Patent Application
20180084925
Various exemplary embodiments relate to a refrigeration system for a merchandiser.
Refrigeration systems are well known and widely used in supermarkets, warehouses, and other environments to refrigerate product. Conventional refrigeration systems typically include an evaporator, a compressor, and a condenser. Some merchandiser refrigeration systems are utilized to refrigerate product (e.g., meat, fish, deli product, etc.) that is sensitive to airflow. For example, existing meat and deli merchandisers typically use a linear serpentine coil that is placed at the bottom of the product display area and that conductively cools a platform (often formed of metal) on which product is supported. One difficulty with refrigeration systems using a standard serpentine coil is that it is difficult to keep a uniform surface temperature just above freezing so that the displayed products can be kept fresh for longer periods of time while also reducing the need to defrost.
An exemplary embodiment includes a refrigerated merchandiser having a case including a base and a canopy at least partially defining a product display area. A eutectic plate is positioned in the product display area and includes a housing defining a hollow cavity. A fluid is contained in the housing. A heat exchanger including a coil is positioned in the housing to cool the fluid. The coil has an inlet, an outlet spaced from the inlet, a first portion, and a second portion adjacent and in thermal communication with the first portion to define a tube-to-tube heat exchanger.
Another exemplary embodiment includes a case, a eutectic deck plate, and a eutectic shelf plate. The case includes a base and a canopy at least partially defining a product display area. The eutectic deck plate is positioned above the base and includes a first housing defining a hollow cavity, a first fluid contained in the first housing, and a first heat exchanger including a first coil positioned in the first housing to cool the first fluid. The first coil has a first inlet extending from the first housing, a first outlet extending from the first housing, a first portion, and a second portion adjacent and in thermal communication with the first portion to define a first tube-to-tube heat exchanger. The eutectic shelf plate is positioned above the deck plate and includes a second housing defining a hollow cavity, a second fluid contained in the second housing, and a second heat exchanger including a second coil positioned in the second housing to cool the second fluid. The second coil has a second inlet extending from the second housing, a second outlet extending from the second housing, a third portion, and a fourth portion adjacent and in thermal communication with the third portion to define a second tube-to-tube heat exchanger.
According to another exemplary embodiment, a refrigeration system for cooling a refrigerated merchandiser includes a case containing a eutectic plate positioned in a product display area and a temperature sensor connected to the eutectic plate. The eutectic plate includes a housing defining a hollow cavity. A fluid is contained in the housing and a heat exchanger including a coil is positioned in the housing to cool the fluid. The coil includes an inlet, an outlet spaced from the inlet, a first portion, and a second portion adjacent and in thermal communication with the first portion to define a tube-to-tube heat exchanger. The temperature sensor is positioned proximate the inlet and outlet. A refrigeration system circulates a refrigerant through the heat exchanger. A controller is in communication with the temperature sensor and the refrigeration system. The controller is configured to activate the refrigeration system in response to a first temperature signal and deactivate the refrigeration system in response to a second temperature signal.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
The case 12 has a base 16 and a top wall or canopy 18 that is attached to the base 16 and cantilevered over the product display area 14 via uprights 20. One or more first glass panels 22 are coupled to a rear of the case 12 between the uprights 20 to enclose the rear side of the merchandiser 10. The first glass panels 22 can be fixed to the uprights 20, or the first set of glass panels 22 can move relative to the uprights 20 (e.g., as part of one or more doors) to selectively provide access to the product display area 14 from the rear of the case 12. One or more second glass panels 24 are positioned adjacent a front edge of the case 12 to enclose the front side of the merchandiser 10. As illustrated, the second glass panels 24 (two shown) are attached to a front of the base 16 and a front of the canopy 18. The second glass panels 24 can be fixed in place (i.e. not movable), or the second glass panels 24 can move relative to the base 16 and the canopy 18 (e.g., as part of one or more moveable doors) to selectively provide access to the product display area 14 from the front of the case 12. In some embodiments, the first or second glass panels 22, 24 can be removed to provide an open-rear or open-front of the merchandiser 10.
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In the tube-to-tube heat exchanger region 49, the first portion 44A and the second portion 44B of the coil 44 can be fused together, in contact (e.g. surface-to-surface engagement), or otherwise spaced close enough to provide heat transfer between the coil portions. The tube-to-tube heat exchanger region 49 limits temperature fluctuations in the deck plate 28, for example, by reducing or eliminating a hot or warm spot at or near the outlet 48. This results in a more uniform temperature profile across the surface of the deck plate 28 and temperature stability within the deck plate 28. In some embodiments, the heat exchanger can include more than one tube-to-tube heat exchanger region 49. It will be appreciated that other coil configurations can also be used and the location and configuration of the tube-to-tube heat exchanger region 49 can be modified.
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The first and second brackets 54, 58 support a shelf plate 62. According to an exemplary embodiment, the shelf plate 62 defines a eutectic plate that has a housing 63 with a top wall 64, a bottom wall 66, a front wall 68, a rear wall 70, and a pair of side walls 72. The top and bottom walls 64, 66 meet the front and rear walls 68, 70, and the side walls 72 at substantially flush right angles without any overhang or flanges extending beyond the front and rear walls 68, 70, and the side walls 72.
The shelf plate 62 housing 63 has a hollow cavity 74 that contains a fluid 76. The fluid 76 can be homogenous, such as water, or a refrigerant solution or mixture. The fluid 76 is cooled to a specific temperature (e.g., frozen or unfrozen) and, after reaching the desired temperature, provides cooling directly to the product placed on or near the shelf plate 62. The amount of fluid 74 contained in the housing is such that the fluid 74 fills the cavity 74 when the fluid is at or approximately at the desired temperature for the shelf plate 62. For example, for a fluid 76 intended to be frozen (e.g., water), the housing 63 is initially filled with fluid 76 to a level that is less than the total volume of the cavity 74 so that the fluid 76 can expand to fill all or approximately all of the entire empty volume of the housing. In an exemplary embodiment, the fluid 76 is water that is filled to approximately 93% of the empty volume of the housing 63.
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In the tube-to-tube heat exchanger region 83, the first portion 78A and the second portion 78B of the coil 78 can be fused together, in contact (e.g. surface-to-surface engagement), or otherwise spaced close enough to provide heat transfer between the coil portions. The tube-to-tube heat exchanger region 83 limits temperature fluctuations in the shelf plate 62, for example, by reducing or eliminating a hot or warm spot at or near the outlet 82. This results in a more uniform temperature profile across the surface of the shelf plate 62 and temperature stability within the shelf plate 62. In some embodiments, the heat exchanger can include more than one tube-to-tube heat exchanger region 83. It will be appreciated that other coil configurations can also be used and the location and configuration of the tube-to-tube heat exchanger region 83 can be modified.
According to various exemplary embodiments, each of the eutectic deck plates 28 and eutectic shelf plate 62 is regulated to maintain an outer surface temperature that is slightly above freezing, which helps reduce or prevent the need to defrost the plates while maintaining a suitable temperature to keep products (e.g., food) fresh. For example, the average temperature across an outer surface of each of the plates 28, 62 can be maintained in the range of approximately 32° F. to 34° F. The plates 28, 62 are cooled or refrigerated to a desired temperature via the respective heat exchangers to maintain the desired temperature range across the plates 28, 62. During a non-refrigeration phase (i.e. when no cooling or refrigeration is applied by the heat exchanger to the fluid in the plate), the temperature spread, or the difference in temperature across different regions of each the plates 28, 62 (i.e. temperature gradient across the surface of the each of the plates 28, 62) is maintained at approximately 4° F. or less for a period of time. The period of time can be two hours, five hours, ten hours, twelve hours, or, in certain conditions, 24 hours.
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In the manual cooling mode, the deck plate 28 and the shelf plate 62 are connected to a refrigeration system, for example using quick connect/disconnect lines and one or more shutoff valves. The refrigeration components 86 circulate refrigerant through the heat exchangers 44, 78 and the deck plate fluid 42 and shelf plate fluid 74 are cooled, for example until the fluids 42, 74 are frozen solid, and the flow of refrigerant is stopped. For example, the cooling system 80 can operate overnight (e.g., during times of low merchandiser engagement by a consumer or retail personnel) to freeze the fluids 42, 74. After the fluid has frozen or otherwise reached the desired temperature range, the cooling system 80 can be disconnected and the merchandiser 10 can be moved to a desired location that is remote from the cooling system 80. As the frozen fluid thaws, the deck plate 28 and the shelf plate 62 are kept cool via heat exchange between the fluid, the upper surfaces of the plates 28, 62, and the product supported on the plates 28, 62. Depending on the conditions surrounding and in the merchandiser 10, the plates can keep a desired temperature profile for up to, for example, 24 hours. In an exemplary embodiment, the fluid can remain solid for approximately 10-12 hours in Type I conditions (approximately 75° F. and approximately 55% relative humidity).
In the automatic mode, the deck plate 28 and shelf plate 62 remain connected to the cooling system 80 and the refrigerant flow to the deck plate 28 and the shelf plate 62 is turned on or off as needed by a control system 82.
A second temperature sensor 90 is connected to the shelf plate 62. The second temperature sensor 90 can be positioned on the bottom wall 66 of the shelf plate 62 proximate the cooling component outlet 76. For example, as shown in
The temperature sensors 88, 90 communicate with a controller 94 that is configured to start and stop the flow of refrigerant through the deck plate 28 and the shelf plate 62. The controller 94 can be incorporated into the merchandiser 10 or positioned remotely from the merchandiser 10. One example of a controller 94 is the SafeNet III controller provided by Hussmann. The temperature sensors 88, 90 monitor the respective surface temperatures of the deck plate 28 and the shelf plate 62, and the controller 94 turns the cooling system on or off to prevent frost buildup on the plates and to reduce or eliminate the need to defrost the merchandiser 10 while avoiding undesirably high product temperatures that would otherwise result from a lack of cooling from the plates 28, 62. In an exemplary embodiment, the supply of refrigerant to the deck plate 28 is initiated at approximately 33° F. and shut off at approximately 28° F., and the supply of refrigerant to the shelf plate 62 is initiated at approximately 35° F. and shut off at approximately 29° F.
As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the exemplary embodiments of the present disclosure, and are not intended to limit the structure of the exemplary embodiments of the present disclosure to any particular position or orientation. Terms of degree, such as “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of the given value, for example, general tolerances associated with manufacturing, assembly, and use of the described embodiments.
Various features and advantages of the invention are set forth in the following claims.
