US20170003062A1

US20170003062A1 - Multi-evaporator sequencing apparatus and method

Info

Publication number: US20170003062A1
Application number: US15/197,176
Authority: US
Inventors: William E. Olson, Jr.; Richard T. Miller
Original assignee: Manitowoc Foodservice Companies LLC
Current assignee: Emerson Automation Solutions GmbH
Priority date: 2015-07-02
Filing date: 2016-06-29
Publication date: 2017-01-05
Also published as: WO2017004212A1

Abstract

A refrigerant system includes a condenser and a plurality of evaporators each connected to the condenser. Each of the plurality of evaporators receives fluid from the condenser in a harvest mode, and at least two of the plurality of evaporators are in a harvest mode at different times.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 62/187,905, filed Jul. 2, 2015. The contents of U.S. Provisional Application No. 62/187,905, filed Jul. 2, 2015, are hereby incorporated by reference herein in their entirety.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure
The present disclosure relates generally to an apparatus and method for cooling with multiple evaporators. More particularly, the present disclosure relates to an apparatus and method for sequencing a harvest mode and a freezing mode of each of a plurality of evaporators.
2. Description of Related Art
Conventional commercial batch-style ice making machines bring in a certain amount of potable water, freeze a portion of that water into ice, harvest that ice, then repeat the process. These machines have one or more evaporators for the freezing and harvesting of ice. For example, referring to FIG. 1, ice making assembly 30 has an ice making machine 33 that makes ice and an ice bin 31 that stores ice.
FIGS. 2 and 3 illustrate schematically a water/ice system of ice making assembly 30, but does not show the ice bin 31 or reservoir. A water supply 1 provides source water. Attached lines control and direct the flow of water from the water supply to flow into a water sump 3. The sump is equipped with a level controller 2, a solenoid dump valve 9, a drain line 10, and is connected and supplies a water supply to the suction side of the circulating pump 4. Pump 4 circulates water from sump 3 to the distributor 7, where the water is directed over an evaporator plate 6. Evaporator plate has walls 6 a, 6 b, 6 c, 6 d that form ice having a shape, e.g., cubes.
The water from the distributor 7 is directed across the evaporator plate 6 and, if not frozen to form ice on a first pass, is collected by the water curtain 5. This collected water is allowed to flow down the water curtain into the water sump or water reservoir 3, where it is collected and again circulated by the circulating pump 4 to the distributor 7 and recycled across evaporator plate 6 during the freezing cycle. Once the ice forming on the evaporator plate 6 has reached a certain thickness, the water flowing over the surface of that frozen ice product reaches contact with the ice thickness probe 8, which signals the controller to stop the freeze mode and begin the harvest mode.
FIG. 4 shows an example of ice making assembly 30 that has two evaporator plates 6. Each of evaporator plates 6 is connected to a refrigerant system having multiple evaporators, one for each evaporator plate 6, which operates in the freeze mode and the harvest mode.
Referring to FIG. 5, an example of a refrigerant system 100 that has multiple evaporators 102 is shown. Refrigerant system 100 has four evaporators 104, 106, 108, 110. Evaporators 102 are each in thermal contact with an evaporator plate to heat and cool the evaporator plate. For example, one of evaporator plates 6 may be heated and cooled by evaporator 104 and the other of evaporator plates 6 may be cooled by evaporator 106 shown in FIGS. 2-4. Refrigerant system 100 comprises a condenser 111, evaporators 104, 106, 108, 110, a compressor 114, refrigerant supply line 120, a drier 121, a receiver 122, harvest solenoid valves 123, and expansion valves 113 for each of evaporators 102.
Referring to FIG. 6, in the freeze mode, each of evaporators 104, 106, 108, 110 inlet has low-pressure liquid 132 that expands, absorbs heat, and evaporates, changing to a low-pressure vapor 134 in evaporator serpentine 112. Compressor 114 pumps low-pressure vapor 134 from inlets of each of evaporators 104, 106, 108, 110 to condenser 111 increasing the pressure forming high pressure vapor 136 at condenser 111. In condenser 111, heat is removed from high pressure vapor 136, which then condenses and becomes a high-pressure liquid 138. This high-pressure liquid 138 drains from condenser 111 into receiver tank 122 to provide a buffer for refrigerant as demand varies. One of expansion devices 113 is between condenser 111 and each of evaporators 104, 106, 108, 110. Immediately preceding each of expansion devices 113 is drier 121, which prevents plugging of the valve or tube by retaining scale, dirt, and moisture. As high-pressure liquid 138 enters the evaporators 104, 106, 108, 110, it is subjected to a much lower pressure due to the suction of compressor 114 and a pressure drop across expansion devices 113. Thus, the refrigerant tends to expand and evaporate. In order to evaporate, the liquid must absorb heat from the air passing over evaporators 104, 106, 108, 110 forming low pressure liquid 132. Harvest solenoid valves 123 are closed during the freeze mode.
Referring to FIG. 7, when the ice making system goes into its harvest mode, each of open expansion devices 113 are closed and each of closed harvest solenoid valves 123 are opened allowing high pressure vapor 136 in compressor 114 to flow through refrigerant supply line 120 into each of evaporators 104, 106, 108, 110. High pressure vapor 136 flows toward each of evaporators 104, 106, 108, 110 through each of harvest solenoid valves 123 lowering the pressure to form low-pressure vapor 134. Low-pressure vapor 134 flows through each of evaporators 104, 106, 108, 110 lowering pressure further forming low pressure liquid 132. Low pressure liquid 132 flows from each of evaporators 104, 106, 108, 110 to compressor 114.
Each of evaporators 102 are cooled by boiling refrigerant in evaporator serpentine 112 while water is circulated over evaporator plates 6 to freeze ice when the machine is in “freeze mode”. Evaporators 102 are warmed by routing high pressure vapor 136 that is at a higher temperature than ice that is formed on evaporator plates 6 through the evaporator serpentine 112 to melt ice and allow gravity to pull an ice slab off evaporator plates 6 when the machine is in “harvest mode”. The use of multiple evaporators 102 in these conventional machines is strictly to add more evaporator surface area than could be fit in the given machine size with only one large evaporator. All the evaporators 102 in the system are synchronized in their freezing modes and harvesting modes so that evaporators 104, 106, 108, 110 all operate in the same mode, freezing mode or harvesting mode, all at the same time.
The synchronized nature of all evaporators 102 in a conventional multi-evaporator machine used in refrigerant system 100 results in a maximum heat load condition from all evaporators 102 happening at the same time, as well as a minimum heat load condition from all evaporators 102 happening at the same time. This leads to large variations in operating conditions for compressor 114, from very high discharge pressure early in the “freeze mode” to very low suction pressure late in the “freeze mode.” These times of high discharge pressure or low suction pressure result in the compressor running at less efficient points than the average load condition due to reduced refrigerant throughput.
Accordingly, it has been determined by the present disclosure, there is a need for spreading out the refrigeration load of a refrigeration system throughout the freeze mode (load leveling) to best utilize cooling capacity of the refrigerant system and to maximize its efficiency.

SUMMARY

A refrigerant system is provided that includes a condenser and a plurality of evaporators each connected to the condenser. Each of the plurality of evaporators receives fluid from the condenser in a harvest mode, and at least two of the plurality of evaporators are in a harvest mode at different times.
The above-described and other advantages and features of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A provides an illustration of a conventional automatic ice making machine.

FIGS. 2 and 3 provide line diagrams and drawings for an embodiment of a water/ice system of the conventional ice machine of FIG. 1.

FIG. 4 is a perspective view of an ice making machine with components removed which can be adapted to have evaporator plates of the conventional ice machine of FIG. 1.

FIG. 5 provides a line diagram describing an embodiment for the coolant/refrigerant system of the conventional ice machine of FIG. 1 having four evaporators.

FIG. 6 provides a line diagram describing the embodiment for the coolant/refrigerant system of the conventional ice machine of FIG. 5 in a freeze mode.

FIG. 7 provides a line diagram describing the embodiment for the coolant/refrigerant system of the conventional ice machine of FIG. 5 in a harvest mode.

FIG. 8 provides a line diagram describing a refrigerant system of the present disclosure having four evaporators with a first evaporator, a second evaporator, and a third evaporator in freeze mode and a fourth evaporator in harvest mode.

FIG. 9 provides a line diagram describing the refrigerant system of FIG. 8 having the first evaporator in harvest mode and the second evaporator, the third evaporator and the fourth evaporator in freeze mode.

FIG. 10 provides a line diagram describing the refrigerant system of FIG. 8 having the second evaporator in harvest mode and the first evaporator, the third evaporator and the fourth evaporator in freeze mode.

FIG. 11 provides a line diagram describing the refrigerant system of FIG. 8 having the third evaporator in harvest mode and the first evaporator, the second evaporator and the fourth evaporator in freeze mode.

FIG. 12 provides a line diagram describing the refrigerant system of FIG. 8 having the fourth evaporator in harvest mode and the first evaporator, the second evaporator and the third evaporator in freeze mode.

FIG. 13 provides a process flowchart diagram describing a method for controlling the refrigerant system of FIG. 8.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring to the drawings and in particular to FIG. 8, an exemplary embodiment of a refrigerant system of the present disclosure is generally referred to by 200. Refrigerant system 200 has a compressor 201 connected to condenser 202. Condenser 202 is connected to a plurality of evaporators 205. FIG. 8 has four evaporators: first evaporator 205 a, second evaporator 205 b, third evaporator 205 c and fourth evaporator 205 d. Additional or fewer evaporators 205 may be included in refrigerant system 200, however, at least two evaporators 205 are used. Between the connection of condenser 202 and each of evaporators 205 is a liquid line valve 204. Each of evaporators 205 is connected to compressor 201. Between the connection of compressor 201 and each of evaporators 205 is a suction line valve 209. Between each of evaporators 205 are a check valve 206, which is allows flow of fluid only in a single direction, and an expansion valve 208. An expansion valve header 207 is a conduit that connects each of check valves 206 and expansion valves 208 to one another. A liquid line header 203 is a conduit that connects each of liquid line valves 204 to one another. A suction line header 210 is a conduit that connects each of suction line valves 209 to one another. One or more conduits may connect compressor 201 condenser 202, liquid line header 203, liquid line valves 204, evaporators 205, check valves 206, expansion valve header 207, expansion valves 208, suction line valves 209 and suction line header 210 to one another to circulate refrigerant therein. Refrigerant may include R404A, R410A, R32, or the like. Refrigerant system 200 has liquid line valves 204 of first evaporator 205 a, a second evaporator 205 b, and a third evaporator 205 c in a closed position and suction line valves 209 of first evaporator 205 a, a second evaporator 205 b, and a third evaporator 205 c in an open position so that first evaporator 205 a, a second evaporator 205 b, and a third evaporator 205 c are in a freeze mode. Refrigerant system 200 has liquid line valve 204 of fourth evaporator 205 d in an open position and suction line valve 209 of fourth evaporator 205 d in a closed position so that fourth evaporator 205 d is in a harvest mode.
Referring to FIG. 9, suction line valve 209 of first evaporator 205 a is in a closed position blocking refrigerant from flowing from first evaporator 205 a to compressor 201. Liquid line valve 204 of first evaporator 205 a is in an open position allowing refrigerant to flow from condenser 202 to first evaporator 205 a. Suction line valves 209 of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d are in an opened position allowing refrigerant to flow to compressor 201 from each of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d. Liquid line valves 204 of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d are in a closed position blocking refrigerant from flowing from condenser 202 to each of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d.
In operation, low pressure refrigerant vapor 234 is compressed in compressor 201 to form high pressure refrigerant vapor 236. High pressure refrigerant vapor 236 flows from compressor 201 through condenser 202 to reject heat, condensing high pressure refrigerant vapor 236 to form high pressure liquid 238. High pressure liquid 238 is routed from condenser 202 through liquid line header 203. High pressure liquid 238 travels through open liquid line valve 204 for first evaporator 205 a that is in a harvest mode. High pressure liquid 238 travels through first evaporator 205 a that is in harvest mode. High pressure liquid 238 travels through check valve 206 for first evaporator 205 a in the harvest mode. High pressure liquid 238 is routed through expansion valve header 207, splitting into separate streams for each of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d that are each in a freeze mode. High pressure liquid 238 travels through expansion valves 208 for each of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d forming low pressure liquid 232 in the freeze mode. Low pressure liquid 232 travels through second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d that are in freeze mode, evaporating refrigerant from low pressure liquid 232 forming low pressure vapor 234. Low pressure vapor 234 streams travel through suction line valves 209. Low pressure vapor 234 streams combine in suction line header 210. Low pressure vapor 234 returns to compressor 201. This cycle of refrigerant transforming from low pressure vapor 234 to high pressure refrigerant vapor 236 to high pressure liquid 238 to low pressure liquid 232 and back to low pressure vapor 234 in refrigerant system 200 repeats until the harvest mode of first evaporator 205 a and the freeze mode of second evaporator 205 b, third evaporator 205 c, and/or fourth evaporator 205 d are completed. Freeze and harvest times may be determined by monitoring water level in the water sump, for example, sump 3, monitoring suction pressure or temperature, or based on a time value or array of time values of the harvest cycle versus ambient temperatures.
Each of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d are cooled by low pressure liquid 232 while water is circulated over evaporator plates, e.g., evaporator plates 6 of FIG. 4, that are in thermal contact with one of second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d to freeze ice in the freeze mode. First evaporator 205 a is warmed by routing high pressure liquid 238 that is at a higher temperature than ice that is formed on an evaporator plate, e.g., one of evaporator plates 6 of FIG. 4, to melt ice and allow gravity to pull an ice slab off evaporator plate 6 when in the harvest mode.
First evaporator 205 a has a liquid line heat harvest for the harvest mode that is accomplished by routing refrigerant from an outlet of condenser 202 through first evaporator 205 a while the remaining second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d are in the freeze mode. After high pressure liquid 238 exits first evaporator 205 a that is in harvest mode, a flow of high pressure liquid 238 is split and routed to expansion devices 208 for each of the remaining second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d that are in the freeze mode.
Refrigerant system 200 has a controller 214. Controller 214 has a processor 216 and a memory 218. Memory 218 stores a program for operation of refrigerant system 200 that is executed by processor 216. After a certain amount of time, refrigerant system 200 proceeds to harvest second evaporator 205 b and returns first evaporator 205 previously in the harvest mode into a freeze mode. Controller 214 is connected to liquid line valves 204 and suction line valves 209. Memory 218 stores the program for operation of refrigerant system 200 that is executed by processor 216 so that controller 214 can open and close each of liquid line valves 204 and suction line valves 209.
Referring to FIG. 10, suction line valve 209 of first evaporator 205 a is moved to an open position allowing refrigerant to flow from first evaporator 205 a to compressor 201. Liquid line valve 204 of first evaporator 205 a is moved to a closed position blocking refrigerant to flow from condenser 202 to first evaporator 205 a. Suction line valves 209 of third evaporator 205 c and fourth evaporator 205 d are maintained in the opened position allowing refrigerant to flow to compressor 201 from each of third evaporator 205 c and fourth evaporator 205 d. Liquid line valves 204 of third evaporator 205 c and fourth evaporator 205 d are maintained in a closed position blocking refrigerant from flowing from condenser 202 to each of third evaporator 205 c and fourth evaporator 205 d. Suction line valve 209 of second evaporator 205 b is moved to a closed position blocking refrigerant from flowing from second evaporator 205 b to compressor 201. Liquid line valve 204 of second evaporator 205 b is moved to an open position allowing refrigerant to flow from condenser 202 to second evaporator 205 b.
In operation, low pressure refrigerant vapor 234 is compressed in compressor 201 to form high pressure refrigerant vapor 236. High pressure refrigerant vapor 236 flows from compressor 201 through condenser 202 to reject heat, condensing high pressure refrigerant vapor 236 to form high pressure liquid 238. High pressure liquid 238 is routed from condenser 202 through liquid line header 203. High pressure liquid 238 travels through open liquid line valve 204 for second evaporator 205 b that is in a harvest mode. High pressure liquid 238 travels through second evaporator 205 b that is in harvest mode. High pressure liquid 238 travels through check valve 206 for second evaporator 205 b in the harvest mode. High pressure liquid 238 is routed through expansion valve header 207, splitting into separate streams for each of first evaporator 205 a, third evaporator 205 c, and fourth evaporator 205 d that are each in a freeze mode. High pressure liquid 238 travels through expansion valves 208 for each of first evaporator 205 a, third evaporator 205 c, and fourth evaporator 205 d forming low pressure liquid 232 in the freeze mode. Low pressure liquid 232 travels through first evaporator 205 a, third evaporator 205 c, and fourth evaporator 205 d that are in freeze mode, evaporating refrigerant from low pressure liquid 232 forming low pressure vapor 234. Low pressure vapor 234 streams travel through suction line valves 209 of first evaporator 205 a, third evaporator 205 c, and fourth evaporator 205 d. Low pressure vapor 234 streams combine in suction line header 210. Low pressure vapor 234 returns to compressor 201. This cycle of refrigerant transforming from low pressure vapor 234 to high pressure refrigerant vapor 236 to high pressure liquid 238 to low pressure liquid 232 and back to low pressure vapor 234 in refrigerant system 200 repeats until the harvest mode of second evaporator 205 b and the freeze mode of first evaporator 205 a, third evaporator 205 c, and/or fourth evaporator 205 d are completed.
Referring to FIG. 11, when the harvest mode of second evaporator 205 b and the freeze mode of third evaporator 205 c are completed, suction line valve 209 of second evaporator 205 b is moved to the open position allowing refrigerant to flow from second evaporator 205 b to compressor 201. Liquid line valve 204 of second evaporator 205 b is moved to the closed position blocking refrigerant to flow from condenser 202 to second evaporator 205 b. Suction line valves 209 of first evaporator 205 a and fourth evaporator 205 d are maintained in the opened position allowing refrigerant to flow to compressor 201 from each of first evaporator 205 a and fourth evaporator 205 d. Liquid line valves 204 of first evaporator 205 a and fourth evaporator 205 d are maintained in a closed position blocking refrigerant from flowing from condenser 202 to each of first evaporator 205 a and fourth evaporator 205 d. Suction line valve 209 of third evaporator 205 c is moved to a closed position blocking refrigerant from flowing from third evaporator 205 c to compressor 201. Liquid line valve 204 of third evaporator 205 c is moved to an open position allowing refrigerant to flow from condenser 202 to third evaporator 205 c.
In operation, low pressure refrigerant vapor 234 is compressed in compressor 201 to form high pressure refrigerant vapor 236. High pressure refrigerant vapor 236 flows from compressor 201 through condenser 202 to reject heat, condensing high pressure refrigerant vapor 236 to form high pressure liquid 238. High pressure liquid 238 is routed from condenser 202 through liquid line header 203. High pressure liquid 238 travels through open liquid line valve 204 for third evaporator 205 c that is in a harvest mode. High pressure liquid 238 travels through third evaporator 205 c that is in harvest mode. High pressure liquid 238 travels through check valve 206 for third evaporator 205 c in the harvest mode. High pressure liquid 238 is routed through expansion valve header 207, splitting into separate streams for each of first evaporator 205 a, second evaporator 205 b, and fourth evaporator 205 d that are each in a freeze mode. High pressure liquid 238 travels through expansion valves 208 for each of first evaporator 205 a, second evaporator 205 b, and fourth evaporator 205 d forming low pressure liquid 232 in the freeze mode. Low pressure liquid 232 travels through first evaporator 205 a, second evaporator 205 b, and fourth evaporator 205 d that are in freeze mode, evaporating refrigerant from low pressure liquid 232 forming low pressure vapor 234. Low pressure vapor 234 streams travel through suction line valves 209 of first evaporator 205 a, second evaporator 205 b, and fourth evaporator 205 d. Low pressure vapor 234 streams combine in suction line header 210. Low pressure vapor 234 returns to compressor 201. This cycle of refrigerant transforming from low pressure vapor 234 to high pressure refrigerant vapor 236 to high pressure liquid 238 to low pressure liquid 232 and back to low pressure vapor 234 in refrigerant system 200 repeats until the harvest mode of third evaporator 205 c and the freeze mode of first evaporator 205 a, second evaporator 205 b, and/or fourth evaporator 205 d are completed.
Referring to FIG. 12, when the harvest mode of third evaporator 205 c and the freeze mode of fourth evaporator 205 d are completed, suction line valve 209 of third evaporator 205 c is moved to the open position allowing refrigerant to flow from third evaporator 205 c to compressor 201. Liquid line valve 204 of third evaporator 205 c is moved to the closed position blocking refrigerant to flow from condenser 202 to third evaporator 205 c. Suction line valves 209 of first evaporator 205 a and second evaporator 205 b are maintained in the opened position allowing refrigerant to flow to compressor 201 from each of first evaporator 205 a and second evaporator 205 b. Liquid line valves 204 first evaporator 205 a and second evaporator 205 b are maintained in a closed position blocking refrigerant from flowing from condenser 202 to each of first evaporator 205 a and second evaporator 205 b. Suction line valve 209 of fourth evaporator 205 d is moved to a closed position blocking refrigerant from flowing from fourth evaporator 205 d to compressor 201. Liquid line valve 204 of fourth evaporator 205 d is moved to an open position allowing refrigerant to flow from condenser 202 to fourth evaporator 205 d.
In operation, low pressure refrigerant vapor 234 is compressed in compressor 201 to form high pressure refrigerant vapor 236. High pressure refrigerant vapor 236 flows from compressor 201 through condenser 202 to reject heat, condensing high pressure refrigerant vapor 236 to form high pressure liquid 238. High pressure liquid 238 is routed from condenser 202 through liquid line header 203. High pressure liquid 238 travels through open liquid line valve 204 for fourth evaporator 205 d that is in a harvest mode. High pressure liquid 238 travels through fourth evaporator 205 d that is in harvest mode. High pressure liquid 238 travels through check valve 206 for fourth evaporator 205 d in the harvest mode. High pressure liquid 238 is routed through expansion valve header 207, splitting into separate streams for each of first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c that are each in a freeze mode. High pressure liquid 238 travels through expansion valves 208 for each of first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c forming low pressure liquid 232 in the freeze mode. Low pressure liquid 232 travels through first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c that are in freeze mode, evaporating refrigerant from low pressure liquid 232 forming low pressure vapor 234. Low pressure vapor 234 streams travel through suction line valves 209 of first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c, Low pressure vapor 234 streams combine in suction line header 210. Low pressure vapor 234 returns to compressor 201. This cycle of refrigerant transforming from low pressure vapor 234 to high pressure refrigerant vapor 236 to high pressure liquid 238 to low pressure liquid 232 and back to low pressure vapor 234 in refrigerant system 200 repeats until the harvest mode of fourth evaporator 205 d and the freeze mode of first evaporator 205 a, second evaporator 205 b, and/or third evaporator 205 c are completed.
Refrigerant system 200 has a liquid line heat harvest that is accomplished by routing refrigerant from an outlet of condenser 202 through at least one of first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and/or fourth evaporator 205 d while the remaining evaporators of first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and/or fourth evaporator 205 d are in freeze mode. After high pressure liquid 238 exits the evaporator currently in harvest mode, a flow of high pressure liquid 238 is split and routed to expansion devices 208 for the remaining first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and/or fourth evaporator 205 d that are in freeze mode. After a certain amount of time, refrigerant system 200 proceeds to harvest another of first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and/or fourth evaporator 205 d and returns the evaporator previously in harvest mode back into freeze mode.
Refrigerant system 200 has at least one of first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d in harvest mode while the remaining evaporators 205 of first evaporator 205 a, second evaporator 205 b, third evaporator 205 c, and fourth evaporator 205 d are in freeze mode at all times. More than one evaporator 205 may be in harvest mode at a time.
Referring to FIG. 13, a method 300 that can be used with refrigeration system 200 is shown. Method 300 begins at step 302 and proceeds to step 304. Step 304 determines if the refrigerant system in an ice making mode. If the refrigerant system 200 is not in an ice making mode, then method 300 repeats step 302. If the refrigerant system 200 is in an ice making mode where ice is made, for example, in an ice making machine 30 shown in FIG. 4, then evaporators are identified by numbers where n equals the number of evaporators in the refrigerant system, for example, first evaporator 205 a, second evaporator 205 b, third evaporator, 205 c and fourth evaporator 205 d so that n equal four. Method 300 proceeds from step 306 to step 308 where liquid line valve 204 of evaporator n, for example, fourth evaporator 205 d, and suction line valves of the remaining evaporators, for example, first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c, are maintained or opened to an open position, and suction line valve of evaporator n, for example, fourth evaporator 205 d, and liquid line valves of the remaining evaporators, for example, first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c, are closed or maintained in a closed position so that evaporator n, for example, fourth evaporator 205 d, is in a harvest mode and the remaining evaporators, for example, first evaporator 205 a, second evaporator 205 b, and third evaporator 205 c, are in freeze mode.
Method 300 proceeds from step 308 to step 310 where it is determined if the harvest mode of evaporator n, for example, fourth evaporator 205 d, and the freeze mode of one of the remaining evaporators, for example, third evaporator 205 c, has ended. If the harvest cycle and freeze cycle have not ended, then step 310 is repeated. If the harvest cycle and freeze cycle have ended, then method 200 proceeds to step 312. In step 312 it is determined if refrigerant system 200 is in the ice making mode. If refrigerant system 200 is not in the ice making mode, then method 300 ends in step 320. If refrigerant system 200 is in the ice making mode, then method 300 proceeds to step 314 where the value of n is changed to n minus one, for example, n was four and will be changed to three. Method 300 then proceeds to step 316 where it is determined if n equals zero. If n does not equal zero, for example, n equals three, then method 200 proceeds to step 308, and method 200 repeats steps 308-316, for example, with third evaporator 205 c in harvest mode and first evaporator 205 a, second evaporator 205 b, and fourth evaporator 205 d in freeze mode. If n equals zero, then method 200 proceeds from step 316 to step 318. If refrigerant system 200 is not in the ice making mode, then method 300 ends in step 320. If refrigerant system 200 is in the ice making mode, then method proceeds to step 306, and steps 306-316 are repeated.
Controller 214 may be coupled to a network, e.g., the Internet. Controller 214 may include a user interface, processor 216, and memory 218. Although controller 214 is represented herein as a standalone device, it is not limited to such, but instead can be coupled to other devices (not shown) via the network. Processor 216 can be configured of logic circuitry that responds to and executes instructions.
Memory 218 stores data and instructions for controlling the operation of processor 216. Memory 218 may be implemented in a random access memory (RAM), a hard drive, a read only memory (ROM), or a combination thereof. One component of memory 218 is a program module 220.
Program module 220 contains instructions for controlling processor 216 to execute the methods described herein. For example, as a result of execution of program module 220, processor 216 executes method 300. The term “module” is used herein to denote a functional operation that may be embodied either as a stand-alone component or as an integrated configuration of a plurality of sub-ordinate components. Thus, program module 220 may be implemented as a single module or as a plurality of modules that operate in cooperation with one another. Moreover, although program module 220 is described herein as being installed in memory 218, and therefore being implemented in software, it could be implemented in any of hardware (e.g., electronic circuitry), firmware, software, or a combination thereof.
The user interface includes an input device, such as a keyboard or speech recognition subsystem, for enabling a user to communicate information and command selections to processor 216. The user interface also includes an output device such as a display or a printer. A cursor control such as a mouse, track-ball, or joy stick, allows the user to manipulate a cursor on the display for communicating additional information and command selections to processor 216. The user interface may be provided so that the number of evaporators 205 included in refrigerant system 200 may be changed.
This present invention accomplishes the goal of refrigeration load leveling in a multi-evaporator systems by removing the evaporator synchronization that exists in conventional multiple evaporator batch-style ice making machines. Instead, refrigerant system 200 sequences evaporators 205 so their maximum and minimum refrigerant loads do not happen at the same time. To do this, the nature of the harvest mode has been changed from the conventional hot gas bypass harvest to a liquid line heat harvest. This change in harvest mechanism allows the system to have one or more evaporators 205 in harvest mode while the remaining evaporator(s) are in freeze mode. This would not be desirable in systems using hot gas bypass harvest as the evaporator(s) in harvest mode would disrupt the suction pressure of the evaporator(s) in freeze mode.
Refrigerant system 200 saves energy by sequencing the harvest and freeze modes of evaporators 205 so that evaporators 205 are not all in the harvest mode at once or all in the freeze mode at once. This avoids having a maximum heat load condition from all evaporators 205 happening at the same time, as well as a minimum heat load condition from all evaporators 205 happening at the same time to avoid large variations in operating conditions for compressor 201, from very high discharge pressure early in the freeze mode to very low suction pressure late in the freeze mode, which result in the compressor running at less efficient points than the average load condition. By avoiding large variations in operating conditions for compressor 201 energy is saved and larger or a greater number of evaporators 205 may be used relative to a size of compressor 201 over the prior art. Moreover, refrigerant systems 200 are limited in size by space needed for condenser 202 space which relates to a maximum load on a condenser so that avoid large variations in operating conditions also allows larger or a greater number of evaporators 205 may be used relative to a size of condenser 202 over the prior art. Furthermore, avoiding large variations in operating conditions will also lead to a greater yield of the amount of ice made using refrigerant system 200.
It should also be noted that the terms “first”, “second”, “third”, “upper”, “lower”, and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated.
While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated, but that the disclosure will include all embodiments falling within the scope of the appended claims.

Claims

What is claimed is:

1. A refrigerant system comprising:

a condenser;

a plurality of evaporators each connected to said condenser, each of said plurality of evaporators receiving refrigerant from said condenser in a harvest mode, at least two of said plurality of evaporators being in a harvest mode at different times.

2. The refrigerant system of claim 1, further comprising a compressor connected to each of said plurality of evaporators, wherein said compressor receives fluid from one or more of said plurality of evaporators in a freeze mode, and wherein said condenser is connected to said compressor.

3. The refrigerant system of claim 2, further comprising a plurality of liquid line valves, wherein each of said plurality of liquid line valves is connected between said condenser and one of said plurality of evaporators.

4. The refrigerant system of claim 3, further comprising a plurality of suction line valves, wherein each of said plurality of suction line valves is connected between said compressor and one of said plurality of evaporators.

5. The refrigerant system of claim 4, further comprising a plurality of check valves and a plurality of expansion valves, wherein each of said plurality of check valves is between one of said plurality of expansion valves and one of said plurality of evaporators.

6. The refrigerant system of claim 4, wherein each of said plurality of liquid line valves that is between said condenser and said one of said plurality of evaporators is in an open position allowing flow of said refrigerant from said condenser to said one of said plurality of evaporators when said one of said plurality of evaporators is in said harvest mode.

7. The refrigerant system of claim 6, wherein each of said plurality of suction line valves that is between said compressor and said one of said plurality of evaporators is in a closed position blocking flow of said refrigerant from said one of said plurality of evaporators to said compressor when said one of said plurality of evaporators is in said harvest mode.

8. The refrigerant system of claim 4, wherein each of said plurality of liquid line valves that is between said condenser and said one of said plurality of evaporators is in a closed position blocking flow of said refrigerant from said condenser to said one of said plurality of evaporators when said one of said plurality of evaporators is in said freeze mode.

9. The refrigerant system of claim 8, wherein each of said plurality of suction line valves that is between said compressor and one of said plurality of evaporators is in an open position allowing flow of said refrigerant from said one of said plurality of evaporators to said compressor when said one of said plurality of evaporators is in said freeze mode.

10. The refrigerant system of claim 9, further comprising a controller that moves said plurality of liquid line valves between said open position and said closed position, and wherein said controller moves said plurality of suction line valves between said open position and said closed position.

11. A method for a refrigerant system comprising:

providing a condenser and a plurality of evaporators each connected to said condenser, each of said plurality of evaporators receiving refrigerant from said condenser in a harvest mode, and at least two of said plurality of evaporators being in a harvest mode at different times; and

operating a first evaporator of said plurality of evaporators in said harvest mode with said refrigerant flowing through said first evaporator from said condenser while simultaneously operating a second evaporator of said plurality of evaporators in a freeze mode with said refrigerant from said first evaporator flowing through said second evaporator to said compressor.

12. The method of claim 11, further comprising moving a first suction line valve of said first evaporator to a closed position and moving a first liquid line valve of said first evaporator to an open position to commence said harvest mode.

13. The method of claim 11 further comprising moving a second suction line valve of said second evaporator to an open position and moving a second liquid line valve of said second evaporator to a closed position to commence said freeze mode.

14. The method of claim 12, further comprising moving said first suction line valve of said first evaporator to an open position and moving said first liquid line valve of said first evaporator to a closed position to end said harvest mode and commence a freeze mode of said first evaporator.

15. The method of claim 13, further comprising moving said second suction line valve of said second evaporator to a closed position and moving said second liquid line valve of said second evaporator to an open position to end said freeze mode and commence a harvest mode of said second evaporator.