EP3945268A1 - Heat pump system - Google Patents

Abstract

The present invention relates to a heat pump system in which an evaporator, a compressor, at least one buffer storage tank with a condenser coil device arranged therein for conducting refrigerant and an expansion valve are arranged in succession in a closed circuit, with a stainless steel coil surrounded radially by the condenser coil device for Passing through drinking water is arranged; and at least one cold service water inlet, a cold drinking water inlet connected to the stainless steel coil, an outlet for underfloor heating fluid, an outlet for radiator heating fluid and a hot drinking water outlet are arranged on the buffer storage tank. It is the object of the present invention to reduce pressure losses in the generic heat pump system and thereby achieve better heat transfer. This object is achieved by a heat pump system in which the condenser coil device has an outer condenser coil and an inner condenser coil running between the outer condenser coil and the stainless steel coil.

Description

The present invention relates to a heat pump system in which an evaporator, a compressor, at least one buffer storage tank with a condenser coil device arranged therein for conducting refrigerant and an expansion valve are arranged in succession in a closed circuit, with a stainless steel coil surrounded radially by the condenser coil device for Passing through drinking water is arranged; and at least one cold service water inlet, a cold drinking water inlet connected to the stainless steel coil, an outlet for underfloor heating fluid, an outlet for radiator heating fluid and a hot drinking water outlet are arranged on the buffer storage tank.

A conventional heat pump system typically consists of an evaporator in which a refrigerant is evaporated, thereby extracting heat from the surrounding medium. The refrigerant is compressed into hot gas by a compressor and liquefied in a condenser. In the process, heat is given off again to the surrounding medium. An expansion valve injects the refrigerant back into the evaporator under reduced pressure. There the physical state changes again from liquid to gaseous and the refrigerant absorbs heat again. A buffer store, which can absorb a high heat capacity, is connected to the condenser via heat pipes, with the heat being transported by a pump from the condenser to the buffer store. Due to the low achievable temperature level in the buffer tank, only low-temperature heating systems can be fed by a heat pump system according to this embodiment.

In a further known embodiment variant, the structure of the above-mentioned system is supplemented by a hot gas lance, through which a small quantity of hot gas is fed into the upper part of the buffer store via an additional ring line. The flow temperature of the buffer storage tank increases in this layer, which means that the storage water located there can be used advantageously for heating water, for example.

A further increase in efficiency can be achieved by integrating the condenser directly into the buffer tank. An example of such an arrangement is provided by the reference DE 10 2005 011 709 A1 known. Here, the condenser is arranged in the form of a coil in a service water storage tank, to which cold water can be supplied via a line. Hot water can be tapped from the service water storage tank via another line. Furthermore, an electric auxiliary heater is provided within the coil of the condenser, which is intended to heat up the cold water flowing into the service water storage tank more quickly. In addition to increased acquisition costs, this leads to an additional increase in the operating costs during the period of use of the heat pump device and to a relatively complex device arrangement.

A heat pump system of the type specified above is from the utility model DE 20 2009 008 405 U1 known. In this heat pump system, a separating means between an upper coil unit and a lower coil unit of the condenser is provided in the buffer tank above a central plane of the buffer tank, the upper coil unit being connected to the lower coil unit by a tubular arrangement, so that the coil units are separated from the top to bottom by the Refrigerant can flow through. Since the upper spiral unit carries hot gas and can therefore transfer the greatest amount of energy to the liquid in the buffer storage tank, the separating means provided between the upper and lower spiral units create an area within the buffer storage tank with a very high temperature at the top and an area at the bottom with a lower but still high temperature. The separating means thereby minimizes an undesired mixing of the storage liquid between the two areas in a particularly effective manner.

However, pressure losses have arisen in this heat pump system, which have led to a reduction in the efficiency of the heat pump system.

It is therefore the object of the present invention to reduce pressure losses in the generic heat pump system and thereby achieve better heat transfer.

This object is achieved by a heat pump system in which, in a closed circuit, an evaporator, a compressor and at least one buffer storage tank are installed one after the other with a condenser coil device arranged therein for the passage of refrigerant and an expansion valve being arranged, wherein a stainless steel coil surrounded radially by the condenser coil device for passage of drinking water is arranged in the buffer store; and at least one cold service water inlet, a cold drinking water inlet connected to the stainless steel coil, an outlet for floor heating heating fluid, an outlet for radiator heating fluid and a hot drinking water outlet are arranged on the buffer storage tank, and wherein the condenser coil device has an outer condenser coil preferably arranged on an inner circumference of the buffer storage tank and one between the outer condenser coil and the inner condenser coil has running stainless steel coil.

In the present invention, the terms "above", "upper", "lower", "above" and "below" are to be understood as they would appear to an observer in the case of an upright buffer storage tank during operation of the heat pump system according to the invention, as in figure 1 shown schematically result. The same applies to all further versions of the present description.

The pressurized, hot refrigerant can be divided between the two strands of the condenser coil device, as a result of which the pressure losses are reduced. In addition, the two condenser coils have a larger surface area in contact with the storage liquid of the buffer store than one, so that there is improved heat transfer. The heat pump system according to the invention thus has increased efficiency.

In an advantageous embodiment of the heat pump system according to the invention, the total length of the outer condenser coil is equal to the total length of the inner condenser coil. As a result, each of the lines has the same pressure loss, so that the lines can be brought together again optimally after passing through the buffer storage.

The outer condenser coil preferably has an upper, outer condenser coil and a lower, outer condenser coil connected thereto, between which a horizontal separating means is arranged; and the inner condenser coil has an upper, inner condenser coil and a lower, inner condenser coil connected thereto, between which the horizontal separating means is arranged, wherein the stainless steel coil extends continuously from an area below the horizontal parting means to an area above the horizontal parting means.

In a further advantageous embodiment of the present invention, the heat pump system has an insulation ring guided around a number of coils of the condenser coil device in the buffer store and forming a heat buffer area around these coils, with a fluid inlet being arranged at the bottom of the heat buffer area and a fluid outlet at the top of the heat buffer area. A warm fluid can thus be generated in a section of the buffer store, buffered and discharged directly from this area to the outside for further use, for example as a fluid for operating underfloor heating.

For this procedure, it is not necessary to provide the coils of the condenser coil device with a sheathing in this area, which would not be installable at all for reasons of space, particularly in the case of coils of the condenser coil device running close to one another. Instead, the insulating ring forms a kind of basket or vessel around the number of coils of the condenser coil device, in which the fluid remains for a definable time so that it can be heated in a targeted manner.

This can preferably be technically implemented in that an outer jacket of the insulation ring is formed by a section of an inner circumference of the service water storage tank and an inner jacket of the insulation ring runs around the stainless steel coil, with the heat buffer area being formed between the outer jacket and the inner jacket and the fluid inlet and fluid outlet passing through guide the outer sheath.

The outer jacket of the insulation ring is therefore particularly preferably formed by a section of the inner circumference of the service water storage tank and the inner jacket of the insulation ring is guided around the stainless steel coil, with a number of coils of the outer condenser coil and the inner condenser coil being arranged in the heat buffer area between the outer jacket and the inner jacket and wherein a fluid inlet leading through the outer jacket is arranged at the bottom of the heat buffer area and a fluid outlet leading through the outer jacket is arranged at the top of the heat buffer area.

It is particularly advantageous if, according to one embodiment of the present invention, the insulating ring is arranged below the horizontal separating means. This creates the possibility of also being able to effectively use the heat from the condenser coil device, which has already cooled down somewhat in the lower part of the buffer store.

A particularly effective production of hot drinking water is achieved if, in one embodiment of the heat pump system according to the invention, the stainless steel coil extends vertically through the entire buffer storage tank. In this embodiment, the high-grade steel coil is guided into the buffer tank at the very bottom, while hot drinking water is removed from the high-grade steel coil at the top of the buffer tank. As a result, the drinking water, which is carried in the stainless steel coil, can be preheated in the buffer storage tank below and subsequently heats up more quickly. At the bottom of the buffer tank, the temperature of the drinking water is, for example, around 8 to 10 °C, in the middle of the buffer tank around 30 °C and can be increased to around 50 °C at the top of the buffer tank, if required.

A preferred embodiment of the present invention, its structure, function and advantages is described below with reference to figure 1 described, in which a heat pump system 1 according to the present invention is shown schematically in a sectional side view.

The heat pump system 1 has a single, closed refrigerant circuit, which in use of the heat pump system 1 of a refrigerant 6, such as a hydrofluorocarbon or mixture, propane, propene, a propane-butane mixture, ammonia or carbon dioxide, in a with the arrows marked direction of flow.

The heat pump system 1 has an evaporator 2 which is designed as a heat exchanger and in which the refrigerant 6 is evaporated. The refrigerant 6 extracts heat from the surrounding medium. The evaporator 2 is connected to a compressor 3 via a line. The compressor 3 compresses the vaporized refrigerant 6 into the so-called hot gas. The compressor 3 is in turn connected via a line to a condenser, which according to the invention is designed as a condenser coil device 5 . The condenser coil device 5 is in the arrangement according to the invention provided within a buffer memory 4 forms and with this a structural unit.

The condenser coil device 5 is a heat exchanger in which the refrigerant 6 is condensed or liquefied, with heat being released from the refrigerant 6 to the storage liquid 24 which is provided in the buffer store 4 and surrounds the condenser coil device 5 and which is typically water. According to the invention, the condenser coil device 5 is not a separate heat exchanger but is embodied in a helical shape in the buffer store 4 .

like it in figure 1 As can be seen, the coolant 6 flows through the condenser coil device 5 in the buffer store 4 using the preferred flow direction of the coolant 14 caused by gravity from top to bottom. Due to the helical shape of the liquefier coil device 5, the refrigerant 6 covers a long distance in the liquefier coil device 5 and thus also in the buffer store 4 and can therefore transfer a particularly large amount of energy to the surrounding medium, i.e. in the example of figure 1 to the storage liquid 24. The surrounding medium flows very slowly or is completely at rest.

The condenser coil device 5 is connected to an expansion valve 7 via a line. The expansion valve 7 injects the refrigerant 6 at reduced pressure into the evaporator 2, to which the expansion valve 7 is connected via a pipe, whereupon the circulation of the refrigerant 14 described above is restarted.

In other embodiments of the invention that are not shown here, the heat pump system 1 can have an intermediate heat exchanger, such as that described in the publication DE 20 2009 008 405 U1 is shown, which is provided on the one hand between the exit from the condenser coil device 5 and the entry into the expansion valve 7 and on the other hand between the exit from the evaporator 2 and the entry into the compressor 3 . With such an intermediate heat exchanger, residual heat contained in the refrigerant 6 coming from the condenser coil device 5 arranged in the buffer store 4 can be used to increase the temperature of the refrigerant 14 or hot gas flowing into the compressor 3 and thereby increase the overall efficiency of the heat pump system 1 to put.

Buffer memory 4 is in the example of FIG figure 1 a container that is upright during operation, cylindrical or cuboid or approximately oval in cross section, but can also be a container with another suitable geometry that allows a storage liquid 24 to be received and removed from the buffer store 4 .

Above a central plane of the buffer store 4, horizontal separating means 13 is provided in the latter, which separates an upper coil area of the condenser coil device 5 from a lower coil area of the condenser coil device 5, the upper coil area being connected to the lower coil area by, in the example shown, tubular connecting means 513, 523 is connected to each other.

The tubular connecting means 513, 523 are arranged on a side edge of the buffer store 4 in the embodiment variant shown, but can also be provided in the middle, passing through the separating means 13, in other exemplary embodiments of the invention that are not shown. The arrangement and the height of the tubular connecting means 513, 523, which are not coiled in the example shown, depend on the arrangement and the thickness of the separating means 13.

in the in figure 1 illustrated embodiment, the separating means 13 is designed as a horizontal, planar separating plate having no interruptions. In other embodiment variants of the present invention, not shown, other suitable, horizontal separating means 13, such as made of other materials, such as plastic or a suitable thermal insulation material, and/or also in a wavy or profiled form within the buffer storage 4 can be used. The separating means 13 can also be bent or angled. Furthermore, it can also lie slightly at an angle in the buffer store 4 . Likewise, the separating means 13 may not be continuous, but may also be discontinuous and may, for example, have holes or slits, which may be used, for example, for connecting means 513, 523 to pass through.

The separating means 13 preferably extends over at least 50% of the internal cross section of the buffer reservoir 4 accommodating the storage liquid 24, but allows an unimpeded passage of the non-coiled, tubular connecting means 513, 523 and a certain transfer of storage liquid 24 between the areas formed above and below the separating means 13, but prevents spontaneous mixing between these areas. Correspondingly, a particularly suitable heat stratification is formed in the buffer tank 4, with the upper coil area having particularly high temperatures and the areas below the separating means 13 also having higher temperatures than cold tap water, but lower than in the area above the separating means 13 are.

This is achieved in particular by the fact that the refrigerant 6 is still present as hot gas in the upper coil area of the condenser coil device 5 and is therefore able to release a particularly large amount of thermal energy to the surrounding medium, i.e. to the storage liquid 24 surrounding the upper coil area, while only a change in the state of aggregation of the refrigerant 14 from gaseous to liquid takes place in an area of change of aggregation in the lower coil area, as a result of which the refrigerant 6 can emit less energy there and the storage liquid 24 accordingly has lower temperatures.

The condenser coil device 5 has an outer condenser coil 51 , which is preferably arranged on an inner circumference 40 of the buffer store 4 , and an inner condenser coil 52 running between the outer condenser coil 51 and the stainless steel coil 8 . The outer condenser coil 51 thus has a larger diameter than the inner condenser coil 52 in a sectional plan view of the buffer store 4.

In the exemplary embodiment shown, however, it is nevertheless the case that the respective overall length of the outer condenser coil 51 is the same as that of the inner condenser coil 52 . This is realized here in that the inner condenser coil 52 extends further down than the outer condenser coil 51 .

The outer condenser coil 51 has an upper, outer condenser coil 511 formed above the separating means 13 and a lower, outer condenser coil 512 which is connected thereto by means of the connecting means 513 and is arranged below the separating means 13 . The inner condenser coil 52 has an upper, inner condenser coil 521 and a lower, inner condenser coil 522, which is connected to it by means of the connecting means 523 and is arranged below the separating means 13.

In a sectional plan view of the buffer store 4, the upper, outer condenser coil 511 and the lower, outer condenser coil 512 lie one above the other in an annular outer coil region of the buffer store 4, the upper, inner condenser coil 521 and the lower, inner condenser coil 522 lie one above the other in an annular inner coil region of the buffer store 4, the inner radius of the outer helix area being larger than the outer radius of the inner helix area.

The upper coil area as well as the lower coil area, i.e. the upper, outer condenser coil 511 and the upper, inner condenser coil 521 surrounded by it, as well as the lower, outer condenser coil 512 and the lower, inner condenser coil 522 surrounded by it, coil around one from below at the top, that is to say vertically through the interior of the buffer store 4, stainless steel coil 8. This means that the stainless steel coil 8 runs almost continuously through the entire buffer store 4, through the horizontal separating means 13. The stainless steel coil 8 is thus surrounded by the warm coils of the liquefier coil device 5 and the storage liquid 24 in the buffer store 4 that has been heated up by this.

The stainless steel coil 8 preferably has a smaller diameter than the coils of the condenser coil device 5 . Drinking water 9 is conducted in the stainless steel coil 8, which is introduced cold into the stainless steel coil 8 through an inlet 42 and is removed from it as hot water 9b at a removal device 44.

The lower coil area of the heat pump system 1 can, as in the publication DE 20 2009 008 405 U1 as described, may be encased in a portion by a shroud, such as a tube, through which a fluid may be passed. The sheathing can be of any length at any point in the lower coil area. The fluid circulating in the casing can be removed at a removal device, which is preferably provided on the buffer store 4 in a central third of the buffer store 4, for transfer and use in a coupled circuit.

This fluid is preferably pumped through the casing in the lower coil region of the condenser coil device 5 with the aid of a pumping device counter to a flow direction of the refrigerant 14 . As a result, the fluid can absorb heat from the refrigerant 6 particularly effectively. For example, this makes the fluid particularly well suited as a radiator fluid.

In the embodiment of figure 1 however, no casing is provided on the condenser coil device 5 for reasons of space. Instead, an insulating ring 14 is arranged in a section of the lower coil region of the condenser coil device 5, ie around the lower, outer condenser coil 512 and at the same time around the lower, inner condenser coil 522 surrounded by it. In the exemplary embodiment shown, the outer jacket of the insulating ring 14 is formed by a section of the inner circumference 40 of the service water storage tank 4 . The inner jacket 142 of the insulation ring 14 leads around the stainless steel coil 8. A number of coils of the lower, outer condenser coil 512 and the lower, inner condenser coil 522 are arranged in a heat buffer region 140 of the insulation ring 14 located between the outer jacket 141 and the inner jacket 142. At the bottom of the heat buffer area 140 there is a fluid inlet 46 leading through the outer jacket 141 for a fluid 11a and at the top of the heat buffer area 140 there is a fluid outlet 47 leading through the outer jacket 141 for the heated fluid 11b.

However, in another variant of the invention, not shown here, a cladding can also be provided in this area. This area is also used to heat the storage liquid 24 in the buffer store 4, which can be removed from the buffer store 4 via a removal device. The last section after the lowest coil of the lower condenser coil in the buffer store 4 is designed as a non-coiled tube and directs the refrigerant 6 from the buffer store 4 back into the circuit of the heat pump system 1 described above.

The heat pump system 1 has a jacket 26 which is approximately oval in shape and is provided with foam in its interior for heat insulation and noise insulation. In the exemplary embodiment shown, the thickness of the foam is about 10 cm, but it can also have a different thickness in other exemplary embodiments of the present invention that are not shown.

The jacket 26 surrounds a steel housing of the buffer store 4. Inside the buffer store 4 is the storage liquid 24, the upper and lower condenser coils of the condenser coil device 5 described in detail above, and the stainless steel coil 8 arranged within the upper condenser coil for generating hot water.

The jacket 26 also surrounds the compressor 3 and the evaporator 2, which are connected to one another and to the condenser coils via lines. At the in figure 1 shown embodiment of the heat pump system 1, the evaporator 2 and the compressor 3 are integrated in one and the same housing formed by the jacket 26 in the buffer storage tank 4. There is air around the evaporator 2 and the compressor 3 .

In addition, a control and/or regulation unit 29 for the heat pump system 1 is provided on one side of the casing 26 . in the in figure 1 shown embodiment, the control and / or regulation unit 29 is integrated in a sheet metal part. The temperatures and the temperature distribution in the buffer store 4 can be regulated with the aid of the control and/or regulation unit 29 . In addition, the water supply as well as the water withdrawal in and from the buffer storage 4 can be regulated. For this purpose, the control and/or regulation unit 29 is coupled to various sensors, such as temperature sensors, provided in or on the heat pump system 1 . The control and/or regulation unit 29 can also have a display unit, through which a user of the heat pump system 1 according to the invention can check various parameters, such as the different temperatures at the inputs and outputs of the buffer store 2 .

Claims (7)

Heat pump system (1), in which an evaporator (2), a compressor (3), at least one buffer store (4) with a condenser coil device (5) arranged therein for the passage of refrigerant (6) and an expansion valve (7 ) are arranged, wherein a stainless steel coil (8) radially surrounded by the condenser coil device (5) is arranged in the buffer store (4) for the passage of drinking water (9); and on the buffer storage (4) at least one cold service water inlet (41), one with the stainless steel coil (8) connected cold drinking water inlet (42), an outlet (43) for underfloor heating fluid (11b), an outlet (44) for radiator heating fluid (12) and a Hot drinking water outlet (45) are arranged;
characterized,
that the condenser coil device (5) has an outer condenser coil (51) and an inner condenser coil (52) running between the outer condenser coil (51) and the stainless steel coil (8). Heat pump system according to Claim 1, characterized in that the overall length of the outer condenser coil (51) is equal to the overall length of the inner condenser coil (52). Heat pump system according to Claim 1 or 2, characterized in that the outer condenser coil (51) has an upper, outer condenser coil (511) and a lower, outer condenser coil (512) connected thereto, between which a horizontal separating means (13) is arranged; and the inner condenser coil (52) has an upper, inner condenser coil (521) and a lower, inner condenser coil (522) connected thereto, between which the horizontal separating means (13) is arranged, the stainless steel coil (8) extending continuously from one area extends below the horizontal separating means (13) into a region above the horizontal separating means (13). Heat pump system according to one of the preceding claims, characterized in that the heat pump system (1) has an insulating ring (14) guided around a number of coils of the condenser coil device (5) in the buffer store (4) and forming a heat buffer area (140) around these coils, a fluid inlet (46) being arranged at the bottom of the heat buffer area (140) and a fluid outlet (47) at the top of the heat buffer area (140). Heat pump system according to Claim 4, characterized in that an outer casing (141) of the insulating ring (14) is formed by a section of an inner circumference (40) of the service water storage tank (4) and an inner casing (142) of the insulating ring (14) around the stainless steel coil (8 ) leads, wherein the heat buffer area (140) between the outer shell (141) and the inner shell (142) is formed and the fluid inlet (46) and the fluid outlet (47) lead through the outer shell (141). Heat pump system according to Claim 4 or 5, characterized in that the insulating ring (14) is arranged below the horizontal separating means (13). Heat pump system according to one of the preceding claims, characterized in that the stainless steel coil (8) extends vertically through the entire buffer store (4).

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