JP4435226B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a low-temperature apparatus such as a showcase, and particularly relates to defrosting of frost adhering to a heat exchanger used therein.

  In the conventional refrigeration apparatus, defrosting is started by an external timer signal set at regular intervals such as 6 hours or 12 hours.

  In addition, the conventional refrigeration apparatus performs the defrosting operation using at least one of the measurement value of the suction temperature measurement means, the blowout temperature measurement means, the suction temperature measurement means, and the blowout temperature measurement means of the heat exchanger. Control means for determining the start (see, for example, Patent Document 1).

  Further, the conventional refrigeration apparatus starts defrosting by either an internal timer or an external defrost signal, and when the defrost signal is input from the outside, the output of the subsequent defrost signal is In some cases, the defrosting signal from the internal timer is ignored and only the defrosting signal from the outside is used, and the defrosting is terminated depending on the defrosting termination condition of either the internal temperature or the defrosting elapsed time ( For example, see Patent Document 2).

JP 2006-183987 A (FIGS. 1 and 2) Japanese Patent No. 3045384 (FIGS. 1 and 2)

  The conventional refrigeration system does not detect a decrease in cooling capacity or the amount of frost, and starts a defrosting operation at regular intervals. There was a problem that the defrosting operation was entered in a state where the amount of frost formation was small and the cooling capacity was not lowered, and wasted energy was input.

  Also, heat exchangers have different frosting methods depending on the load condition, such as when there is a lot of frost formation at the center of the air passage or when there is a large amount of frost formation on the leeward side of the air passage. Therefore, it is difficult to grasp the decrease in cooling capacity with the same algorithm for refrigeration apparatuses with various storage temperature zones and types.

  In supermarkets and the like, the load conditions of refrigeration equipment such as showcases differ between daytime and nighttime, and the frosting rate on the heat exchanger varies depending on the load. If the start of defrosting is not determined according to the detected value at that time, there is a problem that appropriate defrosting is not performed.

  In addition, when one showcase enters a defrosting operation and the other performs a cooling operation in adjacent showcases, there is a problem that heat may enter through walls and wasteful energy may be used. There was a point.

  The present invention has been made to solve the above-described problems, and detects a decrease in the cooling amount or frost formation amount of the heat exchanger in the refrigeration apparatus, and determines whether or not to start defrosting based on the detected amount. The main purpose is to obtain a refrigeration apparatus that avoids useless energy input and saves energy by optimizing the defrosting start timing.

  In addition, another object of the present invention is to obtain a refrigeration apparatus that can ascertain a decrease in cooling capacity with the same general-purpose algorithm for refrigeration apparatuses with various storage temperature zones and types, and that can save energy.

  In addition, a defrosting start is determined in consideration of the grouping of adjacent refrigeration systems, and the same group of showcases starts defrosting at the same time. It is also aimed to obtain.

The refrigeration apparatus according to the present invention includes a heat exchanger, cooling operation means for supplying cold heat to the heat exchanger, defrosting operation means for defrosting frost adhering to the heat exchanger, and the cooling operation in the cooling operation. Cooling capacity estimating means for estimating the cooling capacity of the heat exchanger or a decrease in cooling capacity, and defrost permission means for permitting the start of operation of the defrosting operation means based on the estimation result of the cooling capacity estimating means The defrosting operation means is a refrigeration apparatus that defrosts the heat exchanger in synchronization with a defrosting execution signal from inside or outside the apparatus when the defrosting permission means permits the operation start. There,
The cooling capacity estimation means uses a plurality of feature quantities representing the cooling capacity of the heat exchanger, each limit value set for each of the plurality of feature quantities and each predictive value before reaching each limit value, and Comparison is made with the limit value and the predictive value corresponding to each of a plurality of feature amounts, and estimation is performed based on the comparison result.

The refrigeration apparatus according to the present invention includes a heat exchanger, cooling operation means for supplying cold heat to the heat exchanger, defrosting operation means for defrosting frost adhering to the heat exchanger, and the cooling operation. Cooling capacity estimation means for estimating the cooling capacity of the heat exchanger or a decrease in cooling capacity in the heat exchanger, and defrost permission means for permitting the start of operation of the defrosting operation means based on the estimation result of the cooling capacity estimation means And the defrosting operation means performs defrosting of the heat exchanger even if a defrosting execution signal from inside or outside of the apparatus is input when the defrosting permission means does not permit the operation start. It is a refrigeration apparatus that extends the defrost start until the next defrost timing,
The cooling capacity estimation means uses a plurality of feature quantities representing the cooling capacity of the heat exchanger, each limit value set for each of the plurality of feature quantities and each predictive value before reaching each limit value, and Comparison is made with the limit value and the predictive value corresponding to each of a plurality of feature amounts, and estimation is performed based on the comparison result.

  The refrigeration apparatus of the present invention prevents a state in which the prescribed performance cannot be exhibited due to an excessive amount of frost formation on the heat exchanger, and puts wasteful energy into defrosting with an excessively small amount of frost formation. The energy can be saved by starting defrosting with an appropriate amount of frost formation.

  In addition, the refrigeration system of the present invention can be defrosted apart between a plurality of installed showcases to prevent useless energy from being input, thereby saving energy.

Embodiment 1 FIG.
The configuration of the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram showing a state in which the refrigeration apparatus of Embodiment 1 is installed in a store such as a convenience store or a supermarket. In FIG. 1, a plurality of refrigerated or frozen showcases 13 are arranged in a store 14, and these refrigerated or frozen showcases 13 are connected to a refrigerated or frozen refrigerator 11 for food and beverages. Are refrigerated or frozen at all times. Therefore, the refrigerator 11 for refrigeration or freezing, the showcase 13 for refrigeration or freezing, and the refrigerant circuit which connects them comprise the refrigeration apparatus.
On the other hand, an air conditioner indoor unit 12 is arranged in the store 14 separately from this, and the air conditioner indoor unit 12 is connected to the air conditioner outdoor unit 10 to cool or heat the room according to the outside air temperature. Therefore, the outdoor unit 10 for air conditioning, the indoor unit 12 for air conditioning, and the refrigerant circuit which connects them comprise the air conditioner.

  FIG. 2 is a refrigerant circuit diagram of the refrigeration apparatus according to Embodiment 1 of the present invention. In FIG. 2, the refrigeration apparatus according to Embodiment 1 of the present invention has a refrigeration or refrigeration refrigerator 11 as an outdoor unit, and a refrigeration or refrigeration showcase 13 as an indoor unit. The refrigerator 11 for refrigeration or freezing includes a compressor 21, an outdoor heat exchanger 22, a fan 23 for an outdoor heat exchanger, a liquid reservoir 24 for accumulating excess refrigerant, and the like. Further, a showcase 13 for refrigeration or freezing (also simply referred to as showcase 13), an opening / closing valve 25 such as an electromagnetic valve, an expansion means 26 such as an expansion valve, a showcase heat exchanger 27, a fan 28 for a showcase heat exchanger, and the like. It has. The refrigerant circuit diagram excluding the showcase heat exchanger 27 and the showcase heat exchanger fan 28 functions as a cooling operation means for supplying cold heat to the showcase heat exchanger 27.

  Next, an outline operation of the refrigeration apparatus of the present invention will be described. The refrigerant compressed to high temperature and high pressure by the compressor 21 is condensed in the outdoor heat exchanger 22 by the action of the outdoor heat exchanger fan 23, and then discharged from the refrigerator 11 through a liquid reservoir 24 for storing excess refrigerant. Flow into the showcase 13. The refrigerant that has entered the showcase 13 passes through the on-off valve 25 and is expanded by the expansion means 26 to become low-temperature and low-pressure refrigerant. After being evaporated by the operation of the showcase fan 28 in the showcase heat exchanger 27, The case 13 exits and returns to the compressor 21 of the refrigerator 11 again.

  When the showcase 13 is for refrigeration, the air temperature inside the showcase is about 0 ° C. and the evaporation temperature of the refrigerant is about −10 ° C. Further, when the showcase 13 is for freezing, the air temperature inside the showcase is about −18 ° C., and the evaporation temperature of the refrigerant is about −30 ° C. Regardless of whether the showcase is refrigerated or frozen, the surface temperature of the evaporator, that is, the piping and fins of the showcase heat exchanger 27 is 0 ° C. or lower, and is lower than the ambient air temperature. Water vapor in the air accumulates as frost around the showcase heat exchanger 27, that is, frosts. In the refrigerated showcase, when the ambient air around the showcase heat exchanger 27 is 0 ° C. or higher, water vapor in the air condenses as water droplets on the showcase heat exchanger 27 and then solidifies to form frost. On the other hand, in the refrigeration showcase, since the ambient air around the showcase heat exchanger 27 is 0 ° C. or lower, water vapor in the air sublimates and accumulates directly as frost around the showcase heat exchanger 27.

Thus, although the process leading to frosting differs between the refrigerated showcase and the freezing showcase, in any case, the frosting on the heat exchanger hinders heat exchange between the refrigerant and the air. If the amount of frost formation increases and the heat exchange performance is drastically reduced, the specified cooling capacity cannot be maintained, and the temperature inside the showcase rises. If the temperature inside the showcase rises, there is a problem in terms of maintaining the quality of the food, so the showcase is provided with defrosting means. Normally, when the showcase is operated for a certain period of time, frost is removed by the defrosting means. The timer is set to perform the defrosting operation to melt.
As the defrosting means, a heater is generally used. In addition, an off-cycle defrost that stops the flow of the refrigerant until the frost is melted by the on-off valve 25, or a high-temperature and high-pressure refrigerant on the outlet side of the compressor 21 is used. In some cases, hot gas defrost introduced into the showcase heat exchanger 27 is used.

FIG. 3 is an internal configuration diagram of the showcase 13 of the refrigeration apparatus according to Embodiment 1 of the present invention. As shown in FIG. 3, a showcase heat exchanger intake air temperature sensor 31 (also simply referred to as an intake air temperature sensor 31) is provided on the windward side of the showcase heat exchanger 27. A heater 40 as a defrosting operation unit (or a defrosting unit) is provided on the upper side and the side surface. The heater 40 is for heating the air flowing into the showcase heat exchanger 27 and melting frost adhering to the heat exchanger 27. A driving signal for the heater 40 is transmitted from a timer built in the showcase 13 or a timer 41 installed outside.
The timer 41 can set the operation interval (defrosting interval) of the heater 40. The timer 41 and the heater 40 are connected to an in-showcase control board 42 built in the showcase 13, and when a defrost signal (defrost execution signal) is input from the timer 41 to the control board 42, the inside of the showcase The control board 42 closes the on-off valve 25, closes the refrigerant flow path, operates the heater 40, and starts the defrosting operation.
The defrosting operation is terminated when the detected temperature of the showcase heat exchanger blown air temperature sensor 32 (also simply called the blown air temperature sensor 32, here, two of 32A and 32B are installed) exceeds a specified value. Then, the normal cooling operation is resumed. One or a plurality of blown air temperature sensors 32 are provided. When a plurality of blown air temperature sensors 32 are installed, the completion is performed when the average value or the minimum value of the detected temperatures by the blown air temperature sensors 32 exceeds a specified value. Even if the defrosting operation is completed by using the refrigerant pipe temperature by the showcase heat exchanger refrigerant inlet temperature sensor 30 (also simply referred to as the refrigerant inlet temperature sensor 30) or the like instead of the temperature detected by the blown air temperature sensor 32. Good. Further, the defrosting operation may be terminated when a certain time has elapsed.
3, what is indicated by reference numeral 43 is a device that functions as a cooling capacity or frost amount estimation means and a defrost permission means of the showcase heat exchanger 27 provided in the refrigeration apparatus of the present embodiment. Here, it is composed of a microcomputer. The microcomputer 43 is connected to the various temperature sensors 30, 31, 32, etc., and estimates the cooling capacity or the amount of frost formation of the showcase heat exchanger 27 as shown in FIGS. Based on the estimation result, it is programmed to issue a defrost permission signal that the operation of the heater 40 may be started. Note that this cooling capacity or frost amount estimation / defrosting permission means may be provided separately from the showcase 13. In addition, the cooling capacity or frost amount estimation means and the defrost permission means may be configured from separate devices.
Further, the defrosting operation means is not limited to the heater 40 and may be anything as long as it can melt the frost adhering to the heat exchanger. It may be exhaust heat. In addition, if the refrigerant in the refrigeration cycle can be circulated in the reverse direction without providing any special items, the refrigerant can be heated by the exhaust heat of the compressor, etc., and frost can be melted. Can be played.

  Although the normal defrosting operation is performed as described above, the frosting amount of each showcase heat exchanger 27 is equal to the temperature and humidity of the air in the store 14 and the showcase 13 even if the cooling operation time is the same. The amount of frosting in each showcase always reaches its limit at the start of defrosting because it varies depending on the food load inside, the temperature of the outside air where the refrigerator 11 is installed, the capacity ratio of the refrigerator 11 and the showcase 13, etc. Not necessarily. During the defrosting operation, the power of the heater 40 is consumed, and at the end of the defrosting, it is necessary to cool the showcase 13 again. Therefore, the smaller the number of defrosting operations per day, the more energy is saved. Moreover, since defrosting raises the internal temperature of the showcase 13, it is not so desirable in terms of food quality, and it is desirable that the number of times of defrosting is small. However, if the amount of frost formation on the showcase heat exchanger 27 becomes too large, the heat exchange performance of the heat exchanger 27 is lowered and the prescribed cooling capacity cannot be maintained, and the internal temperature of the showcase 13 rises. End up. Therefore, it is desirable to start defrosting when the frost amount of the showcase heat exchanger 27 is not too much and is in an appropriate frost amount state. For that purpose, an increase in the amount of frost formation in the showcase heat exchanger 27 or a decrease in the cooling capacity accompanying the increase in the amount of frost formation is estimated (including detection and detection), and the defrosting is controlled based on that. Is desirable.

  Next, the detection method of the cooling capacity fall accompanying the increase in the amount of frost formation of a heat exchanger and the increase in the amount of frost formation is demonstrated. When the frosting amount of the showcase heat exchanger 27 is sufficiently increased, the cross-sectional area through which the air in the heat exchanger 27 flows decreases, so that the pressure loss when the air passes through the heat exchanger 27 increases. However, the amount of air that the fan 28 can send out decreases due to the characteristics of the showcase heat exchanger fan 28, and the wind speed of the air passing through the showcase heat exchanger 27 decreases. When the air velocity decreases, the time for heat exchange between the refrigerant flowing in the showcase heat exchanger 27 and the air increases, so that the blown air temperature detected by the blown air temperature sensor 32 as shown in FIG. Decreases toward the refrigerant evaporation temperature. The refrigerant evaporating temperature is substantially equal to the detected value of the refrigerant inlet temperature sensor 30 unless the pressure loss of the refrigerant in the pipe is very large. Further, since the heat load in the cabinet of the showcase 13 does not change, the intake air temperature detected by the intake air temperature sensor 31 rises due to a decrease in the amount of air sent from the showcase heat exchanger fan 28. Therefore, when the frost amount of the showcase heat exchanger 27 is sufficiently increased, the temperature difference between the intake air temperature and the blown air temperature of the heat exchanger 27 is larger than when the frost amount is small ((1)). formula).

  Heat exchanger intake air temperature-heat exchanger blown air temperature → increase (1)

Further, the temperature difference between the intake air temperature and the blown air temperature of the showcase heat exchanger 27 becomes large. However, depending on the type of the case, the evaporating temperature may be increased unless frost formation increases considerably due to the characteristics of the heat exchanger 27. Almost no change occurs, and the temperature efficiency, which is a value obtained by dividing the temperature difference between the intake air temperature and the blown air temperature by the temperature difference between the intake air temperature and the refrigerant evaporation temperature, increases (formula (2-A)). Generally, the temperature efficiency increases as the wind speed decreases.
Conversely, depending on the case, the evaporation temperature may decrease with frost formation, and the temperature efficiency may decrease. In this case, the reciprocal of temperature efficiency (formula (2-B)) increases. It is necessary to select the temperature efficiency or the inverse of the temperature efficiency according to the characteristics of the device.

Temperature efficiency = (heat exchanger suction air temperature−heat exchanger blown air temperature) / (heat exchanger suction
Air temperature-refrigerant evaporating temperature of heat exchanger)
≒ (heat exchanger suction air temperature-heat exchanger blown air temperature) / (heat exchanger suction
Air temperature-Heat exchanger refrigerant inlet temperature) → Increase (2-A)
1 / temperature efficiency = (suction air temperature of heat exchanger−refrigerant evaporation temperature of heat exchanger) / (of heat exchanger
(Intake air temperature-Heat exchanger air temperature)
≒ (heat exchanger intake air temperature-heat exchanger refrigerant inlet temperature) / (heat exchanger
(Intake air temperature-Heat exchanger air temperature) → Increase (2-B)

  Moreover, the internal temperature of the showcase 13 is given as an average temperature of the intake air temperature and the blown air temperature (equation (3)). Actually, the temperature of the blown air in the cabinet, which is the tip of the air path, should be used instead of the temperature of the blown air of the showcase heat exchanger 27.

Inside temperature = (suction air temperature of heat exchanger + outside air temperature inside the cabinet) / 2
≒ (Intake air temperature of heat exchanger + Outlet air temperature of heat exchanger) / 2 (3)

  In an open showcase that does not have a door at the product outlet, the blowout air and the air around the showcase are exchanged to some extent, which occupies most of the cooling load of the showcase. In order to reduce this change, the air curtain is made by the blowing air. However, as the frosting on the showcase heat exchanger 27 proceeds and the wind speed decreases, the wind speed of the air curtain also decreases. The rate of replacement with air increases, and the intake air temperature and the internal temperature rise. Since the showcase 13 is controlled to keep the inside temperature constant, when the inside temperature rises, the time during which the on-off valve 25 is open is increased and the inside temperature is lowered. Therefore, the inside temperature does not rise even if the intake air temperature rises until the frosting is considerably advanced. However, if the amount of frost formation further proceeds, it becomes impossible to control and the internal temperature rises (equation (4)).

   Inside temperature → rise (4)

In addition, the following (5-A) type | formula which replaced the suction air temperature of the denominator with the internal temperature may be used for the previous (2-A) type | formula.
Temperature efficiency = (heat exchanger intake air temperature-heat exchanger blown air temperature) / (compartment temperature-heat exchanger refrigerant inlet temperature) → increase (5-A)
The previous formula (2-B) may be the following formula (5-B) in which the intake air temperature of the molecule is replaced with the internal temperature.
1 / Temperature efficiency = (Internal temperature-Refrigerant inlet temperature of heat exchanger) / (Intake air temperature of heat exchanger-Outlet air temperature of heat exchanger) → Increase (5-B)

  Further, as described above, when frosting progresses, the intake air temperature rises and the temperature difference between the intake air temperature and the refrigerant evaporation temperature also increases (equation (6)).

  Intake air temperature of heat exchanger-Evaporation temperature of heat exchanger → Increase (6)

Similarly, the temperature difference between the internal temperature and the refrigerant evaporation temperature also increases as frost increases (formula (7)).
Internal temperature-refrigerant evaporating temperature of heat exchanger → increase (7)
Therefore, the sum of the expressions (6) and (7) also increases (expression (8)).

  (Intake air temperature of heat exchanger−refrigerant evaporation temperature of heat exchanger) + (inside temperature−refrigerant evaporation temperature of heat exchanger) → increase (8)

  That is, when the amount of frost formation on the showcase heat exchanger 27 increases, a change occurs in the plurality of feature amounts shown so far. Therefore, instead of looking at only one of these feature amounts, for example, by observing changes in a plurality of feature amounts such as Equation (1), Equation (2), Equation (4), and Equation (8). It becomes possible to capture the increase in the amount of frost formation more accurately.

  In addition, as shown in FIG. 3, when a plurality of blown air temperature sensors are installed like 32A, 32B, and 33, the average value of all of these or a plurality of sensors extracted from these is used as the blown air. It may be used as a temperature, or one of these may be used as a blown air temperature.

  By the way, in the supermarket, from morning to night, for example, 9:00 to 22:00 may be business hours, and the rest may be outside business hours. The business hours are time periods in which customers select and purchase products. If the defrosting operation is performed during this time period, the internal temperature rises. Although the temperature of the product itself does not increase much due to the defrosting operation, it is not good for the store image that the temperature inside the store is raised, and in some cases, condensation may occur on the product before it cools down again Yes, it is desirable to perform the defrosting operation outside business hours as much as possible. Therefore, conventionally, it has been set to be controlled by a timer so that the defrosting operation is performed outside the business hours or during a time zone when there are relatively few customers or products.

  Therefore, even if the increase in the amount of frost applied to the showcase heat exchanger 27 is detected by the feature amount as described above and the time when the defrost operation should be performed can be detected, the defrost operation is not performed immediately. As before, the defrosting operation should be performed outside the business hours or during a time when there are relatively few customers or products, and the defrosting operation synchronized with the defrosting execution signal from the timer or equivalent means is not required. I need it.

  However, in the method of performing the defrosting operation only by the conventional timer, the defrosting operation is entered even in a state where the amount of frost formation is small and the defrosting is not necessary, and energy is often wasted. Therefore, the method described above detects an increase in temperature efficiency due to an increase in the amount of frost formation, an increase in the internal temperature due to a decrease in cooling capacity, etc., and synchronizes with the timer when defrosting is necessary. It is desirable to perform a defrosting operation.

  On the other hand, if the amount of frost formation increases too much, the cooling capacity may not be maintained until the next defrosting timing by the timer. Accordingly, it is important to detect an increase in the amount of frost on the showcase heat exchanger 27 at an early stage.

Therefore, here, in order to detect the amount of frost on the showcase heat exchanger 27 at an early stage, a plurality of feature amounts as described above are used, and two different determination rule rules are used for these feature amounts. Make a decision at. In the present embodiment, two concepts of “limit value” and “predictive value” are used for this determination rule rule.
Each feature amount is not a constant value during operation, and always varies even if the amount of frost formation is small. Therefore, in order to accurately detect a decrease in the amount of frost formation or the cooling capacity, it is necessary to set a large threshold value for each feature amount. However, if it is set too large, the cooling capacity cannot be maintained until the next defrosting timing. Therefore, a boundary value at which such cooling capacity cannot be maintained or a value in the vicinity thereof is set and used as a limit value. On the other hand, in order to detect a decrease in the amount of frost formation or the cooling capacity as early as possible, it is necessary to make the threshold value of each feature amount as small as possible. However, if the value is too small, the threshold value enters the normal fluctuation range, and erroneous detection is likely to occur. Therefore, a predictive value, which is a value before reaching the limit value, that is, a value smaller than the limit value and sufficiently deviates from the normal fluctuation range and does not cause false detection is also set and used.
For example, when the three feature amounts of the feature amount 1, the feature amount 2, and the feature amount 3 are used, the start of the defrosting operation is determined based on the following rule rule, for example.

Feature value 1> limit value 1 or feature value 2> limit value 2 or feature value 3> limit value 3 starts defrosting operation (9)
Feature value 1> Sign value 1 and Feature value 2> Sign value 2 and Feature value 3> Sign value 3 starts defrosting operation (10)

The limit value and the sign value are values set for each feature amount, and are set as follows here.
Predictive value = α × (maximum feature value−average feature value) + average feature value (11)
Limit value = β × (maximum feature value−average feature value) + average feature value (12)
α and β are set to optimum values for each feature amount. For example, in the case of the feature quantity of “the heat exchanger intake air temperature−the heat exchanger blown air temperature” in the above equation (1), α = 0.2 and β = 0.7 are set. In the case of the feature amount defined by the above equation (2), α = 0.2 and β = 0.6 are optimal.

  Even when two feature quantities are used or when four or more feature quantities are used, the same determination rule rule as the above formulas (9) and (10) is applied according to the number of feature quantities.

The predictive value and limit value are set and stored based on the data during the cooling operation. Here, a method for setting the predictor value and the limit value will be described with reference to the flowchart of FIG. FIG. 5 is a flowchart for setting a predictor value and a limit value by the cooling capacity or frost formation amount estimation / defrosting permission unit according to the first embodiment.
When the defrosting operation is completed and the cooling operation is started, the cooling capacity or the amount of frost formation estimation / defrosting permission means starts the operation for setting the predictive value and the limit value in FIG. In FIG. 5, it is first determined whether or not the learned flag is 0 (ST1). Initially, the learned flag is 0. If initial learning is not performed (if the learned flag is 0), it is then determined whether or not the internal temperature is equal to or lower than the internal target temperature + k (ST2). This is because the internal temperature is high at the initial stage of cooling after the start of defrosting, and it is necessary to start learning after the internal temperature has decreased to some extent. Then, if the internal temperature has cooled down to near the target temperature (for example, if the target temperature is + 5 ° C or less), measure or acquire the feature value data to be used, and calculate the average value and maximum value of each feature value data. And learn (ST3). The average value and the maximum value of the feature amount are sequentially updated during the learning time. However, feature amount data that seems to be extremely distant noise is excluded. When the number of learned feature quantity data reaches a certain number, for example, 30, or when the learning time has passed a certain time, for example, 2 hours, the learning is completed (ST4) and the learned flag is set to 1. (ST5). Then, according to the equations (11) and (12), the predictor value and the limit value are set for each feature amount (ST6). The sign value is smaller than the limit value before reaching the limit value, and therefore α is set to a value smaller than β.

  The number of data for learning the feature data is preferably about 20 to 30 in view of data variation, but is not limited thereto. Here, the predictive value and the limit value are obtained by adding the average value to the difference between the maximum value and the average value multiplied by a constant. However, the present invention is not limited to this, and the showcase heat exchanger 27 Any other formula that can set the limit value and predictive value of the cooling capacity or the amount of frost formation may be used.

When learning is completed and the predictive value and limit value for each feature amount are set, the cooling capacity or frost amount estimation / defrost permission means enters the frost amount or cooling capacity decrease determination (estimation). Next, the determination operation will be described with reference to FIG. FIG. 6 is a flowchart showing an example of the estimation of the cooling capacity or frost amount of the heat exchanger by the cooling capacity or frost amount estimation / defrosting permission means in the first embodiment. In this example, the case where there are three feature amounts is described as an example, but the number of feature amounts is not limited to this.
First, it is determined whether the initial learning is completed by checking whether the learned flag is 1 (ST11). If the initial learning is completed, the process proceeds to the next, whether the feature quantity 1 exceeds the limit value 1 (ST12), the feature quantity 2 exceeds the limit value 2 (ST13), or the feature quantity 3 reaches the limit value 3. Either the feature value 1 exceeds the predictive value, the feature value 2 exceeds the predictive value 2, and the feature value 3 exceeds the predictive value 3 (ST15). If it is determined that the amount of frost formation has increased or the cooling capacity has decreased, it is determined that defrosting needs to be performed, and the defrost flag is set to 1 (ST16). That is, if all the feature values exceed the predictive value, it is determined that the frost limit is reached, and if any one of the feature values exceeds the limit value, it is determined that the frost limit is reached. Flag). In this way, by using different determination logics using the same feature amount, it is possible to detect the cooling capacity decrease due to the frost amount limit early and reliably.

  However, even if the defrost flag is set as described above (even if the operation start permission signal of the heater 40 is issued), the defrost is not performed immediately, but waits until the set time in the next timer, The defrosting operation is performed in synchronization with the timer. Next, the operation will be described with reference to FIG. FIG. 7 is a flowchart showing an example of the defrosting operation control of the heater 40 based on the operation start permission signal and the defrosting execution signal by the control board 42 in the showcase. In FIG. 7, it is determined whether or not the defrost flag is set to 1 (ST21). If the defrost flag is set, it is determined whether or not the defrost timer has reached the specified time (ST22). ) If the designated time is reached, the learned flag and the defrost flag are cleared (ST23), and the defrost operation is performed (ST24). That is, even if the defrost flag is set, defrosting is not performed unless the defrost timer reaches the designated time.

  Note that the defrost timer may be built in the showcase 13 or may be installed outside the showcase. Also, means having the same function as the defrost timer may be incorporated in the showcase control board 42. In addition, the defrost timer may be one that can set a normal clock-type time, one that can set only the elapsed time, and one that is analog or digital. Moreover, the defrost timer should just be what can send a signal to the control board 42 in a showcase for every fixed time or a designated time. That is, any defrosting timer may be used as long as it functions as a timer, and other than the timer, for example, a command from a personal computer or other external device may be used.

  The refrigerant circulating in the refrigeration cycle of the showcase 13 may be any refrigerant, such as carbon dioxide, hydrocarbons, natural refrigerants such as helium, refrigerants that do not contain chlorine, such as alternative refrigerants such as HFC410A and HFC407C, or existing refrigerants. Any of chlorofluorocarbon refrigerants such as R22 and R134a used in products may be used.

  The compressor 11 may be of any type such as reciprocating, rotary, scroll, screw, etc., and may be a variable speed or a fixed speed.

  In addition, here, the case where the temperature sensor for detecting the evaporation temperature of the refrigerant is installed on the inlet side of the heat exchanger has been described as an example. However, any position where the evaporation temperature of the refrigerant can be detected may be used. It may be installed near the center of the exchanger. Further, if a pressure sensor for measuring the pressure of the refrigerant is installed in any of the flow paths from the suction of the compressor to the expansion means and converted into the evaporation temperature, the refrigerant temperature sensor may not be installed. .

  In addition, here, the value calculated from the air temperature and the refrigerant temperature is used as the feature amount for determining the start of the defrosting operation. However, the value is not limited to this, and it is possible to determine the cooling capacity or the decrease in the cooling capacity. Anything is acceptable. For example, if the flow rate of the refrigerant is known, the cooling capacity can be directly calculated and grasped by measuring the pressure and temperature, and calculating the inlet refrigerant enthalpy and outlet refrigerant enthalpy of the heat exchanger. It can be used to determine necessity.

  In addition, here, the case where two showcases 13 are connected to the refrigerator 11 has been described as an example, but the present invention is not limited to this, and there may be one or even three or more. I do not care.

  In addition, the case where the liquid reservoir 24 is built in the refrigerator 11 has been described as an example, but naturally, the configuration without the liquid reservoir 24 may be used, and the operational effect is not changed at all.

  Moreover, although the case where the compressor 21, the outdoor heat exchanger 22, the fan 23 for outdoor heat exchangers, and the liquid reservoir 24 were incorporated in the refrigerator 11 was demonstrated as an example, it is not restricted to this, The outdoor heat exchanger 22 and the outdoor heat exchanger fan 23 may be of a remote condenser type in which they are placed separately from the compressor 21.

  Further, the case where the refrigeration apparatus is an open showcase without a door has been described as an example, but a reach-in showcase with a door, a unit cooler used in a refrigerator / freezer warehouse, and the like may be used. If it has a similar structure, the same effect can be obtained with an air conditioner such as a room air conditioner or a packaged air conditioner.

  Further, although an explanation has been given by taking as an example a stand-alone type showcase in which the refrigerator 11 and the showcase 13 are separate, the built-in type in which the showcase 13 includes a compressor 21, an outdoor heat exchanger 22, and the like. The showcase may be the same effect.

  Furthermore, as the frost formation amount estimation unit or the cooling capacity estimation unit in the above embodiment, a configuration in which the frost formation amount of the showcase heat exchanger 27 or the equivalent thereof is directly measured may be employed, and the same effect is achieved. . For example, as shown in FIG. 8, an optical frosting sensor 47 composed of a light emitting part 47a and a light receiving part 47b of an optical sensor such as an LED is disposed in the vicinity of the fin 27a of the heat exchanger 27 and depends on the thickness of the frost. A change in the reflectance (ratio of the amount of received light with respect to the amount of emitted light) may be measured, and the change may be converted into a frost amount by the light quantity determination control unit 48. Moreover, an electrode may be arrange | positioned in the position which touches frost, and you may make it measure the thickness of frost from the difference in the electrostatic capacitance of frost and air. Moreover, you may make it measure the surface temperature of frost with the radiation temperature sensor etc. which measure the temperature of a target object non-contactingly with a thermopile etc. FIG. As the frost grows, the surface temperature rises and approaches the air temperature. Therefore, the surface temperature of the frost is measured, converted into the thickness of the frost, and the amount of frost formation can be grasped.

  As described above, the refrigeration apparatus of the present embodiment detects energy loss by detecting a decrease in the amount of frost on the heat exchanger or the cooling capacity and performing a defrosting operation, thereby preventing energy from being wasted. By performing defrosting operation in synchronization with the timer, it is possible to perform defrosting operation according to the time when there are few customers such as closing time of the store, and it does not disturb the operation of the store and saves energy be able to.

Embodiment 2. FIG.
In the first embodiment, the case where a plurality of showcases operate separately has been described, but in reality, the plurality of showcases may be controlled in conjunction with each other. In the second embodiment, this will be described with reference to FIG. Note that the description of the same parts as those in Embodiment 1 is omitted.

  In FIG. 9, the showcases are divided into three groups, group 1 (showcases 13a to 13c), group 2 (showcases 13d to 13h), and group 3 (showcases 13i to 13k). Several are installed adjacent to each other. In such a case, if the defrosting operation is performed separately in each adjacent showcase, the heat during defrosting is transmitted to the adjacent showcase through the wall of the showcase, so extra cooling energy is generated and power consumption Will increase. In addition, the temperature of food near the wall surface in the showcase cabinet rises due to the effect of defrosting heat from adjacent showcases, and there is a problem in terms of quality. Therefore, a plurality of adjacent showcases are grouped together and the defrosting operation is set to be performed in groups. The group management of these showcases is performed by the integrated controller 15. The integrated controller 15 is connected to the in-showcase control board 42 (see FIG. 3) in each of the showcases 13a to 13k.

  That is, the final determination of whether or not to start defrosting is performed by the control board 42 in each showcase 13a to 13k. If it is determined that defrosting is necessary, a defrost flag is set for each showcase. And the integrated controller 15 acquires the value of a defrost flag from each control board 42 in each showcase by communication, and if even one defrost flag stands among the showcases of each group, all the shows of the group will be shown. A signal is sent to the case so as to perform the defrosting operation in synchronization with the designated time in the next defrosting timer. If no defrost flag is set for any showcase in the group, the integrated controller 15 does not issue a defrost signal (defrost execution signal) to the showcase for that group, and skips the defrost operation. The defrosting operation is not performed until the designated time at the next timer. By doing in this way, useless energy intrusion through the wall due to random defrosting operation of the showcase is prevented, and reliable energy saving is achieved.

  A plurality of groups of showcases may be connected to one integrated controller, or each group may be connected to a separate integrated controller.

  Further, the defrost timer may be connected to the integrated controller 15 or may be connected to each in-showcase control board 42. When connected to the integrated controller 15, there is an advantage that only one timer is required and the configuration can be made inexpensively. On the other hand, when connected to the in-showcase control board 42, the integrated controller 15 adds the 1 or 0 signal received from between the in-showcase control boards 42, and whether or not defrosting is present depending on whether or not it is 1 or more. There is an advantage that the integrated controller 15 does not need to have complicated calculation means.

  In addition, the communication between the integrated controller 15 and the control board 42 in each showcase can be performed using any communication method such as a digital signal of 1 or 0, an analog voltage signal, a no-voltage contact signal, or a character string communication method. I do not care.

  Further, the connection between the integrated controller 15 and each in-showcase control board 42 may be any method as long as signals and data can be transmitted and received, and may be wired, wireless, or other communication means.

  When a plurality of integrated controllers 15 are installed, signals may be exchanged between the integrated controllers, and these may be linked and controlled.

  Further, the integrated controller 15 may be installed near the refrigeration apparatus 13, or may be installed remotely via the Internet or a telephone line. When installed near the refrigeration apparatus, the control speed can be improved, a stable control system can be obtained, and when installed remotely, the local controller installation space can be reduced.

  As described above, the refrigeration system according to the present embodiment can prevent energy from entering through the wall of the showcase by matching the defrosting timings in adjacent showcases, and can surely save energy.

Explanatory drawing which shows the installation to the shop of the freezing apparatus which concerns on Embodiment 1 of this invention. The refrigerant circuit figure of the freezing apparatus which concerns on Embodiment 1 of this invention. The internal block diagram of the showcase of the refrigeration apparatus which concerns on Embodiment 1 of this invention. The figure which shows the change of the air temperature in the heat exchanger of a freezing apparatus. The flowchart which sets the predictive value and limit value by the estimation / defrost permission means of the cooling capacity or the amount of frost formation in Embodiment 1. FIG. The flowchart of the estimation of the cooling capacity or the amount of frost formation of a heat exchanger by the estimation / defrost permission means of the cooling capacity or the amount of frost formation in Embodiment 1, and a defrost permission setting. The flowchart of the defrost operation control based on the operation start permission signal and defrost execution signal in Embodiment 1. Explanatory drawing which shows an example of the optical frosting detection method. The detail drawing of the connection figure to the store of the refrigerating system which shows Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Outdoor unit for air conditioning, 11 Refrigerator for refrigeration or freezing, 12 Indoor unit for air conditioning, 13 Showcase for refrigeration or freezing, 14 stores, 15 Integrated controller, 21 Compressor, 22 Outdoor heat exchanger, 23 Outdoor heat Exchanger fan, 24 liquid reservoir, 25 on-off valve, 26 expansion means, 27 showcase heat exchanger, 28 showcase heat exchanger fan, 30 showcase heat exchanger refrigerant inlet temperature sensor, 31 showcase heat exchanger intake air Temperature sensor, 32A, 32B Showcase heat exchanger blown air temperature sensor, 40 heater or other defrosting means, 41 timer, 42 control board in showcase, 43 microcomputer (estimation of cooling capacity or amount of frost formation / defrosting) Permission means).

Claims (8)

A heat exchanger, cooling operation means for supplying cold heat to the heat exchanger, defrosting operation means for defrosting frost adhering to the heat exchanger, and cooling capacity or cooling of the heat exchanger in the cooling operation Cooling capacity estimating means for estimating a decrease in capacity, and defrost permission means for permitting the start of operation of the defrosting operation means based on the estimation result of the cooling capacity estimation means,
The defrosting operation means is a refrigeration apparatus that defrosts the heat exchanger in synchronization with a defrosting execution signal from inside or outside the apparatus when the defrosting permission means permits the operation start. And
The cooling capacity estimation means uses a plurality of feature quantities representing the cooling capacity of the heat exchanger, each limit value set for each of the plurality of feature quantities and each predictive value before reaching each limit value, and A refrigeration apparatus that compares with the limit value and the predictor value corresponding to each of a plurality of feature amounts and performs estimation based on the comparison result . A heat exchanger, cooling operation means for supplying cold heat to the heat exchanger, defrosting operation means for defrosting frost adhering to the heat exchanger, and cooling capacity or cooling of the heat exchanger in the cooling operation Cooling capacity estimating means for estimating a decrease in capacity, and defrost permission means for permitting the start of operation of the defrosting operation means based on the estimation result of the cooling capacity estimation means,
The defrosting operation means does not defrost the heat exchanger even if a defrosting execution signal is input from inside or outside the apparatus when the defrosting permission means does not permit the operation start, A refrigeration apparatus that extends the defrost start until the next defrost timing ,
The cooling capacity estimation means uses a plurality of feature quantities representing the cooling capacity of the heat exchanger, each limit value set for each of the plurality of feature quantities and each predictive value before reaching each limit value, and A refrigeration apparatus that compares with the limit value and the predictor value corresponding to each of a plurality of feature amounts and performs estimation based on the comparison result . The cooling capacity estimating means determines that the cooling capacity is required to be decreased when any one of the plurality of feature values exceeds the corresponding limit value, and the plurality of feature values is reduced. 3. The refrigeration apparatus according to claim 1 , wherein when all of the above values exceed the corresponding predictive values, it is determined that the cooling capacity is reduced, which requires the start of the defrosting operation . The plurality of feature amounts are:
(Intake air temperature of the heat exchanger−outlet air temperature of the heat exchanger),
(Intake air temperature of the heat exchanger−outlet air temperature of the heat exchanger) / (intake air temperature of the heat exchanger−refrigerant evaporation temperature of the heat exchanger),
Chamber temperature = (Suction air temperature of the heat exchanger + Blowout air temperature in the chamber) / 2
≒ (Intake air temperature of the heat exchanger + Outlet air temperature of the heat exchanger) / 2
(Intake air temperature of the heat exchanger−Blow air temperature of the heat exchanger) / (Internal temperature−Refrigerant inlet temperature of the heat exchanger),
(Suction air temperature of the heat exchanger−refrigerant evaporation temperature of the heat exchanger),
(The internal temperature−the refrigerant evaporating temperature of the heat exchanger) and (the intake air temperature of the heat exchanger−the refrigerant evaporating temperature of the heat exchanger) + (the internal temperature−the refrigerant evaporating of the heat exchanger) temperature),
The refrigeration apparatus according to any one of claims 1 to 3, wherein the refrigeration apparatus is at least two of the quantities. The plurality of feature amounts are:
(Intake air temperature of the heat exchanger−outlet air temperature of the heat exchanger),
(Intake air temperature of the heat exchanger−refrigerant evaporation temperature of the heat exchanger) / (intake air temperature of the heat exchanger−blow air temperature of the heat exchanger),
Chamber temperature = (Suction air temperature of the heat exchanger + Blowout air temperature in the chamber) / 2
≒ (Intake air temperature of the heat exchanger + Outlet air temperature of the heat exchanger) / 2
(The internal temperature−the refrigerant inlet temperature of the heat exchanger) / (the intake air temperature of the heat exchanger−the blown air temperature of the heat exchanger),
(Suction air temperature of the heat exchanger−refrigerant evaporation temperature of the heat exchanger),
(The internal temperature−the refrigerant evaporating temperature of the heat exchanger) and (the intake air temperature of the heat exchanger−the refrigerant evaporating temperature of the heat exchanger) + (the internal temperature−the refrigerant evaporating of the heat exchanger) temperature),
The refrigeration apparatus according to any one of claims 1 to 3, wherein the refrigeration apparatus is at least two of the quantities. Intake air temperature detecting means for detecting the intake air temperature installed in the air passage on the inlet side of the heat exchanger, and one or more outlets installed in the air path on the outlet side of the heat exchanger for detecting the air temperature An air temperature detection means, a refrigerant temperature detection means installed at any position on the inlet side of the heat exchanger or in the refrigerant flow path in the heat exchanger, or for calculating the saturation temperature of the refrigerant. 6. The refrigeration apparatus according to claim 1 , further comprising: a refrigerant pressure detection unit. 7. The refrigeration apparatus according to claim 6, wherein when a plurality of the blown air temperature detection means are installed, the average temperature or one of them is used as the blown air temperature. 8. The predictor value and the limit value are set based on an average value and a maximum value of each feature amount during a predetermined time during the initial cooling operation. The refrigeration apparatus described in 1 .

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