WO2008000946A2

WO2008000946A2 - Method for conserving food products stored in an enclosure

Info

Publication number: WO2008000946A2
Application number: PCT/FR2007/001060
Authority: WO
Inventors: Cédric WAROUX; Constantin Nicolaou; Philippe Jacquemin; Paul Rivier
Original assignee: Eurocave Sa
Priority date: 2006-06-27
Filing date: 2007-06-26
Publication date: 2008-01-03
Also published as: FR2902867A1; CN101479548B; FR2902867B1; EP2032920A2; WO2008000946A3; CN101479548A

Abstract

According to this method, the parameters of the air-conditioning device are predetermined and/or its operating conditions are regulated in such a way that no point of the internal atmosphere of the enclosure, and no point in contact with this internal atmosphere, is at a temperature of less than 0°C.

Description

METHOD FOR PRESERVING FOOD PRODUCTS STORED IN AN ENCLOSURE

The present invention relates to a method for preserving food products stored in an enclosure.

The foodstuffs targeted by the invention are more particularly, but not exclusively, foods requiring a relatively average storage and storage temperature, for example between 5 and 20 ^° C. In this category, there are in particular solid products or the most naturally tasty liquids, such as cheese, wine, vegetables, fruits or cured meats.

Within the meaning of the invention, the storage chamber, intended for the preservation of the aforementioned foodstuffs, may have various sizes, for example between a few liters and a few cubic meters. The invention is more particularly autonomous enclosures, susceptible for this purpose to be transported from one place to another, but it also finds its application to parts of a home, such as a storeroom.

In known manner, the food products stored in a chamber are kept by implementing an air conditioning device, to maintain a controlled temperature inside the enclosure. Conventionally, such a device comprises a compressor, from which extends a cold loop conveying a refrigerant. This first passes through a condensing stage, at high pressure, then is subjected to a relaxation, for example in a tube called capillary, before flowing into an evaporation stage where it gives cold to the air. enclosure to be treated.

The solutions implemented in the state of the art are not satisfactory, especially insofar as they induce significant drying of the atmosphere of the enclosure. This is accompanied by negative consequences in terms of appearance, dryness and taste of food stored in this chamber.

That being said, the invention aims to remedy these various disadvantages. For this purpose, it relates to a method of preserving foodstuffs stored in an enclosure, by means of an air conditioning device, in which the parameters of said device are predetermined and / or the operating conditions of said device are regulated, such so that no point of the interior atmosphere of the enclosure, and no point in contact with this interior atmosphere, is at a negative temperature, namely less than 0 ^° C.

According to other features of the invention:

the air conditioning device comprises a compressor, a condensing member, an intermediate expansion member and an evaporation member, the parameters of this device comprising the maximum power of the compressor, as well as the dimensions of the expansion and the evaporation member, while the operating conditions include the instantaneous power of the compressor, as well as the temperature and the pressure of the fluid flowing in the evaporation member;

the fluid is circulated at a temperature of between -3 ^° C. and + 4 ° C. in the evaporation member;

the fluid is circulated at a pressure of between 2.5 and 3.5 bars in the evaporation member; per cubic meter of enclosure, an evaporation member length of between 40 and 60 meters is used, for a section of this element between 4 and 8 mm;

the compressor is actuated in a substantially continuous manner at a power corresponding to a small fraction of its maximum power; a cooling fluid based on water is circulated in the evaporation member;

- The refrigerant is circulated in an evaporation member having a first open end, placed in the chamber, it is trickled fluid inside this chamber, it collects this fluid in a tray and recovers all or part of this fluid by a second open end of the evaporation member.

The invention will be described below, with reference to the accompanying drawings, given solely by way of non-limiting examples, in which: - Figure 1 is a perspective view, illustrating a food storage chamber, which can be preserved by the method of the invention; and

- Figure 2 is a schematic view, illustrating an alternative embodiment of the method of the invention.

The storage chamber illustrated in FIG. 1 is in the form of a parallelepiped block 2, of which the upper face, 2 ₂ the lower face, 2 ₃ the front face, 2 ₄ the rear face and 2 the two side faces. Conventionally, the front face ₂₃ is provided with a door, not shown in this FIG.

This enclosure ensures the storage and preservation of food products, via an air conditioning device which will be described in the following. This device comprises first of all a compressor 4 of known type, from which extends a condensation coil 6 on the rear face ₂₄ of the enclosure.

This coil 6 is extended into an intermediate flashing capillary 8, then a bypass 10, from which extend two evaporation coils 12 provided on the two opposite lateral faces ₂₅ . The coils 12 are embedded, in a manner known per se, in a layer of foam not shown in the figures, for the sake of clarity.

The downstream ends of the evaporation coils 12 are finally placed in communication with return lines, which open at the inlet of the compressor 4. It will be noted that, in FIG. 1, the condensation coil is illustrated in an exploded manner so as to better view the coils 12 extending on the face 2 ₅ shown on the left of this figure.

According to the invention, the parameters and / or the operating conditions of this air conditioning device are determined so that no point of the interior atmosphere of the enclosure, nor any point in contact with this interior atmosphere, is found. at a negative temperature. In this case, the points likely to be in contact with this interior atmosphere include the walls of the enclosure which border this interior volume.

The parameters of the air conditioning device, as defined above, include in particular the dimensions of the capillary 8 and coils 12 and the maximum power of the compressor 4. The operating conditions, as defined above, comprise in particular the temperature and the evaporation pressure of the fluid, namely those which this fluid possesses in the coils of evaporation 12 downstream of the expansion capillary 8, as well as the power supplied by the compressor 4.

According to the invention, it is possible for example to size the capillary 8, so that it provides a less significant relaxation than in conventional installations. For this purpose, it can reduce its length and / or increase its diameter, so that it provides relaxation less intense. As a purely indicative, for an enclosure whose volume is 0.5 m ³ , the devices of the prior art use a capillary whose length is 4 meters, and the diameter is 0.8 mm. For comparison, for an enclosure of the same volume, use, for example, according to the invention, a capillary 8 whose length is only 3 meters, and whose diameter is increased to 1 mm.

Under these conditions, the capillary of the prior art typically allows a relaxation from a value of 15 bar to a value close to 1 bar. In contrast, according to the invention, the expansion imparted by the capillary 8 carries the refrigerant from a value of 15 bars, which is therefore close to that of the prior art, up to a value of 3 bars, which is consequently greater than to that provided in the prior art.

Under these conditions, since the pressure of the fluid at the outlet of the capillary 8 and, consequently, in the evaporation coils 12 is greater than that prevailing in the prior art, it is possible to implement the compressor 4 to a lower power than that of the prior art. In particular, this compressor is capable of operating at variable power.

Thus, in normal operation, the compressor is used substantially continuously, at a relatively small fraction of its maximum power. Moreover, in the case of exceptional situations, such as high point temperatures, it is then possible to use it at a higher power. This is advantageous because it provides quieter operation and substantial energy savings, reach 30% compared to conventional solutions, for the same volume of enclosure.

Since, as seen above, the refrigerant is admitted into the evaporation coils 12 at a pressure higher than that of the state of the art, its temperature in the evaporation stage is also superior to that of known solutions. Thus, by way of a comparative example, the temperature of the fluid in the evaporation stage typically used in the prior art is -25 ^° C. In contrast, according to the invention, for the same refrigerant and a same enclosure volume, the temperature of this fluid in the evaporation coils 12 is brought to about 0 ⁰ C.

In addition, this increase in the evaporation temperature of the refrigerant is advantageously accompanied by an increase in the length of the evaporation stage, for the same volume to be treated. For this purpose, it is recalled that, at least on first approach, the value of the heat exchange between the refrigerant and the inside of the enclosure is a function of the product, on the one hand, of the temperature difference between this fluid and this enclosure and, on the other hand, the length of the evaporation coil. However, this difference in temperature is lower than in the prior art, in accordance with the invention, so that an increase in the length of the coil makes it possible to obtain an overall value of heat exchange corresponding to that of the state of the art.

As a purely indicative example, in the prior art, for a volume to be treated of 0.5 m ³ , an evaporation coil is used, the length of which is 9 meters, for a diameter of 6 mm. According to the invention, for the same volume of enclosure and the same section of evaporation coil, the latter has a length close to 24 meters, namely more than two and a half times greater than the coil of the prior art. In this respect, it will be noted that the two opposite lateral faces ₂₅ of the enclosure are covered with such an evaporation coil 12, which makes it possible to produce this larger exchange surface.

The invention achieves the previously mentioned objectives. Thus, it provides to use a refrigerant flowing in the evaporation stage at a temperature significantly higher than that prevailing in previous solutions. Therefore, this ensures that no point, either of the indoor atmosphere or in contact with this indoor atmosphere, is at a temperature below 0 ⁰ C.

Under these conditions, the drying phenomena of this atmosphere, related to a cold supply at negative temperatures in the state of the art, are substantially eliminated thanks to the invention. This suppression is therefore accompanied, in accordance with the invention, by an improvement of the various characteristics of the food products stored in the enclosure, in particular in terms of appearance, hygrometry and taste.

Since the evaporation temperature of the fluid is higher than in the prior art, according to the invention, it is possible to circulate cold water around the enclosure. This water is then cooled, away from this chamber, by means of a conventional refrigerant capable of operating at the usual low temperatures.

This embodiment is advantageous since it makes it possible to reduce the volume of conventional refrigeration fluid used. It also allows greater ease of maintenance of the apparatus, since the conventional refrigerant is dissociated from the enclosure itself.

According to another embodiment of the invention, the evaporation coils can be installed inside the enclosure. Indeed, since the evaporation temperature provided by the invention is relatively high, a circulation of such a fluid is not likely to induce a gel inside the chamber. Moreover, given the temperatures used, there is no risk of burning for a user, if the latter comes into contact with the coil. This embodiment is advantageous in terms of efficiency. Indeed, since the evaporation coil extends inside the chamber, it allows a direct heat exchange with the indoor atmosphere of this chamber.

According to another variant not shown, the or each evaporation coil can be replaced by a radiator, of known type, placed inside the enclosure. This embodiment is advantageous in economic terms, since it induces only a low cost of implementation. FIG. 2 illustrates a further variant embodiment on which the walls of the enclosure are represented in phantom. In this variant, a coil 112 is used which penetrates inside the enclosure, while having a first open end 112 '. The latter extends in the vicinity of an inclined wall 114, also internal to the enclosure, below which is provided a recovery tank 116. The other end 112 "of the coil, also open, plunges into the tray 116 while being in communication with the compressor, not shown in this figure.

In use, the coolant, which is in particular water, is discharged by the end 112 ', then flows along the wall 114 until it is collected in the tank 116. By a pumping system, this water is recovered at the end 112 ", then returned to the main circuit.

The embodiment of this FIG. 2 is advantageous since it contributes to an automatic supply of moisture inside the enclosure. This is particularly favorable for leafy vegetables. In order to compensate for any evaporation of the water used, it is possible to provide a supplementary water supply, preferably via a connection to the main network.

It will be noted that, in the foregoing, the variant of FIG. 2 contributes to providing, not only the necessary humidity, but also the desired temperature value. Alternatively, it can be provided that the embodiment described in this Figure 2 contributes only to ensure a moisture supply, the addition of frigories being further provided by means of a closed loop as described above.

As a further variant, not shown, it can be provided to bring into the chamber, or to extract from it, appropriate gases. This may allow, in a manner known per se, to promote the preservation or ripening of foods, depending on their nature.

Claims

1. A method for storing food products stored in an enclosure (2), by means of an air conditioning device, in which the parameters of said device are predetermined and / or the operating conditions of said device are regulated, so that no point of the interior atmosphere of the enclosure, and no point in contact with this indoor atmosphere, is at a negative temperature, namely less than 0 ⁰ C.

2. Method according to claim 1, characterized in that the air conditioning device comprises a compressor (4), a condensing member (6), an intermediate expansion member (8), and an evaporation member (12). ; 112), the parameters of this device comprising the. maximum power of the compressor (4), as well as the dimensions of the expansion member (8) and the evaporation member (12; 112), while the operating conditions include the instantaneous power of the compressor (4), and the temperature and pressure of the fluid flowing in the evaporation member (12; 112).

3. Method according to claim 2, characterized in that circulates the fluid at a temperature between -3 ° C and + 4 ° C, in the evaporation member (12; 112).

4. Method according to claim 2 or 3, characterized in that circulates the fluid at a pressure between 2.5 and 3.5 bar in the evaporation member (12; 112).

5. Method according to one of claims 2 to 4, characterized in that, per cubic meter of enclosure, is used a length of evaporation member between 40 and 60 meters, for a section of this body between 4 and 8 mm.

6. Method according to one of claims 2 to 5, characterized in that actuates, substantially continuously, the compressor (4) at a power corresponding to a small fraction of its maximum power.

7. Method according to one of claims 2 to 6, characterized in that circulates a water-based refrigerant in the evaporation member (12).

8. Method according to one of claims 2 to 7, characterized in that circulates the refrigerant in an evaporation member (112) having a first open end (112 '), placed in the chamber, on flowing this fluid inside this chamber, this fluid is collected in a tank (116) and all or part of this fluid is recovered by a second open end (112 ") of the evaporation member (112) .