Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D11/00—Self-contained movable devices, e.g. domestic refrigerators
  • F25D11/006—Self-contained movable devices, e.g. domestic refrigerators with cold storage accumulators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D25/00—Charging, supporting, and discharging the articles to be cooled
  • F25D25/02—Charging, supporting, and discharging the articles to be cooled by shelves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2700/00—Means for sensing or measuring; Sensors therefor
  • F25D2700/12—Sensors measuring the inside temperature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2700/00—Means for sensing or measuring; Sensors therefor
  • F25D2700/14—Sensors measuring the temperature outside the refrigerator or freezer
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D2700/00—Means for sensing or measuring; Sensors therefor
  • F25D2700/16—Sensors measuring the temperature of products
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
  • F25D29/00—Arrangement or mounting of control or safety devices
  • F25D29/008—Alarm devices

Definitions

• the present invention relates in general to refrigeration systems, which can used, for example, for the cold storage of perishables.
• a cold storage system includes an enclosed structure having an opening sealed by a door.
• a mechanical refrigeration unit maintains an interior of the enclosed structure within a selected temperature range.
• the cold storage system may further include within the enclosed structure a rack system having one or more shelves for supporting refrigerated goods.
• the rack system additionally support endothermic phase change material (PCM) providing a capacitive cooling effect within the enclosed structure.
• PCM phase change material
• the PCM is contained in a plurality of overhead PCM containers supported by one or more support members of the rack system.
• the plurality of overhead PCM containers includes endothermic PCM tubes that are disposed on one or more horizontal support members that securely attach to a plurality of vertical supports.
• the vertical supports may be reinforced by a horizontal cross beam bracket.
• the plurality of adjustable height vertical supports adjusts a height placement of the plurality of overhead PCM containers.
• additional PCM containers may be supported by the one or more shelves.
• these additional PCM containers can be modularly reconfigurable to accommodate various storage shelf configurations.
• the additional PCM container may be disposed in a plurality of under-shelf support brackets attached to the undersides of adjustable storage shelves of the cold storage rack.
• the cold storage system may includes a temperature monitor for controlling the mechanical refrigeration unit to maintain ambient temperature in the enclosed structure based upon at least a temperature of the endothermic PCM and an ambient temperature.
• the temperature monitor includes an outer temperature sensor for measuring a temperature of endothermic PCM adjacent to an inner surface of the PCM container, and an inner temperature sensor for measuring a temperature of endothermic PCM located at a farthest distance away from the inner surface of the PCM container.
• a cold storage rack includes one or more shelves for supporting refrigerated goods.
• the cold storage rack includes one or more support members supporting a plurality of overhead PCM containers containing endothermic PCM that provides a capacitive cooling effect with a mechanical refrigeration unit within a cold storage structure.
• the rack system may also include additional PCM containers supported by the one or more shelves.
• these additional PCM containers can be disposed in a plurality of under-shelf support brackets attached to the undersides of adjustable storage shelves of the cold storage rack and may be modularly reconfigurable to accommodate various storage shelf configurations.
• Figure 1 is a perspective view of an exemplary cold storage system in accordance with one embodiment
• Figure 2A is a partial perspective view of an exemplary cold storage rack in accordance with one embodiment
• Figures 2B-2C depict multiple configurations of PCM containers in accordance with one embodiment
• Figure 3 is a top plan view of several cold storage racks in a modular configuration
• Figure 4 is a side elevation view of an exemplary cold storage rack in accordance with one embodiment
• a cold storage system employs endothermic phase change material (PCM) within an enclosed, refrigerated chamber in a manner that leverages the features of conventional mechanical refrigeration units employing forced-air chilling.
• PCM phase change material
• a bimodal cold storage system as disclosed herein advantageously employs a "passive" heat exchange mode in the form of an endothermic PCM container compatibly deployed within a refrigerated structure.
• a "bimodal" cold storage system refers to a heat extraction/absorption system employing passive heat exchange mechanism in the form of an endothermic PCM in conjunction with an active heat exchange mechanism in the form of a forced-air mechanical refrigeration unit.
• the bimodal cold storage system efficiently addresses problems and costs associated with conventional refrigerated cold storage structures, including uneven cooling of temperature sensitive goods and ice buildup resulting from excessive condensation within the cold storage structure. Furthermore, the bimodal cold storage system's cooling mechanism reduces the required active operating time and excessive cycling of the mechanical refrigeration unit. Such reduction of active operating time and cycling of the mechanical refrigeration unit consequently reduces the overall power (kW) and energy (kWh) demands of the cold storage system, reduces repair and maintenance costs of the mechanical refrigeration unit, and extends the life the mechanical refrigeration unit.
• the cold storage system can be implemented within a refrigerated fixed structure (e.g., a cold storage cooler, cold storage freezer, cold storage room or cold storage warehouse) or portable cargo container or trailer having a conventional forced-air mechanical refrigeration unit that produces and directs chilled air into the interior of the refrigerated structure as required to lower and then maintain the temperature within the refrigerated structure at or below a predetermined temperature.
• a refrigerated fixed structure e.g., a cold storage cooler, cold storage freezer, cold storage room or cold storage warehouse
• portable cargo container or trailer having a conventional forced-air mechanical refrigeration unit that produces and directs chilled air into the interior of the refrigerated structure as required to lower and then maintain the temperature within the refrigerated structure at or below a predetermined temperature.
• the cold storage system advantageously employs a "passive" heat exchange mode enabled by a rack system.
• the rack system is installed and compatibly deployed inside the cold storage structure to support endothermic PCM in various installation configurations.
• the chilled airflow from the mechanical refrigeration unit is used to bring the endothermic PCM to the required phase change or stasis temperature.
• passive mode enabled when the endothermic storage material has reached its stasis temperature, the mechanical refrigeration unit deactivates, and the activated (i.e., capacitively charged) endothermic PCM serves as a suspended, non-mechanically driven heat sink for a passive thermal convection mechanism wherein a passive convective air current resulting from natural thermal circulation is circulated throughout the interior of the refrigerated structure.
• the presence of this passive, endothermic PCM and natural convective air flow maintains the reduced internal temperature of the refrigerated structure for an extended period of time.
• the predictability of the passive mode periods enables thermal recharge cycling of the mechanical refrigeration unit to be synchronized with "off-peak" hours when the cost of electricity is lower than during peak demand hours.
• the system as described is also useful in reducing or precluding excessive moisture within the refrigerated structure, which can be a significant problem.
• excess moisture results in the buildup of ice on the cooling coils, requiring the unit to be reversed in a defrost cycle wherein the coils are defrosted.
• defrosting may be required several times per day and may in aggregate take multiple hours per day, resulting in a thermally inefficient and energy inefficient process.
• the refrigerated structure is provided with additional insulating elements to reduce outside heat infiltration into the interior of the cold storage room/container from UV and radiant heat and convection.
• an exterior of the structure can be coated with a thermal reflective coating to reduce heat absorption from UV radiation.
• panels with high insulation values can be disposed within or on the walls, ceiling or floor of the cold storage structure to achieve optimum thermal storage efficiency.
• FIG. 1 illustrates that bimodal cold storage system 100 includes an enclosed refrigerated structure 101, which is a generally rectangular structure having an opening sealed by a door 102, and a mechanical refrigeration unit 103 mounted to refrigerated structure 101.
• refrigerated structure 101 preferably includes insulated walls and ceilings, and optionally, an insulated floor.
• refrigerated structure 100 can be, for example, a restaurant walk-in cooler or freezer, a cold storage warehouse, a cold storage shipping container, a refrigerated trailer (reefer), etc.
• the bimodal cold storage system 100 illustrated in FIG. 1 includes, as one of its thermal control modalities, a thermostatically controlled mechanical refrigeration unit 103 that monitors and regulates the temperature within an interior 104 of refrigerated structure 101 and the refrigerated contents and endothermic PCM disposed therein.
• mechanical refrigeration unit 103 employs a conventional evaporator/condenser system that produces chilled air and furthermore includes blowers or fans to forcefully discharge chilled, forced-air current(s) 112 into interior 104 to achieve rapid temperature control or recovery.
• Such mechanical refrigeration systems are well known and widely utilized to store and maintain goods within refrigerated structure 101 at reduced temperatures.
• the other thermal control modality employed by refrigerated structure 101 is achieved by compatibly deploying an endothermic PCM, such as an endothermic phase change material, in conjunction with the cycling, forced-air heat extraction mechanism to achieve substantially increased thermal extraction and absorption capacity, a more even thermal gradient distribution, and a reduced cycling of mechanical refrigeration unit 103.
• the endothermic PCM can be advantageously deployed within various PCM containers (e.g., overhead PCM tubes 105 and under-shelf PCM containers 106) supported by a rack system 110 within refrigerated structure 101.
• the particular endothermic PCM chosen is dependent on the desired temperature to be maintained within refrigerated structure 101.
• an endothermic PCM that reaches stasis at approximately -10° F (-23° C) is suitable for use in circumstances where the goods are to be maintained at or below freezing (i.e., 32° F or 0° C).
• endothermic PCMs having a higher stasis temperature can be utilized.
• Temperature ranges employed for common perishable goods include, for example, a temperature range between 32° F to 55° F (0° C to 13° C) for fruit, vegetables, beer, dairy products, pharmaceuticals, and the like, or between -32° F and -20° F (-36° C to -29° C) for frozen meat, ice cream, and the like.
• the endothermic PCM is preferably implemented utilizing a material, such as a water-based or organic-based PCM, that is non- hazardous and environmentally friendly.
• Rack system 110 which may be retrofitted within an existing refrigerated structure 101 without modification of the existing structure or originally installed in a new refrigerated structure 101, includes at least one (and possibly multiple) storage shelves 201 for supporting refrigerated goods.
• Storage shelf 201 is supported by adjustable height vertical supports 202, which may use, for example, perforated nested angled corner vertical supports secured by fasteners (e.g., nuts and bolts) to permit configuration (or reconfiguration) to a desired overall rack height.
• Overhead endothermic PCM tubes 105 are disposed on one or more horizontal support members 203, which are attached securely to height-adjustable vertical supports 202, for example, by welding, fasteners, etc.
• Vertical supports 202, and thus horizontal support members 203 and PCM tubes 105, are advantageously height-adjustable to allow optimal height placement of overhead endothermic PCM tubes 105.
• Optimal height placement of overhead endothermic PCM tubes 105 can depend on a number of factors, such as the maximum height clearance of the interior volume of refrigerated structure 101 (FIG. 1), the location of the forced-air flow ingress of mechanical refrigeration unit 103 (FIG. 1), the modular arrangement of rack system 110 (FIG. 1), the loading configuration of the cold storage goods, etc.
• PCM tubes 105 can be arranged with their long axes parallel to, orthogonal to, or in some other desired orientation to the forced-air flow path generated by mechanical refrigeration unit 103. Achieving the desired orientation of PCM tubes 105 to the forced-air flow path may also entail installation of PCM tubes 105 orthogonal to the long axis of rack systems 110 and bridging multiple rack systems 110.
• storage shelf 201 and horizontal support member 203 are depicted as being constructed using heavy duty wire mesh material. However, it should be appreciated that the selected material can vary between implementations. For example, solid surface and/or perforated surface may alternatively or additionally be employed. Moreover, other types of height-adjustable vertical shelf support systems such as telescopic vertical members or additional vertical support members can be employed without l niting the spirit and scope of the invention.
• storage shelf 201 is configured to support under-shelf PCM containers 106 by attachment (e.g., during initial construction or by retrofitting) of one or more under-shelf support brackets 205 to an underside of adjustable, storage shelf 201. With under-shelf support brackets 205 attached, additional under-shelf PCM containers 106 can be slidably installed under storage shelf 201.
• PCM containers 106 are formed of high-density polyethylene (HDPE) and have dimensions of 500 mm ⁇ 250 mm ⁇ 45 mm.
• HDPE high-density polyethylene
• PCM containers 106 are preferably sized to be mod xlarly reconfigurable to accommodate various storage shelf configurations.
• FIGs. 2B-2C illustrate that PCM containers 106 can be arranged in a first orientation as shown in FIG. 2B to fit a narrow storage shelf 201 (e.g., 18" x 48") or alternatively arranged in a second orientation as shown in FIG. 2C to fit a deeper storage shelf 201 (e.g., 24" 48").
• FIG. 3 there is illustrated a top plan view of an exemplary embodiment of a cold storage rack arrangement including four cold storage racks 110 in a 2 ⁇ 2 split configuration.
• the depicted arrangement may be suitable, for example, for a restaurant's walk-in cooler or freezer.
• overhead PCM tubes 105 are longitudinally disposed in alignment with the long axis of each cold storage rack 110 upon horizontal support members 203 (e.g., wire mesh) attached to adjustable height vertical supports 202.
• the quantity and arrangement of PCM tubes 105 disposed on horizontal support members 203 may vary depending upon the optimal volume and/or velocity of air flow passing between PCM tubes 105.
• the stability and rigidity of cold storage racks 110 is enhanced by one or more horizontal cross beams 204 coupled between cold storage racks 110.
• Horizontal cross beam(s) 204 preferably link cold storage racks 110 at their tops in order to preserve adequate headroom in a walk space 301 between cold storage racks 110.
• the width of walk space 301 which is defined by the length of horizontal cross beam(s) 204, is preferably of sufficient width to permit convenient access to goods stored on the various storage shelves 201 on either side of walk space 301. It should be appreciated that a variety of cold storage rack arrangements and horizontal cross beam lengths fall within the spirit and scope of the invention.
• Cold storage racks 110 enable the enclosing refrigerated structure in which they are disposed to benefit from the passive cooling provided by PCM tubes 105 (and optionally under- shelf PCM containers 106) without requiring any modification of the refrigerated structure or penetration of, or attachment to any of its interior surfaces.
• the passive cooling capacity of the refrigerated structure may optionally be further augmented by the attachment of additional PCM containers to one or more of the interior surfaces of the refrigerated structure.
• FIG.4 is a side elevation view of exemplary embodiment of a cold storage rack 110.
• FIG. 4 shows, via a cutaway view, overhead PCM tubes 105 disposed on horizontal support member 203, which is in turn attached securely to adjustable height vertical supports 202 for optimal height placement of overhead PCM tubes 105.
• ends of horizontal cross beam bracket 204 attach to adjustable height vertical supports 202, providing additional structural support.
• Structural members of cold storage racks 110 including vertical supports 202, shelf supports 400 and lateral braces 402, and may be implemented with bar, angle, channel, beam, square tube, round tube, etc. Although other materials may be employed, steel is presently preferred for the structural members of cold storage racks 110 due to steel's relatively low cost and high strength-to-weight ratio.
• cold storage rack 110 may optionally further incorporate PCM containers (e.g., PCM tubes 404) along or within one or more of its structural members to provide additional capacitive cooling capacity.
• PCM containers e.g., PCM tubes 404
• PCM containers may be secured to the structural members by ties, clamps, brackets or the like.
• additional attachment of the PCM containers to the structural members can be omitted.
• the exemplary management and control system preferably includes an electronic controller 520 communicatively coupled to multiple sensors within refrigerated structure 101. These sensors preferably include one or more PCM temperature sensors 502 that sense a PCM temperature in one or more PCM containers (e.g., overhead PCM tubes 105 or under-shelf PCM containers 106). In one embodiment shown in FIG.
• PCM temperature sensors 502 have a first probe 504 at or near a core region of a PCM tube 105 (or PCM container 106), and a second probe 506 at or near an outer region of a (possibly different) PCM tube 105 (or PCM container 106).
• the PCM temperature detected by probe 504 at the innermost point of overhead PCM tube 105 (or PCM container 106) lags behind the PCM temperature sensed by probe 506 near the inner surface of overhead PCM tube 105 (or PCM container 106) as the PCM changes phase from latent heat mode to sensible heat mode.
• Sensing temperature at multiple locations within the PCM can thus provide controller 520 a more accurate indication of the state of the PCM along its latent-to-sensible phase change curve (and sensible-to-latent phase change curve), where the goal of the controller 520 is to prevent complete conversion of the PCM from its latent heat mode to its sensible heat mode.
• the exemplary management and control system for cold storage system 100 preferably additionally includes one or more ambient condition sensors 510 within or associated with refrigerated structure 101.
• ambient condition sensors 510 may include an ambient temperature sensor providing temperature data indicative of the temperature of a representative location within the interior volume of refrigerated structure 101, as well as relative humidity and dew point sensors.
• ambient condition sensors may include a door sensor to sense the openings and closings of door 102.
• the ambient temperature will typically vary dynamically according to the heat transfer to and from the environment by numerous factors, the primary ones being operation of mechanical refrigeration unit 103, external ambient temperatures, and the number and duration of intrusions into refrigerated structure 101 by people and/or goods via door 102.
• the management and control system preferably further includes one or more goods sensors 512 that sense the temperature and/or other parameter of the goods within refrigerated structure 101.
• goods sensor(s) 512 may be placed on an exterior of one of the goods in refrigerated structure 101 or embedded within the goods.
• Controller 520 processes the sensor data received from sensors 502, 510 and 512 and, responsive thereto, controls mechanical refrigeration unit 103 in accordance with one or more control methodologies implemented alternatively or in combination.
• the control methodologies implemented by controller 520 can be configured to maintain the interior volume of refrigerated structure 101 within a desired temperature range while:
• controller 520 may optionally be further communicatively coupled to a communication interface 522, which communicates status information and/or alarms regarding cold storage system 100 to one or more remote locations via one or more wired or wireless packet switched or circuit switched communication networks.
• the status information and/or alarms can be communicated, for example, to a remote server computer, mobile phone, or pager of an operator of cold storage system 100, a service provider or service technician of the operator, or an electrical utility provider.
• the status information and/or alarms can be communicated, for example, in a textual message, numeric message and/or a data message, communicated, for example, in an email, short message service (SMS) message, phone call, page, HTTP message, or the like.
• SMS short message service
• controller 520 preferably initially activates mechanical refrigeration system 103 to produce chilled, forced-air current 112, which charges the endothermic PCM contained in overhead PCM tubes 105 and under-shelf PCM containers 106 and cools interior 104 of refrigerated structure 101.
• Controller 520 preferably operates mechanical refrigeration unit 103 in its active chill mode until the ambient temperature of interior 104 sensed by ambient temperature sensor 506 achieves at least a first threshold temperature, the endothermic PCM achieves stasis, as indicated by temperature sensor(s) 502. and the temperature of the goods indicated by goods sensor(s) 512 reaches a second threshold temperature. In response, controller 520 suspends or substantially reduces the operation of mechanical refrigeration unit 103.
• the endothermic (i.e., heat absorbing) characteristics of the PCM significantly extends the period of time over which the internal temperature of refrigerated structure 101 and the goods disposed therein will remain at or below the predetermined maximum temperature without having to operate mechanical refrigeration unit 103.
• Controller 520 senses this condition and operates mechanical refrigeration unit 103 in its active chill mode to recharge the PCM to its latent heat mode and maintain the goods temperature and ambient temperature of refrigerated structure 101 within desired temperature ranges.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Devices That Are Associated With Refrigeration Equipment (AREA)

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• 2011
  • 2011-05-26 BR BR112013030208A patent/BR112013030208A2/pt not_active IP Right Cessation
  • 2011-05-26 CA CA2836522A patent/CA2836522A1/en not_active Abandoned
  • 2011-05-26 JP JP2014512807A patent/JP2014515469A/ja active Pending
  • 2011-05-26 EP EP11865969.7A patent/EP2715257A1/en not_active Withdrawn
  • 2011-05-26 WO PCT/US2011/038212 patent/WO2012161718A1/en active Application Filing
• 2013
  • 2013-11-21 IL IL229555A patent/IL229555A0/en unknown

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