The invention relates to a tube freeze exchanger, particularly for feeding a chill accumulator. The apparatus according to the invention makes it possible to extract freeze energy and store it in ice.

From American patent application US4334412 (A) there is known a cooling system particularly suitable for use in the air-conditioning of buildings. The system includes: (A) A cooling zone containing a conduit for cooling fluid, the conduit encountering the heat load, means in the conduit for propelling the fluid through the conduit, and cooling fluid in the conduit; (B) A refrigeration zone containing a closed refrigeration circuit for refrigerant, chiller means in the circuit for extracting energy from the refrigerant, means for circulating refrigerant in the circuit and refrigerant in the circuit; and (C) Collection means connected to the refrigeration zone for removing energy extracted by the chiller. The cooling and refrigeration zones are connectable through a heat exchanger for transfer of energy between the fluid and the refrigerant and the refrigerant comprises a slurry of ice and water which may be partly stored in a reservoir constituting part of the refrigeration zone. In this system, a reserve cooling capacity can be stored in the reservoir for use during cyclic requirements therefor.

From an American patent application US5139549 A there is also known an apparatus and method for cooling using aqueous ice slurry fed by a conduit from a freeze exchanger directly to one or more heat exchangers for cooling or air conditioning one or more defined spaces. Warm water withdrawn from the heat exchangers is returned, with or without prior cooling, to the freeze exchanger to be converted into aqueous ice slurry. Warm water from the heat exchangers may be fed to a central thermal energy storage tank containing a bed of ice to form aqueous ice slurry. When heat exchangers have coiis too small for an aqueous ice slurry to flow through, the slurry is mixed with warm water from the heat exchangers to melt the ice and produce cold water which can be passed through the heat exchangers.

American patent application US6793007 Bl discloses a cooling system for an apparatus powered by electricity, that generates a substantial amount of heat during operation, and the heat must be dissipated to avoid failure of electrical components, such as semiconductor devices and integrated circuits, comprising the electrical apparatus. The cooling system employs liquid ice impinged on a heat sink thermally coupled with electrical apparatus. The attendant phase changes of the liquid Ice first to water and then to steam to remove a substantial amount of waste heat to prevent failure of the electrical apparatus.

Whereas American patent application US4509344 (A) discloses an apparatus comprising a freeze exchanger having an aqueous liquid feed stream inlet and an aqueous liquid stream outlet; a closed loop refrigeration system for supplying a refrigerant to the freeze exchanger for indirectly cooling aqueous liquid fed thereto; an ice storage tank; a conduit for withdrawing aqueous liquid, or a mixture of ice and aqueous liquid, from the freeze exchanger outlet and delivering it to the ice storage tank; a conduit for removing cold aqueous liquid from the ice storage tank and feeding it to a heat exchanger to cool fluid used for cooling purposes; and a conduit for removing warm aqueous liquid from the heat exchanger and feeding it to the ice storage tank, or to the freeze exchanger, or partially to both.

American patent application US4735641 discloses an invention related to producing ice. Ice is produced by supplying a cold antifreeze solution into a freezer vessel evacuated to operate at the triple point of water; feeding a stream of water into the vessel whereby part of the water flashes into water vapor which extracts its latent heat of vaporization from the water in the freezer and part of the water is cooled and converted to ice crystals in a pool of water therein and the water vapor is condensed by and absorbed into the cold antifreeze solution thereby forming a more dilute antifreeze solution; removing a mixture of ice crystals and water from the vessel; withdrawing dilute antifreeze solution from the vessel and subjecting the solution to a water separating treatment to separate water and form concentrated antifreeze, combining the concentrated antifreeze with antifreeze solution withdrawn from the vessel to form a combined antifreeze stream; cooling the combined antifreeze stream to produce a cold antifreeze stream; and recycling the cold antifreeze stream to the freezer vessel.

American patent application US2007056313 Al relates to an apparatus for producing sterile ice slurries for medical cooling applications. The apparatus is capable of producing highly loaded slurries suitable for delivery to targeted internal organs of a patient through medical size diameter tubing. The ice slurry production apparatus includes a slurry production reservoir adapted to contain a volume of a saline solution. A flexible membrane crystallization surface is provided within the slurry production reservoir. The crystallization surface is provided in a tank. A deflector in the form of a reciprocating member is provided for periodically distorting the crystallization surface and dislodging the ice particles which form on the crystallization surface. Using reservoir mixing the slurry is conditioned for easy pumping directly out of the production reservoir via medical tubing or delivery through other means such as squeeze bottles, squeeze bags or syringes.

Published patent application DE19936523 Al describes a cooling system including a refrigerator with an evaporator, a compressor and an expansion element, an evaporator and a cooling point supplied with ice slurry from an ice slurry reservoir, with part of the fluid at the cooling point supplied back to the ice slurry reservoir, via a return tine and a heat exchanger.

From an international patent application WO 2015/099547 there is known a feed coliector, particularly for a multiple source heat pump which has a water filled body having the form of a reservoir, whose top cap end in the form of a reverse funnel inserted into an ice slurry reservoir located thereover is provided with an ice- breaking pump on the top, said pump having a discharge conduit with an outlet going into an ice slurry reservoir , which has a pump for removal of accumulating ice, and in the body of the collector, below the water bath level there is at least one heat exchanger, which has the form of a flat chamber filled with a refrigerant medium, enclosed, provided with a pipe and a stub pipe ( with a cut-off valve ), said chamber having deformable walls, which can deform to at least a small extent when exposed to internal pressure in the chamber of the heat exchanger , wherein there is an evaporator in the chamber of the heat exchanger, said evaporator favorably having a form of a ribbed coil pipe in Tichelman arrangement, a meander arrangement or a worm arrangement, said coil provided with a radiator fed with compressed gas from the compressor of a heat pump. The evaporator is enclosed by a hollow flexible frame which on both sides of its circumference has plates which are firmly attached to it, said plates forming deformable side walls made of metal or plastic. The heat exchanger is a hollow flexible frame, which on both sides of its circumference has plates which are firmly attached to it, said plates forming deformable side walls and made of metal or plastic and provided with a vibrator.

The collector has a mixing water pump provided with an injector for aeration. The deicing system comprises an ice-breaking pump connected on the one side to a suction float, and on the other side to an outlet pipeline closed with a floating ball non-return valve installed in an internal ice storage container,

Chill accumulators known from the art which use tube exchangers for accumulating freeze energy store it in such a way that ice gradually builds up on them during their operation. This process reduces the active surface of the exchanger and in consequence compromises its operating parameters until it loses its capacity to accumulate energy. Existing installations are provided with tube exchangers of a considerable length which delays the process of the total build-up of ice. This increases the amount of cooling medium in the exchanger installation and in consequence the flow is too slow. Due to the cost of building tube freeze exchangers known from the art, materials with low heat conductivity are used, mainly polyolefine tubes.

Tube freeze exchanger according to the invention comprises an external tank filled with slurry of ice and water with at least one tubular portion submerged therein, preferably with a developed internal surface, provided with elements placed in its inside (obstacles) which force turbulent flow of the cooling medium, and on the outside provided with longitudinal radiators in form of at least two longitudinal fins made of metal or plastic placed opposite to each other, mounted on a tube in longitudinal guides formed by at least two external covers put together forming a shield of a tubular portion with a circle or polygon-shaped cross-section, preferably a diamond with a longer vertical diagonal line, and installed together with a tube on both sides in freeze energy conducting connecting blocks, provided with pipe connections, at least one side of each tubular portion enclosed with external covers there are perforated aeration conduits.

Preferably, the element forcing turbulent flow of the cooling medium is a fixed worm arrangement in form of a section of helically twisted strip or section made of metal or plastic and mounted longitudinally inside the tubular portion. In another preferred embodiment of the invention, the element forcing the turbulent flow of the cooling medium is a worm arrangement having a form of a cylinder segment with a convex section wound and fixed to its surface along the screw line e.g. a bar, wire or a thin conduit, placed inside the tubular portion.

Elements forcing the turbulent flow of the cooling medium in the tubular portion and a built-in fin radiator with shields on a pipe form a system maintaining a relatively constant freeze exchange along the entire length of the tubular portion.

In a preferred embodiment of the exchanger according to the invention such a system is formed by a worm arrangement installed inside the tubular portion in form of a cylinder with diameter decreasing along the length of the tubular portion, and the surface of the external radiator fins increasing along the length of the tubular portion.

Tube freeze exchanger according to the invention in a preferred embodiment of the invention comprises several tubular portions connected in series or in parallel or in Tiche!man arrangement in horizontal or vertical rows.

In a preferred embodiment of the exchanger according to the invention comprising several tubular portions connected in parallel in horizontal or vertical rows supplied with a gas cooling medium to better distribute the cooling medium in the exchanger tubes, the inlet and outlet of the connected tubes of exchangers is provided with an internal chamber in form of a tube with cone-shaped openings along the entire length thereof which have the function of nozzles and are provided along the entire length thereof. Cooling medium is supplied to the exchanger through an internal inlet chamber, nozzles through a connection pipe to tubular portions of the exchangers. The cooling medium is extracted from tubular portions of the exchanger through the connection pipe and outlet nozzles to the outlet chamber.

To reduce the outflow of ice and the accumulation of the entire volume thereof in the upper part of the tank, under the horizontal rows of tubular portions there are horizontal openwork dividers in form of mesh sheets which stop the separated ice between horizontal rows of the tubular portions of the exchanger.

Tubular portions may, in a special embodiment of the invention, be connected through insulating connecting blocks made of material that poorly conducts freeze energy, cylinder-shaped, or preferably a polyhedron cut on one side towards the inside and equipped with pipe connectors seated therein. It is preferred when the connecting blocks are made of a mixture comprising chemically- cured synthetic resin and a heat-insulating filler.

To accelerate uniform crystallization of water in the entire tank of the exchanger, the water filling the tank includes an addition of heterophasic crystallization nuclei, preferably an addition of microcrystaliine silica or microcrystalline aluminium oxide in the amount of 2-3% by weight per the weight of water in the exchanger's tank. The external tank and tubular portions of the tube exchanger according to the invention are made of metal or plastic.

The tube exchanger according to the invention uses liquid or gas as the cooling fluid.

The system comprising internal and external elements which maintain a relatively stable freeze exchange along the entire length of the tubular portion comprises elements placed inside the tubular portion which control the active cross-section of the turbulent flow of the cooling medium and elements which extract freeze energy in the form of the walls of a tubular portion with developed internal surface and a radiator whose fins may have sections of varying width, makes it possible to control the flow volume of the cooling fluid and the active surface of the exchanger which leads to uniform build-up of ice along its entire length.

To maintain a relatively steady freeze exchange at the inlet of a tubular portion where the cooling medium has the lowest temperature, the active cross- section of the tubular portion is the smallest as a result of using a liner of the biggest cross-section, also the size of the area of exchange of energy from water - determined by the width of the radiator fins - is the smallest i.e. the width of the fins is the smallest. The temperature of the cooling medium increases along the length of the tubular portion and in consequence its flow speed decreases by gradual reduction of the cross-sectional area of the liner and increase of the width of radiator fins. The slowdown of the flow increases extraction of energy in this section of the exchanger. Obstacles on the surface of the liner placed in the tubular portion, attached for example in the axial screw line ensure turbulent flow of the cooling medium along the entire length of the tubular portion which results in the most efficient freeze exchange. Such a system for controlling the extraction of the freeze energy stream, ensures even build-up of ice along the entire length of tubular portions.

To remove ice from the surface of exchanger tubular portions an agent with higher temperature is introduced temporarily thus reversing the direction in which the cooling medium circulates in the compressor with its energy quickly transferred to the external layer of the tubular portion which leads to separation of ice pieces. The separated pieces of ice, thanks to radiator fins, have a limited and a relatively small size. The separation of ice pieces is accelerated by air streams coming from aeration conduits running along tubular portions. Air streams disperse the separated ice and accelerate the upwards movement of ice pieces, their movement restricted by mesh nets placed over rows of tubular portions under which concentrated ice slurry accumulates. This phenomenon is intensified by the use of external shields of tubular portions, particularly with a diamond-shaped cross- section which hinder the occurrence of dead zones where freeze exchange is difficult.

A considerable surface of ice separated from tubular portions chills water in the exchanger tank and enhances the creation of new slurry of ice and water crystallization environment - thanks to crystallization nuclei present in water. Tube freeze exchanger according to the invention makes it possible to achieve high efficiency impossible to obtain for other designs of freeze exchangers known from the art, and at the same time reduce the electric energy consumed during the operation of the exchanger. The effect is obtained thanks to the exchanger de-icing system, increase of the active surface with the surface of separated ice and its dispersion between rows of exchangers which chill water in the tank. A direct positive effect on the efficiency of the tube freeze exchanger according to the invention is obtained thanks to the system enhancing the creation of ice nuclei, control of the cooling medium flow by means of internal obstacles, a forced turbulent flow, exchanger power control along the entire length thereof through the possibility of replacing radiator fins and adjusting their area to working conditions, as well as a system of stable supply of the cooling medium to tubular portions of the exchanger through inlet and outlet chambers with nozzles. The energy of the cooling medium flowing turbulently through the exchanger comprises thermal and kinetic energy. Parameters, particularly pressure and temperature are also split between two components of energy into static and dynamic parameters. The construction of the exchanger optimizes all the parameters of the cooling medium referred to thus saving electric energy consumed by the compressor and required to produce ice.

While aerating the tank based on the traditional construction of the exchanger known from the art, exchanger tubes installed vertically one over the other create dead zones without water flow. The construction of the tube freeze exchanger makes it possible to obtain a bigger active area of exchange and an increased efficiency of energy extraction. The efficiency of the process of producing ice in conditions provided by the tube exchanger according to the invention, with a longitudinal fin radiator, is higher than the efficiency obtained by installations known from the art. Experimental research performed for installations of comparable power shows the increase of the coefficient of performance by at least 20% against traditional apparatus known from the art. The increase of efficiency contributes to spectacular energy savings during the accumulation of the freeze energy.

The tube exchanger according to the invention is to convert energy and store the freeze energy in the shortest possible time and with the best parameters related to savings on electric energy used for supplying the compressor. The key performance effect directly impacting its efficiency is the operation of the exchanger on the entire surface thereof resulting in even build-up of ice, and the best possible supply parameters.

The exchanger according to the invention in one of the embodiments comprises a set of tubular portions, each of which being a single exchanger, connected in Tichelmann arrangement and submerged in a water tank. Tubular portions may be connected to form sets by means of separable connectors, in series and in parallel, thus changing the exchanger's operating parameters, which facilitates the control of the entire exchanger system. in a particular embodiment of the exchanger according to the invention, wherein the cooling fluid is gas cooling medium, the tubular portions connected in parallel arrangement, the inlet and outlet of connected tubular portions of the exchanger according to the invention is provided with an internal chamber in form of a tube with openings - nozzles, along its entire length.

Gas cooling medium is supplied to the exchanger through an internal inlet chamber, inlet nozzles through the connecting pipe to the exchanger tubes. Cooling medium is extracted from exchanger tubular portions through the connecting pipe and outlet nozzles to the outlet chamber. The inlet and outlet in form of a tube with nozzles ensures uniform supply and removal of the cooling medium from all tubular portions of the exchanger. Such a construction is particularly useful when the direction of the flow of the cooling medium is changed during the cooling and de- icing of the exchanger tubular portions. The phase transition of the cooling medium in the exchanger, from liquid to gas and the other way round - when the flow direction is changed, requires particularly precise distribution of the cooling medium to all tubular portions of the exchanger. This condition is met by varying diameters of the inlet and the outlet chambers, as well as varying diameters and spacing of nozzles installed. Such a construction makes it possible to control the flow and to evenly distribute the cooling medium in all tubular portions of the exchanger, regardless of the direction of the flow and the state of aggregation of the cooling medium, meaning gas, during the heating of the exchanger or liquid - during the cooling operation. Exchanger operating parameters i.e. diametrically different pressure of the gas cooling medium at the heating stage {approx. 15 bars), and the cooling stage (approx. 3 bars), require the chambers and inlet and outlet nozzles to have different sizes and thus different efficiency. The use of two doubled chambers in the construction of the exchanger at the heating stage - inlet chamber and outlet chamber, as well as for the cooling stage - inlet chamber and outlet chamber, offers the possibility to control in an optimum way the flow of the cooling medium through the exchanger in each working mode. Uniform supply of the cooling medium to the tubular portions of the exchanger according to the invention results in an even build-up of ice and quick de-icing of the exchanger which makes it possible to obtain high efficiency of the apparatus both during the build-up of ice and the de-icing stage.

The cooling medium extracts energy through the internal wall of the exchanger. The fin radiator extracts energy in the process of chilling water in the tank and during the phase transition to ice. Ice builds up on the exchanger.

If an arrangement of exchangers according to the invention is made, the operation of a section of exchangers may be cyclically changed from being supplied with chilled cooling medium to being supplied with heated cooling medium and the other way round.

The supply of chilled cooling medium results in the build-up of ice on the exchangers, while warm medium is to facilitate the regeneration of an exchanger and removal of the ice on the surface of tubular portions. Energy for the regeneration of the exchanger is supplied by reversing the flow of the cooling medium in the compressor. The heating up of a thin layer of ice covering a tubular portion of the exchanger facilitates spontaneous separation of ice. The fins of the exchanger's radiator prevent the build-up of ice on the exchanger tube in the full circumference by dividing the ice formed into two halves, Radiators increase the active surface of the exchanger. Fins of the exchanger radiator contact water on a much larger surface than it is the case with the exchanger tube. Water temperature above zero supplies more energy than the contact point with the tubular portion of the exchanger. As a result of this kind of construction the fins of the exchanger radiator get covered with ice only within a small distance from the surface of a tubular portion and during the regeneration extract energy directly from water thus enhancing the removal of ice.

Connecting blocks poorly conducting freeze energy used for connecting individual tubular portions prevent the build-up of ice on tubular portions in connection zones due to their thermal properties.

On both sides of exchanger tubular portions between fins there are aeration conduits with openings for aerating both sides of the exchanger. The compressor supplying air to air pipes is activated during the regeneration of the exchanger. Once the layer of ice covering the exchanger tube melts, air is pumped in between the tube and ice thus enhancing the separation of ice. Water displacement makes the separated ice come up to the surface.

The exchanger is divided horizontally into sections by means of meshes. The meshes are used for trapping the ice flowing out of individual tubes of the exchanger after the regeneration and facilitate free flow of water between pieces of separated ice while the ice is trapped in sections, also close to the bottom, and chills the water accumulated therein. This chilling process eliminates the phenomenon of reverse thermal stratification as a result of which the temperature of water at the bottom of the tank is maintained at +4 °C which does not enhance the build-up of ice, including in the bottom zone of the exchanger. The increasing amount of ice and its active surface, following each de-icing of the exchanger, extracts energy from the surrounding water and enhances the process of ice-buildup.

The ice trapped in exchanger sections under the meshes also ensures even discharge of accumulated energy and makes it possible to obtain a favorable supply of the installation extracting the freeze energy.

The aeration system installed under the exchanger causes water movement, the water flowing around the side walls of exchangers enhances the extraction and supply of energy. At the same time the movement of water eliminates the settling of crystallization nuclei in the bottom zone and distributes them throughout the tank.

The construction of the exchanger according to the invention eliminates the dead zone around which the water does not flow during the aeration process in the iced tubes, and the streamlined shape of tubular portions provided with fin radiators enhances its efficiency. The subject of the invention is presented in its embodiments on the attached drawing where:

Fig. 1 shows a longitudinal vertical section of the tube freeze exchanger,

Fig. 2 shows a single tubular portion a) side view, b) top view,

Fig. 3 shows a cross-section of a tubular portion of the exchanger provided with a simple helical worm arrangement in form of a twisted band,

Fig. 4 shows a longitudinal axial cross-section of a tubular section of the exchanger provided with a simple helical worm arrangement in form of a twisted band,

Fig. 5 shows a cross-sectional view of a tubular portion of the exchanger provided with a cylindrical worm arrangement with a gradually decreasing diameter, provided with an obstacle helically-wound on its surface, and a radiator with the height of fins increasing zonaily,

Fig. 6 shows a longitudinal axial section of a tubular portion of the exchanger provided with a cylindrical worm arrangement with a gradually decreasing diameter, provided with an obstacle helically-wound on its surface, and a radiator with the height of fins increasing zonaily,

Fig. 7 shows the vertical cross-section of the tube freeze exchanger comprising a multi-level multi-section set of tubular portions including a bottom aeration system, placed in a tank.

Fig. 8 shows a) longitudinal section of the tube exchanger with its tubular portions connected with inlet and outlet chambers with nozzles supplying the exchanger with gas cooling medium, b) section of the connecting pipe, position a-a, c) section of the connecting pipe, position b-b,.

Fig. 9 shows a cross-section of an embodiment of a tubular portion of the exchanger, octagonal in cross-section.

Fig. 10 shows the exploded view of elements of an embodiment of a tubular portion of an exchanger, octagonal in cross - section.

Fig. 11 shows a cross-section of an embodiment of a tubular portion of the exchanger, square in cross-section.

Fig. 12 shows an exploded view of elements of an embodiment of a tubular portion of the exchanger, square in cross-section.

The exchanger according to the invention has a water tank ijnade of plastic wherein sets of interconnected single loops formed by tubular portions 2 are installed in horizontal rows, the supply and return of the cooling medium provided on the same side of the exchanger. Such a construction offers the possibility of easy and fast replacement of tubular portions 2 of the exchanger single loops twisted with separable connectors 3. A single tubular portion 2 of the exchanger is made of a metal tube with corrugated inside and is provided on the outside with longitudinal radiators in form of at least two longitudinal fins 4 placed vertically and opposite to each other, comprising a metal handle and a flat insulation element made of plastic 16 placed therein, mounted on the tubular portion 2 in longitudinal slotted guides formed on the contact line of at least two external covers 5 put together forming an external divisible shield of the tubular portion 2 with a diamond-like shaped cross-section with a longer vertical diagonal. Tubular portions 2 of the exchanger are mounted together with covers 5_and fins 4 of the radiator on both sides in insulation connecting blocks 6, provided with pipe connections. On both sides of each tubular portion 2_encased with external covers 5 and enclosed with a lock 15 there are perforated aeration conduits 7. Inside each tubular portion there is attached a longitudinal element forcing turbulent flow of the cooling medium being a worm arrangement in form of a cylinder 8 placed inside the tubular portion, with diameter decreasing gradually along the length of the tubular portion 2^ a convex obstacle 9 in form of a thin conduit wound on the surface of each of the cylinder sections varying in diameter and soldered along the screw line. To maintain steady exchange of freeze energy along the entire length of each tubular portion comprising a worm arrangement in form of a cylinder with a gradually changing diameter, the surface of fins 4 of the external radiator also gradually increases along the length of the tubular section 2.

In another embodiment of the exchanger according to the invention, the element forcing the turbulent flow of the cooling medium is a helically twisted strip 10 made of metal or a plastic plate, installed inside a tubular portion.

In the exchanger according to the invention, the tank ljs divided into horizontal sections separated with horizontal mesh sheets 11, ice separated from the surface of tubular conduits is accumulated thereunder.

To prevent the build-up of ice on tubular portions 2 in the end zones adjacent to connectors 3, tubular portions 2 are connected to each other through insulation connecting blocks 6 made of a material poorly conducting freeze energy, polyhedron-shaped, cut on one side towards the inside at an angle greater than 30 degrees with pipe connectors seated therein.

To ensure uniform formation of ice crystals with slight variations in size in the entire volume of the slurry of ice and water filling the tank 1, the slurry of ice and water filling the tank of the exchanger contains an addition of heterophasic crystallization nuclei in form of microcrystall ^' tne silica in the amount of 2-3% by weight per the weight of slurry in the tank 1 of the exchanger.

In the bottom part of the tank 1 there is a set of perforated bottom aeration conduits 12. Air bubbles produced by this set improve freeze exchange in the entire tank 1 of the exchanger, and enhance the separation and removal of ice layers formed on the surface of individual tubular portions 2.

During the operation of the exchanger, the coldest cooling medium flowing into a tubular portion 2, slows down and warms up as it flows therethrough. Change of diameters and the length of worm arrangements, as well as the size of radiator fins facilitates effective control over the heat extraction process so that it is uniform along the entire length of the exchanger and results in a build-up of an even ice cover over its entire surface. A limitation to the use of this control is the minimum turbulent flow in each tubular portion of the exchanger.

In a preferred embodiment of the exchanger according to the invention with the cooling fluid being a gas cooling medium, tubular portions of the exchanger were connected in parallel, in pipes connecting 17 tubular portions of the exchanger, from the inlet side and from the side with the cooling medium outlet, there are two chambers mounted on each side 13: inlet and outlet, in form of a tube with nozzles 14 and cone-shaped openings.

The exchanger according to the invention is intended particularly for supplying chill accumulators.