EP3163036B1 - Functional synergies of thermodynamic circuit processes and heat sources - Google Patents

Description

Field of the invention

The invention relates to a system for heat utilization comprising a heat source and a cooling device for removing heat from the heat source, the cooling device comprising: a cooler for transferring heat to an ambient medium, in particular wherein the cooler is an air cooler and the surrounding medium is air; and a thermodynamic cycle apparatus, particularly an ORC apparatus, having a working medium, an evaporator for evaporating the working medium by transferring heat of the heat source to the working medium, an expansion device for generating mechanical energy, and a condenser for condensing the working medium expanded in the expansion device. Furthermore, the invention relates to a corresponding method for removing heat from a heat source with a cooling device.

State of the art

An economical solution for increasing the efficiency of high potential combustion engines, particularly in trucks, is the use of waste heat from the internal combustion engine with a thermal cycle (e.g., Organic Rankine Cycle System, ORC system). Some of the requirements or given conditions here are low additional costs, less space available, little intervention and influence on the other system. It is therefore useful or necessary to exploit synergies with existing components.

If a force-generating process, such as the Organic Rankine Cycle (ORC), operated in the environment of an internal combustion engine, is still both the direct integration of the generated energy as mechanical performance in the system (eg, the expansion engine of the ORC system can support the combustion engine drive), as well as their provision for ancillaries often advantageous because it comes in the conversion of mechanical energy into electrical energy to conversion losses. In addition, eliminated by the motors for drive or generators for downforce also costs and the compactness can be increased, both of which are critical factors for the integration of a force-generating process in the said environment. In addition, the expansion machine can also drive a generator, wherein the electrical energy generated thereby can be used to drive one or more components in the environment of the internal combustion engine. In this context, the hybridization is called, so the direct or indirect use of electrical energy generated in the drive train of the engine. For example, one or more electric motors supplied with the generated electrical energy may be provided in a truck for driving one or more drive shafts.

The document US 2015/276284 A1 discloses a cooling device for a condenser of a system for a thermodynamic cycle in an arrangement with an internal combustion engine.

The document US 2013/312418 A1 discloses a system for converting thermal energy into mechanical energy in a vehicle.

Description of the invention

The object of the invention is to provide synergies in the use of heat from heat sources.

The object is achieved by a system according to claim 1.

The system according to the invention comprises a heat source and a cooling device for removing heat from the heat source, the cooling device comprising: a cooler for transferring heat to an ambient medium, in particular wherein the cooler is an air cooler and the surrounding medium is air; and a thermodynamic cycle device, particularly an ORC device, having a working fluid, an evaporator for evaporating the working fluid by transferring heat from the heat source to the working fluid, an expansion device for generating mechanical energy, and a condenser for condensing the working fluid expanded in the expansion device; wherein the cooling device further comprises a condenser cooling fluid circuit for removing heat from the condenser thermodynamic cycle apparatus via the radiator. This embodiment of the system according to the invention allows the shared use of the existing radiator for the heat dissipation from the condenser of the thermodynamic cycle device, in particular for the heat removal from the ORC capacitor. The cooling fluid may in particular be or comprise water, preferably with a proportion of antifreeze. The heat source may be, for example, an internal combustion engine.

The system of the invention is configured such that the cooling device further comprises a heat source cooling fluid circuit, wherein a first branch of the heat source cooling fluid circuit passes through the evaporator for transferring heat to the working fluid. In this way, the heat in the cooling circuit of the heat source can be introduced into the thermodynamic cycle.

The inventive system is configured such that the heat source cooling fluid circuit in the direction of flow of a cooling fluid before the evaporator comprises a first branch into a second branch of the heat source cooling fluid circuit for bypassing the evaporator and merging of the second branch with the first branch after the evaporator the second branch comprises a first valve, preferably a controlled valve. Thus, the exit temperature of the cooling fluid (in particular engine cooling water) is set to a higher value via the valve than in the usual operation according to the prior art. The increase in temperature results in a higher power of the thermodynamic cycle.

A development consists in that the heat source cooling fluid circuit in the flow direction of the cooling fluid before the evaporator comprises a second branch into a third branch of the heat source cooling fluid circuit, and wherein the third branch is adapted to cooling fluid through the radiator and back into the first branch lead, wherein the second branch preferably a second valve, in particular a three-way valve comprises. In this way, a runflat capability of the system is provided. Such run-flatness can be due to failure of the thermodynamic cycle process due to overheating of the temperature of the heat source insufficient heat absorption by the thermodynamic cycle may be required. If the heat transfer capacity of the radiator is insufficient and / or if no or insufficient cooling of the cooling fluid takes place in the evaporator, cooling fluid can be passed directly to the radiator via the second valve. As a result, the temperature of the cooling fluid supplied to the radiator increases, the logarithmic temperature difference increases, and more heat is transferred.

According to another embodiment, the heat source cooling fluid circuit in the flow direction of the cooling fluid downstream of the evaporator may comprise a third branch into a fourth branch of the heat source cooling fluid circuit, the fourth branch being adapted to guide cooling fluid through the cooler and back into the first branch. wherein the third branch preferably comprises a third valve, in particular a three-way valve, wherein a combination of the fourth branch is provided in the third branch in combination with the previous development. These advantages of this development are analogous to those of the previous development, it is only branched off after the evaporator, so that a more moderate heat extraction than before the evaporator is possible. When combining both developments, both valves can be opened simultaneously.

Another development consists in that the heat source cooling fluid circuit in the flow direction of the cooling fluid in front of the radiator comprises a merging of the third and fourth branch with the condenser cooling fluid circuit. In this way, a simple interconnection of the heat source cooling fluid circuit with the condenser cooling fluid circuit is provided. A disadvantage, however, is that the condenser of the thermodynamic cycle device is also flowed through by relatively hot cooling fluid, which has a negative effect on the performance of the expansion device.

In another embodiment, the radiator may include an input header, an output header, and intermediate channels interconnecting respective opposite portions of the input header and the output header, one input of the condenser cooling fluid loop into the input header and an input of the third and fourth Branches of the heat source cooling fluid circuit are spaced apart in the input header, in particular at respective end portions of the input header are arranged, and wherein an output of the condenser cooling fluid circuit from the output collector and an output of the third and fourth branch of the heat source cooling fluid circuit from the output collector are spaced from each other, in particular at respective End regions of the output collector are arranged, wherein the input and output of the condenser cooling fluid circuit and the heat source cooling fluid circuit are arranged at respectively opposite areas of the input collector and the output collector.

In this way, a division of the existing radiator surface into a high-temperature region (cooling fluid of the heat source) and a low-temperature region (cooling fluid for the condenser of the thermodynamic cycle device) is made possible. Thus, the capacitor as low as possible temperature can be made available and the discharge of excess heat of the cooling fluid of the heat source to a high temperature level happen, which has a positive effect on the heat dissipation through the radiator to the environment. The distribution of the mass flows in partial mass flows to the terminals of the input collector and thus also through the radiator surface is preferably carried out via the second and / or third valve. Adjusting the proportions of the hot or cold radiator surface takes place automatically in this interconnection depending on the partial mass flows.

Another development is that the cooling device further comprises at least one heat exchanger for transferring heat in exhaust gas of the heat source to the heat source cooling fluid circuit. Thus, the heat in the exhaust gas of the heat source can be used. In addition, the sound-absorbing property of a Abgaswärmeübertragers can be used to reduce the actual muffler or completely replace. Other sources of heat that can be used are other heat fluxes bound to mass flows, such as e.g. hot gas mass flows.

According to another embodiment, the system further comprises a generator, with the mechanical energy generated by the expansion device in electrical Energy is convertible. The generated electrical energy may be used to operate electrical components in the system or to be fed into an electrical grid.

Another development consists in that mechanical energy generated by the expansion device can be used via a respective electrical, mechanical or hydraulic coupling for (a) driving a fan of the condenser and / or a fan of the radiator; and / or (b) driving a circulation pump in the heat source cooling fluid circuit and / or a feed pump of the thermodynamic cycle device and / or a circulation pump in the condenser cooling fluid circuit and / or a water pump and / or a hydraulic pump and / or an oil pump; and / or (c) driving an alternator and / or starter of the system; and / or (d) driving a refrigeration compressor of an air conditioner; and or (e) coupling the mechanical energy generated by the expansion device in a drive train of an internal combustion engine as a heat source, in particular directly to a drive shaft. This will provide further synergies in the system.

According to another embodiment, a partial flow of the vaporized working medium can be used by means of a further expansion machine for driving a fan of the condenser and / or a fan of the radiator. This minimizes conversion losses.

Another development consists in that heat from condensed working medium and / or from the heat source cooling fluid circuit can be decoupled for feeding into a further heat sink. Thus, heat can be coupled out, for example, in heating networks, particularly advantageous are low-temperature heat sinks, such as dryers, floor or surface heating or air heaters.

The object underlying the invention is further achieved by an inventive method according to claim 13.

The method according to the invention is suitable for removing waste heat from a heat source with a cooling device, wherein the cooling device comprises a cooler, a thermodynamic cycle device, in particular an ORC device with a working medium, an evaporator, an expansion device and a condenser and a condenser cooling fluid circuit, and wherein the method comprises the steps of: transferring heat to an ambient medium with the radiator, wherein in particular the radiator is an air cooler and the surrounding medium is air; Vaporizing the working medium with the evaporator by transferring waste heat from the heat source to the working medium; Generating mechanical energy with the expansion device; Condensing the working medium expanded in the expansion device with the condenser; and removing heat from the condenser of the thermodynamic cycle apparatus via the radiator.

The advantages of the method and its developments correspond - unless otherwise stated - those of the device according to the invention.

In the method according to the invention, the following further steps are carried out: passing a first branch of a heat source cooling fluid circuit through the evaporator for transferring heat to the working medium; and first branching a cooling fluid in the heat source cooling fluid circuit upstream of the evaporator into a second branch of the heat source cooling fluid circuit for bypassing the evaporator and merging the second branch with the first branch after the evaporator.

Another development is that the following further steps are performed: second branching of the cooling fluid upstream of the evaporator into a third branch of the heat source cooling fluid circuit, the third branch leading cooling fluid through the radiator and back into the first branch; and / or third branching the cooling fluid downstream of the evaporator into a fourth branch of the heat source cooling fluid circuit, the fourth branch carrying cooling fluid through the radiator and back into the first branch; the cooler comprising an input header, an output header, and intermediate channels each having interconnecting opposite portions of the input header and the output header, and wherein an input of the condenser cooling fluid circuit into the input header and an input of the third and fourth branch of the heat source cooling fluid circuit are spaced from each other in the input header, in particular at respective end portions an input of the condenser cooling fluid circuit are spaced from the output collector and an output of the third and fourth branch of the heat source cooling fluid circuit from the output collector, in particular at respective end portions of the output collector, wherein the input and output the condenser cooling fluid circuit and the heat source cooling fluid circuit are arranged on respectively opposite regions of the input collector and the output collector.

The invention further provides a cooling device and a corresponding method for operating the cooling device.

The cooling device according to the invention comprises: a first cooling fluid circuit, a second cooling fluid circuit and a cooler having an input collector, an output collector, and intermediate channels connecting respective opposite regions of the input collector and the output collector, wherein an input of the first cooling fluid circuit into the input collector and an input of the second cooling fluid circuit is spaced from the input manifold, in particular at respective end portions of the input manifold, and wherein an output of the first cooling fluid circuit from the output manifold and an output of the second cooling fluid circuit are spaced from the output manifold, particularly at respective end portions of the output manifold are arranged, wherein the input and output of the first cooling fluid circuit and the second cooling fluid circuit at respective opposite portions of the Eingangsa mmlers or the output collector are arranged. Preferably, a controllable valve is provided in the first cooling fluid circuit and / or a controllable valve in the second cooling fluid circuit. The radiator may preferentially receive heat from the first and second cooling fluid circuits Transfer cooling medium, wherein the cooling medium may include, for example, water or air.

The method according to the invention for operating the cooling device according to the invention comprises performing the following steps: guiding a first cooling fluid in the first cooling fluid circuit into the inlet of the first cooling fluid circuit into the inlet header of the cooler; Passing a second cooling fluid in the second cooling fluid circuit into the inlet of the second cooling fluid circuit into the inlet header of the radiator; Guiding the first cooling fluid out of the exit of the first cooling fluid circuit from the radiator; and directing the second cooling fluid out of the exit of the first cooling fluid circuit from the radiator. In particular, the first and second cooling fluids have the same composition.

In this way, a division of the existing radiator surface into a high-temperature region (cooling fluid of the first cooling fluid circuit) and a low-temperature region (cooling fluid of the second cooling fluid circuit) is made possible. The distribution of the mass flows in partial mass flows to the terminals of the input collector (ie the respective inputs of the first and second cooling fluid circuit) and thus the distribution of (partial) mass flows through the radiator surface is preferably carried out via one or more valves in the first and / or second cooling fluid circuit. The adaptation of the proportions of the hot or cold radiator surface takes place independently as a function of the partial mass flows.

The cited developments can be used individually or combined as claimed suitable.

Further features and exemplary embodiments and advantages of the present invention will be explained in more detail with reference to the drawings. It is understood that the embodiments do not exhaust the scope of the present invention. It is further understood that some or all of the features described below may be combined with each other in other ways.

drawings

Fig. 1

shows a first embodiment of the system according to the invention.

Fig. 2

shows a second embodiment of the system according to the invention.

Fig. 3

shows a modified version of the second embodiment of the system according to the invention.

Fig. 4

shows a third embodiment of the system according to the invention.

Fig. 5

shows a fourth embodiment of the system according to the invention.

Fig. 6

shows a fifth embodiment of the system according to the invention.

Fig. 7

shows a sixth embodiment of the system according to the invention.

Fig. 8

shows a seventh embodiment of the system according to the invention.

Fig. 9

shows an eighth embodiment of the system according to the invention.

Fig. 10

illustrates the variability of the cooler surfaces.

Fig. 11

is an exemplary illustration of the cooling of mixed cooling water in a T-Q diagram.

Fig. 12

is an exemplary representation of the cooling of separate cooling water in a T-Q diagram.

Fig. 13

illustrates various other synergies in the system of the invention.

embodiments

One way to exploit synergies with existing components of, for example, internal combustion engines as a heat source in the use of heat from a heat source by means of a thermodynamic cycle device - such as an ORC system - is the shared use of an existing cooler for heat removal from the ORC capacitor. Thus, in operating conditions with moderate load, such as moderate outside temperatures, all the heat can be passed through the ORC system and be delivered in the cooler to the environment. Moderate load operation has the largest amount of time in most cooling systems.

The ORC system is designed to receive all the heat from the heat source during nominal operation (outside temperature equal to the nominal temperature). Conversely, this means that it can not absorb all the heat in the maximum load points (high outside temperatures). Since the heat extracted from the ORC is of lower temperature than the cooling fluid, the heat dissipation deteriorates due to the decreasing temperature difference from the environment ΔT _log : $$\dot{Q}=\mathit{UA}\cdot \Delta T_{\mathit{log}}$$

wobei die Temperaturdifferenzen der Medien (Kühlfluid und Luft) vor dem Wärmeaustausch (ΔT₁) und nach dem Wärmeaustausch (ΔT₂) gebildet werden.The logarithmic temperature difference is defined as $$\mathrm{\Delta }{T}_{\mathit{log}}=\frac{\mathrm{\Delta }{T}_1-\mathrm{\Delta }{T}_2}{\ln \left(\mathrm{\Delta }{T}_1/\mathrm{\Delta }{T}_2\right)}$$

wherein the temperature differences of the media (cooling fluid and air) before the heat exchange (.DELTA.T ₁ ) and after the heat exchange (.DELTA.T ₂ ) are formed.

If the logarithmic temperature difference decreases, the required area increases with the same amount of heat, which, however, usually can not be implemented for reasons of space. The problem is exacerbated when other heat sources are involved, e.g. the heat of an ORC system, which uses exhaust heat, for example. Another problem is when heating is to be added as part of a retrofit. Then the radiator geometry is already given. Another problem is when due to cost, the size of a heat exchanger should be kept as compact as possible.

For a simple and fast implementation of the integration of an ORC, for example in a vehicle, it is necessary to minimize the design intervention and limit the influence on the engine while ensuring a high efficiency of the ORC process.

Regarding the advantages of the waste heat utilization from the cooling water of the internal combustion engine with an ORC device and using the energy obtained with the ORC system in the drive device, the large efficiency increase of the engine in the range of several percent, cost savings and space savings through fewer components compared to ORC -Systems that use exhaust heat to call. A disadvantage is first in the first embodiment of the invention that the cooler at maximum load of the engine, the heat dissipation of the ORCs generally can not ensure, but this is remedied or at least mitigated in the other embodiments.

In the embodiments described below, only water is used as cooling fluid (cooling water) by way of example. Furthermore, the cooler is provided by way of example only as an air cooler, so that waste heat is transferred to air. According to the invention, however, another medium (such as water) can absorb the heat dissipated in the radiator.

Fig. 1 shows a first embodiment of the system according to the invention in the form of a drive system.

The drive system 100 according to the invention comprises in this embodiment an internal combustion engine 10 and a cooling device for removing waste heat from the internal combustion engine, the cooling device comprising: an air cooler 20 for transferring heat to air; and an ORC device 30 with a working medium, an evaporator 31 for evaporating the working medium by transferring waste heat of the internal combustion engine 10 to the working medium, an expansion device 32 for generating mechanical energy (which is converted here by way of example via a generator G into electrical energy) and a condenser 33 for condensing the working medium expanded in the expansion device 32; wherein the cooling device further comprises a condenser cooling fluid circuit 40 for removing heat from the condenser 33 of the thermodynamic cycle apparatus via the radiator 20. The cooling device further includes an engine cooling fluid circuit 50, wherein a first branch 51 of the engine cooling fluid circuit 50 is through the Evaporator 31 leads to the transfer of heat to the working medium. The engine cooling fluid circuit comprises, in the flow direction of the cooling water before the evaporator, a first branch 81 into a second branch 52 of the engine cooling fluid circuit 50 for bypassing the evaporator 31 and a merging 91 of the second branch 52 with the first branch 51 downstream of the evaporator 31, wherein the second branch 52 comprises a controlled valve 71, for example with a thermostat.

This is a basic interconnection, and it allows the use of energy from the engine cooling water. In one example, the outlet temperature of the engine cooling water (MKW) via the controlled valve (in particular thermostatic valve) 71 is driven to about 110 ° C. By default, the MKW outlet temperature is lower, in the range of 80 ° C. The increase results in a higher performance of the ORC process. In an alternative embodiment, instead of the generator G, the coupling of the energy can also be done directly (mechanically or hydraulically), as with all subsequent interconnections.

The following problem arises during operation: The system 100 has no run-flat capability in the event of ORC failure or insufficient heat dissipation. When the ORC process 30 is at the limit of its heat absorption or is not operating, the water circuit 50 heats up and the engine 10 overheats or is downshifted by an engine control.

Fig. 2 shows a second embodiment of the drive system according to the invention. Like reference numerals designate the same components as in FIG Fig. 1 , In the following, only the additional components will be described.

In contrast to the first embodiment, in the second embodiment of the drive system 200, a coupling of heat from the exhaust gas of the engine 10 via an exhaust gas heat exchanger 15 into the engine cooling fluid circuit 50 is still provided. The engine cooling fluid circuit 50 includes, in the flow direction of the cooling fluid upstream of the evaporator 31, a second branch 82 into a third branch 53 of the engine cooling fluid circuit 50, the third branch 53 being adapted to provide cooling fluid through the radiator 20 and back into the radiator first branch 51, wherein the second branch 82 comprises a second valve 72, for example a three-way valve 72. If the heat transfer capacity of the radiator 20 is insufficient, water can be passed directly to the radiator 20 via the second valve 72. The engine cooling fluid circuit 50 has, in the flow direction of the cooling fluid downstream of the evaporator 31, a third branch 83 into a fourth branch 54 of the engine cooling fluid circuit 50, the fourth branch 54 leading cooling water through the radiator 20 and back into the first branch 51 the third branch 83 has a third valve 73, in particular a three-way valve 73, wherein a junction 94 of the fourth branch 54 is provided in the third branch 53. The engine cooling fluid circuit 50 comprises in the flow direction of the cooling fluid in front of the radiator 20 a merging 95 of the third and fourth branches 53, 54 with the condenser cooling fluid circuit 40.

An emergency running capability is provided via the 3-way valves 72 and 73, respectively. In operation of the ORC, the average temperature at the entrance of the radiator 20 decreases (due to the merging 95 of the engine cooling fluid circuit 50 and the condenser cooling fluid circuit 40), which adversely affects the heat transfer capacity resulting from the logarithmic temperature difference between the heat absorber and the heat dissipator Medium is determined. If the heat transfer capacity of the radiator 20 is insufficient and / or if there is no or insufficient cooling of the engine cooling water in the evaporator 31, then Motokühlwasser is passed directly to the radiator 20 via one of the two valves 72 or 73 or by the actuation of both valves. As a result, the temperature of the water supplied to the radiator 20 increases, the logarithmic temperature difference increases, and more heat is transmitted. The disadvantage, however, is that the ORC is also flowed through with relatively hot water, which has a negative effect on the electrical power.

Fig. 3 shows one opposite Fig. 2 modified embodiment 210 of the system according to the invention. Instead of the second valve 72 is here a pump P4 and instead of the third valve 73, a pump P5 is provided. Both pumps serve to control the mass flow to the radiator 20 and are thus controllable pumps.

Furthermore, the pump P3 can be made adjustable. This can be regulated depending on the pump P4, the pump P5 or the corresponding 3-way valve. The aim of this measure is to improve the heat dissipation of the heat exchanger 20 and / or to minimize the auxiliary energy expenditure for the pumps.

If after wiring in Fig. 3 the flow rate of the pump P3 is reduced, then the inlet temperature increases in the WÜ20 and thus the temperature difference to the cooling medium (eg ambient air). This allows more heat to be transferred.

If after wiring in Fig. 3 Increased fluid is passed through line 53 for cooling, a lot of heat transfer surface for the high-temperature component is needed. In this case, the pump P3 can be downshifted, thus the total volume flow over the heat exchanger surface is reduced and as a result the pressure difference that must be applied by the pumps P3 to P5 is reduced. Conversely, therefore, there is much area available for the ORC capacitor when flowing through line 53 little fluid. This is the case, for example, when all or most of the heat can be dissipated through the ORC.

This ensures a critical function of the process (ensuring area for high-temperature cooling) and achieves faster and more efficient control. The control can be realized, for example, by maps or parametric tables are stored in the plant control that control the speed of the pump P3.

In the extreme case that the high-temperature heat dissipation is to be maximized, the ORC process including the pump P3 is switched off. In order to prevent a partial flow from bypassing the cooler 20, a backstop can be provided in front of the pump P3.

Fig. 4 shows a third embodiment of the drive system according to the invention. Like reference numerals designate the same components as in FIG Fig. 1 and 2 , In the following, only the additional components will be described.

According to the third embodiment of the drive system 300 according to the invention, the cooler 20 has an input header 21, an output header 25, and has intermediate channels connecting respective opposite portions of the input header 21 and the output header 25, one input 22 of the condenser cooling fluid circuit 40 are arranged in the input header 21 and an inlet 23 of the third branch 53 of the engine cooling fluid circuit 50 in the input header 21 at respective end portions of the input header 21, and wherein an output 26 of the condenser cooling fluid circuit 40 from the output header 25 and an output 27 of third branch 53 of the engine cooling fluid circuit 50 from the output manifold 25 are disposed at respective end portions of the output manifold 25, wherein the input 22, 23 and output 26, 27 of the condenser cooling fluid circuit 40 and the engine cooling fluid circuit 50 at respectively s opposite areas of the input collector 21 and the output collector 25 are arranged.

Thus, a division of the existing radiator surface in a high temperature range (engine cooling water, MKW) and a low temperature range (return to the ORC capacitor). Depending on the operating point, a portion of the MKW mass flow may be passed through the ORC 30 and a portion cooled directly against air, as described for the second embodiment. This makes it possible to separate the two mass flows, and then the ORC condenser as low as possible temperature can be made available in this way and the removal of excess heat can be done at a high temperature level, which is beneficial to the performance of a radiator and also has a positive effect on the auxiliary energy requirement for dissipating the heat to the environment.

The third embodiment provides a solution to realize the simplest possible way a division of the two partial streams on the surface of the radiator and adjust this distribution depending on the operating state advantageous. The The requirements here are that most of the heat is conducted through the ORC in order to maximize the efficiency of the overall system. Furthermore, it is particularly advantageous to use the lowest temperature for cooling the capacitor in order to ensure a higher efficiency of the ORC process. In addition, suitable return temperatures for the engine must be maintained. Although this would be realized by structurally or hydraulically separate cooler, but then available for the respective mass flows areas are fixed, but this does not fit to different load points.

The distribution of the mass flow in the branch 82 and 83 takes place by means of the valve 72 or 73. This passes depending on the temperature or another characteristic value a partial flow of the MKW to the radiator 20. The temperature limit depends on whether the variant with valve 72 or 73 is present. For example, upon reaching a maximum cooling water temperature, valve 72 would switch the flow toward radiator 20 and bypass the ORC. The valve 73 directs the cooling water in the direction of the radiator 20 when a required cooling is not achieved.

Fig. 5 shows a fourth embodiment of the drive system according to the invention. Like reference numerals designate the same components as in FIG Fig. 1 to 3 , In the following, only the additional components will be described.

According to the fourth embodiment 400 of the drive system according to the invention, a further branch is provided in front of the radiator 20 in relation to the third embodiment 300 to pass hot cooling fluid over a heat sink 110 to otherwise utilize a portion of the heat, for example for heating purposes.

In the fifth and sixth embodiments according to Fig. 6 and 7 is the interconnection according to the invention, extended by the inclusion of a further cooling circuit at a further temperature level (eg cooling circuit for the intercooler, LLK) with a heat exchanger W (heat dissipation of the charge air cooling circuit), the analogous to the radiator 20, a fluid (eg charge air cooling medium) cools , The heat exchanger W can be connected in series with the heat exchanger 20 on the air side ( Fig. 6 ), and the cooling air or other cooling medium can first passed through the heat exchanger W and then through the heat exchanger 20. Likewise, a parallel flow is possible ( Fig. 7 ).

The ORC circuit is not shown here for simplicity, a connection with the ORC circuit is only hinted at in this variant.

In the sixth embodiment according to Fig. 7 it is possible to connect in series the ORC condenser and the radiator 20 on the water side. The cooler 20 then cools the entire mass flow. When the engine is still warming up, no mass flow will flow towards the evaporator. At partial load, little mass flow flows in the direction of the evaporator, and there is then an oversized cooler available. This can provide the ORC capacitor with a low temperature.

Although this results in a lower maximum available flow through the ORC capacitor, but this can be overcompensated by the lower inlet temperature, so outweigh the benefits.

Another advantage is that only one pump is needed to flow through the condenser and the radiator 20.

In some operating states, not the entire surface of the heat exchanger W is now required for cooling the further cooling circuit. Then you can use the area reserve of the heat exchanger W for the cooling of the ORC circuit. This is demonstrated by the interconnection shown below in the seventh embodiment Fig. 8 allows. The control can be done here, for example, depending on the outlet temperature T of heat exchanger W. In the event that for the ORC cooling additional area of heat exchanger W needed AND in the heat exchanger W to this operating state, an area reserve is present, opens a valve V (eg, as shown, a 3-way valve) or another Device that allows such a liquid allocation, such as a pump. As a result, a partial flow of the cold further cooling circuit is passed in the direction of the ORC capacitor. After passing through the condenser, the partial flow is fed in again upstream of the heat exchanger W in order not to negatively influence the temperature of the further cooling circuit.

Analogously, further circuits with further temperatures can also be integrated (for example, the cooling circuit for the air conditioning in the vehicle).

Also the interconnection after Fig. 6 can be like in the Fig. 9 evolve illustrated eighth embodiment, so that the capacity of the other cooling circuit can be used for the ORC cooling.

The operation of the distribution of the mass flows in the third and fourth embodiments will be described below in connection with Fig. 10 described. Adjusting the proportions of the hot or cold radiator surface takes place automatically in this interconnection depending on the mass flows, which are passed through the 3-way valve 72 and 73 to the radiator. The greater the mass flow ṁ _{H of} the hot MKW or ṁ _{K of} the cold condenser circuit, the greater the respective proportion of the cooler surface. The underlying operating principle is that an equal pressure difference is established between flow and return. If, at a first connection, a first mass flow or volume flow into the cooler is increased, this would result in the first step in a larger pressure loss in the channels of the cooler through which the first volume flow flows. However, since the channels are connected via the collector, the same pressure loss prevails over all channels, so that the volume flow increases through the channels through which the second mass flow flows. However, if the second mass flow remains constant, then the number of channels must be reduced, so that more area is available for the larger first mass flow and the pressure losses are correspondingly adjusted.

Due to the separation of temperature levels, the available heat exchanger surface of the cooler 20 is advantageously used in the best possible way. Compared to the (previously described) mixing of the temperatures of two partial streams significantly lower temperatures can be achieved on the cold side. This has advantages in the operation of an ORC but also for all other applications where two temperature levels are to be recooled via a circuit, as is the case, for example, with stationary engines for cooling the engine cooling water and the charge air. The proposed interconnection can heat at the highest possible Temperature difference are dissipated to the environment, resulting in a reduction of the auxiliary energy demand, and the lower-temperature flow rate is cooled to lower temperatures than when mixing the two volume flows. The device can be provided as shown in a cooler but also by the connection of any number of coolers by means of pipelines.

The FIGS. 11 and 12 explain the operation and advantages of the interconnection according to the third and fourth embodiments in comparison with the second embodiment in TQ diagrams (T: temperature, Q: heat flow).

Fig. 11 shows an example of the cooling of the water mass flow of 90 ° C, the hotter of the two heat sources allows a temperature of 115 ° C. It is achieved a recooling temperature of the water of 70 ° C.

When using two temperature levels, as in Fig. 12 As illustrated, the first 115 ° C mass flow enters the radiator and is cooled down to 88 ° C in this example, which temperature is set when 20% of the total mass flow passing through the radiator is at a high temperature level. As described above, the areas split according to the mass flow, and thus are available for the heat transfer of the first, hot mass flow 20% of the area available. Calculating the heat flows, however, 27% of the total amount of heat is transferred over this area. The remaining 73% of the heat is then transferred over the remaining 80% of the surface, which is now possible at lower temperatures. Thus, this amount of heat can be transmitted with a flow temperature of hot water of 84 ° C and a return temperature of 65 ° C, which means a lower by 5 K return temperature. This is accompanied by performance enhancement of the ORC or improvement of heat transfer in other components (charge air cooler etc.).

It is noted here that the described temperature and power values can only be seen by way of example; by optimizing and adapting temperature limits, even further potential can be raised. An optimization takes into account the temperature as well as the influence of the mass flow on the heat transfer capacity / performance of a heat exchanger.

The propulsion system can be further developed with regard to further synergies associated with Fig. 13 and each of which can be used individually or in combination. The mechanical energy generated by the expansion device may be usable via a respective electrical, mechanical or hydraulic coupling for (a) driving a fan of the condenser 30 and / or a fan of the radiator; and / or (b) driving a circulation pump 101 in the engine cooling fluid circuit and / or a feed pump 102 of the thermodynamic cycle device and / or a circulation pump 103 in the condenser cooling fluid circuit and / or a water pump and / or a hydraulic pump and / or an oil pump; and / or (c) driving an alternator 105 and / or a starter of the drive system; and / or (d) driving a refrigeration compressor 106 of an air conditioner. A partial flow of the vaporized working medium may be used to drive a fan of the condenser and / or a fan 107 of the radiator. This minimizes conversion losses. Furthermore, heat may be extracted from condensed working fluid and / or from the engine cooling fluid circuit for delivery to a heater.

The illustrated embodiments are merely exemplary and the full scope of the present invention is defined by the claims.

Claims (14)

1. System for heat utilization, comprising:

   a heat source (10); and

   a cooling device for discharging heat from the heat source;

   wherein the cooling device comprises:

   a heat exchanger / radiator (20) for transferring heat to a surrounding medium, wherein in particular the radiator is an air cooler and the surrounding medium is air; and

   a thermodynamic cycle device (30), in particular an ORC device, having a working medium, an evaporator (31) for evaporating the working medium by transferring heat of the heat source (10) to the working medium, an expansion device (32) for generating mechanical energy, and a condenser (33) for condensing the working medium expanded in the expansion device (32);

   wherein the cooling device comprises a condenser coolant circuit (40) for discharging heat from the condenser (33) of the thermodynamic cycle device (30) via the heat exchanger / radiator (20); and

   wherein the cooling device further comprises a heat source coolant circuit (50), wherein a first branch (51) of the heat source coolant circuit passes through the evaporator (31) for transferring heat to the working fluid;

   characterized in that

   the heat source coolant circuit in the flow direction of a cooling fluid upstream of the evaporator comprises a first branch-off (81) into a second branch (52) of the heat source coolant circuit (50) for bypassing the evaporator (31) and a merging (91) of the second branch (52) with the first branch (51) downstream of the evaporator (31), the second branch (52) comprising a first valve (71), preferably a controlled valve.
2. System according to claim 1, wherein the heat source comprises a power process device, in particular an internal combustion engine (10), a gas turbine or a Stirling engine, a boiler, in particular a biomass burner, or a fuel cell.
3. System according to claim 1 or 2, wherein in the heat source coolant circuit, a first pump (P1) and / or in the thermodynamic cycle device, a second pump (P2) for pumping the working medium and / or in the condenser coolant circuit, a third pump (P3) is provided.
4. System according to any one of claims 1 to 3, wherein the heat source coolant circuit in the flow direction of the cooling fluid upstream of the evaporator comprises a second branch-off (82) into a third branch (53) of the heat source coolant circuit, and wherein the third branch is configured to move cooling fluid through the heat exchanger / radiator and back into the first branch, wherein the second branch-off preferably comprises a second valve (72), in particular a three-way valve, or wherein the third branch preferably comprises a fourth pump (P4).
5. System according to any one of claims 1 to 4, wherein the heat source coolant circuit comprises, in the flow direction of the cooling fluid downstream of the evaporator, a third branch-off (83) into a fourth branch (54) of the heat source coolant circuit, and wherein the fourth branch is configured to move cooling fluid through the heat exchanger / radiator and back into the first branch, wherein the third branch preferably comprises a third valve (73), in particular a three-way valve, or wherein the fourth branch preferably comprises a fifth pump (P5), wherein in combination with claim 4, a merging of the fourth branch into the third branch is provided.
6. System of claim 4 or 5, wherein the heat source coolant circuit in the flow direction of the cooling fluid upstream the heat exchanger / radiator comprises a merging (95) of the third and/or fourth branch with the condenser coolant circuit.
7. System of claim 4 or 5, wherein the heat exchanger / radiator has an inlet collector (21), an outlet collector 25), and intermediate channels interconnecting respective opposite portions of the inlet collector and the outlet collector, and wherein an inlet (22) of the condenser cooling fluid cycle into the inlet collector and an inlet (23) of the third and/or fourth branch of the heat source coolant circuit into the inlet collector are spaced from each other, in particular at respective end portions of the inlet collector, and wherein an outlet (26) of the condenser coolant circuit from the outlet collector and an outlet (27) of the third and/or fourth branch of the heat source coolant circuit from the outlet collector are spaced from each other, in particular arranged at respective end portions of the outlet collector, wherein the inlet (22, 23) and outlet (26, 27) of the condenser coolant circuit and the heat source coolant circuit are each arranged at respective opposite areas of the inlet collector and the outlet collector.
8. System according to any one of claims 1 to 7, wherein the cooling device further comprises at least one heat exchanger (15) for transferring heat in exhaust gas of the heat source to the heat source coolant circuit.
9. System according to any one of claims 1 to 8, further comprising a generator (G), by means of which the mechanical energy generated by the expansion device is convertible into electrical energy.
10. System according to any one of claims 1 to 9, wherein by the energy generated by the expansion device (32) mechanical energy can be used via a respective electrical, mechanical or hydraulic coupling for

    (a) driving a fan of the condenser (30) and / or a fan of the heat exchanger / radiator; and / or

    (b) driving a circulation pump (101) in the heat source coolant circuit and / or a feed pump (102) of the thermodynamic cycle device and / or a circulation pump (103) in the condenser coolant circuit and / or a water pump and / or a hydraulic pump and / or an oil pump; and or

    (c) driving a generator (105) and / or a starter of the drive system; and / or

    (d) driving a refrigeration compressor (106) of an air conditioner; and / or

    (e) coupling the mechanical energy generated by the expansion device in a drive train of the heat source, in particular directly to a drive shaft, wherein the heat source comprises a power process device, in particular an internal combustion engine.
11. System according to any one of claims 1 to 10, wherein a partial flow of the vaporized working medium is usable to drive a fan of the condenser and / or a fan (107) of the heat exchanger / radiator and / or a refrigeration compressor; and / or
    wherein heat from condensed working medium and / or from the heat source coolant circuit for feeding into a heating device can be coupled out.
12. System according to any one of claims 1 to 11, further comprising: a further cooling circuit with a further heat exchanger, wherein the further heat exchanger is connected in series with or parallel to the heat exchanger / radiator.
13. Method for discharging heat from a heat source by means of a cooling device,
    wherein the cooling device comprises a heat exchanger / radiator, a thermodynamic cycle device, in particular an ORC device, with a working medium, an evaporator, an expansion device and a condenser and a condenser coolant circuit, and wherein the method comprises the following steps:

    transferring heat to an surrounding medium with the heat exchanger / radiator, wherein in particular the radiator is an air cooler and the surrounding medium is air;

    vaporizing the working medium with the evaporator by transferring heat from the heat source to the working medium;

    generating mechanical energy by means of the expansion device;

    condensing the working medium expanded in the expansion device by means of the condenser;

    discharging heat from the condenser of the thermodynamic cycle device via the heat exchanger / radiator; and

    passing a first branch of a heat source coolant circuit through the evaporator to transfer heat to the working fluid;

    characterized by

    first branching-off of a cooling fluid in the heat source coolant circuit in the flow direction upstream the evaporator into a second branch of the heat source coolant circuit for bypassing the evaporator and merging the second branch with the first branch downstream the evaporator.
14. Method of claim 13, further comprising the steps of:

    second branching-off of the cooling fluid upstream of the evaporator into a third branch of the heat source coolant circuit, the third branch passing cooling fluid through the heat exchanger / radiator and back into the first branch; and or

    third branching-off of the cooling fluid downstream of the evaporator into a fourth branch of the heat source coolant circuit, the fourth branch passing cooling fluid through the heat exchanger / radiator and back into the first branch;

    wherein the heat exchanger / radiator has an inlet collector, an outlet collector, and intermediate channels interconnecting respective opposite portions of the inlet collector and the outlet collector, and wherein an inlet of the condenser cooling fluid cycle into the inlet collector and an inlet of the third and/or fourth branches of the heat source coolant circuit into the inlet collector are spaced from each other, in particular at respective end portions of the inlet collector, and wherein an outlet of the condenser coolant circuit from the outlet collector and an outlet of the third and/or fourth branch of the heat source coolant circuit from the outlet collector, respectively, are spaced from each other, in particular arranged at respective end portions of the outlet collector, wherein the inlet and outlet of the condenser coolant circuit and of the heat source coolant circuit are arranged at respective opposite portions of the inlet and the outlet collector.

Images