WO2011100011A1

WO2011100011A1 - Refrigerated case defrost water evaporation

Info

Publication number: WO2011100011A1
Application number: PCT/US2010/057579
Authority: WO
Inventors: Markus Schu; Sri NUGROHO
Original assignee: Carrier Corporation
Priority date: 2010-02-09
Filing date: 2010-11-22
Publication date: 2011-08-18
Also published as: PL2373200T3; EP2373200B1; CN102740741A; EP2373200A1; CN102740741B

Abstract

A refrigerated case has a body. The body has a refrigerated compartment and an air flowpath extending from an inlet positioned to receive air from the compartment to an outlet positioned to discharge air to the compartment. The body has a drain. A vessel is positioned to receive water discharged from the drain. The refrigerant air heat exchanger is along a refrigerant flowpath and within the air flowpath. The vessel was supported to move between a lowered position and a raised position. At least one spring is coupled to the vessel to bias the vessel from the lowered position toward the raised position.

Description

REFRIGERATED CASE DEFROST WATER EVAPORATION

CROSS-REFERENCE TO RELATED APPLICATION

[0001] Benefit is claimed of U.S. Patent Application Ser. No. 61/302,733, filed February 9, 2010, and entitled "Refrigerated Case Defrost Water Evaporation", the disclosure of which is incorporated by reference herein in its entirety as if set forth at length.

BACKGROUND

[0002] The disclosure relates to refrigerated cases. More particularly, the disclosure relates to evaporation of defrost water.

[0003] Refrigerated cases typically feature an evaporator along a recirculating air flowpath to/from the refrigerated compartment of the case. Water from the air condenses on the evaporator and may freeze. Resulting frost may accumulate on the evaporator and may, in turn, block the airflow. Accordingly, from time to time, a defrost mode is initiated. Exemplary defrost modes may include use of an external heating element (e.g., an electric resistance element) to heat the evaporator and melt the frost. Alternatively, warm refrigerant may be used (e.g., via running the compressor in reverse or using multi-way valves to direct warm refrigerant to the evaporator (which may then function as a condenser or gas cooler in such a defrost mode)).

[0004] The defrost operation produces melt water which may pass to a drain and be collected in a pan or other vessel. The melt water, in turn, is then encouraged to evaporate by heating (e.g., by exposure to warm refrigerant). Evaporation may further be facilitated via partial immersion of sponge elements in the accumulation in the vessel. The sponge elements wick water out of the vessel and expose them to air along a large surface area.

SUMMARY

[0005] One aspect of the disclosure involves a refrigerated case comprising a body. The body has a refrigerated compartment and an air flowpath extending from an inlet positioned to receive air from the compartment to an outlet positioned to discharge air to the compartment. The body has a drain. A vessel is positioned to receive water discharged from the drain. The refrigerant-air heat exchanger is along a refrigerant flowpath and within the air flowpath. The vessel was supported to move between a lowered position and a raised position. At least one spring is coupled to the vessel to bias the vessel from the lowered position toward the raised position. [0006] In various implementations, the vessel may have a plurality of compartments including: a first compartment positioned to receive said water from the drain; and at least one additional compartment positioned to receive overflow from the first compartment.

[0007] Other aspects involve a method for using such a case. A case is operated in a cooling mode wherein refrigerant is delivered to the refrigerant-air heat exchanger along the refrigerant flowpath to cool air along the air flowpath, causing condensate from the air flowpath to freeze onto the refrigerant-air heat exchanger. The case is operated in a defrost mode wherein the ice is melted, causing the melted ice to flow to the drain and be discharged from the drain as said water. Receipt of the water by the vessel increases an accumulation within the vessel and causes the vessel to descend.

[0008] Another aspect of the disclosure involves a refrigerated case comprising a body. The body has a refrigerated compartment and an air flowpath extending from an inlet positioned to receive air from the compartment to an outlet positioned to discharge air to the compartment. The body has a drain. A vessel positioned to receive water discharged from the drain. The refrigerant-air heat exchanger is along the refrigerant flowpath and within the air flowpath. The vessel has a plurality of compartments including: a first compartment positioned to receive said water from the drain; and at least one additional compartment positioned to receive overflow from the first compartment. A refrigerant line passes through the first compartment and the at least one additional compartment.

[0009] 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

[0010] FIG. 1 is a simplified view of a refrigerated case.

[0011] FIG. 2 is a simplified vertical front-to-back sectional view of the case of FIG. 1.

[0012] FIG. 3 is a schematic view of a refrigeration system of the case of FIG. 1.

[0013] FIG. 4 is a schematic top view of an evaporation pan of the case of FIG. 1.

[0014] FIG. 5 is a simplified vertical sectional view of the pan of FIG. 4 in a relatively unfilled state.

[0015] FIG. 6 is a view of the pan of FIG. 5 in an intermediate fill state.

[0016] FIG. 7 is a view of the pan of FIG. 5 in a relatively filled state. [0017] Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0018] FIGS. 1 and 2 show a refrigerated case 20 having a body 22 at least partially enclosing a refrigerated compartment (interior) 24. The exemplary case/body is an open- front case having a left wall 26 at a left side 28, a right wall 30 at a right side 32, a top panel (wall) 34 at a top 36, a base 38 at a bottom 40, and a rear (back) panel 42 at a back (rear end) 44. An opening 46 extends at least partially along a front of 48 of the case. In the exemplary case, a vertical array of shelves 50 is positioned within the compartment 24.

[0019] The exemplary case 20 includes a refrigeration system 60 (FIG. 3). The refrigeration system comprises a compressor 62 along a refrigerant flowpath 64. The compressor has an inlet (suction port) 66 and an outlet (discharge port) 68. The refrigeration system includes a first refrigerant-air heat exchanger 70 and a second refrigerant-air heat exchanger 72. An expansion device 74 may be along the refrigerant flowpath 64 between the heat exchangers 70 and 72 opposite the compressor. Fans 80 and 82 may respectively drive airflows 84 and 86 across the heat exchangers 70 and 72.

[0020] In a cooling mode of operation, refrigerant compressed by the compressor exits the outlet 68 and proceeds to the first heat exchanger 70 which acts as a condenser or gas cooler (heating the air flow 84 to reduce the temperature of refrigerant as it flows through the first heat exchanger 70). Refrigerant proceeds downstream along the refrigerant flowpath 64 to the expansion device 74 where it is expanded and its temperature further reduced. The cold refrigerant enters the second heat exchanger 72 (which acts as an evaporator, absorbing heat from the airflow 86 and heating the refrigerant as it flows through the second heat exchanger 72). Refrigerant discharged from the second heat exchanger 72 returns to the compressor inlet 66. Other details, including accumulators, valves, and sensors may be present but are not shown for ease of illustration.

[0021] FIG. 2 shows further details of an air flowpath 100 and exemplary positioning of components of the refrigeration system 60. In the exemplary case 20, the compressor 62 and first heat exchanger 70 are positioned within a compartment 102 of the base 38. The second heat exchanger 72 is positioned within a rear duct 104 between the rear wall 42 and the compartment 24. The rear duct 104 extends from a base duct 106 at a lower end of the compartment which has an inlet 108 at a lower end of the front opening. The rear duct 104 feeds a top duct 110 which has an outlet 112. The flow 86 produces a discharge flow 114 from the outlet which may

initiate/form an air curtain along the opening 46. Additional branching flows (not shown) may branch off the flow 86 and pass into the compartment 24. At least a portion of the flow 114 and any branching flows returns to the inlet 108 as an inlet flow 116. In the exemplary embodiment, the fan 82 is positioned proximate a junction of the rear duct 104 and base duct 106.

[0022] In a cooling mode, moisture in the inlet flow 116 may freeze on the heat exchanger 72 and may produce a frost accumulation which may lead to a blockage. Accordingly, a defrost mode may be initiated. Exemplary defrost may be via a heating element 117 (e.g., an electric resistance element 128) and/or via directing hot refrigerant to the heat exchanger 72 (instead of cold refrigerant). The defrost operation melts the frost which may flow downward as a flow 130 (e.g., of droplets) and reach a drain 132. An exemplary drain is formed proximate a lower end of the rear duct 104. The drain may include a trap 134 (e.g., a conventional J or S trap or a more complex trap such as that shown in JP2004353909). The drain, in turn, discharges water as one or more flows 140 into an evaporation vessel 142.

[0023] The exemplary vessel 142 has a plurality of compartments. The top/plan view of FIG. 4 shows an exemplary vessel 142 as having a first compartment 200 positioned to receive the water 140 from the drain (e.g., positioned immediately below the drain outlet). There are an exemplary two additional compartments 202 and 204 which, in the exemplary embodiment, are adjacent to the compartment 200 on opposite sides thereof. Compartments 202 and 204 are separated from compartment 200 by a wall 210 which may be lower than a perimeter wall 212 of the vessel 142. This permits overflow 220 from the compartment 200 to pass into the

compartments 202 and 204.

[0024] The exemplary vessel 142 is supported by springs 230 to allow the vessel to move between a relatively raised (high) position (e.g., FIG. 5) and a relatively lowered (low) position (e.g., FIG. 7). One or more of these positions may be determined by stops (e.g., 232 at the lowered position). The exemplary springs 230 are tension springs (e.g., metal tension coil springs) suspending the vessel from the upper wall of the base compartment 102. Exemplary layout of such springs is one spring at each of four corners of a rectangular planform vessel 142. In an exemplary embodiment, the at least one spring is sized such that a height at which the vessel is empty is at least 40mm above a height at which the vessel is full of water, more narrowly 50-100mm or 60-90mm (e.g., about 70mm). This may define a vertical range of motion which may be dictated by the stops.

[0025] The vessel 142 may be in its relatively raised position when there is no water accumulation. As water accumulates, the weight of the water will tend to drive the vessel 142 downward toward the lowered position (e.g., immediately or, with stops, after a certain threshold level of water has been collected). The received water initially fills the first chamber 200.

Eventually, the chamber 200 fills, initiating the overflow 220 to the chambers 202 and 204, thereby beginning to fill those chambers. Eventually, those chambers may fill. If stops are present for the lowered position, the vessel may reach the lowered position before complete filling.

[0026] To encourage evaporation of the water, a heating element 240 (FIG. 4) may be positioned to contact the water accumulation in the vessel 142. The exemplary heating element is at a fixed position so that, as water accumulates the vessel, the vessel lowers relative to the heating element maintaining the heat element relatively near the surface of the water

accumulation. The exemplary heating element may be formed as a portion of a refrigerant line along the refrigerant flowpath. For example, the springs may be sized and the heating element positioned so that at least half of the cross-section of the relevant portion of the heating element along the vessel 142 is immersed during at least half of the range of movement of the vessel 142.

[0027] One or more wicking elements 244 (e.g., sponges) may be positioned to be partially immersed in a water accumulation at least one of the compartments 200, 202, 204. An exemplary wicking element is filled relative to the body at a fixed height and has sufficient height so that its lower end is partially immersed in any accumulation in the vessel.

[0028] The exemplary heating element is formed as a portion of the discharge line 250 (FIG. 3) of the refrigerant flowpath 64. The discharge line extends between the compressor outlet 68 and the inlet to the first heat exchanger 70. During normal cooling mode operation, this will represent the warmest refrigerant in the system and is thus best able to facilitate evaporation of the water in the vessel 142. The particular implementation of FIG. 4 shows a cooling mode refrigerant flow 260 entering and exiting the heating element 240. In this cooling mode, a relatively downstream section 262 of the element and refrigerant flowpath is positioned within/along the first chamber 200. Relatively upstream sections 264 and 266 are in/along the chambers 204 and 202. The exemplary heating element configuration places the section 266 upstream of the section 264 in the cooling mode.

[0029] The effect of such a configuration is that water in the chamber 200 (which was received in the defrost mode) is preheated and overflows to the adjacent chambers 202 and 204. In the chambers 202 and 204 because the heating element is yet hotter than in the chamber 200 and because there is less depth of water, evaporation principally occurs from those chambers 202 and 204 rather than from the first chamber 200.

[0030] Although an embodiment is described above in detail, such description is not intended for limiting the scope of the present disclosure. It will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, when implemented in the reengineering of an existing system configuration, details of the existing configuration may influence or dictate details of any particular implementation. Accordingly, other embodiments are within the scope of the following claims.

Claims

CLAIMS What is claimed is:

1. A refrigerated case (20) comprising:

a body (22) having:

a refrigerated compartment (24);

an air fiowpath (100) extending from an inlet (108) positioned to receive air from the compartment to an outlet (112) positioned to discharge air to the compartment; and a drain (132);

a vessel (142) positioned to receive water (140) discharged from the drain;

a refrigerant fiowpath (64); and

a refrigerant-air heat exchanger (72) along the refrigerant fiowpath and within the air fiowpath,

wherein:

the vessel is supported to move between a lowered position and a raised position; and at least one spring (230) is coupled to the vessel to bias the vessel from the lowered position toward the raised position.

2. The refrigerated case of claim 1 wherein the vessel (142) has a plurality of compartments including:

a first compartment (200) positioned to receive said water from the drain; and

at least one additional compartment (202, 204) positioned to receive overflow (220) from the first compartment.

3. The refrigerated case of claim 2 further comprising:

at least one wicking element (244) positioned to be partially immersed in a water accumulation in at least one of the first compartment and the additional compartments.

4. The refrigerated case of claim 1 wherein:

the at least one spring comprises a plurality of tension coil springs suspending the vessel.

5. The refrigerated case of claim 1 wherein:

at least one spring is sized so that a height at which the vessel is empty is at least 40mm above a height at which the vessel is full of water.

6. The case of claim 1 further comprising:

a refrigeration system comprising:

said refrigerant flowpath (64);

a compressor (62) along the refrigerant flowpath downstream of the refrigerant-air heat exchanger (72) in a cooling mode of operation;

a first refrigerant-air-heat exchanger (70) being a heat rejection heat exchanger in the cooling mode and downstream of the compressor;

said refrigerant-air heat exchanger (72) as a second heat exchanger and being a heat absorption heat exchanger in the cooling mode; and

an expansion device (74) along the refrigerant flowpath, downstream of the first refrigerant-air heat exchanger and upstream of the second refrigerant-air heat exchanger in the cooling mode.

7. The case of claim 1 wherein:

the vessel has a plurality of compartments including:

a first compartment (200) that is positioned to receive said water from the drain; and

at least one additional compartment (202, 204) positioned to receive overflow from the first compartment; and

a refrigerant line, along the refrigerant flowpath, has respective sections in the first compartment and the at least one additional compartment.

8. A method for using the case of claim 1, the method comprising:

operating in a cooling mode wherein refrigerant is delivered to the refrigerant-air heat exchanger along the refrigerant flowpath to cool air along the air flowpath, causing condensate from the air flowpath to freeze onto the refrigerant-air heat exchanger as ice; and operating in a defrost mode wherein the ice is melted, causing the melted ice to flow to the drain and be discharged from the drain as said water,

wherein:

receipt of the water by the vessel increases an accumulation within the vessel and causes the vessel to descend.

9. The method of claim 8 further comprising:

heating the accumulation via refrigerant in at least one refrigerant line section (262, 264, 266) in the vessel.

10. The method of claim 9 wherein:

the at least one refrigerant line section remains stationary while the vessel descends and subsequently ascends.

11. A refrigerated case (20) comprising:

a body (22) having:

a refrigerated compartment (24);

an air flowpath (100) extending from an inlet (108) positioned to receive air from the compartment to an outlet (112) positioned to discharge air to the compartment; and a drain (132);

a vessel (142) positioned to receive water (140) discharged from the drain;

a refrigerant flowpath (64); and

a refrigerant-air heat exchanger (72) along the refrigerant flowpath and within the air flowpath,

wherein:

the vessel (142) has a plurality of compartments including:

a first compartment (200) positioned to receive said water from the drain; and at least one additional compartment (202, 204) positioned to receive overflow

(220) from the first compartment; and

a refrigerant line passes through the first compartment and the at least one additional compartment.

12. The case of claim 11 wherein:

the refrigerant line in the at least one additional compartment is upstream of the refrigerant line in the first compartment in a cooling mode of operation wherein the

refrigerant-air heat exchanger is operated as a heat absorption heat exchanger.

13. A method for using the case of claim 11, the method comprising:

operating in a cooling mode wherein refrigerant is delivered to the refrigerant-air heat exchanger along the refrigerant flowpath to cool air along the air flowpath, causing condensate from the air flowpath to freeze onto the refrigerant-air heat exchanger as ice; and

operating in a defrost mode wherein the ice is melted, causing the melted ice to flow to the drain and be discharged from the drain as said water,

wherein:

14. A method for using the case of claim 11, the method comprising:

wherein:

in the cooling mode, refrigerant along the refrigerant flowpath heats the water in the at least one additional compartment prior to heating the water in the first compartment.