DE3338009A1 - STORAGE MATERIALS FOR THERMAL ENERGY, METHOD FOR THE PRODUCTION THEREOF AND CONSTRUCTION MATERIALS CONTAINING THEM - Google Patents

Description

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description

The technology of storing thermal energy is ■ important because it saves energy, economic advantages brings with it and enables the appropriate use of periodic energy sources, such as solar energy. Certain storage systems for thermal energy using the specific heat of water, Rock and ceramics are already commercially available.

Systems containing phase change materials will be currently being developed as a high energy storage density accompanies the phase change. The long lasting Thermal energy storage can be achieved through the heat of solution "hydration and reaction of certain chemicals"

Ib can be achieved. All of these thermal energy storage materials result in one or more of the following technical difficulties that must be overcome: Agglomeration, separation of components, supercooling, large volume compared to the thermal capacitance

9.0 did, low thermal conductivity, expensive heat exchange requirements, corrosion of container walls, incompatibility with system components and limited effective surface.

One method of attempting to circumvent these problems has been to construct layered or composite materials the storage materials for thermal energy with concrete or plastic, however new problems of leakage arose, the incompatibility of the components and the reduced thermal conductivity. For example discuss Brookhaven National Laboratory Heport BNL 50827 (August 1977 - February 1978) and BNL 50896 (March 1978 - May 1978) the problems and failures that arise in attempting phase change materials both of the inorganic salt hydrate type, e.g. B. CaClo-6H ~ 0 Na2S0 ^ .10H20) and of the organic type, (e.g. fatty acids, Polyethylene glycol) in common concrete, with polymeric

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to incorporate impregnated concrete and polymer concrete. The project had limited success in attempting phase change materials incorporated into concrete and this minor success was primarily achieved by ' application of foamed glass beads impregnated with CaGIp.6HpO was. The incorporation of storage materials for thermal energy into plastics is described in US Pat 4 00J 426. The storage material for thermal energy is in an uncured polymer resin matrix dispersed, which is then crosslinked. As stated in the patent, this approach is only applicable to storage materials useful for thermal energy that give stable dispersions in the uncured polymer and requires encasing the cured structure in a gas or vapor barrier material for best results to achieve.

Another attempt to overcome the problems has been macroencapsulation. In this case the storage materials for thermal energy of about 2.54 cm (1 inch) diameter or size with multilayer flexible plastic / metal film layer materials or composite materials, Steel cans or polyolefin bottles coated. This experiment can be used for certain purposes be useful, however, the commercial exploitation was dux-ch the poor thermal conductivity, the deformation of the packs and the deterioration of the encapsulation materials hindered by chemical attack and mechanical stresses.

Another attempt is microencapsulation. Investigations thermal energy storage systems containing microencapsulated wax demonstrated the need after encapsulated storage materials for thermi-3g see energy and the technical feasibility of its application. The results proved that microencapsulated

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Storage material for thermal energy can be packed into a bed through which a heat exchange fluid runs. In this way the heat exchange fluid comes into direct contact with the heat storage material. The results also showed improved thermal conductivity, reduced complexity of the heat exchanger, reduced separation problems of the storage materials for thermal energy and reduced equipment costs » However, the total cost of the system turned out to be alc too high for the microencapsulated storage materials for thermal energy of the first generation, due to. the high labor cost of the encapsulation process. These Work is described in the Heport NSF / EAM / SE / AEß 74-09186 of November 1975 ° Later works have these Conclusions not changed significantly "

One of the main goals of microencapsulation was to reduce the path lengths for thermal conductivity in heat transfer systems by reducing the size of the individual thermal energy storage materials used ”. The capsules were manufactured by coating of wax in the 8-2000 m (microns) (0.0003 "- 0.08") area with wall forming materials such as gelatin ₅ (the unsatisfactory generally was), "mod .- · fiziertem nylon? and urea-formaldehyde resin. It was noted that the 50 pm (micron) nylon-coated particles showed no leakage after 300 thermal cycles _s during the 1000-2000 pn (microns) samples some leakage after 150 cycles had. Apart from these Results would be the optimal cost that could be achieved using the prior art microencapsulation techniques three to four times the maximum profitable figure for commercial use, and accordingly this attempt has been dropped until such time as a less costly one Encapsulation process “especially for

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Particles of 8-2000 µm (microns) was invented, or up a method for encapsulating water-soluble salts was found.

Phase change materials (PCM) for application purposes the storage of thermal energy offer compared to other materials such as water or rock, their thermal Storage capacity based solely on sensible heat, advantages. These benefits include a higher one Energy density, a smaller temperature change and than The result is a higher heat collection efficiency. Nonetheless the PCM also have disadvantages. Compared to water or rock, they generally have higher values Costs, bring lower heat transfer rates and are more corrosive PCM phase separation can occur. The widespread use of PCM in thermal storage systems depends on the The cost of effective packaging materials and configurations for the PCM and suitable heat exchange systems.

It is true that each of the experiments discussed earlier offers energy To save a specific answer to the problems of heat storage, however, so far none could be versatile Solution to be found, the one! Flexibility in the choice of materials, a full exploitation of the latent heat, high production efficiency and long-term reliability of the heat storage system made possible. The product according to the invention and the process for producing the product result such a solution-

Another serious problem must be overcome when converting phase change materials into rigid bz \ v ^T. Rigid building materials such as concrete are incorporated, since the problem of expansion of the PClI arises with aen phase changes, which leads to cracks and serious

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Damage to the building material. By the invention Product and the process according to the invention is overcome this otherwise serious problem ..

The invention provides a method for encapsulating both water soluble and insoluble ones Solid state PCM using standard commercially available raw materials and equipment. A feature of the invention includes compressing PCM into tablets the size of aspirin-bζw » Painkillers, which are then coated with organic resin formulations. The size of the resulting Capsules lie between that of plastic balls or plastic spheres and microcapsules. The capsules are small enough to provide sufficient heat transfer and prevent possible phase separation « however, they are large enough for mass production at a low cost. Because the capsules are designed to: They ar · in large quantity for long-term thermal cycle - twists, are durability, flexibility and the cost of the capsule wall materials are important parameters.

In the following the invention is described in more detail = Da;. · Product according to the invention is used as a storage layer product or storage composite product for thermal energy described, which in stiff or rigid building construction components can be incorporated without breaking or hitting or damaging the components or of the product is effected after the product has been subjected to repeated thermal change cycles. This Product contains:

(a) An outer shell or sleeve portion having a longest dimension from about 0.31 cm (1/8 inch) to about 2.54 cm (1 inch) and with internal surfaces that form a Define inner cavity suitable for a

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Include phase change composition for thermal energy storage, wherein the shell consists of at least one seamless or seamless layer of a wall-forming material that is substantially impermeable to and non-reactive with the phase change composition or water, the total volume of wall-forming material about 5 ° / ° forms up to 30 % of the volume of the cavity; and

(b) a phase change composition for storage thermal energy that is permanently located within the cavity of the shell or sleeve, this phase change composition in solid

Ib form, in the form of a molten liquid or in a transition state that is both the liquid as well as the solid form, and the composition is present in such an amount is that the total volume of the composition

2jO in both the solid form and the liquid form or the transition state does not exceed the volume of the cavity.

Preferably the outer shell portion of (a) has convex shaped outer surfaces with rounded edges; the outer shell part of (a) consists of several seamless coatings of the wall-forming material; are the inner surfaces of the shell part (a) coated with a primer substance that is water-resistant and non-reactive with both the phase change composition and the wall forming Material is such as asphalt or an acrylic polymer, and the volume of the primer substance is less than about% of the volume of the cavity.

Preferred wall-forming materials are selected from the groups of copolymer latex of butadiene-acrylonitrile,

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Copolymers of vinylidene chloride-acrylic, resinous latices, Rubber latices, epoxy polymers, polyurethane polymers, Aery! Polymers, cellulose acetate and polyamides.

Preferred phase change materials are a eutectic Glauber's salt mixture, sodium hydroxide, polyethylene, ITodium sulfate decahydrate, sodium thiosulfate pentahydrate, Calcium chloride hexahydrate, magnesium hydrate hexahydrate, the eutectic of magnesium nitrate hexahydrate and ammonium nitrate, Potassium fluoride tetrahydrate, sodium acetate trihydrate, Stearic acid, the eutectic of naphthalene and benzoic acid, and paraffinic hydrocarbons.

Preferably "the liquid density of the phase change composition is at least 85%" but less than 100 % of its solids density when shaped as a compacted powder.

The product can be incorporated into and dispersed in or through rigid or rigid building construction components such as various concrete materials (common concretes, polymers, epoxy or polyester) or plaster, preferably in an amount less than about 75% of the total weight of the final component, preferably 20 to 50% by weight. Such components can All or part of a building wall, floors or ceilings.

It is essential that the volume of the phase change composition in the cavity does not exceed the volume of the cavity at any time, regardless of whether the State of the composition is liquid or solid, or both liquid and solid are in a transitional state includes. If the void volume is exceeded, the product could be damaged by thermal cycles but the most serious problem is

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that - if such a product is incorporated into rigid structural components or building materials - how Ordinary concretes, the building material will break or crack, or other damage, will experience due to the expansion of the product when subjected to thermal cycling.

The preferred method of manufacture according to the invention of the above product is defined as a method of making a phase change memory layer A thermal energy composite product comprising:

(a) the selection of a phase change storage composition for thermal energy with a phase transition temperature within the range of the contemplated environment in which the product will be used should, and keeping the temperature of the composition below the melting point of the composition, after the composition is first melted to provide a solidified phase change composition for thermal energy;

(b) converting the solidified phase change memory composition for thermal energy from (a) into a flowable powder while providing a A flowable powder composition, the composition being at a temperature below its melting point is held;

(c) compacting or compacting and pelletizing or granulating the flowable powder composition of (b) to form individual pellet-shaped or granular compacted powder structures with a longest dimension of about 0.31 cm (1/8 inch) to about 2, 54 cm (1 inch) and a shortest dimension of at least about 0.31 ^cm (1/8 inch) while maintaining the temperature below the melting point of the composition and the degree of compaction

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is controlled to give compacted powder structures with sufficient integrity that one Resist coating formation with a wall-forming material, as well as with an apparent solid density, which is less than or equal to that

Liquid density of the phase change composition; . (d) coating each of the compacted powder compositions with a curable liquid wall-forming material comprising about 5 "to 30% by weight of the Product, based on the final weight of the cured wall-forming material, is where a temperature below the melting point of the composition is maintained and the wall forming Material in the hardened state not reactive with and substantially impervious to both the phase change composition and water is; and subsequently

(e) curing the liquid wall-forming material on each of the compacted powder compositions Formation of a permanent seamless shell or sleeve that is essentially impermeable to and non-reactive with both the phase change composition and water is that of each of the compacted powder compositions encapsulated to provide the product;

whereby the product is suitable for dispersion in rigid building construction components without breaks, Cracks or damage to the components or the product from repeated thermal change cycles of the encapsulated phase change composition for thermal storage purposes.

In step (c) it is essential that the apparent solid density of the compacted powder structures ! Liquid density of the phase change composition

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does not exceed. The apparent solid density of the Structure is the weight of the structure divided by the volume of the structure - measured as if the outer ones Surfaces of the structure would be completely impermeable and impermeable. In practical terms, the compacted Powder structure a mold around which the shell part of the product is poured. The structure therefore defines the cavity within the shell portion of the product. Thus, when melting, the volume of the molten composition does not exceed the volume of the cavity. In addition, is once When the final product is made and the phase change material is allowed to melt, the powder structure never lies again as such.

Another method of making the one according to the invention The product consists in the production of the uncoated structures by agglomeration from the melted Phase change composition “instead of pelletizing the composition of a flowable powder. The best of the process is the same.

Most inert wall-forming materials can be used in the coating steps, including Polymer latices, ceramic mixtures, and polymer systems solvent based. The wall-forming composition described in the others above Techniques used were severely limited in their choices and were only practical Gelatin, nylon and urea types. In some cases polymer walls can occur during the coating procedure be formed by spraying monomer mixtures into the coating forming apparatus or machine. Crosslinking reactions can also occur either during encapsulation or as a treatment step be performed. The wall material is used to

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To keep the shape of the storage material for thermal energy, to prevent agglomeration, migration of the To prevent components from the storage material for thermal energy and to create a specific surface or effective surface for contact with the heat transfer medium to build. It also prevents leaching of the thermal energy storage material. For storage compositions for thermal energy of the special heat and heat fusion type, the wall is designed in such a way that that it prevents penetration of the heat transfer fluid.

In a preferred modification, the capsule walls are made inert, so that the capsules in building materials, such as plastic or concrete, can be potted or stored while providing passive storage without leakage or chemical interaction with the substrate.

j, q An essential feature of the process and the product; - is that the composition is coated with at least one seamless layer of inert wall material in an amount of from about 5 to about JO% by weight of the product. There are preferably at least two layers, but in all cases the layers must be seamless or seamless. Of course, further layers with seams or hems can be present " - provided that at least one and preferably two seamless layers of the wall-forming material are in

3Q of the amount specified above are present.

Among the features and advantages of the invention is the provision of a method of packaging Thermal energy storage materials such that 3g can be used inexpensively in heat exchange systems from direct contact and as additions to

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Plastics, concrete or cement and other building materials. Another feature is providing a protective layer around the typical pill- to marble-sized (the means 1/8 inch to 3/4 of an inch to 1.91 or 2.54 cm or 1 inch) amounts of thermal energy storage materials to protect them from heat transfer fluids or other means to protect. Other features are the prevention of leaching and separation of the storage components for thermal energy, as well as the agglomeration of the storage material for thermal energy. Other Features include greater effective surface area for heat exchange to take place; the provision a process to achieve energetically dense, cost-effective storage systems for thermal energy.

Ib The invention reduces costs, while a method is provided to conserve energy by enabling it to be used appropriately periodic energy sources. Further features and advantages can be found in the present description and the claims evident.

The attached figures are briefly explained below. The figures represent examples of the concept of the methods and products according to the invention. The ffig. 1 shows the method for encapsulating the thermal energy storage material. The ffig. Figure 2 shows an enlarged cross-section of a typical encapsulated thermal energy storage material in accordance with the invention.

The invention is explained in more detail below. A scheme of the manufacturing process is given in the Pig. I. shown. The storage composition 3 for "thermal Energy is put into a chamber 1 for the formation of a coating with various materials for the formation of the invention Product introduced.

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In the case of the storage system for thermal energy it is a material that is in the application temperature range melts and thus absorbs large amounts of heat during the phase of temperature change. Examples

c are sodium sulfate decahydrate, sodium thiosulfate pentahydrate, Calcium chloride hexahydrate, magnesium nitrate hexahydrate, the eutectic of magnesium nitrate hexahydrate and ammonium nitrate, potassium fluoride tetrahydrate, sodium acetate trihydrate, Stearic acid, the eutectic of naphthalene, Q and benzoic acid, and paraffinic hydrocarbons.

Preferred phase change memory compositions are thermal energy sodium sulfate decahydrate, Natriumthiosulf at pentahydrate, calcium chloride hexahydrate, magnesium ^ j- siumnitrat hexahydrate ₇ stearic acid and paraffinic hydrocarbons.

In all cases, the storage composition for thermal Energy can be used by itself or with additives.

r, _n which impart stability or increase performance in various ways. For example, the additives can have effects on the profile of the cooling / heating curve, such as reducing supercooling, they can be used to change the melting point.

2g to suit different purposes, or they can be helpful in binding powder components so that pellets can be formed without crumbing ₇ or they help to establish the relationship between the apparent solid matter density and the liquid density of the composition.

Correct gQ definition. These additions are in the state of Technology known. In all cases, the choice of storage composition depends for thermal energy depends on the temperature at which the system is using the composition should be operated.

If the storage composition for thermal energy is selected, so it becomes pellets under temperature, pressure

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and time conditions pressed by the individual storage material for thermal energy. The size and shape of the pellets depend on the technical Peculiarities of the system. The pellets can be small or large, but a preferred size is between that a typical pill and marble, that is, from about 0.31 cm (1/8 inch) to about 2.54 cm (1 inch). the Shape can be simple or complex, but a preferred shape is shown in FIG. It can - ^ q common commercial pelletizers used like those used today for the manufacture of pharmaceutical pills, for the manufacture of pellets for Nuclear fuel and the like can be used.

With reference to the figures, the thermal energy storage material which has been pressed or compacted into pellets 3 is introduced into the chamber 1. The chamber 1 is a rotating drum with outlet openings 2 and is secured to a motor 4, the j from the base 14 ■. _; q is supported. The motor 4 is suitable for rotating the chamber 1 to move the pellets 3. At the same time, an air blower 7, which can use an air heater 8, directs an air flow 9 into contact with the pellets 3. The exhaust air 10 escapes through the mouth or opening of the chamber 1 and through the openings 2. A spray pump 5 is set up so that it emits different materials 6 for coating the pellets 3. As can be seen from FIG. 1, the rotation of the chamber 1 by the motor 4 and the use of the air blower 7 and / or the spray pump 5 enables various materials to be applied and treated on the pellets 3.

The properties of the encapsulation layer depend on the choice and characteristics of the material being sprayed, the Deposition density and the fixing mechanism. For special storage materials for thermal energy for heat and Heat of fusion are favorable for walls that are impermeable to

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the heat transfer fluid and the storage material for the are thermal energy itself. Thick, strong walls that are crosslinked or post-cured are required can. Examples of wall materials are resinous latices such as Goodrich Geon 576, 652, 2679, 2600X4, 660X1 and 660X2 from Rohm & Haas Rhoplex AC1230, MUI7, MU2 and MUL-. Other examples include rubber latices and epoxy, Polyurethane and acrylic polymers. A balance between the Cost, efficiency and intended

2Q use contribute to the selection of the criteria. In some Cases, more than one material can be beneficial. For example, a first encapsulation layer can be deposited that has a high degree of elasticity, which makes it possible for it to withstand stresses in the memory

_Ί c materials to absorb thermal energy, expansions and contractions. A second outer layer can then be deposited, which is less elastic but more impervious. Numerous processing changes are possible and actually

9n by the nature of the storage composition for thermal energy and the requirements of practical application. For example, pellets with a strong tendency to form flakes, schnitzel bilcunc or crumbling a thick coating with a polymer low molecular weight prior to heavy tumbling treatment in the roll coater.

In a preferred embodiment, the storage device for thermal energy of FIG. 2 is produced using the device shown in FIG. 1. Pellets 3 are loaded into chamber 1. The fan 7, like the motor 4, is put into operation for rotating the pellets 3 in the presence of compressed air 9, which removes fines and dust from the tablets. The heating apparatus 8 is put under Knergie to - if necessary - to dry the pellets at this time from the memory 17 compositions for thermal energy, shown in the

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Fig. 2 with the temperature maintained below the melting point of the phase change composition.

A primer 18 is applied to the composition 17 coated by means of the spray pump 5. This primer 18 serves to seal the core material from other coating materials. Quite often, most of the salts required for storage compositions cause the latent Heat type are used, a coagulation of the over-

2Q latex type pulling materials. The primer should be a Material that is chemically inert with respect to both the core material and the coating. A preferred one Priming material is an asphalt material that has been diluted with a hydrocarbon solvent. Such a-

! 5 primer also improves the adhesion of the coating on the core. Another function of the primer is to indicate the damage to the capsule during the rest of the procedure. Because the primer is often a different color than the core, as is the case with asphalt If so, there will be damage or imperfections of the core indicated by a color change. A single primer coat can be used for various purposes be satisfactory, but it is sometimes necessary or convenient to apply several primer coats up to about 2% by weight, based on the core material 17 to apply. A drying, such as by air or by heated air passing through the fan 8 is circulated is preferred. However, the asphalt or some other primer must be used for the purpose good adhesion can be allowed to be sucked into the surface of the tablet. When the drying stage If done too quickly, the primer can rub off quickly during subsequent processing. If on the other hand If the drying is too slow, the tablets can stick together in large lumps between the primer applications.

After the final coating with primer 18, while it is still wet, a layer of mica 19 or

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Another similar material applied in an amount sufficient to approximate the weight of the product wise to increase about 0.5%. The mica layer 19 serves as a water-resistant barrier and contributes to the Prevent agglomeration of the tablets.

This is followed by a thin layer of a quick drying resin with good adhesion and coverage characteristics as well as applied with good elasticity. This

ig resin 20 can be a latex, such as a butadiene-acrylonitrile copolymer latex, or another similar resin added by the spray pump 5. Satisfactory products can be prepared using such a polymer in the amount of about 3% by weight of the product

- ^ dukts. This layer 2 0 can be applied all at once or by order several very thin layers are deposited. It is essential that the covering or coating formation seamless or without a hem, so that the subsequent Application of the product no binding site or connection

2Q, the successive stresses can be subjected to. The advantage of this highly resilient resin is that it has the relatively fragile primer layer 18 that would otherwise be damaged by abrasion between the tablets when they are in the coating drum be subjected to a tumbler treatment. The acrylonitrile layer cushions the tablet during the Rest of the process and also leads to an additional favorable elasticity of the finished wall.

The main part of the structural wall 21 is then applied and gives structural strength and durability against moisture / vapor transmission. If this wall material has too high a permeability factor, so loses the storage composition for thermal marriage Energy, the phase change material, its hydrate, what the loss of heat storage capacity and the possible Causes damage to the environment of the product. A

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the preferred polymer for this part of the wall is the copolymer of vinylidene chloride-acrylic copolymer. These End wall component is preferably about 15% by weight of the finished product. It is necessary that the wall consists of very thin coatings and between the Application processes or the application is carefully hardened in order to avoid the formation of seams or hems. Suitable curing is indicated by the combination of three factors: surface tack, transparency and shine. Thick coatings resulting from excessive coating application or improper curing can result in the tablets sticking together and subjecting them to tensile stress if they are subjected to tumbler treatment, 5 which leads to bumps and thin spots in the walls. These shortcomings can lead to the tablets soon fail in application. When the coating is applied in a suitable manner, the resulting Wall smooth, glossy and transparent. The curing air should be warmed up slightly periodically to allow the curing process to accelerate. Nevertheless, the temperature should be kept below the temperature at which the core material 17 melts. When the wall 21 is almost complete, can preferably a dust of mica 22 or similar material can be interposed between the latex layers. Through this the resistance to vapor transmission is again improved. The final outer layer 23, preferably of the same composition as the layer 21, and the foregoing outer layer 21 comprise combined about 20% by weight of the finished product. Thinner walls are of course possible and thicker walls can be used if desired. Usually the total amount of the forming the shell part is Wall material at about 5 to about 30 wt .-% of the total product.

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The following examples serve to further illustrate the invention.

example 1

A eutectic mixture of Glauber's salt with a melting point of 22.8 ⁰ C (73 ⁰ F) was formulated as follows: sodium sulfate 17%; Sodium carbonate 20%; Borax 3%; Clay 3%; Water 57%. This mixture was cooled and permeated

^ Q a tablet machine run as a flowable powder and formed into pellets. The pelletized pellets were then coated in asphalt diluted with a hydrocarbon solvent as a primer layer 18, whereupon a layer of mica 19 was added. the

• I suffered from the latex materials described above used to form layers 20, 21 and 23. Layer 20 was molded from butadiene-acrylonitrile latex and layers 21 and 23 of vinylidene chloride-acrylic copolymer. Mica was used again for layer 22

9Π turns. The various layers that make up the Coatings were applied, were without seams or without a seam. These layers were the product of rotation in the drum built up and were of substantially uniform thickness. The amounts of the various coatings and the

2g volumetric relationships were roughly in the middle of the in ranges specified in the preceding description.

The pellets are convex tablets with rounded edges, about 1.27 cm in size (1/2 inch) diameter and about 0.95 cm (3/8 inch) thickness after final coating.

During the tableting stage, the solidification or compacting was controlled in such a way that an apparent Solid density of 1.10 was achieved, the liquid density being Was 1.28.

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Each of the two products was subjected to a performance test by dispersing 30% by weight of the product in a brick made of a conventional concrete mortar mix, of standard dimensions, and then allowed the brick and product to cure for three days. Then the brick 71.1 ⁰ C (160 ⁰ F) was heated and held for several hours at this temperature. Eventually the brick was subjected to various temperature changes that were in a cycle above and below the phase change melting point. No cracks or damage to the brick or product were found.

Example 2

In this example, a thermal energy storage material made of sodium sulfate decahydrate, containing 42% sodium sulfate, 3% borax, 3% clay and 52% water, formulated into a product according to the invention. The ingredients will passed through a colloid mill several times to reduce the particles to micron size and thereby completely remove the salt to hydrate and to form a completely homogeneous suspension of all components. When the weddings are complete is, the phase change material mixture becomes solidified and ground so that it fits through a sieve with a mesh size of 2.38 mm (sieve no. 8). This degree of fineness is favorable for suitable flow characteristics during pelletizing. Solid lubricants, like lithium stearate, can be added in trace amounts

QQ den to improve flow and compression characteristics during pelletizing.

This mass of material is introduced into a tablet press of conventional design. The powder flows from a feed hopper to the pressure or compression chamber, where a batch is sized according to the molds of the machine and is shaped. The standard form of the tablet is

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that of a short cylinder with convex ends. The tablet diameter is about 1.27 cm (1/2 inch) by a thickness of about 0.95 cm (3/8 inch). The compression will controlled so that the tablet has an apparent solid density equal to the liquid density (1.47) of the composition. The solid density of the phase change composition is 1.56.

The various stages of encapsulation described in Example 1 are then carried out in such a way that the finished product has a cross section as in FIG of the accompanying drawings. If the performance is examined as in Example 1, no breaks, cracks or defects in the brick are found.

Example 3

The procedures of Examples 1 and 2 are repeated for each 2Q of the following phase change compositions: Glauber's salt eutectic mixture, sodium hydroxide, polyethylene, Sodium sulfate decahydrate, sodium thiosulfate pentahydrate, Calcium chloride hexahydrate, magnesium hydrate hexahydrate, the eutectic mixture of magnesium nitrate hexa-2g hydrate and ammonium nitrate, potassium fluoride tetrahydrate, Sodium acetate trihydrate, stearic acid, the eutectic of Naphthalene and benzoic acid and paraffinic hydrocarbons.

_"N Each of the pelletized compositions was then encapsulated as in Example. 1

Then each of the above phase change compositions as in Example 1 with the following separate materials for layers 2 0, 21 and 23 (same material for each layer) encapsulated: a copolymer latex of butadiene-acrylonitrile, a copolymer

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of vinylidene chloride acrylic, resinous latices, rubber latices, Epoxy polymers, polyurethane polymers, acrylic polymers, cellulose acetate and polyamides.

These encapsulated products are then subjected to a performance test as in Example 1 and there are no breaks or cracks or damage to the bricks.

Example 4

The above encapsulation structures can also be used in other ways than by compacting the powdered ones PCM chemicals as illustrated in this example are formed. Another method is agglomeration, either in rotating pans, in devices with a fluidized bed or fluidized bed or in devices that have characteristics of these two types. Be in a rotating pan agglomerator

2D seed crystals sprayed with molten material while the pan rotates. The density of the particles can be adjusted by changing the temperature and the droplet size of the sprayed molten phase change composition and the The speed of rotation and the cooling of the pan can be controlled. The structure size is determined by the duration controlled by the cycle and the size of the seed crystals. The structure formed is either spherical or ovoid.

A fluidized bed agglomerator can produce structures for the subsequent encapsulation by similar spraying of molten material onto seed crystals, however in this case the pellets are suspended in a stream of air and behave in the mass as a fluid (i.e. with an angle of repose of zero). A certain particle formation Formation is caused by the collision and adhesion of relatively large particles. As a general rule, they are in a fluidized bed agglomerated particles in the shape of irregular

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and have a lower density than the product of rotating pan agglomerators. The degree of fluidization is a factor of the final density of the shaped particle, this was also indicated for the characteristics of spraying applies in the fluidized bed.

Optimal control of the particle size distribution, shape and density can be achieved with an apparatus which ^{combines the characteristics of both of the above machines} (a manufacturer of such an apparatus is Glatt Air Techniques). The particles are formed in a rotating pan which has a notch or opening on the outer periphery of the pan bottom. This notch allows sufficient air

££ added to fluidize or slightly fluidize the particle bed. .to swirl. The main factors affecting the particle density in this rotary fluidized bed granulator are: the speed of rotation of the pan, the temperature of the fluidizing air, and the amount of PCM supplied. the

r, Q size of the feed notch for the air has a minor Effect on. Through a suitable combination of control factors For example, the density of the formed PCM particle can be controlled so as to be suitable for the performance required density of the finished product

₂ p- is achieved. The rotary fluidized bed granulator described above can also be constructed so that the various coating materials described above are suitably applied, thereby enabling the PCM capsule to be completely manufactured with one apparatus Machine is obtained.

Pellets are made from sodium sulfate hexahydrate (Glauber's salt) formed in a rotary pan type granulator as described above. The PCM is at a temperature just above the melting temperature in a fine Spray applied to form egg-shaped particles

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in the size range from 1.27 to 1.91 cm (1/2 to 3/4 inch) Diameter. The density of the PCM pellets turns out to be slightly less than the 1.47 of the molten PCM, what for the invention is considered essential. The Particles " are then encapsulated as described in Example 1. After a performance test, as in the example 1, no damage to the product or building materials can be determined.

Examples 5 and 6 also demonstrate the critical nature of the density relationship of the phase change structures and densities the phase change composition as such in each of its states.

A similar product was made using calcium chloride hexahyd rat. This material is highly hygroscopic and for this reason measures must ^ _n during pelletizing and encapsulating be taken to prevent the adsorption of water from the air at the surface of the tablets. This surface water would prevent the formation of a coating film or possibly even dissolve the tablet.

Calcium chloride hexahydrate is commercially available, with various stabilizing additives being premixed with it. The tablet formation takes place under conditions in which the relative equilibrium humidity, namely about “Λ 35% / is maintained to reduce the adsorption of water to prevent from airborne.

During the encapsulation step, the asphalt primer coat must be thicker to insure chemical isolation of the salopes from later latex materials, as the salt will coagulate most latices. Therefore, 5% asphalt, based on the total weight of the

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Product, applied. Mica is also added and the remaining layers are then applied as described in Example 1 above.

The apparent solid density of the structure before coating is 1.55 and the liquid density of the phase change composition is 1.35. Thus, when the phase change composition melts, you exceed Volume is the volume of the cavity of the product. The product size is approximately 0.79 cm (5/16 inch) in diameter and 1/4 inch high.

When examining the performance, as in the example 1, the building materials will break when heated for the first time, since the aforementioned density relationships are outside the critical requirements of the invention Product lie.

Example 6

There was prepared a similar product without difficulty using the process according to the invention, as elsewhere running a commercially available paraffin wax having a melting point of 46.7 ° C (116 ⁰ F) used in the but. An addition of 5% stearate was necessary in order to improve the powder flowability and the compaction properties. The tablets were formed as described above. Encapsulation of this material is much easier than that described above

QQ materials. The primer coat made of vinylidene chloride-acrylic copolymer adheres easily to the wax and forms a firm, dense coating. The application of a butadiene-acrylonitrile latex, followed by an additional vinylidene chloride-acrylic copolymer, leads to a finished product as shown in FIG.

The apparent solid density of the compacted structure before coating is 0.87 and the liquid density

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the composition is 0.80. As expected / failed the performance test as in Example 5 above because the volume of the cavity in the sleeve product part was less than the volume of liquid ^- the wax composition.

The above products of Examples 1 to 4, which were produced according to the invention, were evaluated as thermal energy storage products. The products were evaluated during JO various heating cycle studies. These studies demonstrated very successfully that all encapsulated in a suitable manner compositions described above, passed through heat and cold cycles without failure here, so that an industrial property-2g Liehe be life of 20 years or longer accepted for all of these products can. This is in contrast to the evaluation results made on compositions in which the apparent solid densities exceeded the liquid density of the composition PQ, as shown in Examples 5 and 6. Inevitably, these highly compacted products failed during the cycles due to the expansion during the transition from the solid to the liquid phase. Various thermal energy storage products were made in the same way as in Examples 1-4, but during the encapsulation step a seam could be formed in the layers closest to the thermal storage composition. After a certain amount of cycling, the capsules failed with the oQ phase change composition emerging from the capsules at the seams in the capsule.

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Claims (1)

Patent Attorneys · Kuropcan Patent Attorneys' ^: - "W. Abitz ■ ■ "" "Dr-Ir *. D.F. Morf IV. Dipl.-Chcm. M. Gritschneder 3 3 OUU υ Dipl.-Phys. Ahiiz, Morf. Gnuchncder. von Wittgenstein, Postfach 86 01 09, 8000 Munich 86 A. Frhr. from Wittgensteii Dr. Dipl.-CTiem. Postal address / Poslal Address P.O. Box 86 01 09 D-8000 Munich 19.'-October 198. 20 ELH 4 3 PEKKWALT COKKJHATION
Philadelphia, Pa.
V.St.A. Thermal energy storage materials, processes for their production and building materials containing them Claims 1. Storage layer or composite product for thermal Energy suitable for incorporation into rigid building construction materials without a break or a Damage to the materials or the product after repeated thermal treatment of the product cause, characterized in that it contains: a) an outer shell or sleeve part with a longest dimension from about 0.31 cm (i / 8 inches) to about 2.4 cm (1 inch) and with interior surfaces that form an inner cavity which is suitable for a -1- Munich-Bogcnhausen, Poschingcrslraße 6 TclcgKimm: CVieniindus Munich Telephone: (089) 98 32 22 1 ι Ιι χ: 5 21992 (abk / -2- 20 tbsp 4-3 Permanently enclose phase change thermal energy storage composition, the shell consisting of at least one seamless layer of wall-forming material that is substantially impermeable to and non-reactive with the phase change composition or water, the total volume of the wall-forming material is about 5 to 30 % of the volume of the cavity; and b) a phase change storage composition for thermal energy which is permanently disposed within the cavity of the shell, the phase change composition being suitable, in solid form, in molten liquid form or Ib in a transition state, which is both the liquid as well as the solid form includes being and the composition in such an amount that is the total volume of the composition either in the solid form, in the liquid form or in the transition state the volume of the cavity does not exceed. 2. Layered product according to claim 1, in which the shell part of a) consists of a plurality of seamless coverings xi from the wall-forming Material. 3. Layered product according to claim 1, in which the outer Shell part of a) has a convex shaped outer surface with rounded edges. -4-. Layered product according to claim 1, in which the wall-forming The material of a) is a material selected from the group of a copolymer latex of butadiene-acrylonitrile, a copolymer of vinylidene chloride-acrylic, resinous latices, kuut ^ chuklatices, epoxy polymers, Polyurethane polymers, acrylic polymers, Cellulose acetate and polyamides. -2- COPY 1 Q / -, Q q ρ, O fs -5- 20 ELH 45 5> · Layered product according to claim 1, in which the inner
Surfaces of the shell part of a) are coated with a priming substance » 6. The product of claim 5 ₅ in which the primer coating
is a water-resistant primer.;. 7. Product according to claim 6, in which the water-resistant Primer coat consists of asphalt or acrylic polymer 10 8 »Product according to claim 5s, in which the primer coating
in a volumetric amount less than about
5% of the volume of the cavity is present * Ib 9 · Product according to claim 2, in which mica is at least one of the coatings is dispersed that forms the surface of the surface form = 10. Product according to claim 1, in which the thermal energy Euer- phase change composition having a i'lüssigkeitsdichte of b), 85 / ^ _5, however, is at least less than 100% of the composition Peststoffdichte = 11 «. The product of claim 1 wherein the thermal energy phase change composition of b) has a phaser change transition temperature in the range of about
7 ^° C to about 90 ^° C. 12. The product of claim 1, wherein the thermal energy phase change composition of b) is selected from the group of a eutectic mixture
of Glauber's salt, sodium hydroxide, polyethylene, sodium sulfate decahydrate, sodium thiosulfate pentyhydrate, Galcium chloride hexahydrate, magnesium nitrate hexahydrate ₅ the eutectic of magnesium nitrate hexahydrate and
Ammonium nitrate, potassium fluoride tetrahydrate, -3-COPY -4- 20 ELH 4-3 Sodium acetate trihydrate, stearic acid, the eutectic of naphthalene and benzoic acid, and paraffinic hydrocarbons. 13. Construction material component made of concrete or plaster of paris in which less than about 30% by weight of the product of the_claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 dispersed is. 14. Building material according to claim 13> in which the component comprises a wall of a building and the product in an amount in the range of about 20 to 50 wt .-% is available. 15 · Building material according to claim 135, in which the concrete is selected is from the group of concretes, including conventional concrete mixes, polymer concrete, epoxy concrete or Polyester concrete. 16 · Building material component for floors or ceilings in which the product of claims 1, 2, 3s 4, 5 ₅ 6, Ί% 8, 97 10, 11 or 12 is dispersed. 17. Process for the production of a phase change layer or Composite product for storing thermal energy, characterized in that: a) a phase change thermal energy storage composition having a phase change transition temperature in the temperature range of the environment in which the product is to be used and maintaining the temperature of the composition below the melting point of the composition after the Composition was first melted to form a solidified thermal energy phase change composition; b) the solidified phase change Speicner composition for thermal energy from a) in a COPY -5- 20 tbsp 4-5 Flowable powder converts to a flowable one Powder composition "to provide the Maintaining the composition at a temperature below its melting point; c) the flowable powder composition of b) compacted or "compressed and pelletized or" granulated with the formation of individual pellet or granulate-shaped co-compacted powder structures with a longest dimension of about 0.31 ^CE · (1/8 inch) to about 2.54- cm (1 inch) and a shortest dimension of at least about 0.31 ca (1/8 inch) while maintaining the temperature below the melting point of the composition, the degree of solidification being controlled so that solidified powder structures with sufficient integrity to withstand coating formation with a wall-forming material and with a slippable pesticide density that is less than or equal to the liquid density of the phase change composition; d) each of the compacted powder compositions having a curable liquid wall-forming I ^v iaterial coated containing about 5 his 30 wt »-% of the product, based on the weight of the final cured wall-forming material, is =, wherein the temperature below the melting point of the composition held is, and the wall-forming material in the cured state with both the phase change composition and with 3Q water not reactive and essentially for it is impermeable; and subsequently e) the liquid wall-forming material on each the compacted powder composition to form a permanent seamless or seamless shell or sleeve that hardens essentially impervious to and unresponsive to -5-COPY -β- 20 ELH both the phase change composition and Is water encapsulating each of the compacted powder compositions to form the product; whereby the product is suitable for use in rigid construction materials rial components to be dispersed without breaking or damaging the components; or the Repeated thermal change product of the encapsulated phase change thermal memory composition to effect. 18. The method according to claim 17 »characterized in that that in d) several coatings of the liquid wall-forming material are applied. 19. The method according to claim 17, characterized in that in c) the outer surfaces of the structures are convex in shape with rounded edges. 20. The method according to claim 17, characterized in that in d) the wall-forming material is selected is from the group of a copolymer latex of butadiene-acrylonitrile, a copolymer of vinylidene chloride-acrylic, resinous latices, rubber latices, epoxy polymers, polyurethane polymers, acrylic polymers, Cellulose acetate and polyamides. 21. The method according to claim 17, characterized in that in d) the compacted powder structures first be coated with a water-resistant primer. 22. The method according to claim 17, characterized in that in d) the compacted powder structures first be coated with a water-resistant primer, which is selected from the group of Asphalt materials or an acrylic polymer or copolymer material. -7- 20 tbsp 23. The method according to claim 17 »characterized in that that in d) the compacted structures are first coated with a water-resistant primer, which is less than about 5% by weight of the structure. 24. The method according to claim 18, characterized in that mica or similar material on at least stacking one of the coatings of the structure. 10 25. The method according to claim 171, characterized in that that in a) the phase change composition has a liquid density which is at least 85%, but less than 100% of the solids density Composition amounts. 26. The method according to claim 25, characterized in that in a) the composition has a phase change transition temperature in the range of about 7 ° C to 90 ° G. 27. The method according to claim 17 »characterized in that that in a) the phase change composition is selected from the group of a Glauber's salt eutectic Mixture, sodium hydroxide, polyethylene, sodium sulfate decahydrate, sodium thiosulfate pentahydrate, Calcium chloride hexahydrate, magnesium nitrate hexahydrate, the eutectic of magnesium nitrate hexahydrate and ammonium nitrate, potassium fluoride tetrahydrate, Sodium acetate trihydrate, stearic acid, dem Eutectic of naphthalene and benzoic acid and paraffinic hydrocarbons. 28. The method according to claim 17 »characterized in that 3g that in b) a binding material to the flowable powder composition is added to the integrity during the subsequent pelletization in step c) to enhance. -7- -8- 20 ELH 43 29. The method according to claim 17 »characterized in that that in b) fillers are added to the flowable powder composition to create an apparent pesticide to give density after pelletizing in c), which is less than or equal to the liquid density the phase change composition of a). 30. The method according to claim 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29, characterized in that that the encapsulated powder composition product of step e) is then incorporated into a concrete or plaster of paris building material component to form a component with improved thermal mass subjected to repeated thermal treatments without causing damage or breakage to the product or component will. 31. The method according to claim 3O _1, characterized in that the component is a wall of a building and the product is less than about 75 wt .-% of the component. 32. The method according to claim 30, characterized in that that the concrete is selected from the group of conventional concrete mixtures, polymer concrete, epoxy concrete or polyester concrete. 33 · Method according to claim 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 or 29, characterized in that that the encapsulated powder composition product stage e) is then incorporated into a building material component for floors or ceilings. -8th- / ... ■ · ■■■■ -9- 20 ELH 43 34 Process for the production of a phase change layer or composite material product for thermal energy, characterized in that a) a phase change storage composition for thermal energy with a phase change Transition temperature in the temperature range ^ from the Selects the environment in which the product is to be used; b) the composition to prepare a liquid Composition melts; c) the temperature of the liquid composition a temperature just above the melting point of the composition and thereafter Forms individually shaped structures of the composition by agglomerating the composition with agglomerator facilities providing structures with a longest dimension of about 0.31 cm (1/8 inch) to about 2.54 cm (1 inch) and a shortest dimension of at least about 0 »31 cm (1/8 inch), whereupon the temperature of the Maintains structures at a temperature below the melting point of the composition, and agglomeration is controlled with the formation of structures with an apparent density of pests that the I liquid density of the phase change composition does not exceed; d) Coating each of the structures with a curable liquid wall-forming material which is about 5 up to 30% by weight of the product based on the final cured weight of the wall forming Material, keeping the temperature below the melting point of the composition, and the wall-forming material, when cured, is non-reactive with and non-permeable is for both the phase change composition and water, and then —9—
BATH ORIGINAL -10- 20 tbsp 4-3 e) the liquid wall-forming material on each the structures to form a seamless or seamless shell or shell hardens that essentially B is impermeable to and unreactive with both the phase change composition and also water, which is any of the compacted T powder compositions encapsulates to form the product; the product being suitable. in stiff Building material components to be dispersed without breaking or damaging the components or the repeated thermal change product of the encapsulated phase change thermal memory composition to effect. 35 · The method according to claim 34- * characterized in that that in d) several coatings eires liquid wall-forming Materials are applied. 36. The method according to claim 3 ^? characterized, that in c) the outer surfaces of the structures are convexly shaped with rounded corners. 37. The method according to claim 3 ^ j, characterized in that that in d) the wall-forming material is selected from the group of a copolymer latex of butadiene-acrylonitrile, a copolymer of vinylidene chloride-acrylic, resinous latices, rubber latices, Epoxy polymers, polyurethane polymers, acrylic polymers, cellulose acetate and polyamides. 38. The method according to claim 3 ^ -j, characterized in that that in d) the structures are first coated with a water-resistant primer. -10-COPY -11- 20 ELH 45 39- method according to claim 3 ^, characterized in that that in d) the structures are first coated with a water-resistant primer substance from the group of asphalt material and an acrylic polymer or copolymer material * 40. The method according to claim 35, characterized in that that mica is coated on at least one of the coatings of the structure * 4-1 ". Method according to claim 3 ^? characterized in that in a) the phase change composition has a liquid density which is at least 85% of the solids density of the composition « 42. The method according to claim 3 ² H, characterized in that in a) the phase transition composition: is selected from the group of a Glauber's eutectic mixture, sodium hydroxide, polyethylene. Sodium sulfate decahydrate, sodium thiosulfate pentahydrate, Calcium Chloride Hexahydrate, Magnesium Nitrate Hexahydrate5 the eutectic of magnesium nitrate hexahydrate and ammonium nitrate, potassium fluoride tetrahydrate, Sodium acetate trihydrate, stearic acid, the Eutectic of naphthalene and benzoic acid and paraffinic hydrocarbons. 43- The method according to claim 3 ^ _5, characterized in that in c) the agglomeration devices are selected from the group of agglomeration devices consisting of a rotating pan agglomerator ₅ a fluidized bed or. fluidized bed agglomerator or a combination of a rotating pan and fluidized bed or »fluidized bed agglomerator -11-COPY ' ^Λ »« «NnmiMAI -12- 20 ELH 43 44. The method according to claim 34, 35, 36, 37, 38, 39, 40, 41, 42 or 43, characterized in that the encapsulated structure of step e) is then incorporated into a concrete or plaster of paris building material component to form a component of improved thermal mass which can withstand repeated thermal treatments without damage or breakage of the product or component.
10 45. The method according to claim 44, characterized in that that the component is the wall of a building and the product is less than about 50% by weight of the component amounts to. 46. The method according to claim 34, 35, 36, 37, 38, 39, 40, 41, 42 or 43, characterized in that the encapsulated structure of the product of step e) subsequently is incorporated into a building material component for floors or ceilings. -12- COPY