DE102017206327A1 - Device for receiving or emitting heat in a heat pump system for a motor vehicle - Google Patents

Abstract

A heat pump system for a vehicle includes a refrigerant circuit (12) each having at least one refrigerant-refrigerant heat exchanger (2, 3) upstream and downstream of a compressor (1) and a refrigerant circuit (28) having at least one heat source, such as a compressor. a radiator (4), a charge air cooler (6), an electric motor (7) and / or electronic components (8) and is characterized in that the coolant circuit (28) selectively connectable with one or both heat exchangers (2, 3) is.

Description

Technical area

The invention relates to a device which serves to absorb heat of vaporization and the release of Enthitzungs- or condensation heat of the refrigerant in a heat pump system of a motor vehicle with a low-temperature coolant circuit. The inventive arrangement of two refrigerant-coolant heat exchangers preferably immediately before or after the refrigerant compressor, the refrigeration cycle can be integrated both in the high-pressure and on the low-pressure side in the low-temperature coolant circuit of the vehicle.

For the comfort of the occupants, a vehicle interior, depending on the ambient temperature, to heat or cool or dehumidify. When cooling the interior heat is removed and discharged in a condenser to the environment. The same applies to heat that is emitted for example in an electric vehicle from a battery to keep it sufficiently cool.

When heating u.a. uses the heat that a refrigerant absorbs when evaporating. Here, a significant source of heat is the environment, which entails certain restrictions.

For example, the performance and COP of a heat pump system are limited at cold ambient temperatures because water vapor can freeze on the surface of an evaporator. This affects the air-side heat transfer and thus the efficiency of the heat pump system as a whole. Therefore, typically at lower ambient temperatures (about 5 ° C), the input pressure at a compressor of the refrigerant circuit must be limited down to regulate or limit the heat of vaporization absorbed by the environment. The resulting reduction in heating power may cause it to become insufficient to sufficiently warm a vehicle interior.

State of the art

This disadvantage applies, for example, for that from the DE 10 2004 001 233 A1 known air conditioning system. With this air conditioning system, no heat of vaporization from the low-temperature coolant circuit can also be absorbed into the refrigerant circuit during heat pump operation, which may possibly be another reason for insufficient heating power. For that from the US 2012/0183815 A1 known air conditioning system has a disadvantage in terms of the release of Enthitzungs- or condensation heat in the coolant circuit in refrigeration system operation.

Presentation of the invention

Against this background, the invention has for its object to provide a heat source for receiving heat of vaporization and a heat sink for delivering Enthitzungs- or condensation heat of the refrigerant in a heat pump system for a vehicle, such as an electric or hybrid vehicle to create that for a particular wide range of ambient temperatures allows efficient cooling and / or heating of the interior.

The solution of this object is achieved by the heat pump system described in claim 1.

Accordingly, the vehicle has a refrigerant circuit for air conditioning the vehicle interior, designed for combined operation in the refrigeration system mode, in the heat pump mode and in the reheating mode, at least two refrigerant-refrigerant heat exchangers, which are preferably arranged immediately upstream and downstream of a refrigerant compressor, and a coolant circuit with a Coolant-air heat exchanger (radiator), which can be used for cooling an electric motor, one or more electronic components and / or a charge air cooling. According to the invention, the coolant circuit can optionally be connected to one or both refrigerant-coolant heat exchangers of the refrigerant circuit.

As a result, both in the refrigeration system operation and in the heat pump operation, a heat transfer between the refrigerant and the refrigerant circuit is made possible both on the low-pressure side and on the high-pressure side of the refrigerant circuit. In other words, the refrigerant circuit is integrated in particular in the low-temperature coolant circuit. As a result, both the heat from the vehicle interior and from an electric motor, electronic components or a charge air cooling via the radiator to the environment in cooling system operation. In heat pump operation, not only the radiator serves as heat source in an advantageous manner, but also the waste heat of an electric motor and / or electronic component or a charge air cooling can be used as an additional heat source for the evaporation of the refrigerant. In particular, this advantageously avoids an additional electrical heater or positive temperature coefficient (PTC). Advantageously, at particularly low ambient temperatures, the radiator can be bypassed, so that in the coolant circuit only the waste heat of the electric motor and / or electronic component or the intercooler serves as a heat source to avoid the problems described above with the icing of the coolant-air heat exchanger (radiator).

Furthermore, according to the invention, an operation is possible in which the coolant of the coolant circuit is divided between the two described refrigerant coolant heat exchangers of the refrigerant circuit. As a result, heat can advantageously be transferred between the low-pressure side and the high-pressure side of the refrigerant circuit, and furthermore the coolant-side connection to other heat sources, such as an electric motor, can exist. At the same time, the disadvantages of freezing water vapor on the radiator can be avoided. It should be emphasized that the refrigerant circuit can incidentally be carried out conventionally, in other words, heat can additionally be taken up on the low-pressure side via one or more heat exchangers and / or heat can be released on the high-pressure side via one or more heat exchangers. The heat pump system may also be operated with any coolant, water or air. This applies equally to all refrigerants for which R 744, R 134a and R 1234yf are mentioned. It should finally be mentioned that the heat pump system advantageously allows cooling of components such as an electric motor and / or electronic components in all modes. At least one, preferably both refrigerant-refrigerant heat exchangers described are preferably located immediately before or after the compressor.

Advantageous developments of the system according to the invention are described in the further claims.

For the avoidance of refrigerant-side pressure losses, it offers advantages if at least one refrigerant-coolant heat exchanger has a closable coolant-side bypass. The bypass is opened when heat transfer in the respective refrigerant-refrigerant heat exchanger is not required, so that, as mentioned, the operation can be carried out without unnecessary pressure loss.

The various modes of operation according to the invention can be achieved in a particularly efficient manner in that the coolant circuit has at least one switching valve for switching between the two refrigerant-coolant heat exchangers and / or for distributing the coolant to the two refrigerant-coolant heat exchangers.

For an advantageous gradation of the operating modes as a function of the ambient temperature, it is advantageous if the radiator of the coolant circuit has a bypass which can be opened by at least one change-over valve. For example, at moderate ambient temperatures, it may be sufficient to store the waste heat from components such as the electric motor and electronic components as well as the heat extracted from the vehicle interior in the coolant circuit, without releasing it via the radiator to the environment and using it when needed in the heating case.

Preferably, the coolant circuit has a single pump, with which both the heating operation and the cooling operation can be realized in an efficient manner.

list of figures

Hereinafter, an embodiment of the invention will be explained with reference to the drawings.

• 1 schematisch ein Heiz- und Klimatisierungssystem eines Fahrzeugs mit der erfindungsgemäßen Anbindung an das Wärmepumpensystem;
• 2 schematisch die erfindungsgemäße Durchströmung des Kühl- bzw. des Kältemittels durch das Wärmepumpensystem im Kälteanlagenbetrieb;
• 3 schematisch die erfindungsgemäße Durchströmung des Kühl- bzw. des Kältemittels durch das Wärmepumpensystem im Kälteanlagenbetrieb ohne im Radiator Wärme an die Umgebung abzugeben;
• 4 schematisch die erfindungsgemäße Durchströmung des Kühl- bzw. des Kältemittels durch das Wärmepumpensystem im Wärmepumpenbetrieb;
• 5 schematisch die erfindungsgemäße Durchströmung des Kühl- bzw. des Kältemittels durch das Wärmepumpensystem im Wärmepumpenbetrieb ohne im Radiator Wärme aus der Umgebung aufzunehmen;
• 6 schematisch die erfindungsgemäße Durchströmung des Kühl- bzw. des Kältemittels durch das Wärmepumpensystem bei der internen Wärmeübertragung innerhalb des Kältemittelkreislaufs zwischen der Hochdruck- und der Niederdruckseite.

Show it:

• 1 schematically a heating and air conditioning system of a vehicle with the inventive connection to the heat pump system;
• 2 schematically the flow according to the invention of the refrigerant or the refrigerant through the heat pump system in refrigeration system operation;
• 3 schematically the flow according to the invention of the refrigerant or the refrigerant through the heat pump system in refrigeration system operation without emitting heat in the radiator to the environment;
• 4 schematically the flow according to the invention of the refrigerant or the refrigerant through the heat pump system in heat pump operation;
• 5 schematically the flow according to the invention of the refrigerant or the refrigerant through the heat pump system in heat pump operation without heat in the radiator from the environment;
• 6 schematically the flow according to the invention of the refrigerant or the refrigerant through the heat pump system in the internal heat transfer within the refrigerant circuit between the high pressure and the low pressure side.

Detailed description of a preferred embodiment of the invention

For conditioning the air to be supplied into the passenger compartment is in the lower part of the 1 an air conditioning system is shown, which is designed for a combined operation in the refrigeration and heating mode and for a Nachheizmodus.

The air conditioning system has a housing with a cold air 14 and a hot air flow channel 16 and a refrigeration cycle 12 on. The refrigerant circuit consists of a compressor 1 , the condenser unit referred to as "Condenser" with a high-pressure accumulator, an expansion element and the evaporator referred to as "evaporator", wherein the condenser high-pressure side in the hot air flow channel 16 and the evaporator on the low pressure side in the cold air flow channel 14 is arranged. Depending on the operating mode, the air conditioned via the condenser or evaporator can be routed either into the passenger compartment or into the environment.

According to the invention, the refrigeration cycle additionally comprises a first refrigerant-refrigerant heat exchanger 2 on the low pressure side and a second refrigerant-refrigerant heat exchanger 3 on the high pressure side. The embodiment shown has for each refrigerant-refrigerant heat exchanger 2 . 3 one by means of a shut-off valve 10 lockable and openable bypass 26 on.

In the upper area of the 1 is the coolant circuit 28 represented, according to the invention by means of a corresponding valve 30 with both refrigerant-refrigerant heat exchangers 2 . 3 independently connectable. Further, as explained below, a mode is possible in which the coolant flow to the two refrigerant-refrigerant heat exchangers 2 . 3 is split. A pump 5 promotes the coolant and, in particular, depending on the design of the engine or vehicle, heat from an optional intercooler WCAC 6 and / or by an electric motor 7 and / or electronic components 8th on. Further, depending on the mode and circuit of the other valves 38 . 40 over a radiator 4 a heat transfer to the environment done.

A cooling mode is in 2 shown. To all figures is to mention that the dark arrows at the pump 5 and the radiator 4 the flow and at the valves indicate the barrier. As in 2 recognizable, the refrigerant-refrigerant heat exchanger 2 bypassed and by means of the refrigerant-coolant heat exchanger 3 can the refrigerant in the circuit 12 Dewatering or condensation heat in the coolant circuit 28 which in this case is so switched, the moreover heat from the heat sources 6 . 7 and 8th can be taken and over the radiator 4 can be discharged into the environment. In this mode, the bypass of the first refrigerant-refrigerant heat exchanger becomes 2 opened, which is not in operation in this case, so that unnecessary pressure loss can be avoided.

In the 3 illustrated mode of operation is different in that the radiator 4 does not flow through the switching valve 40 directly in the direction of the pump 5 and not to the radiator 4 is switched. This mode is suitable for moderate cooling, for example at ambient temperatures of about 5 to about 20 ° C, since in this case the capacity of the coolant circuit 28 for the waste heat not only of the heat sources 6 . 7 and 8th but also from the vehicle interior, via the heat exchanger 3 is recorded is sufficient. In addition, the in the coolant circuit 28 stored heat may be used at a later time by suitable switching the switching valves for heating.

In the 4 shown operating mode is suitable for heating at moderately lower ambient temperatures. In this case, the radiator 4 flows through to absorb heat from the environment. Heat is moreover from heat sources 6 . 7 and 8th recorded, and the valve 30 is also switched so that the coolant through the refrigerant-coolant heat exchanger 2 flows. Here, evaporation heat is transferred to the refrigerant in the refrigerant cycle 12 delivered to allow heating of the interior. In this mode, the bypass of the second refrigerant-refrigerant heat exchanger becomes 3 opened, which is not in operation in this case, so that unnecessary pressure loss can be avoided.

In the 5 The operating mode shown differs from the operating mode of 4 similar to the modes of the 2 and 3 , The radiator 4 is similarly bypassed and it is only the heat of the heat sources 6 . 7 and 8th This avoids problems caused by the icing of the radiator at very low ambient temperatures, which increases the overall performance of the heat pump system.

In 6 Finally, an operating mode is shown in which both refrigerant-refrigerant heat exchangers 2 . 3 be traversed by the coolant flow in the circuit 28 by means of the valve 30 split and in front of the pump 5 is brought together again. In the refrigerant-refrigerant heat exchanger 3 On the high pressure side, therefore, dewatering or condensation heat is released, and in the heat exchanger 2 evaporation heat is taken up on the low pressure side. The radiator 4 of the coolant circuit 28 is bypassed in this mode. As a result, indirectly via the coolant circuit 28 warmth between the high pressure and low pressure sides of the refrigerant circuit 12 transferred. There is also heat from the heat sources 6 . 7 and 8th added. Again, especially at low ambient temperatures, problems associated with icing of the radiator 4 be avoided. Further, efficient operation of the heat pump system is enabled by utilizing heat of vaporization at a temperature higher than ambient temperature, and thus increasing the refrigerant mass flow due to the higher suction density of the refrigerant. The same advantage applies to the operating mode of 5 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004001233 A1 [0005]
• US 2012/0183815 A1 [0005]

Claims (5)

Heat pump system for a vehicle having a refrigerant circuit (12), each having at least one refrigerant-refrigerant heat exchanger (2, 3) upstream and downstream of a compressor (1) and a coolant circuit (28) with at least one heat source, such as a radiator ( 4), an intercooler (6), an electric motor (7) and / or electronic components (8), characterized in that the coolant circuit (28) is selectively connectable with one or both refrigerant-coolant heat exchangers (2, 3). Heat pump system after Claim 1 , characterized in that at least one refrigerant-coolant heat exchanger (2, 3) has a closable bypass (26). Heat pump system after Claim 1 or 2 , characterized in that the coolant circuit (28) at least one switching valve (30) for switching between the refrigerant-refrigerant heat exchangers (2, 3) and / or for distributing the coolant to the two refrigerant-refrigerant heat exchangers (2, 3) having. Heat pump system according to one of the preceding claims, characterized in that the radiator (4) of the coolant circuit (28) has a by at least one switching valve (38, 40) to be opened by-pass. Heat pump system according to one of the preceding claims, characterized in that the coolant circuit (28) has a single pump.

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