Composition for heat transfer and heat exchanger

Abstract

Composition for heat transfer that comprises a gel (10) formed by crosslinked polymers, characterised in that the composition comprises at least one microorganism (20,21,22) that is thermophile, psychrophile or mesophile, and microorganism growing medium, wherein the microorganism is alive or in a dormant state. Heat exchanger that comprises the composition.

Description

[0001] DESCRIPTION

[0002] Composition for heat transfer and heat exchanger

[0003] TECHNICAL FIELD

[0004] The present invention relates to compositions for heat transfer and heat exchangers.

[0005] PRIOR ART

[0006] Energy saving and efficiency in heating or cooling processes has become a challenge.

[0007] The use of fossil resources has become a problem due to the negative impact on the environment. For example, this challenge can be found in heating or cooling houses or buildings where due to extreme climate changes, the need for equipment, devices and / or structural materials for buildings that allow a more efficient heating or cooling processes of houses is required. Low power or energy consumption and sustainability and recyclability of materials are also requirements that are increasingly being asked and demanded by citizens and governments.

[0008] Existing energy efficiency and thermal control technologies are mainly based on static insulation materials and conventional air conditioning systems.

[0009] Other existing energy efficient technologies can improve thermal regulation, but some may use synthetic materials or chemicals that are harmful to the environment, which can have a negative impact on sustainability.

[0010] EP0883660B1 discloses a device for storing and gradually releasing heat or cold comprising a high heat capacity composition comprising a gel of a cross-linked hydrophilic polymer.

[0011] DISCLOSURE OF THE INVENTION

[0012] The object of the invention is to provide a composition for heat transfer and a heat exchanger, as defined in the claims.A first aspect of the invention relates to a composition for heat transfer that comprises a gel formed by crosslinked polymers wherein the composition comprises at least one microorganism that is thermophile, psychrophile or mesophile, the microorganism being alive or in a dormant state. The composition also comprises a microorganism growing medium.

[0013] A second aspect of the invention relates to a heat exchanger that comprises the composition of the invention, wherein the microorganism gives rise to an exothermic or endothermic reaction due to a physical or metabolic processes on the microorganism.

[0014] A third aspect of the invention relates to the use of the composition as a thermal regulator of an environment.

[0015] Many existing energy-efficient technologies can improve thermal regulation, but some may use synthetic materials or chemicals that are harmful to the environment, which can have a negative impact on sustainability. The invention overcomes these disadvantages. The composition and the heat exchanger use the microorganism as a sensor. The microorganism functions as a biological agent which, on perceiving thermal, physical or chemical variations, is activated and triggers exothermic (heat-generating) or endothermic (heat-absorbing) reactions. The composition stores, absorbs or releases the heat to the medium or material that is in contact with the composition. These reactions allow for example the regulation of the ambient temperature, as the composition and the heat exchanger are capable of releasing or absorbing heat as necessary to maintain a stable or desired temperature.

[0016] The invention is applicable to air conditioning systems, temperature control systems, temperature protection textiles, materials for lithium batteries, household appliances or servers for instance.

[0017] These and other advantages and features of the invention will become apparent in view of the figures and the detailed description of the invention.

[0018] DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 shows a cutaway view of the heat exchanger according to one embodiment of theinvention.

[0020] Figure 2 shows a process of exothermic reactions of a composition comprising a consortium of microorganism, each microorganism having a different activation threshold temperature.

[0021] Figure 3 shows a graphic showing a temperature differential (AT) of different compositions comprising Geobacillus stearothermophilus over time (t) in days.

[0022] Figure 4 shows a graphic showing a temperature differential (AT) of different compositions comprising Thermus thermophilus over time (t) in days.

[0023] DETAILED DISCLOSURE OF THE INVENTION

[0024] Figure 1 shows a composition 100 that comprises a gel 10, preferably an hydrogel, formed by crosslinked polymers, characterised in that the composition comprises at least one microorganism 20,21,22 that is thermophile 20, psychrophile 21 and / or meshophile 22, and microorganism growing medium shown in the figure mixed within the gel 10, wherein the microorganism is alive or in a dormant state. The composition comprises a growing medium which comprises nutrients adapted for each type of microorganism.

[0025] In a preferred embodiment, the composition works thanks to the activity of heat-generating microorganisms according to their metabolic efficiency in defined thermal or temperature ranges. These microorganisms are embedded in the gel matrix that provides structural support, moisture and nutrients. Heat generation occurs in response to a physical or mechanical parameter or a chemical or biochemical element that activates exergonic and / or endergonic metabolic pathways. The composition emits or absorbs heat according to microorganisms metabolic activity, that is to say, the microbial metabolism is used as an autonomous mechanism for generating or absorbing heat when the composition is exposed to a certain condition such as mechanical or environmental stress, like agitation, changes in hydrostatic pressure, osmolarity, temperature and / or hydration / rehydration of the composition.

[0026] In an embodiment, the thermophile microorganism is selected from Rhodothermaceae, Bacillaceae, Thermaceae, Aquificaceae, Hydrogenobacteraceae, Micromonosporaceae or Rhodothermacea.In an embodiment, the mesophile microorganism is selected from Bacillaceae, Pseudomonadaceae, Desulfovibrionaceae, Lactobacillaceae, Saccharomycetaceae, Shewanellaceae, Geobacteraceae, or Acidithiobacillaceae, more preferably, Bacillus subtilis, Pseudomona aeruginosa, Desulfovibrio desulfuricans, Geobacillus, Lactobacillus sp., Saccharomyces cerevisiae, Shewanella sp., Geobacter sp., Acidithiobacillus ferrooxidans.

[0027] In an embodiment halophile microorganism is selected from Halobacteriaceae or Rhodothermaceae.

[0028] In an embodiment the psychrophile microorganism is selected from Pantoea agglomerans and Pantoea ananatis.

[0029] In the context of the invention, microorganism growing above 45 °C and below 20 °C are called thermophiles and psychrophiles respectively. The rest are called mesophiles.

[0030] In the context of the invention, halophile microorganism are the ones that retains its activity or growths at high salt concentrations.

[0031] One characteristic of these microorganism is that all of them are thermotolerant, at least in a subrange of a temperature rante between 4°C and 85°C. In the context of the invention, thermotolerant microorganism relates to any microorganism that retains its activity at the given temperature of the composition.

[0032] In a preferred embodiment, the composition comprises more than one type of microorganism. The selection of the microorganism is linked to achieving a controlled response under specific environmental conditions and maintaining its functionality in different thermal regimes in heat exchange contexts.

[0033] In an embodiment each microorganism 20,21,22 has different response to a physical or mechanical parameter or chemical or biochemical element that activate exergonic metabolic pathways, preferably, with an optimum growing temperature different to each other. Thus, in an embodiment, the composition comprises a combination of microorganism or a consortium of microorganism selected from microorganism that are thermophiles 20 and microorganism that are meshophile 22. In another embodiment, the composition comprises a combination of microorganism or a consortium of microorganism selected form microorganism that aremeshopile 22 and psychrophiles 21. In another embodiment, the composition comprises a combination of microorganism or a consortium of microorganism selected from thermophiles 20 and psychrophiles 21. In another embodiment, the composition comprises a combination of microorganism or a consortium of microorganism selected from thermophiles 20, psychrophiles 21 and meshopile 22.

[0034] The following table describes the microorganism, its activation threshold temperature (microorganism growths temperature), death or inactivation temperature (where microorganism growth stops, or death occurs) and main heat generation mechanism. The selection of the microorganism will depend on the needed temperature or range of temperature to be released or absorbed.

[0035] Species Family Activation ThreshDeath / lnactivation Heat Generation Mechaold Temperature °C Temperature nisms

[0036] Acidithio- Acidithiobacil- 15 -30°C Does not grow >40 °C Acidophilic chemolithotro- bacillus fer- laceae (Optimum 30 °C) phy: Fe2+and sulfur oxirooxidans dation.

[0037] Bacillus Bacillaceae 15 -35 No growth >50 °C; Aerobic respiration (oxisubtilis °C Vegetative cells die dative phosphorylation;

[0038] (Optimum: 30-35 °C) 50°C; Spores survive proton leakage that dissi>100 °C pates energy as heat). In anaerobiosis may ferment (e.g. 2,3-butanediol). DesulfovibDesulfovibri- 15 -38°C Does not grow >43 °C; Anaerobic sulfate reducrio desulfu- onaceae (Optimum 35-38 °C) Dies >~50 °C tive respiration (SO42— > ricans H2S using H2or organics as donors).

[0039] GeobacilBacillaceae 55-65 °C Does not grow <30 °C Aerobic respiration at lus sp. or >75 °C; Dies >80 high temperature. Some °C; Spores survive strains can ferment sug100°C ars under microaerobiosis.

[0040] GeobacilBacillaceae 45-70 °C No growth >75 °C; Aerobic respiration and lus stea- (Optimum 55-65 °C) Vegetative cells die fermentation; heat-stable rother- >75-80 °C; Spores enzyme production. mophilus survive >100 °C

[0041] Geobacter Geobacter- 20 -30°C Does not grow >37 °C Anaerobic metal-reducsulfune- aceae (Optimum 30 °C) tive respiration with exterducens nal electron transfer. HalobacteHalobacteri- 30-50 °C No growth <25 °C or Aerobic respiration with rium saaceae (Optimum ~42 °C) >55 °C; Dies >60 °C bacteriorhodopsin-driven linarum proton gradients.

[0042]

[0043] Hydroge- Hydroge- 45-70 °C Does not grow <40 °C Oxidizes H2, sulfur; fixes nobacter nobacter- (Optimum 70 °C) or >80 °C; Dies out of CO2via reverse TCA cythermophiaceae range cle.

[0044] lus

[0045] LactobacilLactobacil- 20-45 °C Dies 60 °C Homofermentative anaerlus sp. laceae (Optimum ~30-45 obic lactic fermentation °C) (glucose —> 2 lactate + heat).

[0046] PseudomoPseudomona- 4-42 °C Does not grow >42 °C; Aerobic respiration (heat- nas aerudaceae (Optimum ~37 °C) Dies >~50 °C coupled proton-leaking e- ginosa transport chain). Anaerobic denitrifying respiration (nitrate —> N2).

[0047] Rhodother- Rhodotherma- 45-77 °C No growth >77 °C; Thermophilic aerobic resmus mari- ceae (Optimum ~65 °C) Dies >80 °C piration of sugars / pro- nus teins.

[0048] Saccharo- Saccharomy- 10-30 °C Dies >45 °C Alcoholic fermentation in myces cetaceae (Optimum 30°C) anaerobiosis. Aerobic cerevisiae respiration with less heat per substrate.

[0049] Salinibac- Rhodotherma- 30-50 °C No growth >55 °C; Aerobic heterotrophic meter ruber ceae (Optimum ~37-45 Dies >60 °C tabolism with thermotoler- °C) ant pathways.

[0050] She- Shewanel- 4-30 °C No growth >35 °C; Moderate aerobic respirawanella laceae (Optimum 25-30 °C) Dies >40 °C tion; anaerobic respiration oneidensis with metals (Fe(lll),

[0051] Mn(IV)).

[0052] Thermo- Micromono- 30-55°C Dies >60 °C; Does not Aerobic polysaccharide bifida fusca sporaceae (Optimum: 55°C) grow <25 °C degradation (e.g., cellulose). Polyphosphate metabolism.

[0053] Thermo- Aquificaceae 70 °C Dies >~89 °C Aerobic chemolithotro- crinis ruber (Optimum 80-85°C) phy; oxidizes H2, thiosulfate, sulfur, and phosphite.

[0054] Thermus Thermaceae 65-70 °C Does not grow >79-80 Aerobic heterotrophic aquations °C; Dies >85 °C (thermophilic) respiration.

[0055] Many species also denitrify nitrate.

[0056] Thermus Thermaceae 50-80 °C No growth >85 °C; Aerobic respiration with thermophi(Optimum 65-75 °C) Dies >90 °C proton leakage; some delus nitrify under microaerobiosis.

[0057] Pantoe a 4°-42° No growth >40 °C; Facultative anaerobic meagglome- Enterobacteri (Optimum 10-30 °C) tabolism; primarily aerorans aceae bic respiration under normoxic conditions, with moderate heat dissipation during oxidative phosphorylation. Can also

[0058]

[0059] ferment under oxygenlimited environments. Pantoe a Enterobacte- 15.5-30°C No growth >30 °C; Facultative anaerobe; utiananatis. riaceae lizes aerobic respiration and mixed acid fermentation pathways. Generates heat through metabolic oxidation of sugars and amino acids.

[0060]

[0061] Figure 2 shows an example of a composition with a consortium of microorganisms, each microorganism having a different activation threshold temperature. The figure shows that the growing of each type of bacteria causes an increase of the temperature of the composition, said increase given rise to the growing of the next type of bacteria.

[0062] Mesophilic microorganisms of Lactobacillus, Pesudomonas and Bacillus are activated at a temperature of 25-35°C (Step 1). The growing of these microorganisms causes the increase of the temperature of the composition causing the growing of the microorganism Desulfovibrio and Geobacillus (Step 2). The growing of theses microorganisms causes the increase of the temperature of the composition to 45°C. The latter temperature causes the activation of the next consortium of microorganisms (Step 3), where Thermobifida, Shewanella and Geobacter start growing causing the increase of the temperature of the composition to 55°C, which activates the growing of microorganisms (Step 4) of Thermus, Thermocrinis, Hydrogenobacter and Desulotomaculum, increasing the temperature of the composition to 70°C.

[0063] The selection of the microorganism is linked to the achievement of a controlled response under specific environmental conditions and maintaining its functionality in different temperature ranges, preferably in heat exchange methods or processes. In an embodiment, the temperature range is between 4°C and 80°C, or between 15°C and 60°C, or between 25°C and 45°C, being more preferably, between 25°C and 60°C.

[0064] The gel matrix is formulated with natural and / or synthetic polymers (e.g. alginate, polyacrylamide), optimized to maintain thermal stability and relative humidity. It allows controlled diffusion of gases and nutrients, facilitating aerobic and anaerobic metabolism. Heat generation is a consequence of metabolic reactions, such as respiration and fermentation. The gel structure acts as a conductor and selective insulator, adapting to thermal variations without degrading. In a preferred embodiment, the gel matrix is an hydrogel. The hydrogel is a three-dimensional, cross-linked network of hydrophilic polymers that can absorb and retainsignificant amounts of water while maintaining their structural integrity.

[0065] In an embodiment, the composition comprises a viscosity between 500 and 5000 mPa-s. This viscosity allows microbial mobility and heat transfer of the composition.

[0066] In an embodiment, the composition comprises a thermal conductivity of 0.4 - 0.7 W / mK. This thermal conductivity facilitates efficient heat transfer.

[0067] In an embodiment, the composition comprises a water retention rate between 70% - 90%. This content of water maintains microbial viability and increases thermal properties of the gel.

[0068] The water retention rate is measured by a gravimetric method, wherein the weight of the hydrated hydrogel is compared before and after a controlled dehydration period under defined temperature and humidity conditions.

[0069] In an embodiment, the composition comprises a pH between 5,5 and 7,5. This pH range is optimal for microbial growth and activity.

[0070] In an embodiment, the composition comprises a oxygen permeability > 10“11m2 / s, ensuring an adequate oxygen diffusion.

[0071] The oxygen permeability is measured by using a standard diffusion cell method based on Fick’s law, wherein the oxygen transmission rate through the hydrogel is quantified under controlled temperature and humidity. This may be carried out using an oxygen-permeation analyser or a dissolved oxygen probe in a Franz diffusion cell setup.

[0072] In an embodiment, the composition comprises an elasticity of 100 - 1,000 Pa for a structural stability of the composition.

[0073] The elasticity is measured by oscillatory rheology using a rheometer, wherein the storage modulus (G') is determined under small-amplitude oscillatory shear within the linear viscoelastic region (LVR). This test is performed at controlled temperature and frequency, and follows standard protocols established in the art for hydrogel characterization. All these features being at a temperature of use of the composition which ranges between 4°C and 80°C, preferably between 25 °C and 75°C, more preferably between 25°C and 65°C.In an embodiment, the composition comprises a crosslinked polymer which is a polysaccharide, preferably selected from alginate, carrageenan nanocellulose, guar gum, xanthan gum or a combination thereof.

[0074] In an embodiment, the composition comprises a polymer crosslinking reagent selected from inorganic salts, preferably AlCh (aluminium chloride). CaCI2(calcium chloride) or CaS04(calcium sulphate). In an embodiment, the composition comprises a photo-crosslinking reagents selected from methacrylate, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone or a combination thereof.

[0075] In an embodiment, the composition comprises an organic compound or a mixture of organic compounds that is a source of carbon assimilable by the microorganism. This carbon source is understood as a source of metabolizable carbon and / or reducing equivalents usable by the microorganism of the composition, that induces, sustains or increases the generation of metabolic heat by increasing respiratory flow, or activating catabolic or anabolic pathways of low energy efficiency, or generating extracellular hydrolysis prior to assimilation or increasing maintenance metabolism, or a combinations of any of thereof.

[0076] In an embodiment, the organic compound is a branched-chain amino acids, for example, leucine, isoleucine and / or valine. In a preferred embodiment, the composition comprises a Thermus thermophilus.

[0077] In an embodiment, the organic compound is a phenolic compound, for example, a phenol, vanillin or / and cresol. Preferably, the composition comprises a Geobacillus stearothermophilus.

[0078] In an embodiment, the organic compound is a polyol, for example, glycerol. Preferably, the composition comprises a Thermus thermophilus.

[0079] In an embodiment, the organic compound is an organic acid or its salt, for example, pyruvate or mevalonate. Preferably, the composition comprises a Thermus thermophilus and / or Geobacillus stearothermophilus.

[0080] In an embodiment, the organic compound is a monosaccharide, disaccharide or a polysaccharide. For example, glucose, aravinano, hemicellulose, xylan, or / and starch.Preferably, the composition comprises a Thermus thermophilus and / or Rhodothermus marinus.

[0081] In an embodiment, the composition comprises potassium sorbate or / and geranyl pyrophosphate. Preferably, the composition comprises a Rhodothermus marinus.

[0082] In an embodiment the composition comprises by-products of the metabolism of the microorganism of the composition.

[0083] Some of the functions or roles of the components of the composition are detailed below. The specific ingredient is listed as an example and not as a limitative example for each function or role within the composition.

[0084] Alginate:

[0085] Derived from brown algae, alginate forms a gel when exposed to divalent cations (e.g., Ca2+from CaCI2or CaS04).

[0086] Provides structural integrity and mechanical strength.

[0087] Creates a biocompatible and porous network that can encapsulate active agents or microorganisms.

[0088] Controls the viscosity and flow behaviour of the gel before crosslinking.

[0089] Nanocellulose:

[0090] Improves mechanical strength and elasticity of the gel.

[0091] Enhances viscosity and shear-thinning behaviour, making the gel easier to apply while maintaining structure.

[0092] Provides a reinforcing network that improves the gel’s durability and stability.

[0093] Guar gum:

[0094] Increases the viscosity of the pre-gel solution, aiding in uniform dispersion of other ingredients.

[0095] Improves texture and stability by preventing phase separation.

[0096] Provides synergistic effects when combined with xanthan gum to create a more elastic and stable network.

[0097] Carrageenan:Enhances viscosity and provides a gel-like consistency, especially in combination with alginate.

[0098] Improves texture and stabilizes the gel matrix.

[0099] Can act as a secondary gelling agent, offering additional mechanical stability to the gel.

[0100] Xanthan Gum:

[0101] Stabilizer and synergistic thickener.

[0102] Provides pseudoplastic (shear-thinning) behaviour, aiding in easier application.

[0103] Enhances the viscosity and consistency of the gel.

[0104] Works synergistically with guar gum to create a more elastic and stable gel matrix. Improves suspension of any dispersed particles or microorganism within the gel.

[0105] Sodium Gluconate

[0106] Calcium chelating agent and pH regulator.

[0107] Acts as a chelating agent that controls the rate of calcium ion release, thereby modulating the crosslinking process.

[0108] Prevents premature gelation of alginate during formulation by temporarily binding free calcium ions.

[0109] Stabilizes pH and prevents calcium precipitation, ensuring a more uniform gel network.

[0110] CaCI2(Calcium Chloride) or CaS04(Calcium Sulphate)

[0111] Crosslinking agent.

[0112] Provides calcium ions (Ca2+) that induce ionic crosslinking of alginate chains.

[0113] CaCI2results in faster gelation, creating a more brittle and less porous gel.

[0114] CaS04leads to slower and more controlled gelation, forming a more homogeneous and stable gel network.

[0115] Choice of calcium source affects the texture, porosity, and mechanical properties of the gel.

[0116] Glycerol

[0117] Also as humectant and plasticizer.

[0118] Maintains moisture content in the gel, preventing dehydration overtime.

[0119] Acts as a plasticizer that increases the flexibility and elasticity of the gel.

[0120] Reduces brittleness and enhances the gel’s softness and smoothness.Aluminum chloride (AlCh)

[0121] Crosslinking and reinforcement agent.

[0122] Provides trivalent aluminium ions (Al3+) that can form additional ionic bridges with carboxyl groups in alginate and other polysaccharides.

[0123] Enhances the mechanical strength and rigidity of the gel by increasing the crosslink density.

[0124] Contributes to improved thermal stability and reduced water solubility, making the gel more resistant to deformation under stress.

[0125] Works synergistically with calcium-based crosslinkers to reinforce the gel network without significantly affecting biocompatibility.

[0126] Methacrylate and 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone

[0127] Photo-crosslinking system for network reinforcement.

[0128] Methacrylate groups allow for covalent crosslinking upon UV exposure, creating a secondary, more permanent network within the gel.

[0129] The photo initiator (2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone) absorbs UV light and generates free radicals that initiate polymerization of the methacrylate groups. Provides an additional layer of mechanical stability and structural integrity beyond ionic crosslinking alone.

[0130] Enhances resistance to mechanical stress, swelling, and degradation, making the gel suitable for long-term or demanding applications.

[0131] Allows on-demand curing under light exposure, enabling spatial or temporal control over gel formation.

[0132] In an embodiment, the composition comprises:

[0133] - Alginate between 1.5% and 3% w / v with respect to the total volume of water in the composition, preferably 2%;

[0134] - Calcium sulphate between 0.2% and 3% w / v with respect to the total volume of water in the composition, preferably 0.2%;

[0135] - Carrageenan between 0.5% and 1 % w / v with respect to the total volume of water in the composition, preferably 0.5%;

[0136] - Xantham gum between 0.3% and 1% w / v with respect to the total volume of water in the composition, preferably 0.5%; and

[0137] - Sodium gluconate between 0.1 % and 1 % w / v with respect to the total volume of water in the composition, preferably 0.2%.- Aluminium chloride (AICI3) between 0.2% and 1% w / v with respect to the total volume of water in the composition, preferably 0.3%.

[0138] - Methacrylate between 0.05% and 1% w / v with respect to the total volume of water in the composition, preferably 0.1%.

[0139] - 2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone between 0.1% and 1% w / v with respect to the total volume of water in the composition, preferably 0.12%.

[0140] In another embodiment, the composition comprises an organic compound or a mixture of organic compounds between 0.5% and 1% w / v with respect to the total volume of the composition, preferably 0.75% w / v, and / or potassium sorbate between 0.05% and 0.5% w / v with respect to the total volume of the composition, preferably 0.05%, and / or sodium benzoate between 0.1 % and 1.5% w / v with respect to the total volume the composition, preferably 0.1 %.

[0141] Another aspect of the invention refers to a heat exchanger that comprises the composition of the invention, wherein the microorganism give rise to an exothermic or endothermic reaction due to a physical or metabolic processes on the microorganism.

[0142] As a physical process, it may be a mechanical and / or environmental stress such as agitation of the composition, changes in hydrostatic pressure, changes in osmolarity of the composition, changes in the temperature and / or hydration / rehydration of the composition.

[0143] As a metabolic process, it may be an oxidative phosphorylation ( for example in the case of Pseudomonas and Bacillus), lactic and alcoholic fermentation ( for example, in the case of Lactobacillus), an anaerobic fermentation ( for example, in the case of Lactobacillus or Saccharomyces), an anaerobic respiration ( for example, in the case of Pseudomonas with the reduction of nitrate or Desulfovibrio with the reduction of sulphate), redox reactions with metal (for example, in the case of Shewanella, Geobacter for Fe(ll) oxidation, or Acidithiobacillus for the oxidation of sulphides) and / or phosphorous thermogenesis ( for example, in the case of Thermocrinis or Hydrogenobacter for phosphite oxidation or Thermobifida for the polyphosphate cycle).

[0144] In another embodiment the heat is generated by thermogenesis by phosphorus transformation where thermophilic microorganism (Thermomonas, B. thermantarcticus, Geobacillus, Thermus, Thermocrinis, Hydrogenobacter, Thermobifida, Caldicellulosiruptor and / or Desulfotomaculum, Thermoanaerobacter) transforms phosphorus compounds and releaseheat. These routes provide additional warmth in extreme conditions and allow for a more robust response in cold or variable climates.

[0145] In another embodiment, the heat is generated by redox reactions induced by microorganism byproducts. In this metabolic line, by-products of microorganism metabolism (such as H2, H2S, Fe2+or organic acids) react with surrounding minerals generating highly exergonic oxidationreduction reactions. For example, oxidation of Fe2+by dissolved oxygen, promoted after microorganism release of ferrous ions. This reaction releases additional heat with a positive enthalpy (AH » +150-200 kJ / mol) and negative free energy (AG°' » -125 kJ / mol), contributing to the overall temperature of the system. In this way, the composition amplifies its thermal efficiency.

[0146] In an embodiment, the composition is encapsulated or loaded in a container, preferably in a sealed or a semisealed container, preferably in a hermetic container. In a preferred embodiment, the container also comprises air in order to promote gas exchange.

[0147] In an embodiment, the container comprises a heat-conductive material, preferably selected from metals, metal alloys, carbon-based conductive materials, ceramic materials with thermal conductivity, or combinations thereof.

[0148] In an embodiment, the metal material is selected from an aluminium, stainless steel, copper, titanium or any combination thereof.

[0149] In an embodiment, the carbon-based conductive material is selected from graphene, graphite, expanded graphite, graphene-coated materials, carbon composite materials or any combination thereof.

[0150] In an embodiment, the container loaded or encapsulated with the composition is a heatgenerating module. The module acts as a functional thermal unit. In a preferred embodiment, the functional thermal unit is prepared in a sterile container of about 20 mL total internal volume, comprising up to 10 mL of the composition and maintaining headspace to promote gas exchange, preferably maintaining about 40% v / v headspace. The thermal performance of the functional thermal unit is determined as the temperature differential (AT) between the composition and a corresponding abiotic control prepared under identical conditions except for the absence of microorganism. The functional thermal unit may be characterized by averageAT, minimum AT, maximum AT, sustained AT over time, and percentage of operating time within a target AT range in a certain using conditions. In this way, the composition can be standardized as a modular heat-generating element suitable for scaling by multiplication of units and for integration into thermal panels, pipes, or other thermal regulation systems.

[0151] As shown in figure 1, the composition is encapsulated in a metallic container 30 for example, the metallic container comprising protuberances 31 that increase the surface of contact with the composition of the invention. To capture and transfer the heat generated, the composition is in contact with a heat transfer or conducting material, for example, the ones listed before, like a metallic or a graphenic material, that conducts heat from the composition to a thermal store located in contact with the construction system (walls, ceilings or other elements to be cooled or heated). This process allows the controlled release of the accumulated heat, maximizing its use.

[0152] The container described above comprising the composition of the invention is also another aspect of the invention.

[0153] The composition, container and / or the heat exchanger can be integrated into building materials. The composition allows the thermal regulation of the environment, optimizing energy efficiency in buildings by reducing dependence on conventional heating systems. The composition offers a sustainable and adaptable solution to diverse climatic conditions, promoting bioadaptive construction with less environmental impact.

[0154] In addition to its application in walls, roofs or insulating panels, the composition, container and / or the heat exchanger of the invention is highly effective in heat pump piping systems, where it acts as a preheating system for the thermal fluid. By generating and transferring heat through heat conductive materials, the composition reduces the initial energy load required by the system to reach its operating temperature, thus improving the overall efficiency of the equipment. This integration allows extending the use of passive and regenerative technologies in HVAC systems, facilitating their implementation in environments with variable thermal demands and reducing the energy costs associated with air conditioning.

[0155] Another aspect of the invention refers to a thermoregulator that comprises the composition of the invention.The thermoregulator is a device or system to maintain a constant temperature in a process or environment, either by cooling or heating as needed. The composition emits or absorbs the heat according to microorganisms' activity.

[0156] Examples

[0157] Some illustrative examples which clearly show the features and advantages of the invention are described below. However, these examples must not be interpreted as limiting the object of the invention as defined in the claims.

[0158] Example 1 : Preparation of compositions that comprises a gel formed by crosslinked polymers, a microorganism and a microorganism growing medium, wherein the microorganism is alive or in a dormant state.

[0159] Selected microorganisms: Geobacillus stearothermophilus and Thermus thermophilus.

[0160] Compositions were prepared using sodium alginate as a polymer matrix and CaS04as an ionic crosslinking agent via an internal gelation process, selected for its ability to generate homogeneous and mechanically stable gels compatible with the encapsulation of thermophilic microorganisms.

[0161] The base formulation of the hydrogel was as follows:

[0162] - Sodium alginate: 2.0% (w / v)

[0163] - CaS04: 50 mM (final concentration in the system)

[0164] - Liguid culture medium corresponding to each strain, sufficient guantity for final volume

[0165] Optionally different carbon sources (glycerol or glucose) have been included. The selection of substrates was based on criteria of biocompatibility, thermogenic capacity, chemical stability and scalability potential.

[0166] For preparation, sodium alginate was completely dissolved in the liguid culture medium corresponding to each microorganism, under constant stirring until a homogeneous solution was obtained. Subseguently, the microorganism suspension was added to the system, ensuring a uniform distribution of the biomass in the polymer solution.Gelation was induced by the controlled addition of finely powdered solid CaS04, followed by gentle stirring for 1-2 minutes, in order to promote the dispersion of the crosslinking agent and avoid the formation of local calcium gradients. The resulting mixture was immediately transferred to sterile 20 mL vials, with a final hydrogel volume of up to 10 mL per vial, maintaining approximately 40% headspace to promote oxygen diffusion.

[0167] Example 2: Long-term performance study

[0168] T o evaluate the long-term sustainability of metabolic thermogenesis, extended heat generation assays were performed over 30 days in compositions described above, compared to abiotic control (hydrogels without microorganism).

[0169] The temperature differential (AT) has been measured over 30 days, defined as the difference between the temperature of the biological system (composition with bacteria) and that of the corresponding abiotic control (composition without bacteria), measured under identical experimental conditions. The thermal differential over time (t) is defined as:

[0170] AT(t) = Tbio(t) - Tcontrol(t)

[0171] Geobacillus stearothermophilus:

[0172] The assay's operating conditions were adjusted by increasing both the initial bacterial load and the availability of carbon substrate. Specifically, the initial optical density of the microorganism culture was increased from approximately 0.2 to around 1.0, while the phenol concentration was raised from 5 mM to 15 mM. The assays were conducted in a fixed volume of 10 mL of hydrogel at 55 °C, the metabolic optimum temperature for the strain.

[0173] As shown in Figure 3, the composition supplemented with glycerol (3a) showed the greatest performance, reaching AT values of approximately 10-12 °C from day 10 onward, which remained stable until day 30. The compositions without additional substrate (3b) and with glucose (3c) also showed positive and sustained temperature increases, although in lower magnitude. In all cases, the abiotic control (3d) remained close to AT » 0 °C, confirming that the observed temperature increase is attributable exclusively to bacterial metabolic activity.Thermus thermophilus

[0174] The assay's operating conditions were adjusted by increasing both the initial bacterial load and the availability of carbon substrate. Specifically, the initial optical density of the microrganism culture was increased from approximately 0.2 to around 0.4, while the glycerol concentration was raised from 1.7 mM to 13.4 mM. The assays were conducted in a fixed volume of 10 mL of hydrogel at 70 °C, the metabolic optimum temperature for the strain.

[0175] As shown in Figure 4, the composition supplemented with glycerol (4a) showed the greatest performance, reaching AT values of approximately 14-16°C which remained stable until day 30. The compositions without additional substrate (4b) and with glucose (4c) also showed positive and sustained temperature increases, although of lower magnitude. In all cases, the abiotic control (3d) remained close to AT » 0 °C, confirming that the observed temperature increase is attributable exclusively to bacterial metabolic activity.

[0176] The following table summarizes the thermal performance over 30 days:

[0177] Type Substrate Global Minimum Maximum AT (°C) at % time within average AT (°C) AT (°C) 25-30 AT of range of AT (°C) days 10-15°C Thermus Glycerol 14 13 16 14-15 >90% thermophilus

[0178] Geobacillus Phenol 11 6 12 11 80% stearothermop

[0179] hilus

[0180]

[0181] Container format: Sterile 20 mL vial with headspace.

[0182] Volume of composition (mL): 10 mL

[0183] Dewar calorimeters (nominal capacity 500 mL) were used to measure the AT. These calorimeters are designed to minimize heat exchange with the environment and allow for monitoring temperature variations induced by bacterial metabolic activity. Compositions (up to 10 mL per vial) were placed in sterile, airtight vials, which were then inserted into the calorimeter. A digital thermometer probe (accuracy ±0.1 °C) was inserted through the vial stopper and positioned along the central axis of the composition. The calorimeter was completely sealed to minimize heat loss to the environment. As an experimental reference,abiotic controls were used, consisting of hydrogels prepared with the same protocol, composition, and volume, but without the addition of bacteria, and subjected to identical incubation and measurement conditions. The temperature data obtained were expressed as absolute temperature (°C) and as thermal differential (AT), calculated as the difference between the temperature of the biological system and that of the corresponding abiotic control at each time point. Each experimental condition was evaluated in independent replicates, allowing for reproducibility analysis and estimation of experimental variability.

[0184] Example 3: Stability of the gel matrix

[0185] The following parameters of compositions have been measured during the Long-term performance study. The used measurement methods were those described in the detailed description.

[0186] Type Thermus thermophilus Geobacillus stearothermophilus

[0187] Organic compound source Glycerol Phenol

[0188] Global average pH 7.0 -7.5 7.0 -7.5

[0189] Global average Viscosity

[0190] 2500 2500

[0191] (mPa)

[0192] Global average thermal conApprox. 0.55* Approx. 0.55*

[0193] ductivity (W / mK)

[0194] Global average water content

[0195] >90% >90%

[0196] (%)

[0197] Global average elasticity (Pa) 500 500

[0198] Temperature 60-70 °C 55°C

[0199]

Claims

CLAIMS1. Composition for heat transfer that comprises a gel formed by crosslinked polymers, characterised in that the composition comprises at least one microorganism that is thermophile, psychrophile or mesophile, and a microorganism growing medium, wherein the microorganism is alive or in a dormant state.

2. Composition according to claim 1, wherein the thermophile microorganism is selected from Rhodothermaceae, Bacillaceae, Thermaceae, Aquificaceae, Hydrogenobacteraceae, Micromonosporaceae or Rhodothermacea.

3. Composition according to claim 1 or 2, wherein the mesophile microorganism is selected from Bacillaceae, Pseudomonadaceae, Desulfovibrionaceae, Lactobacillaceae, Saccharomycetaceae, Shewanellaceae, Geobacteraceae or Acidithiobacillaceae.

4. Composition according to any of the preceding claims, wherein the composition comprises psychrophile microorganism, preferably Pantoea.

5. Composition according to any of the preceding claims, wherein the composition comprises halophile microorganism, preferably selected from Halobacteriaceae or Rhodothermaceae.

6. Composition according to any of the preceding claims, wherein the composition comprises more than one type of microorganism, each microorganism having different growing conditions to each other, preferably temperature growing conditions.

7. Composition according to any of the preceding claims, wherein the composition comprises viscosity between 500 and 5000 mPa-s, thermal conductivity between 0.4 - 0.7 W / mK, water content between 70% - 90%, pH between 5,5 and 7,5, oxygen permeability > 10“11m2 / s, and elasticity of 100 - 1,000 Pa, such features being at a temperature of use of the composition which ranges between 0 and 85 °C.

8. Composition according to any of the preceding claims, wherein the crosslinked polymer is a polysaccharide, preferably selected from alginate, carrageenannanocellulose, guar gum, xanthan gum or a combination thereof, and / or a synthetic polymer.

9. Composition according to any of the preceding claims, comprising one or more polymer crosslinking reagents selected from inorganic salts, preferably aluminium chloride, calcium chloride, calcium sulphate or a combination thereof and / or photo-crosslinking reagents, preferably selected from methacrylate or 2-Hydroxy-4'-(2-hydroxyethoxy)-2- methylpropiophenone or a combination thereof.

10. Composition according to any of the preceding claims, wherein the gel comprises an organic compound that is a source of carbon assimilable by the microorganism.

11. Composition according to claim 10, wherein the organic compound is selected from branched-chain amino acids, or a phenolic compound, or a polyol, or organic acids, or a monosaccharide, or disaccharide or a polysaccharide or a combination of any of thereof.

12. Composition according to any of the preceding claims, wherein the gel comprises, potassium sorbate or sodium benzoate and / or and a combination of any of thereof.

13. Composition according to any of the preceding claims, wherein the composition comprises by-products of the metabolism of the microorganism of the composition.

14. Composition according to any of the preceding claims, wherein the composition is encapsulated or loaded in a container, preferably in a hermetic container.

15. Composition according to claim 14, wherein the container comprises a heat-conductive material.

16. Composition according to claim 14 or 15, wherein the container comprises air.

17. Heat exchanger that comprises the composition according to any of the preceding claims, wherein the microorganism gives rise to an exothermic or endothermic reaction due to a physical or metabolic processes on the microorganism.

18. Heat exchanger according to claim 17, wherein the physical process comprises mechanical and / or environmental stress, preferably agitation, changes in hydrostatic pressure, or in osmolarity, or temperature or hy d rati on / re hydration of the composition,or a combination of any of thereof. .

19. Heat exchanger according to claim 17 or 18, wherein the metabolic process comprises an oxidative phosphorylation, or lactic or alcoholic fermentation, or anaerobic respiration, or redox reactions with metal, phosphorous thermogenesis or redox reaction induced by microorganism by-products, or a combination of any of thereof.

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