U.S. patent application number 15/562974 was filed with the patent office on 2018-04-26 for energy store, power plant having an energy store, and method for operating the energy store.
The applicant listed for this patent is NATURSPEICHER GMBH. Invention is credited to Luis Deroi, Gerhard Ihle, Alexander Schechner.
Application Number | 20180112930 15/562974 |
Document ID | / |
Family ID | 55640738 |
Filed Date | 2018-04-26 |
United States Patent
Application |
20180112930 |
Kind Code |
A1 |
Schechner; Alexander ; et
al. |
April 26, 2018 |
Energy Store, Power Plant having an Energy Store, and Method for
Operating the Energy Store
Abstract
An energy storage device for a power plant includes a heat
exchanger arranged in a floating manner in a lower basin that is
fillable with water via a first supply line. A second supply line
supplies water from the lower basin. A third supply line is in
fluid communication with the heat exchanger. A heat pump provides
coolant to the heat exchanger via the third supply line such that
energy is extracted via the heat exchanger while freezing of the
water in the lower basin or in the form of sensible heat from the
water in the lower basin, wherein the energy is passed on to a
consumer for heat dissipation or for cold dissipation.
Inventors: |
Schechner; Alexander; (Ulm,
DE) ; Deroi; Luis; (Untergroeningen, DE) ;
Ihle; Gerhard; (Ulm, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATURSPEICHER GMBH |
Ulm |
|
DE |
|
|
Family ID: |
55640738 |
Appl. No.: |
15/562974 |
Filed: |
March 29, 2016 |
PCT Filed: |
March 29, 2016 |
PCT NO: |
PCT/EP2016/056808 |
371 Date: |
September 29, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y02E 20/14 20130101;
F28D 20/0043 20130101; Y02E 60/142 20130101; Y02B 10/70 20130101;
Y02B 10/20 20130101; F28D 20/02 20130101; Y02E 60/145 20130101;
F28D 2020/0078 20130101; F28D 20/021 20130101; F24D 11/0221
20130101; F01K 3/08 20130101; Y02E 60/14 20130101 |
International
Class: |
F28D 20/02 20060101
F28D020/02; F28D 20/00 20060101 F28D020/00; F01K 3/08 20060101
F01K003/08; F24D 11/02 20060101 F24D011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2015 |
DE |
10 2015 104 909.0 |
Claims
1-18: (canceled)
19. An energy storage device, comprising: a heat exchanger arranged
in a floating manner in a lower basin that is fillable with water
via a first supply line; a second supply line, wherein water is
supplied from the lower basin via the second supply line; a third
supply line in fluid communication with the heat exchanger; a heat
pump, wherein coolant is provided to the heat exchanger from the
heat pump via the third supply line such that energy is extracted
via the heat exchanger while freezing of the water in the lower
basin or in the form of sensible heat from the water in the lower
basin, the energy passed on to a consumer for heat dissipation or
for cold dissipation.
20. The energy storage device according to claim 19, with which the
heat exchanger is formed by pipes through which the coolant
flows.
21. The energy storage device according to claim 20, wherein the
pipes are arranged in the form of a spiral ring.
22. The energy storage device according to claim 21, further
comprising radially arranged struts that support the pipes arranged
in the spiral ring.
23. The energy storage device according to claim 19, wherein the
heat exchanger is surrounded by an outer wall that defines a
vertical partition around an outer circumference of the heat
exchanger such that the heat exchanger is formed as a ring-shaped
body.
24. The energy storage device according to claim 23, wherein the
ring-shaped body comprises a diameter of between 50 m to 200 m.
25. The energy storage device according to claim 19, wherein the
heat exchanger is anchored to a base of the lower basin.
26. The energy storage device according to claim 19, wherein the
heat exchanger is formed by pipes through which the coolant flows
and configured such that an ice layer forms in the heat exchanger
radially from an inside towards an outer circumference of the heat
exchanger.
27. The energy storage device according to claim 19, wherein the
heat exchanger further comprises an upper inlet through which water
is introduced into the heat exchanger above the ice layer during
freezing, such that the ice layer is located below the water
surface of the lower basin.
28. The energy storage device according to claim 27, wherein the
water supplied above the ice layer forms an insulating layer
between the ice layer and ambient air.
29. The energy storage device according to claim 27, wherein the
heat exchanger further comprises an air inlet through which air is
introduced to form an air cushion below the ice layer.
30. The energy storage device according to claim 26, wherein the
pipes are arranged in the heat exchanger such that multiple
superimposed layers of ice can be formed within the outer
circumference of the heat exchanger.
31. The energy storage device according to claim 30, wherein the
heat exchanger further comprises one or more air inlets or water
inlets disposed so as to form insulating layers of air or water
between the superimposed layers of ice.
32. A power plant, comprising: a lower basin of a pump storage
power plant that can be filled with water, the lower basin
connected to a pump via a first supply line and to an upper
reservoir via the pump and a supply line between the pump and the
upper reservoir; the lower basin further comprising an energy
storage device, the energy storage device comprising: a heat
exchanger arranged in a floating manner in the lower basin that is
fillable with water via the first supply line; a second supply
line, wherein water is supplied from the lower basin via the second
supply line; a third supply line in fluid communication with the
heat exchanger; and a heat pump, wherein coolant is provided to the
heat exchanger from the heat pump via the third supply line such
that energy is extracted via the heat exchanger while freezing of
the water in the lower basin or in the form of sensible heat from
the water in the lower basin, the energy passed on to a consumer
for heat dissipation or for cold dissipation.
33. The power plant according to claim 32, wherein the upper
reservoir is part of a wind power plant, and the pump is driven by
electrical energy generated by the wind power plant to pump water
from the lower basin into the upper reservoir.
34. A method for the operation of an energy storage device
according to claim 1, the method comprising controlling the heat
pump as a function of ambient temperature, solar radiation, and
water temperature, such that an ice layer is formed on the heat
exchanger when no energy can be extracted from the water
temperature of the lower basin.
35. The method according to claim 34, further comprising lowering
the ice layer in the water in the lower basin to protect the ice
layer from solar radiation.
36. The method according to claim 34, further comprising forming
multiple superimposed ices layers on the heat exchanger, wherein
the ice layer closest to a surface of the water in the lower basin
is a thin layer as compared to the other ice layers to absorb solar
radiation or to insulate the lower basin.
Description
FIELD OF THE INVENTION
[0001] The invention relates to an energy storage device, a power
plant with such an energy storage device, and a method for
operating the same.
BACKGROUND
[0002] Due to the increasingly scarce stocks of fossil fuels, the
use of renewable energy sources has been greatly expanded in recent
years. An increase in the use of renewable energy sources is also
predicted for the coming decades, since, in addition to rising raw
material prices, which will make the use of fossil fuels less
economical, the negative effects on the global climate connected
with the accumulation of carbon dioxide in the atmosphere is also
being considered in energy policy.
[0003] Various renewable energy sources are known from the general
state of the art, including, for example, the use of solar
radiation, wind power, or biomass. However, the first two sources
mentioned in particular are associated with the known drawback that
their use depends on external factors, such as available solar
radiation or available wind, but such factors are not correlated
with actual energy consumption. In order to remedy this situation,
several possibilities are known; on the one hand, rapidly
activatable power plants, which are typically based on fossil
fuels, are kept available, which power plants are able to
compensate for the emerging supply gap in the short term, and, on
the other hand, efforts are being undertaken to create efficient
energy storage that are able to temporarily store energy from
renewable sources electrically or mechanically and, if necessary,
are able to be introduced into a power grid.
[0004] An example of the mechanical storage of energy is provided
in DE 10 2011 050 032 A1. For the generation of electricity in wind
power plants and pump storage plants, the combination of such
plants is proposed in such a manner that a water storage tank is
installed in the interior of a tower of one or several wind power
plants, which tank serves as an upper water reservoir of the pump
storage plant.
[0005] DE 2 926 610 A1 discloses a storage device for providing the
input heat energy at a low temperature level for heat pump systems,
which absorb this energy and release it again at a higher
temperature level, whereas a water basin is designed in such a
manner that, through wall sloping and corresponding surface area
and reinforcement, its water content is able to freeze without
damaging the basin, and that a heat exchanger system located on the
basin floor or embedded into the basin floor enables the cooling
and freezing heat of such basin to be supplied to the cold side of
a heat pump.
[0006] Furthermore, DE 10 2010 037 474 A1 discloses a storage tank
device for an energy storage device system, comprising at least one
storage tank and at least one first heat exchanger medium, whereas
the storage tank features a housing containing a storage medium and
at least one first heat exchanger arrangement in contact with the
storage medium, whereas the at least first heat exchanger
arrangement features a first heat transfer medium. Within the
housing, at least one second heat exchanger arrangement is arranged
with a second heat exchanger medium, whereas the second heat
exchanger medium is essentially gaseous.
[0007] Thus, there is a need in the state of the art for an energy
storage device that can easily form a renewable energy generation
plant and that, in particular, can also be supplemented by a pump
storage power plant.
SUMMARY OF THE INVENTION
[0008] Therefore, it is a task of the invention to provide an
energy storage device that can work in combination with renewable
energy sources and can improve the overall yield of such a plant.
Additional objects and advantages of the invention will be set
forth in part in the following description, or may be obvious from
the description, or may be learned through practice of the
invention.
[0009] This task is solved by the characteristics of the
embodiments described herein, wherein such embodiments can be
combined with each other in a technologically sensible manner. The
description, in particular in connection with the drawing, further
characterizes and specifies the invention.
[0010] In accordance with the invention, an energy storage device
is provided, which features a heat exchanger that is arranged in a
floating manner on a lower basin formed as a lake and preferably
able to be filled with water via a first supply line, whereas, via
a second supply line, water can be supplied from the lower basin
and, via a third supply line, coolant of a heat pump penetrating
the heat exchanger can be supplied in separate circuits, such that
energy can be extracted from the lower basin while freezing of the
water of the lower basin or in the form of sensible heat from the
water of the lower basin, and can be passed on to a consumer for
heat dissipation and/or for cold dissipation.
[0011] Accordingly, the energy storage device is provided on the
surface of a lake, which can be designed, for example, as a lower
basin of a pump storage unit. Thus, the lower basin is provided
with an additional possibility of energy extraction, which is
utilized in the form of latent heat. By means of ice formation in
the lower basin, the latent heat can be utilized and re-dissipated
via the heat exchanger, for example for heating buildings at a
consumer's premises. In addition, the sensible heat present in the
water of the lake can also be extracted from the lower basin. For
this purpose, the lake can preferably be filled with water without
a natural inlet and via a first supply, such that solar radiation
causes an increase in temperature of the water in the lake. The
energy is extracted by means of a heat pump, which is preferably
supplied with electrical energy from an energy source that is
renewable or carbon dioxide-neutral. In particular, the heat pump
can also be fed by a generator of the pump storage unit. Thawing
typically occurs based on the prevailing environmental conditions,
such as solar radiation or temperature of the atmosphere. In other
embodiments, it may also be provided that thawing of the ice is
effected through the utilization of the cold in the ice, for
example for air conditioning during the spring or summer. In
accordance with the invention, the actual heat accumulator is the
lower basin. With this, the formation of ice is a possibility for
the utilization of the latent heat arising from the heat
accumulator formed as a lower basin.
[0012] The energy storage device features a wide range of possible
applications and operating modes, such that, depending on the
ambient temperature or the solar radiation that influences the
energy that can be extracted as sensible heat arising from the
lower basin, and depending on the energy demand according to the
season or projected for a consumer, the energy storage device is
either filled or emptied, whereas whether sensible or latent heat
is to be supplied to the consumer via the heat pump can be selected
at the time of extraction. By choosing the option when extracting
energy, an adjustment to the location and demand conditions can be
created.
[0013] The operation of the energy storage device in the seasonal
cycle preferably takes place in such a manner that, during the
energy input by solar radiation (that is, in northern latitudes,
typically from spring to autumn), a temperature spread takes place.
This reduces the radiating power of the surface of the lower basin
by cooling the water located therein. Herein, the temperature
spread relative to the ambient temperature is approximately in the
range from 5.degree. C. to 10.degree. C. A cooling phase of the
water in the lower basin to a temperature of approximately
0.5.degree. C. commences, in order to enable an ice-free transition
phase at the end of autumn (i.e., when the heating by solar
radiation is abating). During the winter time, the energy is
extracted through freezing on the surface of the lower basin. With
this, continuous heat generation can be achieved through a
sufficiently large selected volume of the ice due to the high
energy content for the crystallization of water to ice. During the
spring months until the early summer, the ice continues to melt on
the heat exchanger with a simultaneous reduction in energy
extraction, and the water temperature is further increased through
solar radiation. An important point is that, in certain weather
conditions, the ice layer formed after freezing can isolate the
water surface of the lower basin relative to the atmosphere, such
that its radiating power is thereby reduced.
[0014] Thus, in an advantageous manner, the concept described above
can be used for the supply of households with heat energy through
the supply of district heating, whereas approximately 40,000
m.sup.3 of ice must be provided for approximately 2000 to 4000
households, such that a natural lake would be adequately
dimensioned as a lower basin.
[0015] In accordance with one embodiment of the invention, the heat
exchanger is formed by pipes through which coolant flows.
[0016] Compared to surface elements, the provision of the heat
exchanger as pipes has the advantage that, at the beginning of the
formation of ice, the position of the crystallization point can be
selected through the positioning of the cold water inlet.
Accordingly, the initial freezing can be adjusted to the mechanical
requirements of the heat exchanger in order to, for example, avoid
or greatly reduce mechanical stresses compared to uncontrolled
freezing.
[0017] In accordance with an additional embodiment of the
invention, the pipes are arranged in the form of a ring spiral.
[0018] A ring spiral can be adjusted in shape and size to the shore
line of the lower basin, which is formed as a natural lake, in
order to make good use of the surface of the lower basin. With a
circular or nearly circular lower basin, the ring spiral may be
bounded by a circular outer line. However, elliptical or
rectangular outer lines are also possible.
[0019] In accordance with an additional embodiment of the
invention, radially arranged struts support the pipes arranged in
the form of the ring spiral.
[0020] Such an approach enables a stable, yet material-saving
arrangement of the ring spiral of the heat exchanger. This is also
important, as the heat exchanger is arranged in a floating and
mobile manner on the water surface, such that the heat exchanger is
exposed to changing forces when changes in the water level occur,
whereas the heat exchanger is to, for example, also withstand
extreme situations such as flooding in the case of high water.
[0021] In accordance with an additional embodiment of the
invention, the heat exchanger is surrounded by an outer wall that
surrounds the heat exchanger along its outer circumference in the
form of a vertical partition, such that a ring-shaped body is
formed.
[0022] In order to separate the heat exchanger with the ice that
may be present therein from the water of the lower basin, in
accordance with the invention, it is not provided to form a closed
volume, as is the case with known energy storage device systems
based on the crystallization of water. In accordance with the
invention, it is quite advantageous to leave the upper side and the
lower side of the heat exchanger uncovered, as will be explained
further below.
[0023] In accordance with an additional embodiment of the
invention, the ring-shaped body has a diameter of approximately 50
m to 200 m, preferably approximately 100 m.
[0024] The dimensioning according to this embodiment enables the
formation of several tens of thousands of cubic meters of ice,
which would enable several thousand households to be supplied. The
energy stored in this volume of ice corresponds to a heat output of
some GWh. Here, the exact dimensioning can be selected or adjusted
accordingly, taking into account the boundary conditions such as
area needs, energy needs and available electrical power for
operating the heat pump.
[0025] In accordance with an additional embodiment of the
invention, the heat exchanger can be connected by means of an
anchoring to a base of the lower basin.
[0026] With this, preferably in the center of the heat exchanger,
an attachment option is provided along a post-like anchoring that
is fixed to the base of the lower basin, whereas the heat exchanger
is axially displaceable on the anchoring as a function of the water
level in the lower basin. In addition to or in place of the
post-like anchoring, the heat exchanger can be held at the base of
the lower basin or in the area of the embankment through suitably
prestressed tensioning cables, which are preferably attached to the
aforementioned spokes or the outer wall.
[0027] The prestressing of the tensioning cables or the position of
the heat exchanger on the post-like anchoring can also be
adjustable by means of an external control.
[0028] In accordance with an additional embodiment of the
invention, an ice layer forms in the heat exchanger radially from
the inside to the outside, and, if applicable, subsequently
increases in thickness.
[0029] The stability of the floating heat exchanger is increased
through the radial formation of the ice layer from the inside to
the outside, such that no or little complicated additional measures
have to be taken for the balancing of the heat exchanger during the
freezing on the lower basin. For this purpose, the cooling medium
is supplied from the heat pump into the middle of the heat
exchanger. Accordingly, the radial formation of the ice layer
initially takes place, in order to obtain a closed ice layer.
Subsequently, the thickness of the ice layer above and below the
pipes of the heat exchanger is increased. With this, forming the
ice layer approximately up to 1 m on each side of the pipes is
provided. The ice layer serves, on the one hand, to provide a cold
accumulator for cooling in the summer, in order to be able to carry
out cold extraction. However, as already described above, the
formation of ice is also an option for extracting heat from the
water of the lower basin.
[0030] In accordance with an additional embodiment of the
invention, the heat exchanger features an upper inlet, through
which, during freezing, water can be introduced into the heat
exchanger on the resulting ice layer, such that the ice layer is
located below the water surface of the lower basin.
[0031] This approach makes it possible to, when the ice layer is
present, provide an additional load, such that the heat exchanger
sinks in the lower basin, and the ice layer comes to lie below the
water surface of the lower basin. This ensures that, despite an ice
layer, even when exposed to sunlight the water temperature in the
lower basin is not kept unnecessarily low, but can in fact
increase, since the solar radiation is absorbed in the area of the
water surface as the temperature of the water near the surface
increases, such that only a small energy input is introduced into
the ice layer.
[0032] In accordance with an additional embodiment of the
invention, an insulating layer is arranged between the ice layer
and the cold water that is able to be supplied.
[0033] This results in a decoupling from the ice layer to the
environment, which in particular reduces the heat exchange, such
that the ice layer is retained for a longer period of time.
[0034] In accordance with an additional embodiment of the
invention, an air cushion can be formed below the ice layer and on
the side of the ice layer turned away from the water surface.
[0035] This results in a decoupling from the ice layer relative to
the water of the lower basin, which in particular reduces the heat
exchange, such that the ice layer is retained for a longer period
of time.
[0036] In accordance with an additional embodiment of the
invention, a multiple number of superimposed ice layers can be
formed independently of one another.
[0037] As a result, a larger volume of the ice layer can be formed,
whereas the individual ice layers can also serve individually as
energy carriers, and can be used separately, depending on the
requirements of the consumers for the supply of district heating.
Furthermore, in a multi-layer system, the uppermost layer may
constitute a type of "rapid freezing." That is, a thin layer of ice
can be rapidly formed in the uppermost layer. This can be formed
approximately up to 10 cm on each side of the cooling pipe. Such
layer can cover power peaks, but also be used to isolate the lower
basin from the atmosphere. The idea with rapid freezing is that,
for example, an ice layer is formed overnight in order to isolate
the lower basin from the atmosphere, while water is pumped over the
ice during the day in order to absorb solar radiation and melt the
thin ice layer. Thus, if the energy balance is positive (for
example, during the day), the rapid freezing is to serve as a solar
collector and, if the energy balance is negative (for example, a
cold night), the rapid freezing is to serve as insulation. As a
result, "warm" water is quickly obtained in the collector, and a
high degree of efficiency is obtained at the heat pump. At night,
due to the insulation little energy is lost to the atmosphere.
[0038] In accordance with an additional embodiment of the
invention, directly adjacent ice layers are separated by insulating
layers.
[0039] This results in a decoupling of the ice layer relative to
the environment, which in particular reduces the heat exchange,
such that the ice layer is retained for a longer period of
time.
[0040] In addition, a power plant comprising a lower basin of a
pump storage power plant that can be filled with water is
specified, whereas the lower basin is connected to a pump via a
first supply line and to an upper reservoir via a supply line that
passes through the pump storage power plant and can be connected to
the first supply line, whereas the lower basin is provided with an
energy storage device described above.
[0041] This approach ensures a significantly improved energy
balance since, in addition to the storage in the pump storage
plant, energy storage is also carried out in any event for the pump
storage plant in the already existing lower basin. At this, the
required power of the energy storage device is provided by the pump
storage plant.
[0042] In accordance with one embodiment, the upper reservoir is
part of a wind power plant, whereas the pump can be driven by means
of electrical energy generated by the wind power plant, in order to
pump water from the lower basin into the upper reservoir.
[0043] In particular, the alternating power of the wind power plant
due to changing wind conditions can be compensated to a certain
degree by the pump storage plant, such that the pump storage plant
can deliver power during periods of low wind and can store energy
in the case of excess power of the wind power plant.
[0044] This approach ensures a significantly improved energy
balance since, in addition to the storage of the alternating power
of the wind power plant in the pump storage plant, energy storage
is also carried out in any event for the pump storage plant in the
already existing basin. At this, the required power of the energy
storage device is provided by the pump storage plant.
[0045] Finally, a method for operating such an energy storage
device is indicated; with such method, the heat pump is controlled
as a function of ambient temperature, solar radiation and water
temperature, such that the ice layer is formed on the heat
exchanger when no energy can be extracted from the water
temperature of the lower basin.
[0046] In accordance with one embodiment of the method, the
lowering of the ice layer through water load can additionally be
carried out, in order to protect the ice layer from solar
radiation.
[0047] By controlling the water load via the upper supply line, the
effect of solar radiation on the ice layer can be reduced. As a
result, the solar radiation can be absorbed by the water, since,
for the most part, ice reflects the solar radiation. As a result,
the irradiated energy quantity in the lower basin increases
considerably compared to a situation with an ice layer floating on
it.
[0048] In accordance with an additional embodiment of the method,
the energy storage device may feature a multi-layer structure,
whereas the layer closest to the water surface is initially used to
form an ice layer, which is preferably thin.
[0049] Accordingly, in a multi-layer system, the uppermost layer
may constitute a type of "rapid freezing." That is, a thin layer of
ice can be rapidly formed in the uppermost layer. This can be
formed approximately up to 10 cm on each side of the cooling pipe.
Such layer can cover power peaks, but also be used to isolate the
lower basin from the atmosphere. The idea with rapid freezing is
that, for example, an ice layer is formed overnight in order to
isolate the lower basin from the atmosphere, while water is pumped
over the ice during the day in order to absorb solar radiation and
melt the thin ice layer. Thus, if the energy balance is positive
(for example, during the day), the rapid freezing is to serve as a
solar collector and, if the energy balance is negative (for
example, a cold night), the rapid freezing is to serve as
insulation. As a result, "warm" water is quickly obtained in the
collector, and a high degree of efficiency is obtained at the heat
pump. At night, due to the insulation little energy is lost to the
atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Some embodiments are explained in more detail below on the
basis of drawings. The following is shown:
[0051] FIG. 1 is a schematic presentation of a power plant in
accordance with the invention for realizing the invention;
[0052] FIG. 2 is an energy storage device in accordance with the
invention in a schematic representation;
[0053] FIG. 3 is a heat exchanger as a component of an energy
storage device in accordance with the invention in a perspective
side view;
[0054] FIG. 4 is the heat exchanger of the embodiment in accordance
with FIG. 3 in a side view;
[0055] FIG. 5 is the heat exchanger of the embodiment in accordance
with FIG. 3 in an additional side view;
[0056] FIG. 6 is the heat exchanger of the embodiment in accordance
with FIG. 3 in an additional side view; and
[0057] FIG. 7 is the heat exchanger of the embodiment in accordance
with FIG. 3 in an additional side view.
[0058] In the figures, identical or functionally equivalent
components are provided with the same reference sign.
DETAILED DESCRIPTION
[0059] Reference will now be made to embodiments of the invention,
one or more examples of which are shown in the drawings. Each
embodiment is provided by way of explanation of the invention, and
not as a limitation of the invention. For example features
illustrated or described as part of one embodiment can be combined
with another embodiment to yield still another embodiment. It is
intended that the present invention include these and other
modifications and variations to the embodiments described
herein.
[0060] In FIG. 1, a first embodiment of the invention is shown
below. FIG. 1 schematically shows a power plant, which comprises
one or several wind power plants WKA. The wind power plants WKA are
arranged on a mountain ridge, for example, over a river valley or
the like. A pump storage power plant KR is located below the wind
power plants WKA, whereas the pump storage power plant KR is
connected via a supply line LT to an upper reservoir OR of the wind
power plants WKA. The upper reservoir may be formed, for example,
as a basin, in which the individual wind power plants are arranged,
such that the upper reservoir OR forms a foundation for the wind
power plant WKA. In other embodiments, the upper reservoir OR can
be integrated in a mast of the wind power plant WKA, or can be
designed as a separate storage device adjacent to the wind power
plant WKA.
[0061] Furthermore, the pump storage power plant KR features a
generator GE, which is connected to the supply line LT and is
formed in such a manner that water, which is fed from the upper
reservoir OR via the supply line LT through the generator GE into a
lower basin UB, can be converted into electrical power. In the
opposite direction, water can be pumped from the lower basin UG to
the upper reservoir via a first supply line ZU1 and a pump PU. The
generator GE is connected to a power grid SN, such that the
generated electrical energy can be fed.
[0062] Furthermore, the pump storage power plant KR features an ice
layer EI in the lower basin UB, which, as will be explained in more
detail below, is arranged on the surface of the lower basin UB
filled with water WA, as indicated by the arrow PF in FIG. 1. The
lower basin UB filled with water WA is connected to a heat pump WP
via a second supply line ZU2.
[0063] In other embodiments, the lower basin UB can also be
realized without a pump storage power plant KR; that is, for
example, as a lake or generally as surface water.
[0064] A coolant for forming the ice layer EI can also be supplied
via a third supply line ZU3 through the heat pump WP to a heat
exchanger WTA arranged in the lower basin UB. Through the
extraction of sensible heat from the water WA of the lower basin UB
or through the extraction of latent heat from the ice layer EI in
the lower basin UB, the heat pump WP generates heat that can be
supplied to a multiple number of consumers VR in the form of
district heating FW.
[0065] The heat pump WP requires electrical power, which can be
provided, for example, by the generator GE. The heat pump WP is
preferably located within the pump storage power plant KR or is
arranged immediately adjacent thereto. The pump PU is
advantageously supplied with the electrical power emitted by the
wind power plants WKA.
[0066] The lower basin UB, together with the ice layer EI along
with the water WA present in the lower basin UB, forms, together
with the heat pump WP, an energy storage device EN.
[0067] FIG. 2 schematically shows the energy storage device EN,
whereas, in accordance with FIG. 2, the individual liquid flows
between the different components are shown in detail.
[0068] The lower basin UB forms a component of the pump storage
power plant KR via the first supply line ZU1. Via the first supply
line ZU1, water WA can thus be supplied to the lower basin UB or
extracted from the lower basin UB, in order to be conducted via the
pump PU into the upper reservoir OR. Furthermore, water WA of the
lower basin UB is supplied via the second supply line ZU2 to the
heat pump WP. The supply is indicated in FIG. 2 as ZU2-H. The
return line, which allows the water WA contained in the lower basin
UB to cool, typically after flowing through the heat pump WP, is
marked with the reference sign ZU2-R in FIG. 2. The cooled water,
on the one hand, can reach the lower basin UB via the supply line
ZU2-R'. Furthermore, it is possible to supply the cooled water via
the upper supply line ZL to the heat exchanger WTA.
[0069] In a separately operating circuit of the heat pump WP,
cooling liquid is supplied to the heat exchanger WTA via the third
supply line ZU3. Here, the cooling liquid reaches the heat
exchanger WTA via the supply line marked with the reference sign
ZU3-H; in FIG. 2, the return line is indicated by the reference
sign ZU3-R. As already mentioned, the heat pump WP is
advantageously supplied with electrical power via the generator GE.
The heat pump WP delivers district heating FW to the consumers VR,
as explained in connection with FIG. 1.
[0070] A possible embodiment of the heat exchanger WTA will be
described below with reference to FIG. 3. The heat exchanger WTA is
arranged in a floating manner on the lower basin UB filled with
water WA, and includes pipes RO arranged in the form of a ring
spiral. To the outside, the heat exchanger WTA is bounded by an
outer wall AW, which surrounds the heat exchanger WTA along its
outer circumference. The pipes RO and the outer wall AW are held
via radially arranged spokes SRC. The upper supply line ZL is
arranged above the pipes RO on the outer wall AW.
[0071] In FIG. 3, the position of the supply of the cooling liquid
via the third supply line ZO3-H is also indicated. By introducing
the cooling liquid into the center of the pipes RO arranged in the
form of a ring spiral, the water WA located in the lower basin UB
can be cooled, such that the ice layer EI is able to form around
the pipes RO. In this case, freezing takes place viewed radially
from the inside outwards, which in particular increases the
stability of the heat exchanger WTA floating on the lower basin UB.
The thickness of the ice layer in the heat exchanger WTA can be
controlled over the duration of the supply line or the temperature
of the cooling liquid.
[0072] The embodiment of the heat exchanger WTA shown in FIG. 3 is
once again shown in a side view with reference to FIG. 4. The side
view according to FIG. 4 takes place along a radial section, which
leads through the center of the heat exchanger WTA. It can be seen
that the supply of the third supply line ZU3-H is arranged near the
center of the heat exchanger WTA. The return (that is, the third
supply line ZU3-R) is located closer to the outer wall AW.
[0073] The upper supply line ZL is arranged above the ring spiral
RS. With this, the outer wall AW is designed in such a manner that
the ring spiral RS is completely covered with respect to its
height, such that individual sub-areas, which are also components
of the heat exchanger WTA, are provided above the ring spiral RS
and below the ring spiral RS. In the sub-area located below the
ring spiral RS, air can be directed into the heat exchanger WTA via
an air supply LZ, which will be explained below.
[0074] In order to enable a floating arrangement of the heat
exchanger WTA in the lower basin UB, a post-like anchoring (not
shown in FIG. 4) is provided; this is fastened to a base of the
lower basin UB with its lower end. Along this post-like anchoring,
the heat exchanger WTA can be moved axially, depending on the water
level in the lower basin UB. This is illustrated schematically by a
fastening point BS in FIG. 4, which is connected to the post-like
anchoring through suitably movable connecting means. In place of
the post-like anchoring, or also in addition to the post-like
anchoring, the heat exchanger WTA can be connected to the bottom of
the lower basin UB via suitably prestressed tensioning cables (not
shown in FIG. 4). The tensioning cables can also be locked in the
area of the shore of the lower basin UB.
[0075] The function of the heat exchanger WTA is explained in more
detail below with reference to a first example.
[0076] FIG. 5 in turns shows the heat exchanger WTA in the lower
basin UB filled with water WA. By supplying the coolant, the ice
layer EI, which is bounded radially outwards by the outer wall AW,
forms along the pipes RO. The latent heat can be utilized by means
of ice formation in the lower basin in the form of the ice layer EI
and can be re-dissipated via the heat exchanger WTA, for example
for heating buildings at a consumer's premises. In order to
preserve the ice layer EI when there is solar radiation, water WA
is pumped via the upper inlet ZL, preferably via the cold water
return ZU2-R, to the surface of the ice layer EI, such that the
weight of the heat exchanger WTA is increased. Consequently, the
ice layer EI sinks below the water surface of the water WA in the
lower basin UB, and the layer of water WA arranged above the ice
layer EI prevents solar radiation from directly striking the ice
layer EI. Accordingly, the ice layer EI is decoupled from ambient
air UL, such that the solar radiation is absorbed by the water in
the lower basin UB. This increases the irradiated energy quantity,
because otherwise the solar radiation would be largely reflected by
the ice.
[0077] The concept presented in FIG. 5 is continued in FIG. 6, in
which an insulation layer IS is arranged between the water layer
WA, which arrives in the heat exchanger WTA via the upper inlet ZL,
and the ice layer EI, which insulation layer IS provides for
further improvement with respect to the decoupling against the
ambient air UL.
[0078] FIG. 7 shows an alternative embodiment with which, in
particular, the insulation against the water WA in the lower basin
UB is considered. Via the air supply LZ, an air cushion LT can be
formed below the ice layer EI, which acts as insulation against the
water WA of the lower basin UB.
[0079] However, the embodiments explained in connection with FIG. 5
to FIG. 7 can also be combined such that, for example, an
insulation layer SI along with an air cushion LP can be formed.
Furthermore, it is possible to install the pipes RO of the heat
exchanger WTA in several levels, such that a multiple number of ice
layers EI lying parallel one above the other are formed in the heat
exchanger WTA. The individual adjacently arranged ice layers EI can
be insulated from one another via insulation layers, similar to the
insulation layer IS from FIG. 6. Furthermore, with the multi-layer
construction, each layer can be provided with its own supply for
the coolant, such that each layer can be controlled independently
of the others. In this case, in particular, the uppermost layer can
form a rapid-freezing level. For this purpose, a thin layer of ice
can be formed quickly in the uppermost layer. This can be formed
approximately up to 10 cm on each side of the cooling pipe. Such
layer can cover power peaks, but also be used to isolate the lower
basin from the atmosphere. The idea with rapid freezing is that,
for example, an ice layer is formed overnight in order to isolate
the lower basin from the atmosphere, while water is pumped over the
ice during the day in order to absorb solar radiation and melt the
thin ice layer. Thus, if the energy balance is positive (for
example, during the day), the rapid freezing is to serve as a solar
collector and, if the energy balance is negative (for example, a
cold night), the rapid freezing is to serve as insulation. As a
result, "warm" water is quickly obtained in the collector, and a
high degree of efficiency is obtained at the heat pump. At night,
due to the insulation only little energy is lost to the
atmosphere
[0080] The operation of the energy storage device EN in the
seasonal cycle takes place in such a manner that, during the energy
input by solar radiation (that is, in northern latitudes, typically
from spring to autumn), a temperature spread takes place. This
reduces the radiating power of the surface of the lower basin UB by
cooling the water WA contained therein through the heat pump WP.
The temperature spread relative to the ambient temperature of the
ambient air UL is approximately in the range from 5.degree. C. to
10.degree. C.
[0081] A cooling phase of the water WA in the lower basin UB to a
temperature of approximately 0.5.degree. C. commences, in order to
enable an ice-free transition phase at the end of autumn (i.e.,
when the heating by solar radiation is abating).
[0082] During the winter time, the energy is extracted through
freezing on the surface of the lower basin UB; that is, via the ice
layer EI in the heat exchanger WTA. At this, continuous heat
generation can be achieved via the heat exchanger WTA with the heat
pump WP through a sufficiently large selected volume of the ice
layer EI due to the high energy content for the crystallization of
water WA to ice in the ice layer E.
[0083] During the spring months until the early summer, the ice of
the ice layer EI continues to melt on the WTA heat exchanger with a
simultaneous reduction in energy extraction, and the water
temperature of the water WA in the lower basin UB is increased
through solar radiation.
[0084] Thus, in an advantageous manner, the concept described above
can be used for the supply of households with heat energy through
the supply of district heating, whereas approximately 40,000
m.sup.3 of ice must be provided for approximately 2000 to 4000
households, such that a natural lake would be adequately
dimensioned as a lower basin UB.
[0085] The existing ice of the ice layer EI can also be used for
cooling at the premises of the consumer VR during times of high
ambient temperatures.
[0086] The characteristics described above and the characteristics
that are indicated in the claims and can be extracted from the
figures can be advantageously realized both individually and in
various combinations. The invention is not limited to the described
embodiments, but can be modified in many ways within the scope of
the skilled art.
* * * * *