NL2019470B1

NL2019470B1 - Cooling cabinet and method for operating the cooling cabinet

Info

Publication number: NL2019470B1
Application number: NL2019470A
Authority: NL
Inventors: Roland Ten Houten Maarten; Johannes Wessem Schols Berend
Original assignee: Coolfinity Ip B V
Priority date: 2017-08-31
Filing date: 2017-08-31
Publication date: 2019-03-11
Also published as: MX2020002355A; CN111433539A; EP3676547A1; PH12020550071A1; JP2020532706A; BR112020004008A2; KR20200059231A; WO2019045565A1

Abstract

A method is provided for operating a cooling cabinet arranged for cooling matter in the cabinet. The cabinet for use With this method comprises a storage space for holding the matter, a compressive cooling system comprising at least a first compressor, a primary evaporator that is for at least a substantial part fully surrounded by a phase change material provided in a container, an air displacement module and a secondary evaporator. The method comprises operating the primary evaporator via the compressor until the cooling cabinet reaches a pre-determined state and operating the air displacement module for providing a forced air flow to flow along an outer surface of the container and subsequently through the storage space. Upon the cooling cabinet reaching the pre-determined state, the secondary evaporator is operated for controlling the state of the cooling cabinet.

Description

TECHNICAL FIELD

The various aspects and embodiments thereof relate to a cooling cabinet and a method of operating such cooling cabinet. More in particular, the various aspects and the embodiments relate to a cooling cabinet comprising a cold storage.

BACKGROUND

Refrigerators and freezers commonly work by means of compressive cooling: a liquid coolant is evaporated in an evaporator duct using an expansion valve. Due to the expansion, the temperature of the coolant in the evaporator duct reduces rapidly. This decrease of temperature is used for cooling matter in the refrigerator or freezer. The evaporated coolant is compressed and fed to a condenser to return to a liquid state.

The evaporator is commonly provided in a space for storing goods to be maintained at low temperatures or very close to that space, only separated by a thin wall. For cooling the goods, the compressor of the cooling circuit switches on and off. This leads to steep fluctuations of temperatures in the inner space of the refrigerator. For goods that require closely controlled temperature, this may be an issue.

Furthermore, in absence of primary power, temperature may rise fast despite proper insulation that may be provided in the housing of the refrigerator.

UK patent application GB 2514622 discloses a refrigerated cabinet having a first evaporator to cool the air in the cabinet. The cabinet further comprises a cold thermal store to be able to cope with high cooling loads. A phase change material acting as a thermal store is cooled by second evaporator through which refrigerant flows. To this end, the second evaporator may be partially enveloped within the phase change material. In normal operation, the first evaporator is operated to cool the cabinet. When the refrigerator experiences a high cooling load, both the first evaporator and the thermal store can be used simultaneously to cool the air.

By operating the first evaporator by default for cooling the air in the refrigerator, the temperature may locally drop below a target temperature due to direct exposure of the evaporator to the space in the cooling cabinet, which may result in cooling matter to a level that is too low. This may affect quality of the matter.

SUMMARY

It is preferred to provide a cooling cabinet and a method of operating a cooling cabinet that provides a more stable temperature control and provides a stable and relatively long cooling performance even in case of a power rupture.

A first aspect provides a cooling cabinet for cooling matter. The cooling cabinet comprises a first storage space for storing matter to be cooled, a first compressor for compressing a coolant material, a primary evaporator for evaporating the coolant material compressed by the compressor and a cold storage comprising a container for holding a phase change material and at least part of the primary evaporator. The cooling cabinet further comprises a secondary power source, a first air displacement module arranged to be powered by a primary power source and/or the secondary power source and arranged to provide a first air flow having a first, flow rate flowing along an outer surface of the container of the cold storage and subsequently to the first storage space; and a controller arranged to detect that insufficient power is provided by the primary power source for operating the air displacement module and arranged to power the air displacement module by means of the secondary power source.

This embodiment further comprises secondary power source, preferably a battery or a solar panel, arranged to provide power to the first air displacement module upon determination that the external source is not able to power the first compressor.

With a cold storage that is firstly brought to its desired state - for example frozen or at a temperature well below zero, at zero or at least for a small part slightly above zero - before actual operation of the cooling cabinet and preferably controlled to be kept in that state, only a forced air supply by means of the first air displacement module is required for keeping matter in the storage space cooled for a prolonged period without having to operate a compressor for providing compressed coolant to any evaporator. Hence, contrary to some cooling cabinets already known, battery power is not required to be used for a compressor. This is a considerable advantage, because - as already indicated above - a fan requires less power than a motor for compressive cooling.

The first aspect also provides a cooling cabinet for cooling matter. The cooling cabinet comprises a first storage space for storing matter to be cooled, a first compressor for compressing a coolant material, a primary evaporator for evaporating the coolant material compressed by the first compressor. The cooling cabinet further comprises a cold storage comprising a container for holding a phase change material and a first air displacement module arranged to provide a first air flow having a first flow rate flowing along an outer surface of the container of the cold storage and subsequently to the first storage space. In this cooling cabinet, any evaporator comprised by the cooling cabinet arranged to be operational for bringing the cooling cabinet to a state for cooling matter has at least a substantial part of the evaporator surrounded by the cold storage.

By embedding at least a very large part of the primary evaporator in phase change material, firstly the phase change material is cooled and preferably changed to solid prior to cooling the matter inside the cooling cabinet. An advantage to this is that firstly, energy is invested in saving for a cold reserve prior to cooling other matter.

Furthermore, bringing the cooling cabinet in an operation state by means of a bare evaporator of a cooling circuit means brute force cooling. This may result in temperature dropping below a target temperature at certain positions locally in the cooling cabinet. This, in turn, may seriously deteriorate the quality of certain goods in the cooling cabinet. For example, certain medicine that is to be kept from freezing may freeze and decay.

By firstly operating the primary evaporator for bringing the cold storage in operation state, a stable source for cold - a stable sink for thermal energy - is provided as compared to starting off by operating a bare tubeand-fins evaporator.

An additional advantage of the cooling cabinet according to this aspect is that upon powering up of the cooling cabinet, available energy is firstly invested in long term cooling capacity, rather than in fast operation of the cooling cabinet.

An embodiment of this aspect comprises a first sensor for determining a state of the cooling cabinet, a secondary evaporator having at least a substantial part not embedded in a phase change material and a processing unit coupled to the sensor. In this embodiment, the processing unit is arranged to operate the first compressor for providing compressed coolant material to the primary evaporator and upon detecting, by means of the sensor, that the cooling cabinet is in a pre-determined state, operate either the first compressor or a second compressor for providing compressed coolant to the secondary evaporator.

A second aspect provides a method of operating a cooling cabinet arranged for cooling matter in the cabinet, the cabinet comprising a storage space for holding the matter, a compressive cooling system comprising at least a primary compressor, a primary evaporator that is for at least a substantial part surrounded by a phase change material provided in a container, a secondary power source and an air displacement module arranged to be powered by a primary power source and the secondary power source. The method comprises operating the primary evaporator via the compressor until the cooling cabinet reaches a pre-determined state, operating the air displacement module via the primary power source for providing a forced air flow to flow along an outer surface of the container and subsequently through the storage space. In response to detecting that insufficient power is provided by the primary power source for operating the air displacement module, the air displacement module is powered by means of the secondary power source.

In an embodiment, the cooling cabinet further comprises a secondary evaporator, the method further comprising operating the secondary evaporator for aiding in controlling the state of the cooling cabinet until the cooling cabinet reaches the pre-determined state.

By firstly operating the primary evaporator, a storage of cold matter - a sink for thermal energy - is firstly created. Building up this cold storage provides a basis for stable cooling of matter in the cooling cabinet. Once the desired state of the cold storage is reached, for example a particular temperature is reached or a phase change material comprised by the cold storage is in a particular phase, a stable operation of the cooling cabinet is reached. In this stable state, the secondary evaporator may be operated, in conjunction with other parts of a cooling circuit like a compressor, condenser and expansion valve, for providing cool air to control temperature in the cooling cabinet, optionally aided by the fan.

In case of power rupture, preferably neither of the evaporators will be operated if no power is available to one or more compressor for operating a cooling circuit. Using this method means that with power available, firstly thermal energy is withdrawn from the cold storage, rather than directly from the cabinet. In this way, temperature within the cooling cabinet is kept stable or at least safeguarded from large fluctuations in temperature and available energy is firstly invested in providing cooling capacity on the longer term, rather than directly. This results in a long holdover time, i.e. a long time during which goods in the cabinet may be cooled without active cooling.

An embodiment comprises detecting whether a primary power supply for powering the compressor provides electrical energy and, if the primary power supply is detected not to be able to power the compressor, powering the air displacement unit by means of a secondary power source comprised by the cooling cabinet.

In another embodiment, the secondary evaporator is not operated until the pre-determined state is reached.

By firstly investing power in a cold storage rather than in direct cooling, the cold storage provides a heat sink that may be used for a longer period. This is particularly advantageous in this embodiment, as this reduces or even eliminates using power of a secondary power source like a battery for operating one or more compressors of compressive cooling. By powering the fan and preferably not any coolant compressor, stable and continuous cooling is provided to goods stored in the storage space. This is particularly advantageous as a motor of a fan consumes less energy than an electromotor of a compressor of a cooling circuit.

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BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects and embodiments thereof will now be discussed in further detail in conjunctions with drawings. In the drawings:

Figure 1 A: shows an embodiment of a cooling cabinet;

Figure 1 B: shows another embodiment of a cooling cabinet;

Figure 2: shows a first flowchart depicting an embodiment of operation of the cooling cabinet as depicted by Figure 1 A;

Figure 3: shows a second flowchart depicting an embodiment of operation of the cooling cabinet as depicted by Figure 1 A or Figure 1 B;

Figure 4: shows a third flowchart depicting an embodiment of operation of the cooling cabinet as depicted by Figure 1 A or Figure 1 B;

Figure 5: shows a further embodiment of a cooling cabinet;

Figure 6 A: shows a first cold storage module; and.

Figure 6 B: shows a second cold storage module.

DETAILED DESCRIPTION

Figure 1 A shows a refrigerator 100 as a cooling cabinet. In this embodiment, the refrigerator 100 is arranged for cooling items 112 stored on shelves 110 in a cooling space 106. Discussion of these embodiments here does not preclude implementation of the various aspects and embodiments thereof in a cooling cabinet for freezing the items 112 rather than cooling them. An important difference between cooling and freezing is that with cooling, the temperature of the items 112 is to be above zero degrees centigrade and below zero degrees centigrade for freezing. Yet, both principles rely on withdrawing thermal energy from the items and keeping the temperature of any medium in the cooling space 106 at substantially the same temperature: the intended temperature of the items 112.

Within the refrigerator 100, an inner lining 104 is provided, preferably comprising an insulating layer, for defining an inner space in the refrigerator 100. Within the inner space, a separation wall 114 is provided for dividing the inner space in a storage space 106 and a cold storage space 116. The storage space 106 and the cold storage space 116 are in fluid communication with one another, preferably at an upper end and a lower end of the separation wall 114. The separation wall 114 may be provided as 5 a contiguous barrier; alternatively, the separation wall 114 may comprise through holes between the lower end and the upper end of the separation wall 114, thus providing for example a mesh structure with small holes provided in a regular or irregular grid. Such mesh structure is particularly advantageous for use for a large cooling cabinet or a cooling wall in for example a supermarket.

In the cold storage space 116, a container 120 is provided for holding a phase change material. A phase change material may be characterised as a substance with a high heat of fusion which, melting and solidifying at a certain temperature, is capable of storing and releasing large 15 amounts of energy. Heat is absorbed or released when the material changes from solid to liquid and vice versa; thus, phase change materials are classified as latent heat storage units. In the embodiments discussed here, the phase change material is water, other phase change materials may be envisaged for use as well, such as glycol.

In a preferred embodiment, the container 120 is provided comprising a resilient material, at least for a substantial part. As water expands when it solidifies due to decrease of temperature, more space is required for holding the phase change material. Using resilient material allows the container 120 to expand upon solidification of the phase change material without providing potentially destructive strain on the walls of the container 120. The resilient material is preferably a polymer such as an organic polymer like polyethylene. An advantage of using such organic polymer is that is has a relatively low thermal conductivity. As a result, it can have a relatively large temperature drop ΔΤ between the phase change material inside the container 120 and the air of the cold storage space 116 flowing along an outer surface part of said container 120. An advantage of this embodiment is that the phase change material may be cooled well below a particular temperature, while the air just outside the container may be at a higher temperature. In another embodiment, the container may, additionally or alternatively, be open at the top and/or provided with an expansion system.

The container 120 preferably takes up at least 5% and preferably at least 10% of the space defined by the inner liner 104 and, if present, a door 108. If the cold storage is provided in a modular fashion, with two or more containers optionally provided each with their own evaporator or with their own part of a common evaporator, the total of the containers with the phase change material takes up at least 5% and preferably at least 10% of the inner space of the refrigerator 100.

If no door is present, the inner liner 104 is provided with a hole having a certain plane. In such cases, the space within the cooling cabinet 100 to be cooled is defined by the certain plane and the inner liner 104.

In another embodiment that may be combined, the container 120 has a surface area of at least 3 m², preferably at least 3.5 m², 4 m², 5 m², at least 6 m², at least 8 m², at least 10 m² and more preferably at least 12 m²or at least 16 m² per cubic metre of the space defined by the inner liner 104 or, alternatively, of the storage space 106.

To increase the surface area of the container 120, the wall of the container 120 may have a corrugated or otherwise shaped exterior. The container 120 preferably comprises openings at the top and at the bottom, for filling and emptying the container 120. In the embodiments shown here, the container is provided along the height in the space delimited by the inner liner 104. In another embodiment, the container is provided above or below the storage space 106.

Within the container 120, a primary evaporator 122 is provided for evaporation of a coolant. Any coolant may be used that is suitable for the methods discussed in this description. The primary evaporator 122 is at least for the majority of the evaporator and preferably for more than 65% embedded in the container 120 and in that way, surrounded by phase change material. In particularly preferred embodiments, the primary evaporator is for more than 70%, 75%, 80%, 85%, 90%, 95% and most preferably for 100% surrounded by phase change material. The primary evaporator 122 may be provided in a metal, either pure or alloy, like aluminium, steel, iron, other or a combination thereof. The primary evaporator 122 may be provided in direct contact with the phase change 10 material.

In a preferred embodiment, upstream and downstream ends of the part of the primary evaporator 122 that is provided in the container 120 are provided at the top of the container 120 to prevent or at least reduce any potential leakage risk at a container-evaporator interface. In one embodiment, the state sensor 148 is preferably provided at the downstream end of the part of the primary evaporator 122 that is embedded in the container 120. This is the least cold part of the evaporator part in the container 120 and therefore the state sensor 148 is provided near or at the last part of the phase change material that solidifies upon cooling. This embodiment is particularly advantageous if the desired state of at least most of the phase change material is just below the melting point.

Alternatively or additionally, the container 120 is provided with ducts, elongate cavities, tunnels or recesses running along the length of the container - from top to bottom as depicted by Figure 1 A or 1 B- for housing 25 ducts of the primary evaporator 122. The ducts may be circumferentially closed, or, alternatively, have a small opening at the side of the ducts for inserting the primary evaporator 122. Hence, the primary evaporator 122 is surrounded by an outer wall of the container 120 and as such, to a very large extent, preferably over 65%, embedded in the container. This means 30 that a small part of the evaporator ducts may be exposed directly to the cold storage space 116 along the length of the ducts, though this area is preferably kept as small as possible.

At least a substantial part of the primary evaporator 122 is thus embedded in the container 120 and in that way in the phase change material. The phase change material hence surrounds at least part of the primary evaporator 122. Surrounding should in this context be understood as at least comprising but not limited to extending around the primary evaporator for at least 65% of the outer cross section of the primary evaporator, seen in a horizontal cross section thereof, preferably at least 80%, more preferably at least 90% and most preferably entirely.

The primary evaporator 122 is provided in a first compressive cooling circuit that further comprises a first compressor 124, a first condenser 126 and a first expansion valve 128. The first expansion valve 128 is preferably placed close and more preferably as close as possible to the container 120. The first compressor 124, the first condenser 126 and preferably the first expansion valve 128 are preferably provided outside the inner space.

In another embodiment, the refrigerator 100 comprises a further container comprising a further primary evaporator for providing a further cold storage. The further cold storage may be provided in the cold storage space 116 or, alternatively, in a further separate cold storage space. The further primary evaporator may be part of a separate compressive cooling circuit. Alternatively, the further primary evaporator may be share one or more components of the first compressive cooling circuit, wherein the further primary evaporator is preferably provided parallel to the primary evaporator 122, or, alternatively, in series with the primary evaporator 122.

The refrigerator 100 further comprises an optional second cooling circuit. The second cooling circuit comprises a second compressor 134, a secondary evaporator 132, a second expansion valve 138 and a second condenser 136. The secondary evaporator 132 may be provided in the inner space, in either the storage space 106, the cold storage space 116, or both. Alternatively, the secondary evaporator 132 is provided directly adjacent to or is embedded in the inner liner 104 such that only a small layer of material of the inner liner 104 separates the secondary evaporator 132 from 5 the inner space as defined by the inner liner 104.

In an alternative embodiment, the first condenser 126, the first compressor 124 and/or the first expansion valve 128 are shared by the first cooling circuit and the second cooling circuit. Coolant from the first condenser 126 is distributed to either the primary evaporator 122 and/or the 10 secondary evaporator 132 by means of a three-way valve (not shown) and via the primary evaporator 122 and the secondary evaporator 132 led back to the first compressor 124.

The operation of the refrigerator 100 is controlled by means of a processing unit 140 provided in a housing 102 of the refrigerator 100. The 15 processing unit 140 is arranged to control the first compressor 124 and the second compressor 134. The processing unit 140 is connected to a first temperature sensor 142 provided in the cold storage space 116, preferably at the top thereof, a second temperature sensor 144 at the top of the storage space 106 and a third temperature sensor 146 at the bottom of the storage 20 space 106. The processing unit 140 is furthermore connected to a state sensor 148 for sensing a state of the phase change material in the container 120. The state sensor 148 may comprise a temperature sensor, a phase sensor determining a phase of the phase change material, another sensor, or a combination thereof.

The processing unit 140 is also connected to an electromotor 152 or other motor for driving a fan 154 as an air displacement module, to a power inlet 162 for receiving energy from a primary power source, preferably electrical energy, and to a secondary power source, preferably a battery 164 as internal energy storage. The primary power source may be a mains power 30 source, at 240 V AC or at 110 V AC in some countries. Alternatively or additionally, the primary power source may be solar power, with solar panels provided externally of the refrigerator 100 or provided on/in the outer walls of the housing 102 of the refrigerator 100.

The air displacement unit is arranged to provide an air flow in the storage space 106 from top to bottom and in cold storage space 116 from bottom to top. Alternatively, the air flow may be provided in a reverse direction.

A refrigerator or other type of cooling cabinet thus provided may be manufactured in any useful size, either for use in a supermarket or small for use such that it may be handheld and/or carried by a remote controlled unmanned vehicle, either moving through the air as an aircraft, helicopter, polycopter like a quadcopter or hexacopter, over land or over or under water.

Figure 1 B shows another refrigerator 100 as another embodiment of the cooling cabinet. In the refrigerator 100 depicted by Figure 1 B, the second cooling circuit has been omitted and the storage space 106 is solely cooled by means of at least one of the primary evaporator 122 and the phase change material comprised by the container 120.

In Figure 1 A and figure 1 B, solid lines have been provided to indicate control lines and dashed lines indicated a circuit for transporting coolant. Power lines have not been indicated, whereas power may be transferred over a control line.

Thus far, the cold storage module with the container 120 has been discussed as fixed within the cold storage space 116. In another embodiment, the cold storage module, either with or without the primary evaporator 122 and either with or without the further components of the primary cooling circuit, may be provided in a modular way such that it may be removed and/or replaced in relation to the refrigerator 100.

Figure 2 shows a first flowchart 200 depicting a method for operating the refrigerator 100 as depicted by Figure 1 A. The various parts of the first flowchart 200 are briefly summarised in the list below and are discussed in further detail after the list.

202 start procedure

204 operate primary cooling circuit

206 read state sensor

208 desired state reached?

210 stop primary cooling circuit

212 start secondary cooling circuit

214 read temperature sensor

216 temperature ok?

218 stop secondary cooling circuit

The procedure starts in a terminator 202 and proceeds to step 204 in which the primary compressor 124 is started. Subsequently, the state sensor 148 is read in step 206 to determine a state of the phase change material in the container 120. In step 208, the reading from the state sensor 148 is compared with a pre-determined value to verify whether a desired state of the phase change material is reached. Such desired state may be a particular temperature, either above or below zero degrees centigrade. Alternatively or additionally, such desired state may be that, at the location of the state detector 148, the phase change material is in the solid phase.

Upon the phase change material reaching the desired state, the procedure continues to step 210 from step 208. If the desired state is not reached, yet, the procedure returns to step 204, or, alternatively, to step 206.

In optional step 210, the first cooling circuit is stopped. Subsequently, in step 212, the second cooling circuit is started. In step 214, the temperature of at least one of the first temperature sensor 142, the second temperature sensor 144 and the third temperature sensor 146 is read. The temperature or temperatures read are compared with one or more reference values in step 216. If the temperatures or temperatures read are equal to or below the one or more reference values, the second cooling circuit is stopped in step 218. Subsequently, the process branches to step 214 for reading the temperature. This loop may comprise a waiting step.

If the temperature or temperatures read are equal to or higher than the one or more reference values, the process branches back to step 212 in which the second cooling circuit is continued to run. Optionally, the process also branches back to step 204 or step 206 to restart operation of the first cooling circuit or at least check whether the phase change material in the container 120 is still in the desired state. If the latter is not the case, the first cooling circuit is operated to bring the phase change material to the desired state.

Figure 3 shows a second flowchart 300 depicting an embodiment for operation the refrigerator 100 as depicted by Figure 1 A or Figure 1 B. The various parts of the second flowchart 300 are briefly summarised in the list below and are discussed in further detail after the list. The procedure depicted by the second flowchart 300 may be combined with the procedure depicted by the first flowchart 200.

302: start procedure

304: receive primary power

306: operate active components including compressors

308: charge battery

310: check primary power

312: power available?

314: operate fan on battery

The procedure starts in a terminator 302 and proceeds to step 304 in which power from an external source is received. Such power is preferably electrical power, received from the main electricity net or from a local source of power, including, but not limited to, an external solar panel or a generator, either powered by human power, wind power, a combustion engine, other, or a combination thereof.

The procedure continues to step 306, in which the refrigerator 100 is operated in a normal operating state. In such normal operating state, the procedure depicted by the first flowchart 200 may be executed. In parallel, the battery 164 is charged in step 308.

In step 310, the processing unit 140 determines whether power still is received from a primary power source via the power inlet 162. Such determination may be provided in a direct way, for example by measuring current and/or voltage of the primary power source. Alternatively or additionally, availability of sufficient power provided by the primary power source may be determined indirectly. Such indirect method for determining whether sufficient power is available from the primary power source is by checking a scheme of power availability, for example from a mains power supply, to a clock or other timer comprised by for example the processing unit 140. Additionally or alternatively, the timer may be used to operate from the primary power source at moments when a significant amount of green energy is available or, alternatively or additionally, off peak times. Additionally or alternatively, power from the primary power source may be interrupted by means of a switch that may be operated manually. Detection of lack of power from the primary power source may be detected via the switching action and/or absence of sufficient current and/or voltage.

Based on this determination, in step 312, a power reading or power detection signal is checked to a pre-determined state or value. If this check indicates primary power is available or at least sufficient primary power is available for normal operation, the procedure returns to step 306 and step

308. If this is not the case, operation of the first cooling circuit and the second cooling circuit is halted and the electromotor 152 powering the fan 154 is started using energy stored in the battery 164 in step 314, until again energy is received from a primary power source. To that end, the procedure continues to step 310 after step 314. Alternatively, at least one of the first cooling circuit and the second cooling circuit is operated through the battery 164 as a secondary power source.

Figure 4 shows a third flowchart 400 depicting an embodiment for operation the refrigerator 100 as depicted by Figure 1 A or Figure 1 B. The various parts of the third flowchart 400 are briefly summarised in the list below and are discussed in further detail after the list. The procedure depicted by the third flowchart 400 may be combined with the procedure depicted by the first flowchart 200 and the second flowchart 300. Referring to the second flowchart 300, the procedure depicted by the third flowchart 400 may be executed while receiving power from an external source as well as while using power provided by the battery 164.

402: start procedure

404: start fan

406: read temperature

408: too high?

410: increase fan activity

412: too low?

414: decrease activity

416: continue operation

The procedure starts in a terminator 402 and continues to step 404 in starting the electromotor 152 of the fan 154 in step 404. In step 406, a temperature is read. This may be a temperature read by one or more of the first temperature sensor 142, the second temperature sensor 144, the third temperature sensor 146.

The temperature readings are checked in step 408. If in step 408 it is determined that one or more of the detected temperatures are on or above a pre-determined value, the activity of the fan 154 is increased in step 410. This results in more cold air being provided to the storage space 106. Subsequently, the procedure continues to step 412. If one or more of the sensed temperatures is not at or below the pre-determined value, step 410 is bypassed.

If in step 412 it is determined that one or more of the detected temperature is on or below a pre-determined value, the activity of the fan 154 in decreased in step 414. This results in less cold air being provided to the storage space 106. Subsequently, the procedure continues to step 416. If one or more of the sensed temperatures are not at or above the predetermined value, step 414 is bypassed. In step 416, normal operation of the fan 156 is continued as set and the procedure loops back to step 406.

In this embodiment, the speed of the electromotor 152 driving the fan 154 is assumed to be controlled and may be increased or decreased. In another embodiment, this may not be the case. In such embodiment, the temperature control is preferably executed using hysteresis control: in a particular temperature range, no action is taken for temperature control. If the temperature is at the top of or above the range, the fan is operated until the temperature is at the bottom of or below the range and subsequently halted.

Figure 5 shows another refrigerator 500 as a cooling cabinet. The refrigerator 500 comprises a first storage space 512 and a second storage space 516. The storage spaces are separated from one another by a barrier 510. In the refrigerator 500, a cold storage space 506 is provided for housing a container 520 carrying a phase change material. In the container, substantially fully surrounded by the container and thus by the phase change material in the container, an evaporator 522 is provided. The evaporator 522 forms part of a compressive cooling circuit, which is not shown to simplify the drawing; it is present in a way similar to as depicted by Figure 1 A.

In a conduit between the cold storage space 506 and the first storage space 512, a first air displacement module 514 comprising a fan and an electromotor is provided for providing an air flow from the cold storage space 506 to the first storage space 512. At the bottom of the first storage space, another conduit is provided between the first storage space 512 and the cold storage space 506 for providing an air flow back to the cold storage space 506. In another embodiment, the air flow runs the other way around.

In a conduit between the cold storage space 506 and the second storage space 516, a second air displacement module 518 comprising a fan and an electromotor is provided for providing an air flow from the cold storage space 506 to the second storage space 516. At the bottom of the second storage space, another conduit is provided between the second storage space 516 and the cold storage space 506 for providing an air flow back to the cold storage space 506. In another embodiment, the air flow runs the other way around.

By adjusting air flow rates of each of the first air displacement unit 514 and the second air displacement unit 516, amounts of cool air from the cold storage space 506 may be provided independently from one another to the applicable storage spaces. This allows the temperatures of the first storage space 512 and the second storage space 516 to be controlled independently in accordance with the procedure as depicted by the third flowchart 400 for each storage space. In this way, the first storage space 512 may be used as a freezer and the second storage space 516 may be used as a refrigerator - or the other way around.

The various embodiments discussed above may be used in conjunction with one or more of the following numbered aspects and embodiments:

1. Cold storage module for use in a cooling cabinet, the module comprising:

A container for holding a phase change material;

A detector for detecting a surface level of the phase change material in the container;

Wherein the detector is arranged to generate a signal if the surface of the phase change level is at a pre-determined surface level.

2. Cold storage module according to embodiment 1, further comprising a float arranged to engage with the detector such that the detector generates the signal if the surface of the phase change material is at the pre-determined surface level.

3. Cold storage module according to embodiment 1 or 2, wherein the horizontal cross-section of the container narrows towards the top of the container.

4. Cold storage according to embodiment 3, wherein the horizontal cross-section of the container has a step function.

5. Cooling cabinet comprising:

A cold storage module according to any of the embodiments 1 to 4;

An evaporator for providing compressive cooling provided in the container of the cold storage module; and a controller coupled to the compressor and the detector of the cold storage module and arranged to perform at least one of:

start compressor operation if the level of the phase change material is at the pre-determined surface level; and

Stop compressor operation if the level of the phase change material is above or below the pre-determined surface level.

Figure 6 A shows a cold storage module 600 comprising a container 610 for holding a phase change material. In the container 610, phase change material is provided with a surface at level 612. As the phase change material changes from solid to liquid and vice versa, the relative mass changes. And with change of relative mass, the volume of the amount of phase change material changes.

If the phase change material comprises water or is water, the volume of the amount of phase change is larger in solid state than in hquid state. Hence, when the phase change material is solid, the level 612 is higher compared to when the phase change material is liquid. The cold storage module 610 may be used in any of the cooling cabinets as discussed above.

In the container 610, on or partially in the phase change material, a floater 626 is provided. In this embodiment, the floater is via a beam hingedly connected to a connection point 622 connected to the container 610 or otherwise connected to the refrigerator. As the surface level 612 of the phase change material rises or lowers, the floater 626 rises or drops.

The beam 624 hinges accordingly and the hinging movement and with that, the position of the floater 626 may be determined by means of a sensor comprised by the connection point 622. In response thereto, the sensor comprised by the connection point 622 may generate a signal providing information on the surface level 612 of the phase change material. And this provides information on the state of the phase change material: liquid, hquid and solid or fully solid. As such, the floater 626 and the sensor comprised by the connection point 622 may replace the state sensor 148 as depicted by Figure 1 A.

Alternatively or additionally, a push button 634 provided in a housing 632 with a circuit switch may be provided. If the floater 626 is at a pre-determined level, it engages with the push button 634 and with that, the circuit switch may open or close a circuit. In a preferred embodiment, the pre-determined level matches with a situation in which all or at least most of the phase change material is solid.

In a preferred embodiment, in which water is used as phase change material, the processing unit 140 is arranged to halt operation of the first, compressor 124 (Figure 1 A) if the floater 626 is at a level at which all or at least most of the water is frozen.

In other embodiments, other phase change materials may be used that have a higher density in solid than in liquid. In such embodiments, operation of the first compressor 124 may be stopped if a particular lower level of the surface of the phase change material is reached. This may also be detected by means of the floater 626 and an appropriate sensor.

Figure 6 B shows a further cold storage module 650 as another embodiment. The cold storage module 650 comprises a container 660 having a step section 664 at the top of the container 660. The transition may be sharp or, alternatively or additionally, smoothed and curved as with a wine bottle. In the container 660, a phase change material is provided up to a surface level 662. In the container 660, phase change material provided such that the surface of the phase change material is within a narrow section at the top of the container 660. In this way, volume changes of the phase change material result in a larger deviation of the surface level 662 compared to a container in which the horizontal cross-section of the container is substantially the same over substantially the full height of the container. With such larger movements of the floater 676 between the two phases, more accurate state detection is possible.

On the phase change material or partially in the phase change material, a floater 676 is provided. Above the floater 676, a switch in a housing 686 is provided with a push button 682 for actuating the witch. The push button 682 is arranged to engage with the floater 676 as discussed in conjunction with the embodiment of Figure 6 A.

Alternatively or additionally to the floater mechanisms, also other devices for detecting the surface level and with that, of the volume of the phase change material may be used. Hence, also other sensors may be used for determining volume of the phase change material and in that way, the state of the phase change material: liquid, liquid and solid or fully solid. Another sensor that may be used is a conductivity sensor. Such conductivity sensor may be provided at a lowest level of the phase change material reached at a particular state and alternatively or additionally at a highest level.

Upon detecting change of conductivity, the sensor is emerged or in contact with the phase change material or is out of the phase change material. The processing unit 140 may take action accordingly by switching off the first compressor 124 if all phase change material is determined to be solid or switch on the first compressor 124 if the phase change material is liquid as a whole or for at least a specific amount, for example for 2%, 5%, 10%, 15% or 20%.

In Figure 6 A, the container 610 is provided as a closed container and in Figure 6 B, the container 660 is provided as an open container. Alternatively, all containers may be either open, partially open or fully closed at the top.

In the description above, it will be understood that when an element such as layer, region or substrate is referred to as being “on” or “onto” another element, the element is either directly on the other element, or intervening elements may also be present. Also, it will be understood that the values given in the description above, are given by way of example and that other values may be possible and/or may be strived for.

Furthermore, the invention may also be embodied with less components than provided in the embodiments described here, wherein one component carries out multiple functions. Just as well may the invention be embodied using more elements than depicted in the Figures, wherein functions carried out by one component in the embodiment provided are distributed over multiple components.

It is to be noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting examples. For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words 'a' and 'an' shall not be construed as limited to 'only one', but instead are used to mean 'at least one', and do not exclude a plurality.

A person skilled in the art will readily appreciate that various parameters and values thereof disclosed in the description may be modified and that various embodiments disclosed and/or claimed may be combined without departing from the scope of the invention.

It is stipulated that the reference signs in the claims do not limit the scope of the claims, but are merely inserted to enhance the legibility of the claims.

Claims

Conclusions

Cooling device for cooling matter, comprising:

- A first storage space for storing matter that needs to be cooled;

- A first compressor for compressing a refrigerant;

- A primary evaporator for evaporating the refrigerant compressed by the compressor;

A cold storage comprising a container for holding a phase transition material and at least part of the primary evaporator;

- a secondary power source;

- a first air displacement unit arranged to be driven by a primary power source and / or the secondary power source and arranged to provide a first air flow with a first flow flowing along an outer surface of the cold storage container and then to the first storage space; and

- a controller arranged to detect that insufficient power is being supplied by the primary power source for driving the air displacement module and arranged to drive the air displacement module by means of the secondary power source.

2. A cooling device for cooling matter, comprising:

- A first storage space for storing matter that needs to be cooled;

- A first compressor for compressing a refrigerant;

A cold storage comprising a container for holding a phase transition material; and

- a first air displacement unit arranged to provide a first air stream with a first flow rate flowing along an outer surface of the cold storage container and then to the first storage space;

Wherein each evaporator is comprised by the refrigeration device which is arranged to be operational for placing the refrigeration device in a matter-cooling state having at least a substantial portion of the evaporator surrounded by the cold store.

The cooling device of claim 1 or claim 2, further comprising:

- a first sensor for determining a state of the cooling device;

A secondary evaporator comprising at least a substantial part not embedded in a phase transition material; and

- A processing unit linked to the sensor;

Where the processing unit is set up for:

- Operating the first compressor to supply compressed refrigerant to the primary evaporator;

upon detection, by the sensor, that the refrigeration device is in a predetermined state, or drive the first compressor or a second compressor to supply compressed refrigerant to the secondary evaporator.

The cooling device of claim 3, wherein the predetermined state is at least one of the following:

- The temperature in the storage space is equal to or less than a predetermined temperature;

- A predetermined amount or more of the phase transition material has passed into a predetermined phase; or

- The temperature of the outer surface of the container is equal to or less than a predetermined temperature.

Cooling device according to any one of claims 1 to 4, wherein the container comprises a resilient material, preferably a polymer, even more preferably an organic polymer.

The cooling device according to any of claims 1 to 5, further comprising:

- a second storage room; and

- A second air displacement module arranged to provide a second air flow with a second flow that flows along an outer surface of the cold storage container and then to the first storage space.

The cooling device of claim 6, further comprising:

- A first temperature sensor for sensing temperature in the first storage space;

- a second temperature sensor for sensing temperature in the second storage space; and

- a processing unit;

In which the processing unit is arranged to:

- controlling the first air displacement unit in response to a signal from the first temperature sensor for controlling temperature in the first storage space; and

controlling the second air displacement unit in response to a signal from the second temperature sensor for controlling temperature in the second storage space.

The cooling device of any one of claims 2 to 7 as far as dependent on claim 2, further comprising:

- a power input for receiving energy from an external power source for energizing the first compressor;

- a sensor for determining whether the external source is able to provide sufficient power to operate the first compressor; and

- An internal power source, preferably a battery or a solar panel, arranged to supply power to the first air displacement module when it is determined that the external power source is unable to power the first compressor.

A refrigeration device according to any one of claims 1 to 8, wherein the container is provided in a container space which is at least partially separated from the storage space by a dividing shield comprised by the refrigeration device.

The cooling device of claim 9, wherein the separator shield includes openings.

A method of operating a refrigeration device adapted to cool matter in the device, the device comprising a storage space for storing matter, a compressed refrigeration system comprising at least a primary compressor, a primary evaporator which is at least a substantial part surrounded by a phase transition material provided in a container, a secondary power source and an air displacement module arranged to be powered by a primary power source and the secondary power source, the method comprising:

- operating the primary evaporator via the compressor until the cooling device reaches a predetermined state;

- operating the air displacement module via the primary power source to provide a forced air flow flowing along an outer surface of the container and then through the storage space; and

- In response to detecting that insufficient power is being supplied by the primary power source to operate the air displacement module, energizing the air displacement module by means of the secondary power source.

The method of claim 11, further comprising not operating the compressor via the secondary power source.

The method of claim 11 or 12, wherein the refrigeration device further comprises a secondary evaporator, the method further comprising operating the secondary evaporator to assist in controlling and preferably maintain the condition of the refrigeration device until the refrigeration device predetermined state.

The method of claim 13, wherein the secondary evaporator is not operated until a predetermined state is reached.

The method of any one of claims 11 to 14, wherein the predetermined state is at least one of the following:

- The temperature of at least part of the outer surface of the container through which the air stream is fed is equal to or less than a predetermined temperature.

The method of any one of claims 11 to 15, further comprising detecting whether a primary power source provides electrical energy for energizing the compressor and, if it is detected that the primary power source is unable to energize the compressor, energizing the air displacement unit by means of a secondary power source contained by the cooling device.

The method of claim 16, further comprising if it is detected

5 the primary power source cannot energize the compressor, not energize the compressor.

The method of any one of claims 11 to 17, further comprising:

10 - Feeling a temperature in the storage room;

- Performing at least one of the following:

- Increasing activity of the air displacement module when the sensed temperature is equal to or higher than a predetermined threshold value; and

15 - Decreasing activity of the air displacement module when the sensed temperature is equal to or less than a predetermined threshold.

1/5

100

Fig. 1 A

2/5

100

140 154 164

Fig. 1 B

3/5

300