Heat pump device

Abstract

The present invention relates to a heat pump device (1) for heating and / or cooling a building. The heat pump device (1) comprises a housing (2) which surrounds an interior. The interior is subdivided into a first space (R1) and a second space (R2). An evaporator (16) for transferring heat from an ambient medium to the refrigerant is located in the first space (R1). A compressor (20) for compressing the refrigerant is located in the second space (R2). An air shaft (4) is formed in the second space (R2) and has a top opening and a bottom opening in the housing (2). A heat sink (11) for cooling the inverter (14) is located on an inner wall of the air shaft (4).

Description

[0001] HEAT PUMP DEVICE

[0002] Field of the invention

[0003] The present invention relates to a heat pump device for heating and / or cooling a building.

[0004] Background of the invention

[0005] Modern heat pumps are characterized by their high efficiency, making them particularly attractive for heating and / or cooling a building from both an ecological and economic perspective. Heating with ambient heat is, on the one hand, climate-friendly. On the other hand, many energy suppliers have been offering special heat pump tariffs for several years that are more financially attractive than a standard electricity tariff.

[0006] A heat pump typically includes a compressor for compressing a refrigerant. Such a compressor is usually controlled by an inverter, which can, for example, control the compressor's power or speed. An inverter generates heat during operation, which can be dissipated via a heat sink, for example. The inverter and other components can generate heat, which can lead to an uneven temperature distribution within the heat pump housing. In unfavorable cases, this can also cause humidity to condense on cooler components of the heat pump. This can increase the risk of corrosion or an electrical short circuit.

[0007] Furthermore, it is known that inverters, such as a power inverter, generate heat that must be dissipated. For example, EP 3 216 330 A1 discloses an inverter for a photovoltaic system, comprising a housing with a chamber and a cooling air duct formed in the chamber for passing ambient air as cooling air for electrical and / or electronic components of the inverter, which are arranged along the cooling air duct. The cooling air duct is guided through the housing from an air inlet opening to an air outlet opening.

[0008] Utility model DE 20 2019 100 059 Ul discloses a heat exchanger unit with a heat exchanger and fan in a housing. Outside air is drawn in through a first air inlet, which is provided with a protective grille. This air flows through the heat exchanger, transfers or absorbs its heat to a refrigeration circuit or a heat transfer medium, and then flows through a first, horizontal air duct. Behind the fan, the now cooled or heated air exits the housing of the heat exchanger unit through the air outlet, which is protected by a protective grille.

[0009] US Patent No. 11,226,119 B2 relates to a heat exchanger unit connected to a refrigerant line containing refrigerant. The heat exchanger unit includes a plurality of heat sources, each of which has a different amount of heat generation, and a plurality of cooling units, each configured to cool one of the plurality of heat sources. The cooling schemes of the plurality of cooling units differ depending on the amount of heat generated by the plurality of heat sources.

[0010] Further generic heat pump devices are disclosed in JP 2003-214 659 A, JP 2017-101 886 A, JP 2018-128 232 A and US 11,339,977 B2. The problem underlying the invention

[0011] The present invention is therefore based on the object of overcoming the problems known in the prior art and providing a heat pump device that is improved over the prior art. In particular, an arrangement is to be created in which the formation of condensation in the housing of a heat pump device is reduced or largely avoided. Furthermore, the cooling of components that generate heat is to be improved.

[0012] Inventive solution

[0013] The object is achieved according to the invention by a heat pump device for heating and / or cooling a building according to claim 1. Preferred embodiments of the present invention are the subject of the dependent claims, the attached drawings and the following description of exemplary embodiments.

[0014] The heat pump device can, for example, be designed as an outdoor unit (ODU) of a heat pump system. Such an ODU can preferably be arranged outside a building, for example, in front of the building, on a wall, or on a roof of the building, especially if the outside air serves as the ambient medium from which heat is to be absorbed. Depending on the outside temperature, the outside air can contain more or less moisture. In unfavorable cases, this moisture can condense on cooler components of the heat pump device, which could lead, for example, to corrosion or electrical short circuits.

[0015] The heat pump device contains at least part of a refrigerant circuit. Accordingly, the heat pump device can comprise multiple heat exchangers, refrigerant lines, expansion valves, switching valves, a compressor, an inverter for operating the compressor, and other electronic components for controlling and / or regulating the operation of the heat pump device. The components of the heat pump device can have different temperatures during operation.

[0016] In this application, an "evaporator" refers to a heat exchanger, particularly between air and refrigerant, which is used to evaporate the refrigerant during normal heating operation of the heat pump device. If the cycle is reversed, for example, for actively defrosting the evaporator or for cooling the building, this heat exchanger can be operated as a condenser. Accordingly, the function of the heat exchanger operating as a condenser during heating operation can be changed to that of an evaporator.

[0017] In particular, the compressor and other electronic components can generate heat during operation. This heat must generally be dissipated to prevent the components from overheating. In some designs, for example, the heat from the inverter can be used for heating via a heat exchanger, which can improve the efficiency of the heat pump.

[0018] The heat pump device comprises a housing enclosing an interior space. The housing is usually essentially cuboidal or cylindrical and may have a floor, outer side walls, a ceiling, and / or a lid, some of which may be removable. Insulating panels may be provided on the outer walls or ceiling for acoustic or thermal insulation.

[0019] The interior space is divided into a first room and a second room. For example, one or more partition walls can be arranged within the interior space to divide the space. This can, for example, create separate sub-rooms (first and second rooms) with different temperatures and / or different airflows.

[0020] The first chamber can, for example, serve as a passage for a first airflow. In particular, the evaporator is located in the first chamber to transfer heat from the ambient medium, usually air, to the refrigerant. A fan can generate the first airflow in or through the first chamber, thus improving heat transfer from the ambient medium to the refrigerant. The first chamber can also be referred to as the evaporator chamber, for example.

[0021] A compressor for compressing the refrigerant is located in the second chamber. An inverter for controlling the compressor is also located in the second chamber. The second chamber can also be referred to as the electronics or machine room of the heat pump device, since components of the refrigerant circuit, as well as electronic components and the like, are located here.

[0022] According to the invention, an air duct with an upper opening and a lower opening is formed in the housing. The air duct is preferably arranged in the second space. A second air stream can flow through the air duct. This second air stream can be actively generated by a second fan. Alternatively or additionally, the second air stream can also be generated by a chimney effect. The chimney effect refers to a natural air flow that occurs when warm air rises and cold air flows in to replace it. To promote the chimney effect, the air duct can preferably be arranged essentially vertically. However, it is not absolutely necessary for the air duct to have a straight course. To achieve a chimney effect, it may be sufficient for the upper opening to be arranged higher in the direction of gravity than the lower opening.Accordingly, the lower opening can be referred to as the air inlet opening and the upper opening as the air outlet opening. According to the invention, a heat sink for cooling the inverter is arranged on an inner wall of the air shaft. The inner wall is referred to here in particular as an inner side of a wall separating the air shaft from the second chamber.

[0023] The heat sink is in thermally conductive contact with the inverter. For example, a surface of the inverter can be in thermal contact with a surface of the heat sink. The heat sink can also preferably be thermally conductively connected to a wall of the air duct to transfer the heat absorbed by the inverter to the air duct.

[0024] In a preferred embodiment, the wall of the air duct can be arranged between the heat sink and the inverter. In other words, the inverter can be arranged, for example, on an outer side of the air duct, while the heat sink with a corresponding shape is arranged on the inner side of the air duct. Particularly preferably, the inverter is arranged on an outer wall of the air duct facing the second chamber. Thus, an electrical connection between the inverter and a compressor arranged in the second chamber can be established particularly easily, while the inverter can be efficiently cooled by the heat sink arranged in the air duct.

[0025] According to the invention, the air shaft is fluidly connected to the second room via the upper opening and the lower opening.

[0026] This can be achieved by creating a chimney effect that circulates the air inside the second room. This advantageously achieves a more homogeneous temperature distribution inside the enclosure. Without the air duct or active air turbulence via a fan, a layer of cold air can build up inside the second room at the bottom of the enclosure and warm air at the ceiling. The colder air at the floor can cause condensation of air humidity there. By avoiding this layering of air, the occurrence of condensation can be prevented.

[0027] According to a preferred embodiment, a second fan can be arranged in the air duct to generate an airflow through the air duct. This second fan can, in particular, amplify the second airflow generated by the natural chimney effect. This can improve the cooling of the inverter and the circulation of the air in the second chamber, thus achieving a more homogeneous temperature distribution in the second chamber. This can prevent the formation of condensation in the area of ​​the floor in the housing.

[0028] Preferably, additional power electronic components of the heat pump device can be arranged on the outer wall of the air shaft facing the second room and / or on the inner wall of the air shaft. Furthermore, a diffuser can be arranged between the second fan and the heat sink.

[0029] A preferred heat sink may, in particular, comprise fins and / or air baffles. The fins may increase the surface area of ​​the heat sink, allowing the heat sink to dissipate more heat into the surrounding air. The air baffles may improve the interaction between the air flow in the air duct and the heat sink, thus also improving the cooling effect of the heat sink.

[0030] The heat sink is preferably positioned closer to the lower opening than the upper opening. This allows the heat sink to advantageously come into contact with cooler air, which subsequently heats up and rises upwards, creating a chimney effect in the air shaft. Brief description of the drawings

[0031] Further advantageous embodiments are described in more detail below with reference to an embodiment shown in the drawings, to which the invention is not limited, however.

[0032] They show schematically:

[0033] Fig. 1 illustrates a heat pump system according to an embodiment of the present invention.

[0034] Fig. 2 illustrates a plan view of a heat pump device according to an embodiment of the invention.

[0035] Fig. 3 shows a perspective view of a heat pump device according to an embodiment of the invention.

[0036] Fig. 4 shows an internal view of an air shaft in a heat pump device according to an embodiment of the invention.

[0037] Fig. 5 shows a perspective view of the air shaft from Fig. 4.

[0038] Detailed description of the invention based on exemplary embodiments

[0039] In the following description of a preferred embodiment of the present invention, like reference numerals designate like or comparable components.

[0040] Fig. 1 illustrates an embodiment of a heat pump system 100 for heating or cooling a building. The heat pump system 100 functions in principle like a known heat pump system. The respective modes of operation of the compressor 20, condenser 13, expansion valves EVI, EV2, evaporator 16, and collectors 18, 19 are known to those skilled in the art and will not be described in detail here. The heat pump system 100 of Fig. 1 comprises a refrigerant circuit with a compressor 20, a multi-way valve 12, a condenser 13, a first expansion valve EVI, an internal heat exchanger 15, an inverter 14, a second expansion valve EV2, an evaporator 16, a first collector 18, and a second collector 19. Furthermore, a plurality of temperature sensors 0 and pressure sensors p are arranged in the refrigerant circuit 30.

[0041] The lines between the individual components of the refrigerant circuit 30 are labeled A to H. Line A connects the compressor 20 to the multi-way valve 12, which serves, on the one hand, to switch between sub-circuits and, on the other hand, can reverse the circuit, e.g., to switch from heating to cooling or to actively defrost the evaporator 16.

[0042] Line C connects the multi-way valve 12 to the condenser 13. The condenser is a heat exchanger where heat is transferred from the refrigerant in the refrigeration circuit to a heat transfer medium in a heating circuit. The heat transfer medium flows via a flow line VL to a thermal load 30, such as a heating circuit in a building.

[0043] The heat transfer medium flows back to the condenser 13 via a return line (RL). In the illustrated design, a temperature sensor (0) for measuring the return temperature is located in the return line (RL). Alternatively or additionally, a temperature sensor (0) for measuring the flow temperature can also be located in the flow line (VL).

[0044] Line D connects the condenser 13 to the first expansion valve EVI. Line E connects the first expansion valve EVI to the internal heat exchanger 15, where heat is exchanged with the circuit formed by lines B, J, and K. Line F connects the internal heat exchanger 15 to the second expansion valve EV2. Line G connects the second expansion valve EV2 to the evaporator 16. A fan 17 is arranged on the evaporator 16 to supply the evaporator 16 with fresh air. During heating operation, the evaporator 16 can become very cold, so that, for example, humidity can condense and freeze on the fins of the evaporator 16, forming frost and / or ice there, which must be defrosted once it reaches a certain level of icing.

[0045] Line H connects the evaporator 16 again to the multi-way valve 12. Line B connects the multi-way valve 12 to the second collector 19. Line K connects the second collector 19 to the internal heat exchanger 15. Line J connects the internal heat exchanger 15 to the first collector 18, which in turn is connected to the compressor 20.

[0046] Line E (return) to the internal heat exchanger 15 and line F (supply) from the internal heat exchanger 15 are defined as the primary circuit of the internal heat exchanger 15. Line K (return) to the internal heat exchanger 15 and line J (supply) from the internal heat exchanger 15 are defined as the secondary circuit of the internal heat exchanger 15. The return K is connected to the switching valve 12 via the second collector 19. The supply J is connected to the return of the compressor 20 via the first collector 18.

[0047] The inverter 14 serves to control the compressor 20. According to the invention, the inverter 14 is connected to a heat sink in a heat-conducting manner, as described below with reference to Fig. 2.

[0048] Fig. 2 shows a schematic plan view of a heat pump device 1 according to an embodiment of the present invention. The heat pump device 1 comprises a housing 2 surrounding an interior space. A partition wall 3 divides the interior space into a first space R1 and a second space R2.

[0049] The function of the heat pump device 1 and its components is essentially identical to that of the heat pump system 100 described with reference to Fig. 1. In particular, the compressor 20, the condenser 13, the evaporator 16 with fan 17, and the inverter 14 of the heat pump device 1 in Fig. 2 function as in the heat pump system 100 of Fig. 1.

[0050] The first chamber RI has a first opening and a second opening. The first opening is formed here in the housing 2 between an outer wall, a base, and a cover of the housing 2 and the partition wall 3. The evaporator 16, through which a first air stream LI flows, is arranged in the first opening. In the embodiment shown, the first opening is completely occupied by the evaporator 16; see also Fig. 3.

[0051] The first air flow LI is generated by one (or more) fans 17 arranged in the first chamber RI. The first opening of the first chamber RI serves as the air inlet for the first air flow LI, and the second opening of the first chamber RI serves as the air outlet for the first air flow LI. For example, Fig. 3 shows a perspective view of the second opening of the first chamber RI. The second opening is defined here by the floor, the outer wall, and the cover of the housing 2, as well as the partition wall 3.

[0052] The second chamber R2 contains the condenser 13 for condensing the refrigerant, the compressor 20 for compressing the refrigerant, and the inverter 14, as well as lines for the refrigerant (not shown). The second chamber is also referred to as the machine room, since further electronic components for operating the heat pump device 1 can also be arranged there. A vertically aligned air shaft 4 with a square cross-section is arranged in the second chamber R2. In other designs, however, the cross-section can also be, for example, circular, elliptical, trapezoidal, or polygonal. Crucial to the function of the air shaft 4 is that it has a first lower opening and a second upper opening, which are each fluidly connected to the second chamber R2.According to the invention, the chimney effect creates a natural air flow in the air shaft 4, which leads to a mixing of cold and warm air in the second room R2, so that a more homogeneous temperature distribution can be achieved, whereby condensation of air humidity on the bottom of the housing 2 is reduced or completely prevented.

[0053] In Fig. 2, the air duct 4 is arranged flush with the partition wall 3. The partition wall 3 can be an outer wall of the air duct 4. In alternative embodiments, however, the air duct can also be arranged freely within the second space R2 without contact with an outer wall of the housing 2 or the partition wall 3. More preferably, the air duct 4 can be arranged in a corner of the housing 2. The arrangement of the air duct 4 can be determined depending on the available space and the like.

[0054] The inverter 14 is arranged on a surface of the air duct 4 facing the interior of the second space R2. One surface of the inverter 14 is thermally conductively connected to the outer surface of the air duct 4. A heat sink 11 with a plurality of fins is arranged on a corresponding inner surface of the air duct 4. The fins are aligned vertically so that they are in an air flow in the air duct. The heat sink 11 is thermally conductively connected to the inverter 14 via the wall of the air duct 4. For this purpose, the wall of the air duct 4 is preferably made of a material with good thermal conductivity, for example a metal such as aluminum or a suitable sheet steel or the like. To improve the thermal conductivity, a thermally conductive foil and / or thermally conductive paste can be arranged between the wall and the heat sink 11 and / or between the wall and the inverter 14.

[0055] The heat sink 11 is heated by the inverter 14 during operation. The heat sink 11 heats the surrounding air via its fins, which then rises in the air duct 4, drawing cooler air in its wake. This creates a natural airflow in the air duct 4. The air duct 4 is connected to the second room R2 at a lower and an upper opening. Thus, the natural airflow in the air duct 4 causes the air in the second room R2 to circulate, homogenizing the temperature distribution in the second room R2.

[0056] The natural airflow in the air shaft 4 can be amplified by an additional second fan 7. The second fan is preferably arranged so that the axis of rotation is vertical, as schematically illustrated in Fig. 2 by the blades of the fan 7. The axis of rotation of the second fan 7 is thus perpendicular to the axis of rotation of the first fan 17. Accordingly, the second airflow in the air shaft 4 also runs perpendicular to the first airflow LI.

[0057] The lower opening of the air duct 4 can be designed as a flat slot near the bottom of the housing 2, so that mainly air from a cool, flat air layer near the floor is sucked into the air duct 4.

[0058] Accordingly, the upper opening of the air shaft 4 may preferably be formed as a shallow slot near the ceiling of the housing 2, so that the heated air comes into contact with the ceiling of the housing 2, thereby cools down and falls back towards the floor.

[0059] Furthermore, air baffles can be arranged in the air shaft 4 and / or in the housing 2 to promote air circulation in the second room R2. This preferably allows a more uniform temperature distribution to be achieved more quickly. Condensation of air humidity in cool areas of the second room R2 can thus be effectively prevented.

[0060] Fig. 3 shows a perspective view of a heat pump device 1, which essentially corresponds to the diagram shown in Fig. 2. The heat pump device 1 shown here is designed as a so-called outdoor unit.

[0061] To illustrate the components arranged in the housing 2, parts of the housing have been hidden in the illustration in Fig. 3. The partition wall 3 is formed with a bend between the sub-chambers RI and R2. In the first chamber RI, the evaporator 16 is arranged between the partition wall 3 and a lateral outer wall of the housing. Approximately centrally in the first chamber, two fans 17 are arranged to generate the first air flow LI, indicated by an arrow, through the first chamber RI and through the evaporator 16.

[0062] The second room R2 contains a variety of components and electronic parts, not all of which are described in detail here. Shown in Fig.

[0063] 3, among other things, the compressor 20 and the condenser 13, which serves as a heat exchanger to a heating circuit that can be coupled to the heat pump device 1.

[0064] The air shaft 4, which here has a substantially square cross-section, is formed on a section of the partition wall 3. The lower opening to the second space R2 is covered by the compressor 20 and the condenser 13 in the illustration in Fig. 3. The upper opening of the air shaft 4 (at the reference symbol

[0065] 4 in Fig. 3) is formed close to a ceiling or lid of the housing 2, which is hidden for better visibility. The inverter 14 is arranged on an outer wall of the air shaft 4 in the second room R2. The corresponding heat sink 11 is arranged in the interior of the air shaft 4, as shown in Fig. 4. Above the inverter 14, a number of further electronic components 5 to be cooled are arranged on the air shaft 4. These components can be, for example, chokes and / or interference suppressors. Thus, the heat from the further electronic components 5 can also be distributed over the entire second room R2 via the air shaft 4.

[0066] Fig. 4 and Fig. 5 each show views of an assembly consisting of a section of the partition wall 3 and an outer wall of the air duct 4. These views illustrate where the heat sink 11 is located inside the air duct 4 and where the inverter 14 is located outside the air duct 4. The outer wall of the air duct 4 is made of a thermally conductive material so that the heat generated by the inverter 14 during operation is transferred to the heat sink 11.

[0067] As shown in Fig. 4, a fan 7 is arranged below the heat sink 11, which has a plurality of vertically arranged fins. This fan amplifies the air flow L2 indicated by the arrows through the air duct 4. Furthermore, a diffuser 6 is arranged between the fins of the heat sink 11 and the fan 7. This diffuser distributes the drawn-in air evenly across the fins and can thus improve the cooling effect of the heat sink 11.

[0068] In Fig. 5, the inverter 14 is arranged on a wall of the air duct 4 facing the interior space R2. The other electronic components 5 have been omitted from this illustration. The two arrows L2 mark the lower opening as the air inlet from the second space R2 into the air duct 4 and the upper opening of the air duct 4 as the air outlet to the second space R2. On the inside of the air duct 4, as shown in Fig. 4, the heat sink 11 is arranged exactly where the inverter 14 is located on the outside, so that the heat from the inverter 14 can be efficiently transferred to the air flow L2 in the air duct 4. The features disclosed in the above description, the claims, and the drawings can be important both individually and in any combination for the implementation of the invention in its various embodiments.

Claims

PATENT CLAIMS 1. A heat pump device (1) for heating and / or cooling a building, comprising: a housing (2) surrounding an interior space, the interior space being divided into a first space (RI) and a second space (R2); at least part of a refrigerant circuit in which a refrigerant circulates, comprising: an evaporator (16) arranged in the first space (RI) for transferring heat from an ambient medium to the refrigerant; a compressor (20) arranged in the second space (R2) for compressing the refrigerant; and an inverter (14) for controlling the compressor (20); a first fan (17) for generating a volume flow (LI) of the ambient medium in or through the first space (RI), wherein: an air shaft (4) with an upper opening and a lower opening is formed in the housing (2); a heat sink (11) for cooling the inverter (14) is arranged on an inner wall of the air shaft (4);and the air shaft (4) is fluidly connected to the second space (R2) via the upper opening and the lower opening; 2. Heat pump device (1) according to claim 1, wherein the inverter (14) is arranged on an outer wall of the air shaft (4) facing the second space (R2).

3. Heat pump device (1) according to claim 1 or 2, further comprising: a second fan (7) arranged in the air shaft (4) for generating an air flow (L2) through the air shaft.

4. Heat pump device (1) according to one of the preceding claims, wherein further power electronic components of the heat pump device (1) are arranged on the outer wall of the air shaft (4) facing the second space (R2) and / or on the inner wall of the air shaft (4).

5. Heat pump device (1) according to claim 3, wherein a diffuser is arranged between the second fan (7) and the heat sink (11).

6. Heat pump device (1) according to one of the preceding claims, wherein the heat sink (11) has fins and / or air baffles.

7. Heat pump device (1) according to one of the preceding claims, wherein the heat sink (11) is arranged closer to the lower opening than to the upper opening.

8. Heat pump device (1) according to one of the preceding claims, wherein the air shaft (4) runs vertically in the housing (2).

9. Heat pump device (1) according to one of the preceding claims, further comprising: a partition wall (3) for separating the first space (RI) from the second space (R2), wherein the air shaft (4) runs separately from the partition wall (3) in the second space (R2).

Images