JP2017537300A - refrigerator - Google Patents

Abstract

Disclosed is a refrigerator including a heat storage material containing a phase change material. The refrigerator includes a refrigerating room (6) for accommodating a cooling object, a first evaporator (10) for cooling the refrigerating room, and a second evaporator (12) for cooling the phase change material. A vapor compression cooling system. A valve (15) is provided to control the flow of refrigerant to the first and second evaporators in accordance with the cooling load applied to the refrigerator. When the refrigerator is subjected to a relatively low cooling load, the refrigerant flows into the second evaporator (12) to cool the phase change material and when the refrigerator is subjected to a relatively high cooling load. The refrigerant flows into the first evaporator (10), thereby providing the refrigerator with improved cooling performance due to the first evaporator and the phase change material. In a preferred embodiment, when the refrigerator is subjected to a relatively low cooling load, the refrigerant flows into both the first evaporator (10) and the second evaporator (12) and the refrigerator is relatively high. When receiving a cooling load, the refrigerant generally flows only into the first evaporator (10). [Selection] Figure 1

Description

  The present invention relates to a refrigerator using a phase change material as a heat storage material. The present invention is particularly relevant to commercial bottle coolers that have relatively high peak cooling loads and are installed in bars, pubs and the like.

  Refrigerated display cabinets, such as bottle coolers, are widely used in entertainment facilities to refrigerate beverages for sale to customers. Such a refrigerated display cabinet is usually provided with a transparent or transparent door through which the inside beverage can be seen so that the user can see the beverage inside.

  The bottle cooler has a relatively high cooling load, for example, when the door is frequently opened to take out the beverage of the customer or when a large number of beverage containers that have not been cooled are replenished.

  In order to cope with the high cooling load, the store bottle cooler is equipped with a vapor compression cooling system that is larger than that normally provided in a domestic refrigerator of similar capacity. For this reason, this type of bottle cooler operates inefficiently compared to a household refrigerator of the same size.

  In addition, even when considering reasons other than size, because the market for home refrigerators is larger, development to increase the efficiency of compressors used is being promoted and is generally used in commercial refrigerators A relatively large compressor is less economical than a relatively small compressor used in a home refrigerator.

  Furthermore, it is necessary to use a material with a relatively low thermal insulation in order to make the door transparent or transparent, which impairs the overall efficiency of the bottle cooler. This problem is particularly serious in the case of a display cabinet that is operated with its front open (that is, without a door) during business hours in a store that sells refrigerated products or cooled products.

  Patent Document 1 relates to a system having two refrigeration rooms, one for refrigeration and the other for refrigeration, each having an evaporator. In order to control the temperature of these refrigerator compartments, the flow of the refrigerant is induced between the refrigerator compartment and the evaporator using a control device. A phase change material can then be used in conjunction with either evaporator.

  Patent Document 2 relates to a refrigerated display cabinet in which a phase change material functioning as a heat accumulator is provided on an inner wall.

Canadian Patent No. 2103978 German utility model No. 202006010757

  The present invention aims to increase the efficiency of a refrigerated display cabinet, and is considered useful for any refrigeration apparatus that regularly receives large load fluctuations.

  According to the present invention, a refrigerator having a refrigerator compartment for accommodating a cooling object is provided, and the refrigerator includes a heat storage material including a phase change material, a first evaporator and a phase change material for cooling the refrigerator compartment. A vapor compression cooling system having a second evaporator for cooling the refrigerant, and control means for controlling the flow of refrigerant to the first evaporator and the second evaporator according to the cooling load applied to the refrigerator; When the refrigerator is subjected to a relatively low cooling load, the refrigerant flows into the second evaporator to cool the phase change material, and the refrigerator is subjected to a relatively high cooling load. The refrigerant flows into the first evaporator, thereby providing the refrigerator with improved cooling performance by the first evaporator and the phase change material.

  When the refrigerator is subjected to a relatively low cooling load, some cooling effect is obtained by the phase change material and the second evaporator, so that the refrigerant is generally the second evaporator to cool the phase change material. It is assumed that it can only flow in. However, in a preferred embodiment, the refrigerant flows into both the first evaporator and the second evaporator when the refrigerator is subjected to a relatively low cooling load.

  When the refrigerator is subjected to a relatively high cooling load, it is preferable to maximize the cooling effect obtained by the first evaporator by guiding the refrigerant to only the first evaporator.

  By guiding the refrigerant to flow to the second evaporator during periods of low cooling load, the surplus capacity in the system can be achieved by lowering the phase change material (PCM) to a lower energy state, eg gas to liquid or liquid to solid. Can be used to cool down.

  When the refrigerator is subjected to a high cooling load, both the first evaporator and the heat storage material can be used simultaneously (sequentially) to cool the air. Since the first evaporator and the heat storage material are separately provided, the cooling surface area is increased and cooling can be performed more rapidly. The PCM preferentially (primarily or completely) the first vaporization over the second vaporizer, since at least a portion, if not completely, is in a lower energy state since the previous low cooling load period. The flow of refrigerant can be directed to the vessel, which improves the cooling of the air obtained by the first evaporator. The refrigerant flow to the second evaporator is limited or turned off, but the PCM in the low energy state continues to cool the air while gradually transitioning to the higher energy state. Thus, during peak load periods, refrigerant can be used to primarily cool the air rather than PCM.

  By controlling the refrigerant in this way, the cooling efficiency by the system is improved. The heat storage material can provide the same effect as dispersing the cooling load over a longer period. This allows the system to use a smaller and more efficient compressor while minimizing the effect of the refrigerator.

  Moreover, even if a temporary power failure occurs, it is possible to continue cooling in the refrigerator with the heat storage material.

  The state of the cooling load is generally specified by detecting a temperature difference between an actual temperature and a predetermined temperature.

  In order to improve the cooling rate of the air in the refrigerator compartment, it is provided with means for circulating the air in the refrigerator compartment through the cooling surface of the heat storage material, more preferably through the first evaporator. preferable. Forced air cooling may be particularly desirable for display refrigerators where convection or conduction cooling may not be practical to obtain the cooling rate required to handle higher heat loads. Preferably, the means for circulating air has a fan. The air is preferably circulated out of the refrigerator compartment, passed through the cooling surface of the heat storage material, passed through the first evaporator, and returned to the refrigerator compartment.

  The refrigerator has a duct interposed between the wall of the refrigerator compartment and the outer heat insulating wall of the refrigerator. The heat storage material can be installed in the duct. In order to obtain the maximum surface area, it is preferable to install the heat storage material in the duct so that both outer sides of the heat storage material are in contact with the air flowing through the duct. That is, air passes through both sides of the heat storage material. In addition, the heat storage material is preferably formed in an elongated shape having a longitudinal axis parallel to the axis of the duct so that most of the surface area is exposed to the passing air.

  Preferably, the first evaporator is arranged downstream of the heat storage material, thereby increasing the cooling effect of the PCM to cool the air before passing through the first evaporator during the high cooling load period. Fully available.

  The vapor compression cooling system includes a compressor, a condenser, at least one expansion device, a first path through which the refrigerant flows into the first evaporator and returns to the compressor, and the refrigerant is the second. And a second path that circulates so as to flow into the evaporator and return to the compressor. In a preferred embodiment, the second path downstream of the second evaporator joins the first path upstream of the first evaporator.

  Control means for controlling the flow of refrigerant between the first evaporator and the second evaporator directs the refrigerant to both evaporators (at the same flow rate or different flow rates), or completely or In general, it can function to direct to one or the other evaporator.

  Preferably, the control means for controlling the flow of the refrigerant to the first evaporator and the second evaporator according to the cooling load includes a valve and a controller. Preferably, the controller controls the position of the valve according to the cooling load. As described above, a configuration in which the cooling load is confirmed by specifying the difference between the temperature of at least one of the air in the refrigerator compartment and the duct and the predetermined temperature is preferable. The temperature of at least one of the air in the refrigerator compartment and the duct is preferably specified by a temperature sensor.

  The controller is preferably configured to control the position of the valve in accordance with the composition ratio of the two phases of PCM.

  Also, in a preferred embodiment, the valve has only two position states: in the first position, the refrigerant is directed to both evaporators, and in the second position, the refrigerant is directed only to the first evaporator. Is done. That is, the valve is preferably a bistable valve. Thereby, a simplified control system can be configured.

  The controller is preferably configured to control the operation and speed of at least one of the operation of the compressor and the means for circulating the air.

  The PCM preferably contains water as a main component, which may further contain one or more solutes for adjusting the freezing point.

  The second evaporator can be configured to be partially or fully disposed within the PCM so that the PCM is cooled from the inside to the outside. The heat storage material preferably has a means for specifying the degree to which the state of the PCM is changing. This information can be used by the controller to control the flow of refrigerant to the second evaporator or to control the compressor.

  In another aspect, the present invention provides a refrigerator having a refrigeration room for containing a cooling object, the refrigerator for cooling the refrigeration room during a period when the refrigerator is subjected to a relatively high cooling load. In order to cool the phase change material when the refrigerator is subjected to a relatively low cooling load, the heat storage material containing the phase change material, the first evaporator through which the refrigerant flows to cool the refrigerator compartment A vapor compression cooling system having a second evaporator through which the refrigerant flows, and control means for controlling the flow of the refrigerant to the first evaporator and the second evaporator according to the cooling load applied to the refrigerator. Prepare.

  The invention will be described by way of example with reference to the following drawings.

It is a partial schematic sectional side view of the refrigerated display cabinet by this invention. 1 is a schematic view of a refrigerant circuit according to the present invention. It is a partial schematic side view which shows a thermal storage material.

  Referring to FIG. 1, the refrigerated display cabinet includes a heat insulating casing 1 having a glass door 2. The insulating casing is preferably composed of a vacuum-formed insulating plate in combination with high density polyurethane for structural rigidity. The glass door may be double glazed or preferably triple glazed. Krypton gas can be supplied between the glass plates to enhance the heat insulation. The cabinet is mounted on a base that holds components of a vapor compression cooling system having a compressor 3, a condenser 4, and a fan 5 associated with the condenser 4.

  The cabinet 1 has a compartment 6 in which the product contained therein is cooled. The compartment 6 can be provided with illumination, and the illumination is preferably energy efficient LED illumination. The illumination power supply is preferably arranged outside the compartment 6. In order to further reduce the equipment heat load, an LED light source can also be placed outside the compartment 6 and light is guided into the compartment 6 by suitable means such as light guides, optical fibers and aerogels, etc. .

  Air is drawn from the compartment 6 into the duct 7 by the fan 7A for cooling. The duct 7 is partly defined by a gap between the inner wall 6A forming at least the compartment 6 and the inner wall of the insulating casing 1. The bottom of the compartment 6 may be defined by a first evaporator 10 (described below) or its casing.

  1 and 2 show a refrigerant circuit. The condensed refrigerant from the condenser 4 can selectively flow back to the compressor 3 along one of the two paths. The first path 8 carries the refrigerant through the first expansion device 9A and the first evaporator 10, which is typically a finned tube evaporator. The second path 11 passes the refrigerant through the second expansion device 9B and the second evaporator 12 incorporated in the heat storage unit 13 holding the phase change material (PCM) 14, which in this case is water. Carry.

  The refrigerant flow is controlled by a valve 15 downstream of the condenser 4. The position state of the valve 15 is controlled by a controller 16, which is also used to control the compressor 3, the condenser fan 5 and the duct fan 7A.

  As shown in FIGS. 1 and 2, the system is configured such that the refrigerant flowing out of the second evaporator 12 returns to the compressor 3 through the first evaporator 10. In addition, it can change suitably to other structures, such as two separate paths merge upstream of the compressor 3.

  Referring back to FIG. 1, the first evaporator 10 and the heat storage unit 13 both cool the air through which the air circulating through the duct 7 passes through the cooling surfaces of the heat storage unit 13 and the first evaporator 10. It is installed as follows.

  The temperature sensor 17 detects the temperature of the air exiting the compartment 6 and supplies a corresponding signal to the controller 16.

  The first evaporator 10 is arranged downstream of the heat storage material 13 so that the hottest warm air passes through the heat storage material 13 and heat transfer from the PCM 14 to the warm air increases during the high cooling load period.

  As shown in FIG. 3, the second evaporator 12 is incorporated in the heat storage material 13, so that the solidification of the PCM 14 first occurs in the central region 14A, and the central region is mainly ice, outside of it. Is an outer region 14C mainly made of water. The degree to which the PCM 14 is solidified or melted is detected by measuring the position of the interface 14B between ice and water. This measurement is performed by a sensor (group) 18 that measures the conductivity of the PCM 14 at a point between the outer wall of the heat storage material 13 and the evaporator 12. A signal from the sensor (group) 18 is received by the controller 16. Such a configuration is known in the technical field of heat storage materials incorporating PCM.

  In order to maximize the cooling surface exposed to the air by the heat storage material 13 in the duct 7, the heat storage material 13 is removed from both the wall 6 A and the heat insulating casing 1 so that air can pass on both sides in the width direction. They are spaced apart.

  Returning to FIG. 1 and FIG. 2, the operation of the refrigerator will be described. When the refrigerator is operating in a steady state, that is, when the temperature of the air flowing out of the compartment is a predetermined temperature or a temperature close thereto, the controller 16 cools the PCM 14 in the heat storage material 13 to cool and solidify it. Operates the valve 15 so that is pumped along the second path 11 through the second evaporator 12. Also, once solidification of PCM 14 is detected by sensor 18, controller 16 can turn off or decelerate compressor 3 and condenser fan 5 to save energy. Generally, such a compressor 3 is either on or off, but can be decelerated in some cases.

  By applying such control, in order to ensure sufficient solidification of the PCM 14 to obtain additional cooling during the next high cooling load period, the solidification state of the PCM 14 during steady operation is, for example, fully solidified. Control between 20% melting. If it is determined that the PCM 14 is sufficiently solidified during steady operation, the controller 16 can turn off or decelerate the compressor 3 to reduce energy consumption.

  In addition, the controller can control the operation or speed of the fan 7A during its steady state as a further way to regulate and control the compartment air temperature.

  In a specific embodiment of steady operation, the refrigerant flows through both evaporators and controls the product temperature by adjusting the temperature of the air exiting the compartment. The air temperature is controlled by adjusting the speed of the fan 7A and switching the compressor 3 and the condenser fan 5 on and off. Further, when the amount of coagulated PCM measured by the sensor 18 falls below the threshold value, the compressor 3 and the condenser fan 5 are operated. If the air temperature becomes too low, the fan 7A is decelerated. When the PCM reaches 100% solidification or nears it, the compressor and condenser fan are stopped and the air is cooled with the heat storage material or PCM. As the air temperature rises, the fan speed is accelerated and when a further threshold temperature is reached, the compressor and condenser fan are turned on.

  During a period when the heat load is relatively high, i.e. when the sensor 17 detects that the temperature of the air from the compartment 6 is higher than a predetermined temperature (possibly beyond an acceptable range from the predetermined temperature). The controller 16 adjusts the valve 15 so that the refrigerant is preferentially directed to the first evaporator 10. As a result, the first evaporator 10 can obtain a larger cooling power for cooling the circulating air. The cooling load applied to the first evaporator 10 is also reduced by the cooling effect on the air by the heat storage unit 13 through which the air first passes.

  When it is detected that the temperature has dropped to or near a predetermined temperature, the controller 16 causes the refrigerant or a portion of its flow to be directed through the second evaporator 12 to re-solidify the PCM 14. The valve 15 is operated so that the steady state is finally reached.

  It should be understood that many variations can be made to the above-described embodiments as appropriate without departing from the scope of the present invention as defined in the appended claims. For example, a refrigerator may include more than two evaporators. The temperature sensor may instead be installed in the compartment 6.

  As described above, the heat storage material can realize that the refrigerator continues cooling when a temporary power failure occurs. On the other hand, a battery may be provided for operation of the vapor compression system when a power failure occurs.

The present invention is related to a refrigerator using a phase change material as a heat storage material.

For example, refrigerated display cabinets such as commercial bottle coolers are widely used in entertainment facilities such as bars and pubs to refrigerate beverages for sale to customers. Such a refrigerated display cabinet is usually provided with a transparent or transparent door through which the inside beverage can be seen so that the user can see the beverage inside.

  The bottle cooler has a relatively high cooling load, for example, when the door is frequently opened to take out the beverage of the customer or when a large number of beverage containers that have not been cooled are replenished.

  In order to cope with the high cooling load, the store bottle cooler is equipped with a vapor compression cooling system that is larger than that normally provided in a domestic refrigerator of similar capacity. For this reason, this type of bottle cooler operates inefficiently compared to a household refrigerator of the same size.

  In addition, even when considering reasons other than size, because the market for home refrigerators is larger, development to increase the efficiency of compressors used is being promoted and is generally used in commercial refrigerators A relatively large compressor is less economical than a relatively small compressor used in a home refrigerator.

  Furthermore, it is necessary to use a material with a relatively low thermal insulation in order to make the door transparent or transparent, which impairs the overall efficiency of the bottle cooler. This problem is particularly serious in the case of a display cabinet that is operated with its front open (that is, without a door) during business hours in a store that sells refrigerated products or cooled products.

  Patent Document 1 relates to a system having two refrigeration rooms, one for refrigeration and the other for refrigeration, each having an evaporator. In order to control the temperature of these refrigerator compartments, the flow of the refrigerant is induced between the refrigerator compartment and the evaporator using a control device. A phase change material can then be used in conjunction with either evaporator.

  Patent Document 2 relates to a refrigerated display cabinet in which a phase change material functioning as a heat accumulator is provided on an inner wall.

Canadian Patent No. 2103978 German utility model No. 202006010757

  The present invention aims to increase the efficiency of a refrigerated display cabinet, and is considered useful for any refrigeration apparatus that regularly receives large load fluctuations.

According to the present invention, a refrigerator having a refrigerator compartment for accommodating a cooling object is provided, and the refrigerator includes a heat storage material including a phase change material, a first evaporator and a phase change material for cooling the refrigerator compartment. A vapor compression cooling system having a second evaporator for cooling the refrigerant, and control means for controlling the flow of refrigerant to the first evaporator and the second evaporator in accordance with the cooling load applied to the refrigerator compartment with the door, the lower have field if the cooling load is relatively to the refrigerator compartment, the refrigerant flows into at least a second evaporator to cool the phase change material, a relatively high cooling load on the refrigeration compartment the have field case, the refrigerant that flows into the first evaporator, cooling performance was improved by the phase change material first evaporator is provided in the refrigerating chamber.

The low have field if the cooling load is relatively to the refrigerator compartment, because the degree of cooling effect obtained by the phase change material and a second evaporator, the second evaporator to the refrigerant to cool the phase change material It is assumed that it can only flow in. However, in a preferred embodiment, the cooling load on the refrigeration compartment is relatively low have field coupling, the refrigerant flows into both the first evaporator and the second evaporator.

The high have field if the cooling load is relatively to the refrigerator compartment, by inducing the refrigerant only to the first evaporator, it is preferable to maximize the cooling effect obtained by the first evaporator.

  By guiding the refrigerant to flow to the second evaporator during periods of low cooling load, the surplus capacity in the system can be achieved by lowering the phase change material (PCM) to a lower energy state, eg gas to liquid or liquid to solid. Can be used to cool down.

The cooling load is high have field coupling to the refrigerating compartment, both at the same time (sequentially) in the first evaporator and the heat storage material in order to cool the air can be used. Since the first evaporator and the heat storage material are separately provided, the cooling surface area is increased and cooling can be performed more rapidly. The PCM preferentially (primarily or completely) the first vaporization over the second vaporizer, since at least a portion, if not completely, is in a lower energy state since the previous low cooling load period. The flow of refrigerant can be directed to the vessel, which improves the cooling of the air obtained by the first evaporator. The refrigerant flow to the second evaporator is limited or turned off, but the PCM in the low energy state continues to cool the air while gradually transitioning to the higher energy state. Thus, during peak load periods, refrigerant can be used to primarily cool the air rather than PCM.

  By controlling the refrigerant in this way, the cooling efficiency by the system is improved. The heat storage material can provide the same effect as dispersing the cooling load over a longer period. This allows the system to use a smaller and more efficient compressor while minimizing the effect of the refrigerator.

  Moreover, even if a temporary power failure occurs, it is possible to continue cooling in the refrigerator with the heat storage material.

  The state of the cooling load is generally specified by detecting a temperature difference between an actual temperature and a predetermined temperature.

  In order to improve the cooling rate of the air in the refrigerator compartment, it is provided with means for circulating the air in the refrigerator compartment through the cooling surface of the heat storage material, more preferably through the first evaporator. preferable. Forced air cooling may be particularly desirable for display refrigerators where convection or conduction cooling may not be practical to obtain the cooling rate required to handle higher heat loads. Preferably, the means for circulating air has a fan. The air is preferably circulated out of the refrigerator compartment, passed through the cooling surface of the heat storage material, passed through the first evaporator, and returned to the refrigerator compartment.

  The refrigerator has a duct interposed between the wall of the refrigerator compartment and the outer heat insulating wall of the refrigerator. The heat storage material can be installed in the duct. In order to obtain the maximum surface area, it is preferable to install the heat storage material in the duct so that both outer sides of the heat storage material are in contact with the air flowing through the duct. That is, air passes through both sides of the heat storage material. In addition, the heat storage material is preferably formed in an elongated shape having a longitudinal axis parallel to the axis of the duct so that most of the surface area is exposed to the passing air.

  Preferably, the first evaporator is arranged downstream of the heat storage material, thereby increasing the cooling effect of the PCM to cool the air before passing through the first evaporator during the high cooling load period. Fully available.

  The vapor compression cooling system includes a compressor, a condenser, at least one expansion device, a first path through which the refrigerant flows into the first evaporator and returns to the compressor, and the refrigerant is the second. And a second path that circulates so as to flow into the evaporator and return to the compressor. In a preferred embodiment, the second path downstream of the second evaporator joins the first path upstream of the first evaporator.

  Control means for controlling the flow of refrigerant between the first evaporator and the second evaporator directs the refrigerant to both evaporators (at the same flow rate or different flow rates), or completely or In general, it can function to direct to one or the other evaporator.

Preferably, the control means for controlling the flow of the refrigerant to the first evaporator and the second evaporator according to the cooling load has a valve and a controller for switching the refrigerant path according to a change in the position state . Preferably, the controller controls the position of the valve according to the cooling load. As described above, a configuration in which the cooling load is confirmed by specifying the difference between the temperature of at least one of the air in the refrigerator compartment and the duct and the predetermined temperature is preferable. The temperature of at least one of the air in the refrigerator compartment and the duct is preferably specified by a temperature sensor.

  The controller is preferably configured to control the position of the valve in accordance with the composition ratio of the two phases of PCM.

  Also, in a preferred embodiment, the valve has only two position states: in the first position, the refrigerant is directed to both evaporators, and in the second position, the refrigerant is directed only to the first evaporator. Is done. That is, the valve is preferably a bistable valve. Thereby, a simplified control system can be configured.

  The controller is preferably configured to control the operation and speed of at least one of the operation of the compressor and the means for circulating the air.

  The PCM preferably contains water as a main component, which may further contain one or more solutes for adjusting the freezing point.

  The second evaporator can be configured to be partially or fully disposed within the PCM so that the PCM is cooled from the inside to the outside. The heat storage material preferably has a means for specifying the degree to which the state of the PCM is changing. This information can be used by the controller to control the flow of refrigerant to the second evaporator or to control the compressor.

In another aspect, the present invention provides a refrigerator having a refrigerating chamber for accommodating the object to be cooled, the refrigerator cools the refrigerating compartment during the refrigerating compartment is under relatively high cooling load A heat storage material containing a phase change material for cooling, a first evaporator through which a refrigerant flows to cool the refrigerator compartment, and cooling the phase change material when the refrigerator compartment is subjected to a relatively low cooling load And a vapor compression cooling system having a second evaporator through which the refrigerant circulates, and a control for controlling the flow of the refrigerant to the first evaporator and the second evaporator according to the cooling load applied to the refrigerator compartment Means.

According to the present invention, since the flow of the refrigerant is controlled according to the cooling load applied to the refrigerator compartment, the coolability of the refrigerator compartment can be improved by the first evaporator and the phase change material.

It is a partial schematic sectional side view of the refrigerated display cabinet by this invention. 1 is a schematic view of a refrigerant circuit according to the present invention. It is a partial schematic side view which shows a thermal storage material.

An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, refrigerated display cabinet comprises an insulated casing 1 having a glass door 2.

The heat insulating casing 1 is preferably composed of a vacuum formed heat insulating plate in combination with high density polyurethane for structural rigidity.

The glass door 2 can be double glass or preferably triple glass. In order to improve heat insulation, krypton gas may be provided between the glass plates.

The insulating casing 1 is mounted on a base that holds components of a vapor compression cooling system having a compressor 3, a condenser 4, and a condenser fan 5 associated with the condenser 4.

Cabinet has a compartment 6 as a refrigerating compartment, the product contained therein is cooled.

  The compartment 6 can be provided with illumination, and the illumination is preferably energy efficient LED illumination.

  The illumination power supply is preferably arranged outside the compartment 6. In order to further reduce the equipment heat load, an LED light source can also be placed outside the compartment 6 and light is guided into the compartment 6 by suitable means such as light guides, optical fibers and aerogels, etc. .

  Air is drawn from the compartment 6 into the duct 7 by the fan 7A for cooling.

  The duct 7 is partly defined by a gap between the inner wall 6A forming at least the compartment 6 and the inner wall of the insulating casing 1. The bottom of the compartment 6 may be defined by a first evaporator 10 (described below) or its casing.

  1 and 2 show a refrigerant circuit. The condensed refrigerant from the condenser 4 can selectively flow back to the compressor 3 along one of the two paths.

  The first path 8 carries the refrigerant through the first expansion device 9A and the first evaporator 10, which is typically a finned tube evaporator.

The second path 11 includes a second expansion device 9B and a second evaporator 12 incorporated in a heat storage unit 13 as a heat storage material for holding PC M1 4 as a phase change material, in this case water. Carry the refrigerant through.

The refrigerant flow is controlled by a valve 15 downstream of the condenser 4. Position state of the valve 15 is controlled by a controller 16 as control means, the controller 16, the compressor 3, the condenser fan 5, and is also used to control and fan 7A.

  As shown in FIGS. 1 and 2, the system is configured such that the refrigerant flowing out of the second evaporator 12 returns to the compressor 3 through the first evaporator 10. In addition, it can change suitably to other structures, such as two separate paths merge upstream of the compressor 3.

  Referring back to FIG. 1, the first evaporator 10 and the heat storage unit 13 both cool the air through which the air circulating through the duct 7 passes through the cooling surfaces of the heat storage unit 13 and the first evaporator 10. It is installed as follows.

  The temperature sensor 17 detects the temperature of the air exiting the compartment 6 and supplies a corresponding signal to the controller 16.

The first evaporator 10 is arranged downstream of the heat storage unit 13 so that the hottest warm air passes through the heat storage unit 13 and heat transfer from the PCM 14 to the warm air increases during the high cooling load period.

As shown in FIG. 3, the second evaporator 12 is incorporated in the heat storage unit 13, so that the solidification of the PCM 14 first occurs in the central region 14A, which is mainly ice, The outer side is an outer region 14C mainly made of water. The degree to which the PCM 14 is solidified or melted is detected by measuring the position of the interface 14B between ice and water. The measurement of the relative ratio of ice and water is performed by a sensor group 18 as sensors for measuring the conductivity of the PCM 14 at a point between the outer wall of the heat storage unit 13 and the evaporator 12.

Signal from the sensor group 1 8 receives the controller 16. Such a configuration is known in the technical field of heat storage materials incorporating PCM 14 .

To ensure the cooling surfaces exposed to air by the heat storage unit 13 within the duct 7 to the maximum, the heat storage unit 13, to allow passage of air on both sides in the width direction, from both walls 6A and insulation casing 1 They are spaced apart.

Returning to FIG. 1 and FIG. 2, the operation of the refrigerator will be described. When the refrigerator is operating in a steady state, i.e., when the temperature of the air flowing out of the compartment 6 is at or near a predetermined temperature, the controller 16 cools and solidifies the PCM 14 in the heat storage unit 13. The valve 15 is operated so that the refrigerant is pumped along the second path 11 through the second evaporator 12.

Also, once solidification of PCM 14 is detected by sensor 18, controller 16 can turn off or decelerate compressor 3 and condenser fan 5 to save energy. Typically, such compressors. 3 is either on or off, in some cases it is also possible to decelerate.

  By applying such control, in order to ensure sufficient solidification of the PCM 14 to obtain additional cooling during the next high cooling load period, the solidification state of the PCM 14 during steady operation is, for example, fully solidified. Control between 20% melting.

  If it is determined that the PCM 14 is sufficiently solidified during steady operation, the controller 16 can turn off or decelerate the compressor 3 to reduce energy consumption.

Furthermore, the controller 16 can control the operation or speed of the fan 7A during its steady state as a further way to regulate and control the compartment air temperature.

In a specific embodiment of steady operation, the refrigerant flows to both evaporators 10 and 12 and controls the product temperature by adjusting the temperature of the air exiting the compartment 6 .

  The air temperature is controlled by adjusting the speed of the fan 7A and switching the compressor 3 and the condenser fan 5 on and off.

Furthermore, when the amount of coagulated PCM 14 measured by the sensor 18 falls below a threshold value, the compressor 3 and the condenser fan 5 are operated.

  If the air temperature becomes too low, the fan 7A is decelerated.

When the PCM 14 is 100% solidified or nearly reached, the compressor 3 and the condenser fan 5 are stopped, and the air is cooled by the heat storage unit 13 or the PCM 14 .

The fan speed is accelerated as the air temperature rises, and when the further threshold temperature is reached, the compressor 3 and the condenser fan 5 are operated.

When the temperature sensor 17 detects that the temperature of the air from the compartment 6 is higher than a predetermined temperature (in some cases exceeding an allowable range from the predetermined temperature) during a period when the heat load is relatively high On the other hand, the controller 16 adjusts the valve 15 so that the refrigerant is preferentially guided to the first evaporator 10. As a result, the first evaporator 10 can obtain a larger cooling power for cooling the circulating air.

  The cooling load applied to the first evaporator 10 is also reduced by the cooling effect on the air by the heat storage unit 13 through which the air first passes.

  When it is detected that the temperature has dropped to or near a predetermined temperature, the controller 16 causes the refrigerant or a portion of its flow to be directed through the second evaporator 12 to re-solidify the PCM 14. The valve 15 is operated so that the steady state is finally reached.

It should be understood that many variations can be made to the above-described embodiments as appropriate without departing from the scope of the present invention as defined in the appended claims. For example, a refrigerator may include more than two evaporators. The temperature sensor 17 may instead be installed in the compartment 6.

As described above, the heat storage unit 13 can realize that the refrigerator continues cooling when a temporary power failure occurs. On the other hand, a battery may be provided for operation of the vapor compression system when a power failure occurs.

3 Compressor
6 Compartment as a cold room
7A fan
Ten First evaporator
12 Second evaporator
13 Thermal storage unit as thermal storage material
14 PCM as a phase change material
15 valve
16 Controller as control means
17 Temperature sensor
18 Sensor

Claims (11)

A refrigerator having a refrigerator compartment for accommodating a cooling object,
This refrigerator
A heat storage material having a phase change material;
A vapor compression cooling system having a first evaporator for cooling the refrigerator compartment and a second evaporator for cooling the phase change material;
Control means for controlling the flow of refrigerant to the first evaporator and the second evaporator according to the cooling load applied to the refrigerator,
When the refrigerator is subjected to a relatively low cooling load, the refrigerant flows into the second evaporator to cool the phase change material, and the refrigerator is subjected to a relatively high cooling load. The refrigerant flows into the first evaporator to provide the refrigerator with improved cooling performance due to the first evaporator and the phase change material. The refrigerator according to claim 1, wherein the refrigerant flows into both the first evaporator and the second evaporator when the refrigerator receives a relatively low cooling load. 3. The refrigerator according to claim 1, wherein when the refrigerator is subjected to a relatively high cooling load, the refrigerant generally flows only into the first evaporator. The control means for controlling the flow of the refrigerant includes a valve and a controller for controlling a position state of the valve in accordance with a cooling load applied to the refrigerator. The refrigerator described. The refrigerator according to claim 4, wherein the valve is a bistable valve. The refrigerator according to claim 4 or 5, wherein the cooling load applied to the refrigerator is determined by a temperature sensor for specifying a temperature of the refrigerator compartment. Having a sensor to identify the phase composition ratio of the phase change material;
The controller according to any one of claims 4 to 6, wherein the controller controls a position of the valve in accordance with a composition ratio of the phase of the phase change material. The vapor compression cooling system has a compressor,
The controller according to any one of claims 4 to 7, wherein the controller controls the amount of cooling provided to the refrigerator compartment by controlling the compressor. The refrigerator has a fan that circulates to the heat storage material and the first evaporator to cool the air from the refrigerator compartment,
The refrigerator according to any one of claims 4 to 8, wherein the controller controls the amount of cooling provided to the refrigerator compartment by controlling the operation or speed of the fan. The thermal storage material has two opposing cooling surfaces,
The refrigerator according to any one of claims 1 to 9, wherein air can flow through both sides of the heat storage material so as to pass along both of the cooling surfaces. The refrigerator according to claim 10, wherein the first evaporator is disposed downstream of the heat storage material.

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