Method for releasing latently stored heat and apparatus for carrying out the method

Abstract

The invention relates to a method for releasing latently stored heat and a device for carrying out the method. Chemical heat storage systems are often irreversible, while purely physical heat storage systems release heat with a delay and unevenly during cooling processes. The objective is to overcome these disadvantages. This is achieved with a method in which heat is stored in a stable emulsion during its formation. Subsequent disruption of the emulsion leads to reliable phase separation, releasing the previously stored heat. For the first time, a physicochemical system can thus release and provide heat on demand, analogous to a heat pump, without relying on the complex and vulnerable components of a heat pump. The most cost-effective and established systems from the field of oil-based heat exchangers and coolers can be used.For the first time, a compact and localized addition to energy management systems is now possible. A corresponding device, requiring only 1 to 2 cubic meters of space, can effectively feed thermal energy into a water-based heating circuit in a single-family home.

Description

SCIENTIFIC AREA

[0001] The invention is situated in the field of heat and energy management. While in the early 2000s discussions in this area focused primarily on insulation measures, holistic concepts are now increasingly gaining ground. These concepts consider people and their accompanying civilizational components as a whole, aiming to develop them as efficiently as possible into a system that does not burden the environment, or at least minimizes its impact. The FlexQuartier project at the Technical University of Central Hesse serves as an example (MSc Felix Holy, 2021-11-16, 'The Hybrid Storage System in the FlexQuartier', project presentation focusing on high-temperature storage). GENERAL BACKGROUND

[0002] The present invention relates to a method for releasing latently stored heat according to the preamble of the independent claims.

[0003] 'Latent stored heat' refers to physically and / or chemically releaseable heat that is contained in a system and can be accessed.

[0004] US patent 1 565 510 A discloses an 'exothermic heater' in which a chemical reaction is used to heat water: In a shielded housing, water vapor is generated, which can be used to fix a permanent wave.

[0005] US Patent 2 004 076 discloses an insulated oil boiler which can be heated via a metallic heating element; at a temperature specific to the respective oil mixture, an irreversible decomposition and / or reaction process is triggered, which causes the oil temperature to rise rapidly.

[0006] From GB 1 092 412 A a device is known in which an oil serves as part of a two-circuit oil-water heat cycle as a heat storage and heat reserve, via which water can be heated as needed and fed into an established heating circuit.

[0007] In DD 252 664 A1, it is additionally proposed that heat storage systems – possibly with additional heat-storing processes such as mass or phase transformations – be designed to be mobile and transported to the respective location of need after charging. For the purposes of this description, quantities of heat that are metastably contained in a system and can be released by targeted measures such as temperature changes, the addition of an activator, or the addition of a catalyst are referred to as latent heat. DESCRIPTION OF THE STATE OF THE TECHNOLOGY

[0008] Typical processes are based on a heat-containing oil that serves as a heat source.

[0009] From DE 31 26 534 A1, a multi-circuit device comprising an oil circuit and a water circuit is known, in which oil is heated as part of an engine cooling system and can be used to heat the driver's living area via a water circuit connected by a heat exchanger. In this way, heat from a chemical process – in this case, the combustion of fuel in the engine – is extracted from the oil.

[0010] A disadvantage of these types of systems is that heat is generated in an irreversible process. Integrating irreversible processes into a comprehensive energy management system is difficult from an ecological perspective: Irreversible processes always produce emissions and waste of an energetic and chemical nature.

[0011] The object of the present invention was therefore to overcome the disadvantages of the prior art and to provide a reversible mechanism which is able to provide a meaningful and environmentally less burdensome addition to a holistic energy management system.

[0012] This problem is solved according to the features of the independent claims. Advantageous embodiments are described in the dependent claims and the following description. SUMMARY OF THE INVENTION

[0013] According to the invention, a method for releasing latently stored heat comprises the steps a1) Mixing a solid heat storage material with low and / or high melting and / or boiling materials; b1) Supplying heat and melting the heat storage material until an emulsion with latently stored heat is obtained; c1) Breaking the emulsion by driving off low-boiling components into a gas phase part, leaving a remaining, liquid, broken emulsion part and c2) Extracting the latently stored heat from the broken emulsion part which forms solid heat storage material particles while releasing heat, while maintaining a dispersion. DESCRIPTION OF THE INVENTION AND ADVANTAGEOUS FEATURES

[0014] According to the invention, the method for releasing latently stored heat comprises several steps. In step a1), a solid heat storage material is first mixed with materials with low and / or high melting and / or boiling points. Preferably, at least one paraffin-based heat storage material is used; the other components can be selected from the widely and inexpensively available saturated and unsaturated hydrocarbons; a completely biogenic mixture of renewable raw materials is particularly preferred. In step b1), heat is supplied until the melting of the heat storage material is complete; optional homogenization of the liquid phases with mechanical and / or energy-injecting systems such as stirrers, cavitation shear mixers, ultrasonic and / or high-pressure homogenizers can advantageously shorten the time required to obtain an emulsion with latently stored heat.Heat is particularly preferred from at least one natural heat reservoir, including geothermal heat, solar thermal heat, waste heat from industrial processes, waste heat from households, waste heat from generators, heat from passive heat storage systems, waste heat from data centers, heat from high-temperature storage systems, and heat from central heat storage systems.

[0015] In step c1), the emulsion is broken down by expelling low-boiling components into a gas phase, leaving a remaining liquid, broken emulsion portion. Preferably, the lower-boiling components are expelled by a combination of methods, including, in addition to normal heating, at least one additional method selected from the group consisting of induction heating, vacuum separation, microwave heating, pressure-volume work heating, physisorption heating, chemical sorption heating, heating by an additional PCM material, photon heating, and cavitation heating. The remaining liquid, broken emulsion portion is now compositionally unstable. The previously molten heat storage material will solidify again and release the supplied fusion energy.Therefore, step c1 is immediately followed by step c2): extracting the latently stored heat from the fractured emulsion portion, which forms solid heat storage material particles while releasing heat, while maintaining a dispersion. Crucially, the starting materials are recovered with only a minimal amount of side reactions. This opens up the possibility of using the simplest, most established, and readily available systems, such as the oil sump of a two-circuit heat exchanger mentioned in the prior art, to absorb and store heat, similar to a heat pump, and release it again as needed with minimal additional energy expenditure. Using conventional plates, pipes, and heat exchanger configurations, the heat can be released locally and / or transferred to other heat-transporting media, preferably water-based heat exchangers, particularly those used in building heating systems.

[0016] Preferably, the procedure further includes the steps d1) Condensation of the gas phase component to form a condensate; e1) Combining condensate and dispersion and returning to step b1.

[0017] Preferably, in step a1 of the process, at least one long-chain saturated hydrocarbon is mixed as a heat storage material with a higher-boiling thermal oil and with lower-melting and lower-boiling hydrocarbons. Thermal oils are hydrocarbon mixtures designed for stability and durability; as such, they are relatively inert and can readily support additives such as paraffins without additional side reactions.

[0018] Preferably, in this process, lower-melting and boiling hydrocarbons are provided by adding heating oil; heating oil is readily available and inexpensive and also contains lower-boiling components that can advantageously lower the melting point of a mixture with paraffin even further. Particularly preferably in combination with a heat-retaining oil, mixtures can be obtained in which paraffin can be liquefied and emulsified at a significantly lower temperature with the absorption of heat.

[0019] Preferably, the process comprises a heating oil containing unsaturated and / or aromatic hydrocarbons. Aromatic hydrocarbons form stable mixtures and expellerable azeotropes with saturated alkanes over a wide range. Particularly preferably in combination with paraffin-based mixtures and lower-boiling components, emulsified systems and emulsifiers can be used, as disclosed, for example, in WO1996 / 33252 A1 and JP 2005 082787 A.

[0020] Preferably, the process comprises a heating oil containing residues from a refining process measuring 1 to 100 micrometers in size; finely divided suspended solids and turbidity can advantageously serve as crystallization nuclei and support the formation of solid particles with heat release in the fractured emulsion. Hysteresis effects and, in particular, the formation of supercooled, unstable mixtures are thus avoided, and the heat release is more reliable and uniform.

[0021] Preferably, the process includes coarse particle separation, which removes particles larger than 100 micrometers. Industrial oil products are frequently adjusted to desired product parameters using inexpensive additives and auxiliary agents. Such additives can decompose and form macroscopic agglomerates, which can adversely hinder the formation of fine particles. Coarse particle separation removes these agglomerates, ensuring that the process efficiency is maintained even with the most economical operating materials.

[0022] Preferably, the heat supply method utilizes at least one heat-extracting heating element with a graphite-based heating layer. Uniform, uniform heat supply avoids the side reactions that can occur at high power density and local temperature. This results in longer service life for operating fluids and more uniform heat dissipation. A uniform heating element according to WO2016 / 134705 A1 is particularly preferred; printed systems can provide electrotechnical functions very cost-effectively with minimal layer thicknesses; combined with purely inorganic, durable base materials and long-lasting carriers from the field of labels for engines and automotive components, a full-surface and extremely durable heating function can contribute significantly to a commercially attractive thermal management product.

[0023] Preferably, the process for the expulsion includes at least one heating element with a surface temperature that can be increased to over 100°C within 90 seconds. A rapidly increasing local temperature allows for the direct formation of gas bubbles on the surface, which then break off and rise hot within the emulsion. With a suitably set inlet temperature, the rising gas bubbles also destabilize the emulsion, and the emulsion breaking can advantageously be extended to larger portions of the flow volume. This results in a more uniform emulsion breaking with concentrated heat release.

[0024] Further advantages will become apparent from the exemplary embodiments. It is understood that the features and advantages described above and the following exemplary embodiments are not to be considered limiting. Additional advantageous features and combinations of features, as explained in the description and established according to the cited documents, can be implemented individually or in different combinations within the scope of the independent claims in the claimed subject matter without departing from the scope of the invention. BRIEF DESCRIPTION OF THE FIGURES

[0025] The figures – abbreviated as Fig. – illustrate, using schematic diagrams: Fig. 1 Advantageous embodiment of a device for carrying out the method in a continuous operating state. DETAILED EXPLANATION OF THE INVENTION USING EXAMPLES OF EXECUTION

[0026] In an advantageous device according to Fig.1. To carry out the method according to the invention, a hydrocarbon-based heat storage material, mixed with a heat oil and lower-boiling components, is placed in a container similar to an oil pan. The container is illustrated as a central, transversely elongated rectangle with rounded corners; analogous to an oil pan, the transition to the seal and the final, preferably pressure-tight, screwed-on lid is illustrated as a transversely oriented double line above a fill level. Preferably, all additional assemblies and devices are detachably mounted in and / or on the lid and, after loosening any existing screw connection, can be lifted out together with the lid for maintenance and / or replacement. An energy source comprising renewable energies is illustrated to the left of the container as a rectangle with rounded corners and a sun and leaf symbol.A pump is illustrated to the right of the container as a circle with a triangle inside; the downward-pointing tip of the triangle indicates the direction of flow. Typical heat consumers found in a household and / or building are illustrated to the right of the container as a rectangle with rounded corners and a house symbol. As a preliminary step, a solid heat storage material containing a heat oil and lower-boiling components is placed in the container. Step a1: Preferably, a homogenizing aid, illustrated as a figure eight with a surrounding double circle, can be used to assist the mixing until a uniform mixture is obtained. Step b1: Heat can be supplied via at least two heating elements, illustrated as vertically oriented, vertically extended rectangles, until a uniform, liquid, and completely dissolved emulsion is obtained, in which the supplied fusion energy is latently stored.By increasing the temperature at the right-hand heating element (illustrated), the emulsion can be broken in step c1); the low-boiling components of the mixture are driven out into a gas phase, illustrated as round circles or bubbles. The locally formed bubbles rise and break up the emulsion in a larger flow volume. In step c2, heat storage material particles form in the region of the broken emulsion, releasing the heat of fusion. The particles have a higher density and settle as a dispersion in a stream of particles. An advantageous guide plate is arranged below the heating element, which directs the particle stream to the left. The released heat heats the liquid in the area of ​​particle formation. To the right of the guide plate and below the right-hand heating element, an intake point for the feed pump is located.This preferred arrangement of the suction point prevents the intake of coarser, newly formed particles or decomposition products from side reactions; it also prevents the intake of rising, low-boiling gases. This design avoids the pump being burdened by flammable gases, low-boiling liquids, or particles; the pump thus operates longer and more reliably, and dangerous malfunctions or blockages are avoided. The heated medium is used for heat recovery in a household and / or building and, once cooled, is returned to the oil sump. The inlet point is located near the left heating element; preferably, the now cooler mixture is first passed over a cooling element, illustrated as a transverse rectangle, located inside the lid, before being pumped to an outlet point just below the fill level.In step d1), the low-boiling components driven into the gas phase advantageously condense on the heat sink and drip back into the mixture as condensate. The homogenizing aid combines the condensate and dispersion in step e1), and with the addition of heat, preferably from renewable energy sources, via the left heating element, a homogeneous emulsion with latently stored heat is obtained again in step b1). In continuous operation, three combined material streams, illustrated by dashed arrows, thus transport heat to the intake point: The emulsion, with its lowered melting point, latently stores heat and transports it to the right, hot heating element; the hot heating element breaks the emulsion and releases the heat, generating a gas stream and a particle stream; the released heat is extracted, utilized, and the cooled liquid is returned.The gas stream and particle stream are recombined with the recycled liquid and the heat transport can begin again as described above with step b1). INDUSTRIAL APPLICABILITY

[0027] The invention relates to a method for releasing latently stored heat and a device for carrying out the method. A disadvantage of chemical heat storage is that it is often irreversible; purely physical heat storage, on the other hand, releases heat with a delay and unevenly during cooling processes. The objective is to overcome these disadvantages. The solution is achieved with a method in which heat is stored in a stable emulsion during its formation. Subsequent breaking of the emulsion leads to reliable phase separation with the release of the previously stored heat. For the first time, heat can thus be additionally released and made available on demand with a physicochemical system analogous to a heat pump, without relying on the complex and vulnerable components of a heat pump. The most cost-effective and established systems from the field of oil-based heat exchangers and coolers can be used.For the first time, a compact and localized addition to energy management systems is now possible. A corresponding device, requiring only 1 to 2 cubic meters of space, can effectively feed thermal energy into a water-based heating circuit in a single-family home. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 1 565 510 A

[0004] US 2 004 076

[0005] GB 1 092 412 A

[0006] DD 252 664 A1

[0007] DE 31 26 534 A1

[0009] WO 1996 / 33252 A1

[0019] JP 2005 082787 A

[0019] WO 2016 / 134705 A1

[0022]

Claims

[1] Method for releasing latently stored heat comprising the steps a1) Mixing a solid heat storage material with low and / or high melting and / or boiling materials; b1) Supplying heat and melting the heat storage material until an emulsion with latently stored heat is obtained c1) Breaking of the emulsion by expelling low-boiling components into a gas phase part, leaving a remaining, liquid, broken emulsion part and c2) Extracting the latently stored heat from the broken emulsion part which forms solid heat storage material particles while releasing heat, while maintaining a dispersion. [2] Method according to the preceding claim, characterized by that the procedure continues the steps d1) Condensation of the gas phase component to form a condensate; e1) Combining condensate and dispersion and recycling to step b1; includes. [3] Method according to any one of the preceding claims, characterized by , that in step a1 at least one long-chain saturated hydrocarbon is mixed as a heat storage material with a higher boiling heat oil and with lower melting and boiling hydrocarbons. [4] Method according to the preceding claim, characterized by that lower melting and boiling hydrocarbons are provided by adding heating oil. [5] Method according to the preceding claim, characterized by that the heating oil contains unsaturated and / or aromatic hydrocarbons. [6] Method according to one of the two preceding claims, characterized by that the heating oil contains residues from a refining process measuring 1 to 100 micrometers. [7] Method according to any one of the preceding claims, characterized by, that the process includes coarse material separation, which separates particles larger than 100 micrometers. [8] Method according to any one of the preceding claims, characterized by , that at least one heat-extracting heating element with a graphite-based heating layer is provided for the supply of heat. [9] Method according to any one of the preceding claims, characterized by , that at least one heating rod with a surface temperature that can be increased to over 100°C within 90 seconds is provided for the expulsion process. [10] Apparatus for carrying out the method according to any of the preceding claims.

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