US20160109187A1

US20160109187A1 - Device for conserving and transporting fresh or frozen products, in particular for thermally insulated containers or the like

Info

Publication number: US20160109187A1
Application number: US14/888,653
Authority: US
Inventors: Pavel Houdek; Václav RAJTMAJER; Michal Kolda; Markéta KOPECKA; Michal Hegar; Lubos Forejt; Alberto Ghiraldi
Original assignee: Thermo King Corp
Current assignee: Thermo King Corp
Priority date: 2013-05-02
Filing date: 2014-05-02
Publication date: 2016-04-21
Also published as: US20160109186A1; CN105579797A; WO2014193600A1; EP2991916A1; CN105593134A; EP2992281A1; EP2992281A4; WO2015012932A1

Abstract

An apparatus for a thermally insulated container is disclosed. The apparatus includes one or more heat accumulators. Each of the thermal accumulators includes a plurality of longitudinal heat accumulation modules. Each of the longitudinal modules includes a casing forming a cavity therein. The cavity is configured to receive a phase change material. A first wall of the casing includes a substantially flat surface and a second wall includes a heat transfer enhanced surface portion. The longitudinal modules include a heat exchanger having at least a portion disposed within the cavity that is configured to supply a heat transfer fluid. The plurality of longitudinal heat accumulation modules are securely connected to each other and are in thermal communication with each other.

Description

FIELD

The present disclosure relates to a device for conserving and transporting fresh or frozen products, in particular for thermally insulated containers or the like.

BACKGROUND

Perishable goods, in particular foodstuffs, transported in containers need to be kept at temperatures compliant with ATP Standards. Examples of ATP standards include, but are not limited to, Class A, for “chilled” goods, and Class C, for “frozen” goods. For example, some containers can maintain temperatures between about −35° C. and about 21° C. Containers for perishable goods typically require high levels of conservation quality for the goods contained, guaranteeing thermal autonomy without intermediate recharging for periods of up to about 30 days.
Some containers are used to conserve and transport perishable goods:

- for up to 5-7 days primarily for short-sea, intermodal and offshore transport (hereinafter “short sea”);
- for up to 12-15 days for multimode transport, inland navigation, small and medium coastal shipping (hereinafter “mid sea”);
- up to 30 days for deep-sea transport (hereinafter “deep sea”).

Some containers are used to conserve and transport perishable goods over short and medium distances and in particular for offshore, onshore, intermodal and road transport, as well as short-sea shipping.
In known containers for perishable goods, a controlled-temperature system is maintained either using a heat accumulation system or electromechanical refrigeration systems powered electrically or using diesel generators.
However, the aforementioned technologies are not free from drawbacks.
Conventional heat accumulation systems have a number of unresolved technical problems described below.
a) Heat accumulation systems include box modules containing a phase change material subject to volumetric expansion caused by changes of state of the liquid. Box modules include volumes not filled with liquid in which a vacuum is created, to be used as expansion chambers. If the container is not perfectly level, the phase change material flows to one extremity, completely filling one part of the module, where unreciprocated expansion during the freezing process generates destructive pressures. Moreover, the presence at one end of tubular connectors with limited exchange surfaces results in the formation of significant pockets of liquid that subsequently freeze, causing localized destructive pressures and soon breaking the box modules.
b) The limited heat exchange capacity of known heat accumulation systems, which have flat surfaces, require most of the walls to be covered with the aforementioned box modules to obtain the necessary exchange surfaces, which increases the cost and unladen weight of the container. Being subject to significant stresses, the floor covering is particularly critical. Moreover, the limited heat exchange capacity may be compensated using systems to deliver more powerful thermal charging, which increases load losses and therefore energy consumption.
c) The arrangement of the box modules of known heat accumulation systems is thermally discontinuous, in particular in the upper corners of the containers exposed to solar radiation, where the main heat bridges are found. This results in significant heat flows with subsequent heat loads that are absorbed by the internal part of the heat accumulation system.
d) Although the heat load inside the container is not uniform, but concentrated on the roof by the effect of solar radiation, the heat flows caused by the lack of thermal continuity and the metabolic heat of the fruit and vegetables being kept inside the container, the dimensioning of the box elements is constant throughout the surfaces of the container. This uniformity reduces thermal autonomy since the accumulated capacity is exhausted preferably in the surfaces having a higher heat load with the consequent reduction in the thermal autonomy with equal overall accumulated capacity, and therefore a proportional increase in production costs, unladen weight and transport costs.
e) The box modules in known heat accumulation systems are applied to the ceiling of the container using the adhesion capacity of polyurethane to the surfaces of the modules, which tend to come unstuck under the effect of the weight, vibrations, and accelerations present during transportation and movement of the container, making the container unusable.
f) If made of aluminum, the box modules may not enable a salt solution to be used as the phase change material, since it is not compatible with aluminum and is in any case unstable over time.
g) Known accumulation systems cannot currently be used in containers for perishable products belonging to Class C, but are used to a limited extent for Class A products, where the heat loads are significantly lower.
h) An intrinsic feature of all transport modes, in particular medium and long distance, in which numerous pallets are loaded using mechanical devices, is the difficulty in cleaning and disinfecting and the introduction of significant bacterial loads during the loading phase, with the consequent exponential growth thereof, as well as the formation of botrytis and other molds, as well as the difficulty in generating and maintaining a modified atmosphere that minimizes the metabolism of the loaded products in the container.
Conventional technology based on electromechanical refrigeration depends on a continuous electrical or diesel-electric supply, with power supplied from the electricity network in the ports, on-board ship and diesel generators added to trucks for the road sections, and it has the following drawbacks:
a) The cooling unit is usually installed at one end of the container, and the usable sections for air inlet and outlet are very limited and consequently require high air circulation speeds, typically about 12 m/s, to obtain the required flow rates. Interaction between the high air circulation speed, the reduced usable sections, and the limited exchange surfaces of the evaporator of the cooling unit with the subsequent high AT between air and surface has the following drawbacks:

- high load losses with related high energy consumption;
- increase in the deterioration ratio of the products conserved due to the drying of the products themselves, even in high relative humidity and optimum temperatures;
- formation of ice on the surfaces of the evaporator of the cooling unit, and therefore the need for frequent defrosting;
- increased heat flow between the environment and inside the container, in particular around heat bridges, doors, etc. caused by the high air speed in contact with the walls, ceiling and upper corners.

b) high maintenance cost of cooling units, due to the need to use specialist staff in appropriate support centers.
c) inability to use cooling units when the transport unit is not fitted with diesel generators, in the case of field refrigeration following harvesting, and in cases where power is not available continuously.
d) cooling equipment does not enable the requirements related to optimum conservation of fresh products to be met, i.e. no ventilation, humidity above 95% and constant temperature at optimum values.
e). cooling capacity is limited to merely maintaining products and does not enable post-harvest refrigeration of the products.
f) the use of conventional refrigeration systems is not permitted for supplying offshore oil platforms or when travelling through long tunnels, for which the use of intrinsically safe electrical equipment is required, and therefore using complex procedures that require proximity deactivation beneath platforms and in tunnels, with the resultant discontinuity of refrigeration and increase in management costs.
g) high energy consumption of cooling units due both to the intrinsic features thereof (limited size of exchangers and therefore high AT and high load losses in the ventilation system with proportional energy consumption) and in severe usage conditions on board ships, where the temperature in the holds is high and there are limited air flows for cooling the condensers.

SUMMARY

The present disclosure provides an apparatus for conserving and transporting fresh or frozen products, in particular using thermally insulated containers or the like, that addresses the technical problems set out above, obviates the drawbacks and overcomes the limits of the prior art.
One objective of the present disclosure is to provide an apparatus for conserving and transporting fresh or frozen products that is able to maintain the required temperature for a given period of thermal autonomy without the need for energy after thermal charging, thereby enabling transport without electrical connection or power of any type.
Another objective of the present disclosure is to keep overall energy consumption below the solutions in the prior art.
A further objective of the disclosure is to provide optimum conditions for conserving fresh foodstuffs, including:

- an about constant temperature with an average hourly oscillation of less than about 0.2° C.;
- relative humidity greater than about 95%;
- no ventilation system.

The purpose and objectives set out above, and others set out in greater detail below, are achieved by an apparatus for conserving and transporting fresh or frozen products, in particular using thermally insulated containers or the like, including at least one heat accumulator associated with a respective internal wall of a container, and having a plurality of longitudinal heat accumulation modules, each of the modules having a casing delimiting a cavity that can contain a phase change material, the cavity containing a heat exchanger supplied with a heat exchange fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features are set out in the description of a non-exclusive embodiment of an apparatus for conserving and transporting fresh or frozen products, particularly in thermally insulated containers or the like, illustrated by way of non-limiting examples using the attached drawings, in which:

FIG. 1 is a schematic front view of an embodiment of an apparatus for conserving and transporting fresh or frozen products, according to the disclosure, installed in a container in which the heat flows are illustrated.

FIG. 2 is a frontal cross section of the apparatus in FIG. 1 through a central portion of the container.

FIG. 3 is a frontal cross section of the apparatus in FIG. 1 through a door-side portion of the container.

FIG. 4 is a magnified view of a portion of the apparatus in FIG. 1, specifically an upper corner of the container.

FIG. 5 is a magnified view of a portion of the apparatus in FIG. 4.

FIG. 6 is a plan view of a first embodiment of the apparatus in FIG. 1, installed in a container.

FIG. 7 is a plan view of a second embodiment of the apparatus in FIG. 1, installed in a container.

FIG. 8 is a plan view of a third embodiment of the apparatus in FIG. 1, installed in a container.

FIG. 9 is a cross section of a first type of heat accumulation module of the apparatus in FIG. 1.

FIG. 10 is a cross section of a second type of heat accumulation module of the apparatus in FIG. 1.

DETAILED DESCRIPTION

With reference to the Figures, the apparatus 1 for conserving and transporting fresh or frozen products, in particular using thermally insulated containers or the like, includes at least one heat accumulator 30, 32, 34, 36 associated with a respective internal wall 50, 52, 54 of a container 7. Each heat accumulator 30, 32, 34, 36 includes a plurality of longitudinal heat accumulation modules 90, 92, 94, each having a casing 11 delimiting a cavity 21 able to contain a phase change material. The cavity 21 contains a heat exchanger 19 supplied with a heat transfer fluid.
According to an embodiment, the heat accumulation modules 90, 92, 94 are mechanically and thermally connected to one another. The casing 11 also has a first wall 13 facing the internal face 50, 52, 54 of the container 7 with a substantially flat surface and a second wall 15 opposite the first wall 13 oriented towards the internal space 17 of the container 7 with an at least partially finned surface. In another embodiment, the second wall 15 can have a heat transfer enhanced surface portion that improves the heat transfer, similar to the at least partially finned surface. It is to be appreciated that this configuration is intended to be exemplary and that other configurations may also be possible.
As shown in FIGS. 9-10, the heat exchanger 19 includes two internally and externally finned ducts 190, 192 extending longitudinally inside the casing 11 that are connected, in the vicinity of the back end 110 of the casing 11, by a curved connector 194. The head end 112 of the casing 11 can include welded connectors between the ducts 190 and 192 and the heat exchange fluid inlet and outlet manifolds.
Moreover, the heat exchange fluid is discharged in the modules in FIG. 10 via the lower duct 192 and it is suctioned via the upper duct 190, creating a freezing sequence that pushes the phase change material upwards towards the filling material 27, which is used to absorb the expansion of the liquid.
In an embodiment, the arrangement of the evaporator can make it possible to keep the coldest part closer to the wall of the container, thereby limiting the undercooling of the surface of the module in the temperature pull-down phase of the fresh products, which can obviate the risk spoiling.
In an embodiment, the arrangement of the evaporator can make it possible to discharge and suction the heat transfer fluid from a single side, keeping the inlet and outlet manifolds in a rectilinear arrangement.
In an embodiment, the casing 11 may include, on the back end 110, a hole with an air vent 114 for releasing the oxygen released by the phase change material. In turn, the head end 112 may be provided with a hole with a screw cap 116 for filling up the phase change material.
Each thermal accumulator 30, 32, 34, 36 can cover substantially all of the surface of the internal wall 50, 52, 54 of the container 7, with which it is associated, providing a thermal filter distributed over the internal wall 50, 52, 54. This can help to limit the heat to be absorbed internally to the heat dissipated by the product and by the flow from the surfaces on which the heat filter is not applied.
As shown in FIGS. 1-3, the apparatus 1 includes a heat accumulator 30 associated with the ceiling 50 of the internal space 17 of the container 7, and two heat accumulators 32 associated respectively with the side walls 52 of the internal space 17. The ceiling heat accumulator 30 is supported on the two wall heat accumulators 32 and is mechanically and thermally connected to each of the two wall heat accumulators 32 by plates 25 welded to the ceiling heat accumulator 30 and respectively to each of the two wall heat accumulators 32. The apparatus 1 therefore includes an indivisible structure cooperating structurally with the structure of the container 7, in accordance with applicable regulations on conditions for carriage by sea, rail and road, as well as handling in port and railway terminals. In addition to the heat connection between the ceiling heat accumulator 30 and the wall heat accumulators 32, via the welded plates 25, it provides a continuous heat filter distributed over the ceiling 50 and the side walls 52 that absorbs the incoming heat from the walls and from the roof of the container 7, but also from the edges, which are an important source of heat flow.
Moreover, as shown in the apparatus 1 shown in FIGS. 1-3, each heat accumulator 30, 32 is associated with the respective internal wall 50, 52 such that the longitudinal direction of the heat accumulation modules 90, 92 of each heat accumulator 30, 32 is horizontal.
The heat accumulation modules 90, 92 are also advantageously hydraulically independent from one another such that any damage caused to a module only results in the loss of phase change material from that module.
In an embodiment, the modules 90, 92 are welded together such as to form an indivisible structure that is structurally strong and able to withstand its own weight and the acceleration caused by transportation and movement. The modules 90, 92 are also welded together such as to form a thermally indivisible structure in which the temperatures of the individual modules are uniform. As shown in FIG. 4, the casing 11 of each module 90, 92 has side walls 120 shaped such that each casing 11 fits mechanically with the contiguous modules.
In the embodiments of the apparatus 1 shown in FIGS. 6, 7, and 8, the heat accumulators 34, 36 are associated with the respective internal wall 50, 52 such that the longitudinal direction of the heat accumulation modules 94 is substantially vertical. Such embodiments may be suitable for containers 7 used where the internal height/length ratio of the container is greater than about 1.5:1, as can be the case in offshore, onshore, intermodal and road transport, as well as short sea shipping.
The embodiment of the apparatus 1 shown in FIG. 6 includes a single heat accumulator 34 associated with the back wall 54 of the container 7. The embodiment of the apparatus 1 shown in FIG. 7 includes a heat accumulator 34 associated with the back wall 54 and two heat accumulators 36 associated with the side walls 52. The embodiment of the apparatus 1 shown in FIG. 8 includes two heat accumulators 36 associated with the side walls 5. There is no ceiling heat accumulator in these embodiments. Similarly in this case, the vertical or horizontal arrangement can depend on the internal height/length ratio of the container.
In an embodiment, as shown in FIGS. 9-10, the casing 11 contains a filling material 27 able to absorb the expansion of the phase change material when it changes from a liquid to a solid state.
In an embodiment, a curved connector 194 is immersed in this filling material 27.
This filling material 27 can be closed-cell expanded polyethylene, according to an embodiment. The filling material 27 can have a total volume equal to about 10% of the volume of the phase change material, the expansion of which it is intended to absorb. In the horizontally arranged modules 90, 92, the filling material 27 is distributed around the upper wall 13 of each casing 11 and the back end 110 opposite the head end 112 where the heat transfer fluid is discharged, where the thickness can be about equal to the external radius, plus about 10%, of the curve described by the curved connector 194 connecting the two ducts 190, 192 of the heat exchanger 19. In an embodiment, the filling material 27 used to absorb the expansion at the end opposite the inlet/outlet of the heat transfer fluid, is applied at a thickness equal to at least about the radius of curvature of the connector 194 between the outlet duct 190 and the inlet duct 192 plus the variation in length caused by the positive or negative expansion of the heat exchanger 19 caused by the temperature difference. The presence of the aforementioned filling material 27 can prevent the formation at the back end 110 of pockets of phase change material in liquid phase, the subsequent freezing of which can be delayed by the limited exchange surface of the curve itself and by the heating caused by contact with the internal environment of the container 7, causes destructive pressures due to the sealing effect of the other completely frozen liquid, which can prevent the liquid contained in the back extremity 110 from draining
The volume of the phase change material can be substantially about 100% of the free volume inside the casing 11, less the filling material 27, according to an embodiment. This can, during thermal charging, distribute the volume increase of the phase change material caused by the change of state is throughout the heat accumulation module 90, 92, 94 and prevent expansion during the freezing phase because the phase change material cannot move predominantly to one end or the other, with the consequent destructive pressures.
In heat accumulators 34, 36 with vertical modules 94, if there is no filling material 27, the phase change material can occupy a volume equal to about 85—about 92% of the free volume inside the casing 11.
A layer of reflective material 40 may be inserted between the first wall 13 facing the internal face 50, 52, 54 of the container 7 and the internal face 50, 52, 54 itself, according to an embodiment. This layer of reflective material 40 may be, for example, Kapton® (available from E. I. du Pont de Nemours and Company) or the like. Indeed, a flat reflective surface can minimize the absorption of heat from the outside. In an embodiment, as shown in FIGS. 4-5, respectively a first layer of insulating material 41, the layer of reflective material 40 and a second layer of insulating material 42 are inserted between the first wall 13 facing the internal face 50, 52, 54 of the container 7 and the internal face 50, 52, 54 itself The layer of insulating material 41, 42 may be, for example, made of foam rubber.
Each of the modules 90, 92, 94 of a heat accumulator 30, 32, 34, 36 can be connected in parallel to the other modules 90, 92, 94 of the same heat accumulator 30, 32, 34, 36 by a straight outlet manifold 60 dimensioned internally such as to pre-equalize the flow rate of the heat transfer fluid in each of the heat exchangers 19, and by a straight inlet manifold 62 dimensioned internally such as to post-equalize the flow rate of the heat transfer fluid in each of the heat exchangers 19.
The outlet manifold 60 and the return manifold 62 can be divided into three sub-modules in which the usable section for the flow of heat transfer fluid is such that all of the heat exchangers 19 are supplied at about a uniform pressure. In particular, the three sub-modules of the outlet manifold 60 may have a gradually decreasing usable section, contrary to the three sub-modules of the return manifold 62, the usable section of which may gradually increase. In order to prevent preferential flow to the last module, a closed nozzle at least as long as the distance between the center lines of the heat exchangers 19 may be provided at the end of the outlet manifold 60.
The inlet and outlet direction of the heat transfer fluid respectively from the outlet manifold 60 and from the inlet manifold 62 is crossed to obtain uniform load losses.
In order to maintain similar temperatures in the different heat accumulators 30, 32, 34, 36 in a single apparatus 1 during the thermal charging phase, in the presence for example of different heat accumulation capacities and different heat loads between ceiling heat accumulators 50 or wall heat accumulators 52, each heat accumulator 30, 32, 34, 36 may include, for example, two systems in sequence and in particular:

- a valve for modulating the flow of heat transfer fluid appropriately calibrated to modulate the flow as a function of the accumulation capacity of the heat accumulator.
- a cut-off valve for cutting off the flow in the heat accumulator when the temperature thereof reaches a set point value, thereby enabling the heat transfer fluid to flow into other heat accumulators.

Each heat accumulator 30, 32, 34, 36 may include quick connectors for connection to heat load devices. In particular, the apparatus 1 may include a quick input connection for discharging the heat transfer fluid distributed to the different heat accumulators 30, 32, 34, 36 by a diffuser placed on the back wall, the three output sections of which are provided with solenoid cut-off valves and dimensioned and arranged such as to pre-equalize the circuits as a function of the quantity of heat to be absorbed to obtain the complete and simultaneous freezing of the phase change material in the different heat accumulators 30, 32, 34, 36, notwithstanding any different accumulation capacities. Furthermore, a quick connector connected to a manifold may be provided on the back wall for suction from the different heat accumulators 30, 32, 34, 36, the sections of which are dimensioned and arranged such as to post-equalize the circuits as a function of the quantity of heat to be absorbed to obtain the complete and simultaneous freezing of the phase change material.
Finally, a highly insulated panel may be placed on the back wall to mechanically protect the system for distributing and suctioning the heat transfer fluid and to thermally protect the load, to prevent the low temperatures of the ducts in charging phase from damaging the products, if fresh products are being stored.
The “heat exchange surface”/“total surface area” of the at least partially finned surface of the second wall 15 of each thermal accumulator 30, 32, 34, 36 may be between about 3:1 and about 6:1 depending on the required thermal load, i.e. the dimensions of the container 7 and the shipping conditions, according to an embodiment.
Specifically, thermal balancing may:
a) ensure thermal charging in parallel with uniform temperatures notwithstanding the different quantities of heat to be absorb such as to keep constant temperatures in the different heat accumulators 30, 32, 34, 36 that make up an apparatus 1, so as not to cause undercooling that would damage the fresh product;
b) guarantee the same thermal autonomy in components exposed to highly different heat loads resulting from the position of the heat accumulators 30, 32, 34, 36 in which the heat load of the ceiling heat accumulator 30 is caused by solar radiation on the roof and on the side edges of the container 7 and by direct absorption of the heat coming from the foodstuffs.
In relation to the foregoing, according to an embodiment, the apparatus 1 may include:

- a ceiling heat accumulator 30, the heat accumulation modules 90 of which have an actual width of about 170 mm, and the exchange surface of which is formed by fins about 10 mm high and about 5 mm apart, with a “heat exchange surface”/“total surface area” ratio of about 5:1;
- two wall heat accumulators 32, the modules 92 of which have an actual width of about 96 mm, and the exchange surface of which is formed by fins about 5 mm high and about 5 mm apart, with a “heat exchange surface”/“total surface area” ratio of about 3:1;

In another embodiment, the apparatus 1 may include two wall heat accumulators 32, the accumulation modules of which have an actual width of about 89 mm and the exchange surface of which is formed by fins about 12 mm tall and about 5 mm apart, with a “heat exchange surface”/“total surface area” ratio of about 6:1.
In an embodiment, the ceiling heat accumulator 30 and the wall heat accumulator 32 may include about 10 to about 12 modules 90, 92.
Depending on the class to which the container 7 belongs (A or C), the phase change material may include one of the following:

- hydrogen peroxide at concentrations of between about 0% and about 35%;
- n-decane.

Apparatuses 1 can use different concentrations of hydrogen peroxide for the ceiling heat accumulators 30 and the wall accumulators 32. Varying the percentage of oxygen in the hydrogen peroxide makes it possible to vary the solid-liquid transition temperature thereof.
The apparatus 1 may also include a system for compensating for external temperatures that are not compatible with the fresh products.
If the outside temperature is less than the temperature provided for in the regulations applicable to fresh products and in particular Class A in the ATP Standard, the thermal charger may also be used for heating the phase change material to temperatures up to about 10° C., the liquid using the sensible heat accumulated to maintain the required temperature inside the container 7.
The apparatus 1 may also include an internal cleaning and disinfecting system.
Pallets may be loaded under any conditions, for example in the field using mechanical devices, which introduce significant bacterial loads that, in high-humidity conditions, may subsequently grow. The internal cleaning and disinfecting system can include a system for producing and diffusing O₃, which can be blown through a quick connector located beside the quick connectors related to the heat transfer fluid and diffused using three suitable pipes advantageously arranged beneath the ceiling heat accumulator. Cleaning and disinfecting can be performed throughout the entire duration of the deep charging phase such as to preventatively destroy all bacterial residues and, once the products are loaded, it can be repeated during the product pull-down phase used to bring the products to optimum shipping temperature.
In an embodiment, the apparatus 1 may also include a system for modifying the internal atmosphere in order to significantly reduce the metabolism of the conserved products and the relative ethylene emissions, promoting and accelerating the formation of a natural modified atmosphere that helps to optimally conserved products. The blowing system can allow this modified atmosphere to be formed from the outset, which can further improve product conservation quality. Blowing is performed during the product pull-down phase by the thermal charger via a quick connector placed beside the quick connectors of the heat exchange fluid, and it is advantageously distributed using three ducts placed beneath the ceiling heat accumulator.
In the apparatus 1 for conserving and transporting fresh or frozen products, the internal temperature can be determined by the interaction between the temperature at which the phase change material previously cooled/heated by the thermal charger changes state, the external exchange surface of the heat accumulators, the internal exchange surface of the heat accumulators and the arrangement thereof within the container.
Operation of the phase change material is reversible and can be used both in hot climates where the fusion enthalpy of the phase change material previously frozen during thermal charging absorbs the heat coming from the outside, or in cold climates where the sensible heat of the phase change material previously heated during thermal charging keeps the internal temperature at values compliant with the ATP standards. Indeed, the thermal charger may be used both to cool and to heat the phase change material, depending on the product shipping and conservation requirements.
It has been determined in practice that the apparatus for conserving and transporting fresh or frozen products, particularly for thermally insulated containers or the like, according to the present disclosure, achieves the aforementioned purpose and the objectives as it enables product conservation and shipping conditions to be optimized in thermally insulated containers.
In an embodiment, the apparatus 1 can:

- provide a thermal filter distributed over the walls and edges of the container;
- standardize the internal temperature of the contain a space throughout the entire length thereof without using forced ventilation;
- generate natural convective motion able to prevent the formation of hotspots;
- have a total exchange surface that enables all of the heat to be absorbed by natural convection with a temperature range of less than about 4° C.;
- control the internal temperature through the interaction between the temperature at which the phase change material changes state, the external exchange surface of the heat accumulators, the internal exchange surface of the heat accumulators, and the arrangement thereof within the container;
- keep the internal relative humidity above about 95% without using humidifiers or introducing external air.

The apparatus for conserving and transporting fresh or frozen products, particularly for thermally insulated containers or the like, as described herein, may be subject to numerous modifications and variance all of which fall within the scope of the inventive concept.
Furthermore, all of the details may be replaced by other technically equivalent elements.
In practice, any materials may be used, as required, provided they are compatible with the specific use, as well as the contingent shapes and dimensions.

ASPECTS

It is noted that any of aspects 1-17 below can be combined with each other in any combination and can be combined with any of aspects 18-27 or 28-35. Further, any of aspects 18-27 and 28-35 can be combined with each other in any combination.
Aspect 1. An apparatus for conserving and transporting fresh or frozen products, in particular for thermally insulated containers and similar, comprising:
at least one heat accumulator associated with a respective internal wall of a container; and
a plurality of longitudinal heat accumulation modules, each of the modules having:

- a casing delimiting a cavity able to contain a phase change material, the cavity housing a heat exchanger supplied with a heat transfer fluid, wherein the heat accumulation modules are mechanically and thermally connected to one another, and the casing has a first wall facing the internal face of the container with a substantially flat surface and a second wall opposite the first wall oriented towards the internal space of the container with an at least partially finned surface.
  Aspect 2. The according to aspect 1, wherein the heat exchanger includes two internally and externally finned ducts extending longitudinally inside the casing that are connected in the vicinity of the back end of the casing by a curved connector, the head end of the casing being welded to the two ducts.
  Aspect 3. The apparatus according to any of aspects 1-2, wherein the heat exchanger is attached to the head end of the heat accumulation module, by the end with the inlet and outlet of the heat transfer fluid, to enable the heat accumulation fluid to flow freely inside the casing to the opposing back end.
  Aspect 4. The apparatus according to any of aspects 1-3, wherein the casing includes, on the back end, a hole with an air vent for releasing oxygen released by the phase change material.
  Aspect 5. The apparatus according to any of aspects 1-4, wherein each heat accumulator covers substantially all of the surface of the internal wall of the container with which it is associated, providing a heat filter distributed over the internal wall.
  Aspect 6. The apparatus according to any of aspects 1-5, wherein the heat accumulator is associated with the respective internal wall such that the longitudinal direction of the heat accumulation modules of the heat accumulator is horizontal.
  Aspect 7. The apparatus according to any of aspects 1-6, wherein the heat accumulator is associated with the respective internal wall such that the longitudinal direction of the heat accumulation modules of the heat accumulator is vertical.
  Aspect 8. The apparatus according to any of aspects 1-7, wherein the apparatus includes a heat accumulator associated with the ceiling of the internal space, and two heat accumulators associated respectively with the side walls of the internal space, the ceiling heat accumulator being supported on the two wall heat accumulators and being mechanically and thermally connected to each of the two wall heat accumulators by welded to the ceiling heat accumulator and respectively to each of the two wall heat accumulators, the apparatus forming an indivisible structure cooperating structurally with the structure of the container.
  Aspect 9. The apparatus according to any of aspects 1-8, wherein the casing contains a filling material able to absorb the expansion of the phase change material when it changes from a liquid to a solid state.
  Aspect 10. The apparatus according to any of aspects 1-9, the filling material is closed-cell expanded polyethylene, the filling material having a total volume equal to about 10% of the volume of the phase change material and being distributed on the upper part of the casing, and it is applied on the end opposite the outlet/inlet of the heat transfer fluid at a thickness equal to at least the radius of curvature of the curved connector between the outlet duct and the inlet duct plus the variation in length caused by the positive or negative expansion of the heat exchanger caused by the temperature difference.
  Aspect 11. The apparatus according to any of aspects 1-10, wherein a layer of reflective material is inserted between the first wall facing the internal face of the container and the internal face.
  Aspect 12. The apparatus according to any of aspects 1-11, wherein a first layer of insulating material, the layer of reflective material and a second layer of insulating material are respectively inserted between the first wall facing the internal face of the container and the internal face.
  Aspect 13. The apparatus according to any of aspects 1-12, wherein each of the modules of a heat accumulator is connected in parallel to the other modules of the same heat accumulator via a straight outlet manifold placed at one end and dimensioned internally such as to pre-equalize the flow rate of the heat transfer fluid in each of the heat exchangers and via a straight inlet manifold placed at the same end and dimensioned internally such as to post-equalize the flow rate of the heat transfer fluid in each of the heat exchangers, the incoming and outgoing direction of the heat exchange fluid from the outlet manifold and from the inlet manifold respectively being crossed to obtain uniform load losses.
  Aspect 14. The apparatus according to any of aspects 1-13, wherein each heat accumulator includes two systems in sequence for controlling the temperature in the thermal charging phase:
- a valve for modulating the flow of heat transfer fluid as a function of the accumulation capacity of the heat accumulator.
- a cut-off valve for cutting off the flow of heat transfer fluid in the heat accumulator when the temperature thereof reaches a set point value, causing the heat transfer fluid to flow into contiguous heat accumulators.
  Aspect 15. The apparatus according to any of aspects 1-14, wherein each heat accumulator includes quick connectors for connection to thermal charging devices.
  Aspect 16. The apparatus according to any of aspects 1-15, wherein the “heat exchange surface”/“total surface area” of the at least partially finned surface of the second wall is between about 3:1 and about 6:1.
  Aspect 17. The apparatus according to any of aspects 1-16, wherein the phase change material is one of the following:
- hydrogen peroxide at concentrations of between about 0% and about 35%; and
- n-decane.
  Aspect 18. A heat accumulator, comprising:

a plurality of longitudinal heat accumulation modules, each of the modules including:

- a casing forming a cavity therein, the cavity configured to receive a phase change material, the casing including a substantially flat surface wall portion and a heat transfer enhanced surface wall portion, and
- a heat exchanger having at least a portion disposed within the cavity, the heat exchanger configured to supply a heat transfer fluid;

wherein the plurality of longitudinal heat accumulation modules are securely connected to each other and are in thermal communication with each other.
Aspect 19. The heat accumulator according to aspect 18, wherein the casing includes: an aperture having an air vent configured to release oxygen released by the heat accumulator liquid.
Aspect 20. The heat accumulator according to any of aspects 18-19, wherein the heat exchanger is securely connected to a first end of the heat accumulation module.
Aspect 21. The heat accumulator according to any of aspects 18-20, wherein the casing includes a filling material configured to absorb the expansion of the phase change material during a state change from a liquid state to a solid state.
Aspect 22. The heat accumulator according to aspect 21, wherein the filling material is distributed on an upper portion of the casing, and wherein the filling material is disposed at a second end opposite a first end at which the heat exchanger is securely connected.
Aspect 23. The heat accumulator according to any of aspects 18-22, wherein each of the modules is connected in parallel fluid communication.
Aspect 24. The heat accumulator according to aspect 23, wherein each of the modules is connected in parallel fluid communication by an outlet manifold and an inlet manifold, wherein the inlet and outlet manifolds are configured to control a flow rate of the heat transfer fluid.
Aspect 25. The heat accumulator according to any of aspects 18-24, further comprising:
one or more quick connectors configured to connect the heat accumulator with a thermal charging device.
Aspect 26. The heat accumulator according to any of aspects 18-25, wherein the phase change material has a solid-liquid transition temperature between about 0° C. and about −32° C.
Aspect 27. The heat accumulator according to any of aspects 18-26, wherein the heat transfer enhanced surface wall portion includes one or more fins.
Aspect 28. A thermally insulated container, comprising:
one or more heat accumulators, each of the thermal accumulators including a plurality of longitudinal heat accumulation modules, each of the modules including:

- a casing forming a cavity therein, the cavity configured to receive a phase change material, wherein a first wall of the casing includes a substantially flat surface wall portion and a heat transfer enhanced surface wall portion, and
- a heat exchanger having at least a portion disposed within the cavity, the heat exchanger configured to supply a heat transfer fluid;
  wherein the plurality of longitudinal heat accumulation modules are securely connected to each other and are in thermal communication with each other.
  Aspect 29. The thermally insulated container according to aspect 28, wherein the one or more heat accumulators are disposed on an internal wall of the insulated container such that a longitudinal direction of the heat accumulation modules is about horizontal.
  Aspect 30. The thermally insulated container according to any of aspects 28-29, wherein the one or more heat accumulators are disposed on an internal wall of the insulated container such that a longitudinal direction of the heat accumulation modules is about vertical.
  Aspect 31. The thermally insulated container according to any of aspects 28-30, wherein the one or more heat accumulators are disposed on one or more of a ceiling and an internal wall of the insulated container.
  Aspect 32. The thermally insulated container according to any of aspects 28-31, wherein the one or more heat accumulators are disposed on a ceiling and at least one internal wall of the insulated container.
  Aspect 33. The thermally insulated container according to aspect 32, wherein the one or more heat accumulators are mechanically and thermally connected to the ceiling and the at least one internal wall.
  Aspect 34. The thermally insulated container according to any of aspects 28-33, wherein a reflective material is disposed between an internal wall and/or a ceiling of the insulated container and a surface of the one or more heat accumulators disposed thereon.
  Aspect 35. The thermally insulated container according to aspect 34, further comprising a first layer of insulating material disposed between the internal wall and/or ceiling and the reflective material and a second layer of insulating material disposed between the reflective material and the surface of the one or more heat accumulators disposed thereon.
  Aspect 36. The thermally insulated container according to aspect 28, wherein the heat transfer enhanced surface portion includes one or more fins.

The terminology used in this specification is intended to describe particular embodiments and is not intended to be limiting. The terms “a,” “an,” and “the” include the plural forms as well, unless clearly indicated otherwise. The terms “comprises” and/or “comprising,” when used in this specification, indicate the presence of the stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components.
With regard to the preceding description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size, and arrangement of parts without departing from the scope of the present disclosure.
The word “embodiment” as used within this specification may, but does not necessarily, refer to the same embodiment. This specification and the embodiments described are exemplary only. Other and further embodiments may be devised without departing from the basic scope thereof, with the true scope and spirit of the disclosure being indicated by the claims that follow.

Claims

What is claimed is:

1. A heat accumulator, comprising:

a casing forming a cavity therein, the cavity configured to receive a phase change material, the casing including a substantially flat surface wall portion and a heat transfer enhanced surface wall portion, and

a heat exchanger having at least a portion disposed within the cavity, the heat exchanger configured to supply a heat transfer fluid;

wherein the plurality of longitudinal heat accumulation modules are securely connected to each other and are in thermal communication with each other.

2. The heat accumulator according to claim 1, wherein the heat transfer enhanced surface wall portion includes one or more fins.

3. The heat accumulator according to claim 1, wherein the casing includes:

an aperture having an air vent configured to release oxygen released by the heat accumulator liquid.

4. The heat accumulator according to claim 1, wherein the heat exchanger is securely connected to a first end of the heat accumulation module.

5. The heat accumulator according to claim 1, wherein the casing includes a filling material configured to absorb the expansion of the phase change material during a state change from a liquid state to a solid state.

6. The heat accumulator according to claim 5, wherein the filling material is distributed on an upper portion of the casing, and wherein the filling material is disposed at a second end opposite a first end at which the heat exchanger is securely connected.

7. The heat accumulator according to claim 1, wherein each of the modules is connected in parallel fluid communication.

8. The heat accumulator according to claim 7, wherein each of the modules is connected in parallel fluid communication by an outlet manifold and an inlet manifold, wherein the inlet and outlet manifolds are configured to control a flow rate of the heat transfer fluid.

9. The heat accumulator according to claim 1, further comprising:

one or more quick connectors configured to connect the heat accumulator with a thermal charging device.

10. The heat accumulator according to claim 1, wherein the phase change material has a solid-liquid transition temperature between about 0° C. and about −32° C.

11. A thermally insulated container, comprising:

one or more heat accumulators, each of the thermal accumulators including a plurality of longitudinal heat accumulation modules, each of the modules including:

a casing forming a cavity therein, the cavity configured to receive a phase change material, wherein a first wall of the casing includes a substantially flat surface wall portion and a heat transfer enhanced surface wall portion, and

12. The thermally insulated container according to claim 11, wherein the one or more heat accumulators are disposed on an internal wall of the insulated container such that a longitudinal direction of the heat accumulation modules is about horizontal.

13. The thermally insulated container according to claim 11, wherein the one or more heat accumulators are disposed on an internal wall of the insulated container such that a longitudinal direction of the heat accumulation modules is about vertical.

14. The thermally insulated container according to claim 11, wherein the one or more heat accumulators are disposed on one or more of a ceiling and an internal wall of the insulated container.

15. The thermally insulated container according to claim 11, wherein the one or more heat accumulators are disposed on a ceiling and at least one internal wall of the insulated container.

16. The thermally insulated container according to claim 15, wherein the one or more heat accumulators are mechanically and thermally connected to the ceiling and the at least one internal wall.

17. The thermally insulated container according to claim 11, wherein a reflective material is disposed between an internal wall and/or a ceiling of the insulated container and a surface of the one or more heat accumulators disposed thereon.

18. The thermally insulated container according to claim 17, further comprising a first layer of insulating material disposed between the internal wall and/or ceiling and the reflective material and a second layer of insulating material disposed between the reflective material and the surface of the one or more heat accumulators disposed thereon.

19. The thermally insulated container according to claim 11, wherein the heat transfer enhanced surface wall portion includes one or more fins.