Device for supplying thermal energy to a heat sink

Abstract

Device (2) for supplying thermal energy to a heat sink, with an internal combustion engine (4) and with an electric motor (6), wherein the internal combustion engine (4) and the electric machine (6) are interconnected in a first operating mode in the manner of a combined heat and power plant, wherein the internal combustion engine (4) acts as a motor and the electric machine (6) as a generator, characterized by that the device (2) is switchable from the first operating mode to a second operating mode in which the electric machine (6) acts as a motor and drive for the internal combustion engine (4) and the internal combustion engine (4) acts as a compressor, such that a refrigerant is heated by compression in a working chamber of the internal combustion engine (4), that the working chamber of the internal combustion engine (4) is in flow communication with at least one first heat exchanger (10) for the transfer of thermal energy of the refrigerant to a heat sink and that, in the direction of flow of the refrigerant, an expansion valve (14) and at least a second heat exchanger (16) are arranged downstream of the first heat exchanger (10) for heating the refrigerant, wherein an outlet of the second heat exchanger (16) is in flow communication with the working chamber of the internal combustion engine (4) for introducing the refrigerant heated in the second heat exchanger (16) into the working chamber of the internal combustion engine (4).

Description

[0001] The invention relates to a device of the type mentioned in the preamble of claim 1 for providing thermal energy to a heat sink.

[0002] Such devices are well known and consist of an internal combustion engine and an electric motor, which are interconnected in a combined heat and power (CHP) plant, with the internal combustion engine acting as the motor and the electric motor as the generator. These CHP plants generate electricity via the electric motor, while heat from the exhaust gas of the internal combustion engine is used to heat water in a heating system.

[0003] DE 10 2009 028 235 A1 describes a method and a device for utilizing waste heat from an internal combustion engine of vehicles with an air conditioning circuit that includes a compression machine.

[0004] DE 10 2019 130 215 A1 describes a device for generating electrical energy from waste heat and for conditioning supply air, in particular a passenger compartment of a motor vehicle.

[0005] The invention is based on the objective of providing an improved device of the type mentioned in the preamble of claim 1 for supplying thermal energy to a heat sink, compared to known devices.

[0006] This problem is solved by the invention specified in claim 1.

[0007] Advantageous and appropriate further developments of the invention are specified in the dependent claims.

[0008] The invention provides that the device can be switched from the first operating mode to a second operating mode in which the electric motor acts as the motor and drive for the internal combustion engine, and the internal combustion engine acts as the compressor, such that a refrigerant is heated by compression in a working chamber of the internal combustion engine. According to the invention, the working chamber of the internal combustion engine is in flow communication with at least one first heat exchanger for transferring thermal energy from the refrigerant to a heat sink. Downstream of the first heat exchanger, an expansion valve and at least one second heat exchanger for heating the refrigerant are arranged, with an outlet of the second heat exchanger being in flow communication with the working chamber of the internal combustion engine for introducing the refrigerant heated in the second heat exchanger into the working chamber of the internal combustion engine.

[0009] The invention is based on the understanding that the components of a combined heat and power plant (CHP), namely an electric motor and an internal combustion engine, can be used as components of a heat pump by reversing their operating principle. While in a CHP plant the electric motor is used as a generator to produce electricity, in a heat pump the electric motor serves to drive a compressor. Building on this, the invention is based on the further understanding that the internal combustion engine used in a CHP plant can also be used as a compressor, by reversing its operating principle, which in a heat pump is used to compress and heat a refrigerant.

[0010] The invention is based on the idea of ​​operating the internal combustion engine as a compressor in a second operating mode, and then successively arranging a first heat exchanger, an expansion valve, and a second heat exchanger downstream of it in the direction of refrigerant flow. The internal combustion engine is thus used to compress the refrigerant, causing it to be highly compressed and heated. The compressed refrigerant is then passed through the first heat exchanger, releasing some of its heat as usable heat, for example, to a heating system.

[0011] The cooled refrigerant is passed through the expansion valve (decompression valve), which reduces its pressure and temperature. The cooled refrigerant is then able to absorb ambient heat via the second heat exchanger, as is the operating principle of a heat pump.

[0012] The refrigerant, heated by the ambient heat, is then fed back to the internal combustion engine.

[0013] The invention thus provides a device that can be used as a combined heat and power plant in its first operating mode, while it can be used as a heat pump in its second operating mode.

[0014] In the first operating mode (combined heat and power plant mode), the internal combustion engine is operated as a motor, whose waste heat can be used to provide thermal energy to a heat sink, for example a heating system, while the electric machine, operated as a generator, generates electricity.

[0015] In contrast, in the second operating mode (heat pump mode), the electric machine is used as a motor to drive the internal combustion engine used as a compressor.

[0016] The invention thus provides a hybrid solution between a combined heat and power plant and a heat pump, which can be operated according to the respective conditions and requirements.

[0017] The invention is explained in more detail below with reference to the accompanying block diagram-like drawing and an exemplary embodiment. It is evident to those skilled in the art that the individual features of an exemplary embodiment, considered separately, further develop the exemplary embodiment, so that it is clear to those skilled in the art that all the features described, illustrated in the drawing, and claimed in the patent claims, considered separately and in any technically meaningful combination with one another, constitute the subject matter of the invention, irrespective of their compilation in the patent claims and their cross-references, and irrespective of their specific description or representation in the drawing.The subject matter and disclosure content of the present application also include sub-combinations of the patent claims in which at least one feature of a patent claim is omitted or replaced by another feature.

[0018] It shows: Fig. 1 block diagram-like embodiment of a device according to the invention in a first operating mode and Fig. 2 in the same representation as Fig. 1 the embodiment according to Fig. 1 in a second operating mode.

[0019] In Fig. Figure 1 illustrates, in block diagram form, the operation of an embodiment of a device 2 according to the invention for providing thermal energy to a heat sink in a first operating mode (combined heat and power plant mode). The device 2 comprises an internal combustion engine 4, which in the illustrated embodiment is designed as a reciprocating engine. The internal combustion engine 4 is operatively connected to an electric motor 6. When the device 2 is operating, the internal combustion engine 4 is operated as a motor and supplied with fuel. The internal combustion engine 4, as a motor, drives the electric motor 6, which operates as a generator and produces electricity. During operation, heat emitted by the internal combustion engine 4 is fed to an exhaust gas heat exchanger 8 and transferred from there to a heat sink, for example, a heating system.

[0020] Fig. Figure 2 illustrates the functionality of the device 2 according to the invention in a second operating mode in block diagram form.

[0021] According to the invention, the device 2 can be switched from the first operating mode to the second operating mode (heat pump mode), in which the electric machine 6 is used as a motor and drive for the internal combustion engine 4 and the internal combustion engine acts as a compressor, such that a refrigerant, which in the illustrated embodiment is formed by air, is heated by compression in a working chamber of the internal combustion engine 4.

[0022] The working chamber of the internal combustion engine 4 is in flow communication with at least one first heat exchanger 10 for transferring thermal energy of the refrigerant to a heat sink, for example a heating system.

[0023] In the direction of refrigerant flow, which is in Fig.2, symbolized by an arrow 12, an expansion valve 14 and a second heat exchanger 16 are arranged downstream of the first heat exchanger 10 for heating the refrigerant using ambient heat, wherein an outlet of the second heat exchanger 16 is in flow communication with the working chamber of the internal combustion engine for introducing the refrigerant heated in the second heat exchanger 16 into the working chamber of the internal combustion engine 4.

[0024] In heat pump mode, the internal combustion engine 4, driven by the electric motor 6, is used to compress the refrigerant. During compression, the refrigerant is highly compressed and heats up in the process. The compressed refrigerant is passed through the first heat exchanger 10 and releases some of its heat as usable heat, for example, to a heating system. The cooled refrigerant is then passed through the expansion valve 14, where its pressure and temperature decrease. The cooled refrigerant is then able to absorb ambient heat in the second heat exchanger 16. The refrigerant, now heated by the ambient heat, is then introduced into the combustion chamber of the internal combustion engine 4.

[0025] The following applies to the pressure and temperature conditions of the refrigerant in the system: P2>P1 T4 <Umgebungswa¨rme T1 <T2 T3 <T2

[0026] The invention thus provides a device that can be operated both as a combined heat and power plant and as a heat pump, so that by cleverly using the components of a combined heat and power plant a hybrid solution between a combined heat and power plant and a heat pump is provided.

Claims

[1] Device (2) for supplying thermal energy to a heat sink, with an internal combustion engine (4) and with an electric motor (6), wherein the internal combustion engine (4) and the electric machine (6) are interconnected in a first operating mode in the manner of a combined heat and power plant, wherein the internal combustion engine (4) acts as a motor and the electric machine (6) as a generator, characterized by , that the device (2) is switchable from the first operating mode to a second operating mode in which the electric machine (6) acts as a motor and drive for the internal combustion engine (4) and the internal combustion engine (4) acts as a compressor, such that a refrigerant is heated by compression in a working chamber of the internal combustion engine (4), that the working chamber of the internal combustion engine (4) is in flow communication with at least one first heat exchanger (10) for the transfer of thermal energy of the refrigerant to a heat sink and that, in the direction of flow of the refrigerant, an expansion valve (14) and at least a second heat exchanger (16) are arranged downstream of the first heat exchanger (10) for heating the refrigerant, wherein an outlet of the second heat exchanger (16) is in flow communication with the working chamber of the internal combustion engine (4) for introducing the refrigerant heated in the second heat exchanger (16) into the working chamber of the internal combustion engine (4). [2] Device according to claim 1, characterized by , that the internal combustion engine (4) is a reciprocating engine. [3] Device according to claim 1 or 2, characterized by that the refrigerant is air.

Images