Circulation arrangement

Abstract

A circuit arrangement (301) comprising a compressor (200), an evaporator (iV), a subcooler (SC) and a condenser (iC) in a refrigerant circuit, wherein a first circuit is connected to this via the evaporator (iV) and the subcooler (SC), in which an external heat exchanger (302) is arranged to allow flow through via a valve (25), wherein the external heat exchanger (302) is divided into at least two separately flowable parts (A1, A2), wherein the arrangement of the components in the circuit arrangement is such that the refrigerant is compressed by the compressor (200), condensed in the condenser (iC), then flows into the collector (201), is then subcooled in the subcooler (SC), is throttled to evaporation pressure in the expansion valve and evaporates in the evaporator (iV).

Description

Technical area

[0001] The invention relates to a circuit arrangement, in particular for cooling and / or heating motor vehicles. State of the art

[0002] Heat pump systems for motor vehicles are known, for example, from DE 35 14 781. This document discloses that ambient air is used as a heat source.

[0003] The document DE 100 29 934 discloses an air conditioning system with heat pump mode.

[0004] However, these are connected in a relatively complicated way and cause problems with the external heat exchanger when the heat exchanger freezes up, so that no air can flow through it.

[0005] In this case, a defrosting process must be carried out, so that heating is not possible in this operating situation. Description of the invention, task, solution, advantages

[0006] The object of the invention is to create an improved circuit arrangement that improves or even eliminates the disadvantages of the prior art. In particular, it is important to be able to operate the heating system continuously, even if defrosting is to take place in parallel.

[0007] This is achieved with the features of claim 1, according to which a circuit arrangement is created with a compressor, an evaporator, a subcooler and a condenser in a refrigerant circuit, wherein a first circuit is connected to this via the evaporator and the subcooler, in which first circuit an external heat exchanger is arranged so that it can flow through via a valve, wherein the external heat exchanger is divided into at least two separately flow-through parts, wherein the arrangement of the components in the circuit arrangement is such that the refrigerant is compressed by the compressor, condensed in the condenser, then flows into the collector, then subcooled in the subcooler, throttled to evaporation pressure in the expansion valve and evaporates in the evaporator.This allows the flow to be divided and distributed between the two parts, so that heating can be maintained via one of the two parts while the other part can be defrosted or vice versa.

[0008] It is advantageous if a branch line is connected in the flow direction between the evaporator and the subcooler via a valve, which is fed back into the circuit in the flow direction between the parts of the external heat exchanger.

[0009] It is also useful if the valve is a 4 / 2-way valve, which controls the flow direction of the two parts of the outdoor heat exchanger.

[0010] It is also advantageous if a second circuit is connected via the capacitor, in which a radiator is connected.

[0011] Furthermore, it is advantageous if a bypass is arranged parallel to two connections of the 4 / 2-way valve, which can be controlled by means of a valve.

[0012] It is also advantageous if the first and second circuits can be connected via two connections.

[0013] Furthermore, it is advantageous if additional heat sources can be arranged or connected in parallel to the evaporator.

[0014] It is also expedient if the additional heat source is assigned a pump in the flow path and in particular a bypass that can be controlled by means of a valve.

[0015] It is also advantageous if the additional heat source is assigned a valve in the flow path.

[0016] The refrigeration circuit's circuitry is simple, as no switching valves are required. The refrigeration circuit components are more flexible in their arrangement within the vehicle, as no air is required. This also allows for optimized line routing with respect to pressure drop.

[0017] By using a secondary circuit as the first circuit, flammable or toxic refrigerants can be used more easily, as there is no direct contact with the interior.

[0018] With a secondary circuit, additional heat sources can also be integrated with comparatively little effort.

[0019] Further advantageous embodiments are described by the following description of the figures and by the subclaims. Short description of the drawings

[0020] The invention will be explained in more detail below on the basis of at least one embodiment with reference to the drawings. They show: Fig. 1 an embodiment of a circuit arrangement according to the invention in a first circuit, Fig. 1a shows an embodiment of a circuit arrangement according to the invention in a first circuit with a refrigerant circuit shown, Fig. 2 an embodiment of a circuit arrangement according to the invention in a second circuit, Fig. 3 an embodiment of a circuit arrangement according to the invention in a third circuit, Fig. 4 an embodiment of a circuit arrangement according to the invention in a fourth circuit, Fig. 5 an embodiment of a circuit arrangement according to the invention in a fifth circuit, Fig. 6 an embodiment of a circuit arrangement according to the invention in a sixth circuit, Fig. 7 an embodiment of a circuit arrangement according to the invention in a seventh circuit, Fig. 8 an embodiment of a circuit arrangement according to the invention in an eighth circuit, and Fig. 9 an embodiment of a circuit arrangement according to the invention in a ninth circuit. Preferred embodiment of the invention

[0021] The Fig. Figure 1 shows a first exemplary embodiment of a circuit arrangement 301 according to the invention, which illustrates the principle of the split external heat exchanger 302 (A1, A2). The circuit arrangement 301 comprises an external heat exchanger 302 divided into two parts A1, A2, which can be geometrically separated from one another and, in any case, can be flowed through differently. These two parts A1, A2 of the external heat exchanger 302 can also be arranged together and, if necessary, mechanically connected, although the flow can occur independently of one another.

[0022] The circuit further comprises, starting from the two parts A1, A2 of the external heat exchanger, a 4 / 2-way valve 25 through which the two media flowing in lines 303 and 304 flow, thus diverting or controlling the fluid flows. After flowing through valve 25, the fluid flows through the evaporator iV. The refrigerant is evaporated in the evaporator iV, and the evaporating refrigerant cools the heat transfer medium. A pump 30 is then arranged in the direction of flow, which conveys the heat transfer medium. After the heat transfer medium, for example a coolant or refrigerant, has released heat to the refrigeration circuit in the evaporator iV, the main circuit 103 is divided into two partial flows 101 and 102 in the mixer 20. For this purpose, a valve 305 is provided as the mixer 20.

[0023] A smaller partial flow 102 flows through the subcooler SC, in which the liquid coolant or refrigerant is heated to a temperature above 0°C.

[0024] Subsequently, the partial flow 102 of the coolant or refrigerant is passed through the 4 / 2-way valve 25 to the part A1 of the external heat exchanger, which is then heated by the heat transfer medium, the coolant or refrigerant, to temperatures above 0°C.

[0025] This allows ice, which is blocking the air side of section A1 of the outdoor heat exchanger and hindering heat transfer, to melt. A1 is thus defrosted, allowing air to flow through it again, and can once again fulfill its function.

[0026] Part A1 of the outdoor heat exchanger 302 is preferably sealed off on the air side so that no heat can be released into the ambient air. This sealing can advantageously be achieved by at least one flap or similar device. A flap can be arranged upstream and / or downstream of the heat exchanger A1 to prevent air flow, allowing the defrosting process of the heat exchanger to be accelerated.

[0027] The flow rate of the heat transfer medium from 102 is preferably adjusted or regulated so that an optimal power output to part A1 is achieved.

[0028] The partial flows of the heat carrier 101 and 102 are then reunited in the node 104 and then flow to the part A2 of the external heat exchanger.

[0029] The temperature of the heat transfer medium, such as the coolant or refrigerant, after node 104 is colder than the ambient temperature. Therefore, heat is extracted from the environment and added to the heat transfer medium. This may result in progressive icing of part A2. The coolant or refrigerant then flows through the 4 / 2-way valve to the evaporator iV, where the heat absorbed from the environment is transferred to the refrigeration circuit.

[0030] In the condenser iC, heat is transferred from the refrigeration circuit 310 to the small coolant circuit 110, which transports the heat to the radiator HK, which in turn heats the cabin supply air for the vehicle interior.

[0031] The integration of the heat exchangers condenser iC, evaporator iV and subcooler SC into the refrigeration circuit 112 is in Fig. 1a shown.

[0032] The refrigeration circuit 112 is in Fig. 1a is represented by the dashed line. The refrigerant is compressed by the compressor 200, condensed in the condenser iC, and flows into the receiver 201. It is then subcooled in the subcooler SC, throttled to evaporation pressure in the expansion valve, which is preferably a thermostatic expansion valve, and evaporated in the evaporator iV.

[0033] A connection with a low-pressure collector and orifice is also conceivable, with the collector located between the evaporator and the compressor.

[0034] The refrigeration circuit 112 is shown in the following circuits of the Fig. 2 to 9 are integrated in the same way and are therefore no longer presented separately.

[0035] The Fig. Figure 2 shows how the functions of A1 and A2 are reversed by switching the 4 / 2-way valve 25. It can be seen that the arrows representing the flow through the two heat exchangers A1, A2 are pointing from Fig. 1 and Fig. 2 are reversed. Valve 25 is also in a crossover position in this example.

[0036] Instead of the 4 / 2-way valve, a different valve can be designed or used so that the function of switching the flow directions in the circuit is ensured.

[0037] Accordingly, an air-side shutoff must also be switched over, meaning that during this defrosting phase, part A2 of the outdoor heat exchanger 302 is preferably shut off on the air side so that no heat can be released into the ambient air. This shutoff can advantageously be achieved by at least one flap or similar device. A flap can be arranged upstream and / or downstream of the heat exchanger A2 to prevent air flow, so that the defrosting process of the heat exchanger A2 can be carried out more quickly.

[0038] Since either the first part A1 or the second part A2 can be defrosted alternately, continuous operation of the heat pump is possible, with the two halves of the outdoor heat exchanger 302 alternately absorbing heat from the environment or being defrosted.

[0039] Especially at very low temperatures, the icing of the heat exchanger 302 is not so serious, but a high exchange rate of the external heat exchanger would be desirable to achieve high heating output.

[0040] A possible connection for this is shown in the Fig. 3. This merely requires an addition to the circuit according to the Fig. 2 is provided by a switching valve 21, which connects or short-circuits the two connections 311,312 on the left side of the 4 / 2-way valve.

[0041] Partial mass flow 102 is adjusted to achieve the subcooling required for stable operation of the refrigeration circuit. It is typically significantly smaller than the mass flow in 101. By opening switching valve 21, the coolant or refrigerant mass flow is divided into the two partial mass flows 105 and 106, so that heat is now absorbed from the environment in both heat exchangers A1 and A2. This achieves a particularly high heat pump performance. It can be seen that the bypass through valve 21 can be controlled in such a way that both parts of the outdoor heat exchanger 302, or A1 and A2, can be operated in parallel.

[0042] A heating and cooling system for a motor vehicle can also advantageously fulfill additional functions, such as cooling and reheating. Furthermore, it may be desirable to integrate additional heat sources, such as electronics cooling, engine cooling, etc., into the circuit to make these heat sources usable for the heat pump.

[0043] The Fig. Figure 4 shows the circuit arrangement in the so-called reheat mode. The heat transfer fluid cooled in the evaporator iV flows to the cooling element 320, which cools the cabin supply air and dehumidifies it. The cooling element 320 is connected in parallel to the evaporator iV with a bypass 321 and a pump 32 upstream of the cooling element 320.

[0044] The heat released by the refrigeration circuit 112 generally does not correspond to the heat demand for tempering the supply air. If the heat supply exceeds the heat demand, it is possible to direct a partial flow 107 from 110 to the outdoor heat exchanger 302, where it releases the excess heat to the environment. The proportion of the partial flow can be controlled by the mixer valve 22, which is arranged between the subcooler SC and the condenser iC. The mixer valve 22 controls the bypass 108 in parallel with the radiator HK and the condenser iC. The radiator HK is also connected to part A1 of the outdoor heat exchanger 302 at node 322.

[0045] If no heating power is required at all, the radiator HK can be shut off on the air side, and the entire mass flow 110 can be directed to the outdoor heat exchanger. This then represents pure cooling operation.

[0046] The Fig. 5 shows an operating mode for a case where the heat demand is smaller than the heat supply of the variant in Fig. 4. There is no branching of the heating circuit 110, which means that all waste heat from the refrigeration circuit should be used to heat the supply air flow.

[0047] To provide additional heat, the environment is also used as a heat source. Part of the coolant flowing through the evaporator iV dehumidifies the cabin air in the cooling body 320, while another part flows to the external heat exchanger and extracts heat from the environment. This allows the refrigeration circuit to absorb more heat and provide correspondingly more heating power.

[0048] For heat absorption from the environment, the Fig. 1 to 3 explained operating modes advantageous, Fig. 5 shows an example of the Fig. 2, in which A2 extracts heat from the environment while A1 is defrosted.

[0049] If the ambient temperature is below the freezing point of water, the heat transfer fluid temperatures at the evaporator are below 0°C, so that icing could occur in the heat sink 320. If dehumidification is still desired (e.g., in recirculation mode), the mixing valve 24 and the pump 32 can be used to create circulation via the bypass 321, thus keeping the flow of the heat sink above 0°C.

[0050] The Fig. 6 to 8 show the 3 heat pump operating modes in a system with AC and Reheat option according to the Fig. 1 to 3.

[0051] Furthermore, it is possible to use additional heat sources 111 for heating, for example, heat generated during the cooling of power electronics or electric motors. This heat can, in principle, be integrated at any point in the coolant circuit as a parallel or serial circuit. If the heat source has a relatively high temperature and requires constant cooling, then an integration as in Fig. 9. The additional heat source Q111 is arranged parallel to the evaporator, and the fluid flow can be controlled by valve 125. This allows the heat source Q111 to be cooled in both AC and heat pump mode. Even when the refrigeration circuit is switched off, heat can be transported from the heat source Q111 to the outdoor heat exchangers A1, A2.

[0052] An embodiment of the circuit arrangement according to the invention has the following features: 1. The system contains a refrigeration circuit with compressor, condenser, subcooler, expansion device, receiver and at least one evaporator. 2. The outdoor heat exchanger, which is in contact with the ambient air and absorbs heat from the environment during heating operation, is divided into at least two parts. These should preferably be of equal size. 3. The parts can be flowed through sequentially or independently. 4. There is an operating mode in which one part is thawed by supplying it with heat from the subcooling of the refrigerant (high pressure), while the other part extracts heat from the environment and supplies it to the refrigeration circuit in the low pressure part. 5. There is an analogue operating mode in which the function of the two heat exchangers is reversed. 6. There is an operating mode in which both outdoor heat exchangers absorb heat from the environment in order to provide maximum heating output.

[0053] Further functions, such as the connection of additional heat sources as described above, can be added in further embodiments.

Claims

[1] Circuit arrangement (301) with a compressor (200), an evaporator (iV), a subcooler (SC) and a condenser (iC) in a refrigerant circuit, wherein a first circuit is connected to the latter via the evaporator (iV) and the subcooler (SC), in which first circuit an external heat exchanger (302) is arranged so that it can flow through via a valve (25), wherein the external heat exchanger (302) is divided into at least two separately flow-through parts (A1, A2), wherein the arrangement of the components in the circuit arrangement is such that the refrigerant is compressed by the compressor (200), condensed in the condenser (iC), then flows into the collector (201), then subcooled in the subcooler (SC), throttled to evaporation pressure in the expansion valve and evaporates in the evaporator (iV). [2] Circuit arrangement according to claim 1, characterized bythat a branch line is connected in the flow direction between the evaporator and the subcooler via a valve (20), which is fed back into the circuit in the flow direction between the parts (A1, A2) of the external heat exchanger (302). [3] Circuit arrangement according to one of the preceding claims, characterized by that the valve (25) is a 4 / 2-way valve which controls the flow direction of the two parts (A1,A2) of the external heat exchanger (302). [4] Circuit arrangement according to one of the preceding claims, characterized by that a second circuit is connected via the capacitor (iC), in which a radiator (HK) is connected. [5] Circuit arrangement according to one of the preceding claims, characterized by that a bypass is arranged parallel to two connections of the 4 / 2-way valve, which bypass can be controlled by means of a valve (21). [6] Circuit arrangement according to one of the preceding claims, characterized by that the first and second circuits can be connected via two connections. [7] Circuit arrangement according to one of the preceding claims, characterized by that further heat sources (320, Q) can be arranged or connected in parallel to the evaporator (iV). [8] Circuit arrangement according to claim 7, characterized by that the further heat source is assigned a pump (32) in the flow path and in particular a bypass (321) which is controllable by means of a valve (24). [9] Circuit arrangement according to one of the preceding claims 7 or 8, characterized by that the heat source (320, Q) is assigned a valve in the flow path.

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