Device and method for controlling the temperature of a medium

Abstract

A device for controlling the temperature of a medium, comprising: a first circuit in which a first heating medium circulates without phase transitions; a second circuit in which a second gaseous heating medium circulates without phase transitions; a first heat converter arranged in the first circuit and in which the first medium exchanges heat with a surrounding medium: a second heat converter arranged in the first circuit and in which the first medium exchanges heat with the medium to be temperature-controlled; a first delivery means arranged in the first circuit for moving the first medium; a compressor arranged in the second circuit for compressing the second medium; a third heat converter arranged behind the compressor when seen in the flow direction so as to contact the second circuit and which exchanges heat with the first medium; and means for cooling or expanding the first medium.

Claims

1. A device for controlling the temperature of a fluid, said device comprising: a. a closed first heat transfer fluid circuit in which a first heat transfer fluid circulates, the first heat transfer fluid being selected to circulate without phase transitions in the first heat transfer fluid circuit; b. a closed second heat transfer fluid circuit in which a second, gaseous heat transfer fluid circulates, wherein the second, gaseous heat transfer fluid is selected such that it flows through the second heat transfer fluid circuit without phase transitions; c. a first heat exchanger arranged in the first heat transfer fluid circuit wherein the first heat transfer fluid is brought into heat exchange in the first heat exchanger with an ambient medium; d. a second heat exchanger arranged in the first heat transfer fluid circuit, wherein the first heat transfer fluid is brought into heat exchange in the second heat exchanger with a fluid whose temperature is to be controlled; e. a first conveying means arranged in the first heat transfer fluid circuit for moving the first heat transfer fluid in the first heat transfer fluid circuit; f. a compressor arranged in the second heat transfer fluid circuit for compressing the second, gaseous heat transfer fluid; g. a third heat exchanger that is disposed downstream of the compressor and in contact with the second heat transfer fluid circuit as seen in the flow direction of the second heat transfer fluid and wherein the third heat exchanger exchanges heat with the first heat transfer fluid in the first heat transfer fluid circuit; h. a means for cooling down or expanding the first heat transfer fluid in the first heat transfer fluid circuit; and i. wherein the device further comprises a fourth heat exchanger provided in the device, wherein the fourth heat exchanger is integrated in the second heat transfer fluid circuit and is arranged upstream of the compressor, and wherein the fourth heat exchanger is in a heat exchange connection with the first heat transfer fluid routed in the first heat transfer fluid circuit.

2. The device according to claim 1, wherein a liquid is used as the first heat transfer fluid, and wherein the liquid is liquid at atmospheric pressure in a temperature range of from about 50 C. up to about +60 C.

3. The device according to claim 1, wherein the first heat transfer fluid is a hydrofluoroether.

4. The device according to claim 1, wherein the means for cooling down the first heat transfer fluid comprises at least one Peltier element.

5. The device according to claim 1, wherein the fourth heat exchanger comprises three separate pipeline strands that are mutually heat exchanging, wherein a first pipeline strand of the three separate pipeline strands belongs to the second heat transfer fluid circuit, a second pipeline strand of the three separate pipeline strands belongs to a first section of the first heat transfer fluid circuit; and a third pipeline strand of the three separate pipeline strands belongs to a second section of the first heat transfer fluid circuit.

6. The device according to claim 5, wherein the second section of the first heat transfer fluid circuit to which the third pipeline strand belongs, is incorporated into the first heat transfer fluid circuit or is-separated therefrom and is bypassed using valves.

7. The device according to claim 5, further comprising an expansion valve arranged in the second section.

8. The device according to claim 1, wherein the first conveying means is reversible with respect to a conveying direction.

9. The device according to claim 1, wherein the compressor is a turbocompressor.

10. A method for controlling the temperature of a fluid comprising: routing a first heat transfer fluid in a closed first heat transfer fluid circuit; circulating the first heat transfer fluid in the first heat transfer fluid circuit by a first conveying means to absorb or give off heat; routing the first heat transfer fluid in the first heat transfer fluid circuit through a first heat exchanger to exchange heat with an ambient medium; routing the first heat transfer fluid through a second heat exchanger to exchange heat with a fluid whose temperature is to be controlled; wherein the first heat transfer fluid is routed in the first heat transfer fluid circuit without undergoing phase transitions in the first heat transfer fluid circuit; wherein for heating the fluid whose temperature is to be controlled, the first heat transfer fluid is routed by the conveying means through the first heat exchanger in order to absorb heat there; wherein the first heat transfer fluid is routed through a third heat exchanger after having flowed through the first heat exchanger, wherein the third heat exchanger is integrated in a closed second heat transfer fluid circuit in which a second, gaseous heat transfer fluid is circulated without phase transitions; wherein a compressor is disposed upstream of the third heat exchanger in the second heat transfer fluid circuit as seen in the direction of flow of the second heat transfer fluid, and wherein the compressor compresses and heats the second heat transfer fluid; wherein the first heat transfer fluid absorbs heat from the second heat transfer fluid in the third heat exchanger, in that the first heat transfer fluid is routed through the second heat exchanger after passing through the third heat exchanger; wherein in the second heat exchanger, the first heat transfer fluid gives off heat to the fluid whose temperature is to be controlled and the first heat transfer fluid is expanded or is cooled down and is returned to the first heat exchanger after flowing through the second heat exchanger; and wherein the method further comprises: routing the first heat transfer fluid through a fourth heat exchanger after the first heat transfer fluid has flowed through the second heat exchanger and prior to the first heat transfer fluid flowing through the first heat exchanger again; integrating the fourth heat exchanger into the second heat transfer fluid circuit and through which the second heat transfer fluid flows before the second heat transfer fluid is compressed by the compressor; routing the first heat transfer fluid through the fourth heat exchanger in a further section of the first heat transfer fluid circuit and after passing through the first heat exchanger and prior to passing through the third heat exchanger; wherein the first heat transfer fluid absorbs heat in this further section of the first heat transfer fluid circuit in this fourth heat exchanger from both the second heat transfer fluid and from the first heat transfer fluid recirculated in a section between the second heat exchanger and the first heat exchanger in the direction of the first heat exchanger.

11. The method according to claim 10, further comprising expanding or cooling the first heat transfer fluid between the first heat exchanger fluid exits the fourth heat exchanger or before the first heat exchanger fluid re-enters the first heat exchanger.

12. The method according to claim 10, further comprising: reversing a conveying direction of the conveying means for cooling the fluid whose temperature is to be controlled and thus reversing the flow direction of the first heat transfer fluid; simultaneously interrupting or disconnecting the second heat transfer fluid circuit; wherein the first heat transfer fluid is routed through the second heat exchanger to absorb heat from the fluid whose temperature is to be controlled, then flows through the third heat exchanger without performing a further heat exchange, or the first heat transfer fluid is routed around the third heat exchanger, then flows through the first heat exchanger to transfer heat to the ambient medium, and then is returned to the second heat exchanger for again absorbing heat from the fluid whose temperature is to be controlled; and wherein the first heat transfer fluid passes through this first heat transfer circuit without phase transitions.

13. The method according to claim 12, further comprising actively cooling the first heat transfer fluid in a section of the first heat transfer fluid circuit (downstream of the first heat exchanger and upstream of the second heat exchanger.

14. The method according to claim 10, further comprising: using a liquid as the first heat transfer fluid, which liquid is liquid at atmospheric pressure and in a temperature range of from about 50 C. up to about +60 C.

15. The method according to claim 10, further comprising: using a hydrofluorether as the first heat transfer fluid.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further advantages and features of the invention will become apparent from the following description of an exemplary embodiment based on the attached figures. In the figures:

(2) FIG. 1 shows a schematic representation of a device for controlling the temperature of a fluid in a first possible embodiment of the invention, including an illustration of the procedure;

(3) FIG. 2 shows a schematic representation of a device for controlling the temperature of a fluid in a second possible embodiment of the invention, including an illustration of the procedure, and;

(4) FIG. 3 shows a schematic representation of a section of the device according to the illustration in FIG. 2, including the illustration of an active cooling of the Peltier elements.

LIST OF THE REFERENCE NUMERALS

(5) 1, 1 heat exchanger 2 pipeline 3 first circuit 4 pipe section 5, 5 heat exchanger 6 pipeline 7 heat exchanger 8 pipe section 9 heat exchanger 10 pipe section 11 pipe section 12 recirculation pump 13 pipe section 14 three-way valve 15 three-way valve 16 inlet 17 outlet 18 expansion valve 19 Peltier element 20 second circuit 21 pipe section 22 turbocompressor 23 pipe section 24 return pipeline 25 ventilator 26 fan 27 pipeline 28 pipeline section 29 fan 30 supply pipeline three-way valve 31 recirculation pump 32 three-way valve 33 three-way valve 34 bypass pipeline 35 three-way valve 36 three-way valve 37 return pipeline three-way valve

Way(s) for Implementing the Invention

(6) In the figures, possible implementations of a device according to the invention for controlling the temperature of a fluid are outlined in principle in two embodiments slightly modified in relation to each other. In addition, a further modification is outlined in FIG. 3, which modification can be selected for both basic embodiments shown in the preceding figures. The figures also contain representations, which illustrate the procedure of a method according to the invention to be performed using these devices.

(7) FIG. 1 shows, first of all, a first heat exchanger 1, which in this embodiment variant is a heat exchanger for providing a heat transfer between a gaseous ambient medium and a circulating heat transfer fluid routed in a pipeline 2. The first heat transfer fluid is routed in a first circuit 3. The pipeline 2 in the heat exchanger 1 is connected to a pipe section 4, which is part of a supply pipeline to a second heat exchanger 5, through which, in turn, the first heat transfer fluid flows in a pipeline 6 and which serves for exchanging heat between this first heat transfer fluid and a gaseous fluid.

(8) In the supply pipeline, starting from the first heat exchanger 1 behind the pipe section 4, a further heat exchanger 7 is arranged, through which the heat transfer fluid supplied in the pipe section 4 flows and which leaves the heat transfer fluid via a further pipe section 8.

(9) The flow can also pass through the heat exchanger 7 in the reverse direction, as will be explained later. The pipe section 8 is then connected to another heat exchanger 9, through which the heat transfer fluid flows to a subsequent pipe section 10, which then opens into the second heat exchanger 5, which pipe section 10 is connected to the pipeline 6 in this heat exchanger 5. Another pipe section 11 is connected to the heat exchanger 5, more precisely to the pipeline 6, on an opposite side and leads to a recirculating pump 12. Two switchable 3-way valves 14, 15 are arranged in a pipe section 13 downstream of the recirculation pump 12. In separate switching positions these permit either a routing of the flow of the first heat transfer fluid via a supply pipeline 16 through the heat exchanger 7 and back via an outlet 17, in which a controllable expansion valve 18 is provided, to the pipe section 13 or bypassing this loop through the heat exchanger 7 directly further in the pipe section 13. Viewed from the recirculation pump 12 at least one controllable Peltier element 19 is arranged beyond the 3-way valves 14, 15, several such elements may also be provided. The pipe section 13 then opens again into the pipeline 2 of the heat exchanger 1 and in that way closes the circuit 3.

(10) In the device illustrated in FIG. 1, another circuit 20 is implemented, in which a second heat transfer fluid circulates. Here, the second heat transfer fluid flows through the heat exchanger 7, then passes into a pipe section 21 and is compressed by a turbocompressor (in particular a micro-turbocompressor) 22, routed through a piece of pipe 23 to the heat exchanger 9 and then via a return pipeline 24 back to the heat exchanger 7.

(11) The device shown in FIG. 1 can now be operated in two modes, namely in one way as a heat pump to heat an active fluid routed through the heat exchanger 5, and in another way as an air conditioning device (air conditioning) to cool down an active fluid routed through the heat exchanger 5.

(12) Below, first the use as a heat pump is described, in which the recirculating pump 12 makes the first heat transfer fluid in the circuit 3 circulate in a clockwise direction in the illustration of FIG. 1.

(13) The direction of operation of the heat transfer fluids in the heat transfer fluid circuits 3 and 20 is illustrated for the first circuit 3 by the filled arrows and by the broken pipeline arrows for the second circuit 20.

(14) In this mode of operation, ambient heat (e.g., from outside or exhaust air) is transmitted to the first heat transfer fluid in the first heat exchanger 1 as it passes pipeline 2. The first heat exchanger 1 may in particular be a fin heat exchanger with fan 25.

(15) The first heat transfer fluid is transported by the recirculating pump 12 in clockwise direction in the closed heat transfer fluid circuit 3 and delivers the absorbed ambient heat to the heat exchanger 7.

(16) In the heat exchanger 7, the temperature level of the first heat transfer fluid is raised by the waste heat, which originates from the return from the heat exchanger 5, and by cooling the second heat transfer fluid in the second circuit 20. In practice, the temperature level can be raised to approx. 30 C. if the temperature of the second heat transfer fluid in the return is cooled down to approx. 30. The 3-way valves 14, 15 are accordingly in each case in a switching position, in which the inlet 16 and the outlet 17 are integrated into the circuit 3.

(17) The speed-controlled turbocompressor 22, which may in particular be a micro-turbocompressor, takes in, compresses and raises the second heat transfer fluid (e.g., cooled to about 30 C.) to a high temperature level in the closed second circuit 20 in a diabatic process, the so-called heat of compression is impressed.

(18) The second heat transfer fluid heated in this manner encounters the first heat transfer fluid again in the heat exchanger 9, which first heat transfer fluid is routed around the turbocompressor in the pipe section 8, and heats the first heat transfer fluid to a usable temperature.

(19) The heated first heat transfer fluid flows to the heat exchanger 5, which in this exemplary embodiment can be a fin heat exchanger having a fan 26. In this heat exchanger 5, the first heat transfer fluid transfers this heat to an active fluid, e.g. aspirated fresh air.

(20) The first heat transfer fluid comes from the heat exchanger 5 and flows through the 3-way valve 14 to the heat exchanger 7 for using the waste heat; the temperature of the return can, upon exiting the heat exchanger 7, be e.g. approx. 10 C.

(21) The first heat transfer fluid cooled down to approx. 10 C. reaches the controllable Peltier elements 19 through the 3-way valve 15. On the way there, the controllable expansion valve 18 can expand and cool down the first heat transfer fluid. At the Peltier elements 19, the Peltier effect lowers the temperature of the heat transfer fluid to about 10K below the ambient heat. The heat produced on the other side of the Peltier element during the cooling can also advantageously be used to preheat the ambient heat. In this way, the energy consumed in the Peltier elements 19 is utilized in the best possible way. The Peltier elements 19 are controllable and the desired temperature range can be set.

(22) After having been cooled by the controllable Peltier elements 19, the first heat transfer fluid returns to the heat exchanger 1. The cycle can start anew. It is important to mention that throughout the cycle, the first heat transfer fluid does not undergo any phase transitions. Rather, the first heat transfer fluid is a liquid, which remains liquid under all conditions occurring in the course of the first circuit 3. The first heat transfer fluid is in particular a hydrofluoroether, e.g. ethoxynonafluorobutane (C.sub.4F.sub.9OC.sub.2H.sub.5).

(23) The second heat transfer fluid also does not undergo a phase change, but remains gaseous throughout the entire passage of the second circuit 20.

(24) As already mentioned, the device constructed according to the diagram shown in FIG. 1 can be operated not only as a heat pump, but also for cooling or air-conditioning an active fluid.

(25) The device is operated as follows; this operation is represented by the unfilled arrows drawn with an unbroken contour line in the figure.

(26) When operating the device as an air conditioner, the second circuit 20 is disabled; the turbocompressor 22 is not needed for cooling purposes and therefore remains out of service.

(27) In such a mode of operation of the apparatus as an air conditioner, the ambient medium (e.g., outside or exhaust air) is preferably colder than the first heat transfer fluid in order to transfer heat from the first heat transfer fluid in the heat exchanger 1 to the ambient medium. However, the device also works when the ambient medium is warmer than the first heat transfer fluid when it flows through the heat exchanger 1 in the pipeline 2.

(28) After the heat transfer fluid has absorbed ambient heat or released heat to the ambient medium, it flows through the controllable Peltier elements 19 for a possibly required further cooling. This is effected by the recirculation pump 12, which makes the first heat transfer fluid now flow through the first circuit 3 in the opposite direction. For this purpose, the direction of flow of the recirculation pump 12 is designed to be reversible. In the illustration of the figure, the recirculating pump 12 moves the first heat transfer fluid in the counterclockwise direction in the circuit 3.

(29) A controller preferably controls the energy consumption of the Peltier elements 19 such that a difference between the temperature of the ambient medium and the temperature of the first heat transfer fluid is e.g. approx. 10 K.

(30) After the temperature reduction, the first heat transfer fluid flows through the two 3-way valves 14, 15, which are set such that the heat transfer fluid is directly passed into the pipe section 11 without reaching the heat exchanger 7. I.e. the first heat transfer fluid reaches the heat exchanger 5 directly.

(31) In this heat exchanger 5, the heat transfer fluid absorbs heat from the working fluid and cools it down. In the device according to FIG. 1, this working fluid can be in particular fresh air that has been aspirated and cooled, which is then returned to spaces to be air-conditioned, e.g. the passenger compartment of a vehicle.

(32) The first heat transfer fluid emerges at a higher temperature from the heat exchanger 5 than it had when it has entered this heat exchanger 5, and flows to the heat exchanger 9. The first heat transfer fluid flows through this heat exchanger 9 and on to the heat exchanger 7 without any further heat exchange. For this purpose, the first heat transfer fluid is bypassed around the turbocompressor 22 in the pipe section 8.

(33) Now the first heat transfer fluid again flows through the heat exchanger 1 and there, if it is at a higher temperature level than the ambient temperature, gives off heat, then the cycle starts anew.

(34) It is also possible to provide a further pipeline route, which can be toggled in particular using valves, in which the first heat transfer fluid passes directly from the heat exchanger 5 to the heat exchanger 1, thereby bypassing the heat exchangers 7 and 9, which in this mode make no functional contributions to the cooling process anyway.

(35) FIG. 2 shows a sketch of a device constructed along the same general principle, which operates according to the same principle, such that reference can be made in this respect to the above description. The only difference between the illustration in FIG. 2 and that in FIG. 1 is that the heat exchangers 1 and 5 shown in FIG. 1 have been replaced by heat exchangers 1 and 5 in the design according to FIG. 2, wherein the heat exchangers 1 and 5 are now also connected to a pipeline system at the entry and exit sides and are not freely traversed by air as is the case with fins. Of course, in any case, a gaseous fluid, e.g. air, may also pass through one of the pipeline systems in this heat exchanger, in particular the pipeline 27 and/or the pipeline section 28. In such an embodiment, the device is suitable for instance for heating living spaces, for instance, by supplying a fluid for transporting geothermal heat to the heat exchanger 1 in a pipeline 27 and by using the heat exchanger 5 for heating a heat transfer fluid, for instance water, in a pipeline section 28 of a heating circuit. In reverse operation as described above, living spaces can be cooled (air-conditioned) as well.

(36) Finally, FIG. 3 shows a variant by depicting a detail or a partial section of the illustration according to FIG. 2 in whichif the device is used for air conditioning (cooling) - the Peltier elements 19 are actively cooled on their heat-emitting side. Such an active cooling may be required in particular if the ambient temperature is particularly high. If the device is used, for instance, in the context of a vehicle, the airstream may suffice to dissipate the heat released by the Peltier elements in each case at their heat-dissipating part. This may be more difficult for stationary systems.

(37) For this purpose, a fan 29 may initially be provided. If the provision of such a fan 29 is sufficient to adequately cool the Peltier element(s) on their heat-emitting sides, no further cooling measures are required. If the supply of fresh air by means of the fan 29 alone does not suffice, then additionally or alternatively a further cooling mechanism may be provided, e.g. such as outlined in FIG. 3.

(38) Cooling by means of a heat transfer fluid is provided there, the first heat transfer fluid from the heat transfer fluid circuit 3 being used in this embodiment.

(39) Heat transfer fluid flowing in a supply pipeline 30 absorbs waste heat from the Peltier element(s) 19. A recirculation pump 31 then conveys the heat transfer fluid in the direction of a 3-way valve 32. The 3-way valve 32 can be connected to the inlet 16. If, in the cooling mode of the device, the 3-way valve 32 is connected to the inlet 16, this inlet 16 is separated from the pipeline formed by the pipe sections 11 and 13 by means of the 3-way valve 14. As a result, the first heat transfer fluid, after flowing through the 3-way valve 32, is routed via the inlet 16 to a further 3-way valve 33. In this operating mode, the latter blocks the inlet 16 from the heat exchanger 7 and transfers the flow from the first heat transfer fluid to a bypass pipeline 34 instead. This is connected to a further 3-way valve 35, which is connected to the outlet 17. In this mode of operation, the 3-way valve 35 shuts the outlet 17 of the heat exchanger 7 and routes the first heat transfer fluid to the expansion valve 18. There, the first heat transfer fluid is expanded and thereby cooled down. A further 3-way valve 36 downstream of the expansion valve 18, which in this mode of operation closes the outlet 17 of the 3-way valve 15, is used to transfer the cooled and expanded heat transfer fluid to a return pipeline 37 connected to the 3-way valve 36 and from there again to the Peltier elements 19, where it again absorbs waste heat, and to then return to the supply pipeline 30. This cycle is activated by a controller switching the relevant 3-way valves 32, 33, 35 and 36 if the device is operating in the cooling mode and therefore an active cooling of the Peltier elements 19 is required.

(40) Of course, as the person skilled in the art recognizes offhand, a corresponding pipeline and valve arrangement and circuit can also be implemented for the exemplary embodiment of a device according to the invention shown in FIG. 1.

(41) It is also possible to operate an active cooling of the Peltier element (s) 19 as described above, in heat pump mode as well, for instance if the first heat transfer fluid has to be cooled down particularly far in order to be able to absorb ambient heat at a low temperature level in the heat exchanger 1 or 1, respectively. In such a case, then the short-circuit pipeline 34 is typically not used, the 3-way valves 33 and 35 may be connected such that the heat exchanger 7 remains integrated in the circuit. In addition, in such a circuit, the 3-way valves 14 and 15 are connected such that they integrate the inlet 16 and the outlet 17. The 3-way valves 32 and 36 are then switched such that they open both a connection to the 3-way valves 14 and 15 and the connection in the direction of the recirculation pump 31 and the return pipeline 37. The 3-way valve 32 also has to have a check valve, to prevent the first heat transfer fluid, pressurized by means of the recirculation pump 12, from flowing into the 3-way valve 32 in the direction opposite to the intended direction from the inlet 16 from the 3-way valve 14.

(42) In this case the flow directions and flow patterns of the first cooling fluid for the first cooling fluid circuit 3 if operated as a heater (heat pump) or as a chiller (for air conditioning) are indicated in FIG. 3 using arrows, as can be seen in the legend arranged in the figure.

(43) A special feature of the invention is the selection of the first heat transfer fluid. As already mentioned, this is preferably a hydrofluoroether (a chemical compound having the molecular formula C.sub.xF.sub.yOC.sub.mH.sub.n, where x is a number from 1 to 12; y is a number from 0 to 25; m is a number from 1 to 12 and n is a number from 0 to 25). Such compounds are liquid at normal temperature and pressure. Their setting point is typically in the temperature range from 38 C. to 138 C., and the boiling point is between 34 C. and 128 C. These compounds are liquid between setting point and boiling point. The densities of these liquids are significantly higher than those of heat transfer fluids used in known and pertinent devices. This fluid is also electrically nonconductive, i.e. it can be used as a cooling fluid for cooling the Peltier elements 19, to which a voltage has been applied, in the manner described above, without leading to a short circuit or the like.

(44) The global warming potential (GWP) of such compounds is also very significantly lower than the GWP of previously used heat transfer fluids, namely between 5 days and 4.9 years. Hydrofluoroethers are compatible with many metals, plastics and elastomers, permitting the use of smaller components of lower cost in the implementation of devices operated using these fluids.

(45) Unlike the heat transfer fluids used hitherto, hydrofluoroethers are not dangerous goods and do not need to be specially treated in accordance with the legislation during transport, assembly, repair or service, disassembly or accidents. Rather, they are accordingly simpler and less risky to handle and use, and more environmentally friendly.

(46) Hydrofluoroethers are also not electrically conductive, non-flammable and not combustible and can therefore also be used where there is a fire hazard in case of an accident, where short circuits in the electrical circuit would be possible or environmental hazards might develop.

(47) A harmless gaseous heat transfer fluid, for instance air, may be used in the second heat transfer fluid circuit.

(48) The turbocompressor in the second heat transfer fluid circuit can operate at a pressure of only up to 4 bar and yet already achieve sufficient heating of the second heat transfer fluid. The comparatively low pressure significantly reduces the risk of accidents, leaks, and environmental hazards.

(49) Only a small volume of the second heat transfer fluid is required in the second heat transfer fluid circuit. Furthermore, the pressure there is low and a second heat transfer fluid is also preheated before entering the turbocompressor, i.e. the required electrical power in heat pump mode of the device is very low. A further reduction of the required electrical power can be achieved if the turbocompressor is equipped with a gas or a magnetic bearing.

(50) Advantages of the turbocompressors, in particular the preferred micro-turbocompressors used, are, amongst others only very small mechanical losses and thus a very high efficiency rate. It is easy to control the power output of turbocompressors. They can be used to cover a wide output spectrum. In contrast to the usual scroll compressors in known devices, the turbocompressors are characterized in that there is no pressure pulsation. There is also no need for a lubricant, such as oil in the scroll compressors, with turbocompressors. They havein particular as micro-turbocompressorsvery small design sizes. A 5,000 W micro-turbocompressor, for instance, has the dimensions: length 25.4 cm, diameter 8.0 cm. For comparison purposes: A scroll compressor of the same output has the dimensions: length 60.0 cm and diameter 40.0 cm. As a result, the turbocompressors are also very light compared to the usual scroll compressors. Turbocompressors are virtually maintenance-free and therefore have extremely low operating costs. The lifetime of these compressors is many times higher than that of scroll compressors.

(51) Micro-turbocompressors can have the disadvantage that the very high speeds of the impeller shaft (up to 500,000 rpm at peak load, normally between 80,000 rpm and 180,000 rpm) can cause noise, these are, however, manageable.

(52) Due to the new process and use of modified parts and components, a significant increase in COP and JAZ is achieved.