EP3320279B1 - Device and method for controlling the temperature of a medium - Google Patents

Description

The present invention relates to a device and a method for temperature control of a medium according to the preambles of claims 1 and 11, respectively.

The air conditioning of vehicles such as cars, trucks, buses, trams, passenger coaches and the like, as well as of buildings such as residential buildings, office buildings, workshops, production halls and the like, is important for the well-being and safety of the people who are in vehicles and rooms .

Full air conditioning in accordance with DIN EN 13779 is used when the air conditioning system ensures ventilation, heating, cooling, humidification and dehumidification. Partial air conditioning is available in the following variants: ventilation and heating with and without a humidification function, with a cooling function and with a cooling and humidification function.

Known means for the air conditioning of rooms or the temperature control of media, which can then bring about the air conditioning of rooms, are heat pumps (for heating) and air conditioning systems (for cooling). So are air conditioners (for cooling) in the WO 00/65287 A1 discloses in which air is used in one coolant circuit and a liquid is used in another, the coolant circuits being in communication with one another via a heat exchanger. By means of a further heat exchanger, heat from a medium to be cooled is then absorbed by the heat medium circulating in the second cooling circuit. In the EP 690 275 A2 is an air conditioner (for the Cooling) with a primary and a secondary cooling circuit, each of which has a heat medium flowing through it and which are connected to one another via a heat exchanger. By means of a further heat exchanger, heat from a medium to be cooled is then absorbed from the heat medium circulating in the second cooling circuit, it being provided that the medium in the primary circuit is under a pressure of at least 0.2 MPa (2 bar).

Such elements can also be used as temperature control units for machines and systems for heating or cooling a working medium, e.g. a liquid, for operating cooling or temperature control devices, e.g. in connection with household appliances, so-called "white devices".

• Es gibt einen Wärmemediumkreislauf, wobei ein in dem Wärmemediumkreislauf geführtes Wärmemedium verdampft und verflüssigt wird
• Es gibt einen Verdampfer (meist Plattenwärmeübertrager), in dem das Wärmemedium einem Phasenübergang unterzogen (verdampft) wird.
• Es gibt einen Verdichter bzw. Kompressor für das Verdichten des Wärmemediums (hauptsächlich sind dies Scroll-Verdichter).
• Es gibt einen Kondensator bzw. Verflüssiger (meist Plattenwärmeübertrager) zum Verflüssigen des zuvor in dem Verdampfer dem Phasenübergang unterzogenen Wärmemediums.
• Es gibt ein Expansionsventil zum Entspannen des Wärmemediums.
• Es wird in der Regel ein klimaschädliches Wärmemedium verwendet (meistens R134a, R407c, R410a). Diese Wärmemedien haben ein sehr hohes Erderwärmungspotential (GWP) [nach Bundesfachschule Kälte-Klima: für R134a: 1.430, entspricht 19,86 Jahre, für R407c: 1.770, entspricht 24,58 Jahre, für R410a: 2.090. entspricht 29,03 Jahre].

Typical features of such state-of-the-art heat pumps and air conditioning systems are as follows:

• There is a heat medium circuit, wherein a heat medium carried in the heat medium circuit is evaporated and liquefied
• There is an evaporator (usually plate heat exchanger) in which the heat medium is subjected to a phase transition (evaporated).
• There is a compressor for compressing the heating medium (mainly scroll compressors).
• There is a condenser or liquefier (usually plate heat exchanger) for liquefying the heat medium that has previously undergone the phase transition in the evaporator.
• There is an expansion valve to relax the heat medium.
• As a rule, a climate-damaging heating medium is used (mostly R134a, R407c, R410a). These heating media have a very high global warming potential (GWP) [according to the Federal Technical School Kälte-Klima: for R134a: 1,430, corresponds to 19.86 years, for R407c: 1,770, corresponds to 24.58 years, for R410a: 2,090. corresponds to 29.03 years].

A heat pump commonly used today is under considerable pressure of up to over 20 bar. This increases the risk of leaks and accidents. Also have to Appropriate safe materials and thicker materials are used.

Because of the use of the above-mentioned and other heat media that are customary today, not every material that is basically suitable for the temperatures can be used for the construction of corresponding devices.

The evaporator used in today's systems is typically a special production of a heat exchanger, since a change in the physical state from liquid to gaseous takes place within the heat exchanger.

Scroll compressors run smoothly, have high efficiency due to low mechanical losses and have minimal compression dead space. However, one of the disadvantages of scroll compressors is the low compression end temperature, which must be minimized by injecting 10% -15% of the heating medium if the temperature is too high. Another major disadvantage is the very limited power control (with the exception of some Japanese models). Scroll compressors have low pressure fluctuations (pressure pulsation).

This type of compressor (scroll compressor) requires lubrication with oil. Polyvinyl ether oil (PVE) or polyolester oil (POE) is used for this. The POE reacts chemically with water and forms an acid, which places corresponding requirements on the selection of the material, which must be acid-resistant. This reduces the service life of the compressor and increases the need for repairs.

Another disadvantage of scroll compressors is the high oil throw, since a high oil throw also means a high amount of oil in the compressor circuit. To ensure environmental protection, an oil pan is required, which, when installed outdoors or in the case of possibly cold installation locations, requires an electrical belt heater and thus also requires additional energy input for the operation of the system.

The condenser or liquefier is typically also a special production of a heat exchanger, since a change in the physical state takes place in it too, here from gaseous to liquid.

When used as a heat pump for heating, the environmental heat is transported from the evaporator to the compressor at a low temperature level in the gaseous state. From the compressor to the condenser, the heat is also transported in gaseous form at a high energy level. From the condenser to the expansion valve, the heat is transported at a medium temperature level in the liquid state. From the expansion valve to the evaporator, the heat transfer medium is liquid and has a very low energy level.

When used as an air conditioning system to cool vehicles, the heat medium is compressed in a compressor that is directly connected to the vehicle engine via a compressor coupling. After compression, the heat medium is under high pressure and is gaseous. The gaseous heat medium then flows to the condenser and is cooled there by the airflow and the condenser fan. Now the heating medium is under high pressure, but it is liquid. The heating medium then flows into a filter drier and remains liquid under high pressure until the next expansion valve. In the expansion valve, the heating medium is relaxed and cools down. The pressure becomes low and the heating medium is still liquid. The cool, liquid heat medium now flows through the evaporator. By means of a fan, air is sucked in through the evaporator and blown into the passenger compartment as cool air. The warm fresh air drawn in heats up the heat medium in the evaporator and becomes gaseous again under low pressure. The gaseous heat medium now flows under low pressure through the expansion valve to the compressor. There it is compressed again and the cycle begins again.

An important decision criterion for heat pumps and air conditioning systems is the so-called COP value (Coefficient of Performance; for heat pumps) or the so-called EER value (Energy Efficiency Ratio; for air conditioning systems). This value is calculated from the amount of heat generated divided by the electrical energy used (for Compressor, control, regulation and internal pumps of the heat pump or the air conditioning system) in full load operation. A typical size of the COP or EER is between 3 and 6;

Another important assessment criterion for heat pumps is the so-called JAZ (annual performance factor). This is calculated from the amount of heat actually emitted divided by the electrical energy actually supplied (also outside the heat pump, which is required for heating). Typical sizes for the JAZ are between 2.5 and 4.

Another criterion, the so-called ESEER value (European Seasonal Energy Efficiency Ratio) takes into account the partial load operation of the air conditioning system or heat pump, because an inverter air conditioning unit or heat pump works almost exclusively in partial load operation.

Starting here and specifying a device and a method for controlling the temperature of a medium which eliminates the above-mentioned disadvantages and in particular shows high energy efficiency is the object of the invention. The aim is also to specify, at least in one advantageous development, a device for controlling the temperature of a medium which is constructed and set up for operation both as a heating device and for air conditioning. As far as possible, the invention is intended to avoid the large size and heavy weight of known devices.

This object is achieved by a device with the features of claim 1. Advantageous developments of such a device are specified in claims 2 to 9. A method according to the invention is set out in claim 10. Advantageous further developments can be found in claims 11 to 15.

1. a. einen ersten geschlossenen Wärmemediumkreislauf, in dem ein erstes Wärmemedium zirkuliert, wobei das erste Wärmemedium so gewählt ist, dass es ohne Phasenübergänge in dem ersten Wärmemediumkreislauf zirkuliert;
2. b. einen zweiten geschlossenen Wärmemediumkreislauf, in dem ein zweites, gasförmiges Wärmemedium zirkuliert, wobei das zweite, gasförmige Wärmemedium so gewählt ist, dass es ohne Phasenübergänge den zweiten Wärmemediumkreislauf durchströmt;
3. c. einen ersten, in dem ersten Wärmemediumkreislauf angeordneten, Wärmeübertrager, in dem das erste Wärmemedium mit einem Umgebungsmedium in Wärmeaustausch gebracht werden kann;
4. d. einen zweiten, in dem ersten Wärmemediumkreislauf angeordneten, Wärmeübertrager, in dem das erste Wärmemedium mit dem zu temperierenden Medium in Wärmeaustausch gebracht werden kann;
5. e. ein in dem ersten Wärmemediumkreislauf angeordnetes erstes Fördermittel zum Bewegen des ersten Wärmemediums in dem ersten Wärmemediumkreislauf;
6. f. einen in dem zweiten geschlossenen Wärmekreislauf angeordneten Verdichter zum Komprimieren des zweiten, gasförmigen Wärmemediums;
7. g. einen dritten Wärmeübertrager, der in Strömungsrichtung des zweiten Wärmemediums gesehen hinter dem Verdichter und in Kontakt mit dem zweiten Wärmemediumkreislauf angeordnet ist und in Wärmeaustausch mit dem ersten Wärmemedium in dem ersten Wärmemediumkreislauf steht;
8. h. ein Mittel zum Abkühlen und/oder Entspannen des ersten Wärmemediums in dem ersten Wärmemediumkreislauf;
9. i. einen in den zweiten Wärmemediumkreislauf integrierten vierten Wärmeübertrager, der dort in Durchströmungsrichtung gesehen vor dem Verdichter angeordnet ist und der mit dem in dem ersten Wärmemediumkreislauf geführten ersten Wärmemedium in Wärmeaustauschverbindung steht.

The device according to the invention for controlling the temperature of a medium accordingly has the following components:

1. a. a first closed heat medium circuit in which a first heat medium circulates, the first heat medium being selected so that it circulates in the first heat medium circuit without phase transitions;
2. b. a second closed heat medium circuit in which a second, gaseous heat medium circulates, the second, gaseous heat medium being selected such that it flows through the second heat medium circuit without phase transitions;
3. c. a first, arranged in the first heat medium circuit, heat exchanger, in which the first heat medium can be brought into heat exchange with an ambient medium;
4. d. a second, arranged in the first heat medium circuit, heat exchanger, in which the first heat medium can be brought into heat exchange with the medium to be tempered;
5. e. a first conveying means arranged in the first heat medium circuit for moving the first heat medium in the first heat medium circuit;
6. f. a compressor arranged in the second closed heat circuit for compressing the second, gaseous heat medium;
7. G. a third heat exchanger, which is arranged downstream of the compressor and in contact with the second heat medium circuit, as seen in the flow direction of the second heat medium, and is in heat exchange with the first heat medium in the first heat medium circuit;
8. H. a means for cooling and / or relaxing the first heat medium in the first heat medium circuit;
9. i. a fourth heat exchanger integrated into the second heat medium circuit, which is arranged there in front of the compressor as seen in the flow direction and which is in heat exchange connection with the first heat medium carried in the first heat medium circuit.

A special feature of this device according to the invention is that it does without any evaporator or condenser (liquefier), and instead has simple heat exchangers. This fact is made possible by the fact that none of the heat media used, neither the first heat medium nor the second heat medium, goes through a phase transition in the process.

The first heat exchanger, in which the first heat medium is brought into heat exchange with an ambient medium, can enable a heat transfer from, for example, the outside air, geothermal energy, from a liquid or from a gas to the first heat medium. This first heat exchanger can accordingly be operated in countercurrent and have two inputs and outputs, one each for the respective heat medium. The first heat exchanger can also be, for example, a lamellar heat exchanger with a fan for vehicles with only one input and one output for a single heat medium carried in a line system, e.g. a heat exchange between an environmental heat of the ambient air and the first heat medium for the To use heating and / or cooling of a vehicle interior.

The second heat exchanger can in turn be one that serves to exchange heat between the first heat medium and ambient air used for air conditioning, but also one that provides heat exchange between the first heat medium and another medium carried in a line system. In the latter case, the second heat exchanger can be a counterflow heat exchanger with two inlets and two outlets for the two media routed in pipe systems, or in the former case a lamellar heat exchanger with a fan, e.g. for vehicles (with only one inlet each) and output for the first heat medium) for the direct exchange of heat with air flowing into the vehicle interior.

In a second heat medium circuit sits a compressor, in particular a turbo-compressor, preferably a micro-turbo-compressor, which compresses the second heat medium, which flows through this circuit in gaseous form, and heats it accordingly. This compressor is operated when the device is used for heating or for warming the medium to be tempered. This compressor can then react to the outside temperature, in particular in a speed-controlled manner, whereby it generates a higher pressure ratio by setting a higher speed and thus higher temperatures of the compressed second heating medium (the opposite effect when reducing the speed).

In the third heat exchanger, the heat generated by the compressor in the second heat medium is transferred to the first heat medium when the system is operated as a heater. If the device is used for cooling (see further below), in the third heat exchanger, if this is not even completely decoupled by appropriate valves, only the first heat medium is passed through without any further heat transfer. In this case, the compressor usually does not run.

A fourth heat exchanger is provided in the device, which is integrated into the second heat medium circuit and is arranged there in front of the compressor, viewed in the flow direction, and which is in heat exchange connection with the first heat medium carried in the first heat medium circuit.

In this heat exchanger, a first heat transfer between the second heat medium and the first heat medium is already achieved before the second heat medium is heated by the compression. In this respect, this additional heat exchanger contributes to an increase in the efficiency in the heating operation of the device. If the device is to be used for cooling, this fourth heat exchanger has no function and, if necessary, can also be bridged with appropriate valves and line sections.

The means for cooling and / or relaxing the first heat medium in the first heat medium circuit ensures, in a known manner, that the first heat medium flowing back is cooled further, so that it can also be used when the device is operated as a heat pump in the heating mode Ambient temperature can absorb heat from the environment and thus make it available for heating. When the device is in operation for cooling, the means for cooling can be used in order to obtain a possibly further lowering of the temperature of the first heat medium for an improved cooling effect in the second heat exchanger.

The means for cooling can advantageously be a Peltier element, in particular a controllable Peltier element, or a plurality of such Peltier elements. Such an element can bring about a cooling effect independently of a pressure release, which is particularly advantageous for the operation of the device according to the invention for cooling, that is to say as an air conditioning system or cooling unit.

In particular, a liquid can be used as the first heat medium, in particular one which is liquid at normal pressure in any case in the temperature range from -50 ° C to + 60 ° C. Since the device according to the invention works without phase transitions in the first heat medium, it must be ensured that this medium maintains a uniform phase in the range of the corresponding operating temperatures. A liquid first heat medium is preferable to a gaseous one, since the heat storage capacity is significantly higher. Of course, liquids can also be used as the first heat medium which have a larger temperature range within which they remain liquid. For example, this temperature range can also be between -60 ° C and + 70 ° C, even beyond, for example between -90 ° C (or even lower, for example down to -135 ° C) and + 75 ° C or even + 125 ° C.

When choosing the first heating medium, in addition to the temperature range within which it safely maintains the phase, also the ability to absorb and store heat, especially also at low temperatures, e.g. environmental heat even at minus degrees, even in the deeper negative range (heat capacity ) as well as the ability to absorb or release heat quickly. It has proven to be suitable in this regard if a hydrofluoroether is used as the first heating medium. Hydrofluoroethers are chemical compounds of the empirical _{formula C x} F _{y -OC m} H _n , where x is a number from 1 to 12; y is a number from 0 to 25; m stands for a number from 1 to 12 and n stands for a number from 0 to 25. The corresponding compounds are formed from chains of different lengths of fully fluorinated carbons which are linked to an alkyl radical via an ether group. An example of a particularly suitable hydrofluoroether that uses as the first heating medium Ethoxynonafluorobutane (C ₄ F ₉ OC ₂ H ₅ ) should be mentioned. This is a clear, colorless liquid with a pour point (at normal pressure) of -138 ° C and a boiling point (at normal pressure) of 76 ° C. This material can be obtained in a quality that can be used as the first heat medium in the device according to the invention, for example from 3M Deutschland GmbH under the trade name 3M ™ Novec ™ 7200 High-Tech Liquid .

The group of substances claimed here is not harmful to the climate, so that its use is not only highly efficient from a technological point of view, but also harmless from an ecological point of view.

The second, gaseous heat medium can, in principle, take on very different forms, with air being considered to be very suitable here. Sufficient temperature control effects are achieved with air as the second heating medium; this medium is available everywhere "free of charge", so that the use of air does not mean any additional costs in production and operation. In addition, there are no possible environmental problems that could possibly arise when using another medium, in particular if this emerges from a closed circuit.

Advantageously, the fourth heat exchanger can have three separate line strands that are in heat exchange with one another, of which a first line strand belongs to the second heat medium circuit, a second line strand belongs to a first section of the first heat medium circuit and a third line strand belongs to a second section of the first heat medium circuit. In this embodiment, the fourth heat exchanger has three inputs and three outputs and - in heating mode - additionally uses the waste heat from the return of the first heat medium to preheat the first heat medium after the first heat medium has absorbed environmental heat in the first heat exchanger and before it is further heated in the third heat exchanger by the compression heat generated in the second heat medium circuit after the compressor. The fourth heat exchanger is used for this also the cooling of the second heating medium in the second heating medium circuit.

In particular, if a further reduction of the pressure in the first heat medium circuit is necessary, this also contributes to a further cooling of the first heat medium on the route of the return to the first heat exchanger, an, in particular controllable, expansion valve can be used in the second section of the first heat medium circuit be arranged.

The first conveying means for moving the first heat medium can in particular be a circulating pump, which can in particular be designed to be controllable.

The first conveying means, for example a circulating pump, can in particular be designed to be reversible in its conveying direction in order to convey or move or drive the first heat medium in two directions, clockwise and counterclockwise rotation through the closed first heat medium circuit. This fact of the possibility of either clockwise or counterclockwise rotation is of particular importance for the option of optional operation of the device as a heating device (heat pump) or as a cooling device (air conditioning, cooling unit).

The method according to the invention for temperature control of a medium is accordingly characterized in that a first heat medium is guided in a first closed heat medium circuit and is kept in circulation therein by a first conveying means in order to absorb and release heat, the first heat medium in the first heat medium circuit by a first heat exchanger is performed to exchange heat with an ambient medium. Furthermore, the first heat medium is passed through a second heat exchanger for exchanging heat with the medium to be tempered, the first heat medium being passed in the first heat medium circuit without going through phase transitions in the first heat medium circuit. In order to heat the medium to be tempered, the first heat medium is transferred from the conveying means through the first heat exchanger led to absorb heat there. After flowing through the first heat exchanger, the first heat medium is passed through a third heat exchanger, which is integrated in a second closed heat medium circuit in which a second, gaseous heat medium is circulated without phase transitions. In this case, a compressor is arranged in the second heat medium circuit, which is arranged upstream of the third heat exchanger, viewed in the direction of flow of the second heat medium, and which compresses and heats the second heat medium. The first heat medium then absorbs heat from the second heat medium in the third heat exchanger and, after passing through the third heat exchanger, is passed through the second heat exchanger. There the first heat medium gives off heat to the medium to be tempered. Finally, after flowing through the second heat exchanger, the first heat medium is expanded and / or cooled and returned to the first heat exchanger.

This method can, and is preferably, carried out in a device as described and explained above. In the procedure described above, the device works as a heat pump, that is, a method for heating a useful medium is operated.

According to the invention, after flowing through the second heat exchanger and before flowing through the first heat exchanger again, the first heat medium is passed through a fourth heat exchanger, which is integrated into the second heat medium circuit and through which the second heat medium flows before it is compressed by the compressor. Through this fourth heat exchanger, the first heat medium is also guided in a further section of the first heat medium circuit, namely after flowing through the first heat exchanger and before flowing through the third heat exchanger. In this further section of the first heat medium circuit in this fourth heat exchanger, heat is generated both from the second heat medium (before compression) and from the first returned in the section between the second heat exchanger and the first heat exchanger in the direction of the first heat exchanger Heat medium added. This design of the method according to the invention increases the efficiency of the method or of the device operated in this way when it is used as a heat pump, since the otherwise uselessly dissipated residual heat is still fed into the operating cycle.

In the embodiment as described above, the first heat medium can also be expanded and / or cooled between leaving the fourth heat exchanger and before being fed back to the first heat exchanger. This can be done, for example, with the aid of Peltier elements, but also, for example, using an expansion valve in or in contact with the corresponding line.

The method according to the invention can, however, optionally not be used for heating, that is to say for operating the device in the manner of a heat pump, but can also be used for cooling the medium to be tempered. The conveying direction of the conveying means and thus the flow direction of the first heat medium is reversed, with the second heat medium circuit being interrupted and / or decoupled to the extent that heat transfer no longer takes place between the second heat medium and the first heat medium. The first heat medium is then passed through the second heat exchanger in order to absorb heat there from the medium to be tempered and thus to cool this medium to be tempered. The first heat medium then flows through the third heat exchanger without undertaking any further heat exchange there, or flows past it, and then flows through the first heat exchanger in order to give off heat to the environmental medium there. The first heat medium is then returned to the second heat exchanger for renewed absorption of heat from the medium to be tempered. Here, too, the first heat medium runs through this cycle without phase transitions.

In this variant of the method, a special feature of the method according to the invention can be seen, which is also shown as a special feature of the device according to the invention or a use thereof. Because here can be one and the same Device can be used both as a heat pump for heating purposes and for cooling a medium, for example as an air conditioning or cooling unit, by reversing the conveying direction of the first heat medium as described.

This design is of great interest, inter alia, in the field of the automotive industry, where such a device can be used both for heating and for air-conditioning cooling of a passenger compartment in an automobile. In particular, where, for example, the heat energy released by the use of highly efficient combustion engines is no longer available in sufficient quantities to heat the passenger compartment, or in the case of electric vehicles whose drive type no longer releases any significant heat energy and makes it usable, are for operation of the vehicle to provide alternative heating options at cold ambient temperatures, for which the device according to the invention and the method according to the invention are particularly suitable, since they also offer a cooling option in addition to a heating option by simply reversing and redesigning the circuit of the first heating medium. This application is also of great advantage e.g. in the area of air conditioning (heating / cooling) of passenger compartments in rail wagons and also in other means of transport, buildings and rooms, mobile homes and mobile homes or in machines and systems.

If the method is used for cooling as described above, it may be necessary - depending on the weather conditions and outside temperature and depending on the desired temperature setting for the area to be cooled - to intervene with active cooling of the first heating medium, for which the first heating medium in a section of the first heat medium circuit in the flow direction after the first heat exchanger and before the second heat exchanger can be actively cooled, for example with the aid of a Peltier element or with the aid of several such elements. In the case of the Peltier elements then used, which are operated with electrical energy, there is also a warm side of the element in addition to the cold side used for cooling, at which heat has to be dissipated in order to be able to continue operating the Peltier element with a cooling effect. This heat can advantageously be dissipated to an environmental heat medium and thus added to the environmental heat. For this purpose, air can be used to cool the Peltier element on its warm side, for example with a fan or simply via a flow channel (for example charged by the wind of a vehicle equipped with the device according to the invention). However, a further circuit with a heat medium can also be formed, which absorbs the waste heat from the Peltier elements and in turn emits it to an environmental medium, for example via a heat exchanger. This cycle can also be flowed through directly by such an environmental medium (e.g. air, but also a heat medium connected to geothermal energy.

In the context of the method, the first heat medium used is preferably one as has already been described above for the device, so that reference can be made to the above description with regard to the preferred selection of this first heat medium.

The device according to the invention and the method according to the invention can be used and applied in a variety of ways, for example for heating or cooling buildings, in particular for residential and utility buildings, as heating and air conditioning for the automotive industry, for the transport and logistics industry, for buses and coaches Railway, for machine and plant construction, but also for use in household appliances.

Fig. 1

eine schematische Darstellung einer Vorrichtung zum Temperieren eines Mediums in einer ersten möglichen Ausgestaltung der Erfindung und mit einer Veranschaulichung des Verfahrensablaufs;

Fig. 2

eine schematische Darstellung einer Vorrichtung zum Temperieren eines Mediums in einer zweiten möglichen Ausgestaltung der Erfindung und mit einer Veranschaulichung des Verfahrensablaufs; und

Fig. 3

eine schematische Darstellung eines Ausschnitts der Vorrichtung entsprechend der Darstellung in Fig. 2 mit der Veranschaulichung einer aktiven Kühlung der Peltierelemente.

Further advantages and features and advantages of the invention emerge from the following description of an exemplary embodiment on the basis of the attached figures. Show:

Fig. 1

a schematic representation of a device for temperature control of a medium in a first possible embodiment of the invention and with an illustration of the process sequence;

Fig. 2

a schematic representation of a device for temperature control of a medium in a second possible embodiment of the invention and with an illustration of the process sequence; and

Fig. 3

a schematic representation of a section of the device corresponding to the representation in FIG Fig. 2 with the illustration of an active cooling of the Peltier elements.

In the figures, possible implementations of a device according to the invention for controlling the temperature of a medium are sketched in basically two configurations that are slightly modified from one another. In addition, in Fig. 3 outlines a further modification that can be selected for both of the basic design variants shown in the preceding figures. The figures also contain representations that illustrate the process sequence of a method according to the invention to be operated on these devices.

In Figure 1 First of all, a first heat exchanger 1 is shown, which in this embodiment is a heat exchanger that provides a heat transfer between a gaseous environmental medium and a circulating heat medium guided in a line 2. The first heat medium is guided in a first circuit 3. The line 2 in the heat exchanger 1 is connected to a pipe section 4, which is part of a feed line to a second heat exchanger 5, which in turn is traversed by the first heat medium in a line 6 and serves to exchange heat between this first heat medium and a gaseous medium.

In the supply line, a further heat exchanger 7 is arranged, starting from the first heat exchanger 1 behind the pipe section 4, through which the heat medium supplied in the pipe section 4 flows and which the heat medium leaves again via a further pipe section 8. The heat exchanger 7 can also be flowed through in the opposite direction, as will be explained later. The pipe section 8 is then connected to a further heat exchanger 9, through which the heat medium flows to an adjoining pipe section 10, which then opens into the second heat exchanger 5, is connected to the line 6 in this heat exchanger 5. Another pipe section 11 is on an opposite side with the heat exchanger 5, more precisely with the line 6, and leads to a circulating pump 12. In a pipe section 13 adjoining the circulating pump 12, two switchable 3-way valves 14, 15 are arranged. In separate switching positions, these allow the flow of the first heat medium either to be routed via a supply line 16 through the heat exchanger 7 and back via a discharge line 17 in which a controllable expansion valve 18 is provided to the pipe section 13 or by bypassing this loop through the heat exchanger 7 directly further in the pipe section 13. Seen from the circulating pump 12 beyond the 3-way valves 14, 15 there is at least one controllable Peltier element 19; several such elements can also be provided. The pipe section 13 then opens again into the line 2 of the heat exchanger 1 and thus closes the circuit 3.

In the in Figure 1 A further circuit 20 is realized in the illustrated device, in which a second heat medium circulates. Here, the second heat medium flows through the heat exchanger 7, then enters a pipe section 21 and is compressed by a turbo-compressor (in particular a micro-turbo-compressor) 22, guided via a pipe section 23 to the heat exchanger 9 and then back to the heat exchanger 7 via a return line 24 .

The one in the Figure 1 The device shown can now be operated in two modes, namely once as a heat pump to heat a useful medium passed through the heat exchanger 5, and another time as an air conditioning device (air conditioning) to cool a useful medium passed through the heat exchanger 5.

In the following, the use as a heat pump is first described, in which the circulating pump 12 is the first heat medium in the circuit 3 in the illustration of FIG Figure 1 can circulate clockwise.

The operating direction of the heat media in the heat medium circuits 3 and 20 is illustrated by the filled arrows in the first circuit 3 and by the arrows outlined with dashed lines in the second circuit 20.

In this mode of operation, environmental heat (e.g. from outside or exhaust air) is transferred to the first heat medium in the first heat exchanger 1 when it passes through line 2. The first heat exchanger 1 can in particular be a lamellar heat exchanger with a fan 25.

The first heat medium is transported clockwise by the circulation pump 12 in the closed heat medium circuit 3 and brings the absorbed environmental heat to the heat exchanger 7.

In the heat exchanger 7, the first heat medium is increased in its temperature level by the waste heat that comes from the return from the heat exchanger 5, as well as by the cooling of the second heat medium from the second circuit 20. In practice, for example, the temperature level can be increased to approx. 30 ° C if the temperature of the second heating medium in the return is cooled down to approx. 30 °. For this purpose, the 3-way valves 14, 15 are each in a switching position in which the supply line 16 and the discharge line 17 are also integrated into the circuit 3.

The second heat medium, cooled down (for example to approx. 30 ° C.), is sucked in, compressed and again in the self-contained second circuit 20 in a diabatic process by the speed-controlled turbo-compressor 22, which can in particular be a micro-turbo-compressor brought to a high temperature level, so-called compression heat is impressed on it.

The second heat medium heated in this way meets the first heat medium again in the heat exchanger 9, which is routed around the turbo compressor in the pipe section 8, and heats the first heat medium to a usable temperature.

The heated first heat medium flows to the heat exchanger 5, which in this exemplary embodiment can be a lamellar heat exchanger with a fan 26. In this heat exchanger 5, the first heat medium transfers this heat to a useful medium, e.g. fresh air that is sucked in.

The first heat medium comes from the heat exchanger 5 and flows through the 3-way valve 14 to use the waste heat to the heat exchanger 7.

The first heat medium, cooled to about 10 ° C, for example, then comes to the controllable Peltier elements 19 via the 3-way valve 15. On the Peltier elements 19, the Peltier effect reduces the temperature of the heating medium to approximately 10K below the ambient heat. The heat generated during cooling on the other side of the Peltier element can advantageously also be used to preheat the ambient heat. The energetic use of the Peltier elements 19 is then optimally used. The Peltier elements 19 can be regulated and thus the desired temperature range can be set.

After cooling by the controllable Peltier elements 19, the first heat medium comes back to the heat exchanger 1. The cycle can start again. It is important to mention that the first heating medium does not undergo any phase transitions during the entire cycle. Rather, the first heat medium is a liquid that remains liquid under all conditions occurring in the course of the first circuit 3. The first heating medium is in particular a hydrofluoroether, for example ethoxynonafluorobutane (C ₄ F ₉ OC ₂ H ₅ ).

The second heating medium does not undergo a phase change either, but remains gaseous during the entire passage of the second circuit 20.

As already mentioned, after the in Figure 1 The scheme shown can be operated not only as a heat pump, but also for cooling or air conditioning a useful medium.

The device is operated as follows; this operation is represented by the open arrows outlined in solid lines in the figure.

When the device is operated as an air conditioning system, the second circuit 20 is deactivated; the turbo compressor 22 is not required for cooling and therefore remains out of operation.

In such an operation of the device as an air conditioning system, the environmental medium (e.g. outside or exhaust air) is preferably colder than the first heat medium, so that the first heat medium in the heat exchanger 1 transfers heat to the environmental medium. However, the device also functions when the environmental medium is warmer than the first heat medium when it flows through the heat exchanger 1 in the line 2.

After the absorption of environmental heat or the release of heat to the environmental medium by the heating medium, this flows through the controllable Peltier elements 19 for any further cooling that may be required can flow through in the opposite direction. For this purpose, the circulation pump 12 is designed to be reversible in its conveying direction. The first heat medium is transported by the circulating pump 12 here in the counterclockwise direction in the circuit 3 in the representation of the figure.

A controller regulates the use of energy by the Peltier elements 19 preferably in such a way that a difference between the temperature of the environmental medium and the temperature of the first heating medium is approximately 10 K, for example.

After the temperature reduction, the first heat medium flows through the two 3-way valves 14, 15, which are switched so that the heat medium is passed on directly into the pipe section 11 without going to the heat exchanger 7 to arrive. The first heat medium therefore reaches the heat exchanger 5 directly.

In this heat exchanger 5, the heat medium absorbs heat from the useful medium and cools it down in the process. This useful medium can be used in the device Figure 1 in particular be sucked in and cooled fresh air, which then reaches the rooms to be air-conditioned, for example the passenger compartment of a vehicle.

The first heat medium exits the heat exchanger 5 at a higher temperature than it entered this heat exchanger 5 and flows to the heat exchanger 9. The first heat medium flows through this heat exchanger 9 and on to the heat exchanger 7 without any further heat exchange routed around the turbo compressor 22 in the pipe section 8.

The first heat medium now flows through the heat exchanger 1 again and gives off heat there, provided it is at a higher temperature level than the ambient temperature, and the cycle then begins again.

It is also possible to provide a further pipeline section, which can be switched alternatively, in particular via valves, in which the first heat medium passes directly from heat exchanger 5 to heat exchanger 1, thereby bypassing heat exchangers 7 and 9, which in this operating mode do not make any functional contribution anyway to the cooling process.

In Figure 2 a device, which is basically identical in construction and operates according to the same principle, is sketched, so that reference can be made to the above description. The only difference in the representation in Figure 2 to those in Figure 1 is that the in Figure 1 shown heat exchangers 1 and 5 in the structure according to Figure 2 have been replaced by heat exchangers 1 'and 5', the heat exchangers 1 'and 5' now being those that are also connected to a line system on the input or output side and not, for example, as fins of Air can flow through freely. Of course, one of the line systems in this heat exchanger can also have a gaseous medium, for example air, flowing through it, in particular line 27 or line section 28 Transport of geothermal energy is fed to the heat exchanger 1 'in a line 27 and a heating medium, for example water, is heated in a line section 28 of a heating circuit with the heat exchanger 5'. In the case of reverse operation as described above, air conditioning (cooling) of living spaces can also be provided here.

In Figure 3 is finally shown by the representation of a section or a partial section of the illustration according to Figure 2 a variant is shown in which - if the device is used for air conditioning (cooling) - the Peltier elements 19 are actively cooled on their heat-emitting side. Such active cooling can be necessary in particular when the ambient temperature is particularly high. If the device is used, for example, in the context of a vehicle, the airflow may be sufficient to dissipate the heat released by the Peltier elements in their respective heat-emitting part. This can be more difficult with stationary systems.

A fan 29 can initially be provided for this purpose. If the provision of such a fan 29 is sufficient to adequately cool the Peltier element (s) on the heat-emitting sides, no further cooling measures are required. If the supply of fresh air by means of the fan 29 alone is not sufficient, a further cooling mechanism can additionally or alternatively be provided, for example one such as is shown in FIG Figure 3 is sketched.

Cooling with the aid of a heating medium is provided there, the first heating medium from the heating medium circuit 3 being used in this embodiment.

Heat medium flowing in a feed line 30 absorbs waste heat from the Peltier element (s) 19. A circulation pump 31 then conveys the heat medium in the direction of a 3-way valve 32. The 3-way valve 32 can be connected to the supply line 16. If the 3-way valve 32 is connected to the supply line 16 in the cooling mode of the device, this supply line 16 is separated from the line formed by the pipe sections 11 and 13 by means of the 3-way valve 14. As a result, after flowing through the 3-way valve 32, the first heat medium is passed on via the supply line 16 to a further 3-way valve 33. In this operating mode, this blocks the supply line 16 from the heat exchanger 7 and transfers the flow of the first heat medium instead into a short-circuit line 34. This is connected to a further 3-way valve 35, which is connected to the discharge line 17. In this operating mode, the 3-way valve 35 blocks the discharge line 17 from the heat exchanger 7 and conducts the first heat medium to the expansion valve 18. There the first heat medium is expanded and thereby cooled. Via a further 3-way valve 36 connected downstream of the expansion valve 18, which blocks the discharge line 17 from the 3-way valve 15 in this operating mode, the thus cooled and pressure-relieved heat medium is then transferred to a 3-way valve 36 connected return line 37 and from there back to the Peltier elements 19, where it again absorbs waste heat in order to then get back into the flow line 30. This circuit is activated by connecting the corresponding 3-way valves 32, 33, 35 and 36 by a control when the device is working in the cooling mode and active cooling of the Peltier elements 19 is required.

Of course, as a person skilled in the art will readily recognize, a corresponding line and valve arrangement and wiring can also be used in the case of the in Figure 1 shown embodiment of a device according to the invention are implemented.

It is also possible to operate active cooling of the Peltier element (s) 19, as described above, also in heat pump operation, if, for example, the first heat medium has to be cooled down particularly far in order to be in the heat exchanger 1 or 1 'to be able to absorb environmental heat at a low temperature level. In such a case, the short-circuit line 34 is then typically not used, the 3-way valves 33 and 35 can be switched in such a way that the heat exchanger 7 remains integrated in the circuit. In addition, in such a circuitry, the 3-way valves 14 and 15 are also switched in such a way that they include the supply line 16 and the discharge line 17. The 3-way valves 32 and 36 are then switched in such a way that they open both a connection to the 3-way valves 14 and 15 and the connection in the direction of the circulating pump 31 or the return line 37. The 3-way Valve 32 must also have a non-return valve so that the first thermal fluid pressed in from the supply line 16 from the 3-way valve 14 by means of the circulation pump 12 cannot flow into the 3-way valve 32 in the direction opposite to the intended direction of circulation.

Also here are in the Figure 3 for the first cooling medium circuit 3, the flow directions and courses of the first cooling medium for the case of operation as heating (heat pump) or as cooling (for air conditioning) are indicated by arrows, as can be seen from the legend arranged in the figure.

A special feature of the invention consists in the selection of the first heating medium. As already mentioned, this is preferably a hydrofluoroether (a chemical compound of the empirical _{formula C x} F _{y -OC m} H _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 present as a liquid under normal conditions. They typically only have their pour point 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 the pour point and boiling point. The densities of these liquids are significantly higher than the heat media used by known and corresponding devices. This medium is also electrically non-conductive, so that it can serve as a cooling medium for cooling the Peltier elements 19 to which electrical voltage is applied, in the manner described above, without leading to a short circuit or the like.

The global warming potential (GWP) of corresponding compounds is also very clearly, between 5 days and 4.9 years, below the GWP of previously used heating media. Hydrofluoroethers are compatible with many metals, plastics and elastomers and thus allow the use of cheaper and smaller components in the implementation of devices operated with these media.

In contrast to the previously used heating media, hydrofluoroethers are not dangerous goods and therefore do not have to be specially treated in accordance with the legislation during transport, assembly, repair or service, dismantling and in the event of accidents. Rather, they are correspondingly easier, more environmentally friendly and risk-free to handle and use.

Hydrofluoroethers are also non-electrically conductive, non-combustible and flammable and can therefore also be used where there is a risk of fire in the event of an accident, short circuits in the electrical system or environmental hazards could arise.

A harmless, gaseous heat medium, for example air, can be used in the second heat medium circuit.

The turbo compressor in the second heat medium circuit can work with a pressure of only up to 4 bar and still achieve sufficient heating of the second heat medium. The comparatively low pressure significantly reduces the risk of accidents, leaks and environmental hazards.

In the second heat medium circuit, only a small volume of the second heat medium is required. Furthermore, there is only a low pressure there and, in addition, a preheated second heating medium before entering the turbo compressor, so that the required electrical power in the heat pump operation of the device is very low. A further reduction in the required electrical power can even be achieved if the turbo compressor is equipped with gas or magnetic bearings.

Advantages of turbo-compressors, in particular the preferred micro-turbo-compressors, are, among other things, that only very low mechanical losses occur and thus a very high level of efficiency is achieved. Turbo compressors can be regulated very well. A very wide range of services can be covered with them. In contrast to the scroll compressors customary in known devices, the turbo compressors are distinguished by the fact that there is no pressure pulsation. The use of a lubricant, such as oil in the scroll compressors, is also not necessary with the turbo compressors. They have - especially as micro-turbo compressors - very small dimensions. E.g. a 5,000 W micro-turbo compressor has the dimensions: length 25.4 cm, diameter 8.0 c. For comparison: A scroll compressor with the same output has the following dimensions: length 60.0 cm and diameter 40.0 cm. As a result, the turbo compressors are also very light compared to the scroll compressors that have been used up to now. Turbo compressors are practically maintenance-free and therefore have extremely low operating costs. The service life of these compressors is many times longer than that of scroll compressors.

Micro turbo compressors can have the disadvantage that the very high speeds of the impeller shaft (up to 500,000 rpm in peak load, normally between 80,000 rpm to 180,000 rpm) can lead to noises, which can, however, be controlled .

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

List of reference symbols

1, 1 '

Heat exchanger

2

management

3

first cycle

4th

Pipe section

5, 5 '

Heat exchanger

6th

management

7th

Heat exchanger

8th

Pipe section

9

Heat exchanger

10

Pipe section

11

Pipe section

12th

Circulation pump

13th

Pipe section

14th

3-way valve

15th

3-way valve

16

Supply line

17th

Derivation

18th

Expansion valve

19th

Peltier element

20th

second cycle

21

Pipe section

22nd

Turbo compressor

23

Pipe section

24

Return line

25th

Fan

26th

fan

27

management

28

Line section

29

Fan

30th

Flow line 3-way valve

31

Circulation pump

32

3-way valve

33

3-way valve

34

Short circuit line

35

3-way valve

36

3-way valve

37

Return line 3-way valve

Claims (15)

1. A method of controlling the temperature of a medium, wherein a first heat medium is passed in a first closed heat medium circuit and is kept circulating therein by a first conveying means to receive and release heat, wherein the first heat medium is guided in the first heat medium circuit through a first heat exchanger for exchanging heat with an ambient medium and wherein the first heat medium is guided through a second heat exchanger for exchanging heat with the medium to be tempered, wherein the first heat medium is guided in the first heat medium circuit without undergoing phase transitions in the first heat medium circuit, in that, for heating the medium to be tempered, the first heat medium is passed by the conveying means through the first heat exchanger in order to absorb heat there, in that, after flowing through the first heat exchanger, the first heat medium is passed through a third heat exchanger which is incorporated in a second closed heat medium circuit, in which a second, gaseous heat medium is guided in a circuit without phase transitions, a compressor being arranged in the second heat medium circuit, which compressor is arranged upstream of the third heat exchanger, as seen in the direction of flow of the second heat medium, and compresses and heats the second heat medium, the first heat medium in the third heat exchanger taking up heat from the second heat medium, in that the first heat medium, after passing through the third heat exchanger, is guided through the second heat exchanger, in which it gives off heat to the medium to be tempered, and in that the first heat medium, after flowing through the second heat exchanger, is expanded and/or cooled and returned to the first heat exchanger, characterised in that the first heat medium, after flowing through the second heat exchanger and before flowing through the first heat exchanger again, is passed through a fourth heat exchanger which is incorporated in the second heat medium circuit and through which the second heat medium flows before it is compressed by the compressor, and through which the first heat medium is passed in a further section of the first heat medium circuit, namely after flowing through the first heat exchanger and before flowing through the third heat exchanger, wherein the first heat medium in said further section of the first heat medium circuit in said fourth heat exchanger receives heat both from the second heat medium and from the first heat medium recirculated towards the first heat exchanger in the section between the second heat exchanger and the first heat exchanger.
2. A method according to claim 1, characterised in that the first heat medium is expanded and/or cooled between leaving the fourth heat exchanger and before being fed to the first heat exchanger again.
3. A method according to one of the preceding claims, characterised in that, for cooling the medium to be tempered, the conveying direction of the conveying medium and thus the flow direction of the first heat medium is reversed, at the same time the second heat medium circuit being interrupted and/or disconnected, the first heat medium being passed through the second heat exchanger in order to absorb heat there from the medium to be tempered, then flows through the third heat exchanger without carrying out a further heat exchange there, or is guided around this third heat exchanger, then flows through the first heat exchanger in order to give off heat there to the environmental medium, and is then returned to the second heat exchanger for renewed absorption of heat from the medium to be tempered, the first heat medium passing through this circuit without phase transitions.
4. A method according to claim 3, characterised in that the first heat medium is actively cooled in a section of the first heat medium circuit in the direction of flow downstream of the first heat exchanger and upstream of the second heat exchanger.
5. A method according to one of the preceding claims, characterised in that a liquid is used as the first heat medium, which is liquid at normal pressure in any case in the temperature range from -50°C to + 60°C.
6. A method according to any one of the preceding claims, characterised in that a hydrofluoroether is used as the first heat medium.
7. A device arranged for carrying out a method of tempering a medium according to any one of the preceding claims, having the following components:

   a. a first closed heat medium circuit (3) in which a first heat medium circulates, the first heat medium being selected to circulate in the first heat circuit without phase transitions,

   b. a second closed heat medium circuit (20) in which a second gaseous heat medium circulates, the second gaseous heat medium being selected to flow through the second heat medium circuit without phase transitions,

   c. a first heat exchanger (1; 1') arranged in the first heat medium circuit (3), in which the first heat medium can be brought into heat exchange with an ambient medium,

   d. a second heat exchanger (5; 5') arranged in the first heat medium circuit (3), in which the first heat medium can be brought into heat exchange with the medium to be tempered,

   e. a first conveying means (12) arranged in the first heat medium circuit (3) for moving the first heat medium in the first heat medium circuit (3),

   f. a compressor (22) arranged in the second closed heat circuit (20) for compressing the second, gaseous heat medium,

   g. a third heat exchanger (9), which is arranged downstream of the compressor (22), as seen in the direction of flow, and in contact with the second heat medium circuit (20) and is in heat exchange with the first heat medium in the first heat medium circuit (3),

   h. a means (18, 19) for cooling and/or expanding the first heat medium in the first heat medium circuit (3), characterised in that

   i. a fourth heat exchanger (7) is provided, which is integrated into the second heat medium circuit (20) and is arranged there upstream of the compressor (22), as seen in the direction of flow, and which is in heat exchange connection with the first heat medium conducted in the first heat medium circuit (3).
8. A device according to claim 7, characterised in that a liquid is used as the first heating medium, which liquid is liquid at normal pressure at least in the temperature range from -50°C to +60°C.
9. A device of any one of claims 7 or 8, characterized in that the first heat medium is a hydrofluoroether.
10. A device according to any one of claims 7 to 9, characterised by at least one Peltier element (19) as means for cooling the first heat medium. heat medium.
11. A device according to any one of claims 7 to 10, characterised in that the fourth heat exchanger (7) comprises three mutually heat exchanging separate conduits, a first conduit belonging to the second heat medium circuit (20), a first conduit belonging to the second heat medium circuit (20), a second conduit belonging to a first portion (4, 21) of the first heat medium circuit (3) and a third conduit (16, 17) belonging to a second portion of the first heat medium circuit (3).
12. A device according to claim 11, characterised in that the second section of the first heat medium circuit, to which the third pipe run (16, 17) belongs, can be incorporated into the first heat medium circuit (3) via corresponding valves (14, 15) or separated and bridged from it.
13. A device according to one of claims 11 or 1 2, characterised in that an, in particular controllable, expansion valve (18) is arranged in the second section (16, 17).
14. A device according to any one of claims 7 to 13, characterised in that the first conveying means (12) is reversible with respect to the conveying direction.
15. A device according to any one of claims 7 to 14, characterised in that the compressor (22) is a turbocompressor.

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