JP2011099628A - Cooling device and refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a cooling device in which a defrosting operation time is suppressed to a necessary minimum. <P>SOLUTION: The cooling device includes: an evaporator 3 for cooling an object to be cooled; a drain pan 6 that receives water generated in the evaporator 3 and exhausts it from an outlet 7; a temperature sensor 11 for detecting a water amount discharged from the drain pan 6; and a temperature determination control part 12 that performs determination treatment of a defrosting operation end based on a detection of the temperature sensor 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooling device that performs cooling. In particular, the present invention relates to the determination of the end of the defrosting operation for defrosting the device.

  For example, there is a cooling device that cools the target space by causing heat exchange between the air in the target space in a freezer, a refrigerator, and the like and a refrigerant. In the cooling device, in order to cool the ambient air of the device, in a heat exchanger that performs heat exchange (hereinbelow described as functioning as an evaporator), water in the air (water vapor) passes through a pipe and fins through which the refrigerant passes. It is condensed and cooled on the surface to form frost. Here, when the frost grows as the operation time elapses, the fins and the pipes cannot be brought into direct contact with air, and the heat exchange efficiency between the refrigerant and the air deteriorates. In addition, there is a problem that frost blocks between the fins, the air volume of the air sent in decreases, the refrigeration capacity decreases, and the operation efficiency deteriorates. For this reason, for example, a defrosting operation in which frost is periodically melted is performed by a method such as heating a heater attached to an evaporator or the like.

  Since this defrosting operation involves heating by a heater, energy consumption is large and there is a problem in terms of energy saving. In addition, cooling in the target space cannot be performed during the defrosting operation, so long-term removal is required. If the frost operation is performed, the temperature rises.

  Therefore, in the conventional cooling device, in order to appropriately determine the end of the defrosting operation, the detection of the pipe temperature at the evaporator inlet is generally started together with the start of the defrosting operation, and the temperature related to the detection exceeds the set value. In some cases, the defrosting operation is terminated (see, for example, Patent Document 1).

Japanese Patent Laying-Open No. 2008-304137 (FIG. 1)

  However, in the above method, the set value is set based on the temperature in the piping at the evaporator inlet. For this reason, when the set temperature of the space to be cooled is low, the piping at the inlet of the evaporator is cooled by air or the like, and the temperature related to detection sometimes differs greatly from the temperature in the actual evaporator. Therefore, even if the frost attached to the evaporator is completely melted, it takes time for the temperature related to detection to rise to the set value, delaying the end of the defrosting operation, and causing a problem of performing a useless defrosting operation. There was a possibility.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a cooling device in which the defrosting operation time is minimized.

  The cooling device according to the present invention includes a cooling means for cooling an object to be cooled, a drain pan that receives water generated in the cooling means and discharges it from a drain outlet, a detection means for detecting the amount of drainage from the drain pan, and a detection And a control means for performing a determination process of the completion of the defrosting operation based on the detection of the means.

  According to the present invention, based on the detection by the detection means, the control means determines the end of the drain water flow from the drain pan directly or indirectly, and determines the end of the defrosting operation. Can be done. For this reason, unnecessary heating and the like can be prevented and energy can be saved without continuing heating even after the frost has melted and drainage is completed.

It is the block diagram which looked at the cooling device in connection with Embodiment 1 of this invention from the suction side. It is sectional drawing which looked at the cooling device in connection with Embodiment 1 of this invention from the side surface. FIG. 6 is a configuration diagram showing a shape and the like of a drain pan 6. It is a figure showing the drain pan lower part installation position of a temperature sensor. It is the schematic diagram which showed the flow of the drain water during a defrost operation. It is a figure showing the drain pan temperature distribution according to temperature sensor position. It is a figure showing the drain pan temperature distribution in a defrost operation. It is a figure showing the flowchart of the control which the temperature determination control part 12 performs. It is a figure showing the time change of the temperature which concerns on the detection of the temperature sensor. It is a block diagram which shows the cooling device in Embodiment 2 of this invention. It is a figure showing the flowchart of the control which the flow velocity determination control part 14 performs. It is a block diagram which shows a float sensor installation position. 3 is a front view of a partition plate 18. FIG. It is a figure showing the flowchart of the control which the water level determination control part 18 performs. It is a figure which shows the structural example of the refrigerating-cycle apparatus which concerns on Embodiment 4. FIG.

Embodiment 1 FIG.
1 and 2 are diagrams schematically showing the configuration of the cooling device according to Embodiment 1 of the present invention. FIG. 1 is a view seen from the side of sucking air to be cooled, and FIG. 2 is a view showing a cross section of a side face. The cooling device includes, for example, a compressor that performs a compression stroke, a condenser having a blower that performs a condensation stroke, an expansion valve (throttle device) that performs an expansion stroke, and an evaporator that performs an evaporation stroke, and configures a refrigerant circuit. In the refrigeration cycle apparatus, the apparatus includes an evaporator.

  As shown in FIGS. 1 and 2, the cooling device includes an evaporator 3 having fins 2 for performing heat exchange between the refrigerant and the air to be cooled, and a fan 4 for blowing air driven by a motor or the like. Housed in the housing 1. In order to perform defrosting of the evaporator 3 periodically, the normal operation by the compressor is stopped and an electric heater (hereinafter referred to as a heat exchanger heater 5) attached to the evaporator 3 is energized.

  At this time, the frost adhering to the evaporator 3 is melted by the heat applied by the heat exchanger heater 5, and drops from the evaporator 3 as water droplets or sherbet-like ice (hereinafter referred to as drain water). To do. For this reason, a drain pan 6 serving as a tray is provided below the evaporator 3. The drain pan 6 receives the falling drain water and drains it out of the cooling device via the drain port 7 and the drain hose 8.

  FIG. 3 is a diagram showing the shape of the drain pan 6 and the like. The drain pan 6 is provided with a drain groove 10 so that drain water on the drain pan 6 is collected. In addition, the drain port 7 communicating with the drain groove 10 is inclined so that drain water flows (FIG. 3B). In order to prevent drain water from re-freezing on the drain pan 6, an electric heater 9 (hereinafter referred to as the drain pan heater 9) is also installed on the drain pan 6. With the shape as shown in FIG. 3 and the like, the drain water on the drain pan 6 is discharged from the drain outlet 7 through the drain groove 10 while being heated by the drain pan heater 9 so as not to freeze again. Further, a temperature sensor 11 is installed in the vicinity of the heating part of the drain pan heater 9 and below the drain groove 10 (in the vicinity of the drain port 7) to detect the temperature of the drain pan 6.

  The temperature determination control unit 12 performs a process of determining the end of the defrosting operation based on the temperature detected by the temperature sensor 11. In the present embodiment, the temperature determination control unit 12 is configured by, for example, a microcomputer. For example, the end of the defrosting operation is determined by performing processing based on a predetermined program stored. Moreover, the temperature determination control part 12 shall have storage means, such as a time measuring means, such as a timer, and a memory which memorize | stores data etc., in order to perform a process.

  In the cooling device configured as described above, when the defrosting operation is started and energization of the heat exchanger heater 5 is started, the heat generated by the heat exchanger heater 5 is absorbed, and after a while, frost attached to the evaporator 3 is formed. At the beginning of melting, drain water falls into the drain pan 6. As the amount of frost attached to the evaporator 3 decreases, the amount of drain water flowing out from the drain pan 6 gradually decreases, and finally does not flow. For this reason, it can be considered that the time when the drain water is finished is almost the same as the time when the defrosting is finished. Therefore, in the present embodiment, the temperature determination control unit 12 detects the temperature change of the drain pan 6 to indirectly detect the end of the drain water flow, and determines whether to end the defrosting operation.

  FIG. 4 is a diagram for explaining an installation location of the temperature sensor 11. Here, a difference in temperature change when the temperature sensor 11 is installed at four points (i), (ii), (iii), and (iv) on the drain pan 6 will be described.

  FIG. 5 is a diagram showing the positional relationship between the drain pan 6, the evaporator 3, and the fan 4. As shown in FIG. 5 (b), in the cooling device in the present embodiment, the evaporator 3 is arranged not on the entire upper portion of the drain pan 6 but on one side (on the upper side in FIG. 5 (a)). . A fan 4 is arranged at the upper part on the other side. Thus, if the evaporator 3 is not located in the whole upper part of the drain pan 6, at the time of a defrost operation, in the drain pan 6, the position used as the lower part of the evaporator 3 rather than the position used as the lower part of the fan 4 is located. A lot of drain water will drip and flow. In addition, after starting the defrosting operation, heat due to energization is transmitted radially from the position of the drain pan heater 9. From the above, the position of (i) is close to the position of the drain pan heater 9 and is a position where the heat of the drain pan heater 9 is sufficiently transmitted, and is near the drain outlet 7 at the lower part of the evaporator 3. It is in the position where drain water flows until the frost of 3 finishes melting.

  On the other hand, although the heat of the drain pan heater 9 is sufficiently transmitted at the position (ii), the amount of drain water flows is small because it is at the lower part of the fan 4. The position (iii) takes time for the heat of the drain pan heater 9 to be transmitted, and the amount of drain water is smaller than that of the drain water flowing to the position (i). Finally, at the position (iv), the heat of the drain pan heater 9 is difficult to be transmitted, and the drain water hardly flows.

  FIG. 6 is a diagram showing temperature change trends at four points on the drain pan 6 shown in FIG. In FIG. 6, the vertical axis represents temperature and the horizontal axis represents time. When energization of the heat exchanger 5 and the drain pan heater 9 is started at the start of the defrosting operation, the frost adhering to the evaporator 3 starts to be melted by the heat of the heat exchanger heater 5. For a while from the start of energization, the drain water from the evaporator 3 does not drip onto the drain pan 6, so the drain pan 6 is heated by the drain pan heater 9 and the temperature of the drain pan 6 rises with time. At this time, at the positions (i) and (ii) where the distance from the drain pan heater 9 is short, the temperature rises faster than the positions (iii) and (iv).

  Thereafter, the frost melted in the evaporator 3 is dripped onto the drain pan 6 as drain water and begins to flow toward the drain port 7. However, since the positions (i) and (iii) are at the lower part of the evaporator 3, the fan 4 The drain water flows more dripping than the positions (ii) and (iv) at the lower part of the water. For this reason, the heat transmitted from the drain pan heater 9 to the drain pan 6 tends to be less than the cooling heat by the drain water, and the temperature detected by the dripping of the drain water is lowered according to the temperature of the drain water. Furthermore, regarding the flow of drain water, (i) is located at (iii) and (ii) is downstream from (iv), so that drain water flows and collects from the upstream.

  From these facts, the presence or absence of drain water can be obtained by installing the temperature sensor 11 at a position as shown in (i) of FIG. 5 near the drain pan heater 9 where the drain water melted by the frost attached to the evaporator 3 flows. The temperature change of the drain pan 6 due to can be accurately detected.

FIG. 7 is a diagram showing a time transition during the defrosting operation of the temperature related to the detection of the temperature sensor 11 installed at the position (i) in FIG. 5. When energization of the drain pan heater 9 and the heat exchanger heater 5 is started at the start of the defrosting operation, the heat of the heat exchanger heater 5 starts to melt the frost adhering to the evaporator 3. Since drain water does not drip from the evaporator 3 for a while after the start of energization, the drain pan 6 is heated by the drain pan heater 9, so that the temperature associated with detection by the temperature sensor 11 gradually increases. Thereafter, the frost melted in the evaporator 3 melts and dripped onto the drain pan 6 as drain water and starts flowing toward the drain port 7. Then, as time elapses, the amount of drain water increases, and when the amount of heat transferred from the drain pan heater 9 to the drain pan 6 becomes less than the amount of heat absorbed by the drain pan heater 9 and the drain pan 6, the temperature of the drain pan 6 starts to decrease. The change point at which the temperature of the drain pan 6 is changed from rising to falling and the point A, the maximum temperature the temperature of the detection of the temperature sensor 11 at this time is T _A.

Thereafter, when the frost in the evaporator 3 is completely melted, the amount of drain water flowing is reduced, the amount of heat transmitted from the drain pan heater 9 to the drain pan 6> cooling heat by the drain water, and the drain pan temperature begins to rise again. The change point at which the temperature of the drain pan 6 is changed to increase from the lowered and point B, the temperature of the detection of the temperature sensor 11 at this time is the lowest temperature T _B.

When the amount of drain water further decreases and the temperature of the drain pan 6 continues to rise and reaches the set temperature (point C), the energization of the heat exchanger heater 5 and the drain pan heater 9 is terminated, and the normal cooling operation is resumed. . A temperature related to detection by the temperature sensor 11 at point C is set as a set temperature T _C.

  FIG. 8 is a diagram illustrating a flowchart of a process related to the determination of the completion of the defrosting operation performed by the temperature determination control unit 12. After starting the defrosting operation, energization of the heat exchanger heater 5 and the drain pan heater 9 is started, and based on a signal from the temperature sensor 11 installed in the drain pan 6, the temperature determination related to the detection of the temperature sensor 11 is performed at a predetermined interval. Start with.

Then, it is determined whether or not the temperature (pre-detection temperature) T _n-1 related to the previous detection by the temperature sensor 11 is _{equal to} or higher than the temperature (current detection temperature) T _n related to the current detection (S1). If it judges that it is above, pre-detection temperature _{Tn-1 is made} into temporary value _Tmax of the maximum temperature (S2). Further, the first predetermined time period (e.g., 5 minutes), if the temporary value T _max of the maximum temperature before the detection temperature T _n-1 or more (S3), a temporary value T _max of the maximum temperature shown in FIG. 7 A determining a maximum temperature T _A at point (S4).

Next, it is determined whether or not the current detection temperature T _n is _equal to or higher than the previous detection temperature T _n-1 (S5). If it is judged that it is above, pre-detection temperature _{Tn-1 is made} into temporary value _Tmin of the minimum temperature (S6). Further, the second predetermined time (e.g., 1 minute), if the detected temperature T _n-1 or less before the provisional value T _min of the minimum temperature (S7), the provisional value T _min of the lowest temperature, B shown in FIG. 7 determining the lowest temperature T _B at the point (S8).

Then, the set temperature T _C is calculated based on the formula (1) from the determined maximum temperature T _A and minimum temperature T _B and determined (S9). Here, X is a specified value as a coefficient. Since the specified value X varies depending on the size of the cooling device and the like, it is obtained in advance for each model, for example, in verification of each cooling device development test.
_{T C = X (T A -T} B) + T B ... (1)

FIG. 9 is a diagram illustrating a temporal change in temperature related to detection by the temperature sensor 11 attached to the drain pan 6 during the defrosting operation. FIG. 9 shows an actual machine verification result of the specified value X when the amount of frost formation is varied, taking a 5 horsepower device as an example. The horizontal axis represents time [min], and the vertical axis represents temperature [° C.]. FIG. 9 also shows the set temperature T _C obtained by substituting X = 0.7 into the equation (1), the time when the frost has actually melted and the drain water has finished flowing, and the evaporator 3 inlet piping. The defrosting end time by the attached temperature thermo (sensor) is also shown.

Regarding the specified value X, the smaller the value, the faster the defrosting operation ends. However, if it is too small, normal operation may start before the frost attached to the evaporator 3 is completely melted, before draining from the drain pan 6, etc., which may cause freezing and root ice. In FIG. 9, when the specified value X = 0.7, the drain pan temperature and the set temperature T _C at the time when the frost has melted and the drain water has finished flow are equal regardless of the frost formation amount of the evaporator 3. It can be seen that the temperature becomes. Therefore, the value of the specified value X in the expression (1) is not particularly limited, but about 0.7 (for example, between 0.68 and 0.72) can be set as one target. The actual machine verification shows that the end of frost melting can be determined more accurately than the end of defrosting determination by the temperature thermo attached to the inlet pipe of the evaporator 3.

To set the temperature T _C which was determined as described above, current and temperature of the current detection temperature T _n is, when judged that a set temperature T _C or higher (S10), the heat exchange heater 5 and drain pan heater 9 The determination based on the detection of the sensor 11 is terminated, and the defrosting operation is terminated (S11). Then, normal operation (cooling operation) is restored.

On the other hand, after starting the defrosting operation, if it is determined in S1 that the previous detection temperature T _n-1 is not _{equal to} or higher than the current detection temperature T _n (the current detection temperature T _n is higher), the time limit t _L has elapsed. And whether or not the current detection temperature T _n is _equal to or higher than the limit temperature T _L (S12). If it is determined that the current detection temperature T _n does not fall below the limit temperature T _L even after the limit time t _L has elapsed, it is determined that the evaporator 3 is not frosted, and the defrosting operation is terminated (S11). ) Return to normal operation. Here, the time limit t _L and the temperature limit T _L are determined by verification of each cooling device development test because the optimal time and temperature vary depending on the size of the cooling device and the like.

  As described above, in the cooling device according to the first embodiment, the amount of drain water discharged from the drain pan 6 is determined based on the temperature related to the detection of the temperature sensor 11 installed in the drain pan 6 by the temperature determination control unit 12. The determination of the end of the defrosting operation can be appropriately performed by indirectly determining. For this reason, unnecessary heating can be prevented without continuing heating even after the frost has melted and drainage is completed. In addition, since the temperature of the space to be cooled is not increased unnecessarily by stopping the normal operation due to the defrosting operation, heating the heat exchanger heater 5 and the drain pan heater 9, etc., for example, the freshness of the items in the warehouse can be maintained. I can do it. Moreover, the energy consumed for recooling can be reduced. From the above, a cooling device capable of saving energy can be obtained.

Moreover, since the temperature sensor 11 is installed in the vicinity of the drain pan heater 9 and the drain port 7 at a position where the temperature change related to the detection increases according to the amount of drainage from the drain port 7, the setting related to the determination of the end of the defrosting operation The accuracy of the temperature T _C can be increased. Then, based on the temperature according to the detection of the temperature sensor 11 from the defrosting operation starts, the first predetermined time, the temperature was maintained provisional value T _max of the maximum temperature and the maximum temperature T _A, the second predetermined time, determine the temperature maintained provisional value T _min of the minimum temperature as a lowest temperature T _B, as determined by calculation or the like set temperature T _C on the basis of the maximum temperature T _a and the minimum temperature T _B, the set temperature T _C Since it has been determined that the defrosting operation has ended when it reaches, it is possible to perform a more accurate determination than determining the completion of the defrosting operation based on the temperature of the evaporator 3 inlet pipe. Further, by making the temperature at which the maximum and minimum values can be maintained for a predetermined time as the maximum temperature and the minimum temperature, reliable determination can be performed.

Embodiment 2. FIG.
In the first embodiment, the temperature sensor 11 detects the temperature change of the drain pan 6 to indirectly detect the amount of drain water discharged from the drain pan 6 and determine the end of the defrosting operation. there were. Next, a cooling device that detects the flow rate of drain water and determines the end of the defrosting operation will be described as a second embodiment.

  FIG. 10 is a diagram schematically illustrating the configuration of the cooling device according to the second embodiment. In FIG. 10, devices and means having the same numbers as those in FIG. 1 perform the same operations as those described in the first embodiment. The drain pipe 15 is connected to the downstream side of the drain hose 8. In the present embodiment, the flow sensor 13 is installed in the drain pipe 15 through which the drain water discharged from the drain pan 6 flows, and the flow rate of the drain water discharged is detected. The installation position of the flow sensor 13 is not particularly limited. However, if the flow sensor 13 is installed in a channel closer to the drain port 7 in the channel after the drain port 7, the drainage state from the drain pan 6 can be detected earlier. So it is effective.

  The flow rate determination control unit 14 performs a process of determining the end of the defrosting operation based on the flow rate detected by the flow sensor 13. Similar to the temperature determination control unit 12 of the first embodiment, the flow rate determination control unit 14 is also configured by, for example, a microcomputer and performs processing based on a program. In addition, it has time measuring means such as a timer and storage means such as a memory for storing data.

FIG. 11 is a diagram illustrating a flowchart of processing relating to determination of the completion of the defrosting operation performed by the flow velocity determination control unit 14. When the defrosting operation is started, based on the signal from the flow sensor 13, the flow velocity V of the drain water related to the detection of the flow sensor 13 is determined. Since it takes time until the frost adhering to the evaporator 3 melts and the drain water falls, the drain water is not discharged from the discharge port 7 immediately after the start of the defrosting operation, so the flow velocity is V _n = 0 [m / s]. Thereafter, when the drain water falling on the drain pan 6 starts to flow, the flow rate of the drain water becomes V _n > 0 [m / s]. Therefore, based on the flow velocity relating to the detection by the flow sensor 13, it is determined whether or not the flow velocity of the drain water is V _n > 0 [m / s] (S2-1). Here, it is determined whether or not V _n > 0, but it may be determined whether or not the flow velocity V _n is faster than a first predetermined value (> 0).

If it is determined that the flow velocity becomes V _n > 0 [m / s], it is then determined again based on the detection of the flow sensor 13 whether the flow velocity V _n = 0 [m / s]. . (S2-2). This is because when the frost attached to the evaporator 3 is almost completely melted, the amount of drainage from the drainage port 7 is reduced, and the flow velocity finally becomes zero. Here, it is determined whether or not the flow velocity V = 0. However, for example, a second predetermined value (<first predetermined value) is determined, and it is determined whether or not the second predetermined value is reached. May be.

If it is determined that V _n = 0 [m / s], the cooling device is completely stopped (S2-3). Here, the total stop of the cooling device means, for example, stoppage of energization to the heat exchanger heater 5 and the drain pan heater 9, stop supply of hot gas, and the like (hereinafter the same).

Here, if it is determined that V _n = 0 and the cooling device is completely stopped and then the normal operation is started immediately, the drain water adhering to the evaporator 3 (fin 2) has not been dripped onto the drain pan 6 and finished. There is a risk that it will be allowed to cool and freeze again. Further, the drain water remaining in the drain pan 6 may become root ice. Then, it is made to wait until drainage time passes (S2-4), and drain water does not remain in the evaporator 3 and the drain pan 6. FIG. Since the draining time varies depending on the size of the cooling device (evaporator 3), for example, the draining time may be set in accordance with the size of the cooling device.

  When it is determined that the draining time has elapsed, the defrosting operation is terminated (S2-5). Then, normal operation (cooling operation) is restored.

  As described above, in the cooling device of the second embodiment, the flow rate determination control unit 14 determines the end of the defrosting operation based on the flow rate of the drain water according to the detection of the flow sensor 13 installed in the drain pan 6. Therefore, the flow of drain water discharged from the drain pan 6 can be determined directly. For this reason, the end of the defrosting operation can be appropriately determined, and unnecessary heating after the frost has melted can be prevented. In addition, it is possible to maintain the freshness of the product without unnecessarily increasing the internal temperature due to operation stop, heating, etc., and to reduce the energy used at the time of re-cooling, so that an energy saving effect can be obtained. . And since the state of the drain water in the drain pan 6 can be directly detected from the flow rate, and the end determination can be made only by the detected flow rate, the end can be performed regardless of the model of the refrigeration apparatus (size of the evaporator 3 and the like). The setting used as the judgment reference can be made the same.

Embodiment 3 FIG.
The cooling device of the second embodiment detects the flow rate of drain water and determines the end of the defrosting operation. Next, as a third embodiment, a cooling device that detects the displacement of the drain water amount by the float sensor 16 and determines the end of the defrosting operation will be described.

  FIG. 12 is a configuration diagram showing an installation position and the like of the float sensor 16 provided in the drain pan 6 according to the third embodiment. In the third embodiment, the same reference numerals as those in FIG. 1 and the like perform the same operations as those described in the first embodiment. In the present embodiment, a partition plate 18 is provided for temporarily collecting drain water collected at the drain port 7 and flowing.

  FIG. 13 is a view of the partition plate 18 as viewed from the front. The partition plate 18 is assumed to have a drain hole 18 </ b> A for finally allowing drain water to flow into the drain port 7. And as shown in FIG. 12, the float sensor 16 for detecting the water level of the drain water which blocked | interrupted by the partition plate 18 and was temporarily collected in the drain outlet 7 vicinity is installed.

  The water level determination control unit 17 performs processing for determining the end of the defrosting operation based on the water level detected by the float sensor 16. The water level determination control unit 17 is also composed of, for example, a microcomputer and performs processing based on a program. In addition, it has time measuring means such as a timer and storage means such as a memory for storing data.

FIG. 14 is a diagram illustrating a flowchart of processing related to determination of the completion of the defrosting operation performed by the water level determination control unit 17. After the start of the defrosting operation, the water level related to detection by the float sensor 16 is determined based on a signal from the float sensor 16 installed in the drain pan 6. Since it takes time until the frost attached to the evaporator 3 melts and the drain water falls, the drain water does not flow immediately after the start of the defrosting operation, and the water level H _n = 0 [m] in the drain water. Thereafter, when the drain water that has fallen on the drain pan 6 begins to flow, the water level H _n > 0 [m / s] in the drain water is obtained. Therefore, it is determined whether or not the float sensor 16 has reached the water level H _n > 0 [m / s] in the drain water (S3-1). Here, a predetermined value instead of 0 may be determined.

If it is determined that the water level H _n > 0 [m] in the drain water, then it is determined again based on the detection of the flow sensor 13 whether or not the water level H _n in the drain water is 0 [m]. To do. (S3-2). This is because when the frost attached to the evaporator 3 is almost completely melted, the amount of drain water flowing into the drain port 7 is reduced. On the other hand, since drain water flows from the drain hole 18A, the drain port finally This is because the water level of drain water collected in the vicinity of 7 becomes zero.

  If it is determined that the water level Hn = 0 [m], the cooling device is completely stopped (S3-3). As in the case of the second embodiment, if the normal operation is started immediately, the drain water adhering to the evaporator 3 (fin 2) or the like may be frozen, so that it is kept on standby until the draining time elapses. (S3-4).

  If it is determined that the draining time has elapsed, the defrosting operation is terminated (S25). Then, normal operation (cooling operation) is restored.

  As described above, in the cooling device of the third embodiment, the water level determination control unit 17 determines the end of the defrosting operation based on the water level of the drain water according to the detection of the float sensor 16 installed in the drain pan 6. Therefore, the flow of drain water discharged from the drain pan 6 can be determined directly. For this reason, the end of the defrosting operation can be appropriately determined, and unnecessary heating after the frost has melted can be prevented. In addition, it is possible to maintain the freshness of the product without unnecessarily increasing the internal temperature due to operation stop, heating, etc., and to reduce the energy used at the time of re-cooling, so that an energy saving effect can be obtained. . And since the state of the drain water in the drain pan 6 can be directly detected from the water level and the end determination can be performed only by the detected water level, the same setting as the reference for the end determination can be made regardless of the model of the refrigeration apparatus. I can do it.

Embodiment 4 FIG.
FIG. 15 is a diagram illustrating a configuration example of a refrigeration cycle apparatus according to Embodiment 4 of the present invention. A basic configuration of the refrigerant circuit configured by the refrigeration cycle apparatus will be described based on FIG. This refrigeration cycle apparatus performs cooling, refrigeration, etc. by utilizing the circulation of refrigerant.

  The refrigeration cycle apparatus includes a compressor 100, a condenser 200, an expansion device 400, and an evaporator 3 that are sequentially connected by a refrigerant pipe. Here, the compressor 100 and the condenser 200 are incorporated in an outdoor unit (heat source side unit) provided outside the target space for cooling, air conditioning, etc., and the expansion device 400 and the evaporator 3 are located in the target space. It is assumed that it is built in the cooling device (load-side unit) provided in.

  The refrigerant pipe includes a gas side refrigerant pipe through which a refrigerant that has turned into gas flows and a liquid side refrigerant pipe through which a refrigerant that has become liquid flows. For example, the refrigerant that has become liquid (including gas-liquid two-phase) by condensation in the condenser 200 passes through the liquid-side refrigerant pipe. Moreover, the refrigerant | coolant which became gas by evaporation in the evaporator 3, for example passes the gas side refrigerant | coolant piping. A blower (not shown) such as a fan is provided near the condenser 200 to send air outside the space to be cooled (hereinafter referred to as “outside air”) to the condenser 200 and promote heat exchange. . In the vicinity of the evaporator 3, the above-described fan 4 is provided.

  The compressor 100 draws in the refrigerant, compresses the refrigerant, makes it into a high-temperature and high-pressure gas state, and flows it through the refrigerant pipe. The condenser 200 is a heat exchanger that performs heat exchange between the refrigerant and the outside air to condense and liquefy the refrigerant. The expansion device 400 is generally composed of an expansion valve such as a pressure reducing valve or an electronic expansion valve, and expands the refrigerant by decompressing it. The evaporator 3 in the present embodiment has the cooling device described in the first to third embodiments. By the heat exchange between the refrigerant and air, the refrigerant is evaporated and vaporized.

  For example, the control means 500 composed of a microcomputer or the like controls the drive frequency of the compressor 100, the opening of the expansion device 400, and the like. Although not particularly limited, in the first to third embodiments described above, the control unit 500 may perform the processing performed by the temperature determination control unit 12, the flow velocity determination control unit 14, and the water level determination control unit 17. Further, although described as one control unit 500, for example, control units may be provided in the outdoor unit and the cooling device, respectively, and each control unit may control devices (means) included in each unit. At this time, control may be performed in cooperation so that signal communication is possible.

  Here, the refrigerant used for the refrigeration cycle apparatus will be described. Examples of the refrigerant that can be used in the refrigeration cycle apparatus include a non-azeotropic refrigerant mixture, a pseudo-azeotropic refrigerant mixture, and a single refrigerant. Non-azeotropic refrigerant mixture includes R407C (R32 / R125 / R134a) which is an HFC (hydrofluorocarbon) refrigerant. Since this non-azeotropic refrigerant mixture is a mixture of refrigerants having different boiling points, it has a characteristic that the composition ratio of the liquid-phase refrigerant and the gas-phase refrigerant is different. The pseudo azeotropic refrigerant mixture includes R410A (R32 / R125) and R404A (R125 / R143a / R134a) which are HFC refrigerants.

  The single refrigerant includes R22, which is an HCFC (hydrochlorofluorocarbon) refrigerant, R134a, which is an HFC refrigerant, and the like. Since this single refrigerant is not a mixture, it has the property of being easy to handle. In addition, natural refrigerants such as carbon dioxide, propane, isobutane, and ammonia can be used. R22 represents chlorodifluoromethane, R32 represents difluoromethane, R125 represents pentafluoroethane, R134a represents 1,1,1,2-tetrafluoroethane, and R143a represents 1,1,1-trifluoroethane. ing. Therefore, it is good to use the refrigerant | coolant according to the use and purpose of the refrigerating cycle apparatus.

  Next, the operation of the refrigeration cycle apparatus will be described. The high-temperature and high-pressure refrigerant compressed by the compressor 100 condenses and liquefies while dissipating heat by heat exchange with the outside air in the condenser 200 to become a liquid refrigerant. This liquid refrigerant flows into the expansion device 400, where it is depressurized and flows into the evaporator 3, for example, as a low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is all evaporated and gasified by heat exchange in the evaporator 3, becomes a gaseous refrigerant, and is sucked again into the compressor 100 and discharged.

  Even in the refrigeration cycle apparatus of the fourth embodiment configured as described above, it is possible to prevent unnecessary heating and the like after the defrosting operation described in the first to third embodiments, and to achieve energy saving. I can do it.

  In the embodiment described above, application to a refrigeration apparatus and an air conditioner has been described. The present invention is not limited to these devices, and can be applied to other refrigeration cycle devices having a refrigerant circuit and having an evaporator, such as a heat pump device.

  1 casing, 2 fins, 3 evaporators, 4 fans, 5 heat exchanger, 6 drain pan, 7 drain port, 8 drain hose, 9 drain pan heater, 10 drain groove, 11 temperature sensor, 12 temperature judgment control unit, 13 flow Sensor, 14 Flow rate determination control unit, 15 Drain pipe, 16 Float sensor, 17 Water level determination control unit, 18 Partition plate, 18A Drain hole, 100 Compressor, 200 Condenser, 400 Throttle device, 500 Control means.

Claims (6)

A cooling means for cooling the object to be cooled;
A drain pan that receives water generated in the cooling means and discharges it from a drain;
Detection means for detecting the amount of drainage from the drain pan;
A cooling device comprising: control means for performing determination processing for the completion of the defrosting operation based on detection by the detection means. Heating means for heating the drain pan (near the drain),
As the detection means, a temperature sensor is installed at a position close to the drain port and the heating means,
The cooling device according to claim 1, wherein the control means performs a defrosting operation end determination process based on a temperature related to detection by the temperature sensor.   The control means determines, as a maximum temperature value, a temperature value that maintains a maximum for a first predetermined time based on a temperature related to detection of the temperature sensor from the start of the defrosting operation, and further, a second predetermined value When the temperature value at which the time and the minimum are maintained is determined as the minimum temperature value, and it is determined that the set temperature value determined from the maximum temperature value and the minimum temperature value has been reached, a process for determining the end of the defrosting operation is performed. The cooling device according to claim 2. As the detection means, a flow rate sensor for detecting the flow rate of water discharged from the drain port is provided,
The cooling device according to claim 1, wherein the control unit performs a defrosting operation end determination process based on a flow rate according to detection by the flow rate sensor. As the detection means, a water level sensor for detecting the water level discharged from the drain outlet is provided,
The cooling device according to claim 1, wherein the control means performs a defrosting operation end determination process based on a water level related to detection by the water level sensor. A pipe connecting a compressor for compressing the refrigerant, a condenser for condensing the refrigerant by heat exchange, an expansion means for decompressing the condensed refrigerant, and an evaporator for evaporating the decompressed refrigerant by heat exchange A refrigeration cycle apparatus constituting a refrigerant circuit for circulating the refrigerant,
The said evaporator is a cooling means of the cooling device in any one of Claims 1-5, The refrigerating-cycle apparatus characterized by the above-mentioned.

Images