WO2007099041A1 - Working media for cooling processes - Google Patents

Abstract

Disclosed is a working pair for cooling processes and/or refrigerators, containing A) at least one coolant and B) at least one oligomer or polymer. (i) The coolant comprises a maximum of 1.0 percent by weight of halogen-containing hydrocarbons whose boiling point lies below 70°C measured as a pure substance at 101325 Pa, the percentage by weight being relative to the total weight of the coolant. (ii) The oligomer or polymer has a mean molecular weight ranging from 300 g/mol to 50,000 g/mol measured by means of GPC. (iii) The oligomer or polymer has a minimum solubility of 1.0 g relative to 100.0 g of coolant in the coolant at 50°C. And (iv) the solution viscosity of an oligomer-coolant solution or a polymer-coolant solution containing 10.0 percent by weight of oligomer or polymer is less than 700 mPas measured according to DIN 53019 at 60°C and a shearing rate of 50 Hz.

Description

 Working media for refrigeration processes

The present invention relates to new pairs of work for refrigeration processes and / or refrigeration machines. More specifically, the invention describes the use of preferably branched, oligomeric or polymeric substances as an additive or sorbent for refrigeration processes. The use of the substances according to the invention as an additive or sorbent leads to improvements in the properties of the working couple. In addition, the invention includes novel process variants for refrigeration processes with advantages over the prior art.

State of the art:

As refrigeration processes or refrigeration machines, heat pumps, heat transformers, compression steam refrigerators, absorption refrigeration plants, steam jet refrigeration plants and other sorption refrigeration machines, such as absorption and adsorption refrigeration machines of continuous and periodic operation, as well as in this invention

Diffusion chillers understood, as in Vauck, W. R. A. and Müller, H.A., basic operations chemical engineering, 10th edition, Leipzig 1994, ISBN 3-

342-00629-3 and in Lueger, Lexikon der Technik: Volume 16 Encyclopedia of Process Engineering, 4th edition, Stuttgart 1970 described.

In general, a chiller or heat pump based on the circulation of a working medium (also referred to as refrigerant), wherein at different pressure levels heat is added or removed. The basic principle is through a so-called counter-rotating Clausius Rankine process described and thus represents a direct reversal of a heat engine. Here, the refrigerant passes through the steps of (a) compression, (b) condensation, (c) relaxation and (d) evaporation.

Warmth is raised from a lower to a higher temperature level. The aim here is to lift a large amount of heat to a higher temperature level and dissipate there with a given amount of mechanical, electrical or thermal energy. In this case, it is possible to realize the change of the temperature or pressure levels by one or more stages.

The difference between chillers and heat pumps results from the temperature level used. In heat pumps, the heat (usually at the condenser) at a high temperature level is generated, e.g. used for heating purposes, while in a chiller, the heat to be supplied (usually to the evaporator) is used for Kuhlzwecken.

Heat pumps can also be designed in the form of high-temperature condensing technology, the

Condensation heat of the water vapor contained in flue gases is used above the Rauchgastaupunktes. In this case, part of the water vapor in the exhaust gas is taken up in an absorber by a hygroscopic wash solution (eg LiBr solution) and then expelled again in a desorber at a higher temperature. Both from cooling and condensation of the expelled water vapor, as well as from the Cooling the wash solution before returning to the absorber resulting heat can now be used at a high temperature level.

Compression steam refrigerators or

Compression chillers characteristically perform the cycle illustrated above using mechanical compressors. These compress the refrigerant, which is at least partially vaporous or supercritical.

Steam jet refrigerators have steam jet compressors instead of mechanical compressors and use water as a refrigerant. They evaporate a part of the water at low working pressure and extract the heat of vaporization from the residual water, which can be used as a refrigerant. Steam jet cooling plants can also be designed as open processes.

In absorption refrigeration machines, one characteristically replaces at least one stage of the mechanical compression of the vaporous refrigerant by a so-called thermal compression (alternative compression) in the above-described cycle. This consists of the absorption of the vaporous refrigerant in an absorbent, the compression of the resulting liquid mixture and a subsequent supply of heat to expel the refrigerant at a high pressure level.

There are different versions of absorption chillers and heat pumps, as in Lueger, Lexikon der Technik: Volume 16 Encyclopedia of Process Engineering, 4th edition, Stuttgart 1970 and in the review contributions by Ziegler, F., Int. J. Therm. Be. 38 (1999) 191-208, Wongsuwan, W. et al. , Applied Thermal Engineering 21 (2001) 1489-1519 and Cheung, K. et al. , International Journal of Refrigeration 19 (1996) 473-481. All

Absorption refrigerating machines are based on the use of a so-called work pair or working substance pair, consisting of a refrigerant and a

Sorbent (also called absorbent, absorbent or Absorptionsflussigkeit). The sorbent must be liquid in continuously operating sorption refrigeration machines, the concentration of the refrigerant in the sorbent

Absorption liquid is dependent on the absorption capacity, the pressure and the temperature. Within the pressure and temperature range that refrigerant and sorbent undergo in sorption refrigeration machines, both substances must be miscible, with no

May form azeotrope. The working couple can also be mixed with one or more additives with the aim of improving the absorption capacity, the heat capacity or the heat transfer and the solidification temperature of the Arbeitsspaarlosung and

Reduce decomposition phenomena. Lueger, Encyclopaedia der Technik: Volume 16 Lexikon der Verfahrenstechnik, 4th Edition, Stuttgart 1970, sets out the ideal working group from a refrigerant with a flat vapor pressure curve and thus comparatively small pressure differences in the plant, high evaporation heat and a sorption substance with the lowest possible vapor pressure. deep Solidification temperatures, small specific heat capacity and a small enthalpy of mixing together. In addition, a beneficial working couple should be chemically and thermally stable, non-toxic, non-flammable, non-environmentally hazardous and non-corrosive.

As described in Lueger, Encyclopedia of Technology: Volume 16 Encyclopedia of Process Engineering, 4th edition, Stuttgart 1970, the most important working pairs used in practice consist of (a) ammonia as refrigerant and water as sorbent or (b) water as refrigerant and Sulfuric acid or an aqueous lithium bromide solution or an aqueous lithium chloride solution as a sorbent or (c) methylamine or dimethylamine or ethylamine as a refrigerant and water as a sorbent or (d) hydrocarbons such as ethane or propane, as a refrigerant and higher boiling hydrocarbons as a sorbent together.

The working group of Nezu, Y .; Hisada, N .; Ishiyama, T .; Watanabe, K. "Thermodynamic properties of working fluid pairs with R-134a for absorption refrigeration system". Natural Working Fluids 2002, HR Gustav

Lorentzen Conference, 5th, Guangzhou, China, Sept. 17-20, 2002 (2002), 446-453. CODEN: 69EZUG CAN 140: 113462 AN 2004: 79935 CAPLUS] has for the use of (e) halogenated hydrocarbons, such as R134a (CF ₃ -CH ₂ -F) as refrigerant N, N-dimethylformamide or N, N-dimethylacetamide Sorption agent proposed. Kim, K. -S. et al. , in their contributions (1) "Ionic Liquids as new working fluids for use in absorption heat pumps or chillers "(Fifteenth Symposium on Thermophysical Properties, Boulder, CO, USA, June 22-27, 2003) and (2)" Refractive index and heat capacity of 1-butyl-3-methylimidazolium bromide and 1-butyl 3-methylimidazolium tetrafluoroborate, and vapor pressure of binary systems for 1-butyl-3-methylimidazolium bromide + trifluoroethanol and 1-butyl-3-methylimidazolium tetrafluoroborate + trifluoroethanol "Fluid Phase Equilibria 218 (2004) 215-220 working pairs with (f) 2 , 2, 2-trifluoroethanol as a refrigerant and 1-butyl

3-methylimidazolium tetrafluoroborate or 1-butyl-3-methylimidazolium bromide as a sorbent before.

As a working medium is understood in the context of this invention, occurring at least at one point of the refrigeration process maximum number of system components. In the case of absorption refrigeration systems, the working medium is thus a mixture consisting of the working pair (that is to say a system of sorption substance and refrigerant) or working pair and, if appropriate, additions of additives. For compression refrigeration systems,

Heat pump systems or other cooling processes should be understood in the context of this invention as a working medium or working pair of that mixture in the

Compressor is compressed, preferably a mixture consisting of a refrigerant and at least one additive, such. a lubricant for the compressor.

To improve the properties of a working couple, additives may be added as described in Kim, J. -S. et al., Applied Thermal Engineering 19 (1999) 217-225 or Glebov, D. and Setterwall, F., International Journal of Refrigeration 25 (2002) 538-545 or Ziegler, F. and Grossman, G., International Journal of Refrigeration 19 (1996) 301-309.

Kim, J. -S. et al. , Applied Thermal Engineering 19 (1999) 217-225 and Chua, HT et al. , International Journal of Refrigeration 23 (2000) 412-429 and Yoon, J.-I. and O. -K. Kwon, Energy 24 (1999) 795-809, for example, propose the following substances as an additive to the abovementioned working pair for absorption refrigerators LiBr + H ₂ O: (a) H ₂ N (CH ₂ ) ₂ OH, (b) HO (CH ₂ ) ₃ OH or (c) (HIGH ₂ CH ₂ ) ₂ NH.

WO 2005/113702 describes working couples for

Absorption heat pumps, absorption refrigerators and heat transformers containing a refrigerant such. As water, methanol or ammonia, and an ionic liquid.

WO97 / 49781 discloses a coolant working fluid containing at least one dendritic or hyperbranched polyester macromolecule and at least one chlorofluorocarbon coolant such as difluoroethane, trifluoroethane, tetrafluoroethane or pentafluoroethane.

Disadvantages of the prior art are that the known work pairs show a limited absorption behavior or contain substances that have too high a crystallization temperature, a high hazard potential (due to toxicity or flammability), polluting Have properties (for example due to damage to the ozone layer, or due to a high global warming potential), are corrosive or have a very high vapor pressure. Often, the working media in absorption chillers can only be incompletely separated into refrigerant and sorbent after compression because conventional refractory sorbents (such as lithium bromide) crystallize out in a concentrated state. Low-melting sorbents (such as

N, N-dimethylformamide) typically have significant volatility which, when the concentration of the sorbent is high, leads to contamination of the refrigerant, necessitating the installation of further separation equipment downstream of the extruder. However, the return of insufficiently concentrated sorption of the expeller back to the absorber is disadvantageous, since the sorbents there can therefore accommodate only correspondingly small amounts of refrigerant and thus undesirable large and energetically adverse recirculation flows arise.

The object of the present invention was to find working couples which are suitable for use in refrigeration processes and / or refrigerating machines, in particular in absorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines, compression refrigerating machines and / or heat transformers, and the at least one of the stated disadvantages, preferably as many of the disadvantages mentioned , not show. Furthermore, it was the object to find an absorbent having a sufficiently low vapor pressure in order to avoid problems in the separation of substances as possible, is stable at the expected temperatures, with the refrigerant such. Water,

Ammonia or trifluoroethanol, as good as possible miscible and can absorb it in a suitable manner.

In addition, it is advantageous to find an absorbent that is liquid as possible throughout the temperature range considered, thus preventing crystallization problems and as possible the entire existing in the absorbent refrigerant, such. As water, ammonia or trifluoroethanol, withdraw and use.

These tasks as well as others, which are not explicitly mentioned, but can be deduced from the contexts discussed herein as a matter of course or necessarily result from these, are solved by the working couple described in claim 1. Advantageous modifications of this pair of working are provided in the dependent claims on claim 1 under protection. The further claims describe particularly suitable

Areas of application of the working couple according to the invention.

In that a working pair for refrigeration processes and / or refrigerating machines, in particular absorption heat pumps, absorption refrigerating machines,

Steam jet chillers, compression chillers, heat pumps and / or heat transformers A) at least one refrigerant and B) contains at least one oligomer or polymer, wherein (i) the refrigerant, based on its total weight, at most 1.0 wt .-% halogen-containing hydrocarbons having a boiling point less than 70 ⁰ C, each measured as a pure substance at 101325 Pa , (ii) the oligomer or polymer is a weight average of the

Molecular weight Mw, measured by GPC, in the range of 300 g / mol to 50,000 g / mol, (iii) the oligomer or polymer has a solubility in the refrigerant at 50 ⁰ C of at least 1.0 g, based on 100.0 g of refrigerant , and (iv) the solution viscosity of an oligomer refrigerant solution or a polymer refrigerant solution containing 10.0 wt .-% oligomer or polymer, measured according to DIN 53019 at 60 ⁰ C with a shear rate of 50 Hz, less than 700 mPas, preferably less than 500 mPas and more preferably less than 200 mPas, wherein the

Solution viscosity is preferably determined using the RheoStress® 100 of the company ThermoHaake, it is not possible to predict a highly efficient working pair in a manner which can not be foreseen without further ado which in particular has an improved absorption behavior in refrigeration processes and / or refrigerating machines, viz. a. in adsorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines, compression refrigerating machines and / or heat transformers,

=> to provide a non-toxic, non-explosive working couple => to make available a working group with a comparatively high chemical resistance,

=> the Sorptionsmittelflüchtigkeit and thereby the

Reducing the risk potential and the separation effort,

=> to reduce the energy requirement,

=> less burden on the environment and / or

=> known from the prior art

To avoid crystallization or corrosion problems.

The working group according to the invention contains at least one refrigerant, the refrigerant, based on its total weight, not more than 1.0 wt .-%, particularly preferably at most 0.1 wt .-%, in particular no,

Halogen-containing hydrocarbons having a boiling point less than 70 ⁰ C, each measured as a pure substance at 101325 Pa includes. The halogenated hydrocarbons include, inter alia, difluoroethane, trifluoroethane, tetrafluoroethane and pentafluoroethane.

Particularly suitable refrigerants for the purposes of the present invention are those which absorb heat in a refrigeration system by low temperature, low pressure evaporation and release heat by liquefaction at higher temperature and pressure. They are specified in greater detail in DIN 8962 of August 1968 ("Refrigerants").

The refrigerant conveniently has one

Evaporation enthalpy ≥ 300 kJ / kg, particularly preferably> 350 kJ / kg, on. The best results are achieved with water, methanol, ammonia, trifluoroethanol, preferably linear hydrocarbons, in particular ethane and propane, and alkylamines, in particular methylamine, dimethylamine and ethylamine. In this case, have a refrigerant with a water solubility of at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g, in particular at least 20.0 g, each based on 100.0 g of water, measured at 25 ° C. , and especially proven against all water, trifluoroethanol and / or ammonia.

Within the scope of a further particularly preferred embodiment of the present invention, alkanes, in particular ethane and / or propane, are used as the refrigerant.

The refrigerants can each be used individually or else as a mixture of two or more of the abovementioned components.

The working pair according to the invention furthermore contains at least one preferably branched oligomer or polymer. The term "oligomer" is understood to mean a molecule having from two to eight identical or similar, preferably identical, repeat units The term "polymer" means a macromolecule having more than 8 identical or similar, preferably identical, repeat units.

In a very particularly preferred embodiment of the present invention, the working pair contains at least one, preferably branched, Polymer. Particularly preferred polymers include hyperbranched polymers and hyperbranched macromolecules with a smaller degree of branching than hyperbranched polymers.

Highly branched, globular polymers are also referred to in the literature as "dendritic polymers." These dendritic polymers synthesized from multifunctional monomers fall into two distinct categories, the

"Dendrimers" and the "hyperbranched polymers". Dendrimers have a very regular, radially symmetric generation structure. They represent monodisperse globular polymers, which are produced in multistep syntheses with a high synthetic effort compared to hyperbranched polymers. The structure is characterized by three different areas: - the polyfunctional nucleus, which represents the center of symmetry, - various well-defined radial symmetric layers of one

Repeating unit (generation) and - the terminal groups. The hyperbranched polymers, in contrast to the dendrimers, are polydisperse and irregular in their branching and structure. In addition to the dendritic and terminal units, in hyperbranched polymers, linear units also occur - in contrast to dendrimers. 1 shows in each case an example of a dendrimer (1) and a highly branched polymer (3), constructed from repeating units (2), which each have at least three bonding possibilities. With regard to the different possibilities for the synthesis of dendrimers and hyperbranched polymers, reference may be made in particular to a) Frechet JMJ, Tomalia DA "Dendrimers And Other Dendritic Polymers" John Wiley & Sons, Ltd., West

Sussex, UK 2001 and b) Jikei M., Kakimoto M. "Hyperbranched Polymers: A Promising New Class of Materials" Prog. Polym. Sei., 26 (2001) 1233-1285 and / or c) Gao C, Yan D. "Hyperbranched Polymers: From

Synthesis To Applications "Prog. Polym. Sei., 29 (2004) 183-275, which are hereby incorporated by reference and incorporated by reference as part of the disclosure of the present invention.

The hyperbranched and highly branched polymers described in these publications are also preferred sorbents for the purposes of the present invention. In this context, it is preferred that the hyperbranched polymers have at least 3 repeat units per molecule, preferably at least 10 repeat units per molecule, more preferably at least 100 repeat units per molecule, more preferably at least 200 repeat units, and still more preferably at least 400 repeat units, each at least three , preferably at least four bonding options, wherein at least 3 of these repeat units, more preferably at least 10 and more preferably at least 20 each have at least three, preferably at least four bonding options with at least three, preferably at least four further repeat units are linked. On some occasions, the hyperbranched polymers have a maximum of 10,000, preferably a maximum of 5,000 and more preferably a maximum of 2,500 repeat units.

In a preferred embodiment, the hyperbranched polymer has at least three

Repeat units, each having at least three possible binding possibilities, wherein at least three of these repeat units have at least two possible binding possibilities.

The term "repeating unit" is to be understood as meaning an always recurring structure within the hyperbranched molecule.The term "possibility of bonding" is preferably understood as meaning the functional structure within a repeating unit with which a link to another repeating unit is possible. Based on the above examples of a dendrimer or hyperbranched polymer, the repeating unit is a structure with at least three bonding possibilities (X, Y, Z):

The linking of the individual bonding units with one another can be achieved by polycondensation, by polyaddition, by radical polymerization, by anionic polymerization, by cationic polymerization

Polymerization, by group transfer polymerization, by coordinative polymerization or by ring-opening polymerization.

According to the invention, the oligomer or polymer has a solubility in the refrigerant at 50 ^° C. of at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g and in particular at least 20.0 g, in each case based on 100.0 g refrigerant.

In the context of a first particularly preferred

In one embodiment of the present invention, the oligomer or polymer is soluble in water, the water solubility at 70 ^° C. suitably being at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g and in particular at least 20.0 g, in each case based on 100.0 g of water.

In a second particularly preferred embodiment of the present invention, the oligomer or polymer is soluble in trifluoroethanol, wherein the solubility in trifluoroethanol at 50 ⁰ C expediently at least 1.0 g, preferably at least 5.0 g and more preferably at least 10.0 g , in each case based on 100.0 g of trifluoroethanol.

The measurement of these solubilities can be carried out according to the so-called piston method, wherein the solubility of the pure substance in the respective solvent is measured.

In this method, the substance (solids must be pulverized) at a temperature in the Solvent dissolved, which is slightly above the test temperature. When saturation is reached, the solution is cooled and held at the test temperature. The solution is stirred until the equilibrium is reached. Alternatively, the measurement can be performed immediately at the test temperature, if it is ensured by appropriate sampling that the saturation equilibrium is reached. Then the concentration of the test substance in the solution, which must not contain any undissolved substance particles, is determined by a suitable analytical method.

In a very particularly preferred variant of the present invention, the working pair contains at least one hyperbranched oligomer or polymer comprising polyether, polyetheramide, polyetherimide, polyethersulfone, polyester, polyesteramide, polyesterimide, polyamide, polyamidoamine, polyimideamine , Polyurethane, polyurea, polyureaurethane, polyglycerol,

Polyvinylidene fluoride, polysulfoneamine, polyethylenimine, polyacrylic acid, polyacrylate, polysiloxane, polyethersiloxane, polyimide and / or polymethacrylate units.

In this connection, the oligomer or polymer expediently contains 2 to 10,000, preferably 2 to 5,000 and particularly preferably 2 to 3,000 of these units.

According to a particularly preferred embodiment of the present invention, the oligomer or polymer has a core-shell structure, wherein the core and the shell are each made up of different repeating units. In this context, polymers having a core comprising polyethyleneimine units and a shell comprising polyether units have proven particularly useful.

In a first very particularly preferred variant of the present invention, the working pair contains at least one polyamide graft copolymer which preferably contains units of the following monomers: a) 0.5 to 25% by weight, based on the graft copolymer, of a polyamine having at least 11 nitrogen atoms and a number average molecular weight Mn of at least 500 g / mol; b) polyamide-forming monomers selected from di-, tri- and / or oligoamines, lactams and ω-aminocarboxylic acids and / or di-, tri- and / or oligocarboxylic acids and mixtures of said compounds.

According to a second very particularly preferred variant of the present invention, the working pair comprises at least one polyether graft copolymer which preferably contains units of the following monomers: a) 0.5 to 25% by weight, based on the graft copolymer, of a polyamine having at least 11 nitrogen atoms and a number average molecular weight Mn of at least 500 g / mol; b) a combination of ethylene oxide and propylene oxide as polyether-forming monomers, wherein the proportion of ethylene oxide between 0 and 100.0 wt .-%, based on the polyether structure, may vary. The oligomer or polymer according to the invention has a weight average molecular weight M _w in the range of 300 g / mol to 50,000 g / mol, favorably in the range of 300 g / mol to 45,000 g / mol, particularly preferably in the range of 300 g / mol 40,000 g / mol, in particular in the range of 300 g / mol to 20,000 g / mol.

The determination of the molecular weight, in particular the determination of the weight average molecular weight M _w and the number average molecular weight, can in known manner, for. B. be measured by gel permeation chromatography (GPC), wherein the measurement is preferably carried out in DMF and polyethylene glycols are preferably used as a reference (see, inter alia Burgath et al in Macromol Chem, Phys., 201 (2000) 782-791). In this case, a calibration curve is advantageously used, which was obtained in a favorable manner using polystyrene standards. These quantities therefore represent apparent measured values.

Alternatively, the number average molecular weight can also be determined by steam or membrane osmosis, the z. In K.F. Arndt; G. Müller; Polymer characterization; Hanser Verlag 1996

(Steam pressure osmosis) and H. -G. Elias, macromolecules structure synthesis properties, Hütig & Wepf Verlag 1990 (membrane osmosis) are described in more detail. The GPC, however, has proven to be particularly useful according to the invention.

The polydispersity M _w / M _{n of} preferred oligomers or polymers is preferably in the range of 1-10, favorably in the range of 1-8, in particular in the range of 1-6.

The viscosity of the oligomers or polymers to be used according to the invention is less than 1,000 Pas, preferably less than 800 Pas, more preferably less than 700 Pas, even more preferably less than 500 Pas, in particular less than 300 Pas, and is favorably in the range from 50 mPas to 700 Pas, especially preferably in the range of 70 mPas to 300 Pas, in particular in

Range from 100 mPas to 300 pas. It is preferably measured at 30 ^° C. and a shear rate of 30 Hz between two 20 mm plates.

The degree of branching of the oligomer or polymer is suitably in the range of> 0.0% to 75.0%, preferably in the range of> 0.0% to 70.0%, in particular in the range of> 0.0% to 65.0 %. According to a particularly preferred embodiment, the degree of branching of the oligomer or polymer is greater than 10.0%, preferably greater than 20.0%, in particular greater than 25.0%.

The degree of branching can be determined according to Frey or Frechet. A detailed description of this

Methods can be found in D. Hoelter, A. Burgath, H. Frey, Acta Polymer, 1997, 48, 30 and H. Magnusson, E. Malmström, A. Huit, M. Joansson, Polymer 2002, 43, 301.

Furthermore, the oligomer or polymer preferably determined by means of DSC glass transition temperature of less than 150 ⁰ C, preferably less than 125 ° C, especially less than 100 ⁰ C, to. The determined by means of DSC Melting temperature of the oligomer or polymer is suitably less than 300 ⁰ C, preferably less than 250 ⁰ C, in particular less than 200 ° C.

To determine the melting and the

Glass transition temperature, the use of a Mettler DSC 27 HP with a heating rate of 10 ° C / min has proven to be particularly favorable.

The vapor pressure of the oligomer or polymer is comparatively low and preferably less than 0.1 bar, preferably less than 0.07 bar, in particular less than 0.02 bar, in each case measured at 20 ^° C.

According to a first particularly preferred

In one embodiment of the present invention, the oligomer or polymer has one or more ionic structures, wherein the polymer comprises one or more groups with positive or negative partial charge, which are optionally neutralized by corresponding counterions. Particularly suitable ionic structures in this context include quaternary ammonium salts, oxonium salts, sulfonium salts, imidazolium salts, and phosphonium salts, where the cation is preferably covalently bonded to the oligomer or polymer. Particularly useful counterions include halides, especially chloride, bromide, hydroxide, sulfate, nitrate, acetate, methylsulfate, ethylsulfate, methylsulfonate, and carbonate.

In a second particularly preferred embodiment of the present invention, the oligomer or polymer has no ionic structures. Among the inventively employable oligomers or polymers are already commercially available under the brand Boltorn ^® from Perstorp AB hyperbranched polyester, as Polymin® ^®, Lupasol ^® and / or PEI ^® from BASF AG available hyperbranched polyethyleneimines and also the brand under the Hybrane ^® available from DSM BV, Netherlands hyperbranched polyester particularly favorable. Another example of a particularly suitable hyperbranched polymer are hyperbranched polyglycerols of the company Hyperpolymers with 800 g / mol <M _w <40,000 g / mol and polyethyleneimines with the type designation PEI-5 and PEI-25 as well as polyglycerols eg with the type designation PG-2, PG-5 and PG-6 of the company Hyperpolymers GmbH.

Another example of a particularly suitable hyperbranched polymer are Epomin® brand polyimines from Nippon Shokubai Co., Ltd.

In a very particularly preferred variant of the present invention, the working pair contains at least one hyperbranched polyester which preferably contains units of the following monomers: a) preferred hydroxyl components: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerol, propylene glycol, dipropylene glycol, polypropylene glycol, bisphenol A, ditrimethylolpropane , Ditrimethylolethane,

Dipentaerythritol, pentaerythritol, alkoxylated pentaerythritol, trimethylolethane, alkoxylated trimethylolpropane, neopentyl alcohol, Dimethylolpropane, sorbitol, pentaerythriol, butylglylycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2,6-hexanetriol, 1,2-octanediol and / or 1,3-dioxane-5,5-dimethanol; b) preferred anhydride or acid components: aromatic anhydrides, preferably 3, 3 ', 4, 4' benzophenone tetracarboxylic dianhydrides, pyromellitic anhydride and / or aromatic

Trimesinsäure as well as mixtures of the mentioned units.

In the context of a further very particularly preferred variant of the present invention contains

Working pair at least one linear polyether, which preferably contains ethylene oxide, propylene oxide and / or butylene oxide units. The proportion of polyether-forming ethylene oxide is preferably between 0 and 100% by weight, based on the linear polyether. Furthermore, it advantageously has at least one butyl ether or allyl ether end group.

In addition, further particularly suitable linear polyethers are described in DE 102004053167.6.

Further details of the aforementioned polymers are described in the following references, the disclosure of which is incorporated herein by reference: Hyperbranched Polysulfonamines ^■ Macromolecular Chemistry and Physics, Volume 206, Number 21 (November 2005) from 2182 to 2189 "Michael Addition Polymerizations Of TRIFUNCTIONAL Amines With divinyl sulfone" ^■ Macromolecular Chemistry and Physics, Volume 202, Number 12 (August 2001) 2623-2629 "Hyperbranched Polymers Made From A2- And BB'2-Type Monomers, 3rd Polyaddition Of N-Methyl-1,3-propanediamine To Divinyl Sulfones "^ Hyperbranched Polyurethanes

^■ WO2004101624 (BASF AG) "Method For Producing Dendritic Or Hyperbranched Polyurethanes"

^■ EP1026185 (BASF AG) "Dendrimers And Highly Branched Polyurethanes" ^■ CN02111579.6, Gao et al.

> Hyperbranched polyester

^■ WO9612754 (Perstorp AB) "Hyperbranched polyester Macromolecule OF Type"

^■ WO9318079 (DSM NV) "Hyperbranched Polyester And A Process For Its Preparation"

^■ Progress in Polymer Science, Volume 30, Number 5 (May, 2005) 507-539

^■ WO2005118677 (BASF AG) "Highly Functional, Highly Branched Or Hyperbranched polyester The Production Thereof And The Use Of The Same"

^■ US6300424 (Cornell Res Foundation Ine) "Hyperbranched Polyesters and Polyamides"

^■ DE102004026904 (BASF AG) "Highly functional, highly branched and hyperbranched polyesters and their preparation and use"

> Hyperbranched polyethers

^■ WO0056802 (Perstorp AB) "Hyper Branched Dendritic polyether And Process For Manufacture Thereof" ^ Hyperbranched polyesteramides

^■ J. Polym. Be. A 2004, 42, 3110-3115 "Development OF DSM's Hybrane Hyperbranched Polyester Amides"

> Hyper Branched Polyetherimides ^■ US6333390 (Trustees Of The University Of Illinois) "Branched And Hyperbranched Polyetherimides"

> Hyperbranched polyamine esters and polyamidoamines

^■ Progress in Polymer Science 2004, 29, 183-275 "Hyperbranched Polymers: From Synthesis to Application"

> Polyamide graft copolymers

^■ DE10005639 (Degussa AG) "polyamide graft"

^■ DE10005640 (Degussa AG) "Highly Branched Polyamide Graft Copolymers" ^■ EP1217041 (Degussa AG) "Polyamide-Polyamine Compositions With Improved Blow-Moldability"

^■ EP1217039 (Degussa AG) "Easily Flowable Polyester Molding Composition Containing Polyamide polyamines graft copolymer" ^■ EP1216826 (Degussa AG) "Polyamide-Based Laminates With An EVOH layer"

^■ EP1216825 (Degussa AG) "Manufacture of Polyamide Laminates for Solvent and Fuel-Resistant Molded Parts" ^■ EP1216823 (Degussa AG) "Manufacture of Polyamide-Polyolefin Laminates For Fuel-Resistant Molded Parts"

^■ EP1120443 (Degussa AG) "transparent polyamides Molding Compositions With Improved melt flow" ^■ EP1065236 (Degussa AG) "Highly Branched polyamides graft copolymer"

^■ EP1065232 (Degussa AG) "Polyamide-polyethyleneimine graft copolymer And Their Manufacture" > Other:

^■ Journal of Polymer Science Part A: Polymer Chemistry, Volume 43, Number 14 (JuIy 2005), 3178- 3187 "Development of an Efficient Route to Hyperbranched Polyarylene Ether Sulfones"

^■ US2002161113 (Michigan Molecular Institute) "Hyperbranched polyurea, Polyurethanes, Polyamidoamines, polyamide and polyester"

The working pair according to the invention may optionally contain further additives, such as. As corrosion and wear inhibitors, in particular H ₂ N (CH ₂ ) ₂ OH, HO (CH ₂ ) ₃ OH and / or (HOCH ₂ CH ₂ ) ₂ NH. Also, the addition of another sorbent, ie a substance that absorbs the refrigerant, such. B.

Water for the refrigerant ammonia or lithium bromide for the refrigerant water, may be useful. However, the proportion of the further sorbent is preferably less than 40.0 wt .-%, more preferably less than 30.0 wt .-%, in particular less than 20.0 wt .-%, each based on the total weight of the oligomer or polymer , In a most preferred embodiment of the present invention, the refrigerant contains no further sorbent.

The composition of the work pair according to the invention can in principle be chosen freely and tailored to the needs of each individual case. However, for the purposes of the present invention, working couples have proven to be particularly useful, depending on their total weight, from A) 0.01 to 99.99 wt .-%, preferably 0.1 to 99.9 wt .-% and particularly preferably 0.1 to 99.5 wt .-% refrigerant

B) 0.01 to 99.99 wt .-%, preferably 0.1 to 97.0 wt .-% and particularly preferably 0.1 to 95.0 wt .-% oligomer or polymer and

C) up to 5.0 wt .-%, preferably up to 3.0 wt .-%, more preferably up to 2.0 wt .-%, further additives.

The production of the working pair according to the invention can be carried out in a manner known per se by mixing the components.

Possible fields of application of the invention

Working couples are immediately obvious to the person skilled in the art. They are suitable in principle for all refrigeration processes and / or refrigerating machines and are preferably used in absorption heat pumps,

Absorption chillers, steam jet chillers or compression chillers used. Particularly suitable application areas include ventilation or air conditioning technology, such as building technology, vehicle technology, ship technology, aerospace and container technology, cold stores or refrigerated trucks, such as reefers or refrigerated trucks, for the transport of food, gases, chemicals and / or animals as well as the process technology for air drying, preferably according to the condensation principle, for the absorption of gases, central or mobile systems for heat recovery, such as cogeneration plants or solar-powered systems, refrigerators, freezers and air conditioners.

Expediently, at least one component of the working pair undergoes a cyclic process with the supply or removal of heat or mechanical energy.

Furthermore, the oligomer or polymer advantageously acts as a sorbent for the absorption of at least one vapor or gaseous refrigerant.

The separation of the refrigerant and the oligomer is preferably carried out in an expeller and subsequent condensation of the refrigerant in a return cooler. The expeller and return cooler of a

However, according to an alternative particularly preferred embodiment, absorption refrigeration plant can be replaced by at least one apparatus in which a liquid-liquid phase separation takes place and the two liquid phases are withdrawn separately. In this case, an absorbent-containing liquid phase having an absorbent concentration of at least 20% by weight and a refrigerant-containing liquid phase having a refrigerant concentration of at least 20% by weight are advantageously formed.

The present invention furthermore relates to refrigerating machines, in particular absorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines or compression refrigerating machines which contain a condenser, an expansion element, a heat exchanger and / or an absorber and the working pair according to the invention. The Chillers, in particular absorption heat pumps, absorption chillers, steam jet chillers or compression chillers preferably comprise a mixer-settler for liquid-liquid separation of the working material pair.

The improved property profile of the sorption substances and additives according to the invention can easily be checked on the basis of experimentally ascertainable absorption isotherms.

Absorption isotherms result from the amount of a volatile component (here the refrigerant), which at a given temperature and at pressures which are generally smaller than the pure vapor pressure of the refrigerant, in a very high-boiling or non-volatile liquid (here Absorbens) in an equilibrium state. Thus, the pairs of values of concentration of the liquid binary mixture and the pressure of the volatile component over the liquid at a given temperature represent an absorption isotherm. Such absorption isotherms of high boiling or non-volatile liquid substances can be measured by various dynamic or static experimental methods. as they are from

G. Sadowski, L.V. Mokrushina, W. ArIt, "Finite and infinite dilution activity coefficients in polycarbonate Systems", Fluid Phase Equilibria, 139 (1997) 391-493;

> KS Kim, BK Shin, H. Lee, F. Ziegler, Ionic fluids as new working fluids for use in absorption heat pumps or chillers: their thermodynamic properties, 15th Symposium of thermophysical properties, Boulder, Colorado (2003);

Kim, Lee, Vapor pressures and vapor-liquid equilibria of the 2,2,3-trifluoroethanol + Quinoline System, J. Chem. Eng. Data 45 (2003) 314-

316;

Y. Mun, H. Lee, Vapor-liquid equilibria of the water + 1, 3-propanediol and water + 1, 3-propanediol + lithium bromide Systems, J. Chem. Eng. Data 44 (1999) 1231-1234;

Y. Park, J.S. Kim, H. Lee, S.I. Yu, Density, vapor pressure, solubility and viscosity for water + lithium bromide + lithium nitrate + 1, 3-propanediol, J. Chem. Eng. Data 42 (1997) 145-148; Y. Kim, Y. Park, H. Lee, Solubilities and vapor pressures of the water + lithium bromide + ethanolamine system, J. Chem. Eng. Data 41 (1996) 279-281;

> J.S. Kim, H. Lee, Solubilities, Vapor pressures, densities, and viscosities of the LiBr + LiI +

HO (CH ₂ ) ₃ OH + H ₂ O System, J. Chem. Eng. Data 46 (2001) 76-73; , the disclosure of which is incorporated herein by reference.

In the absorption chillers considered here, a sorbent should absorb the refrigerant after its expansion and evaporation at a low pressure. An advantageous sorption substance absorbs as much refrigerant as possible at a given pressure, whereupon the volume and the masses of the circulatory streams are minimized. This leads to the fact that the system achieves a greater efficiency and of Their dimensions and the amount of absorber may be advantageous.

As a measure of the absorption capacity of a sorbent can alternatively to

Absorption isotherms are also used the Henry constant. This is the smaller, the greater the gas solubility in the considered sorption. Therefore, a small Henry constant is desirable. To determine the Henry constant, experimental phase equilibrium data must be used for the respective gas / absorbent system.

The Henry constant Hi, 2 of the solute 1 in the sorbent 2 results from the slope of

Fugacity for a near zero mole fraction of Component 1, i. simplified at the saturation vapor pressure of the sorbent 2 (J.Gmehling, B. Kolbe, "Thermodynamics", ISBN 3-527-28547-4, Chapter 4) The various experimental methods for determining the Henry constant are in JM Prausnitz, RN Lichtenthaler, EG de Azevedo, "Molecular Thermodynamics of Fluid Phase Equilibria", ISBN 0-13-977745-8; J. Gmehling, B. Kolbe, "Thermodynamics", ISBN 3-527-28547-4 and K. Stephan, F. Mayinger,

"Thermodynamics", Volume 2 Multi-Substance Systems and Chemical Reactions, ISBN 3-540-54459-3.

Further information on determining the property profile of working couples can be found in the above-mentioned publications. Example system I: ammonia (NH ₃ ) as refrigerant

For ammonia as a refrigerant, water according to the prior art represents the currently most advantageous sorbent. The limitation of the working temperature of the absorber to 0 ^° C., based on the freezing point of water, can be lowered by more than 10 K by using the oligomers or polymers according to the invention. Such a temperature reduction is particularly advantageous in multi-stage cryogenic plants (which can be well realized with this refrigerant due to the vapor pressure curve and the melting point of ammonia), since a lower absorber temperature via the reduction of the refrigerant vapor pressure always leads to an improved absorption behavior.

Example system II: Water as refrigerant

According to the prior art, for the refrigerant water, the lithium bromide is one of the most advantageous sorption agents. Lithium bromide has one

Pure substance melting point of 550 ⁰ C, whereupon a concentration of this sorbent - depending on the temperature to a maximum of 30 or 40 percent by mass of residual water content can take place in the expeller. Below this limit, the lithium bromide crystallizes at least partially and the continuous process comes to a standstill. The use of the oligomers or polymers according to the invention results in the already mentioned advantages of a considerably higher concentration of the

Sorption agent in the expeller. The inventive working fluid of water and an oligomer or Polymer are also less corrosive than aqueous solutions of lithium bromide.

Example System III: 2, 2, 2-trifluoroethanol as a refrigerant

According to the prior art, only the liquid organic salts are 1-butyl

3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium bromide are suitable as sorbents for 2, 2, 2-trifluoroethanol. This is by K. -S. Kim et al. in

(1) K. -S. Kim, B. -K. Shin, D. -N. Dorjnamjin, H. Lee, "Ionic Liquids: Application to an Absorption Heat Pump", 14th Symposium on Chemical Engineering Kyushu-Taej on / Chungnam, Daejon, pp5-6, Korea, December 1, (2001);

(2) K. -S. Kim, B. -K. Shin, H. Lee, F. Ziegler; "Ionic liquids as new working fluids for use in absorption heat pumps or chillers: their thermodynamic properties"; 15th Symposium of thermophysical properties, Boulder, Colorado, June 22-27, (2003);

(3) "Refractive index and heat capacity of 1-butyl-3-methylimidazolium bromide and 1-butyl-3-methylimidazolium tetrafluoroborate and vapor pressure of binary systems for 1-butyl-3-methylimidazolium bromide + trifluoroethanol and 1-butyl-3 -Methylimidazolium tetrafluoroborate + trifluoroethanol "Fluid Phase Equilibria 218 (2004) 215-220 which compared to the 1-butyl

3-methylimidazolium tetrafluoroborate superior Absorbent capacity of 1-butyl-3-methylimidazolium bromide discussed.

Surprisingly, the novel oligomers and polymers, in particular the

Graft copolymers having a polyethylenimine core and polyether chains, the graft copolymers having a polyethylenimine core and polyamide chains, the hyperbranched polyesters and the linear polyethers, a significantly improved absorbency over the prior art.

The advantageous according to the known prior art l-butyl-3-methylimidazolium bromide (BMIM Br) has a melting point of 82 ⁰ C. By the

In addition, the glass transition temperature or the pure substance melting point of the sorbent can be lowered by an amount of from 20 K to more than 100 K using the oligomers and polymers of the invention which are superior to the absorption capacity as sorbents. With these oligomers and polymers according to the invention, the sorption substance in the expeller can now be concentrated more vigorously without having to worry about crystallization of the sorption substance. Residues of refrigerant to prevent crystallization are - depending on the temperature in the sorbent - not necessary or may be much lower than in the prior art. This minimizes useless cycle flows and increases the efficiency of a cold process. It can be seen from the examples presented that the sorbent concept with the sorption agents according to the invention can be applied to all currently relevant types of refrigerant. It has been shown that in each case at least one disadvantage according to the prior art was overcome by the use of the sorption agents according to the invention.

In general, oligomers or preferably branched polymers having comparatively small molecular weights, in particular having an M _{w of} less than 20,000 g / mol, are to be preferred for these applications, since these generally have a higher mass-related absorption capacity.

In addition to the use of branched oligomers or polymers as sorbent or additive in refrigerators of the prior art, the use of these substances in absorption refrigeration machines according to the invention, in which at least the expeller is replaced by one or more settlers, leads to energetic advantages over the prior art. Below is an example of an advantageous embodiment of the method according to the invention with reference to FIG. 2.

The working pair is guided to the absorber (4) by means of a pump (5) in at least one heat exchanger (6a) in which _it absorbs heat Q or write. Due to the absorption of heat or heat dissipation, the working solution which is liquid at point (4) and which, in addition to the sorption substance and the refrigerant, may also contain additives, is present in a liquid-liquid solution. Miscibility gap, which is characterized by an upper or lower critical solution temperature. At the heat exchanger (6a) is followed by at least one phase separation apparatus, the Settier (7), in which the working solution in two liquid phases, a

Sorbent-rich and a refrigerant-rich phase, segregated. The settler may contain coalescence and sedimentation internals. The refrigerant-rich phase is then passed through at least one heat exchanger (6b) and a throttle (8a). In the evaporator (9) the largely liquid refrigerant absorbs heat Q _to and is thereby at least partially transferred in the vaporous state of aggregation. Subsequently, a new heat transfer in a heat exchanger (6b) take place before the refrigerant-rich phase introduced into the absorber, absorbed by a sorbent and thereby the heat of absorption Q _{ab is} discharged.

After the settler (7), the absorbent-rich phase can be conveyed again through a heat exchanger (6a) before it is then expanded to absorber pressure in a throttle (8b) and fed to the absorber (4).

Depending on the sorption agent and refrigerant in the process according to the invention in the settler (7) is a temperature of -50 ⁰ C <T <250 ⁰ C, preferably from -20 ⁰ C <T <200 ⁰ C and particularly preferably from -10 ⁰ C <T <180 ° C at a settler settler system pressure between 0.01 bar <P <200 to choose bar, in the absorber (4) a temperature of -70 ⁰ C <T < 200 ° C, preferably from -50 ⁰ C <T <150 ⁰ C and particularly preferably from -30 ⁰ C <T <100 ⁰ C at an absorber system pressure between 0.01 bar <P <60 to choose bar and in the Heat exchangers (6a) and (6b) each have a heat transfer area of 0.1 m ² <A <300 m ² , preferably from 0.2 m <A <200 m and more preferably from 0.3 m ² <A <150 m ² to provide.

As an alternative to the illustrated advantageous embodiment of the method according to the invention, the sorption substances or additives according to the invention can also be used in at least one stage of a single-stage or multi-stage absorption refrigeration system with at least one heated expeller and subsequent refrigerant condenser - as exemplified in Vauck, WRA and Müller, HA, Basic Operations of Chemical Process Engineering, 10th edition, page 527, Leipzig 1994, ISBN 3-342-00629-3 described - are used.

Further advantageous embodiments of the method according to the invention are obtained when one or more stages of a multi-stage refrigerator have been replaced by the embodiment depicted above or sorbents or additives according to the invention are used in at least one stage of the refrigerator. Examples

Examples 1 to 5 illustrate the invention for working couples of water as a refrigerant and one of the oligomers or polymers A to E as a sorbent.

Polymer A is a hyperbranched polyesteramide (polymer of 2,5-dihydrofurandione with 1,1'-imino bis [2-propanol]) having an average molecular weight of 1200 g / mol and an average of 8 OH groups per

Molecule that is commercially available from the Dutch company DSM under the name Hybrane S1200.

Polymer B is a 16 OH endblocked polyamidoamine dendrimer having a molecular weight of 3256 g / mol, available from Dendritech Inc. (Michigan, USA) under the product name PAMAM-OH.

Polymer C is a hyperbranched polyglycerol having an average molecular weight of 1400 g / mol, an average of 20 OH groups per molecule and a polydispersity of 1.5. The polymer can be obtained under the name PGl from the German company Hyperpolymers GmbH.

Polymer D is a hyperbranched polyglycerol with an average molecular weight of 6000 g / mol, an average of 80 OH groups per molecule and a polydispersity of 2.4. The polymer may be under the

Designation PG3 be purchased from the German company Hyperpolymers GmbH. Oligomer E is a polyethylene glycol having an average molecular weight of 600 g / mol, which is available from Conlac GmbH under the name PEG 600.

For mixtures of 99.8 wt .-% polymer or oligomer and 0.2 wt .-% of water with the in S. Iyoki and T. Uemura, Int. J. Refrig. (1989) Vol. 12, pages 278-282 described the method of partial water pressure over the mixture at 110 ⁰ C and 40 ⁰ C determined. The results are summarized in Table 1. All mixtures were liquid and single-phase.

Table 1

Water partial pressure of working pairs of water and polymer or oligomer

For the working pair of water and lithium bromide known from the prior art, a water partial pressure of 211 mbar at 110 ^° C. and 7 mbar at 40 ^° C. were determined by the same method for the maximum usable lithium bromide concentration of 60% by weight. The examples show that with the working pairs according to the invention a lower partial pressure of water can be achieved than with the known from the prior art working pair of water and lithium bromide. This makes it possible, the sorbent in the expeller one

Concentrate absorption refrigeration system or absorption heat pump higher than is possible with lithium bromide as a sorbent.

Claims

Claims: 1. Working pair for refrigeration processes and / or refrigerators, containing A) at least one refrigerant and B) at least one oligomer or polymer, characterized in that (i) the refrigerant, based on Total weight, not more than 1.0 wt .-% of halogenated hydrocarbons with a Boiling point of less than 70 ⁰ C, measured in each case as pure substance at 101325 Pa, comprises, (ii) the oligomer or polymer has a weight average molecular weight Mw, measured by GPC, mol / comprising mol in the range of 300 g / to 50,000 g, (iii) the oligomer or polymer has a solubility in the refrigerant at 50 ^° C of at least 1.0 g with respect to 100.0 g of refrigerant, and (iv) the solution viscosity of an oligomer refrigerant solution or a polymer refrigerant solution containing 10.0 wt .-% Oligomer or polymer, measured according to DIN 53019 at 60 ⁰ C with a shear rate of 50 Hz, less than 700 mPas. 2. Working pair according to claim 1, characterized in that it contains water, methanol, ammonia, trifluoroethanol, at least one hydrocarbon and / or at least one alkylamine as a refrigerant. 3. Working pair according to claim 1 or 2, characterized in that the refrigerant has a water solubility of at least 1.0 g based on 100.0 g of water, measured at 25 ° C, has. 4. Working pair according to at least one of the preceding claims, characterized in that the oligomer or polymer has a determined by DSC glass transition temperature less than 150 ⁰ C. 5. Working pair according to at least one of the preceding claims, characterized in that the oligomer or polymer has a melting point determined by means of DSC less than 300 ⁰ C. 6. Working pair according to at least one of the preceding claims, characterized in that the vapor pressure of the oligomer or polymer, measured at 20 ⁰ C, less than 0.1 bar. 7. Working pair according to at least one of the preceding claims, characterized in that the oligomer or polymer is branched. 8. Working pair according to claim 7, characterized in that the oligomer or polymer has a degree of branching DB Frey or Frechet of 0% <DB <75.0%. 9. A working pair according to claim 7 or 8, comprising at least one hyperbranched polymer. A working pair according to at least one of the preceding claims, characterized in that the oligomer or polymer comprises polyether, polyetheramide, polyetherimide, polyethersulfone, polyester, polyesteramide, polyesterimide, polyamide, polyamideamine, polyimideamine, polyurethane , Polyurea, polyureaurethane, polyglycerol, polyvinylidene fluoride, polysulfoneamine, polyethyleneimine, polyacrylic acid, polyacrylate, Polysiloxane, polyethersiloxane, polyimide and / or Polymethacrylateinheiten. 11. Labor pair according to claim 10, characterized in that the oligomer or polymer contains 2 to 10,000 of these units. 12. A working pair according to at least one of the preceding claims, characterized in that the oligomer or polymer comprises at least one ionic structure. 13. Working pair according to claim 12, characterized in that the oligomer or polymer at least one quaternary ammonium, oxonium, Sulfonium, imidazolium and / or phosphonium group. 14. Working pair according to at least one of the preceding claims, consisting of A) 0.01 to 99.99% by weight of refrigerant B) 0.01 to 99.99 wt .-% oligomer or polymer and C) up to 5.0% by weight of further additives. 15. Use of pairs of work according to at least one of claims 1 to 14 in refrigeration processes and / or refrigeration machines. 16. Use according to claim 15, characterized in that at least one component of the working couple undergoes a cyclic process with supply or removal of heat or mechanical energy. 17. Use according to claim 15 or 16, characterized in that the branched oligomer or polymer acts as a sorbent for the absorption of at least one vapor or gaseous refrigerant. 18. Use according to any one of claims 15 to 17 in the ventilation or air conditioning technology, in vehicle technology, in marine engineering, in aerospace or in container technology. 19. Use according to any one of claims 15 to 17 for cold stores or refrigerated transporters. 20. Use according to any one of claims 15 to 17 in process engineering for air drying, for the absorption of gases, in central or mobile plants for heat recovery. 21. Use according to any one of claims 15 to 17 in refrigerators, freezers or air conditioners. 22. refrigerating machines, comprising at least one heat exchanger, an expansion element, an absorber and a working pair according to at least one of claims 1 to 14. 23. A refrigerator according to claim 22, further comprising a mixer-settler.