WO2010068367A1

WO2010068367A1 - Open front display case with secondary air curtain

Info

Publication number: WO2010068367A1
Application number: PCT/US2009/064577
Authority: WO
Inventors: Mary D. Saroka
Original assignee: Hill Phoenix, Inc.
Priority date: 2008-12-10
Filing date: 2009-11-16
Publication date: 2010-06-17
Also published as: EP2361027A1; EP2361027A4; EP2361027B1; CN102245059B; CN102245059A

Abstract

A refrigerated case has a base and a refrigerated compartment above the base. A rear wall and a top are along the refrigerated compartment. A refrigeration system includes a heat absorption heat exchanger and a first fan. The first fan is positioned to drive an airflow from a first inlet across the heat absorption heat exchanger. A first portion of the airflow passes through the rear wall and top to exit a first outlet. A second fan is positioned to drive a second airflow from a second inlet to exit a second outlet. The second airflow bypasses the heat absorption heat exchanger. A diversion port is positioned to direct a second portion of the first airflow to merge with the second airflow upstream of the second outlet.

Description

OPEN FRONT DISPLAY CASE WITH SECONDARYAIR CURTAIN

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present Application claims the benefit of priority under 35 U.S. C. § 119(e)(l) to co-pending U.S. Provisional Patent Application No. 61/121,408 titled "Open Front Display Case With Secondary Air Curtain" filed on December 10, 2008, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

[0002] The disclosure relates to refrigerated cases. More particularly, the disclosure relates to open front cases/merchandisers.

[0003] There are many varieties of refrigerated cases. Self-service cases exist for consumers principally to access product. A variety of self-service refrigerated case configurations exist, including: open front cases; open top cases; sliding front door cases; and hinged front door cases. In open front cases, a curtain flow of refrigerated air passes downward along the opening. A portion of the curtain flow returns to an inlet/return proximate the bottom of the opening along with some volume of entrained ambient air.

[0004] U.S. Patent No. 6,722,149 titled "Refrigerated Display Merchandiser" discloses an open front case wherein a secondary air curtain flow of ambient air is passed downward in front of the refrigerated curtain flow. The use of a secondary curtain flow may encourage a greater proportion of the refrigerated curtain flow to recirculate and with a reduced heat transfer to the recirculated portion of the refrigerated curtain flow from the ambient air. U.S. Patent No. 7,162,882 titled "Multi-Band Air Curtain Separation Barrier" discloses an open front case having two secondary air curtains. A first secondary air curtain passes downward in front of the refrigerated air curtain and is formed by a return airflow drawn from in front of the inlet/return. A second secondary air curtain flow of ambient air is directed across the opening in front of the first secondary flow. The first secondary flow can thus be somewhat cooler than the second secondary flow and yet further reduce heat transfer to the return flow. The disclosures of U.S. Patent No. 6,722,149 and U.S. Patent No. 7,162,882 are incorporated by reference in their entireties herein as if set forth at length.

SUMMARY

[0005] One aspect of the disclosure is a refrigerated case having a base. A refrigerated compartment is above the base. A rear wall and a top are along the refrigerated compartment. A refrigeration system includes a heat absorption heat exchanger and a first fan. The first fan is positioned to drive an airflow from a first inlet across the heat absorption heat exchanger. A first portion of the airflow passes through the rear wall and top to exit a first outlet. A second fan is positioned to drive a second airflow from a second inlet to exit a second outlet. The second airflow bypasses the heat absorption heat exchanger. A diversion port is positioned to direct a second portion of the first airflow to merge with the second airflow upstream of the second outlet.

[0006] In various implementations, the heat absorption heat exchanger and first fan may be in the base.

[0007] The case may be implemented as a reengineering of an existing case configuration or a remanufacturing of an existing case.

[0008] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a schematic representation of a perspective view of a refrigerated case according to an exemplary embodiment.

[0010] FIG. 2 is a schematic representation of a side sectional view of the case according to the embodiment of FIG. 1.

[0011] FIG. 3 is a schematic representation of a sectional view of a prior art case top.

[0012] FIG. 4 is a schematic representation of a sectional view of a first top for the case according to the embodiment of FIG. 1.

[0013] FIG. 5 is a schematic representation of a sectional view of a second top for the case according to the embodiment of FIG. 1.

[0014] FIG. 6 is a graphical representation of a percentage of the primary airflow diverted to velocity ratio according to an exemplary embodiment.

[0015] FIG. 7 is a graphical representation of mixed temperature and relative humidity to percentage of primary airflow diverted according to an exemplary embodiment.

[0016] FIG. 8 is a graphical representation of load reduction and secondary airflow temperature reduction to percentage of primary airflow diverted according to an exemplary embodiment.

[0017] Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0018] FIG. 1 shows a refrigerated case 20. The case 20 (see also FIG. 2) extends from a first (e.g., left as viewed by a consumer facing the case) end 22 to a second (right) end 24. The case has a front 26 and a rear 28. The exemplary front 26 has an opening 30 to a refrigerated compartment 32. The opening may extend from an upper end 34 proximate a top 36 to a lower end 38 proximate a base 40 below the compartment. The base 40 may contain portions of the refrigeration equipment (discussed below). [0019] FIG. 2 shows the compartment 32 in front of the front surface 42 of a rear wall structure 44. The rear wall structure 44 includes a rear duct 46 section. The exemplary compartment 32 is also below a lower surface 48 of a top/upper wall structure 50 which contains a top duct section 52. The top duct section 52 extends from a junction with the upper end of the rear duct section 46. The compartment 32 contains a vertical array of shelves 60. Each exemplary shelf 60 extends from a rear end/edge 62 at the rear wall 44 to a front end/edge 64. Each exemplary shelf 60 has an upper surface 66 which may support refrigerated products 68 (e.g., food, beverages, and the like).

[0020] In one example, the refrigeration system's compressor 70 and heat rejection heat exchanger (e.g., gas cooler or condenser) 72 may be located in the case base 40. A fan (not shown) may force an airflow across the condenser 72. Alternative implementations may involve one or more of the refrigeration system components being remote. For example, a single remote central compressor and condenser may deliver refrigerant to multiple display cases.

[0021] The expansion device 76 and heat absorption heat exchanger (e.g., evaporator) 78 may also be located in the base 40. A fan 80 may be in the base 40 to drive a recirculating airflow 500 along a flowpath 510. The airflow 500 enters the base at an inlet/return 82 proximate the lower end 38 of the opening 30. As the airflow 500 passes upward through the rear duct section 46, portions 502 may be vented into the compartment as branch flows to flow over/around the product 68 to cool the product. The remainder of the flow 500 reaches the top duct section 52.

[0022] In the prior art, the air flow generally passes along a first leg 510-1 of the flowpath 510 within the base and through the evaporator 78 so as to be cooled. The airflow 500 then flows upward through the rear duct section 46 along a second leg 510-2. Minus the branch flows 502 (if any) the airflow 500 then flows forward (as shown in FIG. 3) along a third leg 510-3 through the top duct section 52. The flow is discharged from an outlet 90 (e.g., as a discharge flow 504). Upon discharge, the flow 504 may interact/communicate with the secondary curtain flow 506. The secondary curtain flow 506 is discharged from a second outlet 92 immediately ahead/forward of the outlet 90. The outlet 92 is immediately behind a header 94 (e.g., containing lights 96). The secondary curtain flow 506 is provided by a secondary airflow 508 driven through a secondary duct 100 by a second fan 102. The exemplary secondary duct 100 is formed as part of the case top structure 50 above the top duct section 52. The exemplary secondary duct 100 and associated flowpath have an inlet 104. The inlet 104 is proximate the rear of the case top.

[0023] FIG. 4 shows a modified case top according to one exemplary embodiment based upon the baseline version of FIG. 3. In the top duct section, the flow 500 is further split by a baffle 106 into a first portion 512 (along a first branch 520) which passes out the outlet 90 as a refrigerated air curtain 504'. A second portion 514 is diverted (along a second branch or passageway 522) to merge with the secondary airflow 508 to form the secondary air curtain/flow 506' (to precool the secondary air curtain flow relative to the flow 508). Because the airflow 500 is refrigerated, the secondary curtain/flow 506' will be colder than the prior art secondary curtain/flow 506. The exemplary flow 514 is introduced to the flow 508 via an opening/port 120 (diversion port) upstream of the outlet 92. A deflector 122 may be positioned to help block the flow 508 from flowing into the passageway 522. The exemplary deflector extends downward from an upper edge of the port 120 that may be formed of a non-metal or other relatively insulative material so as to limit opportunities for condensation on the deflector due to the temperature differences between the flow 508 on one side and the flow 514 on the other side.

[0024] FIG. 5 shows a top 202 of a case 200 which, except as otherwise described, may be similar to the case 20. The baffle 204 is oriented or otherwise configured to converge the branch 522' toward the port 206. The convergence increases the speed of the flow 514' exiting the outlet 206 relative to the flow 514. This increased speed causes increased mixing potentially resulting in a more uniform flow 506" relative to the FIG. 4 flow 506'. The increased speed is also intended to reduce the chance of flow reversal through the branch/passageway 522'. [0025] In one example, the FIG. 3 prior art flow 504 discharges at a temperature of 34°F (1.1°C) and relative humidity of 90%; the flow 506 discharges at the ambient temperature of 75°F (23.9°C) and 55% relative humidity. In the revised exemplary case of FIGS. 4 or 5, sufficient airflow 514/514' is mixed with the airflow 508 so that the discharged airflow 506/506" has a temperature of approximately 67°F (19.4°C) and a relative humidity of 64%.

[0026] In the graphical representation of FIG 6, the vertical axis represents the percentage of the airflow 500 that is diverted and mixed with the secondary airflow 508 to produce the pre-cooled secondary airflow 5067506" for different airflow ratios shown on the horizontal axis. The airflow ratio is defined as the ratio of the mixed secondary air curtain/flow 506/506" average velocity to the refrigerated air curtain/flow 5047504" average velocity and different ratios are obtained depending upon the airflow volumetric flow rates and opening widths (outlet areas). Exemplary rates of the total primary airflow 500 and secondary airflow 508 are near parity (e.g., the airflow 500 is between half and twice the airflow 508, more narrowly, 80-120%). In the FIG. 6 example, the primary and secondary opening widths are the same while the total primary airflow 500 is 8% less than the secondary airflow 508. Thermodynamics requires that both mass and energy be conserved as the diverted flow at 34°F (1.1°C) and relative humidity of 90% is mixed with airflow 508 at an ambient temperature of 75°F (23.9°C) and 55% relative humidity.

[0027] FIG. 7 shows the impact to the mixed secondary airflow 5067506" temperature and relative humidity for the percent (%) of diverted airflow shown in FIG 6.

[0028] The left side vertical axis of FIG. 8 shows infiltration and total cooling load reductions of a secondary air curtain operating with the temperature and moisture levels of FIG 7. While the presence of a secondary air curtain will reduce the amount of interface shearing/mixing between the primary air curtain and the secondary air curtain, this interaction is not entirely eliminated. By pre-cooling the secondary air curtain, the temperature difference between the primary air curtain and the secondary air curtain is reduced and for the same shearing/mixing, less infiltration will occur. The FIG. 8 right side vertical axis shows the secondary air curtain temperature reduction for the percent (%) of diverted flow of FIGS. 6 and 7.

[0029] Exemplary diversions from the flow 500 are effective to divert the flow 514/514' as approximately 5-40% (more narrowly 15-25%) of the remainder of the flow 500 reaching the baffle 106/204 or 1-12% (more narrowly 3-10% or 4-7%) of the initial flow 500 through the heat absorption heat exchanger. The exemplary flow 514/514' is effective to reduce the temperature of the secondary curtain flow 5067506" at least approximately 2°F (1.1°C) below the temperature of the flow 508 (more narrowly 5°F-8°F (2.8°C-4.4°C)).

[0030] One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, the present teachings may be implemented in the context of a remanufacturing or reengineering of a variety of existing or yet-developed cases and configurations thereof. Accordingly, other embodiments are within the scope of the following claims.

[0031] It is also important to note that the construction and arrangement of the elements of the refrigerated case with secondary air curtain as shown in the preferred and other 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 recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the plenum and its inlets, outlets, and airflow devices may be arranged in any suitable manner or otherwise varied. The length or width of the structures and/or members or connectors or other elements of the case may be varied. It should be noted that the elements and/or assemblies of the refrigerated case may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures and combinations. Accordingly, all such modifications are intended to be included within the scope of the appended claims. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the appended claims.

[0032] The order or sequence of any process or method steps may be varied or re- sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A refrigerated case, comprising: a base; a refrigerated compartment above the base; a rear wall along the refrigerated compartment; a top along the refrigerated compartment; a refrigeration system comprising: a heat absorption heat exchanger; and a first fan positioned to drive a first airflow from a first inlet across the heat absorption heat exchanger, at least a first portion of the first airflow passing through the rear wall and top to exit a first outlet; and a second fan positioned to drive a second airflow from a second inlet to exit a second outlet bypassing the heat absorption heat exchanger, wherein: a diversion port is positioned to direct a second portion of the first airflow to merge with the second airflow upstream of the second outlet.

2. The case of claim 1 wherein the first outlet and the second outlet are positioned so as to produce adjacent first and second air curtains, portions of both of which return to the first inlet to become the airflow.

3. The case of claim 1 wherein the diversion port is dimensioned to pass approximately 1-12 percent of the first airflow as the second portion.

4. The case of claim 1 wherein the first outlet is proximate an upper front of the refrigerated compartment; and the second outlet is immediately forward of the first outlet.

5. The case of claim 4 wherein a diversion passageway tapers in cross-section toward the diversion port at which the second portion of the first airflow is merged with the second airflow.

6. The case of claim 1 further comprising at least one vertical array of shelves.

7. The case of claim 1 wherein a portion of the airflow downstream of the heat absorption heat exchanger is diverted into the refrigerated compartment along a rear of the refrigerated compartment.

8. A method for operating the case of claim 1 , the method comprising: driving the first airflow by the first fan; driving the second airflow by the second fan; and diverting said second portion as approximately 1-12 percent of the first airflow to merge with the second airflow upstream of the second outlet.

9. The method of claim 8 wherein the diverting is effective to reduce a temperature of the second airflow by at least approximately 1.1 degrees C proximate the second outlet.

10. The method of claim 9 wherein the diverting is effective to reduce the temperature of the second airflow by approximately 2.8-4.4 degrees C proximate the second outlet.

11. A refrigerated case comprising: a base; a refrigerated compartment above the base; a rear wall along the refrigerated compartment, the rear wall including a rear duct; a top along the refrigerated compartment, the top including a top duct; a refrigeration system comprising: a heat absorption heat exchanger; and a first fan positioned to drive a first airflow from a first inlet across the heat absorption heat exchanger, at least a first portion of the first airflow passing through the rear duct and the top duct to exit a first outlet, the first portion of the first airflow at least partially creating a primary air curtain; and a second fan positioned to drive a second airflow from a second inlet to exit a second outlet bypassing the heat absorption heat exchanger, the second airflow at least partially creating a secondary air curtain; and a baffle disposed within the top duct; the baffle positioned to direct the first portion of the first airflow to the first outlet and to direct a second portion of the first airflow to the second outlet for precooling the secondary air curtain.

12. The case of claim 11 wherein a flow passage between the baffle and the top duct converges toward the second outlet to accelerate the second portion of the first airflow.

13. The case of claim 12 further comprising a deflector coupled to the top duct and positioned to direct the second portion of the first airflow downwardly toward the second outlet.

14. The case of claim 13 wherein at least one third portion of the first airflow is diverted from the rear duct into the refrigerated compartment.

15. A method for operating an open-front refrigerated case, the method comprising: directing a first airflow through a heat absorption heat exchanger to cool the first airflow; directing a first portion of the first airflow as a first air curtain flow across an opening of the refrigerated case; directing a second airflow; diverting a second portion of the first airflow to merge with the additional airflow; discharging the combined second airflow and the second portion of the first airflow in front of the first air curtain flow as a second curtain flow; and returning at least portions of the first air curtain flow and the second air curtain flow as the first airflow through the heat absorption heat exchanger.

16. The method of claim 15 wherein the diverting is effective to reduce a temperature of the second airflow by approximately 2.8-4.4 degrees C.

17. The method of claim 15 wherein the diverting is effective to reduce a temperature of the second airflow by at least approximately 1.1 degrees C.

18. The method of claim 12 wherein the second portion of the first air flow is approximately 1-12 percent of the first airflow at the point of diversion; and the second portion of the first airflow is approximately 1-11 percent of the second airflow.

19. The method of claim 12 wherein the second portion of the first airflow is approximately 4-7 percent of the first airflow at the point of diversion; and the second portion of the first airflow is approximately 4-7 percent of the second airflow.