CA3109464C - Cold generation and storage - Google Patents

Abstract

P1216-1CA ABSTRACT A system for generating and storing cold, comprising: a storage container for storing cold water and ice; and a cooling unit comprising: a cooling element positioned within the storage container, designed for having cooling refrigerant streamed within; and an electrically insulating layer having electrically conductive coating, and having electrical wiring laid over the layer, wherein the layer is larger than a projection of the cooling element on the layer along a line perpendicular to the layer, the layer positioned such that the cooling element causes ice to form on the layer, wherein applying current to the electrical wiring causes the layer to heat, thereby enabling ice formed on the layer to io release and float towards the top of the storage container. Date Recue/Date Received 2021-02-17

Description

COLD GENERATION AND STORAGE
FIELD OF THE INVENTION
[0001] The invention relates to the field of thermal energy storage in general, and to cold generation and storage in particular.
BACKGROUND

[0002] Thermal energy storage (TES) allows thermal energy to be stored and used io hours, days or months later, at scales ranging from the individual consumer, a building, a multiuser-building, a district, a town, a region, or the like.

[0003] Usage examples include balancing of energy demand between different hours, such that hot or cold are produced and stored during low electricity rate hours, and used on higher rate hours. Other uses, referred to as seasonal thermal energy storage include is storing summer heat for winter heating, or winter cold for summer air conditioning.

[0004] TES may be achieved with widely differing technologies. For example, hot storage media include masses of native earth or bedrock accessed with heat exchangers by means of boreholes, deep aquifers contained between impermeable strata;
shallow, lined pits filled with gravel and water and insulated at the top; eutectic solutions 20 and phase-change materials, or others.

[0005] Other sources of thermal energy for storage include heat produced with heat pumps from off-peak, lower cost electric power, a practice called peak shaving; heat from combined heat and power (CHP) power plants; heat produced by renewable electrical energy that exceeds grid demand and waste heat from industrial processes.
25 [0006] Cold storage media may include collecting cold water or ice tanks. When needed, water or another fluid can be streamed through or near the water or ice, cooled and used in cooling systems.
[0007] Heat and cold storage, both short term (e.g. hours) and seasonal, is considered an important means for cheaply using variable renewable energy sources, for purposes 30 of electricity production and integration of energy systems fed by renewable energy.
Date Recue/Date Received 2021-02-17 SUMMARY
[0008] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.
[0009] There is provided, in accordance with an embodiment a system for generating and storing cold, comprising: a storage container for storing cold water and ice; and a cooling unit comprising: a cooling element positioned within the storage container, designed for having cooling refrigerant streamed within; and an electrically-insulating io layer having electrically conductive coating, and having electrical wiring laid over the layer, wherein the layer is larger than a projection of the cooling element on the layer along a line perpendicular to the layer, the layer positioned such that the cooling element causes ice to form on the layer, wherein applying current to the electrical wiring causes the layer to heat, thereby enabling ice formed on the layer to release and is float towards the top of the storage container. Within the system, the cooling unit can further comprise a heat spreading member, the heat spreading member positioned between the cooling element and the layer. The system can further comprise a second electrically insulating layer having an electrically conductive coating, such that the cooling element is positioned between the layer and the second layer. Within the 20 system, the cooling unit can further comprise a second heat spreading member, the second heat spreading member positioned adjacent to the second layer. Within the system, the layer is optionally made of Kapton0 RS. Within the system, the second layer is optionally made of Kapton0 RS. Within the system, the layer optionally has thickness of at most 100 m. The system can further comprise a controllable switch for 25 closing a circuit such that current is applied to the electrical wiring.
The system can further comprise: a sensor for capturing at least one aspect of ice formed on the first layer and provide output; and a processor configured to analyze the output of the sensor and determine a time for applying current to the electrical wiring.
[0010] In addition to the exemplary aspects and embodiments described above, further 30 aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.
Date Recue/Date Received 2021-02-17 BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Exemplary embodiments are illustrated in referenced figures. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below.
[0012] Fig. 1A is a perspective view of an ice forming and storing container, in accordance with some exemplary embodiments of the disclosure;
[0013] Fig. 1B is a front view of the ice forming and storing container of Fig. 1A, in accordance with some exemplary embodiments of the disclosure;
to [0014] Fig. 2A is an illustration of a cooling unit, in accordance with some exemplary embodiments of the disclosure;
[0015] Fig. 2B is a top view of the cooling unit, in accordance with some exemplary embodiments of the disclosure;
[0016] Fig. 2C is an illustration of a heat spreading plate, in accordance with some exemplary embodiments of the disclosure;
[0017] Fig. 2D is an illustration of an electrically resistive layer and electrical wires laid thereon, in accordance with some exemplary embodiments of the disclosure;
[0018] Fig. 3A is an illustration of a flat layer, electrical wires laid thereon, and formed ice cap, in accordance with some exemplary embodiments of the disclosure;
[0019] Fig. 3B is a top view of the cooling unit and formed ice caps, in accordance with some exemplary embodiments of the disclosure; and [0020] Fig. 4 is a flowchart of a steps in a method for creating and storing cold, in accordance with some embodiments of the disclosure.
Date Recue/Date Received 2021-02-17 DETAILED DESCRIPTION
[0021] The disclosure relates to a system and a method for generating and storing cold, and using the same for cooling applications such as air-conditioning and refrigeration.
[0022] Known solutions exist for cold generation and storage. Some of the solutions include the generation of ice blocks or chunks, such that at a later time water or another fluid can be streamed next to the ice, cooled, and used for cooling applications.
[0023] Some common reasons for storing cold thermal energy include shifting the demand for electricity from the high rate peak demand hours to low demand, low rate hours. This enables a user to enjoy cooling on the higher rated hours, while avoiding the relevant charges of these hours and paying lower-rated electricity charges on other hours. The charges may be measured, for example, in $/kWh.
[0024] Another common reason for storing cold thermal energy is the aim to utilize the availability of renewable green energy sources such as sun and wind, by using photovoltaic solar cells and wind turbines. However, such sources are usually available only part of the time. For example, photovoltaic solar cells may be used only in daylight, and wind turbines are effective only when the wind blows. By storing thermal energy, the energy produced by such sources may be put to use also when the source itself is unavailable, thereby reducing usage of non-renewable polluting energy sources.
This is true for "stand alone" or local energy production, as well as for electricity from the electricity grid, where the thermal storage is activated by relevant signals from the grid ("smart grid").
[0025] Thus, producing ice when possible or when the rates are low, and using it for cooling at other times, can save energy or money. For example, ice (water) based cold thermal energy storage may make use of the water 334J/g solid-to-fluid latent heat capacity. Thus, one metric ton of ice, composed of plain tap water, can store about 93KWh of cooling thermal energy.
[0026] Some cold storage systems include components for standard refrigeration cycle, including a compressor, a condenser, a metering device (typically an orifice, an expansion valve or a capillary tube) and an evaporator. The refrigeration system may Date Recue/Date Received 2021-02-17 further comprise a thermally insulated tank for storing water or ice, the tank having therein a cooling element submerged in water. In some embodiments, the evaporator is the cooling element, also referred to as a cooling plate.
[0027] The cooling element is used to cool the fluid water in the insulated tank, and to 5 freeze it once the water reaches a temperature near zero degrees Celsius, thus a layer of ice is formed on the cooling element.
[0028] The ice formed on the cooling element has poor heat conductivity, in accordance with the following formula for conductive heat transfer:
, *A
(Eq. 1) q = K *At -L
wherein q is the heat flow rate; k is a constant; At is the temperature difference between the cooling element and the water temperature; A is the surface area of the cooling element; and L is the thickness of the ice layer separating the cooling element and the water. Thus, as the layer of ice thickens, the heat flow rate through the ice is reduced and the ice formation process slows down.
[0029] For example, using solar panels during sun hours, converting one metric ton of fluid water into solid ice in seven hours requires an average cooling rate of 13.3KW.
[0030] In the above example, using a 1 square meter flat cold element and applying the heat transfer equation, achieving a cooling power of 13.3 KW after the formation of lOmm ice thick layer over the 1 square meter flat cold element will require a temperature gradient (At) of 60.5 C between the cold element on one side and the fluid water on the other side of the ice layer, which may be impractical. Increasing the ice thickness, for example letting the ice layer to become 11 mm thick, will increase the temperature gradient At at the same proportion, i.e. to over 66 C which may be even less practical. It will be appreciated that the cooling power is equivalent to the heat flow rate: in a tank full of water, once ice started forming, it can be theoretically assumed that all the cooling power is used to freeze additional water. Practically, the ice layer between the cooling element and the water also cools down to sub-zero temperatures, which slows down further ice creation. A similar phenomenon can be seen in domestic refrigerators: when freezing water into ice cubes, the water cools to zero relatively fast, causing the creation of a thin layer of ice on the top of each cube. However, it takes Date Recue/Date Received 2021-02-17

6 additional significant time until the full volume of water freezes into ice cubes. The example above thus demonstrates that there is a need for a huge temperature gradient in order to achieve reasonable ice creation rate. Obtaining such low evaporating temperatures requires the usage of expensive refrigeration systems that may make the entire solution un economical.
[0031] As can also be seen from Eq. 1 above, having a cooling element with a large surface area, for example a cooling element with multiple curvatures, provides for fast initial ice formation. However, as the ice forms, the gaps between the bends fill with ice, thus reducing the surface area A, which again slows the ice formation.
io Alternatively, a very large cooling element may be used, but is also more expensive.
[0032] Thus, one technical problem of the disclosed subject matter is the need to periodically release the ice formed on or near the cooling element, and let the ice float towards the top of the tank. This will enable further ice formation to be more efficient, such that larger quantities of ice can be formed over time and used when needed.
is Releasing the ice may be challenging, since if the ice sticks to the cooling element even at a very small area, or a bend or another geometrical limitation prevents a part of the ice from floating, the whole block of ice will remain stuck to the cooling element and will not float, thus again slowing down the cooling process. Therefore, such cases should be avoided.
20 [0033] It will be appreciated that gradual heating of the cooling element, as may happen where heating is done by streaming hot fluid through the cooling element, causes areas of the ice that have already been released to be heated and melt further, until the last bit of ice-cooling element bond is melted.
[0034] Thus, another technical problem of the disclosed subject matter is the need to 25 provide heat for melting the ice such that the ice can be released, in a uniform manner to avoid unnecessary melting of the ice.
[0035] One technical solution of the disclosure relates to a method and device for cost effective, cold thermal energy storage. The method and device are based on a refrigeration cycle, composed of a compressor, a condenser, a metering device 30 (typically an expansion valve or capillary tube) and an evaporator. The refrigeration Date Recue/Date Received 2021-02-17

7 system cools a cooling element that is part of a cooling unit submerged in water, inside a thermally insulated water tank. The cooling element cools the fluid water in the insulated tank, and once the water reaches near zero Celsius temperature, the water freezes. As detailed below, the ice is then released from the cooling unit and collected for later use.
[0036] In some embodiments, the evaporator is a heat spreader type evaporator, which may be the cooling element, optionally comprising also a heat spreading member. The cooling element may be formed, for example as one or more tubes or flattened tubes, a cylinder, rolled bonded plates, or any other shape, such that the refrigerant is flowing io within the cooling element and cools it. The shape of the cooling unit is required to be such that by melting the ice formed adjacent to the cooling unit, the ice will be released and free to float, and will not stick or be "hooked" to the cooling element.
[0037] In further embodiments, the evaporator is used for cooling a secondary fluid, typically water with antifreeze solution. The cooled solution is cooled to a sub-zero is Celsius temperature and is circulated between the evaporator and a cooling element that is submerged in the cooled water tank. Once the water in the storage tank is cooled to about zero Celsius the same water freezing process is commended.
[0038] In both embodiments, a cooling unit that includes the cooling element may comprise a thin layer of electrically resistive heat conductive material, or a thin layer of 20 electrically resistive material having conductive coating applied thereto. The coating may be applied as paint, as another layer positioned attached to the electrically resistant layer, or the like. In some embodiments, the coating may be partial, for example not cover the whole layer but rather be laid in a pattern, for example warp and woof stripes.
The layer or coating may have electrical wires laid thereon.
25 [0039] Once the water within the tank cools to near zero Celsius degrees, for example 1-2 degrees, ice begins to form on the cooling unit including parts of the electrically resistive layer or the coating. As ice has poor heat conductivity, the thicker the ice layer is, the slower the ice formation process becomes. The cooling unit is designed such that after some ice is formed on the layer or coating, the electrically resistive layer or 30 coating can be heated by supplying current to the electrical wires, which causes some ice to melt, such that the ice layer releases, allowing the ice to naturally float to the top Date Recue/Date Received 2021-02-17

8 of the water tank. It will be appreciated that the electrically conductive coating thus serves as a resistive heater. If previous ice crystals or blocks are already floating at the top of the tank, the newly released ice layer floats as high as it can. Then, the direct contact of the layer or coating with the water is regained, and another ice forming cycle can start, thus achieving overall faster, energy efficient ice formation rate.
[0040] The cooling unit is designed such that when the cooling element is active, at least a certain amount of ice is formed on the layer before bonding with ice formed directly on the cooling element or on other parts of the cooling unit. This is useful in avoiding "hooking" of the ice over the cooling element. For this effect to be achieved, io the layer may be, for example, a flat film which extends beyond the cooling element. In other words, the layer may be larger than the projection of the cooling element on the layer. In some embodiments, since the layer is very thin, its edges may be strengthened by a rigid frame. The rigid frame may be made of heat insulating material which will not be cooled by the cooling element, such that ice will not form on the frame, thus is preventing the ice formed on the layer from bonding to ice formed on the cooling element.
[0041] In some embodiments, a heat spreading member made of thermal conductive material may be positioned between the cooling element and the layer. For example, the heat spreading member may be designed to correspond to the structure of the cooling 20 element on one side, such that the heat spreading member reduces the amount of ice that is formed on the cooling element, and to the electrically resistive layer on the other side. The layer may also be larger than the side of the heat spreading plate attached thereto.
[0042] In order to enable release of the ice formed on the layer, current may be 25 applied to the wires. The current will cause the coating of the layer to heat due to the electric conductivity of the coating, thus releasing the ice formed thereon.
[0043] The layer may provide electric insulation between the coating and the heat spreading member or the cooling element which are generally made of electrically conductive material such as copper or aluminum, thus preventing a short-circuit through 30 the heat spreading member or the cooling element. However, the layer may be extremely thin, and thus makes only a minor disturbance to the heat flow from the water Date Recue/Date Received 2021-02-17

9 to the cooling element. Due to the design, in which the layer is larger than the cooling element or the heat spreading layer attached thereto, the ice formed on the layer is easily released as it is separate from ice formed on parts of the cooling element or the heat spreading member that are in contact with the water.
[0044] The layer may be made of Kapton RS, which indeed comprises the required properties as detailed below.
[0045] 1. Due to its extreme thinness, such as 10-200 m, for example 50 m, it does not thermally insulate the cooling element from the water, thus causing practically no disturbance to the ice forming. However, even such thin layer of Kapton RS is sturdy i o and durable.
[0046] 2. Electrical insulation: since the cooling element may be made, for example, of copper or aluminum, it is a very good electrical conductor. Thus, activating an electrical heating system requires electrically insulating the cooling element from the heating element. If, for example, conductive paint would be applied directly to the is cooling element, the current would flow through the cooling element thus creating a short-circuit, without the heating element being heated. The Kapton RS thus provides the required electrical insulation between the cooling element and the electrified area.
[0047] 3. By laying the electrical wires on two opposite ends of the coating, once current is applied to the wires, the coating becomes a very thin heating element that 20 heats evenly, thus releasing the formed ice all over and allowing it to float.
[0048] It will be appreciated that materials other than Kapton may also be used, for example silicone, rubber, PET plastic, or the like. However, in order to provide the required electric insulation, such materials may have to be thicker than Kapton, thus reducing the heat transfer between the water and the cooling element.
25 [0049] One technical effect of the disclosure is a fast and efficient system and method for cold generation and storage, that create significant amounts of ice which can then be used for cooling purposes at other times. The system and method are designed to periodically release ice formed in a container, such that further water can make direct contact with cold elements and form more ice. The formed and released ice gathers at 30 the top of the container and is then ready for use. The specific structure, including the Date Recue/Date Received 2021-02-17 thin electrically insulating layer positioned between the cooling element and a heating element, e.g. the coating, provides for effective release of the formed ice, such that further ice can be formed at high rate, wherein the thinness of the layer does not disturb the ice forming.
5 [0050] Another technical effect of the disclosure is that the system and method can use renewable resources for cooling when available for producing and storing cold, and using the stored cold when the resources are unavailable, thus using renewable "green"
energy sources. Systems and devices in accordance with the disclosure may be incorporated into smart grids in which the grid communicate with the device and causes

10 it to start and stop.
[0051] The disclosure thus provides for generation and storage of cold in hours during which the full electricity generation facilities are not fully utilized, for example during night hours in hot countries. The cold can then be utilized during hours in which the demand is high, wherein said demand is currently supplied by polluting peaking power plants which emit excess carbon dioxide due to low energy efficiency.
Moreover, some of these plants are highly polluting due to their usage of polluting substances like mazut or diesel fuel.
[0052] Referring now to Fig 1A, showing an exemplary embodiment of a perspective view of an ice forming and storing container, and Fig. 1B, showing a front view of the same, in accordance with some embodiments of the disclosure.
[0053] Fig. 1A shows a container 100, which may be made of any sturdy material, such as metal, plastic, or the like. Container 100 may have an inner container 104, insulated from container 100 by insulation layer 106 made of any insulation material, such as fiberglass (specifically glass wool), cellulose, rock wool, polystyrene foam, urethane foam, vermiculite, perlite, cork, or others. In some embodiments, the external radius of the container may be several decimeters, for example between 50 and 150 cm, and the internal radios may be smaller in 5-20 cm, for example 10 cm, thus providing for 10cm of insulation.
[0054] Within container 104 are tubes 108 through which a refrigerant fluid may be streamed to and from cooling unit 114. Cooling unit 114 may comprise cooling element Date Recue/Date Received 2021-02-17

11 116, which may have attached thereto on either side, directly or indirectly, a thin electrically resistant layer 112. Layer 112 may have thereon electrically conductive coating and electrical wires. In some embodiments, layer 112 may be strengthened by a thermal insulating frame.
[0055] The system may further comprise a feedback mechanism or a sensor for estimating the amount of ice formed on layer 112, or whether a sufficient amount has been formed within the container. The system may also comprise a controllable switch (not shown), for closing a circuit such that current is applied to the electrical wires when it is determined that a sufficient amount of ice has been formed on the layer and io should be released. When applying current, the refrigeration may be stopped, for enhancing the ice release process and saving energy.
[0056] It will be appreciated that a cooling system may comprise additional components positioned externally or internally to container 100, such as a compressor, condenser, metering device, or the like.
[0057] Referring now to Fig. 2A, showing a more detailed view of an embodiment of cooling unit 114, in accordance with some embodiments of the disclosure.
[0058] Cooling unit 114 may comprise cooling element 116, heat spreading plates 204, and layer 112.
[0059] Cooling element 116 may be formed as a spiral tube as shown in Fig. 2A, flattened tube, or the like. In further embodiments cooling element 116 may comprise two metal plates made for example from aluminum, copper, or the like, that are rolled-bonded together with the refrigerant channels embedded between, or the like.
The spiral tube shown on Fig. 2A may comprise straight parts 202 and bends 203.
[0060] Cooling unit 114 may also comprise one or more heat spreading plates 204, designed to correspond to and be attached to cooling element 116 along straight parts 202. Plates 204 may therefore reduce the contact area of cooling element 116 with the water, and thus the amount of ice formed thereon, which ice is hard to release.
However, plates 204 may transfer the heat from the water to the cooling element, thereby transferring cold from cooling element 116 to the water. Heat spreading plates Date Recue/Date Received 2021-02-17

12 204 may be of any heat conductive material, such as aluminum, copper, any other metal, or the like.
[0061] Fig. 2B shows a top view of the cooling unit, including cooling element 116, heat spreading plates 204 and layers 112.
[0062] Fig. 2C shows an exemplary embodiment of heat spreading plate 204 and layers 112. Heat spreading plate 204 has thereon grooves 206 corresponding to straight parts 202 of cooling element 116 which is formed as a spiral tube.
[0063] Layer 112 may be made of a thin electrically resistant polyimide film, such as a film of Kapton 0. The film may be made of Kapton 0 RS, which has thereon io electrically conducive coating. Layers 112 may be positioned such that the coating is on the side of the film far from heat spreading plate 204. Kapton 0 RS may have surface electrical resistivity of 100 ohms/sq. and Tensile Strength larger than 100 MPa. Kapton 0 RS may be resilient to high range of temperatures. The thickness of layer 112 may be, for example, 50 m. Thus, layer 112 does not thermally insulate between heat is spreading plate 204 and the water.
[0064] In other embodiments, layer 112 may be made of Silicone Rubber or PET
plastic. However, Kapton RS offers higher electrical resistance, thin gauge and mechanical properties.
[0065] While heat spreading plate 204 may generally correspond in size to the parts of 20 cooling element 116 which it is attached to, layer 112 may be larger, for example between two millimeters and ten centimeters on either side of either dimension. This enables a significant volume of ice to be formed on layer 112 on the area corresponding to heat spreading plate 204, without connecting to the ice formed on the areas of cooling element 116 which are in direct contact with water.
25 [0066] Fig. 2D shows layer 112, with electrical wires 208 and 218 attached thereto on opposite ends of its coated side. Due to the electrical conductivity of the coating of layer 112, once current is supplied to wires 208 and 218, layer 112 heats, and the ice formed on it releases.
Date Recue/Date Received 2021-02-17

13 [0067] Fig. 3A shows a perspective view of layer 112 with electrical wires 208, 218 and ice cap 304 formed on layer 112 in the areas at which heat spreading plate 204 is in touch with layer 112.
[0068] Fig. 3B is a top view of the cooling unit, with cooling element 116, heat spreading plates 204, layers 112 and ice caps 304 formed on either layer 112.
[0069] It will be appreciated that Figs. 3A and 3B are illustrative, and the ice may be formed on layers 112 and melted in different shapes when current is supplied to electrical wires 208, 218. However, as layers 112 are heated throughout, and due to the size of layers 112 exceeding the projection of cooling element 116, the ice releases and io does not stick to any point or area of cooling unit 116 or hook to the cooling unit 116.
[0070] It will be appreciated that the layers 112 do not have to be heated at once.
However, once any layer 112 is heated, cooling element 116 may not be cooled, in order to save energy. Thus, heating layers 112 at different times causes longer pauses in the ice generation process, therefore in some embodiments layers 112 may be heated concurrently.
[0071] Referring now to Fig. 4, showing a flowchart of a steps in a method for creating and storing cold, in accordance with some embodiments of the disclosure.
[0072] On step 400, a cooling unit may be activated, for example by streaming refrigerant through a cooling element.
[0073] On step 404, which may be performed in an ongoing manner, it may be determined whether a predetermined amount of ice has been created. This check may be performed using any method or any sensor for capturing at least one aspect of the formed ice. In one embodiment, the temperature of the fluid flowing back from the cooling unit may be measured. A temperature below a predetermined value may indicate that at least a sufficient amount of ice has been formed on the cooling unit or members thereof. In other embodiments, the size of the ice block formed on the layers may be determined by analyzing images captured by an image capturing device, or the like.
[0074] It will be appreciated that a cooling system in accordance with the disclosure may further comprise a controllable switch, for closing a circuit such that current is Date Recue/Date Received 2021-02-17

14 applied to the electrical wiring when it is determined that a sufficient amount of ice has been formed on the layer and should be released. The current may be applied for a very short period of time, sufficient for melting enough ice such that the block may release, but not more than that. For example, the current may be supplied for a period such as 10 seconds to five minutes, for example one minute.
[0075] On step 408, if the predetermined amount of ice has been formed, the cooling cycle may be stopped and current may be supplied to electrical wires laid on members of the cooling unit, such as the electrically resistant layer coated by thermally conductive material, such that the Kapton 0 RS layer. The coating is heated, which io causes the ice accumulated thereon to release and float towards the top of the container.
In some embodiments, the heating may start not immediately after cooling has stopped, but at a time difference enabling for temperature balancing. If the amount of ice has not reached the threshold, execution may continue at step 400 and the cooling cycle may continue.
[0076] Once the ice has released, it may be determined on step 412 whether at least a predetermined amount of ice has been stored, e.g., whether the amount of ice that floated to the top of the container is sufficient, or whether there is room for more ice in the container. If the predetermined amount has been stored, the cooling cycle may stop, and the ice may be removed or used, at the current time or at a later time. In some embodiments, a notification may be provided to a user or operator of the cooling system, such as a visual or vocal indication.
[0077] If the amount of stored ice has not reached the predetermined value, execution may continue at step 400 and the cooling cycle may continue. The cooling cycles may continue as long as the rates are cheap, as long as the green energy is available, or the like.
[0078] The formation of an amount for ice that needs to be released, whether the amount has indeed been released, and weather a sufficient amount has been formed within the container may be determined in a plurality of ways. Some embodiments include a visual sensor and a processor for analyzing captured images. Other embodiments comprise the measurement of the height of the content of water and ice within the container. When ice is formed, the water level rises, and when the ice is Date Recue/Date Received 2021-02-17 released, its top floats above the water level, therefore the water level decreases. These changes can be measured, such that the cooling and heating can alternate as required.
When the container is full, the ice cannot float, therefore the water level does not decrease after a heating cycle. Thus, if after a predetermined time, for example twice or 5 three times the expected duration of a cooling and heating cycle there is no change in the water level, it may be assumed that the container is full of ice. In further embodiments, if ice is formed on the cooling element, the temperature of the refrigerant going back from the container is lower than after the ice has been released, therefore the stages of the process may be determined according to the refrigerant temperature.
10 [0079] The flowchart Fig. 4 illustrates the functionality and operation of possible implementations of systems according to various embodiments of the present invention.
In this regard, each block in the flowchart may represent a module, segment, or portion of instructions, which may comprise one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the

15 functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the flowchart illustration, and combinations of blocks in the flowchart illustration, can be implemented by special purpose hardware-based systems such as a controller or Programmable Logic Controller (PLC) that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.
[0080] The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Date Recue/Date Received 2021-02-17

16 [0081] In the description and claims of the application, each of the words "comprise"
"include" and "have", and forms thereof, are not necessarily limited to members in a list with which the words may be associated.
Date Recue/Date Received 2021-02-17

Claims (9)

17What is claimed is:

1. A system for generating and storing cold, comprising:
a storage container for storing cold water and ice; and a cooling unit comprising:
a cooling element positioned within the storage container, wherein cooling refrigerant is streamed within the cooling element;
and an electrically insulating layer having electrically conductive coating, and having electrical wiring laid over the layer, wherein the layer is larger than a projection of the cooling element on the layer along a line perpendicular to the layer, the layer positioned such that the cooling element causes the ice to form on the layer, wherein applying current to the electrical wiring causes the layer to heat, thereby enabling the ice formed on the layer to release and float towards the top of the storage container.

2. The system of Claim 1, wherein the cooling unit further comprises a heat spreading member, the heat spreading member positioned between the cooling element and the layer.

3. The system of Claim 1, further comprising a second electrically insulating layer having an electrically conductive coating, such that the cooling element is positioned between the layer and the second layer.

4. The system of Claim 3, wherein the cooling unit further comprises a second heat spreading member, the second heat spreading member positioned adjacent to the second lay er.

5. The system of Claim 1, wherein the layer is made of an electrically insulating material, and has thickness of at most 200 m.

6. The system of Claim 3, wherein the second layer is made of an electrically insulating material, and has thickness of at most 200µm.

7. The system of Claim 1 wherein the layer has thickness of at most 100iim.

8. The system of Claim 1, further comprising a controllable switch for closing a circuit such that the current is applied to the electrical wiring.

9. The system of Claim 1, further comprising:
a sensor for measuring the temperature of fluid flowing back from the cooling unit or a size of the ice formed on the layer and provide output; and a processor for executing a program for analyzing the output of the sensor and determining a time for applying the current to the electrical wiring.