Heat pump device for energy-efficient generation of a process heat, dryer device for drying material to be dried, and method for operating a heat pump device

Abstract

The invention relates to a heat pump device for the energy-efficient generation of a process heat with a cyclical process fluid, an evaporator and at least one compressor, wherein the heat pump device has a first mixing separator in a second pressure stage, wherein the first mixing separator has a first connection for the inlet of vaporous cyclical process fluid, a second connection for the inlet of condensed cyclical process fluid and a third connection for the outlet of vaporous cyclical process fluid and a second compressor is connected downstream of the mixing separator, so that outgoing vaporous cyclical process fluid can be compressed in the second compressor from the second pressure stage to a first pressure stage and that cyclical process fluid condensed in a heat exchanger for transferring process heat to at least one assignable heat sink can be fed back into the first mixing separator of the second pressure stage, wherein at the same time vaporous cyclical process fluid from the first compressor can be fed into the mixing separator, and the at least first mixing separator has a fourth connection for the outlet of condensed cyclical process fluid, so that the condensed cycle process fluid which emerges can be fed back directly or indirectly into the evaporator and / or can be fed to the at least second compressor. The invention further relates to a dryer device and to a method for operating a heat pump device.

Description

Heat pump device for energy-efficient generation of process heat, drying device for drying a material to be dried and method for operating a Heat pump device

[0001] The invention relates to a heat pump device for the energy-efficient generation of process heat, wherein the heat pump device has a heat-absorbing side, a heat-emitting side, a cycle fluid and an evaporator on the heat-absorbing side, and a heat exchanger and at least one heat sink can be assigned to the heat pump device on the heat-emitting side and at least one heat source on the heat-absorbing side, wherein liquid cycle fluid can be indirectly heated by means of the evaporator by supplying heat from the assignable heat source and can be evaporated at a pressure stage of the evaporator, and the heat pump device has at least one first compressor downstream of the evaporator, wherein vaporous cycle fluid can be compressed from the pressure stage of the evaporator to a second pressure stage by means of the at least first compressor.Furthermore, the invention relates to a drying device for drying a material to be dried by means of a heated process gas stream and a method for operating a heat pump device.

[0002] In the course of the energy transition and the current crisis in the natural gas supply, heat pump processes are becoming the focus of process heat generation. While heat emission While residential heating occurs at low temperatures, industrial heating processes often require significantly higher temperatures. For example, industrial drying processes require large amounts of heat, sometimes several MW, at high temperatures well above 100 °C, often above 200 °C, and represent one of the largest emitters of greenhouse gases in the industrial sector because the high temperatures have traditionally been generated by combustion processes of solid, liquid, or gaseous carbon-based fuels.

[0003] When generating process heat through combustion processes or electrically powered heaters, primary energy input is required approximately equal to the process heat output to be generated. To decarbonize industry, primary energy input for process heat generation can and should be drastically reduced by largely replacing the combustion processes previously required to achieve temperatures above 120 °C to over 200 °C with suitable, highly efficient, high-temperature heat pumps with electric drives.

[0004] In general, heat pump processes for generating process heat can be characterized by the heat output coefficient COPh as the quotient of the heat output related to the drive power, the required temperatures of the heat-absorbing side, the achievable temperatures of the heat-emitting side and the resulting temperature difference between heat absorption and heat emission. So far, the development of economical High-temperature heat pumps with heat output above, for example, 200 °C have too low a temperature rise, since, due to thermodynamic relationships in the cycle, the heat output factor decreases with increasing temperature rise. Therefore, the operation of known cycles has so far required high heat source temperatures on the heat-absorbing side, which in themselves represent high-quality heat sources with a correspondingly uneconomically high price, or are not even available as waste heat sources and would have to be manufactured.

[0005] The value of process heat is usually measured according to its temperature level. In a heat pump cycle, the temperature level of the released process heat is typically achieved by compressing the cycle fluid. The specific drive work for compression corresponds to the expenditure, i.e. the destruction, of specific exergy. The level of specific exergy destruction, in turn, correlates with the minimum compression pressure that must be overcome for the cycle fluid to reach the required temperature so that process heat can be transferred at the highest sink temperature.

[0006] The higher the highest required sink temperature for the transfer of process heat, the more specific exergy is destroyed and the higher the quality of the generated process heat. Accordingly, for the generation of lower quality process heat less specific exergy destruction is required than for higher-quality process heat.

[0007] Heat pump processes can generally be divided into cycle processes without phase transition of a cycle gas and those with phase transition of a cycle fluid from liquid to gaseous in an evaporator on the heat-absorbing side, whose phase transition from gaseous to liquid occurs either by condensation in a condenser or by transcritical cooling in gas coolers.

[0008] Known high-temperature heat pumps without phase transition of the always gaseous cyclic process gas, such as rotary heat pumps from the Austrian company ecop Technologies GmbH from AT-4531 Neuhofen an der Krems (www.ecop.at), which are based on a counterclockwise Joule process, can heat sink temperatures of 150°C with relatively high heat performance factors of around 4, but only achieve a very small temperature difference of around 55 K and, due to their design, are limited in the maximum heat output per heat pump. A multi-stage arrangement of such heat pumps to overcome an overall higher temperature difference is possible in principle, but fails due to the significantly higher drive power with constant heat output, significantly reduced heat performance factors and the associated low cost, as well as the design-related limitations of the heat output that can be absorbed and released.

[0009] In heat pump cycles with a phase transition of the cycle fluid through evaporation, a distinction is made between heat pumps with condensation of the cycle fluid on the heat-emitting side and transcritically operated heat pumps with heat emission from the cycle fluid in gas coolers at supercritical pressure, for example with carbon dioxide (CO2) as the cycle fluid. The key difference between the two cycle types with phase transition of the cycle fluid is that transcritically operated heat pumps transfer heat output over an extended temperature range and not at a fixed temperature plateau, as is the case with condensation operation.

[0010] In the recent past, transcritically operated CO2 heat pumps have already been built up to sink temperatures of around 120 °C, as described, for example, in EP 2 321 589 B1. Although no condensation pressure can be achieved with transcritically operated heat pumps because no actual condensation takes place in a condenser, a correspondingly high compression pressure to a pressure above the critical point of the cycle fluid must be achieved for heat transfer in a gas cooler from the supercritical cycle fluid to the heat sink to be supplied with the highest temperature, by expending mechanical work for compression up to the corresponding supercritical pressure on the heat-emitting side.

[0011] An advantage of transcritical heat pumps with supercritical gas coolers is that the cycle fluid in the gas cooler can only cool to a temperature above the inlet temperature of the heat sink and then still retains a portion of its specific heat, which may still be sufficient to supply process heat to lower-quality heat sinks. While this requires mechanical work to exceed the highest sink temperature, no additional mechanical compression would be required for the subsequent supply to a lower-quality heat sink.

[0012] This advantage of transcritically operated heat pumps is, however, at the same time a considerable disadvantage, since the successive cooling of the supercritical cycle fluid by heat transfer in the gas cooler requires that the respective heat sink still receives sufficient process heat despite this successive temperature loss of the cycle fluid. For this to happen, the inlet and outlet temperatures of the respective heat sink must be sufficiently low. If this is not the case, and the lowest sink temperature is still too high to cool the supercritical cycle fluid to temperatures far enough below the critical point, the transcritical process becomes uneconomical or even impossible, since the evaporator on the heat-absorbing low-pressure side of the transcritical cycle often cannot be operated correctly.

[0013] A further significant disadvantage of transcritically operated heat pumps with CO2 as a refrigerant when it comes to supplying sink temperatures well over 120°C with process heat is the high compression pressures of well over 120 bar in combination with the high CO2 outlet temperature of well over 130°C, which presents the design of the necessarily oil-lubricated piston or screw compressors with as yet unsolved technical problems with regard to material strength and temperature resistance of the oil. The mere fact that the compressors have to be oil-lubricated because the frictional forces at the high pressures are far too high for oil-free compression requires functioning oil management to ensure that downstream units, such as gas coolers and evaporators, are not impaired in their effectiveness by the oil component carried along in the cycle.

[0014] An additional disadvantage of known heat pumps using refrigerants such as CO2, NH3, and hydrocarbons is their limitation when heating the heat-absorbing side of heat sources significantly above 30-40 °C. Even if this can be achieved with complex technical means, the technically achievable temperature increase is so small that a high temperature of over 200 °C cannot be achieved on the heat-emitting side for process heat transfer to a heat sink.

[0015] In a heat pump cycle with condensation of the Cycle process fluids must be produced The condensation temperature for heat transfer must be sufficiently higher than the temperature of the heat sink to be supplied with the highest sink temperature. The highest required sink temperature and the selection of the cycle fluid with regard to its pressure-dependent condensation temperature therefore determine the required pressure in the condenser, i.e. the heat exchanger of the heat sink, in which heat is released from the heat pump cycle. The condensation pressure must usually be achieved by compressing the cycle fluid using mechanical work, i.e. the destruction of exergy.

[0016] The current development of new heat pumps with condensation of a cyclic process fluid has for some time been concentrating on the investigation of suitable cyclic process fluids with regard to achieving the highest possible condensation temperature with the lowest possible condensation pressure on the heat-emitting side and, at the same time, a high evaporation pressure with the lowest possible evaporation temperature on the heat-absorbing side.

[0017] However, many fluids suitable for use in cycle processes, also called refrigerants, which come as close as possible to these properties, generally have very poor environmental compatibility in terms of climate damage, ozone depletion, flammability or toxicity. Therefore, natural refrigerants such as CO2, NH3 and less harmful but flammable hydrocarbons are increasingly being used. However, it remains to be noted that in almost all There are strong to very strong restrictions on the maximum sink temperature and the achievable temperature rise for the refrigerants currently approved by the EU Commission.

[0018] These include, for example, industrial heat pumps using the natural refrigerant NH3, which are typically operated with condensation of the cycle fluid and were previously referred to as high-temperature heat pumps if the maximum possible sink temperature was, for example, 80-90°C. This is due to the critical point of NH3, which is 132.35°C and 113.53 bar, meaning temperatures of 80-90°C are already just below the critical point. At 200°C, NH3 is already supercritical and would no longer be condensable, but could only be used in a transcritical process under very high pressures.

[0019] Due to the relatively low critical point of NH3, a pressure of over 62.55 bar must be overcome for its condensation at 100°C, for example. This high pressure level requires a high specific compressor work and increases the operating costs for compression. In addition, it makes both the design of oil-lubricated compressors and the design of heat exchangers complex and expensive. In addition, the specific condensation enthalpy of NH3 at 100°C is only 715.7 kJ / kg, which means that the resulting heat performance figures are uneconomically low. Temperature level of 100°C is not sufficient for many industrial processes.

[0020] For CO2, the critical point is even lower, namely at 31.06°C and 73.83 bar. Thus, CO2 can no longer be condensed outside the two-phase region above 31.06°C, but can only be used for heat transfer in a transcritical process above the critical pressure. Due to the high pressures involved, similar restrictions apply to its design and operation as for NH3.

[0021] The aforementioned cycle fluids are gaseous under standard conditions and, due to their high vapor pressures, for example at 0°C of 34.85 bar for CO2 and 4.29 bar for NH3, are very well suited to generating process cooling, which underlines their good suitability as refrigerants. An advantage of both fluids is their relatively low specific volume, for example at an evaporation temperature of 54°C, which is 57 l / kg for NH3 and 5.6 l / kg for CO2. This allows for relatively small apparatus sizes even at high evaporation rates. In the supercritical range, the specific volumes of both fluids are even below 10-20 l / kg, which is very advantageous for the size of heat exchangers. However, here again the high supercritical pressure comes into play, which makes the design of the apparatus complex.

[0022] The use of steam as a cycle fluid is particularly important in power plant technology as a right-handed The power generation process is already known, while electrically driven heat pumps using steam as a fluid cycle in a counterclockwise working process have not yet been designated as such. However, when so-called water heat pumps are currently discussed, this generally refers to heat pumps that heat a water stream at least on the heat-emitting side and possibly also cool a water stream on the heat-absorbing side. However, their fluid cycle is not water, but rather another fluid.

[0023] Widely known as a type of heat pump, but not usually constructed in the form of a conventional cycle, is the compression of water vapor, for example by means of the frequently used vapor recompression to raise the condensation temperature of water vapor, in order to make it available for heat transfer, often at a slightly higher temperature level, as is the case, for example, in modern evaporation processes with mechanical vapor recompression. Here, with a low temperature lift of just a few Kelvin, very high calculated heating output figures can be achieved, some of which are well over 20. However, this is a misleading assessment, since it is not a counterclockwise cycle that is materially closed, as is typical for heat pumps.In any case, a higher temperature increase of more than 10-20 Kelvin generally requires a multi-stage structure, which significantly reduces the overall achievable heating performance figure.

[0024] Compressors for water vapor are built in various designs as turbo machines, for example on the one hand in the form of radial blowers for low compression rates below 2 and high volume flows at low final pressures below 5 bar or on the other hand as turbo compressors for medium compression rates up to about 3 and higher final pressures up to about 20 bar, as well as as positive displacement machines in the design of rotary piston compressors for high volume flows at medium compression rates or piston machines for high compression rates up to 6 and particularly high final pressures up to over 70 bar.

[0025] For example, Spilling Technologies GmbH in Hamburg (www. spilling.de) describes such piston steam compressors for high discharge pressures up to 70 bar. However, due to their design, they generally cannot draw in vacuum steam below 100°C, but only steam well above atmospheric pressure. These piston steam compressors are now manufactured up to a pressure rating of approximately 40 bar, in a design limited to a steam temperature of approximately 250°C, even without oil lubrication of the pistons.In order to achieve this, a defined amount of water is injected into the sucked-in steam stream before it enters the cylinders to reduce the superheat in the compressor, so that supersaturated wet steam with a steam portion XD and at the same time a liquid portion (1 - XD) is created before compression, whereby the liquid portion ensures sufficient lubrication of the pistons during compression and due to the temperature increase during the polytropic. Compression evaporates, so that ideally saturated vapor without any significant superheat is present at the compressor outlet.

[0026] The company Piller Blowers & Compressors GmbH in Moringen (www.piller.de) describes steam compressors with a fan design, which are used for vapor compression in vacuum conditions and are currently built for outlet pressures of up to 5 bar gauge. To achieve a higher temperature lift, these compressors are connected in series in multiple stages. Due to the temperature-dependent material strength of the compressor impellers, it is necessary to inject a defined amount of water for cooling into the drawn-in steam stream before it enters the compressor impeller at the high circumferential speeds required for compression.

[0027] Similarly, the Boldrocchi Group Srl in Biassono, Italy (www.boldrocchigroup.com) describes steam blowers and turbocompressors in fan design for compression ratios between approximately 1.2 and 3.0 and final pressures up to 100 bar, as well as multi-stage arrangements of various compressors to achieve a higher temperature lift. The Boldrocchi Group also describes the supersaturation of steam with injected water before it enters the compressor impeller to reduce superheat in the compressor.

[0028] The advantage of wet steam compression is the continuous cooling during compression by the evaporating liquid component. Compression due to compensated superheating occurs at lower temperatures overall than would be the case with dry, superheated steam, whereby the specific volume during wet steam compression is lower in the superheating region compared to uncooled compression of dry steam, which reduces the size of the compressors for the same mass flow.

[0029] A disadvantage of compressing wet steam, however, is that in addition to the mass flow of the vaporous steam portion XD, the mass flow of liquid water (1 - XD) injected before compression, which evaporates during compression, accelerates to the high circumferential speed in the compressor impeller and must be compressed to the outlet pressure. In addition, this water portion of the wet steam, which evaporates to saturated steam within the compressor impeller, experiences an increase in its specific volume by a three-digit factor and, due to the increasing volume flow, a corresponding acceleration, which leads to a higher specific drive torque related to the mass flow.

[0030] A further disadvantage is that the water portion of the wet steam enters the compressor impeller in liquid form and hits the impeller structure as droplets, which leads to greater mechanical stress on the surfaces and higher fluid friction within the compressor impeller.

[0031] In addition, the injected water must be treated or at least decalcified to avoid limescale deposits in the compressor.

[0032] In particular, in a multi-stage compression arrangement for supplying a saturated steam mass flow at the outlet of the last compressor stage, each of the compressor stages must compress the saturated steam mass flow exiting from the previous stage and additionally the water mass flow injected in the respective stage, which is required to reduce the superheat.

[0033] The combination of these disadvantages increases the overall specific drive power of the compression in relation to the delivered saturated steam mass flow.

[0034] Another significant disadvantage of the known vapor compression or steam compression for the provision of higher-quality steam using low-temperature waste heat between 60-80 °C, for example in the form of vacuum steam, is that the condensed steam, when transferring condensation heat to a heat sink with a high sink temperature, i.e. the liquid steam condensate, still has a temperature that is significantly too high to be able to be re-evaporated in a closed-loop process using the same low-temperature waste heat source between 60-80 °C. Thus, in addition to the construction of a closed-loop process, which could be described as a heat pump cycle, the known vapor compression lacks the necessary Cooling of the condensed cycle fluid to the Evaporation temperature of the heat-absorbing Low pressure side .

[0035] In addition, industrial processes often have multiple heat sinks that require process heat, and these often even operate at different temperature levels. For a coupled supply of such different heat sinks with a common heat pump process in condensation mode, its design must also be based on the supply of the highest-value heat sink with the highest required heat sink temperature.

[0036] A typical example of industrial processes with high process heat requirements, sometimes several megawatts up to a high temperature level of over 200 °C, are large-scale drying processes, such as spray-drying processes for powder production. In such spray-drying processes, the high flow rates of used, steam-enriched process gas generally generate large amounts of waste heat, which are of a similar magnitude to the heat required to heat the drying process. However, due to the nature of the process, this waste heat is consistently generated at a low temperature level, for example, between 60 and 80 °C.

[0037] If heating with process heat is to take place at a high sink temperature of, for example, over 200 ° C, then conventional heat pumps can only achieve a high heating performance figure if the heat pump Cycle process, a corresponding amount of heat is supplied on the low-temperature side and the technically achievable temperature lift is not less than the difference between the highest required sink temperature and the lowest available temperature level of the low-temperature heat source.

[0038] In order to upgrade low-temperature waste heat streams from a temperature level frequently encountered in industry between 60 and 80 °C using heat pump technology with an economically viable heat output factor of well over 2, ideally above 3 to 5, and to utilize them as high-quality process heat at a consistently high temperature level of over 200 °C, a temperature increase of at least 120 to 140 Kelvin would be necessary. A heat pump technology that enables such a heat pump cycle is not yet available.

[0039] From DE 10 2013 008 080 A1 an arrangement for a cold-heat coupling with a refrigeration circuit and a heat pump circuit as two left-handed cold vapor processes is known, which are thermally connected to each other via a common intermediate pressure tank, wherein the refrigeration circuit has an evaporator for evaporating a refrigerant and thus generating a cooling capacity, a refrigeration compressor and a throttle valve and the heat pump circuit has a heat pump compressor for increasing the pressure of the refrigerant vapor, a condenser for condensing the refrigerant and a heat pump Throttle valve to reduce the pressure of the refrigerant to intermediate pressure level.

[0040] US 2012 / 0116594 A1 discloses a pumping system for temperature management which uses a supersonic ejector instead of a conventional compressor. In this system, a stream coming from the evaporator is mixed with a portion of a stream from a compressor in the ejector and passed into a separator. Another stream downstream of the compressor is condensed in a condenser and expanded through an expansion valve to the intermediate conditions of the separator. A liquid phase of the separator expands through an expansion valve to the conditions of the evaporator, at the outlet of which the vapor is sucked in by the ejector.

[0041] EP 2 317 251 A1 describes a two-stage compression heat pump cycle device with NH3 as the heat transfer medium. On the downstream side of an oil separator, a condenser is arranged, followed by a first cooling device which is connected to an intercooler. The liquid phase from the intercooler is passed to a second cooling device and an evaporator, and returned to the intercooler via a lower stage compressor. The vapor phase from the intercooler passes into a high-stage compressor connected to the oil separator in order to separate the oil portion contained in the gaseous heat transfer medium from the lubricating oil used for the high-stage compressor. The separated lubricating oil is fed via a return line to the gas inlet side of the high-stage compressor or the lower-stage compressor.

[0042] CN 1 13 251 698 A concerns a multi-stage Compression heat pump system for the recovery of waste heat in power plants with a high-pressure compressor, a medium-pressure compressor, and a low-pressure compressor. On the low-pressure stage, an evaporator and a gas-liquid separator are arranged upstream of the low-pressure compressor, which feeds into a first intercooler. An outlet of the first intercooler is connected to the medium-pressure compressor, which in turn feeds into a second intercooler. From the second intercooler, the outlet is fed into a condenser via the high-pressure compressor and then gradually recirculated via the condenser's outlet and an intermediate liquid storage tank via throttle valves in each of the individual pressure stages.

[0043] The object of the invention is to improve the state of the art.

[0044] The object is achieved by a heat pump device for energy-efficient generation of process heat, wherein the heat pump device has a heat-absorbing side, a heat-emitting side, a cycle fluid and an evaporator on the heat-absorbing side, and at least one heat exchanger and at least one heat sink on the heat-emitting side and at least one heat source on the heat-absorbing side can be assigned to the heat pump device, wherein by means of the Evaporator's liquid cycle fluid can be indirectly heated by heat supply from the assignable heat source and evaporated at a pressure stage of the evaporator, and the heat pump device has at least one first compressor downstream of the evaporator, wherein by means of the at least first compressor, vaporous cycle fluid can be compressed from the pressure stage of the evaporator to a second pressure stage, and the heat pump device has at least one first mixing separator in the second pressure stage, wherein the at least first mixing separator has a first connection for the inlet of vaporous cycle fluid, a second connection for the inlet of condensed cycle fluid, a third connection for the outlet of vaporous cycle fluid and optionally a fourth connection for the outlet of condensed cycle fluid and at least one second compressor is downstream of the mixing separator,so that vaporous cycle fluid emerging from the third connection can be compressed in the at least second compressor from the second pressure stage to a first pressure stage and by means of the at least one associated heat exchanger, process heat can be indirectly transferred from the vaporous cycle fluid of the first pressure stage to the at least one assignable heat sink and that cycle fluid condensed in the at least one heat exchanger can be returned via the second connection into the at least first mixing separator of the second pressure stage, wherein at the same time vaporous cycle fluid from the at least first compressor via the first connection into the mixing separator, can be introduced, wherein the at least first mixing separator has the fourth connection for the outlet of condensed cycle fluid, so that the escaping condensed cycle fluid can be returned directly or indirectly to the evaporator and / or fed to the at least second compressor.

[0045] Thus, a high-temperature heat pump is provided in which, when the at least one mixing separator is arranged in the second pressure stage, process heat can be released in a temperature range of approximately 100 °C to 250 °C on the heat-emitting side by means of the at least one heat exchanger of the first pressure stage.

[0046] For this purpose, the fourth connection of the at least first mixing separator can be connected directly or indirectly to the evaporator and / or the at least second compressor by means of at least one pipe.

[0047] It is particularly advantageous that the heat pump device can be operated, particularly preferably, with water as a natural and completely environmentally friendly circulating process fluid.

[0048] Water is liquid under standard conditions and has the advantage of a high critical pressure of 221.2 bar and a high critical temperature of 374.15°C, whereby in the two-phase region, for example at a comparatively low pressure of 16 bar and at a condensation temperature of over 201°C, a high condensation enthalpy of 1,933 kJ / kg can be used for heat transfer to a heat sink, while in comparison the specific Condensation enthalpy of NH3 at only 100°C and already 62.55 bar is only 715.7 kJ / kg.

[0049] Thus, a heat pump device is provided with a heat pump cycle process which is based on a cycle process with at least three pressure stages with different pressure levels, with - at least one first pressure stage with a pressure of the vaporous cycle fluid which corresponds to the highest condensation pressure of the cycle fluid in the cycle on its heat-emitting side, so that the condensation temperature of the cycle fluid is so far above the highest required sink temperature of the highest-value heat sink to be supplied that this is sufficient for heat transfer from the condensing cycle fluid to the highest-value heat sink, - and at least one second pressure stage in which the at least one mixing separator is arranged and which has a pressure of the vaporous cycle fluid which is lower than that of the first pressure stage and higher than the evaporation pressure of the cycle fluid in the evaporator, and - at least one lowest pressure stage with a pressure of the vaporous cycle fluid corresponding to the evaporation pressure in the evaporator, which corresponds to the lowest condensation pressure of the cycle fluid within the cycle of the heat pump device.

[0050] A key idea of ​​the invention is that a reduction in the destruction of specific exergy occurs during the total specific compressor work applied, based on the specific usable process heat, at the temperature level of the respective highest required sink temperature. This is achieved by successive enthalpy utilization of condensed cycle fluid, after its condensation enthalpy at the condensation pressure of a first pressure stage has been utilized as process heat for a heat sink of the highest required sink temperature and the enthalpy contained in the condensed cycle fluid of this first pressure stage is partially fed to the vaporous cycle fluid of at least a second pressure stage in at least one mixing separator in the compression train.When the condensed cycle fluid from the first pressure stage, which has a temperature approximately equal to the condensation temperature of the condensed cycle fluid, passes into the at least one mixing separator of a second, i.e. lower, pressure stage with a lower condensation temperature, the liquid cycle fluid cools down to the condensation temperature of the lower pressure stage and part of its enthalpy is used to evaporate part of the liquid cycle fluid. This evaporated portion is fed to the already vaporous flow of cycle fluid in the compression train at this lower pressure stage without compressor work, whereby the condensation enthalpy of the vaporous cycle fluid available at this pressure stage is increased, whilst the enthalpy of the cycle fluid available up to this pressure stage is reduced. The required compressor work remains constant. This increases the heat output and boosts energy efficiency.

[0051] The following terminology is explained:

[0052] A "heat pump device" is, in particular, a machine which, by expending technical work, absorbs thermal energy from a reservoir and / or a low-temperature heat source and, together with drive energy, transfers it as useful heat to a system to be heated and / or a higher-temperature heat sink. A heat pump device is, in particular, configured to carry out a heat pump cycle on a cycle fluid with the aim of transferring process heat to a heat sink by absorbing heat from an available low-temperature heat source and upgrading the absorbed heat by increasing the temperature by means of mechanical work to at least one of the highest required sink temperatures for the heat sink.

[0053] A "heat pump cycle" is in particular a cycle process in which a closed quantity of a cycle fluid is evaporated, in particular by supplying heat from a reservoir and / or a heat source at a low pressure, then vaporous cycle fluid is produced, in particular by performing mechanical work or by other processes, such as mixing with vaporous cycle fluid of a higher pressure in a Mixing separator, or a combination thereof, is compressed to a high pressure and in the process assumes a higher temperature, is then at least cooled or condensed by heat extraction from a heat sink at this high pressure and is then brought back to a low pressure before evaporation at least by throttling or heat extraction.

[0054] A "fluid cycle" is in particular a fluid which, under certain physical conditions, is either liquid, gaseous or both at the same time, the latter being referred to as a so-called two-phase state, which is represented in phase diagrams within the so-called two-phase region between the boiling line and the condensation line, or is supercritical, which describes conditions outside the two-phase region, i.e. either a pressure higher than the critical pressure of the fluid or a temperature higher than the critical temperature of the fluid.In addition, a quantity of liquid or vaporous cycle fluid can be withdrawn from the cycle per unit of time at any pressure level for other thermal or material utilization, and the same quantity of liquid or vaporous cycle fluid can be simultaneously fed back into the cycle at another point in the same unit of time. This can, for example, be vaporous cycle fluid that is used as a heating medium or motive steam for an external process and, for example, in liquid form elsewhere. Condensed cycle fluid is fed back into the cycle. A withdrawal point can also be implemented at which cycle fluid is withdrawn, particularly sporadically or continuously, for cleaning purposes, and cleaned cycle fluid is fed back into the cycle at another feed point in order to monitor and / or adjust the quality of the cycle fluid and its fill level within the heat pump device.

[0055] A "process heat" is in particular heat transferred by means of at least one heat exchanger of the first pressure stage to a heat sink or by means of another heat exchanger of a further pressure stage to a further heat sink.

[0056] A "heat sink" is in particular a reservoir and / or a flow with an inlet and an outlet of a fluid or heat transfer medium, the temperature of which is to be raised from an inlet temperature of the inlet to an outlet temperature of the outlet, wherein the target temperature to be achieved for the outlet temperature of the heat sink is the "highest required sink temperature" of a heat sink. A heat sink can be a heat transfer medium which is heated for the purpose of heating another fluid and / or material flow, in particular in an external device outside the heat pump device, so that, for example, in a heat exchanger, a heat transfer medium is heated which is used to heat an external process in another device, for example a Dryer or its auxiliary media or the material being dried. The heat sink can also be a process gas stream that is heated in a drying device to dry a moist material, so that a drying process is then carried out with the process gas stream, in which the heated process gas transfers heat to a moist material and thus to a material being dried, evaporates the moisture contained therein, and possibly also removes it from the material being dried.

[0057] A "heat source" is in particular a reservoir whose temperature can be used to transfer heat and / or waste heat to a cyclic process fluid. A heat source can also be a flow with an inlet and an outlet of a fluid or heat transfer medium, the temperature of which can be reduced from a highest available temperature, i.e. the lowest available source temperature, from an inlet temperature of the inlet to an outlet temperature of the outlet, whereby in particular a target temperature for the heat transfer in an evaporator is the "lowest possible source temperature" of the outlet of a heat source.A heat source can also be a waste heat stream used to heat the evaporator of the heat pump device in order to supply the cycle with sufficient heat at a low pressure level of the cycle fluid so that sufficient process heat can be provided in at least one heat exchanger. Likewise, a heat source can be a process gas stream coming from a drying device after drying a moist material, i.e. waste heat, and the heat content of the process gas stream is used for heat recovery via a heat exchanger of the heat source in order to heat the evaporator of the heat pump device, wherein drying devices can often have a high heat loss via a process gas stream that exits a drying device after drying a moist material and generally amounts to approximately the level of the process heat requirement of the drying system, but is regularly available at a significantly lower temperature level and can therefore possibly be used to heat the evaporator of the heat pump device. A heat source can also be a heat-emitting side, for example waste heat, of a refrigeration system used to generate process cooling, the heat emitted from this is used to heat the evaporator of the heat pump device.A heat source can also be a heat-emitting side of a refrigeration system or heat pump used to generate process cooling, the heat emitted by which is used in a heat exchanger of the heat source to indirectly heat the evaporator of the heat pump device. In refrigeration systems that frequently operate intermittently and are therefore subject to fluctuations in heat emission, a heat supply that is as constant as possible can be provided to heat the evaporator of the heat pump device, particularly for compensation. Such compensation can be realized in particular in the form of a combination of various waste heat streams, for example waste heat from. a process gas stream in combination with waste heat from a refrigeration system or heat pump or with other waste heat.

[0058] "Waste heat" is particularly defined as a heat source whose heat is available at such a low temperature level that, particularly in the vicinity of the heat source, there is no heat sink with a lower, highest required sink temperature for the use of this heat as process heat or if this heat could only be used as process heat at an expense that is no longer economically justifiable.

[0059] A "heating performance figure" with the abbreviation COPh (from the English "Coef ficient of Performance - heat") is in particular the quotient of usable process heat per unit of time related to the mechanical work expended per unit of time and represents a key figure for the energy efficiency of the generation of process heat, particularly for a heat pump device.

[0060] A "heat exchanger" is in particular a device in which thermal energy, i.e. heat, is transferred from one material flow of higher temperature to another material flow of lower temperature, wherein the material flows are spatially and materially separated from each other by a wall of the heat exchanger. Preferably, a heat exchanger is an indirect heat exchanger. One of the material flows flowing through a heat exchanger can be, for example, the cyclic process fluid or an inlet or outlet of a The heat pump device can also be a fluid or heat transfer medium of a heat sink or heat source. The heat pump device can also have two or more heat exchangers on the heat-absorbing side and / or the heat-emitting side.

[0061] An "evaporator" is in particular a device or apparatus in which a liquid cyclic process fluid changes its state from liquid to gaseous, in particular through indirect heat transfer from a heat source, and thus undergoes a "phase transition" from liquid to gaseous, wherein the gaseous state of a cyclic process fluid is generally referred to as "vapor" and the state as "vaporous" if it is a cyclic process in which at least one phase transition between two states takes place, whereas a gaseous state indicates that no phase transition takes place. An evaporator is in particular arranged in the lowest and / or lowest pressure stage of the cyclic process.

[0062] A "compressor" (also called compressor) is in particular a device or apparatus for compressing and / or increasing the pressure of a compressible fluid, for example a vaporous cycle fluid, in particular with the aim of achieving a higher pressure level in order to thereby raise the condensation temperature of the vaporous cycle fluid. This is also referred to as "upgrading" the heat content of the vaporous cycle fluid for use as "higher-quality" process heat. A compressor is particularly designed as a turbomachine, such as an axial fan, a radial fan, a turbocompressor, or a turbine. A compressor can also be designed as a positive-displacement machine, such as a piston compressor, a rotary piston compressor, or a screw compressor.A compressor can be a thermal compressor, such as a vacuum steam jet pump, in which vaporous cycle fluid from a second or first pressure stage is used as motive steam, which reaches high speeds in the thermal compressor and thereby sucks in suction steam in the form of vaporous cycle fluid at a pressure lower than that of the motive steam, with the motive steam and suction steam then mixing to form a mixed steam with the pressure of a pressure stage that has a higher pressure than the suction steam and a lower pressure than the motive steam.

[0063] A "compression train" is in particular a sequence of compression processes of vaporous cycle fluid in at least two compressors connected directly or indirectly in series, regardless of the design, with the aim of compressing the vaporous cycle fluid from at least one lower pressure stage to at least one higher pressure stage.

[0064] “Overheating” is particularly a State condition of a vaporous cycle fluid whose temperature is above the Condensation temperature, which correlates with the prevailing pressure and / or pressure level and is broadly simplified as a temperature difference in Kelvin. In contrast, the degree of superheat is correctly understood as the difference between the specific enthalpy of the vaporous cycle fluid and the specific saturated steam enthalpy in kJ / kg at the prevailing pressure.

[0065] A "pressure stage" is to be understood in particular as a synonym for a total pressure achieved at the outlet of a compressor, regardless of the design, after compression of vaporous cycle fluid to specifically indicate that a heat pump device involves a step-by-step compression of vaporous cycle fluid. This is accompanied by the corresponding boiling and condensation temperature of the cycle fluid at the pressure of this pressure stage.

[0066] A "first pressure stage" is to be understood in particular as the pressure stage with the highest condensation pressure of the cycle fluid within the heat pump device, which is required in order to be able to supply the heat sink with the highest required sink temperature with process heat by condensation, for example in a pressure range between approximately 1 bar for process heat of approximately 100°C to approximately 40 bar for process heat of approximately 250°C.

[0067] A "pressure level of an evaporator" is to be understood in particular as the pressure level at which an evaporator of the heat pump device is operated in order to evaporate liquid cycle fluid with heat supplied from a heat source. evaporate, for example in a pressure range between about 40 hPa at a lowest source temperature of about 30 ° C to about 1.4 bar at a lowest source temperature of about 110 ° C .

[0068] A "second pressure stage" is to be understood in particular as a pressure stage below a first pressure stage and above the pressure stage of an evaporator. In the second pressure stage, in particular, the at least one mixing separator is arranged.

[0069] A "third pressure stage" is to be understood in particular as a pressure stage below a second pressure stage and above the pressure stage of an evaporator. A "fourth pressure stage" is to be understood in particular as a pressure stage below a third pressure stage and above the pressure stage of an evaporator. A "fifth, sixth, seventh and optionally further pressure stage" is to be understood in particular analogously. The designation of the pressure stages serves in particular to distinguish the respective existing pressure and does not represent a fixed order.

[0070] A "mixing separator" is in particular a device which is assigned to a specific pressure stage with a pressure above the pressure stage of an evaporator and less than and / or equal to the first pressure stage, wherein a mixing separator encloses a volume and has at least one connection for the inlet for vaporous cycle fluid of the assigned pressure stage, one connection for the inlet for liquid cycle fluid and one connection for the outlet for vaporous Cycle fluid of the assigned pressure stage. An essential function of a mixing separator is, in particular, the saturation of a flow of vaporous, superheated cycle fluid after compression by mixing with liquid cycle fluid. Another function of a mixing separator can also be the expansion and spontaneous evaporation of liquid cycle fluid, for example from a higher pressure stage, if its temperature is higher than the correlating condensation temperature of the assigned pressure stage of the mixing separator.

[0071] According to the invention, the at least first mixing separator has the fourth connection for the outlet of condensed cycle fluid, so that the escaping condensed cycle fluid can be returned directly or indirectly to the evaporator and / or fed to the at least second compressor.

[0072] As a result, at least the first mixing separator can have the connection for the outlet for liquid cycle fluid of the pressure stage assigned to the mixing separator, through which excess liquid cycle fluid possibly exits, which is not required or consumed to saturate vaporous cycle fluid entering the mixing separator superheated at a connection for the inlet, or which does not evaporate by spontaneous evaporation upon entry into the mixing separator, and which then exits from the mixing separator at the corresponding condensation temperature of the relevant assigned pressure stage of the mixing separator.

[0073] The liquid cycle fluid emerging from at least the first mixing separator can be returned to the evaporator via a condensate separator. A partial flow of the liquid cycle fluid can also be fed to the second compressor via a condensate pump and / or a control valve. As a result, the liquid cycle fluid emerging from at least the first mixing separator can be used to generate wet steam.

[0074] In order to provide an interface to at least one heat sink, the heat pump device has at least one heat exchanger assigned to the first pressure stage and / or one heat exchanger assigned to the second pressure stage and / or one heat exchanger assigned below the second pressure stage on the heat-emitting side.

[0075] In a further embodiment, the heat pump device may comprise at least one heat source and / or at least one heat sink.

[0076] In order to provide an adaptable multi-stage, modular structure and to realize a subdivision of the compression, the heat pump device has a second mixing separator, a third mixing separator, a fourth mixing separator and / or optionally further mixing separators, wherein a further compressor is connected upstream of the respective mixing separator.

[0077] Thus, two or more mixing separators can be arranged between the evaporator and the first pressure stage, in particular connected in series.

[0078] Through a multi-stage structure and the division of the compression of the vaporous cycle fluid into several compression steps at individual pressure stages, i.e. from the lowest pressure of the cycle of one pressure stage in an evaporator to the highest required pressure of the first pressure stage, which build on one another, the desired temperature difference between the lowest available heat source and / or waste heat temperature and the highest required sink temperature can be configured very variably. This reduces the pressure ratio required per compression step, i.e. the quotient of the achieved compression pressure related to the inlet pressure before compression, whereby the superheating of the compressed cycle fluid, conventionally expressed in Kelvin above the condensation temperature at the achieved compression pressure, is significantly lower than with single-stage compression from the lowest to the highest pressure in the cycle.This allows for very high final pressures to be achieved, which, depending on the choice of cyclic process fluid and the location of its critical point and two-phase region, enable correspondingly high condensation temperatures and condensation enthalpies for the transfer of process heat to a heat sink. Thus, especially with water as the cyclic process fluid, condensation conditions ranging from as little as 40 bar up to approximately 250 °C are possible.

[0079] Due to the variably scalable heat pump device and the widely configurable structure of the heat pump device, the area of ​​application can be extended to a temperature level of up to 250 ° C with a temperature lift of approximately 200 Kelvin at heating output coefficients of over 2.5, while maintaining the use of waste heat with temperatures below 60 ° C to 80 ° C for the generation of process heat, whereby process heat can also be released simultaneously at several different temperature levels between, for example, 100 ° C and 250 ° C.

[0080] This multi-stage design is advantageous for several reasons. First, it reduces superheating during compression. While this does not represent a thermal advantage, it can eliminate the need for lubrication of pistons or other sliding surfaces of displacement bodies, for example in high-pressure compressors based on the displacement principle. This allows for an oil-free compressor design and a simplified construction, as well as expanding the application area to include hygienic steam.

[0081] On the other hand, branches can be created in the cycle, which enables the use of process heat at different temperature levels, by not only generating the highest-value process heat for the highest required sink temperature, but also by specifically supplying heat sinks with a lower required sink temperature with process heat generated for them at a lower condensation temperature of the cycle fluid on a second, third, fourth, and / or further pressure stages. This reduces the overall destruction of specific exergy, since less specific compression work is required for lower-value process heat than for higher-value process heat. A design with more than three pressure stages and separate generation of process heat of different values ​​at different temperature levels increases the overall heating performance factor of the heat pump process.

[0082] This allows the production of nearly saturated steam from a highest pressure stage by introducing liquid cyclic fluid from a lower pressure stage, either upstream of the highest compressor, so that it operates as a wet steam compressor, or downstream of the highest compressor, e.g., if another mixing separator follows the highest pressure stage. In this case, a liquid condensate from any of the lower pressure stages (and thus not just from the lowest stage above the evaporator) can be used to saturate the compressed steam from the highest pressure stage.

[0083] In a further embodiment of the heat pump device, a mixing separator or two or more mixing separators are connected upstream of the first mixing separator, wherein the vaporous cycle fluid of the respective upstream mixing separator can be fed to the subsequent mixing separator via a respective downstream compressor and / or the liquid cycle fluid from the respective downstream mixing separator at a higher pressure and / or a higher temperature than in the upstream mixing separator.

[0084] This provides a heat pump device in which vaporous cycle fluid of at least a second, third, fourth and / or further pressure stage condenses in at least one heat exchanger of at least a second heat sink and indirectly transfers heat to the latter, wherein a cycle fluid condensed at this second, third, fourth and / or further pressure stage in the heat exchanger of a second or further heat sink enters a mixing separator of a respectively lower pressure stage, i.e. a third, fourth, fifth and / or further pressure stage, at a pressure below that of the cycle fluid condensing in the heat exchanger.

[0085] Thus, by means of the heat pump device, an extended heat pump cycle process is made possible, which is based on a cycle process with at least four pressure stages with different pressures, i.e. at least a first, at least a second, at least a third pressure stage and at least one lowest pressure stage of the heat pump cycle process on the pressure of an evaporator, wherein the heat pump device is easily scalable and variably configurable by adding further pressure stages, i.e. a fourth, fifth, sixth and / or subsequent pressure stage with corresponding mixing separators and compressors, in order to adjust the total achievable temperature rise as required.

[0086] In a heat pump device with staged compression, the vaporous cycle fluid from a mixing separator of one pressure stage is compressed to a higher pressure stage in each compression step and is superheated due to polytropic compression. The superheat, which occurs after compression and subsequently in the vaporous cycle fluid before it enters a mixing separator assigned to a pressure stage, is used to proportionally evaporate liquid cycle fluid, which enters via a connection for the entry into the respective mixing separator of the pressure stage reached by upstream compression.This evaporated portion is added to the already vaporous flow of cycle fluid in the compression train at this pressure level without compressor work, thereby increasing the total condensation enthalpy of the vaporous cycle fluid available later as process heat at this pressure level, while the compressor work remains constant until then. This increases the heat output coefficient.

[0087] A further advantage of the heat pump device with step-wise compression is the use of cycle fluid to reduce the overheating that occurs due to compression, since the cycle fluid itself has already been treated or at least decalcified once for the initial filling of the heat pump device and because the closed cycle process is reused, which completely avoids continuous water consumption through the injection of tap water or other calcareous water as well as the unavoidable limescale deposits that result from this compared to the state of the art.

[0088] A further advantage of the heat pump device with staged compression is the staged cooling of the condensed cycle fluid to complete the cycle by expansion at each lower pressure stage, fully utilizing the enthalpy contained therein. The enthalpy is added to the steam mass flow of the respective lower pressure stage as an additional saturated steam component for the additional evaporation of the liquid cycle fluid without compressor work. This further increases the heat output coefficient.

[0089] A further advantage of the heat pump device with gradual cooling of condensed cycle fluid in individual pressure stages is the significantly increasing amount of vaporous cycle fluid during the gradual compression in the compression train along the pressure increase, whereby considerably less liquid cycle fluid has to be evaporated in the evaporator than has to be provided for heating heat sinks for condensation. As a result, only a significantly lower mass flow of vaporous cycle fluid has to be transported through the evaporator and compressed successively in the compressors of the lower pressure stages of the compressor train, which Due to the large specific volume of the vaporous cycle fluid at low pressure, these typically have the largest sizes. This significantly reduces the size of these devices without compromising performance.

[0090] In order to improve the return of the cycle fluid condensed in at least one heat exchanger from the first and / or further pressure stage, a condensate separator is or are connected downstream of the at least one heat exchanger and / or a condensate separator is or are connected downstream of the second heat exchanger and / or a condensate separator is or are connected downstream of the further heat exchangers for returning condensed cycle fluid from the first pressure stage to the first mixing separator and / or condensed cycle fluid from the second or a third pressure stage to an upstream mixing condenser, in particular a lower pressure stage.

[0091] In a further embodiment of the heat pump device, a condensate separator for returning the condensed cycle fluid to the respective upstream mixing separator or to the evaporator is or are arranged after the fourth connection for the outlet of condensed cycle fluid of the first mixing separator, an upstream mixing separator and / or the respective mixing separator.

[0092] To generate mixed steam of a pressure level and to Suction steam from a lower pressure stage or the pressure level of the evaporator is the first Compressor designed as a thermal compressor, so that by means of the thermal compressor the vaporous cycle fluid of the first pressure stage can be mixed as motive steam with the vaporous cycle fluid from the evaporator as suction steam and can be fed as compressed mixed steam to the first mixing separator or the first upstream mixing separator.

[0093] Accordingly, a compressor upstream of the mixing separator of the respective pressure stage is designed as a thermal compressor, so that by means of the thermal compressor the vaporous cycle fluid of a higher pressure stage can be mixed as motive steam with the vaporous cycle fluid of a lower pressure stage as suction steam and can be fed to the mixing separator of this pressure stage as compressed mixed steam.

[0094] In the thermal compressor, in particular a stream or partial stream of vaporous cycle fluid from a first or a further pressure stage can be used as motive steam, which reaches high speeds in the thermal compressor and thereby sucks in suction steam in the form of vaporous cycle fluid with a pressure lower than that of the motive steam due to Venturi or Coanda effects, wherein the motive steam and suction steam then mix to form a mixed steam with a pressure of a pressure stage which is higher than the pressure of the suction steam and lower than the pressure of the motive steam.

[0095] In a further embodiment of the heat pump device, a further compressor in the first pressure stage or the second pressure stage or a further pressure stage is arranged upstream of the thermal compressor, so that the compressed vaporous cycle fluid, in particular the vaporous cycle fluid originating from the first pressure stage and further compressed to the pressure of a motive steam pressure stage, can be used as motive steam.

[0096] In order to realize wet vapor compression or dry compression, a further mixing separator is arranged downstream of the first mixing separator in the second pressure stage, with the further mixing separator being arranged in the first pressure stage.

[0097] The downstream mixing separator in the first pressure stage can have a downstream compressor or it can be free of a compressor

[0098] In a further embodiment, the heat pump device has a control and / or regulating device for controlling and / or regulating components of the heat pump device and optionally the at least one heat source and / or the at least one heat sink.

[0099] This allows the control and / or regulation of the heat pump device and its process heat supply with regard to the highest possible energy efficiency due to the lowest possible drive power by controlling pressures and temperatures of individual pressure stages by controlling compressors and controlling the heating power of the Heat source and control of flow rates in the condensed cycle fluid at the inlet to individual mixing separators and / or compressors. Thus, at least one sub-process contained in or connected to the heat pump device, or even the entire process of the heat pump device, can be monitored and controlled by at least one control and / or regulating device.

[0100] In order to return the condensed cycle fluid in the form of droplets to the respective mixing separator, the second connection for the inlet of condensed cycle fluid has a spraying device for spraying the liquid cycle fluid entering the first mixing separator or the respective mixing separator.

[0101] A spraying device can, for example, be a spray nozzle. This sprays the incoming liquid cycle fluid into the mixing separator in the form of droplets, creating a pressure loss. A portion of the liquid cycle fluid entering the second connection evaporates depending on its temperature, thus reducing overheating of the vaporous cycle fluid entering the first connection.

[0102] In a further aspect of the invention, the object is achieved by a drying device for drying a material to be dried by means of a heated process gas stream, wherein the drying device comprises a heat pump device as described above, so that on the The process gas stream can be heated as a heat sink on the heat-emitting side of the heat pump device.

[0103] Thus, process heat at a high temperature level of up to 250°C can be used to heat a process gas stream of the drying device.

[0104] In an additional aspect of the invention, the object is achieved by a method for operating a heat pump device for energy-efficient generation of process heat, in particular in a temperature range between 100 °C and 250 °C, by means of a previously described heat pump device, comprising the following steps: - Heating a liquid cycle fluid by indirect heat supply from a heat source and evaporating the liquid cycle fluid in an evaporator at a pressure level of the evaporator, - compressing the vaporous cycle fluid by means of a first compressor to a second pressure stage, - Supplying the compressed vaporous Cycle fluids in at least one mixing separator of a second pressure stage, - feeding the vaporous cycle fluid emerging from the at least one mixing separator into at least one second compressor and compressing the vaporous cycle fluid from the second pressure stage to a first pressure stage, - Transferring process heat from the compressed, vaporous cycle fluid of the first pressure stage to at least one assignable heat sink, - and optionally returning the condensed cycle fluid from the first pressure stage to the at least one mixing separator.

[0105] In a further embodiment of the process, fluid water, an alcohol and / or a water-soluble organic substance is or are used as a cyclic process.

[0106] Preferably, the heat pump device is operated with water (chemical formula H2O) as a natural and completely environmentally friendly cyclic process fluid. Likewise, the heat pump device can also be operated with an alcohol and / or an aqueous solution of an alcohol as a cyclic process fluid. Likewise, an aqueous solution of a water-soluble organic substance and / or one or more organic substances can be used as a cyclic process fluid. Likewise, any combination of water, alcohol and / or water-soluble organic substance can be used as a cyclic process fluid.

[0107] For example, methanol, ethanol or propanol can be used as alcohol and an ester and / or an ether can be used as organic substance.

[0108] In a further embodiment of the process, in a stream of the condensed Cyclical process fluids, in particular at a pressure level higher than the pressure level of the evaporator, a pressure increase can be carried out by means of a condensate pump, then this stream can be mixed with a stream of liquid cyclic process fluids, which was previously indirectly heated in a heat exchanger of a heat source, and the mixed streams can be used for the indirect heating of the evaporator, before in particular the mixed stream is returned to the evaporator.

[0109] In a further embodiment of the method, a pressure increase is carried out in a stream of the condensed cycle fluid emerging from the at least one mixing separator by means of at least one condensate pump, and finally this stream is introduced into vaporous cycle fluid from the at least one mixing separator to generate cycle fluid wet steam, before the cycle fluid wet steam is compressed to the first pressure stage in the downstream compressor.

[0110] The invention will be explained below using exemplary embodiments. Figure 1 is a highly schematic representation of a Heat pump device with an evaporator, a first compressor, a mixing separator of a second pressure stage, a second compressor and a heat exchanger of a first pressure stage, Figure 2 is a highly schematic representation of a Alternative of the heat pump device shown in Fig. 1 with heating of an evaporator via a circuit by a heat exchanger of a heat source, Figure 3 is a highly schematic representation of a Alternative of the heat pump device shown in Fig. 2 with an additional mixing separator after compression to a first pressure stage, Figure 4 is a highly schematic representation of a Alternative of the heat pump device shown in Figure 3 and a thermal compressor supplied with motive steam from a first pressure stage for compressing vaporous Cycle fluid from the pressure stage of the evaporator to a second pressure stage, Figure 5 is a highly schematic representation of a Alternative of the heat pump device shown in Fig. 4 and a thermal compressor supplied with motive steam from a motive steam pressure stage for compressing vaporous Cycle fluid from the pressure stage of the evaporator to a second pressure stage, Figure 6 is a highly schematic representation of another alternative to the one shown in Fig. 3 Heat pump device with an additional third pressure stage, Figure 7 is a highly schematic representation of a Alternative of the heat pump device shown in Fig. 6 with an additional transfer of process heat of a second pressure stage in a heat exchanger of a second heat sink, Figure 8 is a highly schematic representation of a further alternative of the heat pump device shown in Fig. 6 with an additional fourth pressure stage, Figure 9 is a highly schematic representation of a Alternative to the heat pump device shown in Fig. 8 with a thermal compressor supplied with motive steam from a motive steam pressure stage for compressing vaporous Cycle fluid from the pressure stage of the evaporator to a fourth pressure stage, Figure 10 is a highly schematic representation of a further alternative of the heat pump device shown in Fig. 8 with an additional transfer of process heat of a second pressure stage in a heat exchanger of a second heat sink, Figure 11 is a highly schematic representation of a Alternative of the heat pump device shown in Fig. 10 with a transfer of process heat of a third instead of a second pressure stage in a heat exchanger of a second heat sink, and Figure 12 is a schematic representation of a Mixing separator of a Heat pump device.

[0111] A heat pump device 1 shown in Figure 1 has an evaporator 200 with heating via an inlet 14 and an outlet 15 of a heat source, a compressor 401 from the pressure stage of the evaporator 200 to a second pressure stage, a mixing separator 400 of a second pressure stage, a compressor 501 from a second to a first pressure stage, a heat exchanger 520 of a first heat sink for transferring process heat of a first pressure stage and an inlet 10 and an outlet 11 of a dryer device 5 as a heat sink. The heat pump device 1 has a control and regulation unit 2 for controlling and regulating the functions and components of the heat pump device 1.

[0112] The mixing separator 400 of the second pressure stage has a connection 406 for the inlet of vaporous cycle fluid, a connection 407 for the inlet of liquid cycle fluid, a connection 408 for the outlet 408 of vaporous cycle fluid and a connection 409 for the outlet of liquid Cycle fluid on. In the connection 407 for the inlet of liquid cycle fluid, a spraying device for spraying the liquid cycle fluid is integrated in order to spray the incoming liquid cycle fluid in the form of droplets into the mixing separator 400, building up a pressure loss, wherein a portion of the liquid cycle fluid entering at connection 407 evaporates depending on its temperature and in the process, overheating of the vaporous cycle fluid entering at connection 406 is reduced.

[0113] At the lowest pressure of the cycle in the evaporator 200, usually a partial vacuum below atmospheric pressure, and at the same time at the lowest temperatures of the cycle, liquid cycle fluid returned from a mixing separator 400 of the second pressure stage is heated by a heat source via inlet 14 and outlet 15 and evaporated, and then vaporous cycle fluid is compressed as dry vapor from the pressure stage of the evaporator in a compressor 401 to a second pressure stage and enters the mixing separator 400 of the second pressure stage in a superheated state.

[0114] Vaporous cycle fluid emerges from the mixing separator 400 as dry steam of a second pressure stage and is supersaturated with injected condensate and thus liquid cycle fluid via a condensate pump 250 before being compressed in a compressor 501 and thereby converted into wet steam with a proportion of liquid cycle fluid, that during the subsequent compression to a first pressure stage in the compressor 501, this liquid portion evaporates and dry-saturated vaporous cycle fluid of a first pressure stage exits the compressor 501. In a heat exchanger 520 of a heat sink, process heat at the condensation temperature of a first pressure stage is transferred from the vaporous cycle fluid to the heat sink with an inlet 10 and an outlet 11, wherein the cycle fluid condenses. Liquid cycle fluid exits the heat exchanger 520 at approximately condensation temperature and at a first pressure stage via a condensate separator 522 and is introduced into the mixing separator 400 of the second pressure stage, wherein it expands at its second pressure stage and cools down to its condensation temperature of the second pressure stage.In this case, a portion of the cycle fluid introduced in liquid form from the heat exchanger 520 evaporates and forms vaporous cycle fluid on the second pressure stage. A further portion of the cycle fluid introduced in liquid form from the heat exchanger 520 evaporates due to the degree of superheating of the vaporous cycle fluid entering the mixing separator 400 from the compressor 401. The remaining portion of the cycle fluid introduced in liquid form from the heat exchanger 520 into the mixing separator 400 is considered excess liquid cycle fluid and exits the mixing separator 400 at the pressure and condensation temperature of the second pressure stage before being fed back into the evaporator 200.

[0115] In an alternative shown in Figure 2, a heat pump device 1 has indirect heating of the evaporator 200 via a circuit through a heat exchanger 220 of a heat source (14, 15), wherein, in contrast to the illustration in Figure 1, a flow of condensed cycle fluid from a mixing separator 400 of a second pressure stage is introduced into a flow of liquid cycle fluid, which was previously indirectly heated in the heat exchanger 220 of the heat source, and the mixture of both flows is used to indirectly heat an evaporator 200. To overcome a pressure difference from the outlet from the second pressure stage to the circuit with a circulation pump 222, a condensate pump 201 is used.

[0116] Furthermore, the heat pump device 1 shown in Figure 2, in contrast to the representation in Figure 1, is designed to introduce a cycle fluid condensed at a second pressure stage from a mixing separator 400 of a second pressure stage into vaporous cycle fluid from a second pressure stage to generate cycle fluid wet steam, before this wet steam is compressed in a compressor 501 to a first pressure stage. In this case, a condensate pump 201 conveys the amount of condensed cycle fluid which emerges from the mixing condenser 400 of the next higher pressure stage above the pressure stage of the evaporator 200. At the same time, a condensate pump 201 provides a sufficient injection pressure of liquid cycle fluid of a second pressure stage before a compression 501 to a first pressure stage is ready. Otherwise, the heat pump device 1 shown in Figure 2 is operated as described above.

[0117] An alternative of a heat pump device 1 shown in Figure 3, in contrast to the representation in Figure 2, has that vaporous cycle fluid after a compression 501 from a second pressure stage to a first pressure stage and condensed cycle fluid from a second pressure stage are simultaneously introduced into a mixing separator 500 of a first pressure stage in order to reduce overheating of the vaporous cycle fluid during compression without prior injection of liquid cycle fluid and to provide saturated vapor at a first pressure stage at the outlet 508 from the mixing separator 500.

[0118] In a minimal embodiment of the heat pump device 1 with at least three pressure levels according to Fig. 1, Fig. 2 or Fig. 3 and the preferred use of water as the cyclic process fluid, the evaporator 200 can be operated using waste heat with temperatures of, for example, 60-80 ° C at an evaporation temperature of, for example, 54 ° C, which corresponds to an evaporation pressure of the cyclic process fluid of 150 hPa. This evaporation pressure defines the operating conditions of a heat-absorbing side of the cyclic process and corresponds to the lowest condensation pressure of the cyclic process fluid within the cyclic process, which at the same time corresponds to the lowest pressure level of the heat pump device 1.

[0119] Starting from this lowest pressure level in the evaporator 200, the vaporous cycle fluid, for example, water, is compressed to a second pressure level in at least one compressor 401. The pressure of the second pressure level depends on the achievable compression ratio of the selected compressor 401, which can, for example, be in a range of 1.2-6.0. Depending on the compressor design, the vaporous cycle fluid heats up to varying degrees during compression.

[0120] Assuming an evaporation pressure of the cycle fluid in the evaporator 200 of 150 hPa and a compression ratio in the compressor 401 of, for example, 3.0, the pressure of the second pressure stage would be calculated at 450 hPa. For the cycle fluid water, the boiling and condensation temperature of the second pressure stage, corresponding to 450 hPa, would be 78.7°C.

[0121] If one compares these two pressure stages (150 hPa; 54.0°C) and (450 hPa; 78.7°C), for example, with an isentropic compression with n = K = 1.333 from an evaporator pressure stage (150 hPa; 54.0°C) to a second pressure stage with 450 hPa, which corresponds to a compression ratio of 3.0, then the temperature after the isentropic compression would be Tv2 = 157.4 °C, which, compared to the corresponding condensation temperature of the second pressure stage of TD2 = 78.7 °C, represents a superheat of Tv2 - TD2 = 157.4°C - 78.7°C = 78.7 K.

[0122] This positive temperature difference of 78.7 K makes it possible for heat to be transferred from a steam compressed to a pressure level pv2 and thus superheated to a liquid cycle fluid whose temperature corresponds at most to the corresponding boiling temperature TD2 of the pressure level pD2.

[0123] This circumstance is used to transfer the superheat enthalpy resulting from the compression to a pressure level for the evaporation of liquid cycle fluid of the same pressure level and thus to generate a higher proportion of vaporous cycle fluid at this pressure level without this additional vaporous portion having to be compressed to this pressure level by performing mechanical work, i.e. the destruction of exergy.

[0124] This is achieved by the vaporous cycle fluid compressed in a compressor 401 to a second pressure stage entering the mixing separator 400 of the second pressure stage at a connection 406 for the entry of vaporous cycle fluid and being brought into direct contact there with liquid cycle fluid of the second pressure stage, which is located in the mixing separator 400 of the second pressure stage.

[0125] Within the mixing separator 400 of the second pressure stage, the direct contact of vaporous and liquid cycle fluid and the rapid heat and mass transfer processes result in simultaneous condensation of vaporous and Evaporation of liquid cycle fluid creates a quasi-stationary equilibrium, which is supported, for example, by a cyclone effect, in order to separate vaporous cycle fluid from liquid and simultaneously allow it to exit separately from the mixing separator 400 of the second pressure stage at separate connections 408, 409, in particular vaporous cycle fluid at at least connection 408 and liquid cycle fluid at at least connection 409.

[0126] The vaporous cycle fluid which exits at least one connection 408 of the mixing separator 400 of the second pressure stage is subsequently compressed in at least one compressor 501 from the second to a first pressure stage, wherein vaporous cycle fluid of this first pressure stage passes through the heat-emitting side of the heat pump device 1 and, in the process, indirectly transfers process heat to at least one heat sink (10, 11) in a heat exchanger 520 and condenses in the process.

[0127] The transfer of process heat from the heat pump device 1 thus occurs at least through condensation of the vaporous cycle fluid at the condensation pressure of the first pressure stage and the corresponding condensation temperature. The pressure of the first pressure stage depends on the achievable compression ratio of the selected compressor 501, which can, for example, be in a range of 1.2-6.0.

[0128] Assuming a pressure of a second pressure stage of 450 hPa and a compression ratio in compressor 501 of, for example, 4.0, the pressure of the second pressure stage is then 1,800 hPa. For the cycle fluid water, the boiling and condensation temperature of the second pressure stage corresponding to 1,800 hPa is therefore 116.9°C.

[0129] During the transfer of process heat on the heat-emitting side of the heat pump device 1, vaporous cycle fluid of the first pressure stage condenses at 116.9°C in at least one heat exchanger 520 of the heat sink (10, 11), wherein condensed cycle fluid of the first pressure stage exits the heat exchanger 520 at a temperature that is not significantly below the corresponding condensation temperature of the first pressure stage and enters at least one connection 407 into a mixing separator 400 of a second pressure stage, wherein the corresponding boiling and condensation temperature of the second pressure stage, at approximately 78.7°C, is significantly below the corresponding boiling and condensation temperature of the first pressure stage of approximately 116.9°C.

[0130] Due to this temperature difference when the condensed cycle fluid of the first pressure stage enters the mixing separator 400 of the second pressure stage, whose pressure, as described, is lower than the pressure of the first pressure stage by the inverse of the compression ratio of the compressor 501, Spontaneous evaporation of a further portion of liquid cycle fluid may occur.

[0131] In such spontaneous evaporation, the excess enthalpy of the higher-temperature entering liquid cycle fluid can be used as evaporation enthalpy until it cools to the corresponding boiling and condensation temperature of the second pressure stage. With the described temperature difference of 116.9°C - 78.7°C = 38.2 K and an assumed specific heat capacity of 4.186 kJ / kg -K of the liquid cycle fluid, a specific evaporation enthalpy of approximately 2,313 kJ / kg is required for isobaric evaporation at the second pressure stage pressure of 450 hPa. Based on the mass flow of the liquid cycle fluid entering from the condensed cycle fluid of the first pressure stage to the connection 407 for entry into the mixing separator 400 of the second pressure stage, the ratio of the specific enthalpies results in a mass ratio of (4.186 kJ / kg -K • 38.2 K) / (2.313 kJ / kg) = 0.069 kg / kg of additionally vaporized cycle fluid, without this additional vaporous portion having to be compressed in a previous compression, such as in a compressor 401, by applying mechanical work to the second pressure stage.

[0132] The portion of liquid cycle fluid that enters the mixing separator 400 of the second pressure stage at a connection 407 and is not evaporated to reduce superheat or by spontaneous evaporation is referred to as excess portion of liquid Cycle fluid of the second pressure stage and exits at least at the connection 409 from the mixing separator 400, from where at least a portion is passed directly or indirectly into the evaporator 200.

[0133] In the following, the previously described minimal configuration of a heat pump device 1 according to Figures 1 to 3 with the cycle fluid water will be described with regard to the achievable heat output coefficient COPh and the thus achievable energy efficiency.

[0134] The specific condensation enthalpy corresponding to the first pressure stage (1,800 hPa; 116.9°C) is 2,213 kJ / kg, representing the process heat transferable to a heat sink (10, 11) at the corresponding condensation temperature of 116.9°C on the heat-emitting side of the heat pump device 1. For a process heat transfer of 1 MW output, a mass flow of 1,628 kg / h of circulating process fluid of the first pressure stage condensing in the heat exchanger 520 is therefore required. This flow then enters the mixing separator 400 of the second pressure stage as liquid circulating process fluid at approximately 116.9°C at a connection 407.

[0135] To deliver 1,628 kg / h of vaporous cycle fluid of the first pressure stage, compression by means of compressor 501 from a second pressure stage (450 hPa; 78.7°C) to the first pressure stage (1,800 hPa; 116.9°C) is required. In principle, a distinction can be made between dry compression and wet steam compression. In wet steam compression according to In Fig. 1 or Fig. 2, the exiting mass flow already corresponds to the required delivery mass flow of 1,628 kg / h of vaporous cycle fluid of the first pressure stage, since exactly enough liquid cycle fluid is sprayed at the inlet of compressor 501 to reduce the superheat generated during compression. With dry compression, the compression superheat would have to be reduced in the subsequent mixing separator 500 of the first pressure stage according to Fig. 3 by spraying approximately 138 kg / h of liquid cycle fluid from the mixing separator 400 of the second pressure stage into the mixing separator 500 of the first pressure stage and evaporating it due to the superheat of the dry-compressed vapor in compressor 501. These 138 kg / h of liquid cycle fluid therefore do not need to be compressed in compressor 501 by applying mechanical work to the first pressure stage.This means that the mass flow through compressor 501 only needs to be 1,628 kg / h - 138 kg / h = 1,490 kg / h. The electrical power consumption of compressor 501 is approximately 131.6 kW.

[0136] The 1,490 kg / h to be compressed in compressor 501 exits from port 408 of the mixing separator 400 of the second pressure stage. The 1,628 kg / h of liquid cycle fluid of the first pressure stage condensed in the heat exchanger 520 enters via port 407 of the mixing separator 400, of which approximately 0.069 kg / kg evaporates through spontaneous evaporation, thus approximately 112 kg / h of vaporous cycle fluid of the second pressure stage is formed through spontaneous evaporation. Of the remaining approximately For 1,516 kg / h of liquid cycle fluid in mixing separator 400, approximately 87 kg / h are required to reduce the superheat from compression to the second pressure stage, so the mass flow of vapor cycle fluid in compressor 401 must be approximately 1,490 kg / h - 112 kg / h - 87 kg / h = 1,291 kg / h. The electrical power consumption of compressor 401 is approximately 81.5 kW.

[0137] The 1,291 kg / h of vaporous cycle fluid to be compressed in compressor 401 exits the evaporator 200 and is evaporated there at the pressure stage (150 hPa; 54.0°C) of the evaporator 200 by means of indirect heating with a power of approximately 848 kW. This heating power consists of approximately 34 kW of heat recovery from the liquid cycle fluid exiting the mixing separator 400 at connection 409, as well as approximately 811 kW of waste heat from a Heat source (14, 15) .

[0138] In the alternative heat pump device 1 in a minimal configuration with only a few main components as shown in Fig. 3, a total electrical power consumption of approximately 131.6 kW + 81.5 kW + 1.9 kW = 215 kW is required for the compression of vaporous cycle fluid in the compressors (401, 501) and for various pumps (201, 222, 251) for liquid cycle fluid to deliver 1,000 kW of process heat. Thus, the heat output coefficient COPh = 4.65 with a temperature range of 116.9°C - 60°C = 56.9 K.

[0139] A compression shown in Figures 1 to 11 by means of the corresponding compressors 301, 311, 401, 501, 601 within the respective alternative of the heat pump device 1 according to the invention represents in general terms that a compression by means of the corresponding compressors 301, 311, 401, 501, 601 of a vaporous cycle takes place fluidly by performing mechanical work either in a compressor in the design of a turbomachine, such as an axial fan, a radial fan, a turbocompressor or a turbine, or that the compression of a vaporous cycle takes place fluidly by performing mechanical work in a compressor in the design of a positive displacement machine, such as a piston compressor, a rotary piston compressor or a screw compressor.

[0140] An alternative of the heat pump device 1 shown in Figure 4, in contrast to Figure 3, is that the compression is carried out by means of a compressor 401 of vaporous cycle fluid in a thermal compressor, such as a vacuum vapor jet pump, in which vaporous cycle fluid of a first pressure stage is used as motive steam, which reaches high speeds through thermal compression and thereby sucks in a suction steam in the form of vaporous cycle fluid with a pressure lower than that of the motive steam due to Venturi or Coanda effects, wherein the motive steam and suction steam then mix to form a mixed steam with the pressure of a second pressure stage, which has a higher pressure than the suction steam and a lower pressure than the motive steam.

[0141] An alternative of the heat pump device 1 shown in Figure 5, in contrast to Figure 4, has that vaporous cycle fluid from a first pressure stage is further compressed in a compressor 601 and this compressed vaporous cycle fluid is used as motive steam, which reaches high speeds in a thermal compression and thereby, due to Venturi or Coanda effects, sucks in suction steam in the form of vaporous cycle fluid with a pressure lower than that of the motive steam, wherein the motive steam and suction steam then mix to form a mixed steam with the pressure of a second pressure stage, which has a higher pressure than the suction steam and a lower pressure than the motive steam.Additionally, Figure 5 shows that cyclic process fluid condensed at the second pressure stage from the mixing separator 400 of a second pressure stage is introduced into vaporous cyclic process fluid from a first pressure stage to generate cyclic process fluid wet steam before this wet steam is compressed in the compressor 601 to a motive steam pressure stage. At the same time, a condensate pump 260 provides sufficient injection pressure of liquid cyclic process fluid from a second pressure stage before compression by the compressor 601 to a motive steam pressure stage.

[0142] An alternative of the heat pump device 1 shown in Figure 6 has, in contrast to Figure 3 that a further third pressure stage with a mixing separator 300 and a compressor 301 has been added, and liquid cycle fluid from a mixing separator (400, 500) of a second or first pressure stage is introduced into the further mixing separator (300, 400) of a second pressure stage, the pressure and temperature of which are lower than the pressure and temperature of the introduced liquid cycle fluid. A condensate pump 201 conveys the quantity of condensed cycle fluid which, in this case and in contrast to the illustration in Figures 1 to 5, exits the mixing condenser 300 of the next higher pressure stage above the pressure stage of the evaporator 200.At the same time, compression from a low to a second pressure stage can take place either in the compressor 301 in the design of a turbomachine or displacement machine, or analogously to the illustration in Figure 4 or Figure 5 in the design of a thermal compressor.

[0143] In another alternative of a The performance factor of the heat pump device 1 can be increased by increasing the number of pressure stages to, for example, at least 4 pressure stages according to Fig. 6 for the same temperature difference. If, for example, instead of a first pressure stage (1,800 hPa; 116.9°C), a second pressure stage (450 hPa; 78.7°C) and a pressure stage of the evaporator 200 (150 hPa; 54.0°C) similar to the illustrations in Figs. 1 to 3, the gradation is reduced to, for example, a first pressure stage (1,800 hPa; 116.9°C), a second pressure stage (450 hPa; 78.7°C), a third pressure stage (225 hPa; 62.6°C) and a pressure stage of the evaporator 200 (150 hPa; 54.0°C), the result is a heat output coefficient COPh = 4.71 with a temperature difference of 116.9°C - 60°C = 56.9 K, since smaller differences between the pressures of the pressure stages mean that more exergy can be recovered from the condensed cycle fluid of higher stages.

[0144] In a further alternative of a heat pump device 1, the temperature difference can be increased by increasing the compression ratios of individual compressors (301, 401, 501) while maintaining the same number of pressure stages, as shown in Fig. 6, for example. For example, if a first pressure stage (4,044 hPa; 144.0°C), a second pressure stage (674 hPa; 88.9°C), a third pressure stage (225 hPa; 62.6°C), and a pressure stage of the evaporator 200 (150 hPa; 54.0°C) are set up, a heat output coefficient COPh = 3.44 results for a temperature difference of 144.0°C - 60°C = 84.0 K.

[0145] In a further alternative of a heat pump device 1, the coefficient of performance can be increased by dividing the transfer of process heat between a first and a second heat sink with different sink temperatures according to Fig. 7, with the same temperature difference and the same number of pressure stages, for example at least four pressure stages according to Fig. 6. If all process heat is transferred at a uniform sink temperature according to Fig. 6, for example, a heat performance coefficient COPh = 3.44 can be achieved with a temperature difference of 84.0 K.

[0146] When the process heat is divided according to a further alternative of the heat pump device 1 according to Fig. 7 in such a way that approximately half is transferred to a first pressure stage and the other half to a second pressure stage by means of the heat exchangers 420, 520, a heating performance factor of at least COPh = 4.35 can be achieved, for example, without the maximum temperature difference of 84.0 K having to be reduced.

[0147] An alternative of the heat pump device 1 shown in Figure 8, in contrast to the representation in Figure 6, has that a further pressure stage with a mixing separator 310, a compressor 311 and a condensate separator 312 has been added as a third pressure stage, whereby the third pressure stage from Figure 6 became a fourth pressure stage, and liquid cycle fluid from a mixing separator 400 of a second pressure stage is introduced into the mixing separator 310 assigned to the third pressure stage, the pressure and temperature of which are lower than the pressure and temperature of the introduced liquid cycle fluid of the pressure stage above.

[0148] An alternative of the heat pump device shown in Figure 9, in contrast to the illustration in Figure 8, has the fact that compression from one pressure stage of the evaporator 200 to a fourth pressure stage in a compressor 301 can also take place in the design of a thermal compressor, as is shown analogously to the illustration in Figure 4 or Figure 5 and also applies analogously to compression processes between other pressure stages.

[0149] 1 to 9, it is clear that a heat pump device 1 according to the invention can basically be variable with regard to the number of pressure stages built up, including the required components and devices per pressure stage, and with regard to the selection of the compressor design. For example, starting from a second pressure stage, compression can also take place by means of a compressor 601 from vaporous cycle fluid to motive steam, as shown in Figure 9, in that vaporous cycle fluid is taken from a mixing separator 400 of a second pressure stage and compressed as motive steam in a compressor 601 for the operation of a steam jet vacuum pump, with which vaporous cycle fluid from any lower pressure stage or, as shown in Figure 9, from the evaporator 200 is compressed to a fourth pressure stage.

[0150] An alternative of the heat pump device 1 shown in Figure 10, in contrast to the representation in Figure 8, has that vaporous cycle fluid of a second pressure stage condenses in at least one heat exchanger 420 of a heat sink with at least one inlet 12 and at least one outlet 13 and indirectly transfers heat to these, wherein a cycle fluid condensed at a second pressure stage in the heat exchanger 420 of the heat sink is fed into a mixing separator 310 of a third pressure stage with a pressure below that of the vapor condensing in the heat exchanger 420. Cyclic process fluids enter via at least one connection 317.

[0151] An alternative of the heat pump device 1 shown in Figure 11, in contrast to the representation in Figure 10, has that vaporous cycle fluid of a third pressure stage condenses in at least one heat exchanger 420 of a heat sink with at least one inlet 12 and at least one outlet 13 and indirectly transfers heat to these, wherein a cycle fluid condensed at a third pressure stage in the heat exchanger of a heat sink enters a mixing separator 300 of a fourth pressure stage at a pressure below that of the pressure of the cycle fluid condensing in the heat exchanger 420 via at least one connection 307.

[0152] Based on the illustrations in Figures 10 and 11, it is shown that at least a second temperature level for a further process heat transfer to at least one further heat sink at the level of the condensation temperature of a second or third pressure stage is provided in at least one heat exchanger 420 of a heat sink with at least one inlet 12 and at least one outlet 13. This ensures that a process heat transfer at at least a second temperature level already enables a process heat supply up to a temperature close to the condensation temperature of that second or third pressure stage, wherein up to that point only the mechanical work for the compression up to that second or third pressure stage has to be used.

[0153] For the remaining process heat transfer down to a temperature close to the condensation temperature of a first pressure stage, only the difference in mechanical work for compression from the already reached second or third pressure stage to that first pressure stage would then be required, but with a significantly lower specific process heat demand and lower specific mechanical work for compression. Such gradual process heat provision can further advantageously reduce the specific exergy destruction relative to the total process heat transferred, further increasing the overall heat performance factor.

[0154] In an alternative, not shown, of a heat pump device 1 with a further subdivision into at least 7 pressure stages, i.e. a first pressure stage (15,550 hPa; 200, 0°C), a second (3,390 hPa; 142.6°C), a third (1,300 hPa; 107.0°C), a fourth (441 hPa; 78.2°C), a fifth (260 hPa; 65.8°C), a sixth (180 hPa; 57.7°C) and a pressure stage of the evaporator 200 (150 hPa; 54.0°C), a heating performance coefficient COPh = 2.48 can be achieved over a temperature rise of just 200, 0°C - 60°C = 140.0 K. Here, too, the coefficient of performance can be increased by dividing the process heat transfer at the same temperature lift and the same number of pressure stages. If the distribution is such that approximately half of the process heat is provided at the first pressure stage (15,550 hPa; 200.0°C) and the other half at the third pressure stage (1,300 hPa; 107.0°C), the heating performance coefficient increases by around +40% to over COPh = 3.40.

[0155] By definition, the provision of process heat requires an electrical power consumption equal to the product of the process heat and the inverse of the heat performance coefficient. This means that with a heat pump device 1, an electrical power consumption of less than 0.3 kWel / kW of process heat is required to provide process heat at a temperature level of, for example, 200°C. This corresponds to a saving of over 70% in primary energy consumption and a 100% reduction in fossil process heat generation using the heat pump device 1.

[0156] The heat pump devices 1 have a high energy efficiency and are flexible, modularly expandable and adaptable to a wide variety of requirements regarding required sink temperatures and / or other parameters. Reference symbol list 1 heat pump device 2 Control and regulation unit 5 Drying device 10 Inlet of a first heat sink 11 Process of a first heat sink 12 Inlet of a second heat sink 13 Drain of a second heat sink 14 Inlet of a heat source 15 Drainage of a heat source 200 evaporators 201 Condensate pump 202 control valve 220 heat exchangers of a heat source 222 Circulation pump 250 Condensate pump for spraying in front of a compressor 251 Condensate pump for spraying into a mixing separator 252 control valve 260 Condensate pump for spraying in front of a motive steam compressor 300 mixing separator of a third pressure stage 301 compressor to the pressure of a third pressure stage 306 Connection for the entry of vaporous Cyclic process fluid 307 Connection for the inlet of condensed Cyclic process fluid 308 Connection for the outlet of vaporous Cyclic process fluid 309 Connection for the outlet of condensed Cyclic process fluid Mixing separator of a further pressure stage Compressor to the pressure of a further pressure stage Condensate separator of a further pressure stage Connection for the inlet of the vaporous cycle fluid Connection for the inlet of the condensed cycle fluid Connection for the outlet of the vaporous cycle fluid Connection for the outlet of the condensed cycle fluid Heat exchanger of a heat sink of a third pressure stage Condensate separator of a heat exchanger of a third pressure stage Mixing separator of a second pressure stage Compressor to the pressure of a second pressure stage Condensate separator of a second pressure stage Connection for the inlet of the vaporous cycle fluid Connection for the inlet of the condensed cycle fluid Connection for the outlet of the vaporous cycle fluid Connection for the outlet of the condensed cycle fluid Heat exchanger of a heat sink of a second pressure stage Condensate separator of aHeat exchanger of a second pressure stage 500 mixing separator of a first pressure stage 501 compressor to the pressure of a first pressure stage 502 Condensate separator of a first pressure stage 506 Connection for the inlet of vaporous cycle fluid 507 Connection for the inlet of condensed cycle fluid 508 Connection for the outlet of vaporous cycle fluid 509 Connection for the outlet of condensed Cyclic process fluid 520 Heat exchanger of a heat sink of a first pressure stage 522 Condensate separator of a heat exchanger of a first pressure stage 601 Compressor for generating motive steam

Claims

Patent claims:

1. Heat pump device (1) for the energy-efficient generation of process heat, wherein the heat pump device (1) has a heat-absorbing side, a heat-emitting side, a cycle fluid, and an evaporator (200) on the heat-absorbing side, and at least one heat exchanger (520) and at least one heat sink (10, 11) can be assigned to the heat pump device (1) on the heat-emitting side, and at least one heat source (14, 15) can be assigned to the heat pump device (1), wherein, by means of the evaporator (200), liquid cycle fluid can be indirectly heated by heat supply from the assignable heat source (14, 15) and evaporated at a pressure stage of the evaporator (200), and the heat pump device (1) has at least one first compressor (401) connected downstream of the evaporator (200), wherein, by means of the at least first compressor (401), vaporous cycle fluid can be compressed from the pressure stage of the evaporator (200) to a second pressure stage,and the heat pump device (1) has at least one first mixing separator (400) in the second pressure stage, wherein the at least first mixing separator (400) has a first connection (406) for the inlet of vaporous cycle fluid, a second connection (407) for the inlet of condensed cycle fluid, a third connection (408) for the outlet of vaporous cycle fluid and optionally a fourth connection (409) for the outlet of condensed cycle fluid and at least one second compressor (501) is connected downstream of the mixing separator (400), so that vaporous cycle fluid emerging from the third connection (408) can be compressed in the at least second compressor (501) from the second pressure stage to a first pressure stage and by means of the at least one, associated heat exchanger (520), process heat can be indirectly transferred from the vaporous cycle fluid of the first pressure stage to the at least one assignable heat sink (10, 11), and the cycle fluid condensed in the at least one heat exchanger (520) can be returned via the second connection (407) to the at least first mixing separator (400) of the second pressure stage, wherein at the same time vaporous cycle fluid from the at least first compressor (401) can be introduced into the mixing separator (400) via the first connection (406), characterized in that the at least first mixing separator (400) has the fourth connection (409) for the outlet of condensed cycle fluid, so that the escaping condensed cycle fluid can be directly or indirectly returned to the evaporator (200) and / or fed to the at least second compressor (501).Heat pump device (1) according to claim 1, characterized in that the heat pump device (1) has at least one heat exchanger (520) assigned to the first pressure stage and / or one heat exchanger (420) assigned to the second pressure stage and / or one heat exchanger (320) assigned below the second pressure stage on the heat-emitting side. Heat pump device (1) according to one of the preceding claims, characterized in that the heat pump device (1) has at least one heat source (14, 15) and / or at least one heat sink (10, 11). Heat pump device (1) according to one of the preceding claims. Claims, characterized in that the Heat pump device (1) a second mixing separator, a third mixing separator, a fourth mixing separator and / or optionally further mixing separators (300, 310), wherein a further compressor (301, 311) is connected upstream of the respective mixing separator (300, 310). Heat pump device (1) according to claim 4, characterized in that one mixing separator or two or more mixing separators (300, 310) are connected upstream of the first Mixing separator (400) is or are connected upstream, wherein the vaporous cycle fluid of the respectively upstream mixing separator (300, 310) can be fed to the subsequent mixing separator (310, 400) via a respective downstream compressor (311, 401) and / or the liquid cycle fluid from the respectively downstream mixing separator (310, 400) is fed into the upstream Mixing separator (300, 310). Heat pump device (1) according to one of the preceding Claims, characterized in that the at least one heat exchanger (520) is followed by a condensate separator (522) and / or the second heat exchanger (420) is followed by a condensate separator (422) and / or the further heat exchanger (320) is followed by a condensate separator (322) for returning condensed cycle fluid from the first pressure stage to the first mixing separator (400) and / or condensed cycle fluid from the second or a third pressure stage to an upstream mixing condenser (300, 310). Heat pump device (1) according to one of the preceding Claims, characterized in that after the fourth Connection (409) for the outlet of condensed Cycle fluid of the first mixing separator, an upstream mixing separator and / or the respective mixing separator (300, 310, 400, 500), a condensate separator (312, 402, 502) for returning the condensed cycle fluid to the respective upstream mixing separator (300, 310, 400) or to the evaporator (200) is or are arranged. Heat pump device (1) according to one of the preceding claims, characterized in that a further mixing separator (500) is arranged downstream of the first mixing separator (400) in the second pressure stage, wherein the further mixing separator (500) is arranged in the first pressure stage. Heat pump device (1) according to one of the preceding claims Claims, characterized in that the heat pump device (1) has a control and / or regulating device (2) for controlling and / or regulating components of the heat pump device (1) and optionally the at least one heat source (14, 15) and / or the at least one heat sink (10, 11). Heat pump device (1) according to one of the preceding claims, characterized in that the second connection (407) for the inlet of condensed cycle fluid has a spraying device for spraying the liquid cycle fluid entering the first mixing separator or the respective mixing separator. Drying device for drying a material to be dried by means of a heated process gas stream, wherein the drying device has a heat pump device (1) according to one of claims 1 to 10, such that on the heat-emitting side of the heat pump device (1), the process gas stream can be heated as a heat sink (10, 11). Method for operating a heat pump device (1) for energy-efficient generation of process heat, in particular in a temperature range between 100°C and 250°C, by means of a heat pump device (1) according to one of claims 1 to 10, comprising the following steps: - heating a liquid cycle fluid by indirect heat supply from a heat source (14, 15) and evaporating the liquid cycle fluid in an evaporator (200) at a pressure stage of the evaporator (200), - compressing the vaporous cycle fluid by means of a first compressor (301, 401) to a second pressure stage, - Supplying the compressed vaporous Cycle fluid in at least one mixing separator (400) of a second pressure stage, - feeding the vaporous cycle fluid emerging from the at least one mixing separator (400) into at least one second compressor (501) and compressing the vaporous cycle fluid from the second pressure stage to a first pressure stage, - transferring process heat from the compressed, vaporous cycle fluid of the first pressure stage to at least one assignable heat sink (10, 11), - and optionally returning the condensed cycle fluid from the first pressure stage to the at least one mixing separator (400). The method according to claim 12, characterized in that water, an alcohol, and / or a water-soluble organic substance is or are used as the cycle fluid. Method according to one of claims 12 or 13, characterized in that a pressure increase is carried out in a stream of the condensed cycle fluid emerging from the mixing separator (300, 400) by means of a condensate pump (201), then this stream is mixed with a stream of liquid cycle fluid which has previously been indirectly heated in a heat exchanger (220) of a heat source (14, 15), and the mixed streams are used for the indirect heating of the evaporator (200).Method according to one of the preceding claims, characterized in that a pressure increase is carried out in a stream of the condensed cycle fluid emerging from the at least one mixing separator (300, 400) by means of at least one condensate pump (201), then this stream is introduced into vaporous cycle fluid from the at least one mixing separator (400) to generate cycle fluid wet steam, before the cycle fluid wet steam is compressed to the first pressure stage in the downstream compressor (501).

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