US20140216077A1

US20140216077A1 - Apparatuses and methods for use of a pump with a heatable pump chamber in a heat-pump apparatus and for operating the heat-pump apparatus

Info

Publication number: US20140216077A1
Application number: US14/172,482
Authority: US
Inventors: Tobias Albert; Stefanie Roth; Uwe Koegel
Original assignee: EGO Elektro Geratebau GmbH
Current assignee: EGO Elektro Geratebau GmbH
Priority date: 2013-02-06
Filing date: 2014-02-04
Publication date: 2014-08-07
Also published as: DE102013201903A1; EP2765360A2; EP2765360A3

Abstract

A heat-pump apparatus for heating purposes has a collector circuit for a heat source with a collector pump for a collector fluid, also has a refrigerant circuit with an evaporator and a condenser for a refrigerant in the refrigerant circuit and with a compressor and a pressure-relief valve, and additionally has a heating circuit with a heating pump for a heating fluid, with heating means for heating purposes. At least the collector pump and/or the heating pump are/is designed in the form of a pump with a heatable pump chamber for heating the fluid delivered by the pump.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to German Application No. 10 2013 201 903.3, filed Feb. 6, 2013, the contents of which are hereby incorporated by reference in their entirety.

TECHNOLOGICAL FIELD

The invention relates to a heat-pump apparatus for heating purposes, in particular for heating buildings and/or rooms, to a use of a pump with a heatable pump chamber in a heat-pump apparatus, and to a method of operating a heat-pump apparatus for heating purposes having an aforementioned pump.

BACKGROUND

Heat-pump apparatuses have been known in general for some time now, see, for example, DE 202009008908 U1 or DE 102010035327 A1. Such a heat-pump apparatus may have a collector circuit, a refrigerant circuit and a heating circuit. A collector pump may be provided in a collector circuit and a heating pump may be provided in the heating circuit. By means of these pumps, in the respective circuits, a fluid which absorbs and transports, and/or also dissipates, the heat can be pumped or circulated in order, ultimately, to bring heat from a heat source, such as the ground, water or air, into the heating circuit and make it available for heating purposes. This operation, of extracting heat from the surroundings and raising it to a higher level in order then to be able to use it for heating purposes is based on the Joule-Thomson effect. A heat-pump apparatus does indeed require electrical energy, in particular for the pumps and for a compressor in the refrigerant circuit. The overall energy yield for heating purposes, however, is considerably greater, and therefore it is precisely in respect of increasing the proportion of energy from renewables and of reducing the energy consumption overall that there is an ever-increasing demand for such heat-pump apparatuses.
Furthermore, EP 2348944 A1 discloses a pump which has a heater integrated in it. This allows a more efficient use in domestic appliances such as dishwashers or washing machines.

BRIEF SUMMARY

The invention is based on the problem of creating a heat-pump apparatus, as mentioned in the introduction, a use and a corresponding method which make it possible to avoid problems of the prior art and, in particular, to use a heat-pump apparatus for heating purposes in a more energy-efficient and/or flexible manner.
This problem is solved by a heat-pump apparatus, by a use and by a method. Advantageous and preferred configurations of the invention form the subject matter of the claims and will be explained in more detail hereinbelow. Some of the features here are mentioned only in respect of the heat-pump apparatus, only in respect of the use or only in respect of the method. Irrespective of this, however, they should be allowed to apply not only to the heat-pump apparatus but also to the use and to the method. The wording of the claims makes express reference to the contents of the description.
It is provided that the heat-pump apparatus has a collector circuit, in which a collector fluid is circulated or circulates. The heat source used may be, as mentioned above, soil, water or air. Also provided is a refrigerant circuit, with a refrigerant, and an evaporator and a condenser therefor and a compressor and a pressure-relief valve therein. Finally, a heating circuit is also provided, with a heating fluid therein and with heating means, which are usually radiators and/or underfloor heaters, through which the hot heating fluid flows. Also provided here is a heating pump for circulating the heating fluid.
In a known manner, the collector circuit interacts with the evaporator of the refrigerant circuit, and therefore heat is dissipated from the collector fluid to the refrigerant, wherein preferably the collector fluid has approximately the temperature of the heat source, the collector fluid being compressed by the compressor. The condenser of the refrigerant circuit interacts with the heating circuit in order to dissipate heat from the refrigerant to the heating fluid. Once heat has been dissipated from the refrigerant to the heating fluid, it is relieved of pressure again by means of the pressure-relief valve and evaporates again in the evaporator.
According to the invention, it is provided that at least one of the pumps in the collector circuit or in the heating circuit, that is to say the collector pump and/or the heating pump, is designed in the form of a pump with a heatable pump chamber, in order thus to heat the fluid delivered by the pump. The pump chamber here is that region of the pump in which a rotor or impeller of the pump rotates in order to deliver the fluid. The heatable pump chamber may either have a heating means in the pump chamber as an additional part or alternatively a boundary or a wall of the pump chamber itself may be heated directly.
Such a heat-pump apparatus has the great advantage that the maximum possible heat recovery by means of the heat-pump apparatus is predetermined by design and by the temperature present at the heat source and the desired temperature for heating purposes. If these are insufficient, however, in order to achieve the desired heat recovery, then an additional heater is necessary. On the one hand, this may be provided in the building or room which is to be heated, that is to say completely independently of the heat-pump apparatus, although this increases the structural outlay. On the other hand, it is also possible to provide a heater in the collector circuit and/or in the heating circuit, and therefore the heating means of the heating circuit continue to be sufficient and also need not be changed. The disadvantage of providing a heating device in addition, however, is that the design of the heat-pump apparatus has to be changed and, in addition, it is necessary to install a further component with further electrical connections. Therefore, providing a pump with a directly heatable pump chamber according to the invention is a considerably more efficient and energy-saving option because no design changes have to be implemented in addition and there is no need to install any further component with further electrical connections.
The pump with a heatable pump chamber, is provided in the collector circuit, is preferably arranged upstream of the evaporator, as seen in the flow direction of the collector fluid. It is then also possible for the collector fluid to be heated still further once it has been heated by the heat source.
The collector pump is advantageously arranged just upstream of the evaporator. It is particularly advantageous if there are no further functional structural units located between the heatable pump and the evaporator and, in particular there is also only a short line, for example less than 1 m or even less than 0.5 m.
It is also the case with the heating circuit that, here, a heatable pump provided in the form of a heating pump should be arranged downstream of the condenser, and thus upstream of the heating means, as seen in the flow direction of the heating fluid. It is thus possible for the heating fluid, which has been heated via the heat exchanger in the refrigerant circuit and/or in the evaporator, to be heated somewhat more for the desired enhanced heating effect. The heated pump may be arranged just downstream of the condenser, so that the entire outlay which provides the connections is kept to a low level and to reduce difficulties which could arise as a result of being shifted closer to the heating means. It may also be the case here that there are no aforementioned functional structural units provided between the condenser and the heated pump, and the distance between the two is correspondingly small.
It is advantageously provided that the pump with a heatable pump chamber has a pump housing with the pump chamber therein. Heating means are provided on or in the pump chamber, it being possible for the heating means to form for example, as mentioned above, at least in part, a wall of the pump chamber. This is advantageously a largely encircling lateral wall, and the component provided is therefore a tubular, or at least partially tubular, heating means. It is also possible, however, for the heating means or for a heating element to be planar.
The heating means themselves may advantageously be designed in the form of a thick-film heating element. They can be applied directly, using a conventional method, to the wall of the carrier forming the pump chamber. This means that very high power densities are also possible.
In a further configuration of the invention, it is possible for the heating means to be designed in the form of, or with, a temperature sensor and have, for this purpose, a temperature-dependent electrical resistance. This is advantageously a negative temperature coefficient, and results in an NTC temperature sensor.
Heating the collector fluid and/or the heating fluid at the same time as the pumping operation and within the pump has the great advantage that this is energy-efficient and, at the same time, provides a very fast response time. At the same time, ready-integrated components may be provided for pumping and for heating purposes, which reduces the outlay in respect of production and, in particular, in respect of installation.
These and further features can be gathered not only from the claims but also from the description and the drawings, wherein the individual features can in each case be realized on their own or several combined together in an embodiment of the invention and in other areas and can constitute advantageous and independently patentable configurations for which protection is claimed here. Subdividing the application into sub-headings and individual sections does not restrict the general validity of what is said therebeneath or therein.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows a schematic illustration of a heat-pump apparatus according to the invention having a collector circuit, a refrigerant circuit and a heating circuit, and

FIG. 2 shows a schematic sectional view of a pump with a heatable pump chamber for delivering a fluid and heating the delivered fluid.

DETAILED DESCRIPTION

FIG. 1 illustrates a heat-pump apparatus 11 according to the invention for heating purposes. It has a collector circuit 13 with a collector line 14, which, in the left-hand region, leads through one of a number of heat sources, that is to say air 16 a, the ground 16 b or water 16 c. The collector line 14 leads into a heat pump 18, which is bordered by chain-dotted lines and should be, as it were, a functional unit, but is not necessarily a single structural unit, although this may be advantageous or it may advantageously be arranged in a housing.
A collector fluid 15 circulates in the collector line 14. This circulation is essentially generated by a pump 20, which may be either a quite normal pump or, advantageously, an aforementioned heated pump. Downstream of the pump 20, the collector line 14 leads to an evaporator 22, to be precise such that the heat removed from the heat source 16 can be dissipated by the collector fluid 15 to a refrigerant 23 in the evaporator 22. As a result of the heat, the refrigerant 23 is evaporated and flows through a compressor 24, in a compressed state, into a condenser 26, in which it is then liquefied again. It then flows on, through a pressure-relief valve 28, back into the evaporator 22.
At the condenser 26, the heat is dissipated from the refrigerant 23 to a heating circuit 30, to be precise to a heating fluid 32, which circulates in a heating line 31. For circulating purposes, a further pump 35 is provided, as heating pump, just downstream of the condenser 26. It is also possible for this pump 35, in a manner similar to that described previously for the collector pump 20, to be a normal pump or, advantageously, a pump with a heatable pump chamber. The heating line 31 then leads into a house 37 with a schematically illustrated radiator 38, which then dissipates the heat of the heating fluid 32 in a known manner to the surroundings in the house 37. The thus somewhat cooled heating fluid then flows back again, in the heating line 31, to the heat pump 18 and/or to the condenser 26.
As far as the respective temperatures are concerned, it may be the case, in one exemplary embodiment, that the temperature at the heat source, e.g. in the ground as the heat source 16 b, fluctuates between −1° C. and +2° C. The collector fluid 15 thus has essentially this temperature and therefore heats the refrigerant 23 at the evaporator 22, it being possible for the refrigerant to have a temperature of approximately −4° C. there. Upstream of the compressor 24, the refrigerant 23 may have a pressure of approximately 5 to 6 bar and a temperature of approximately 0° C. Downstream of the compressor, the pressure may be approximately 17 bar and the temperature approximately 36° C. In the condenser 26, the temperature of the refrigerant 23 is then still approximately 32° C., which then drops, just upstream of the pressure-relief valve 28, to approximately 25° C. The pressure remains at approximately 17 bar. Directly downstream of the pressure-relief valve 28, the pressure is then 5 to 6 bar, the same as mentioned above for the compressor 24, at a temperature of −4° C.
The heating fluid 31 is heated at the condenser 26, by the refrigerant 23, to approximately 35° C. and flows, at this temperature, into the radiator 38 in the house 37. At a temperature of approximately 27° C., the heating fluid 32 then flows back again to the heat pump 18 and/or to the condenser 26.
By virtue of one or both pumps 20, 35 being designed as a heated pump, it is also possible, ultimately, for the heating power thereof to be transferred to the heating fluid 32 and thus to the radiator 38. If the heating pump 35 is heated, this takes place directly and is evident straight away. If the collector pump 20 is heated, this higher or optimum temperature, in comparison with a non-heated pump, can also be transferred correspondingly to the refrigerant 23, which then indeed is in turn likewise warmer in the condenser 26 and thus increases the efficiency, so that the heating fluid 32 can also be heated to a more pronounced extent. It is therefore also expedient for a heated collector pump 20 to be installed just upstream of the evaporator 22, although it would also be possible for a collector pump 20′ (illustrated by dashed lines) to be provided just downstream of the evaporator 22, as in the prior art, so that structural modifications to the heat pump during the operation of integrating the heating pump are kept to a low level. The position 20′, however, is not optimum since the heating power would then be dissipated essentially also to the heat source 16 a to 16 c. Similarly, it would also be possible to provide a heating pump 35 just upstream of the condenser 26, in the position 35′ (illustrated by dashed lines). However, it would then also be the case here that the heat generated by the heater of the pump chamber is not used optimally.
Such use of heated pumps as a collector pump 20 and/or a heating pump 35 is recommended, in particular, in order to be able to supply peaks in consumption and/or during heating. Furthermore, it is also possible, if there is a relatively high proportion of wind power or solar power in the supply network or there is a local excess of power which is not currently required, for the power to be converted into more heat for heating purposes, to provide somewhat better heating, for example of the house 37. If the production of power then drops back again, the heating power can be operated some way below average, in which case desired heating is achieved overall on average. It is then possible for additional electric heaters or heating cartridges, which are otherwise provided for such a purpose, for example in the heating circuit 30 or a hot-water tank, to be dispensed with, and the same applies to the additional outlay required for installing and connecting the same. Furthermore, the operation of integrating a heater in the pump, and thus also in the moving stream of fluid, is very much more efficient. The pump and heater here can be coordinated optimally with one another, and this therefore also does away with the risk of any problems relating to system incompatibilities.
A further system-related advantage of a heated pump lies in the fact that, in the case where the heating means of the pump are designed or used in the form of, or with, a temperature sensor, as has been explained in the introduction, temperature monitoring can also be implemented to very good effect.
FIG. 2 illustrates, schematically, such a heated pump in the form of a heating pump 35. It has a pump housing 40 and a pump motor 42, which bears, and rotates, an impeller 45 on a motor shaft 43. The pump housing 40 also has a pump chamber 46 with an entry 48 and exit 50. In the pump chamber 46, the impeller 45 is enclosed by an annular heating means 52 with electrical connections 53. The heating means 52 may be, for example, a metallic ring and have thick-film heating elements applied to its outside, that is to say in a sealed state in relation to the fluid in the pump chamber 46. It is therefore the case here that the heating means 52 forms part of the pump chamber 46 or part of the wall thereof. It would also be possible, however, for the heating means 52 to form most of the pump-chamber wall; alternatively, it could also be arranged in the pump chamber with flow all around it, for example in the form of a round tubular heating element with a plurality of coils or loops. It is likewise conceivable for a planar heating element to be integrated in the pump chamber and for the pump to be heated in this way. Generally any kind of heater is conceivable for the pump, and also from moving parts thereon or therein.

Claims

That which is claimed:

1. A heat-pump apparatus for heating purposes, said heat-pump apparatus comprising:

a collector circuit for a heat source, said collector circuit having a collector fluid and a collector pump for said collector fluid;

a refrigerant circuit, said refrigerant circuit having a refrigerant in said refrigerant circuit, having an evaporator and a condenser for said refrigerant, having a compressor and a pressure-relief valve; and

a heating circuit, said heating circuit having a heating fluid and a heating pump for said heating fluid, and having heating means for heating purposes,

wherein said collector circuit interacts with said evaporator in order to dissipate heat to said refrigerant, wherein said condenser interacts with said heating circuit in order to dissipate heat from said refrigerant, and

wherein at least said collector pump or said heating pump is provided with a heatable pump chamber for heating said fluid delivered by said pump.

2. The heat-pump apparatus according to claim 1, wherein said collector pump comprises said heatable pump chamber and is arranged in said collector circuit upstream of said evaporator, provided in a flow direction of said collector fluid.

3. The heat-pump apparatus according to claim 2, wherein said collector pump is arranged just upstream of said evaporator.

4. The heat-pump apparatus according to claim 2, wherein said collector pump is arranged just upstream of said evaporator without any further functional structural units between said collector pump and said evaporator.

5. The heat-pump apparatus according to claim 1, wherein said heating pump comprises said heatable pump chamber and is arranged in said heating circuit downstream of said condenser, provided in a flow direction of said heating fluid, just downstream of the condenser and without any functional structural units therebetween.

6. The heat-pump apparatus according to claim 5, wherein said heating pump is arranged just downstream of said condenser.

7. The heat-pump apparatus according to claim 5, wherein said heating pump is arranged just downstream of said condenser without any further functional structural units between said heating pump and said condenser.

8. The heat-pump apparatus according to claim 1, wherein said pump with said heatable pump chamber comprises a pump housing with said pump chamber therein, wherein heating means are provided on or in said pump chamber.

9. The heat-pump apparatus according to claim 8, wherein said heating means form at least partly a wall of said pump chamber.

10. The heat-pump apparatus according to claim 9, wherein said wall of said pump chamber comprises an encircling lateral wall.

11. The heat-pump apparatus according to claim 8, wherein said heating means comprises thick-film heating elements.

12. The heat-pump apparatus according to claim 8, wherein said heating means comprises a temperature sensor with a temperature-dependent electrical resistance.

13. The heat-pump apparatus according to claim 8, wherein said heating means are provided with a temperature sensor, said temperature sensor comprising a temperature-dependent electrical resistance.

14. The heat-pump apparatus according to claim 13, wherein said temperature-dependent electrical resistance has a negative temperature coefficient.

15. A method of using a pump with a heatable pump chamber in a heat-pump apparatus for heating purposes, comprising:

16. A method of operating a heat-pump apparatus according to claim 1, wherein heat is absorbed from a heat source, such as air, water or the ground, by means of a collector fluid and wherein said collector fluid is pumped in a collector circuit, wherein said collector fluid dissipates its heat to a refrigerant in a heat exchanger, wherein said refrigerant is evaporated in an evaporator, wherein then said refrigerant is compressed, and heated in the process, and thereafter, in a condenser as a heat exchanger, dissipates its heat to a heating fluid of a heating circuit for heating purposes, wherein then said refrigerant is evaporated again and guided into said evaporator, and wherein said heating fluid is pumped in said heating circuit, wherein said collector fluid in said collector circuit or said heating fluid in said heating circuit is heated at the same time of a pumping operation and in said pump.

17. The method according to claim 16, wherein said pump with a heatable pump chamber is operated or said heating means thereof are operated, only when more heat is required for heating purposes than is generated by said heat-pump apparatus.

18. The method according to claim 17, wherein initially said heating means of said heating pump is operated, followed by said heating means of said collector pump.