higher than a predetermined lower limit value Amin. In this case, since the end timing of the defrosting operation is determined based on the initial defrosting end temperature Tde, it is possible to smoothly perform the defrosting of the evaporator 5, efficient defrosting operation, and cooling Driving can be realized.

  Accordingly, the defrosting end temperature Tde of the evaporator 5 is corrected using the operation rate of the compressor 18 as an index, and the end timing of the defrosting operation is determined based on the defrosting end temperature Tde. Appropriate defrosting according to frost conditions can be realized.

  In the defrosting end temperature correction determination by the above determination methods, in step S5, the control device C excludes the operation rate when the opening / closing of the door 24 detected by the door opening / closing sensor 28 is a predetermined number or more from the determination. Therefore, after excluding changes in the operating rate of the compressor 18 due to frequent opening and closing of the door 24, the evaporator 5 can be defrosted using the operating rate of the compressor 18 as an index. It becomes possible. Thereby, it becomes possible to implement | achieve appropriate defrost according to the frost formation condition to the evaporator 5. FIG.

  In the present embodiment, the defrosting device is configured by the control device C as described above and the heater 26 as the defrosting means, but is not limited to this. For example, a high-temperature refrigerant is supplied to the evaporator 5. Means enabling so-called hot gas defrost to flow in (actually constituted by a refrigerant circuit 40 capable of changing the refrigerant flow path, a valve device, and a control means for controlling the valve device), the compressor 18 Means for enabling so-called off-cycle defrosting without supplying refrigerant to the evaporator 5 including stopping the operation (actually, the refrigerant circuit 40 to which the compressor 18 and the like are connected, and the compressor 18 and the blower 6 are operated. In addition to stopping the supply of the refrigerant to the evaporator 5, the defrosting control according to the present invention is performed even when the fan 6 for circulating in the warehouse is always operated. Can be executed.

It is a vertical side view of the cooling storehouse to which the present invention is applied. It is a vertical side view of a cooling storage. It is a refrigerant circuit figure of a cooling device. It is an electrical block diagram of a control apparatus. It is a flowchart figure of a defrost operation. It is a flowchart figure of defrost end temperature correction.

Explanation of symbols

R Cooling storage C Control device 2 Heat insulation box 3 Storage room (space to be cooled)
4 Cooling Device 5 Evaporator 6 Blower 18 Compressor 19 Condenser 20 Condenser Blower 24 Door 26 Heater (Defrosting Means)
27 Inside temperature sensor 28 Door open / close sensor (door open / close detection means)
40 Refrigerant circuit 42 Outside air temperature sensor (outside air temperature detecting means)
43 Memory (memory means)
44 Evaporator temperature sensor (defrosting end temperature detecting means)
45 timer (time limit means)

Claims (3)

In the cooling device that cools the space to be cooled by the cooling action of the evaporator that constitutes the refrigerant circuit together with the compressor, and melts and removes the frost attached to the evaporator by the defrosting means.
A defrosting end temperature detecting means for detecting a predetermined defrosting end temperature of the evaporator, and a control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means,
The control means starts defrosting of the evaporator by the defrosting means at a predetermined timing, ends defrosting when the temperature of the evaporator rises to the defrosting end temperature,
When it is determined that the operation rate of the compressor before the start of defrosting or the average value of the operation rate during a certain period is equal to or lower than a predetermined lower limit value, the defrosting end temperature is reduced. The defroster of the cooling device to be used. In the cooling device that cools the space to be cooled by the cooling action of the evaporator that constitutes the refrigerant circuit together with the compressor, and melts and removes the frost attached to the evaporator by the defrosting means.
A defrosting end temperature detecting means for detecting a predetermined defrosting end temperature of the evaporator, and a control means for controlling the defrosting means based on the output of the defrosting end temperature detecting means,
The control means starts defrosting of the evaporator by the defrosting means at a predetermined timing, ends defrosting when the temperature of the evaporator rises to the defrosting end temperature,
When it is determined that the difference between the operation rate of the compressor before the start of defrosting or the average value of the operation rate over a certain period and the operation rate immediately after the previous defrosting is equal to or less than a predetermined lower limit value The defrosting device for a cooling device, wherein the defrosting end temperature is lowered.   Door opening / closing detection means for detecting an opening / closing state of a door that closes the cooled space so as to be freely opened and closed, and the control means performs the operation when the opening / closing of the door detected by the door opening / closing detection means is a predetermined number of times or more. 3. The defrosting device for a cooling device according to claim 1, wherein the rate is excluded from the determination.

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