Patent Publication Number: US-10309712-B2

Title: Cooling device

Description:
The invention relates to a cooling device, in particular a freezer or cool box for storing and transport of medical products such as vaccines or blood products. 
     Such cooling devices can be employed in remote areas, for example in developing countries, where a stable and safe continuous energy supply, for example via a power supply system, cannot be ensured. Just in these areas, where often also extreme climatic conditions prevail, an uninterrupted cold chain for food and in particular medical products, such as for example vaccines or blood products, however is indispensable. In particular, handling and storing of such products under the manufacturer&#39;s conditions to be met to achieve the usability and efficacy of the products is often difficult, what is considered to be one of the causes for the extremely poor living conditions of the people living there and significantly contributes to the high mortality rate. 
     Therefore, the World Health Organization (WHO) has made a catalogue with threshold criteria, which have to be fulfilled by the used cooling equipment for the transport and storage of medical products. Thus, for the transport for short routes thus in particular insulation boxes with ice bags, or so-called freeze packs have established with which the required cooling of the stored substances at least during the short transport can be ensured. For the storage of medical products more stringent requirements arise. So, the cooling temperature in particular for various vaccines and blood products must not be higher than +8° C. and not less than +2° C. Further, even upon failure of the power supply sufficient cooling must be ensured. Thus, in particular electrical cooling apparatus with and without cooling elements, or battery-driven cooling elements are possible. Here, it has been found to be practicable to generate the power required for operation in a photovoltaic manner since the solar insolation in most developing countries is sufficiently high throughout the year. 
     The failure of power supply, but also the requirement to be able to transport medical products in cold boxes over land, for example requires the production of ice with which the cooling goods can be cooled during the energy-free time or transport, respectively. For example, such power failures regularly occur with a photovoltaically operated cooling device during the solar insolation-free time (e. g. at night or in case of clouds). However, such failures may also occur with mains operation, since in particular in remote areas a stable power supply by no means is certain. Also, with such mains-operated cooling devices the so-called “hold-over” time of generally 20 hours is very low. This is the period within which the internal temperature rises by a maximum of 10° C. at an ambient temperature of 32° C. 
     In order to effectively freeze water often a temperature is required that is well below under 0° C. to ensure a sufficient cooling of the water, and thus a fast ice formation. For example, there are known cooling devices having a freezing room to produce ice bags or freeze packs in addition to a cooling space for the products to be stored. The ice bags or freeze packs may be used to fill in the energy-free time. 
     To freeze the water and/or the ice bags a cooling circuit can be used. Due to the limited availability of electric energy it is required that the freezing process is performed with a minimum expenditure of energy and time. Since the cooling devices are to be transportable, moreover their handiness must be ensured. For example, external dimension and weight should be minimized. 
     Thus, it is an object of the present invention to provide a cooling device providing a reduced expenditure of energy and time for a freezing process and at the same time complies with the prescribed criteria and targets. Moreover, it is an object of the present invention to provide a cooling device having a compact, reliable and simple construction. 
     The object of the invention is solved by the subject matter of the independent claim. Preferred optional embodiments and specific aspects of the invention result from the dependent claims, the drawings, and the following description. 
     In accordance with embodiments of the present disclosure there is suggested a cooling device, in particular a freezer. The cooling device comprises a cooling circuit having a compressor, at least one evaporator and a condenser; a space for cooling goods that can be closed at its upper surface; and a coolant reservoir at least partially surrounding an upper region of the space for cooling goods, wherein the at least one evaporator is disposed in the coolant reservoir, and wherein the at least one evaporator at least partially surrounds the upper region of the space for cooling goods. 
     In accordance with the embodiments described in the following an expenditure of energy and time for a freezing process can be reduced and at the same time the prescribed criteria and targets can be complied with. Moreover, the cooling device according to the invention has a compact, reliable, and simple construction. In particular, by disposing the at least one evaporator of the cooling circuit in the coolant reservoir, i.e. in the cooling liquid, for example in the water, a good energy flow between the cooling liquid and the at least one evaporator can be ensured which allows a rapid freezing of the cooling liquid at a reduced expenditure of energy. In other words, in accordance with embodiments it is possible to quickly and efficiently produce ice. The ice can also be referred to as “icelining”. Moreover, by providing the coolant reservoir no additional cooling space for freezing or storing ice bags or freeze packs is needed whereby the cooling device can be made compact and simple. 
     In accordance with some embodiments that can be combined with other embodiments described here the at least one evaporator is disposed in a lower region of the coolant reservoir. For example, the at least one evaporator is designed to freeze coolant, in particular water, starting from a lower region of the coolant reservoir towards an upper region of the coolant reservoir. In this way, the coolant can expand without resistance in the freezing process, whereby a damage of the coolant reservoir in the freezing process by the increase in volume can be prevented. For example, the coolant reservoir can be an upwardly open coolant reservoir, so that the coolant can upwardly expand in freezing without resistance. The upwardly open coolant reservoir can be closed by a lid for example the same lid with which also the upper surface of the space for cooling goods can be closed. Alternatively, the coolant reservoir may also be formed of a partially closed container made in one piece in which the at least one evaporator is disposed. 
     In some implementations the at least one evaporator is formed as a tubular evaporator. For example, the at least one evaporator can comprise at least one loop and in particular three or more loops. In this way, the at least one evaporator can be disposed in the coolant reservoir in a simple manner and with little effort, so that the at least one evaporator is looped around the region of the space for cooling goods. By the tubular evaporator that can have one or more loops the coolant can be uniformly cooled and frozen in the coolant reservoir. It is also conceivable that the evaporator formed as a tubular evaporator is disposed in the coolant reservoir such that it has an inclination. 
     In accordance with some embodiments that can be combined with other embodiments described here the coolant reservoir at least partially or even completely surrounds the upper region, and in particular an upper circumferential region of the space for cooling goods. In this way, the space for cooling goods or the cooling goods, respectively, can be cooled uniformly and from all sides, so that a temperature distribution within the space for cooling goods is homogenous. This is of particular advantage for storing medical products, since for example the whole vaccine or all of the blood conserves are substantially exposed to the same temperature. 
     In accordance with some embodiments that can be combined with other embodiments described here the upper region of the space for cooling goods, that is at least partially or completely surrounded by the coolant reservoir, corresponds to 10% to 90% of a height of the space for cooling goods, and in particular 40% to 60% of the height of the space for cooling goods. In this way, on the one hand a sufficient cooling of the space for cooling goods can be ensured and on the other hand the weight of the cooling device can be reduced, since the space for cooling goods is not completely, i.e. not over its entire height, surrounded by the coolant reservoir or embedded or immersed therein. 
     In accordance with some embodiments that can be combined with other embodiments described here the coolant reservoir is upwardly open or closed. In some implementations the coolant reservoir has a U-shaped cross section. For example, the U-shaped cross section can be upwardly open, so that the coolant can upwardly expand during freezing without any resistance. 
     In accordance with some embodiments that can be combined with other embodiments described here the coolant reservoir comprises external walls that are formed at least partially wavy or corrugated. For example, the external walls of the coolant reservoir may be formed wavy or corrugated in a direction perpendicular to the height direction of the space for cooling goods. In this way, the cooling device, and in particular the coolant reservoir, can be provided with an increased stability. 
     In some embodiments that can be combined with other embodiments described here the cooling device comprises a cooling space having four cooling space sidewalls, a cooling space base and a lid designed to close the space for cooling goods at its upper surface. For example, a receiving space or cavity can be formed between the four cooling space sidewalls of the cooling space and the external walls of the space for cooling goods, wherein the coolant reservoir can be disposed in said receiving space. The receiving space can at least partially be filled with air and/or with an insulation material, for example an insulating foam. By the insulation material a thermal energy flow between the coolant reservoir and the space for cooling goods can be adjusted or influenced. 
     Typically, the coolant reservoir is spaced from the four cooling space sidewalls of the cooling space and/or the external walls of the space for cooling goods. By providing a distance between the space for cooling goods and the coolant reservoir a predetermined thermal insulation between the space for cooling goods and the coolant reservoir can be provided. In some embodiments the distance is selected such that a predetermined heat exchange between the space for cooling goods and the coolant reservoir can occur. In this way, it can for example be prevented that the interior and the walls of the space for cooling goods fall to a temperature below 2° C. 
     In accordance with some embodiments that can be combined with other embodiments described here the cooling device is designed to provide a temperature within a particular range of especially +2 to +8° C. in the space for cooling goods, for example if an electric primary cooling circuit of the cooling device is not functional due to a power interruption (e.g. at night, in case of clouds or power failure). For example, this can be done by a suitable design of the coolant circuit, the volume of the coolant reservoir, the height of the coolant reservoir, the type and amount of the insulation material in the receiving space, the distance between the space for cooling goods and the coolant reservoir and/or a combination of said measures. Optionally, further a heating device may be provided that is designed to supply heat to the space for cooling goods. In this way, for example it can be prevented that the interior of the space for cooling goods falls to a temperature of below 2° C. 
     Typically, the cooling device is a freezer for storing and transport of medical products, such as for example vaccines or blood products. Such freezers can be advantageously employed in remote areas, for example in developing countries, where a stable and safe continuous energy supply, for example via a power supply system, cannot be ensured. 
    
    
     
       Examples of the invention are illustrated in the drawings and are described in detail in the following. Here: 
         FIG. 1  shows a schematic illustration of a cooling device in accordance with embodiments of the present disclosure, 
         FIG. 2  shows a schematic sectional view of the cooling device of  FIG. 1  in accordance with embodiments of the present disclosure, 
         FIG. 3  shows a schematic illustration of a cooling circuit of a cooling device in accordance with embodiments of the disclosure, 
         FIG. 4  shows a schematic sectional view of a cooling device having a tubular evaporator with loops in accordance with embodiments of the present disclosure, 
         FIG. 5  shows a schematic illustration of a coolant reservoir, 
         FIG. 6  shows a transparent view of the coolant reservoir shown in  FIG. 5 . 
     
    
    
     In the following, unless stated otherwise, the same reference symbols are used for identical and equivalent elements. 
       FIG. 1  shows a schematic illustration of a cooling device  100 . 
     The cooling device  100  comprises a cooling circuit  200  having a compressor  210 , at least one evaporator  220 , and a condenser (not shown), a space for cooling goods  300  that can be closed at its upper surface, and a coolant reservoir  400  that at least partially surrounds an upper region of the space for cooling goods  300 . The evaporator  220  is disposed in the coolant reservoir  400  and at least partially surrounds the upper region of the space for cooling goods  300 . Typically, the coolant reservoir  400  is a container or a basin suitable to receive a coolant or cooling liquid (not shown), for example water. The space for cooling goods  300  is provided and designed to receive and store cooling goods, for example medical products. 
     A failure of power supply as is regularly occurring with a photovoltaically operated cooling device during the solar insolation-free time, e.g. at night or in case of clouds, but also the requirement to be able to transport medical products in the cooling device over land, for example requires the production of ice with which the cooling goods in the space for cooling goods  300  can be cooled during the energy-free time or transport, respectively. 
     By disposing the at least one evaporator  220  of the cooling circuit directly in the coolant reservoir  400 , i.e. in the cooling liquid, for example water, a good energy flow between the coolant and the at least one evaporator  220  can be ensured, which allows a rapid freezing of the coolant at reduced energy expenditure, see also  FIG. 5  and  FIG. 6 . In other words, according to the invention ice can quickly and efficiently be produced. The ice can also be referred to as “icelining”. 
     Moreover, by providing the coolant reservoir  400  no additional cooling space for freezing or storing ice bags or freeze packs is needed, whereby the cooling device  100  can be produced in a compact, simple, and inexpensive manner. Also, the ice bags or freeze packs themselves are not needed which further simplifies a construction of the cooling device  100  and reduces production costs, in particular since less moveable parts are present. 
     The coolant reservoir  400  and/or the at least one evaporator  220  do(es) not extend beyond the upper surface or the upper edge of the cooling space  300 . In this way, the cooling device  100  can be built compactly. In particular, the height of the cooling device  100  can be minimized, since the at least one evaporator  220  surrounds the upper region of the space for cooling goods  300  and thus, is not disposed above or below the space for cooling goods  300 . 
     The compressor  210  and/or the condenser may be disposed on one side of the space for cooling goods  300 . This allows a compact assembly. In particular, by the lateral arrangement of the compressor  210  and/or the condenser the total height of the cooling device  100  can be further reduced and the influence of the unavoidable heat generation of the cooling device on the cooling space is minimized. 
     Here, the cooling circuit is designed as a refrigerating machine that uses a thermodynamic cycle. In such a thermodynamic cycle by supplying external energy, for example by the compressor, heat below the ambient temperature, for example of the coolant to be frozen, can be absorbed at one point and evolved at a higher temperature at another point, for example at the condenser. 
     The space for cooling goods  300  according to the embodiments described here has the upper surface and a lower surface. The terms “upper surface” and “lower surface” relate to opposite sides of the space for cooling goods  300  or the cooling device  100 , respectively. The upper surface and the lower surface are connected by sidewalls. The lower surface may also be referred to as “base”. The upper surface has an opening through which the space for cooling goods  300  is accessible from the outside. The opening can be closed, and in particular can be closed by a lid (not shown). 
       FIG. 2  shows a schematic sectional view of the cooling device  100  of  FIG. 1 . 
     The evaporator  220  is designed to freeze the coolant starting from a lower region of the coolant reservoir  400  towards an upper region of the coolant reservoir  400 . In other words, the coolant freezes from the lower surface of the space for cooling goods  300  or the cooling device  100 , respectively, towards the upper surface of the space for cooling goods  300  or the cooling device  100 , respectively, indicated by the arrow A. In this way, the coolant can expand without any resistance during the freezing process, whereby damage of the coolant reservoir  400  or the cooling device  100 , respectively, is prevented. 
     The evaporator  220  may be disposed in a lower region of the coolant reservoir  400  to freeze the coolant starting from the lower region of the coolant reservoir  400  towards the upper region of the coolant reservoir  400 . As can be seen for example in  FIG. 2 , the evaporator  220  is disposed in the lower two thirds or a lower half of the coolant reservoir  400 . Typically, the at least one evaporator  220  is disposed in the coolant reservoir  400  such that the at least one evaporator  220  is at least partially, and in particular completely, surrounded by the coolant or immersed into the coolant, respectively. 
     The coolant reservoir  400  may have a volume that can take up a predetermined amount of the coolant. Here, less than 90%, and in particular between 50% and 90% of the volume of the coolant reservoir  400  can be filled with the coolant. In other words, the coolant reservoir  400  can be filled with the coolant up to a certain height that is smaller than the total height of the coolant reservoir  400 . In this way, during freezing the coolant can expand upwardly without escaping from the coolant reservoir  400 . 
     As can be seen in particular in  FIG. 5  and  FIG. 6  the coolant reservoir  400  is formed upwardly open. However, it is also conceivable to form the coolant reservoir  400  upwardly closed. If the coolant reservoir  400  is upwardly closed, in accordance with some implementations less than 90%, and in particular between 50% and 90% of the volume of the coolant reservoir  400  can be filled with the coolant, whereby damage of the coolant reservoir  400  or the cooling device  100 , respectively, can be prevented. 
     The coolant reservoir  400  has a U-shaped cross section, as is exemplarily shown in  FIG. 2 . The U-shaped cross section is upwardly open, so that the coolant during freezing can expand upwardly without any resistance, whereby damage of the coolant reservoir  400  or the cooling device  100 , respectively, is prevented. Typically, the upwardly open coolant reservoir  400  can be closed by a lid (not shown), and in particular by the same lid that also closes the upper surface of the space for cooling goods  300 . 
     The coolant may be water. However, the present disclosure is not limited to the use of water, and any other coolant suitable for the present purpose or any suitable cooling liquid can be used. 
     The coolant reservoir  400  comprises external walls  412  that are formed wavy or corrugated in a direction substantially perpendicular to the height extension of the space for cooling goods  300 , as is illustrated in the example of  FIG. 2 . In this way, the cooling device  100 , and in particular the coolant reservoir  400  can be provided with an increased stability. 
     The cooling device  100  comprises a cooling space  110  having four cooling space sidewalls  112 , a cooling space base  114 , and a closable lid (not shown) designed to close the space for cooling goods  300  at its upper surface. The space for cooling goods  300  and the coolant reservoir  400  are disposed in the cooling space  110  or inserted into the cooling space  110 . Typically, the upper surface of the space for cooling goods  300  and the upwardly open coolant reservoir  400  can be closed by the same lid. In this way, the cooling device  100  can have a simple construction. 
     Between the four cooling space sidewalls  112  of the cooling space  110  and the external walls  312  of the space for cooling goods  300  there is formed a receiving space  120  or cavity. The coolant reservoir  400  is disposed in said receiving space  120 . The receiving space  120  is at least partially filled with air, as shown in  FIG. 2 , and/or an insulation material (not shown), for example an insulating foam. The insulation material thermally insulates the space for cooling goods  300  from the environment of the cooling device  100  or outside world, respectively. 
     Typically, the coolant reservoir  400  is spaced from the four cooling space sidewalls  112  of the cooling space  110  and/or the external walls  312  of the space for cooling goods  300 . By providing a distance between the space for cooling goods  300  and the coolant reservoir  400  a predetermined thermal insulation between the space for cooling goods  300  and the coolant reservoir  400  is achieved. Here, the distance is selected such that a predetermined heat exchange between the space for cooling goods  300  and the coolant reservoir  400  occurs. In this way, it is prevented that the interior of the space for cooling goods  300  falls to a temperature below 2° C. The region between the space for cooling goods  300  and the coolant reservoir  400  can at least partially be filled with the insulation material, for example the insulating foam. 
     The cooling space  110 , the coolant reservoir  400 , and/or the space for cooling goods  300  preferably consist(s) of a plastic, for example of polyethylene or polypropylene. Of course, the respective parts may also consist of another suitable material, in particular metal. The cooling space  110 , the coolant reservoir  400 , and the space for cooling goods  300  in the present example are integrally formed. However, the cooling space  110 , the coolant reservoir  400 , and the space for cooling goods  300  may also have a multi-part design. 
     The cooling device  100  in the space for cooling goods  300  allows to provide a temperature in a particular range of for example +2 to +8° C., for example if the electric primary cooling circuit of the cooling device  100  is not functional due to a power interruption, for example at night or in case of a cloudy sky or power failure. This is done by a suitable design of the coolant circuit, the volume of the coolant reservoir  400 , the height of the coolant reservoir  400 , the type and amount of the insulation material in the receiving space  120 , the distance between the space for cooling goods  300  and the coolant reservoir  400 , and/or a combination of said measures. Optionally, further a heating device (not shown) can be provided that is designed to supply heat to the space for cooling goods  300 . In this way, for example it can be prevented that the interior of the space for cooling goods  300  falls to a temperature below 2° C. For example, such a heating device can be battery-powered, so that the heating device also functions in case of a lacking external energy source. 
       FIG. 3  shows a schematic illustration of the cooling circuit of the cooling device  100 .  FIG. 4  shows a schematic sectional view of the cooling device  100  having the evaporator  220  with loops in accordance with embodiments of the present disclosure. 
     The evaporator  220  is formed as a tubular evaporator and extends at least partially in a circumferential direction of the space for cooling goods  300 , so that the evaporator at least partially surrounds the upper region of the space for cooling goods  300 , and in particular an upper circumferential region of the space for cooling goods  300 . 
     Here, the evaporator  220  comprises at least one loop, and in accordance with the described example three loops. In this way, the at least one evaporator  220  can be disposed in the coolant reservoir  400  in a simple manner and with little effort, so that the evaporator  220  is looped around the upper region of the space for cooling goods  300 . By the loop-shaped tubular evaporator the coolant can uniformly be cooled and frozen in the coolant reservoir  400 . 
     As is shown in the example of  FIGS. 3 and 4 , the evaporator  220  has a tube  222  that starting from the compressor  210  at least partially extends around a circumferential region of the space for cooling goods  300  and then, following a first (perpendicular) bend  224  by about 180° goes back towards the compressor  210 . Said path forms a first loop. The evaporator  220  has a second (perpendicular) bend  226  by about 180° and thus, forms a second loop etc. In the described example the evaporator  230  has three loops, as shown in  FIGS. 3 and 4 . However, an evaporator having less or more loops is also conceivable. 
     Moreover, in  FIG. 5  and  FIG. 6  an alternative embodiment of an evaporator  220  is illustrated. The evaporator  220  has a tube  222  that starting from the (not illustrated) compressor  210  extends around a circumferential region of the space for cooling goods  300 . Here, the tube extends with a slight inclination of about 5° to 15°. 
     Irrespective of the actual design of the evaporator  220  the coolant reservoir  400  completely surrounds the upper region of the space for cooling goods  300 , and in particular the upper circumferential region of the space for cooling goods  300 . In this way, the space for cooling goods  300  is cooled uniformly and from all sides, so that the temperature distribution within the space for cooling goods  300  is homogenous. This is of particular advantage for storing medical products, since the stored articles, for example the vaccine or blood products, are substantially exposed to the same temperature. 
     The upper region of the space for cooling goods  300  that is at least partially or completely surrounded by the coolant reservoir  400  corresponds to 10% to 90% of the height of the space for cooling goods  300 , and in particular 40% to 60% of the height of the space for cooling goods  300 . Therefore, on the one hand sufficient cooling of the space for cooling goods  300  is ensured, and on the other hand the weight of the cooling device  100  is reduced, since the space for cooling goods  300  is not completely, i.e. over its total height, surrounded by the coolant reservoir  400  or embedded or immersed into it. 
     In the example the cooling device  100  is formed as a freezer for storing and transport of medical products, for example vaccines or blood products. Such freezers may advantageously be employed in remote areas, for examples in developing countries, where a stable and safe continuous energy supply, for example via a power supply system, cannot be ensured. 
     The present invention provides a cooling device in which at least one evaporator is directly disposed in a coolant reservoir or in the coolant, respectively. By disposing the evaporator of the cooling circuit in the coolant reservoir, i.e. in the coolant, for example water, a good energy flow between the coolant and the evaporator can be ensured which allows a rapid freezing of the coolant, for example in less than 1 hour at reduced energy expenditure. Moreover, by providing the coolant reservoir no additional cooling space for freezing or storing ice bags or freeze packs is needed, whereby the cooling device can be formed compact and simple. Moreover, production costs can be reduced, since no such separate ice bags or freeze packs are needed and the cooling device can be produced in a simple and inexpensive manner.