Patent Application
20130098091
This section is intended to provide a background or context to the invention recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The present invention relates generally to the field of temperature-controlled display devices (e.g. refrigerated display devices or cases, etc.) having a temperature-controlled space for storing and displaying products such as refrigerated foods or other perishable objects. More specifically, the present invention relates to a refrigerated display case having an active evaporative condensate dissipation system for removing liquid condensate (i.e. melted frost or ice) from a cooling coil during or following a defrost mode of operation for the case. Still more specifically, the present invention relates to an active evaporative condensate dissipation system having multiple evaporative dissipation zones that operate on an as-needed basis and at successively higher temperatures for increasing an overall evaporative dissipation capability of the system.
It is well known to provide a temperature-controlled display device such as a refrigerator, freezer, refrigerated merchandiser, refrigerated display case, etc., that may be used in commercial, institutional, and residential applications for storing or displaying refrigerated or frozen objects. For example, it is known to provide service type refrigerated display cases for displaying fresh food products such as beef, pork, poultry, fish, etc. Such display cases typically have a closed front (e.g. with doors for accessing food products stored within the temperature-controlled space), or may have an open-front that uses a flow of chilled air that is discharged across the open front of the case to help maintain a desired temperature within the temperature-controlled space.
Such refrigerated cases typically include cooling elements (e.g. cooling coils, heat exchangers, evaporators, etc.) that receive a coolant (e.g. a liquid such as a glycol-water mixture, or a refrigerant, etc.) from a cooling system (such as a refrigeration system) during a cooling mode or operation to provide cooling to the temperature-controlled space. Oftentimes the cooling system operates to provide coolant to the cooling element at a temperature below 32° F., causing moisture from the air in the ambient environment to condense on the cooling element, and resulting in an accumulation of frost and/or ice on an exterior surface of the cooling element that is removed (e.g. melted) during a defrost mode or operation of the case. The melted frost and/or ice (e.g. liquid condensate, water, etc.) from the cooling coil is usually routed to a suitable drain at (or near) the case's location within a facility for disposal. In some cases, such as where a drain may not be conveniently accessible at the location of the refrigerated case, it may be necessary to allow the liquid condensate to accumulate in a suitable repository or receptacle. The repository may be configured for removal to permit manually disposing the liquid condensate (e.g. by pouring down a remote drain, etc.), or the repository may be configured to simply contain the liquid condensate until it dissipates by evaporation.
However, such known evaporative dissipation systems have a number of deficiencies. For example, such known systems tend to overflow or spill when the rate of liquid condensate generated from defrosting exceeds the rate at which the liquid condensate can dissipate (which is exacerbated as ambient humidity rises because more defrosting of the cooling element is required, but less of the condensate evaporates in the humid conditions).
Accordingly, it would be desirable to provide a refrigerated display device or case with an improved evaporative condensate dissipation system that overcomes these and other disadvantages.
One embodiment of the invention relates to a refrigerated case with an active evaporative condensate dissipation pan system with electric heat backup that is intended to efficiently remove melted condensate from the cooling element. The active evaporative condensate dissipation pan system with electric heat backup is intended to evaporate defrost water from refrigerated cases when no drain line is available. An active evaporative condensate dissipation pan system with electric heat backup includes three stages of evaporative dissipation, each having a receptacle (e.g. pan): a first water accumulation pan, a second water dissipation pan with hot gas heating, and a third backup assist pan with electric heating. With this multi-tier (or stage) pan system, condensate removal is more efficient and reduces or eliminates the need for the electric condensate evaporator to be energized while simultaneously assisting in transferring heat from the hot gas refrigerant from the compressor discharge to provide at least partial de-superheating in advance of the condenser. Each pan provides a progressive evaporative dissipation stage for the condensate removal process. In most applications, the electric pan will not operate under ‘standard’ conditions. If the case is subjected to a severe environment that could include high-humidity conditions, more condensate water may be produced by the cooling element and subsequently collected (as overflow from the first pan) in the second dissipation pan of the system. In the unlikely event that the first and second pans were not able to provide sufficient evaporative dissipation, the third electrical heating assist pan is available as a back-up to dissipate condensate water collected as overflow from the second pan.
Another embodiment of the invention relates to a refrigerated display device having a temperature-controlled space for storing and displaying products, and a refrigeration system operable in a cooling mode and a defrost mode. The refrigeration system has a compressor and a cooling element and circulates a refrigerant through the cooling element during the cooling mode to provide cooling to the temperature-controlled space. An evaporative condensate dissipation system receives condensate liquid from an external surface of the cooling coil during the defrost mode and dissipates the condensate liquid by evaporation. The condensate dissipation system includes a first receptacle having a first overflow device, which receives the liquid condensate from the cooling coil. A second receptacle has a second overflow device disposed lower than the first receptacle and which receives the liquid condensate from the first receptacle when the liquid condensate in the first receptacle reaches the first overflow device. The second receptacle includes a heat exchanger that receives hot gas refrigerant from the compressor for heating the liquid condensate. A third receptacle is disposed lower than the second receptacle and receive the liquid condensate from the second receptacle when the liquid condensate in the second receptacle reaches the second overflow device. The third receptacle has an electric heating element controlled by a switch. The first receptacle and the second receptacle and the third receptacle each comprise pans disposed in a substantially vertically-aligned relationship with one another. The first and second overflow devices may be standpipes and the switch may be a float switch. The first receptacle raises the temperature of its liquid condensate to a first temperature for a first evaporative dissipation, and the second receptacle raises the temperature of its liquid condensate to a second temperature, greater than the first temperature, for a second evaporative dissipation, and the third receptacle raises the temperature of its liquid condensate to a third temperature, greater than the second temperature, for a third evaporative dissipation. The evaporative condensate dissipation system is configured to be installed in the refrigerated display device as a unitary module. A fan may be included to increase at least one of the first evaporative dissipation, the second evaporative dissipation, and the third evaporative dissipation. The first receptacle may include fins disposed thereon.
According to a further embodiment, a refrigerated display device includes a temperature-controlled space storing and displaying products. A cooling system has a cooling coil operable in a cooling mode and a defrost mode, and circulates a coolant through the cooling coil during the cooling mode to provide cooling to the temperature-controlled space. An evaporative condensate dissipation system receives a condensate liquid from the cooling coil during the defrost mode and dissipates the condensate liquid by evaporation. The condensate dissipation system includes a first pan having a first overflow device, and that receives the liquid condensate from the cooling coil. A second pan has a second overflow device and a heat exchanger, and receives the liquid condensate from the first pan when the liquid condensate in the first pan reaches the first overflow device. A third pan receives the liquid condensate from the second pan when the liquid condensate in the second pan reaches the second overflow device. The third pan has a heating element controlled by a switch in response to a level of the liquid condensate in the third pan. The first pan and the second pan and the third pan are disposed in a substantially vertically-aligned relationship with one another, and the overflow devices comprise standpipes. The cooling system includes a compressor and the coolant comprises a refrigerant and the heat exchanger receives the refrigerant after being discharged from the compressor. The liquid condensate in the first pan is warmed to a first temperature by exposure to ambient conditions for a first evaporative dissipation. The liquid condensate in the second pan is warmed to a second temperature, greater than the first temperature, by exposure to the heat exchanger for a second evaporative dissipation. The liquid condensate in the third pan is warmed to a third temperature, greater than the second temperature, by exposure to the heating element for a third evaporative dissipation.
Exemplary embodiments will hereafter be described with reference to the accompanying drawings, wherein like numerals denote like elements.
Referring generally to the FIGURES, a refrigerated display device is shown having an evaporative condensate dissipation system for disposing of the liquid condensate (e.g. water) from the cooling element during the defrost mode, according to an exemplary embodiment. The evaporative condensate dissipation system includes a series of progressive stages that operate at successively higher temperatures to provide a cascading arrangement of evaporative dissipation of the liquid condensate. The first stage includes a first pan that receives the liquid condensate from the cooling coil and operates at an ambient first temperature to provide a first evaporative dissipation. Any overflow from the first pan is directed through a first standpipe to a second stage. The second stage includes a second pan that receives the liquid condensate from the first pan via the first standpipe, and is heated by hot gas refrigerant from the compressor discharge for second stage operation at a higher second temperature to provide a second evaporative dissipation. Any overflow from the second pan is directed through a second standpipe to a third stage. The third stage includes a third pan that receives the liquid condensate from the second pan via the second standpipe, and is heated by an electric heating element for third stage operation at a higher third temperature to provide a third evaporative dissipation. The pans are vertically configured for gravity feed through the successive stages, and use of the hot gas refrigerant as a second stage heat source improves the efficiency of the condenser in the refrigeration system. The use of a multi-stage, gravity-feed system that uses ambient heating and hot-gas waste heat (in the first two stages) is intended to provide a reliable and energy-efficient system that can be readily installed and easily deployed in almost any refrigerated case location. According to an alternative embodiment, the first stage including the first pan may be heated by condensed liquid refrigerant that is discharged from the condenser and routed through a heat exchanger associated with the first pan, so that water in the first pan receives an additional source of warming, and the liquid refrigerant from the condenser receives some subcooling to help improve the capacity of the refrigerant.
Referring now more particularly to
In some embodiments, the cooling element 22 operates at a temperature lower than 32° F., resulting in an accumulation of frost and/or ice on an external surface of the cooling element 22 during operation in the cooling mode. After a sufficient amount of frost and/or ice accumulates on the cooling element 22, the cooling element 22 operates in a defrost mode of operation, which provides sufficient heat to melt the accumulated frost and/or ice into a liquid condensate (e.g. water, etc.). The heat of defrosting may be provided by any suitable method, such as interrupting the cooling mode and allowing ambient temperature to melt the frost/ice, or use of electric heating elements, or use of hot gas refrigerant routed through the cooling element, etc. In some embodiments, a drain line is not available at the location of the case for convenient disposal of the liquid condensate that melted from the cooling element, and the evaporative condensate dissipation system 40 is used as an alternative way to dispose of the condensate. According to one embodiment, the evaporative condensate dissipation system 40 is packaged as a single unit that is readily installed (e.g. in a plug-and-play type manner) into the compartment 16 in a refrigerated case 10 that may be intended for use in an application without access to a suitable drain. The ability to readily install and remove the evaporative condensate dissipation system 40 from any case, permits the case to be quickly adapted for an intended application, or re-adapted to a changed application, without having to custom-design the case around the presence or absence of drainage capability.
Referring now more particularly to
The first stage of the system includes a first receptacle 42 (e.g. water accumulation pan) with a first overflow device 44 (e.g. shown for example as a standpipe, but could be a weir, etc. according to alternative embodiments) and is configured to receive the liquid condensate from the cooling coil 22, either directly (by being disposed beneath the cooling element 22), or indirectly (e.g. from a drain pan 30 and drain line 32, see
The second stage of the system 40 includes a second receptacle 48 (e.g. water dissipation pan) with a second overflow device 50, and is disposed at a lower elevation than the first receptacle 42 and receives the liquid condensate from the first receptacle 42 (e.g. by gravity) when a first level of the liquid condensate in the first receptacle 42 reaches the first overflow device 44, so that any overflow from the first receptacle 42 is captured by the second receptacle 48. According to the illustrated embodiment, the second receptacle 48 is substantially vertically-aligned beneath the first receptacle 42 to permit a compact packaging of the system's components and to permit gravity-feed of the liquid condensate from the first receptacle 42 to the second receptacle 48. However, in other embodiments, the second stage receptacle 48 may not be directly beneath the first stage receptacle 42. The second receptacle 48 also includes a heat exchanger 52 (e.g. a coil, fin-coil, tubing arrangement, or passages formed within the wall of a base of the pan, etc.) that receives a supply of hot gas refrigerant from the discharge line 28 of the compressor 24 as a source of heating for the second stage of system. Heat exchanger 52 may include tubing (e.g. flex hoses, etc.) with quick-connect couplings 53 to engage corresponding portions of the compressor discharge line 28. The hot gas refrigerant raises the temperature of the liquid condensate in the second receptacle 48 to a second stage temperature, and the hot gas refrigerant is then routed to the condenser (not shown) in a pre-cooled (or at least partially de-superheated) state which enhances overall efficiency of the refrigeration system. As the liquid condensate at the second stage approaches the second stage temperature (e.g. higher than the first stage temperature), a second evaporative dissipation occurs to dissipate the contained liquid condensate to the ambient atmosphere. In the event that the rate of collection of liquid condensate generation from the cooling element exceeds the first and second evaporative dissipation rates, the third stage of the system is available.
The third stage of the system includes a third receptacle 56 (e.g. electric back-up assist pan, etc.) disposed at a lower elevation than the second receptacle 48 and receives the liquid condensate from the second receptacle 48 when a second level of the liquid condensate in the second receptacle reaches the second overflow device 50, so that any overflow from the second receptacle 48 is captured by the third receptacle 56. According to the illustrated embodiment, the third receptacle 56 is substantially vertically-aligned beneath the first and second receptacles 42, 48 to permit a compact packaging of the system's components and to permit gravity-feed of the liquid condensate from the second receptacle 48 to the third receptacle 56. However, in other embodiments, the third stage receptacle 56 may be not be directly beneath the first or second stage receptacles 42, 48. The third stage receptacle includes a heating element 58 (e.g. electric heating element, etc.) as a source of heating for the third stage of system. The heating element 58 can be controlled (i.e. turned on/off, modulated, etc.) by a switch 60 (e.g. a float switch, level switch, sensor or the like) that is responsive to a certain level of liquid condensate in the third receptacle 56 (e.g. a level slightly above the heating element so that the heating element is energized only when it is submerged, etc.). As the liquid condensate at the third stage approaches the third stage temperature (e.g. higher than the second stage temperature), a third evaporative dissipation occurs to dissipate the contained liquid condensate to the ambient atmosphere.
Referring to
In order to further enhance the first, second and/or third evaporative dissipation rates, the system may include one or more fans disposed adjacent to the pans. For example, as shown in
According to any exemplary embodiment, a refrigerated display device has an evaporative condensate dissipation system for disposing the liquid condensate (e.g. water) generated by the cooling element during the defrost mode. The evaporative condensate dissipation system includes a series of progressive stages that operate at successively higher temperatures to provide a cascading arrangement of evaporative dissipation of the liquid condensate. The first stage includes a first pan that receives the liquid condensate from the cooling coil and operates at an ambient first temperature to provide a first evaporative dissipation. The first pan may also receive heating from condensed liquid refrigerant routed to/through the pan from the condenser. Any overflow from the first pan is directed through a first standpipe to a second stage. The second stage includes a second pan that receives the liquid condensate from the first pan via the first standpipe, and is heated by hot gas refrigerant from the compressor discharge for second stage operation at a higher second temperature to provide a second evaporative dissipation. Any overflow from the second pan is directed through a second standpipe to a third stage. The third stage includes a third pan that receives the liquid condensate from the second pan via the second standpipe, and is heated by an electric heating element for third stage operation at a higher third temperature to provide a third evaporative dissipation. The pans are vertically configured for gravity feed through the successive stages, and use of the hot gas refrigerant as a second stage heat source improves the efficiency of the condenser in the refrigeration system.
As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.
It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).
The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.
No claim element herein is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for.” Furthermore, no element, component or method step in the present disclosure is intended to be dedicated to the public, regardless of whether the element, component or method step is explicitly recited in the claims.
It is also important to note that the construction and arrangement of the refrigerated display device or case with an improved evaporative condensate dissipation system as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments of the present inventions have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter disclosed herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present invention as defined in the appended claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present inventions.
