NO347065B1

NO347065B1 - Device and method for dehumidifying a cold storage

Info

Publication number: NO347065B1
Application number: NO20221169A
Authority: NO
Inventors: Gunnvald Harila; Fredrik Oledal
Original assignee: Friofox As
Priority date: 2022-10-31
Filing date: 2022-10-31
Publication date: 2023-05-02
Also published as: NO20221169A1

Description

Device and method for dehumidifying a cold storage

Technical Field

[0001] The present invention is concerned with dehumidifying of cold storages.

Specifically, the invention is concerned with a novel device and method for dehumidifying a cold storage and a cold storage comprising such a device.

Background

[0002] Cold storages are commonly utilized for the temporary storage of perishable products, such as perishable foods, beverages, medicines, biological matter, food waste, or temperature sensitive chemicals. Venues such as restaurants, supermarkets, storage facilities, or distribution centers all rely on cold storages to maintain a stock of perishable products. Such cold storages normally comprise a space, such as a cabinet, a room or a hall, of appropriate size, which is kept at a predetermined temperature. Preferably, the cold storage is at least partly insulated, to prevent leaking of heat from outside into the cold storage. Depending on the type of products stored, the cold storage may be maintained at a desired operating temperature. Such operating temperatures may range from above zero degrees Celsius, down to tens of degrees below zero degrees Celsius. In order to prevent the spoiling of perishable products, the uninterrupted and fail-free functioning of a cold storage is imperative.

[0003] In order to move products from and to a cold storage, personnel must have access thereto. During each entry into, or exit from, the cold storage, warmer outside air may enter the cold storage. When entering the cold storage, the warmer outside air is cooled to the ambient temperature within the cold storage. In most cases however, the warmer outside air comprises humidity, which condenses within the cold storage during cooling. The condensed humidity then accumulates within the cold storage and, depending on the temperature therein, may raise the humidity levels within the cold storage or freeze into ice deposits on surfaces within the cold storage. Either effect is detrimental to the storage of perishable products. Raised humidity levels may contribute to the growing of undesirable fungi or molding within the cold storage, potentially leading to product spoilage and unhealthy working conditions. The depositing of ice, on the other hand, may necessitate de-icing operations, aiming to remove ice from the cold storage and from the products stored therein. Notably, such de-icing may be necessary frequently, such as weekly or monthly, during which all stored products must temporarily be moved or stored elsewhere. Such de-icing operations are therefore both labor- and cost-intensive. In addition, ice deposits may form on the cold storage cooling circuit equipment, such as the evaporator. De-icing of the evaporator may therefore be necessary at regular, daily or even hourly, intervals.

[0004] From DK 171122 B1, an arrangement for collection and removal of moisture in a cold storage is known, where an inlet is arranged through the cold storage’s insulating wall. The inlet is connected to a dehumidifier on the outside of the cold room. The arrangement has no outlet from the cold room.

[0005] Furthermore, a cold storage may require a pressure equalization valve. This is especially the case for cold storages maintained at low temperatures as compared to the environment directly outside the cold storage, such as for cold storages operated at temperatures well below 0ºC. A pressure equalization valve ensures that the pressure within the cold storage roughly equals the pressure outside the cold storage. Thereby, it remains possible to open the cold storage entry door and furthermore the strain on the cold storage walls due to pressure differences does not become so large as to cause structural damage. A pressure equalization valve forms an additional component to be installed in the cold storage, complicating cold storage construction and thereby increasing expenses.

[0006] Consequently, there is a clear need for maintaining low humidity levels within cold storages, without hampering the necessary access to the products within the cold storage. Additionally, it is desirable to simultaneously reduce the need for a pressure equalization valve. Finally, the solution should be easy to incorporate in both existing and new cold storages.

Summary of the invention

[0007] The present invention concerns device for dehumidifying a cold storage according to claim 1. The present invention also concerns a cold storage according to claim 8. Finally, the present invention also concerns a method for dehumidifying a cold storage according to claim 11.

Figures

[0008] Figure 1A schematically shows a sideview of a device according to the invention.

[0009] Figure 1B schematically shows a top view of a device according to the invention.

[0010] Figure 2A schematically shows cross-section of a pipe segment of a device according to the invention.

[0011] Figure 2B schematically shows flow around a cross-section according to fig.

2A.

[0012] Figure 3 schematically shows a detail of an inlet of a device according to the invention.

[0013] Figure 4 schematically shows a further embodiment of the present invention, comprising a first pipe segment with an inlet portion and an extending portion.

[0014] Figure 5 schematically shows a further embodiment of the present invention, comprising a coupling between a first pipe segment and the second pipe segment.

Detailed description

[0015] Fig.1A and 1B schematically show a device for dehumidifying a cold storage 1, according to the invention. The same references appearing in fig.1A and in all other figures denote the same features. Fig.1A schematically shows a sideview, including the ceiling 1a and part of the sidewalls 1b of a cold storage 1. Fig.1B schematically shows a top view, corresponding to fig.1A. The cold storage 1 comprises a storage space provided with at least one entry (not shown), through which products and / or personnel can enter or leave the storage space. Exemplary cold storage spaces 1 include cold storage cabinets, such as a food or beverage vending machine, a fridge, a freezer, or a refrigerated counter, cold storage containers, cold storage transport vehicles, such as a cold storage transport truck, cold storage rooms, such as refrigerated storage rooms in restaurants, or cold storage halls, such as a refrigerated warehouse or refrigerated distribution center. The cold storage 1 may be maintained at a given operating temperature or within a given operating temperature range. Operating temperatures may range from just below room temperature, such as up to 10°C, up to 15°C, or even up to 20°C, to many degrees below 0°C, such as down to -20°C, down to -50°C, or even down to -100°C. Exemplary temperature ranges are, for instance, 10 to 20°C for wine coolers, 0 to 5°C for refrigerated counters, -15 to - 20°C for deep freeze food storages, or -50 to -100°C for certain vaccine storages. Naturally, the cold storage 1 is maintained is configured to be maintained at an operating temperature corresponding to the type of perishable goods stored therein.

[0016] With reference to fig.1A, the device includes at least a first pipe segment 2a and a second pipe segment 2b. The first pipe segment 2a is connected to the second pipe segment 2a. Preferably, the first pipe segment 2a is connected to the second pipe segment 2b in a fluid tight manner. Further pipe segments (not shown), may be arranged between the first pipe segment 2a and the second pipe segment 2b. Any further pipe segment is preferably connected to the first pipe segment 2a and the second pipe segment 2b in a fluid tight manner. A sealing may be arranged between the first pipe segment 2a, the second pipe segment 2b and / or any further pipe segments. Alternatively, the first pipe segment 2a, the second pipe segment 2b and / or any further pipe segments may be formed as a single pipe.

[0017] A cross section of the second pipe segment 2b is schematically shown in fig. 2. Each pipe segment may preferably have a T-shaped cross section, comprising two side wings 2b’ and a lower end 2b’’ (further detailed below). Alternatively, each pipe segment may have an inverse L-shaped cross section, with a single side wing. Further alternatively, the pipe segments may have circular cross-section, a rectangular cross-section, an oval cross-section, a triangular cross-section, or any other suitable cross-section. Each pipe segment may comprise a metal, such as copper or aluminum. Alternatively, each pipe segment may comprise a polymer material, such as polyvinyl chloride (PVC), or acrylonitrile butadiene styrene (ABS). Further alternatively, each pipe segment may comprise a composite material, such as a glass fiber reinforced polymer material, or a layered metal-polymer composite material. The pipe segments may be formed by extrusion, by drawing, by welding, or by any other suitable production method.

[0018] The first pipe segment 2a includes an inlet 3 for the inflow of air into the device. The inlet is preferably arranged for the intake of air from outside the cold storage 1. At least a portion of the first pipe segment 2a is arranged to extend upwards from the inlet 3. The portion of the first pipe segment 2a extends upwards at an angle α with respect to the horizontal direction. The angle α is within the range 0 < α ≤ 90°, preferably within the range 30 ≤ α ≤ 60°. Advantageously, any liquid collected in the first pipe segment 2a may thereby flow towards the inlet 3 and exit the device therethrough. The portion of the first pipe segment 2a extending upwards from the inlet 3 is arranged within the cold storage 1.

[0019] With further reference to fig.1A, the second pipe segment 2b includes an outlet 4, for the outflow of air from the device. In operation, air may flow through each pipe segment, from the inlet 3 to the outlet 4. The second pipe segment 2b may be arranged horizontally, or near-horizontally in the cold storage 1. Preferably, the second pipe segment 2b is arranged to extend parallel to the ceiling of the cold storage 1. Thereto, the second pipe segment 2b may be attached to, or suspended from the ceiling of the cold storage 1.

[0020] With reference to fig.1B and 2A, the second pipe segment 2b includes one or more apertures 5. In operation, air may flow through the apertures 5 from the cold storage 1 into the second pipe segment 2b and, inversely, from the second pipe segment 2b into the cold storage 1. Optionally, each further pipe segment may also include one or more apertures 5. The one or more apertures 5 are arranged along one side of the pipe segment. Alternatively, the one or more apertures 5 may be arranged along two or more sides of the pipe segment. Preferably, the one or more apertures 5 are placed equidistantly along the length of the pipe segment. In one example, as shown in fig.1A, 1B, 2A and 2B, the second pipe segment 2b may have a T-shaped cross-section. The one or more apertures 5 may then preferably be placed on either side of the stem part 2b’’, in the planes of the wing parts 2b’ having a normal direction parallel to the stem part 2b’’. The one or more apertures 5 on either side of the stem part 2b’’ may be offset from one another.

[0021] The device further includes a ventilator 6, for generating an airflow from the inlet 3 to the outlet 4. The ventilator 6 is arranged at the outlet 4, and configured to draw a flow of air from the inlet 3 to the outlet 4.. Preferably, the ventilator 6 is electrically driven. The power supply (not shown) may comprise a battery, or a power cord, connected to a power outlet. The ventilator 6 may preferably be insulated by an insulated housing. Advantageously, unwanted condensation on the ventilator may thereby be prevented. Unwanted condensation may arise due to the temperature difference between the cold air, exiting the cold storage 1, and the warmer ambient air outside the cold storage. Similarly, any portion of the outlet 4 protruding from the cold storage 1 may be insulated. Advantageously, unwanted condensation occurring on the outside of the outlet 4 may thereby be prevented.

[0022] As shown in fig.1A and 2A, the device preferably includes one or more insulators 7, placed between the ceiling 1a or the sidewall 1b of the cold storage 1 and the first pipe segment 2a, the second pipe segment 2b and / or any further pipe segments. The one or more insulators 7 may preferably be spaced apart from one another. The one or more insulators 7 may comprise an insulating material, such as a rubber, a polymer material, or a composite material. Advantageously, a pipe segment may thereby be insulated from the cold walls or ceiling of the cold storage, such that the air flowing in the second pipe segment 2b may retain its heat as long as possible. Furthermore, by spacing insulators 7 apart, air may flow between the second pipe segment 2b and the ceiling 1a. Thereby, circulation around the second pipe segment 2b is maintained, leading to an increased transport capacity of humidity into the one or more apertures 5. As schematically shown with grey arrows in the crosssectional view of fig.2B, flow around a T-shaped pipe segment may collide with the stem part 2b’’ and thereby be forced to flow into the apertures 5.

Advantageously, a cross section comprising a stem part and at least one wing part, such as a T-shaped, or a Γ-shaped cross section, thereby increases flow into the apertures. The device may further include one or more heating cables 8, as schematically shown in fig.2A and 2B (detailed further below).

[0023] In operation, air drawn into the device by the ventilator 6 is cooled in the portion of the first pipe segment 2a arranged within the cold storage 1. Any liquid, such as water, that condensates from the air during cooling may thereby collect within the first pipe segment 2a. Under the influence of gravity said liquid flows to the inlet 3 and exits the device. Consequently, humidity levels in the air flowing in the first pipe segment 2a are lowered. The air is thereby partially, preferably completely, dehumidified. Driven by the ventilator 6, the dehumidified air flows into the second pipe segment 2b. A pressure difference arises between the dehumidified air in the second pipe segment 2b and the air in the surrounding cold storage 1, caused by the flow speed of the dehumidified air. The pressure difference causes air from the cold storage to be drawn into the second pipe segment 2b through the one or more apertures 5. Additionally, differences in humidity levels between the dehumidified air in the second pipe segment 2b and the air in the cold storage 1 cause humidity to move from the cold storage 1 through the one or more apertures 5, into the second pipe segment 2b. Thereby the air flowing in the second pipe segment 2b is partially, preferably completely, re-humidified. Finally, the re-humidified air in the second pipe segment 2b is expelled from the outlet 4, by the ventilator 6. Advantageously, humidity levels in the cold storage 1 are thereby lowered, such that the unwanted growth of fungi or mold, or the accumulation of ice deposits, may be prevented. Consequently, the need for removing mold and / or fungus and / or the need for de-icing is significantly reduced.

[0024] Additionally, in operation, the airflow through the one or more apertures 5 may temporarily be reversed during opening of an entry door into the cold storage 1. That is, in the moment of opening, air may be sucked out from the device and into the cold storage 1, thereby allowing pressure to equalize between the cold storage 1 and the outside area beyond the entry door. As the air flowing in the second pipe segment 2b is already dehumidified, after flowing through the first pipe segment 2a, the air sucked through the one or more apertures 5 into the cold storage does not significantly raise humidity levels within the cold storage 1. Advantageously, the need for a separate pressure equalization valve in the cold storage may thereby be avoided, whereas the risk of increasing humidity levels whilst opening the entry door is reduced.

Additionally, air flowing in the second pipe segment 2b may be heated by the heating cable 8. Thereby, the air flowing in the second pipe segment may be prevented from cooling so as to maintain, or even increase, its capacity for rehumidification.

[0025] As schematically shown in fig.3, the device may further include a drain 9.

The inlet 3 may be coupled to the drain 9, for collecting liquid flowing from the inlet 3 and for allowing air to flow into the inlet 3. Preferably, the inlet 3 extends vertically, or near-vertically from the first pipe segment 2a toward the drain 9. The drain 9 includes at least one opening, for the intake of air. The inlet 3 extends into the drain 9, such that air may freely flow from the outside, into the drain 9 and from the drain 9 into the inlet 3. The drain 9 may be mounted to a side wall 1b of the cold storage 1. Preferably the drain 9 may be connected to a drainage pipe 10, or any other means for allowing liquid collected in the drain 9 to be removed. Advantageously, by providing a drain removal of condensed liquid from the device is improved. The drain 9 and / or the external drainage pipe 10 may be preferably be insulated. Advantageously, condensation on the outside of the drain 9 and / or the external drainage pipe 10 may thereby be prevented. Such condensation could occur due to temperature differences between the cold liquid originating from the cold storage and the warmer ambient air outside the cold storage.

[0026] In a further embodiment, schematically shown in fig.4, an inlet portion 2a’ of the first pipe segment 2a may extend from the inlet 3 perpendicular to the sidewall 1b. An extending portion 2a’’ of the first pipe segment 2a may be arranged in the cold storage 1 and extend upward from the inlet portion 2a’ to the second pipe segment 2b. The extending portion 2a’’ may extend at an angle α with the horizontal direction. The angle α is within the range 0 < α ≤ 90°, preferably the angle α is 90º. Advantageously, in this configuration the device takes up minimal space in the cold storage. Warm outside air flowing into inlet portion 2a’ may be cooled while flowing through the extending portion 2a’’. Advantageously, humidity comprised in the warmer outside air may thereby condensate, before the air flows into the second pipe segment 2b.

[0027] In a further embodiment, schematically shown in fig.5, the device may further include a coupling 11. The first pipe segment 2a and the second pipe segment 2b may be connected by the coupling 11. The coupling 11 is preferably sealed, to prevent leakage of liquid or vapor therefrom. The coupling 11 may be connected to an external drainage pipe 10, or any other means for allowing condensate liquid collected in the coupling 11 to be removed.

Optionally, the coupling 11 may comprise a heating element 12, to heat the dehumidified air flowing therethrough. The coupling 11 is preferably placed outside the cold storage 1. In this configuration, the first pipe segment 2a comprises an inlet portion 2a’, an extending portion 2a’’, and a returning portion 2a’’’. The returning portion 2a’’’ connects the extending portion 2a’’, placed inside the cold storage 1, with the coupling 11, placed outside the cold storage 1. In the present configuration, the inlet side of the second pipe segment 2b extends outside the cold storage 1 and is connected with the coupling 11, as shown in fig.5.

[0028] The invention also concerns a cold storage 1 including a device according to the invention, as described above. The device is preferably mounted such that the inlet is arranged outside the cold storage 1, whereas the main portion of the first pipe segment 2a is arranged inside the cold storage 1. Furthermore, the device is preferably mounted such that the second pipe segment 2b is arranged parallel to the ceiling 1a of the cold storage 1. Thereto, the second pipe segment 2b may be fixed to the ceiling 1a, or suspended from the ceiling 1a. The second pipe segment 2b is further arranged to traverse a side wall 1a of the cold storage 1, such that the outlet 4 is arranged outside the cold storage. Advantageously, retrofitting the device according to the invention in an existing cold storage 1 may be easily achieved. Installing the device according to the invention in an existing cold storage 1 includes providing two throughholes in one or two sidewalls 1b of the cold storage and fixing or suspending the second pipe segment 2b to the ceiling 1a of the cold storage 1. The cold storage 1 may be configured to store perishable foods, beverages, medicines, biological matter, waste, or temperature sensitive chemicals.

[0029] A method for dehumidifying a cold storage is next described. The method includes providing a device according to the invention, as described hereinbefore. Next, the ventilator 6 is operated, to draw air from outside the cold storage 1 through the inlet 3 and towards the outlet 4. When flowing in the first pipe segment 2a, the air cools due to the cooling effect of the surrounding cold storage 1. Consequently, liquid comprised in the cooling air condenses and collects in the first pipe segment 2a. The liquid then flows back towards the inlet 3, under the influence of gravity. Driven by the ventilator 6, the partly or wholly dehumidified air then flows into the segment pipe segment 2b. The dehumidified then draws humidity from the surrounding cold storage 1, through the one or more apertures 5, and into the second pipe segment 2b. Thereby humidity is extracted from the cold storage 1. Advantageously, lower humidity levels within the cold storage are thereby achieved, leading to less growth of mold or fungus and / or to a reduced need for de-icing of the cold storage.

List of references

[0030]

1 cold storage

1a ceiling

1b sidewall

2a first pipe segment

2a’ inlet portion

2a’’ extending portion

2a’’’ returning portion

2b second pipe segment

3 inlet

4 outlet

5 aperture

6 ventilator

7 insulator

8 heating cable

9 drain

10 external drainage pipe

11 coupling

12 heating element

Claims

1. A device for dehumidifying a cold storage (1), the device comprising:

- a first pipe segment (2a) and a second pipe segment (2b), connected to one another;

o the first pipe segment (2a) comprising an inlet (3) for the inflow of air from outside the cold storage (1), and extending upward from the inlet (3); characterized by o the second pipe segment (2b) comprising an outlet (4) for the outflow of air to outside the cold storage (1), and one or more apertures (5) for the inflow of humidity from the cold storage (1) into the second pipe segment (2b); and

- a ventilator (6) for generating an airflow from the inlet (3) to the outlet (4).

2. The device according to claim 1, wherein the first pipe segment (2a) extends upward from the inlet (3) at an angle α with respect to the horizontal direction, where 0 < α ≤ 90°, preferably 30 ≤ α ≤ 60°.

3. The device according to claim 1, comprising at least two apertures (5), preferably at least three apertures (5), the apertures (5) being arranged equidistantly (preferably) along the length of the second pipe segment (2b).

4. The device according to any of claims 1 - 3, wherein the first pipe segment (2a) and the second pipe segment (2b) comprise a T-shaped cross section.

5. The device according to any of claims 1 - 4, further comprising a heating cable (8), arranged along the length of at least the second pipe segment (2b).

6. The device according to any of claims 1 - 5, further comprising a drain (9), wherein the drain (9) is configured to be connected to an external drainage pipe (10).

7. The device according to any of claims 1 - 6, further comprising a coupling (11) connecting the first pipe segment (2a) to the second pipe segment (2b), wherein the coupling (11) optionally comprises a heating element (12).

8. A cold storage (1) comprising a device according to any one of claims 1 – 7.

9. A cold storage (1) according to claim 8, wherein

- the first pipe segment (2a) traverses a side wall (1b) of the cold storage (1) and the inlet (3) is arranged outside the cold storage (1); and

- the second pipe segment (2b) traverses a side wall (1b) of the cold storage (1) and the outlet (4) is arranged outside the cold storage (1).

10. A cold storage (1) according to any one of claims 8 – 9, wherein the cold storage comprises a cold storage cabinet, a cold storage container, a cold storage transport vehicle, a cold storage room, or a cold storage hall, such as a refrigerated warehouse or refrigerated distribution center.

11. A method for dehumidifying a cold storage (1), the method comprising:

- providing a device according to any one of claims 1 - 7 or a cold storage (1) according to any one of claims 8 - 10;

- activating the ventilator (6) to generate an airflow from the inlet (3) to the outlet (4);

- dehumidifying air in the first pipe segment (2a), by cooling and condensing humidity comprised therein;

- re-humidifying air in the second pipe segment (2b), by drawing humidity from the cold storage (1) through the at least one aperture (5); and

- expelling re-humidified air from the device through the outlet (4), thereby dehumidifying the cold storage (1).