heat pump

Abstract

Heat pump with a heating circuit, in particular for hot water preparation, wherein at least one heating element (7), in particular at least one electric heating element, is installed in the heating circuit, which is housed in a casing (3), wherein the casing (3) has a cylindrical base body (9) and at least two connections for connecting the casing to the heating circuit of the heat pump, wherein a first connection forms a fluid inlet (11) and a second connection forms a fluid outlet (13) for a heating fluid, in particular heating water, characterized in that the casing (3) is formed in one piece and has a transition contour (21) between the base body (9) and the fluid outlet (13), which tapers continuously from the base body (9) of the casing (3) to the fluid outlet (13) of the casing (3) to generate a homogeneous fluid flow in the casing (3).

Description

[0001] The invention relates to a heat pump according to the preamble of claim 1.

[0002] Housings of the type discussed here are known, for example, from DE 10 2009 044 566 A1. These housings serve to accommodate at least one heating element, and in particular a so-called electric heating element. Such heating elements are integrated into the heating circuit of heat pumps to support heating operation at very low outside temperatures, especially those below -5°C, and thus to achieve comfortable hot water supply. Water temperatures of 60°C are often desired at the tap, which conventional air-source heat pumps generally cannot achieve without support at low outside temperatures. The heating element arranged in the housing also serves as a short-term emergency heating system in the event of heat pump malfunctions. The housing has a first connection, designed as a fluid inlet, and a second connection, designed as a fluid outlet, for supplying a heating fluid.The heating fluid flows through the fluid inlet into the interior of the housing, which typically has a substantially cylindrical base. Inside the housing, the heating fluid flows around the heating element(s), if multiple elements are used, and then flows back into the heating circuit through the fluid outlet and connected lines.

[0003] Document US 7,574,987 B2 relates to a device for heating the coolant in a motor vehicle in order to heat the vehicle's engine.

[0004] The housings known from the prior art typically consist of several components, such as the base, bottom, cover, and fluid connections, which are elaborately welded or soldered together to achieve the necessary tightness, corrosion resistance, and temperature resistance. Disassembly of the individual components of the housing, for example for maintenance or repair purposes, is neither provided for nor possible with the known housings. A further disadvantage of the known housings for accommodating the heating elements of a heat pump circuit arises from the fact that the fluid connections, in the form of essentially cylindrical extensions, are simply soldered to corresponding openings in the cover of the base, resulting in a sharp-edged flow geometry. This sharp-edged deflection leads to turbulent, non-homogeneous flow, which should be avoided.Particularly when using components downstream of the housing, such as flow sensors, etc., turbulent flows are disadvantageous because these components require a homogeneous flow for proper function.

[0005] The object of the present invention is therefore to create a heat pump which, on the one hand, is optimized with regard to the flow properties of the heating fluid and, on the other hand, includes simple and cost-effective manufacturing and easy access for cleaning, maintenance and repair purposes.

[0006] To solve the aforementioned problem, a heat pump with the features of claim 1 is proposed. The heat pump comprises a heating circuit, in particular for domestic hot water preparation. At least one heating element, in particular at least one electric heating element, is integrated into the heating circuit. The at least one heating element is housed in a casing. The casing has a cylindrical base and at least two connections for connecting the casing to the heating circuit of the heat pump. A first connection forms a fluid inlet and a second connection forms a fluid outlet for a heating fluid, in particular heating water. The casing is formed in one piece and has a transition contour between the base and the fluid outlet, which tapers continuously from the base of the casing to the fluid outlet to generate a homogeneous fluid flow within the casing.

[0007] The one-piece construction of the housing eliminates the need for soldered connections between the fluid outlet and the housing body, thus avoiding sharp-edged flow geometries. The transition contour, designed to create a homogeneous fluid flow between the housing body and the fluid outlet, ensures the proper functioning of downstream components such as flow sensors. Furthermore, a homogeneous flow prevents malfunctions and, in particular, partial overheating of the heating element, which can lead to its destruction. The uniform supply of heating water to the heating element also achieves maximum power transfer. With demand-based power transfer in conjunction with a controllable, high-efficiency pump, only the electrical energy required for the respective operating point is consumed.This results in cost-effective operation of the heat pump and a long service life for the heating system. The one-piece design of the housing not only allows for an optimal transition contour to generate a homogeneous fluid flow, but also offers significant advantages in terms of sealing and manufacturing costs.

[0008] A heat pump according to the invention is particularly advantageous in which the transition contour is adapted to the geometry and position of the at least one heating element, as well as to the number of heating elements. The outlet geometry, i.e., the transition contour, is designed such that a nearly homogeneous flow results at the outlet of the heating fluid from the housing, the shape and characteristics of which can vary depending on the heating elements used. It is particularly advantageous if the transition contour is designed as a body of revolution, which is preferably symmetrical with respect to a longitudinal axis of the housing's base body. The transition contour, and in particular the body of revolution, is preferably essentially conical or bell-shaped. In other words, the transition contour tapers continuously from the housing's base body towards the fluid outlet of the housing.Radii, chamfers, and / or bevels can be used to create the transition contour between the base body and the fluid outlet, defining the transition contour inside the housing. The number and shape of these radii, chamfers, and / or bevels can be optimally adapted to the specific heating elements used. To this end, the optimal transition contour between the base body and the fluid outlet can be simulated using a suitable simulation program before the housing is manufactured.

[0009] The fluid inlet and outlet are preferably designed as extensions for connecting heating circuit lines. Their external geometry is therefore preferably adapted to the lines to be connected. The fluid inlet is preferably located on the circumferential surface of the essentially cylindrical base body. However, it is also possible for the fluid inlet to be located in a cover that closes the housing. Furthermore, it is not excluded that additional connections may be provided on the housing. These additional connections, which are in particular fluid inlets, may be located either in the cover or on the circumferential surface of the base body. For example, more fluid inlets may be necessary if a bypass line is to be connected to the housing or if several return lines lead back from the heating system. The bypass line could, for example, be a...This could also be a return line from a storage water heater. The fluid outlet, however, is preferably located on an end face of the housing that, when the housing is installed, points downwards. Opposite the end face with the fluid outlet, an opening is preferably provided in the housing through which the at least one heating element can be inserted. The opening is preferably closable with a cover. The housing preferably has locking elements for the cover to form a quick-release fastener, with the locking elements preferably being integrally formed with the housing. It is particularly advantageous if the quick-release fastener is designed as a bayonet fitting.

[0010] The housing can be made of plastic, for example. Injection molding or other plastic processing methods are particularly suitable for this purpose. This allows the housing to be easily adapted to an optimal, predetermined transition contour in the area between the base body and the fluid outlet, and it is also cost-effective to manufacture and readily adaptable to various heating element designs. The heating element(s) can, for example, be spiral-shaped. Alternatively, the housing can be manufactured as a casting, for example, using a suitable casting process such as brass casting or aluminum die casting.In this case, too, the housing is manufactured not only in an optimally adapted manner to the type and number of heating elements, avoiding sharp-edged outflow geometries, but also cost-effectively, thus avoiding complex assembly using soldering and welding processes. The housing is adapted to the shape of the heating element(s) in such a way that the longitudinal axis of the essentially cylindrical housing preferably coincides with the longitudinal axis of the (spiral-shaped) heating element.

[0011] Furthermore, the improved accessibility of such a housing should be noted. The heat pump's cover can be easily removed from the housing, particularly by means of a quick-release fastener, so that the heating element can be removed from the housing at any time for cleaning, maintenance, or repair purposes. The quick-release fastener is preferably designed as a bayonet fitting with corresponding locking elements. The locking elements are preferably integrally connected to the housing and thus preferably made of the same material as the housing. The heating elements are preferably connected to the cover. In particular, the connections, especially the electrical connections, of the at least one heating element can be designed as plug connectors that extend through the cover.On the side of the lid opposite the heating element, a suitable heating control device can then be directly connected to the lid and to the connections of the heating element.

[0012] Overall, the heating element can be installed quickly and easily into the housing and securely fixed using a quick-release fastener. The absence of welding between the cover and the housing ensures easy access to the heating element. The heat pump is a compact unit that can be manufactured quickly and cost-effectively with minimal effort.

[0013] The invention will be explained in more detail below with reference to the drawing.

[0014] They show: Fig. 1 a schematic cross-sectional view of a housing system according to the invention; Fig. 2 a schematic representation of the flow conditions in the area of ​​the transition contour of a housing according to the invention, and Fig. 3 a top view of the lid of a housing system according to the invention.

[0015] The Fig. Figure 1 shows a housing system 1 with a housing 3 and a cover 5, which closes an opening in the housing 3. In the present embodiment, the housing system further comprises three heating elements 7, 7' and 7", each spirally shaped, with at least two of the heating elements arranged concentrically to each other in certain areas. The heating elements can be inserted into the housing 3 through the opening, which can be closed by the cover 5. It is understood that the number, arrangement and design of the heating elements are chosen here purely as examples.

[0016] The housing 3 comprises two connections for integrating it into the heating circuit of a heat pump. A first connection, which in this embodiment is arranged on a substantially cylindrical base body 9 of the housing 3, forms a fluid inlet 11, while a second connection forms a fluid outlet 13. To ensure that the heating fluid flows around the heating elements over as large an area as possible, the fluid inlet 11 is preferably located near the opening of the housing, i.e., in the upper part of the housing 3. The fluid outlet 13, on the other hand, is located on an end face 15 in the lower part of the housing 3, which faces the ground when the housing system 1 is installed. Both the fluid inlet 11 and the fluid outlet 13 are designed as extensions and have an outer contour that is substantially cylindrical and adapted for connection to a corresponding pipe of the heating circuit.The fluid inlet 11 does not necessarily have to be connected to the base body 9 of the housing 3. Rather, it is also conceivable to form the fluid inlet 11 in the cover 5, so that the base body 9 has a substantially continuous cylindrical outer contour. The base body 9, the fluid inlet 11, and the fluid outlet 13 are formed as a single piece.

[0017] The cover 5 is connected to the housing 3 via an O-ring seal 17. The heating elements 7, 7' and 7" are arranged inside the housing 3 and extend in a direction that coincides with the longitudinal axis L of the housing 3. The heating elements are connected to the cover 5 such that the (electrical) connections 19 of the heating elements, which are designed as plug connectors, extend through the cover 5 in corresponding recesses. In this way, the heating elements can be easily connected to a power source or to a heating control system (in the Fig. 1 not shown).

[0018] A transition contour 21 is arranged between the base body 9 and the fluid outlet 13 of the housing 3. This transition contour is designed to generate a homogeneous flow of the heating fluid within the housing 3. The transition contour 21 is integrally connected to the base body 9 and the fluid outlet 13. The transition contour is preferably individually adapted to the number, geometry, and position of the heating elements in the housing 3. It is preferably rotationally symmetrical with respect to the longitudinal axis L of the housing 3 and consequently forms a body of revolution that tapers from the base body 9 towards the fluid outlet 13. This results in a substantially conical or bell-shaped contour for the transition area between the base body 9 and the fluid outlet 13, which constitutes the transition contour.An optimal transition contour can be determined prior to the housing's manufacture by simulating the flow conditions when using one or more specific heating elements. Crucially, the transition area between the base body 9 and the fluid outlet 13 must not have a sharp outflow geometry, but rather a smooth, flowing, or rounded transition between the base body and the fluid outlet, ensuring a homogeneous flow. To achieve the optimal transition contour, the transition area between the base body and the fluid outlet can be provided with a specific radius or radii, as well as chamfers and / or bevels.

[0019] The Fig. Figure 2 shows a schematic flow path 23 of a heating fluid, which originates from the fluid inlet 11 (in the Fig. (2 not shown) flows to the fluid outlet 13 along the transition contour 21, thereby flowing around the heating elements 7. Fig. Figure 2 makes it clear that the tapered design of the transition contour 21 between the base body 9 and the fluid outlet 13 results in a homogeneous flow pattern 23, which generates a uniform flow around the heating elements and a turbulence-free discharge of the heating fluid without turbulence.

[0020] The one-piece design of the housing 3, and thus the one-piece design of the base body 9, the transition contour 21, and the fluid outlet 13, allows for simple manufacturing of the transition contour and adaptation to various heating element geometries. For example, if the housing 3 is made of plastic, such as by injection molding, a corresponding injection mold can be individually adapted to any heating element.

[0021] The Fig.Figure 3 shows a top view of the cover 5 of the housing 3, from which the connections 19 of the heating elements 7 protrude. A quick-release fastener 25 is preferably provided for attaching the cover 5 to the housing 3; in this embodiment, it is designed as a bayonet fitting. For this purpose, the cover 5 comprises a total of four recesses 27 in the edge region, which interact with projections 29 provided on the housing 3 and, in particular, formed integrally with it. The projections are designed as locking elements that allow the cover 5 to rotate such that the locking elements 29 engage with the top surface of the cover 5. This is therefore a rotary lock that allows the cover 5 to be opened at any time. In this way, quick access to the interior of the housing 3 is ensured, for example, for maintenance or cleaning purposes.Furthermore, a heating control unit and / or an energy source can be provided directly on the lid.

[0022] Overall, the present invention provides a housing 3 and a corresponding housing system 1 which is easy and inexpensive to manufacture, which also provides optimal flow conditions at the fluid outlet, and which ensures easy access for cleaning, maintenance and repair purposes. Reference symbol list 1 Housing system 3 cases 5 lids 7, 7', 7" heating elements 9 basic shapes 11 Fluid inlet 13 Fluid outlet 15 Front 17 Seal 19 connections 21 Transition contour 23 Flow pattern 25 quick-release fasteners 27 recess 29 Locking element L Longitudinal axis

Claims

[1] Heat pump with a heating circuit, in particular for hot water preparation, wherein at least one heating element (7), in particular at least one electric heating element, is installed in the heating circuit, which is housed in a casing (3), wherein the casing (3) has a cylindrical base body (9) and at least two connections for connecting the casing to the heating circuit of the heat pump, wherein a first connection forms a fluid inlet (11) and a second connection forms a fluid outlet (13) for a heating fluid, in particular heating water, characterized by , that the housing (3) is formed in one piece and has a transition contour (21) between the base body (9) and the fluid outlet (13) which tapers continuously from the base body (9) of the housing (3) to the fluid outlet (13) of the housing (3) to generate a homogeneous fluid flow in the housing (3). [2] Heat pump according to claim 1, characterized by, that the transition contour (21) is designed as a body of revolution, which is in particular symmetrical with respect to a longitudinal axis (L) of the base body (9) of the housing (3). [3] Heat pump according to claim 1 or 2, characterized by , that the transition contour (21) is essentially conical or bell-shaped. [4] Heat pump according to any one of the preceding claims, characterized by , that the transition contour (21) has radii, chamfers and / or bevels between the cylindrical base body (9) and the fluid outlet (13). [5] Heat pump according to any one of the preceding claims, characterized by , that the fluid inlet (11) and the fluid outlet (13) are designed as extensions for connecting lines of the heating circuit. [6] Heat pump according to any one of the preceding claims, characterized by , that the fluid inlet (11) is arranged on the circumferential surface of the base body (9). [7] Heat pump according to any one of the preceding claims, characterized by , that the fluid outlet (13) is located in the area of ​​an end face (15) of the housing (3). [8] Heat pump according to any one of the preceding claims, characterized by , that the housing (3) has an opening on the end face opposite the fluid inlet (11) through which the at least one heating element (7) can be inserted into the housing (3). [9] Heat pump according to claim 8, characterized by , that the opening can be closed with a lid (5). [10] Heat pump according to any one of the preceding claims, characterized by , that the housing (3) is made of plastic, in particular by injection molding. [11] Heat pump according to any one of the preceding claims, characterized by , that the housing (3) is manufactured as a casting, in particular in a metal casting process. [12] Heat pump according to any one of the preceding claims, characterized by, that the at least one heating element (7) is spirally shaped. [13] Heat pump according to any one of the preceding claims, characterized by , that several fluid inlets (11) are arranged on the circumferential surface of the base body (9). [14] Heat pump according to claim 9, characterized by , that at least one heating element (7) is connected to the lid (5). [15] Heat pump according to claim 9 or 14, characterized by , that the at least one heating element (7) has in particular electrical connections (19) which are preferably designed as plug connections which extend through the cover (5). [16] Heat pump according to one of claims 9, 14 or 15, characterized by , that the lid (5) and the housing (3) can be connected to each other by means of a quick-release fastener (25), in particular by means of a bayonet fastener. [17] Heat pump according to claim 16, characterized by, that locking elements (29) of the quick-release fastener (25), in particular the bayonet fastener, are formed integrally with the housing (3). [18] Heat pump according to one of claims 9 or 14 to 17, characterized by , that the lid (5) is directly connected to a heating control device. [19] Heat pump according to one of claims 9 or 14 to 18, characterized by , that at least one fluid inlet (11) is arranged in the lid (5). [20] Heat pump according to one of claims 9 or 14 to 19, characterized by , that at least one fluid inlet (11) is arranged on the circumferential surface of the base body (9) and at least one further fluid inlet is arranged in the lid (5).

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