Water-source heat pump system and method for operating same

Abstract

The invention relates to a water-source heat pump system (10) for using the thermal energy of the water (11) of a sea, lake or river, comprising a first heat exchanger (12), a compressor (13), a second heat exchanger (14) and an expander and / or a throttle (15), wherein the first heat exchanger (12) is designed to heat a heat pump process medium utilising the thermal energy of the water (11), wherein the compressor (13) is designed to compress the heat pump process medium downstream of the first heat exchanger (12) and upstream of the second heat exchanger (14), wherein the second heat exchanger (14) is designed to transfer heat from the heat pump process medium to a process medium (16) of a consumer, wherein the expander and / or the throttle (15) is designed to expand the heat pump process medium downstream of the second heat exchanger (14) and upstream of the first heat exchanger (12), wherein the first heat exchanger (12) is disposed either in the water (11) below the water surface (18) of the sea, lake or river or alternatively above the water surface (18) on a platform (23) located in the sea, lake or river, wherein the second heat exchanger (14), the compressor (13) and the expander and / or the throttle (15) are disposed on land, wherein the first heat exchanger (12) is connected to the compressor (13) and the expander and / or the throttle (15) disposed on land via a line system (20) for the heat pump process medium.

Description

[0001] MAN Energy Solutions SE

[0002] Water heat pump system and method for operating the same

[0003] The invention relates to a water heat pump system. Furthermore, the invention relates to a method for operating a water heat pump system.

[0004] A heat pump makes it possible to extract thermal energy from the environment and make this thermal energy available to a consumer. To do this, a heat pump uses a heat pump process medium that extracts thermal energy from the environment in a first heat exchanger and transfers the thermal energy to a consumer's process medium in a second heat exchanger. Heat pumps are generally divided into air-source heat pumps, geothermal heat pumps, and water-source heat pumps. Groundwater heat pumps, surface water heat pumps, and wastewater heat pumps are known as water-source heat pumps. A surface water heat pump uses the water from oceans, lakes, and rivers as the thermal energy source to operate the heat pump.

[0005] In conventional water-based heat pump systems, all components of the water-based heat pump system are located on land, with the water from the sea, lake, or river being pumped through a pipe system toward a first heat exchanger located on land to extract thermal energy from the water in the area of ​​the first heat exchanger. This can be very complex and entail high investment costs.

[0006] There is a need for a water heat pump system that utilizes the thermal energy of the water of a sea, a lake, or a river, which can be operated with lower investment costs and therefore more economically.

[0007] Based on this, the present invention is based on the object of creating a novel water heat pump system for utilizing the thermal energy of the water of a sea, a lake or a river and a method for operating the same.

[0008] This object is achieved by a water heat pump system according to claim 1 and by a method according to claim 7.

[0009] The water heat pump system according to the invention comprises a first heat exchanger, a compressor, a second heat exchanger, and an expander and / or a throttle. The first heat exchanger is configured to heat a heat pump process medium by utilizing the thermal energy of the sea, lake, or river water. The compressor is configured to compress the heat pump process medium downstream of the first heat exchanger and upstream of the second heat exchanger. The second heat exchanger is configured to transfer heat from the heat pump process medium to the process medium of a consumer. The expander and / or the throttle is configured to expand the heat pump process medium downstream of the second heat exchanger and upstream of the first heat exchanger.The first heat exchanger is located either below the water surface of the sea, lake, or river, or alternatively on a platform located in the sea, lake, or river above the water surface. The second heat exchanger, the compressor, and the expander and / or throttle are located onshore. The first heat exchanger is connected to the onshore compressor and the expander and / or throttle via a piping system for the heat pump process fluid.In the water heat pump system according to the invention, the water from the sea, lake, or river is not pumped towards a first heat exchanger of the water heat pump system arranged on land. Rather, the first heat exchanger is arranged either below the water surface of the sea, lake, or river or on a platform located in the sea, lake, or river, so that the water only has to travel a relatively short distance. In the invention, the heat pump process medium is instead pumped via the pipe system between the first heat exchanger and the components arranged on land. The first heat exchanger is therefore arranged away from the other components of the water heat pump system, so that the transfer of thermal energy from the water from the sea, lake, or river serving as the heat source is decoupled from the onshore components of the water heat pump system.This makes it possible to use a water heat pump system at lower costs and therefore more efficiently.

[0010] Preferably, the heat pump process medium is carbon dioxide. In the water heat pump system according to the invention, carbon dioxide CO2 is preferably used as the heat pump process medium. This is particularly preferred for the operation of the water heat pump system according to the invention.

[0011] According to a first variant, the first heat exchanger is arranged below the water surface of the sea, lake, or river at a depth at which the water of the sea, lake, or river is not frozen, even at low ambient air temperatures. For this purpose, the first heat exchanger preferably has a watertight housing that has inlets and outlets at least for the heat pump process medium. According to a second variant, the first heat exchanger is arranged on the platform located in the sea, lake, or river above the water surface, with a pump pumping the water from the sea, lake, or river to the first heat exchanger. For this purpose, an intake opening of the pump or of an intake pipe coupled to the pump is arranged in the water at a depth in the sea, lake, or river at which the water of the sea, lake, or river is not frozen, even at low ambient air temperatures.

[0012] Both variants provide a water heat pump system that can be used efficiently at low cost.

[0013] Preferred developments of the invention emerge from the subclaims and the following description.

[0014] Exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being limited thereto.

[0015] Fig. 1 a first water heat pump system,

[0016] Fig. 2 is a block diagram of the system of Fig. 1;

[0017] Fig. 3 a second water heat pump system,

[0018] Fig. 4 a third water heat pump system,

[0019] Fig. 5 is a block diagram of the system of Figs. 3 and 4.

[0020] Figs. 1 and 2 schematically show a first water heat pump system 10 according to the invention for utilizing the thermal energy of the water 11 of a sea, lake, or river. Such a water heat pump system 10 is also referred to as a surface water heat pump system. The water heat pump system 10 according to the invention comprises a first heat exchanger 12, a compressor 13, a second heat exchanger 14, and an expander (not shown) and / or a throttle 15, which are integrated into a thermodynamic, closed cycle of a heat pump.

[0021] The first heat exchanger 12 is configured to heat a heat pump process medium by utilizing the thermal energy of the sea, lake, or river water 11. The heat pump process medium can also be referred to as a refrigerant.

[0022] The compressor 13 is configured to compress the heat pump process medium downstream of the first heat exchanger 12 and upstream of the second heat exchanger 14 and to convey it in the direction of the second heat exchanger 14.

[0023] The second heat exchanger 14 is configured to transfer the thermal energy of the heat pump process medium to a consumer, namely to a process medium 16 used in the area of ​​the consumer.

[0024] The expander and / or the throttle 15 shown in Fig. 2 is configured to expand the heat pump process medium downstream of the second heat exchanger 14 and thereby at least partially liquefies it.

[0025] Starting from the expander and / or the throttle 15, the expanded, liquefied heat pump process medium can be transported back toward the first heat exchanger 12. Fig. 2 shows a separator 17 as a further component of the water heat pump system 10.

[0026] The separator 17 is configured to separate liquid heat pump process medium from gaseous heat pump process medium downstream of the expander and / or the throttle 15, wherein the liquid heat pump process medium can be transported in the direction of the first heat exchanger 12 and gaseous heat pump process medium can be transported in the direction of the compressor 13, bypassing the first heat exchanger 12.

[0027] In the embodiment of Figures 1 and 2, the first heat exchanger 12 is arranged below a water surface 18 of the sea, lake or river in the water 11 of the sea, lake or river, wherein for this purpose the first heat exchanger 12 preferably has a watertight housing 19.

[0028] The compressor 13, the second heat exchanger 14 as well as the expander and / or the throttle 15 are arranged on land, i.e. away and thus remote from the first heat exchanger 12, which is arranged within the water 11 serving as the heat source.

[0029] The first heat exchanger 12, which in Fig. 1, 2 is arranged below the water surface 18, is connected to the assemblies 13, 14, 15 arranged on land via a line system 20, wherein a first line 21 of the line system 20 serves to transport the heat pump process medium from the first heat exchanger 12 in the direction of the compressor 13 and a second line 22 of the line system 20 serves to transport the heat pump process medium from the expander and / or the throttle 15 in the direction of the first heat exchanger 12. In the water heat pump system 10' according to the invention, as already explained, the first heat exchanger 12, in the region of which thermal energy is extracted from the water 11, is not arranged on land, but remotely therefrom in the water 11.

[0030] Transport of the heat pump process medium can be carried out with less effort and at lower costs than the transport of water required in practice 11 .

[0031] The first heat exchanger 12 arranged below the water surface 18 within the water 11 in Fig. 1 and 2 is arranged at a depth of the sea, lake or river in which the water of the sea, lake or river is not frozen even at low ambient temperatures in winter.

[0032] As already explained, the first heat exchanger 12 has a watertight housing 19, which has inlets and outlets for at least the heat pump process medium. The piping system 20 is connected to the inlets and outlets for the heat pump process medium.

[0033] If the first heat exchanger 12 is a heat exchanger with passive or natural convection, water flows around it passively and the housing 19 does not require separate inlets and outlets for water.

[0034] A housing 19 with water inlets and outlets can also be used in conjunction with a first heat exchanger 12 with passive or natural convection to utilize a type of reverse chimney effect for the water flow. If the first heat exchanger 12 is a heat exchanger with active or forced convection, water actively flows around it, and the housing 19 preferably has separate water inlets and outlets. In this case, a pump, propeller, or the like is arranged in the area of ​​the water inlet or outlet to actively direct the water 11 through the first heat exchanger 12.

[0035] Fig. 3 and 4 each show schematic details of a second water heat pump system 10' according to the invention, with Fig. 5 showing further details of the same analogous to Fig. 2. To avoid unnecessary repetition, the same reference numerals are used for the same or similar components, and only those details are discussed below by which the variants of Figs. 3 to 5 differ from the variant of Figs. 1 and 2.

[0036] In the water heat pump systems 10' of Fig. 3 to 4, the first heat exchanger 12 is not arranged in the water, but on a platform 23 located in the sea, lake or river above the water surface 18, wherein a pump 24 pumps the water 11 from the sea, lake or river to the first heat exchanger 12 arranged on the platform 23 and this water is subsequently led back into the sea, lake or river after passing the first heat exchanger 12.

[0037] In Figs. 3 and 4, the platform 23 is firmly anchored to the seabed via a support structure 27. The support structure 27 can also be referred to as the foundation.

[0038] The foundation can be a foundation standing on the seabed, such as a jacket, a tripod, a gravity foundation, or a bucket foundation, or a foundation driven into the seabed, such as a monopile or a tripile. In contrast, a platform 23 that is not anchored to the seabed and thus floats on the water surface 18 can also be used. If the platform 23 floats on the water surface 18, the piping system 20 must compensate for any movement of the platform 23 while floating.

[0039] In Fig. 3, the pump 24, which pumps water 11 toward the first heat exchanger 12, is arranged directly in the water 11 below the water surface 18. In Fig. 4, this pump 24 is arranged together with the first heat exchanger 12 on the platform 23. The pump 24 can also be arranged or integrated within the support structure 27, such as in a monopile, below the water surface 18.

[0040] Both in Fig. 3 and in Fig. 4, a suction pipe 25 with a suction opening 26 is provided upstream of the respective pump 25, as seen in the flow direction of the water 11, wherein the suction opening 26 is arranged at a depth of the sea, lake or river at which the water of the sea, lake or river is not frozen even at low ambient temperatures in winter.

[0041] For example, the piping system 20 for the heat pump process medium can have a length of at least 50 meters, in particular at least 200 meters or 500 meters. Furthermore, the piping system can have a length of up to 1 kilometer, in particular up to 10 kilometers or even 100 kilometers. These length specifications are purely exemplary and depend on the specific application.

[0042] Preferably, the piping system 20 for the heat pump process medium extends at least partially or in sections in the water 11 of the sea, lake or river below the water surface 18. The length of the piping system for the heat pump process medium depends on the specific configuration of the water heat pump system 10, 10', in particular on whether sea water, river water or lake water is used as the heat source, and how far the onshore components 13, 14, 15 of the water heat pump system 10 are from the first heat exchanger 12.

[0043] The invention further relates to a method for operating a water heat pump system 10, 10' disclosed in Figs. 1 to 5. In the region of the first heat exchanger 12, liquid heat pump process medium is heated and evaporated. The evaporated, gaseous heat pump process medium is transported via the line system 20, namely the first line 21, toward the compressor 13.

[0044] In the area of ​​the compressor 13, the gaseous heat pump process medium is compressed, with heat subsequently being transferred from the compressed heat pump process medium to a process medium 16 of a consumer in the area of ​​the second heat exchanger 14. In the area of ​​the expander and / or the throttle 15, the heat pump process medium is expanded and liquefied, with the expanded and liquefied heat pump process medium being guided via the line system 20, namely the second line 22, toward the first heat exchanger 12.

[0045] In the area of ​​the first heat exchanger, the water from the sea, lake, or river flowing through the first heat exchanger 12 can be cooled to the freezing point of the water in order to at least partially freeze the water. This makes it possible to utilize not only sensible heat but also at least some of the water's latent heat for the water heat pump system 10, 10'.The water heat pump system 10, 10' according to the invention uses the heat pump process medium to transfer heat from a remote heat source, namely from the water 11, towards the second heat exchanger 14, the compressor 13 and the expander and / or the throttle 15, which are arranged on land, wherein the first heat exchanger 12 is arranged either below a water surface 18 of the sea, a lake or a river in the water 11 of the sea, lake or river or alternatively on a platform 23 located in the sea, lake or river above the water surface 18.

[0046] List of reference symbols

[0047] 10, 10' water heat pump system

[0048] 11 Water

[0049] 12 first heat exchanger

[0050] 13 Compressor

[0051] 14 second heat exchanger

[0052] 15 Throttle

[0053] 16 Process medium

[0054] 17 separators

[0055] 18 Water surface

[0056] 19 housings

[0057] 20 piping system

[0058] 21 first line

[0059] 22 second line

[0060] 23 Platform

[0061] 24 Pump

[0062] 25 Intake pipe

[0063] 26 Intake opening

[0064] 27 Supporting structure

Claims

Claims 1. A water heat pump system (10, 10') for utilizing the thermal energy of the water (11) of a sea, a lake, or a river, comprising a first heat exchanger (12), a compressor (13), a second heat exchanger (14), and an expander and / or a throttle (15), wherein the first heat exchanger (12) is configured to heat a heat pump process medium by utilizing the thermal energy of the water (11) of the sea, lake, or river, wherein the compressor (13) is configured to compress the heat pump process medium downstream of the first heat exchanger (12) and upstream of the second heat exchanger (14), wherein the second heat exchanger (14) is configured to transfer heat of the heat pump process medium to a process medium (16) of a consumer, wherein the expander and / or the throttle (15) is configured,to expand the heat pump process medium downstream of the second heat exchanger (14) and upstream of the first heat exchanger (12), wherein the first heat exchanger (12) is arranged either below a water surface (18) of the sea, a lake, or a river in the water (11) of the sea, lake, or river, or alternatively on a platform (23) located in the sea, lake, or river above the water surface (18), wherein the second heat exchanger (14), the compressor (13), and the expander and / or the throttle (15) are arranged on land, wherein the first heat exchanger (12) is connected to the compressor (13) arranged on land and the expander and / or the throttle (15) via a line system (20) for the heat pump process medium.

2. Heat pump system (10, 10') according to claim 1, characterized in that the heat pump process medium is carbon dioxide.

3. Water heat pump system (10') according to one of claims 1 to 2, characterized in that the first heat exchanger (12) is arranged on the platform (23) above the water surface (18), wherein a pump (24) pumps the water (11) to the first heat exchanger (12).

4. Water heat pump system (10') according to claim 3, characterized in that a suction opening (26) of the pump (24) or of a suction pipe (25) coupled to the pump (24) is arranged in the water (11) at a depth of the sea, lake or river at which the water (11) of the sea, lake or river is not frozen even at low ambient air temperatures.

5. Water heat pump system (10) according to one of claims 1 to 2, characterized in that the first heat exchanger (12) is arranged below the water surface (18) of the sea, lake or river in the water (11) at a depth at which the water (11) is not frozen even at low ambient air temperatures.

6. Water heat pump system (10) according to claim 5, characterized in that the first heat exchanger (12) has a watertight housing (19) which has inlets and outlets at least for the heat pump process medium.

7. A method for operating a water heat pump system (10, 10') according to one of claims 1 to 6, comprising the following steps: Heating and evaporating liquid heat pump process medium in the area of ​​the first heat exchanger (12), Transporting the evaporated, gaseous heat pump process medium via the pipe system (20) towards the compressor (13), Compression of the gaseous heat pump process medium in the compressor area (13) Transferring heat from the heat pump process medium to the consumer's process medium in the area of ​​the second heat exchanger (14), Relaxing and liquefying the heat pump process medium in the area of ​​the expander and / or throttle (15), Transporting the relaxed, liquid heat pump process medium via the pipe system (20) towards the first heat exchanger (12).

8. The method according to claim 7, characterized in that in the region of the first heat exchanger (12) the water (11) of the sea, lake or river is cooled in such a way that the water freezes at least partially.

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