Title of Invention	METHOD AND DEVICE FOR OBTAINING A PREDETEREMINED TEMPERATURE TO BE MAINTAINED INSIDE A GOODS HOLDING SPACE IN A TRANSPORT CONTAINER
Abstract	A method and a device for better utilising latent cold in a cold producing material used for producing and upholding a pre-determined temperature inside a transport container or the like, where dry ice or a similar first phase change material having very low sublimation temperature is utilised. Inside the transport container is arranged a receptacle for such low sublimation temperature phase converting material, the said receptacle being provided with an enclosure having cavities for a second phase change material having a considerably higher melting point, the said cavities of the receptacle at least partially enclosing the inside of the receptacle, in which the converting material having the essentially lower melting point is received.

Title of Invention

METHOD AND DEVICE FOR OBTAINING A PREDETEREMINED TEMPERATURE TO BE MAINTAINED INSIDE A GOODS HOLDING SPACE IN A TRANSPORT CONTAINER

Abstract

A method and a device for better utilising latent cold in a cold producing material used for producing and upholding a pre-determined temperature inside a transport container or the like, where dry ice or a similar first phase change material having very low sublimation temperature is utilised. Inside the transport container is arranged a receptacle for such low sublimation temperature phase converting material, the said receptacle being provided with an enclosure having cavities for a second phase change material having a considerably higher melting point, the said cavities of the receptacle at least partially enclosing the inside of the receptacle, in which the converting material having the essentially lower melting point is received.

Full Text	WO 2006/031189 PCT/SE2005/001333 1 Method and device for ensuring maintained temperature inside a transport container or the like. FIELD OF THE INVENTION The invention relates to a method and a device for maintaining a temperature adapted to the goods to be transported inside a container forming an essentially closed volume or space by means of a refrigerant placed inside such container, wherein the refrigerant is a phase change material (PCM), having a very low evaporation temperature, intended to bring about and maintain a temperature adapted to the goods inside. BACKGROUND OF THE INVENTION It is known to place inside containers and the like receptacles more or less filled with dry ice, i.e. solid carbonic acid or similar PCM, which during the transportation time through the influence of the ambient surrounding temperature is brought to evaporate or sublimate, a process which is difficult to regulate. This result in high dry ice costs and an unsatisfactory function since the temperature inside the container hardly can be controlled as closely as desired. It is further known to arrange walls at transport boxes and the like provided with preferably closed spaces and fill said spaces with a phase change material (PCM) having a high melting temperature e.g. water.The boxes are before the loading thereof with goods placed in a space so cold that the phase change material is transformed into a solid state. During the transport, the heat necessary for the re-conversion will be collected from the ambient air passing through the box walls leaving the interior more or less unaffected. On long transports, some problems may occur in case the PCM is water WO 2006/031189 PCT/SE2005/00133.5 2 or freezing mixtures, since rather large volumes would be necessary in order to keep the desired low temperature inside the transport box interior. The reason why the first mentioned alternative/ i.e. to utilise known phase change materials of very low evaporating temperature type such as dry ice, liquid CO2, liquid nitrogen or the like as a matter of fact, is used rather sparsely, depends on the cost and on the fact that the extremely low temperatures often affect the goods transported in a negative way. A further drawback likewise important, is that in cases where the goods transported is not allowed to be colder than +/-0°C, the goods has to be insulated from the dry ice containing receptacle holding the evaporating dry ice, which results in a bad and lower utilisation of- the cold energy of the dry ice and increased handling costs.. AIM AND MOST IMPORTANT FEATURES OF THE INVENTION The new idea, behind the invention lies in utilising both a first phase change material (PCM) having a very low temperature of evaporation and a second phase change material having a melting point or temperature more closely adapted to the desired temperature of the goods or commodities to be transported. In this way also a lower ?-t is reached, resulting in a large reduction of the amount of dry ice necessary, a more secure, controllable function and essentially lower consumption and costs for dry ice or similar PCM. Behind the method according to this invention lies the requirement for making it possible to maintain a desired WO 2006/031189 PCT/SE2005/001333 3 temperature inside an insulated container or box for transport of temperature sensitive goods, e.g. cold stored or deep frozen foods. Today dry ice is often used for such transports and the dry ice placed in a receptacle placed in the upper part of the insulated transport container. As a result of the high A-t (100° C at 22° C outside or ambient temperature) a large amount of the latent "cold energy" of the dry ice will escape through the roof and the walls of the container. As heat searches for cold, the heat of the surroundings will quickly pass through the insulation of the container. A receptacle arranged according to this invention and adapted for dry ice or the like first phase change material, first PCM, has a bottom part, a top part such as a lid and, in some cases also walls made hollow or with internal spaces, adapted to contain a second phase change material, second PCM, which is in a liquid state at normal temperature and thus has a high melting and congealing temperature. The second phase change material, which can be water or water mixtures, is preferably filled into sealed bags or the like flexible receptacles, which in turn are placed into the hollow spaces of the bottom, lid and walls. Naturally, the phase change material may be filled directly into such hollow spaces, but the way of using bags or the like reduces or eliminates the risk for leakage. The lid of the receptacle is preferably sized in such a way that in can be placed inside the receptacle walls so that it rests upon the dry ice or the first PCM therein. There is, accordingly passages for the evaporated dry ice along the edges of the lid in that embodiment. Upon filling dry ice or first PCM into the intended part of the receptacle interior and mounting the receptacle inside the WO 2006/031189 PCT/SE2005/001333 4 transport container, the dry ice starts to evaporate or sublimate, i.e. transform from solid state into gas, and the resulting cold released will affect and transform to solid form the second phase change material inside the lid, bottom and in some cases walls of the receptacle, having the higher solidifying temperature When the container holding a temperature sensitive goods is subjected to heat from the surroundings during transport, the heat inside the transport container affects the outsides of the receptacle and seeks to transform into liquid state the phase change material inside the hollow spaces of the receptacle initially transformed into solid state and kept so by influence of the dry ice inside the receptacle. Gradually and finally the said second phase change material just mentioned, under influence of the ambient heat inside the container will be transformed into liquid state. The melting-is however retarded by the counter effect given by the dry ice as long as it lasts. As an advantage may be mentioned that the temperature inside the goods holding space of the container may be selected within a wide register, e.g. +8 , +/-0, -3, -12, -17, -21 or -32 °C according to intended temperature for the goods to be transported simply by selecting an appropriate water mixture. As mentioned above, ?-t for dry ice is 100° C at 22 °C outside or ambient temperature. With a second PCM having a melting temperature at -21°C the ?-t will be 43° C on an outside temperature at 22° C. With a second PCM having a melting point at +/-0°C, ?-t will be 22 at 22° C outside temperature. WO 2006/031189 PCT/SE2005/001333 5 An important feature of the invention is that the first PCM is surrounded by the second PCM at a high degree. This is the case even if only the bottom and the top parts are provided with spaces for the second PCM which thereby at least partially encloses the inside of the receptacle, in which the first PCM having the essentially lower melting point is received. The first PCM is then prevented to a high degree from direct influence from the surroundings. It should be noted in this context that the top and bottom parts not necessarily have to be positioned facing upwards and downwards respectively. Also other arrangements are possible even if that orientation is preferred. It is also preferred that also the wails of the receptacle are provided with spaces for second PCM. This way the direct influence from the surroundings on the first PCM is minimized. This aspect, where second PCM surrounds first PCM and the aggregate is positioned in a room to be refrigerated is in contrast to the background art, wherein no such solution is envisaged. This is very important as the consumption of the latent cold energy of the dry ice filled into the receptacle is directly proportional to the ?-t of the PCM used. BRIEF DESCRIPTION OF DRAWING In the following, the invention will be further explained with references to the attached drawing, which in its only figure diagrammatically shows a cross section through a receptacle according to the invention adapted to be placed inside a transport container. WO 2006/031189 PCT/SE2005/001331 6 DESCRIPTION OF EMBODIMENT The receptacle is as already mentioned intended to be placed inside a transport container or the like space, inside which temperature sensitive goods is arranged to be transported. The receptacle includes a bottom part 1, a top part in the form of a lid. 2 and side walls 3. The bottom and the lid and in some cases also the walls include inner and outer layers which define spaces 4 and 5, in some cases, particularly if the receptacle is high, possibly also at the positions indicated with 6. Inside the spaces 4, 5 and 6 are, in the example shown, inserted a number of bags or similar means 7 containing a. second PCM of a suitable type. Between the edges of the lid 2 and the insides of the walls 3 there are gaps 8. The lid 3, thus, is allowed to rest on top of the dry ice or first PCM arranged inside the receptacle and said gaps are arranged, to permit the escape of evaporated gas. Normally the entire receptacle is filled with dry ice, which results in a transformation into solid phase of the second PCM. As the said second PCM is transferred into solid state and kept so by influence of the dry ice, the receptacle as a whole will form a temperature regulating element inside the transport container or the like. Heat leaking into the container will be consumed for melting the PCM inside the bottom and lid and, if applicable, the walls, which procedure is delayed or counter-acted by remaining dry ice. The invention may be modified within the scope of the following claims. In one modification the first PCM is supplied in a separate box which can be positioned, e. g. by a sliding movement, into an outer receptacle having bottom, top WO 2006/031189 PCT/SE2005/001333 7 and possibly wall parts containing second PCM. After positioning that box this way, the opening in the outer receptacle could be covered with a lid or a wall portion including second PCM. As an alternative, the box could have at least one wall containing second PCM. Different first and second PCM materials could be utilized depending on the application and the requirements in the specific case. In particular the second PCM could be different mixtures including water, but also non-aqueous materials could also find their use with the invention. WO 2006/031189 PCT/SE2005/001333 8 CLAIMS 1. Method for obtaining and maintaining a predetermined temperature inside a space for transporting and/or storing of temperature sensitive or dependent goods, such as in a transport container or box, wherein as a. refrigerant agent or material is used dry ice or a similar phase change material (first PCM) having a low or extremely low temperature of sublimation/evaporation, characterised by the measure of providing a receptacle intended to receive the dry ice or like PCM with a bottom part (1) and a top part (2) with double layers, defining spaces (4, 5) for a second phase change material (second PCM) having considerably higher phase conversion temperature than that of the first PCM, said temperature also being adapted to a desired temperature range inside the container. 2. Method according to claim 1, characterised by arranging the receptacle with a top part (2) being a lid (2) of the receptacle. 3. Method according to claim 1 or 2, characterised by also arranging walls (3) of the receptacle with spaces (6) for receiving the second PCM. 4. Method according to claim 1, 2 or 3, characterised by inserting the PCM-material into the receptacle or a similar vessel positioned at an upper part of an inside space of the container when the goods is loaded. 5. Method according to any of the previous claims, characterised by the further neasures of inserting the WO 2006/031189 PCT/SE2005/001333 9 second PCM, e.g. water or a water mixture, in liquid state in bags or the like (7) into and essentially filling the spaces (4, 5, 6) inside the bottom part (1), the top part (2), and, where appropriate, the wails (3). 6. Method according to any of the previous claims, characterised by the measure of selecting a second phase change material composition for the said spaces (4, 5, 6} having solidifying and melting temperature, respectively, close to the desired temperature in the container. 7. Receptacle to be inserted into a transport container or box or the like space and adapted to receive refrigerant such as dry ice or the like phase change material (first PCM) having a low or very low melting or evaporation temperature, characterised in that the receptacle at least upwardly and downwardly being defined by a bottom part (1) and a. top part (2) having inside hollow spaces (4 and 5) for containing a phase change material (second PCM) having a far higher solidifying and melting temperature than the dry ice or the like first PCM. 8. Receptacle according to claim 7, characterised in, that the top part (2) is a lid (2). 9. Receptacle according to claim 7 or 8, characterised in, that it includes walls (3) having spaces (6) for receiving second PCM. 10. Receptacle according to any of the claims 7-9, characterised in, that the receptacle is formed by a bottom (2) and walls (3) forming a room for the reception of first PCM, and that a separable lid (2) is adapted to WO 2006/031189 PCT/SE2005/001333 10 an opening defined by the walls with play that allows evaporated gas to leave the first PCM, and is adapted to rest against the first PCM. 11. Receptacle according to any of the claims 7-1, characterised in that the second PCM inside the bottom part (1) , the top part (2) and possibly the walls (3) is enclosed into sealed bags or the like (7) . A method and a device for heller utilising latent cold in a cold producing material used for producing and upholding a pre-determined temperature inside a transport container or the like, where dry ice or a similar first phase change material having very low sublimation temperature is utilised. Inside the transport container is arranged a receptacle for such low sublimation temperature phase converting material, the said receptacle being provided with an enclosure having cavities for a second phase change material having a considerably higher melting point, the said cavities of the receptacle at least partially enclosing the inside of the receptacle, in which the converting material having the essentially lower melting point is received.

Full Text

WO 2006/031189 PCT/SE2005/001333
1
Method and device for ensuring maintained temperature inside a transport container or the like.
FIELD OF THE INVENTION
The invention relates to a method and a device for maintaining a temperature adapted to the goods to be transported inside a container forming an essentially closed volume or space by means of a refrigerant placed inside such container, wherein the refrigerant is a phase change material (PCM), having a very low evaporation temperature, intended to bring about and maintain a temperature adapted to the goods inside.
BACKGROUND OF THE INVENTION
It is known to place inside containers and the like receptacles more or less filled with dry ice, i.e. solid carbonic acid or similar PCM, which during the transportation time through the influence of the ambient surrounding temperature is brought to evaporate or sublimate, a process which is difficult to regulate. This result in high dry ice costs and an unsatisfactory function since the temperature inside the container hardly can be controlled as closely as desired.
It is further known to arrange walls at transport boxes and the like provided with preferably closed spaces and fill said spaces with a phase change material (PCM) having a high melting temperature e.g. water.The boxes are before the loading thereof with goods placed in a space so cold that the phase change material is transformed into a solid state. During the transport, the heat necessary for the re-conversion will be collected from the ambient air passing through the box walls leaving the interior more or less unaffected. On long transports, some problems may occur in case the PCM is water

WO 2006/031189 PCT/SE2005/00133.5
2
or freezing mixtures, since rather large volumes would be necessary in order to keep the desired low temperature inside the transport box interior.
The reason why the first mentioned alternative/ i.e. to utilise known phase change materials of very low evaporating temperature type such as dry ice, liquid CO2, liquid nitrogen or the like as a matter of fact, is used rather sparsely, depends on the cost and on the fact that the extremely low temperatures often affect the goods transported in a negative way.
A further drawback likewise important, is that in cases where the goods transported is not allowed to be colder than +/-0°C, the goods has to be insulated from the dry ice containing receptacle holding the evaporating dry ice, which results in a bad and lower utilisation of- the cold energy of the dry ice and increased handling costs..
AIM AND MOST IMPORTANT FEATURES OF THE INVENTION The new idea, behind the invention lies in utilising both a first phase change material (PCM) having a very low temperature of evaporation and a second phase change material having a melting point or temperature more closely adapted to the desired temperature of the goods or commodities to be transported. In this way also a lower ?-t is reached, resulting in a large reduction of the amount of dry ice necessary, a more secure, controllable function and essentially lower consumption and costs for dry ice or similar PCM.
Behind the method according to this invention lies the requirement for making it possible to maintain a desired

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temperature inside an insulated container or box for transport of temperature sensitive goods, e.g. cold stored or deep frozen foods. Today dry ice is often used for such transports and the dry ice placed in a receptacle placed in the upper part of the insulated transport container. As a result of the high A-t (100° C at 22° C outside or ambient temperature) a large amount of the latent "cold energy" of the dry ice will escape through the roof and the walls of the container. As heat searches for cold, the heat of the surroundings will quickly pass through the insulation of the container.
A receptacle arranged according to this invention and adapted for dry ice or the like first phase change material, first PCM, has a bottom part, a top part such as a lid and, in some cases also walls made hollow or with internal spaces, adapted to contain a second phase change material, second PCM, which is in a liquid state at normal temperature and thus has a high melting and congealing temperature. The second phase change material, which can be water or water mixtures, is preferably filled into sealed bags or the like flexible receptacles, which in turn are placed into the hollow spaces of the bottom, lid and walls. Naturally, the phase change material may be filled directly into such hollow spaces, but the way of using bags or the like reduces or eliminates the risk for leakage.
The lid of the receptacle is preferably sized in such a way that in can be placed inside the receptacle walls so that it rests upon the dry ice or the first PCM therein. There is, accordingly passages for the evaporated dry ice along the edges of the lid in that embodiment.
Upon filling dry ice or first PCM into the intended part of the receptacle interior and mounting the receptacle inside the

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transport container, the dry ice starts to evaporate or sublimate, i.e. transform from solid state into gas, and the resulting cold released will affect and transform to solid form the second phase change material inside the lid, bottom and in some cases walls of the receptacle, having the higher solidifying temperature
When the container holding a temperature sensitive goods is subjected to heat from the surroundings during transport, the heat inside the transport container affects the outsides of the receptacle and seeks to transform into liquid state the phase change material inside the hollow spaces of the receptacle initially transformed into solid state and kept so by influence of the dry ice inside the receptacle. Gradually and finally the said second phase change material just mentioned, under influence of the ambient heat inside the container will be transformed into liquid state. The melting-is however retarded by the counter effect given by the dry ice as long as it lasts.
As an advantage may be mentioned that the temperature inside the goods holding space of the container may be selected within a wide register, e.g. +8 , +/-0, -3, -12, -17, -21 or -32 °C according to intended temperature for the goods to be transported simply by selecting an appropriate water mixture.
As mentioned above, ?-t for dry ice is 100° C at 22 °C outside or ambient temperature. With a second PCM having a melting temperature at -21°C the ?-t will be 43° C on an outside temperature at 22° C. With a second PCM having a melting point at +/-0°C, ?-t will be 22 at 22° C outside temperature.

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An important feature of the invention is that the first PCM is surrounded by the second PCM at a high degree. This is the case even if only the bottom and the top parts are provided with spaces for the second PCM which thereby at least partially encloses the inside of the receptacle, in which the first PCM having the essentially lower melting point is received. The first PCM is then prevented to a high degree from direct influence from the surroundings. It should be noted in this context that the top and bottom parts not necessarily have to be positioned facing upwards and downwards respectively. Also other arrangements are possible even if that orientation is preferred.
It is also preferred that also the wails of the receptacle are provided with spaces for second PCM. This way the direct influence from the surroundings on the first PCM is minimized.
This aspect, where second PCM surrounds first PCM and the aggregate is positioned in a room to be refrigerated is in contrast to the background art, wherein no such solution is envisaged.
This is very important as the consumption of the latent cold energy of the dry ice filled into the receptacle is directly proportional to the ?-t of the PCM used.
BRIEF DESCRIPTION OF DRAWING
In the following, the invention will be further explained with references to the attached drawing, which in its only figure diagrammatically shows a cross section through a receptacle according to the invention adapted to be placed inside a transport container.

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DESCRIPTION OF EMBODIMENT
The receptacle is as already mentioned intended to be placed inside a transport container or the like space, inside which temperature sensitive goods is arranged to be transported.
The receptacle includes a bottom part 1, a top part in the form of a lid. 2 and side walls 3. The bottom and the lid and in some cases also the walls include inner and outer layers which define spaces 4 and 5, in some cases, particularly if the receptacle is high, possibly also at the positions indicated with 6. Inside the spaces 4, 5 and 6 are, in the example shown, inserted a number of bags or similar means 7 containing a. second PCM of a suitable type.
Between the edges of the lid 2 and the insides of the walls 3 there are gaps 8. The lid 3, thus, is allowed to rest on top of the dry ice or first PCM arranged inside the receptacle and said gaps are arranged, to permit the escape of evaporated gas.
Normally the entire receptacle is filled with dry ice, which results in a transformation into solid phase of the second PCM. As the said second PCM is transferred into solid state and kept so by influence of the dry ice, the receptacle as a whole will form a temperature regulating element inside the transport container or the like. Heat leaking into the container will be consumed for melting the PCM inside the bottom and lid and, if applicable, the walls, which procedure is delayed or counter-acted by remaining dry ice.
The invention may be modified within the scope of the following claims. In one modification the first PCM is supplied in a separate box which can be positioned, e. g. by a sliding movement, into an outer receptacle having bottom, top

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and possibly wall parts containing second PCM. After positioning that box this way, the opening in the outer receptacle could be covered with a lid or a wall portion including second PCM. As an alternative, the box could have at least one wall containing second PCM.
Different first and second PCM materials could be utilized depending on the application and the requirements in the specific case. In particular the second PCM could be different mixtures including water, but also non-aqueous materials could also find their use with the invention.

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CLAIMS
1. Method for obtaining and maintaining a predetermined
temperature inside a space for transporting and/or
storing of temperature sensitive or dependent goods, such
as in a transport container or box, wherein as a.
refrigerant agent or material is used dry ice or a
similar phase change material (first PCM) having a low or
extremely low temperature of sublimation/evaporation,
characterised by the measure of providing a receptacle
intended to receive the dry ice or like PCM with a bottom
part (1) and a top part (2) with double layers, defining
spaces (4, 5) for a second phase change material (second
PCM) having considerably higher phase conversion
temperature than that of the first PCM, said temperature
also being adapted to a desired temperature range inside
the container.
2. Method according to claim 1, characterised by arranging
the receptacle with a top part (2) being a lid (2) of the
receptacle.
3. Method according to claim 1 or 2, characterised by also
arranging walls (3) of the receptacle with spaces (6) for
receiving the second PCM.

4. Method according to claim 1, 2 or 3, characterised by
inserting the PCM-material into the receptacle or a
similar vessel positioned at an upper part of an inside
space of the container when the goods is loaded.
5. Method according to any of the previous claims,
characterised by the further neasures of inserting the

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second PCM, e.g. water or a water mixture, in liquid state in bags or the like (7) into and essentially filling the spaces (4, 5, 6) inside the bottom part (1), the top part (2), and, where appropriate, the wails (3).
6. Method according to any of the previous claims,
characterised by the measure of selecting a second phase
change material composition for the said spaces (4, 5, 6}
having solidifying and melting temperature, respectively,
close to the desired temperature in the container.
7. Receptacle to be inserted into a transport container or
box or the like space and adapted to receive refrigerant
such as dry ice or the like phase change material (first
PCM) having a low or very low melting or evaporation
temperature, characterised in that the receptacle at
least upwardly and downwardly being defined by a bottom
part (1) and a. top part (2) having inside hollow spaces
(4 and 5) for containing a phase change material (second PCM) having a far higher solidifying and melting temperature than the dry ice or the like first PCM.
8. Receptacle according to claim 7, characterised in, that
the top part (2) is a lid (2).
9. Receptacle according to claim 7 or 8, characterised in,
that it includes walls (3) having spaces (6) for
receiving second PCM.
10. Receptacle according to any of the claims 7-9,
characterised in, that the receptacle is formed by a
bottom (2) and walls (3) forming a room for the reception
of first PCM, and that a separable lid (2) is adapted to

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an opening defined by the walls with play that allows evaporated gas to leave the first PCM, and is adapted to rest against the first PCM.
11. Receptacle according to any of the claims 7-1, characterised in that the second PCM inside the bottom part (1) , the top part (2) and possibly the walls (3) is enclosed into sealed bags or the like (7) .
A method and a device for heller utilising latent cold in a cold producing material used for producing and upholding a pre-determined temperature inside a transport container or the like, where dry ice or a similar first phase change material having very low sublimation temperature is utilised. Inside the transport container is arranged a receptacle for such low sublimation temperature phase converting material, the said receptacle being provided with an enclosure having cavities for a second phase change material having a considerably higher melting point, the said cavities of the receptacle at least partially enclosing the inside of the receptacle, in which the converting material having the essentially lower melting point is received.

METHOD AND DEVICE FOR OBTAINING A PREDETEREMINED TEMPERATURE TO BE MAINTAINED INSIDE A GOODS HOLDING SPACE IN A TRANSPORT CONTAINER

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