Dispersion, method for coating obiects with this dispersion and use of the dispersion The invention relates to a dispersion and also to a method for coating objects, in particular heat exchanger structures, in which this dispersion is applied on a carrier structure and is crosslinked and/or made into a film with formation of a layer. Likewise, the invention relates to heat exchanger structures coated in this way. The dispersions according to the invention can likewise be used for coatings in the construction of chemical plants and also in medical technology. Exploitation of the physical process of adsorption of gases on microporous surfaces and hence the use in thermally actuated heat pumps and refrigeration machines has various advantages: Use of waste heat or heat at a low temperature level for cooling, accompanied by energy-efficient cooling or even solar cooling; Relieving the load of the electrical network by thermally actuated refrigeration machines, Primary-energy efficient energy and cooling, as a result of the heat pump effect, environmental heat (low temperature heat) is raised to a usable level. Disadvantages result due to the equipment which to date is still very large and the poor power density associated therewith, in comparison with conventional mechanical systems. Heat pumps or adsorption refrigeration plants constructed at present have low power densities, which results in a very large construction in order to achieve corresponding cooling or heating outputs. Important approaches for making the construction more compact and increasing the power density reside in constructing the sorption chamber to be smaller. For this purpose, a large surface of the heat exchanger must be ensured and good adhesion of the sorption material thereon. Adsorption refrigeration machines and -heat pumps and also thermal stores based on the adsorption of gases on microporous solid materials are known from the state of the art, mainly water and also silica gels, zeolites and zeolite-like materials being used as operating media. Generally beds or loose adhesions are hereby used. In addition, coating technology has been developed in recent years, which is distinguished however frequently by inadequate coupling and also by a lack of adequate thermal and mechanical stability. The possible systems of binder and active sorption material and also the carrier structure have to date been very restricted. If the sorption material in the form of a granular bed or as a moulded article is used in the sorption heat pumps or sorption refrigeration pumps, heat- and material transport limit the output of the plant. Whilst the material transport is limited naturally by macroscopic granulates, the heat transport is restricted by the mainly present point contacts, e.g, spherical granulates on a carrier metal sheet. If in contrast the sorption material is used in a thin layer on the heat exchanger due to a planar composite, the material transport and above all the heat transport can be significantly improved. An adsorber element is known from DE 10 2008 050 926 Al, which consists of a carrier material on which sorbent particles with a binder material are disposed as adsorber layer. As binder, colloidal binders based on silicon oxide or aluminium oxide are used here. Starting herefrom, it was the object of the present invention to provide a stable dispersion for coating substrates, in particular metallic and ceramic substrates, which allow more simple handling during coating. This object is achieved by the dispersion having the features of claim 1 and also by the method for coating substrates having the features of claim 11 and also the coated heat exchanger structure having the features of claim 17. Uses according to the invention are found in claim 18. The further dependent claims reveal advantageous developments. According to the invention, a dispersion for coating substrates which has the following components is provided: - at least one porous sorbent selected from the group consisting of mesoporous alumino- and/or silicon compounds, metal-organic frameworks (MOFs) and/or porous coordination polymers (PCPs), zeolite-imidazolate networks (ZiFs), mesoporous molecular sieves (MCMs), activated carbons, carbon molecular sieves, hexacyanometallates and mixtures hereof, - at least one binder from the group of polyorganosiloxanes and at least one organic solvent. There is understood by sorbent, within the scope of the present invention, in particular an adsorbent. However, it can also be materials which exhibit absorption in addition. According to the invention, a dispersion of a binder and a porous solid material in an organic solvent was therewith provided, which surprisingly is stable over at least 6 h, preferably 12 h, particularly preferred 24 h and in particular 48 h. With the dispersion according to the invention, for example ceramic and metallic substrates can hence be coated with a porous solid material. The preparation of binder, sorption material and organic solvent is applied on the substrate and solidified by evaporation of the organic solvent or crosslinked in addition in the case of reactive end groups. In contrast to the aqueous dispersion, the dispersion according to the invention in an organic solvent has the following advantages: The polysiloxane binder or the precursor thereof emerges from production already in the form of an organic solution/dispersion, the preparation of an aqueous dispersion and the complexity associated therewith are dispensed with. In addition, the solution comprises no dispersion aids and fewer further processing aids. Numerous sorption materials, e.g. MOFs, such as copper(I1)- trimesate "HICUST-1" or zinc terephthalate MOF-5, are produced by solvothermal synthesis and are produced from this in the form of a dispersion in an organic solvent. If likewise the binder is present in an organic phase, the suspension for the coating can be produced directly by blending the two components. Purification of the material can be effected significantly more easily on the coated heat exchanger, complex and expensive separation steps (centrifugation) can be avoided. Many sorption materials react sensitively to water. When using organic suspensions, successful coatings of these materials were able to be produced. The possibility of producing coatings also from water-sensitive materials opens up numerous further application possibilities, for instance in the field of sensory technology or heterogeneous catalysis. With skilled process control, also open handling of particularly sensitive substances, even those requiring protective gas, in the form of an organic dispersion is conceivable. By the choice of the organic solvent, the evaporation rate can be controlled very well, which enables a more efficient drying process. Organic solvents generally have a lower surface tension, as a result of which wetting is improved relative to the undercoat and to the adsorption material and thus improved distribution of the binder on the surfaces is obtained. Liquids with low- surface tensions have in addition more homogeneous surfaces after drying. Suspensions of sorption materials in organic liquids are shown to be significantly more stable with respect to demixing and sedimentation, which substantially simplifies implementation on a large industrial scale. By varying the molecule size in the case of different solvents, it can be controlled specifically whether the solvent penetrates into the micro- and/or micropores of the adsorption material. As a result, it can be specifically ensured for example that a dissolved binder does not penetrate into the pores at all and this can no longer adhere or cause a blockage. * As a result of the low vapour pressures of many solvents, drying at high temperatures can become superfluous. Thus the drying process no longer requires further use of energy. Relative to aqueous dispersions, the dispersion according to the invention has the advantage in addition that, by the choice of a suitable organic solvent with a low boiling point in comparison to water, the evaporation rate and hence the drying process during the coating can be significantly accelerated. The dispersion according to the invention thereby has the additional advantages, with respect to the coating, that mechanically and thermally highly-loadable surfaces can herewith be produced, which enable good heat- and material transport, the technical and equipment outlay during the coating being able to be kept low. It is preferred that the at least one sorbent has nano-, meso- and/or macropores and hence is porous and has a BET surface of at least 300 m2/g, in particular of 300 to 5,000 m2/g. There should be understood here by nanopores, pores with a diameter of 0.1 to 2 nm. Mesopores have a diameter of 2 to 50 nm, whilst macropores have a diameter of at least 50 nm, in particular of 50 nm to 950 pm. A further preferred embodiment provides that the mesoporous aluminoand/ or silicon compounds are selected from the group consisting of silica gels, zeolites and zeolite-like materials, aluminophosphates, silica aluminophosphates and metal aluminium phosphates and also mixtures hereof. Preferably, the at least one sorbent is water-sensitive. There are included herein, for example MOF-5 or HKUST-1. However, also watersensitive activated carbons or mesoporous molecular sieves (MCM) exist. The at least one sorbent is preferably present as a powder, in particular with an average crystallite size of 50 nm to 20 pm and in particular with an average particle size of 200 nm to 200 pm. It is further preferred that the at least one binder is selected from the group consisting of aliphatic, olefinic and aromatic mono-, di- and triorganosiloxanes which can be crosslinl