WO2012062314A1

WO2012062314A1 - Refrigerator with a temperature buffer

Info

Publication number: WO2012062314A1
Application number: PCT/DK2010/000144
Authority: WO
Inventors: Lars Goruelak
Original assignee: A/S Vestfrost
Priority date: 2010-11-08
Filing date: 2010-11-08
Publication date: 2012-05-18
Also published as: WO2012062314A8

Abstract

Disclosed herein is a refrigerator for storing elements, e.g. medicine, said refrigerator comprises 1 ) an inner wall defining a compartment for storing said elements; 2) an outer wall; 3) insulation material positioned between said inner wall and said outer wall; 4) evaporation means positioned between said inner wall and said insulation material; and 5) at least one freezing element positioned between said inner wall and said evaporation means.

Description

Refrigerator with a temperature buffer

The invention relates to a refrigerator for storing e.g. medicine, such as vaccines, or food and beverages, the refrigerator comprises at least one freezing element which ensures that the temperature of the product stored inside it is maintained over a long period of time with no supply of electricity to the refrigerator.

Background

A good quality refrigerator for storing e.g. medicine such as vaccines needs to comprise a temperature buffer, which ensures that the inner temperature of the refrigerator is maintained in the case of a power breakdown for a long period of time. Similarly, this feature is advantageous to have employed in other types of refrigerators and freezers. A known way of ensuring this is to add frozen elements to the inside of the refrigerator. When the power breaks down, the heat from the content of the refrigerator is transferred to the frozen liquid, thereby maintaining the inner temperature. In known solutions found e.g. in GB1338553, freezing elements are added to the inside of the refrigerator as separate units positioned parallel to the inner wall and then optionally a frame is added to fixate the elements against the inner wall of the refrigerator. A problem with this solution is, however, that dirt and bacteria can easily accumulate in the cracks obtained because of the freezing elements positioned at the inside of the refrigerator. Further, the space in the refrigerator is significantly decreased because of the freezing elements. Also, the freezing elements might not be completely frozen due to the placement of them relatively far away from the source of cooling. Description of the invention

Disclosed herein is a refrigerator for storing elements e.g. medicine, such as vaccines, or food and beverages, said refrigerator comprises 1 ) an inner wall defining a compartment for storing said elements; 2) an outer wall; 3) insula- tion material positioned between said inner wall and said outer wall; 4) evaporation means positioned between said inner wall and said insulation material; and 5) at least one freezing element positioned in between said inner wall and said insulation material. Thereby is obtained a refrigerator which ensures that the temperature of the elements stored therein is maintained over a long period of time with no supply of electricity to the refrigerator. The refrigerator has an advantageously smooth inner surface, which is easy to clean. Consequently, the risk of dirt and bacteria accumulating in and around the freezing elements are at an ab- solute minimum as these are positioned behind the inner wall. Further, by the positioning of the evaporation means behind the freezing element, the thermal energy is accumulated more efficiently in the freezing elements, whereby it is ensured that the freezing elements will be completely frozen due to the close proximity to the evaporation means at the same time as the energy consumption of the refrigerator is reduced. Additionally, the space inside the refrigerator is not affected by the placement of the freezing elements.

In one or more embodiments said refrigerator further comprises a fixation profile for supporting said at least one freezing element, wherein said fixation profile is positioned between said at least one freezing element and said evaporation means. Thereby a firmer fixation of the freezing elements is obtained.

In one or more embodiments said evaporation means are multiple evapora- tion tubes. In one or more embodiments said refrigerator comprises multiple freezing elements, thereby more efficiently keeping the temperature of the products inside the refrigerators at a constant temperature for a long time without power supply.

In one or more embodiments said multiple freezing elements have a rectangular shape making it easy to place them next to one another in a row.

In one or more embodiments said multiple freezing elements are positioned along side one another in a line surrounding said compartment for storing said elements. Thereby the temperature of the products inside the refrigerators is efficiently kept at a constant temperature for a long time without power supply. In one or more embodiments said refrigerator is operating as a freezer at temperatures below 0 °C.

In one or more embodiments said refrigerator is operating as a low temperature freezer at temperatures below -40 °C.

Brief description of the drawings

Figures 1a-c illustrate a refrigerator according to the invention.

Description of preferred embodiments

Figure 1a illustrates a refrigerator 100 according to the invention in a cross section viewed from the front, and figure 1b shows the close up marked with the circle in figure 1a. The refrigerator 100 has a compartment 102 for storing products and is opened by a lid at the top 106. The refrigerator 100 shown in the figures is in the shape of a chest freezer. However, other designs such as e.g. an upright refrigerator with a door opening outwards in the room instead of a lid at the top could equally well be imagined. The refrigerator 100 can be used e.g. for storing medicine, such as vaccines, or for storing food and beverages, in the latter two cases e.g. operating as a regular household refrigerator or household freezer at a temperature of approximately 5 °C and -18 °C, respectively. The refrigerator 100 can also be used as a low temperature freezer operating at temperatures from -40 °C and down below -100 °C.

The refrigerator 100 further comprises a compartment 108 for storing electronics, a compressor, a thermostat and related objects, such as e.g. a venti- lator.

Also the refrigerator 100 comprises freezing elements 110, which are situated in between the inner wall 112 and the outer wall 114 of the refrigerator 100. The freezing elements 110 are surrounded by insulation material 116, e.g. polyurethane (PUR) foam. In figure 1a, two freezing elements 110 are seen, however it should be understood that multiple freezing elements 110 can surround the entire circumference of the refrigerator compartment 102 in the horizontal plane, possibly in multiple layers vertically. If the refrigerator 100 is in another shape such as e.g. an upright refrigerator, the freezing ele- ments 110 will surround the circumference of the refrigerator compartment 102 in the upright plane.

The freezing elements 110 are normally in the shape of rectangular boxes made of plastic, but other shapes such as tubes and other materials could be imagined depending on the requirements to the operating temperature of the refrigerator 100. A multiple of smaller freezing elements 110 are used in the embodiment shown in the figures, however, one long continued freezing element could also be imagined, either extending the entire way around the circumference of the refrigerator 100 or only part of the way. Along side the freezing elements 110, evaporations tubes 118 are arranged as also shown in the side view in figure 1c. The evaporation tubes 118 contain a cooling agent, which ensures that the refrigerator compartment 102 is cooled to a desired temperature. The evaporation tubes 118 are one way of cooling the refrigerator and other evaporation means such as e.g. evaporation plates or electrical Pieltier modules could equally well be imagined.

The freezing elements 110 contain a freezing liquid, which are cooled down/frozen by the evaporation tubes 118. The freezing liquid has a phase shift temperature matching the temperature requirements of the refrigerator, which is defined by the product to be stored inside it. When using the refrigerator for cooling vaccines, water is a good freezing liquid as it has a phase shift at 0 °C. If the operating temperature of the refrigerator needs to be lower, e.g. around -18 °C as found in a regular household freezer or between -40 °C and -100 °C or even lower as found in low temperature boxes, other phase change materials (PCM) is often used as the freezing liquid. This could e.g. be a eutectic PCM solution.

The evaporation tubes 118 are arranged on the back side of the freezing elements 110 (see figure 1c), whereby the evaporator tubes 118 efficiently freeze the freezing elements 110 before cooling the refrigerator compartment 102. This is a very efficient way of cooling both the freezing elements 110 and the refrigerator compartment 102 using less energy compared to e.g. a placement of the evaporation tubes 102 in between the freezing ele- ments 110 or a placement of the freezing elements 110 inside the refrigerator compartment 102. Further, it is ensured that the freezing elements will be completely frozen due to the close proximity to the evaporation tubes 118.

By placing the freezing elements 110 behind the inner wall 112, accumulation of dirt and bacteria in cracks around the freezing elements 110 (as observed in prior art solutions where the elements are placed inside the refrigerator compartment) cannot occur. Further, the space inside the refrigerator compartment 102 is maintained when the freezing elements 110 are inserted.

In case of a power break down or low energy supply, the freezing elements 10 serve as a temperature maintaining buffer; thermal energy from the refrigerator compartment 102 is transferred to the frozen liquid in the freezing elements 110, whereby the inner temperature of the refrigerator 100 is maintained for a given time period. When using the refrigerator 100 for storing vaccines, the temperature buffer can maintain the temperature over a long period of time in appliance with the international standards. However, the principle with a thermal buffer and the positioning of freezing elements behind the inner wall can also be applied in other types of refrigerators and/or freezers. Depending on the requirements to the temperature and the time period for which the freezing elements need to maintain the temperature in- side the refrigerator, the size of the freezing elements, the number of them and the freezing liquid inside can vary.

The freezing elements 110 can be kept in position by the insulation material 116, or optionally a fixation profile 120 can be added to further support the freezing elements 110. The fixation profile 120 shown in the figures extends around three sides of the freezing elements 110, but could alternatively only support the freezing elements 110 at one or two sides of the sides. Normally the fixation profile 120 is added such that it lies in between the freezing elements 110 and the evaporation tubes 118, but it could also be positioned be- hind the evaporations tubes 118. References

100 refrigerator

102 compartment

106 lid

108 compartment for the electronics

110 freezing element

112 inner wall of the refrigerator

114 outer wall of the refrigerator

116 insulation material

118 evaporation tubes

120 fixation profile

Claims

1. A refrigerator for storing elements, e.g. medicine, such as vaccines, or food and beverages, said refrigerator comprising:

- an inner wall defining a compartment for storing said elements; - an outer wall;

- insulation material positioned between said inner wall and said outer wall;

- evaporation means positioned between said inner wall and said insulation material; and

- at least one freezing element positioned between said inner wall and said evaporation means.

2. A refrigerator according to claim 1 , wherein said refrigerator further comprises a fixation profile for supporting said at least one freezing element, wherein said fixation profile is positioned between said at least one freezing element and said evaporation means.

3. A refrigerator according to claim 1 or 2, wherein said evaporation means are multiple evaporation tubes.

4. A refrigerator according to any one of the claims 1-3, wherein said refrigerator comprises multiple freezing elements.

5. A refrigerator according to any one of the claims 1-4, wherein said multi- pie freezing elements have a rectangular shape.

6. A refrigerator according to claim 4 or 5, wherein said multiple freezing elements are positioned along side one another in a line surrounding said compartment for storing said elements.

7. A refrigerator according to any one of the claims 1-6, wherein said refrigerator is operating at a temperature above 0 °C.

8. A refrigerator according to any one of the claims 1-6, wherein said refrig- erator is operating as a freezer at temperatures below 0 °C.

9. A refrigerator according to any one of the claims 1-6, wherein said refrigerator is operating as a low temperature freezer at temperatures below -40 °C.