Note: Descriptions are shown in the official language in which they were submitted.
CA 02786157 2014-04-30
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1
DEVICE FOR TEMPERATURE CONTROL OF A ROOM
The invention relates to a device and a method for the
temperature control of a room.
So-called concrete core activation systems are known
from the prior art for the air conditioning of rooms
having concrete ceilings or concrete walls. In these
systems pipes carrying heating or cooling media are
mounted in, below or on the concrete ceiling or the
concrete wall. By storing the heating or cooling energy
in the concrete mass of the ceiling or the walls and a
time-delayed delivery of the stored heating or cooling
energy, an energy-efficient air conditioning of the
rooms can be achieved. Thus, for example, at night a
cooling fluid (for example, water) is cooled and passed
through the pipes in a concrete core activated ceiling
or wall whereby the ceiling or the wall is slowly
cooled. The cooling energy stored in the concrete
ceiling or wall can then be released into the room
during the day in particular in the warm summer months,
to slowly lower the room temperature in the room.
However, the installation of such thermally activatable
ceilings or walls is restricted to new buildings. When
renovating old buildings, such concrete core activation
of the ceilings or walls cannot be installed
subsequently. In the case of ceilings or walls with
concrete core activation it is furthermore
disadvantageous that pipes laid in the concrete ceiling
or wall could be unintentionally damaged, for example,
by the drilling of holes. Repair of damaged pipes is
scarcely possible since the pipes embedded in concrete
are difficult to access for a repair. The statics and
the stability of ceilings or walls provided with pipes
also suffer from the pipes embedded in concrete.
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Furthermore, the manufacture of such concrete core
activation systems is very time consuming and costly.
Another disadvantages lies in the inertia of the
thermal system which is based on the time-delayed
release of the thermal energy stored in the concrete
accumulator mass to the room to be temperature
controlled.
In order to eliminate these disadvantages, temperature
control systems are known from the prior art which can
also be provided subsequently on pipe-free ceilings or
walls. These temperature control systems usually
comprise ceiling or wall elements in which pipes are
disposed which can be acted upon with a heating or
cooling medium. These ceiling or wall elements are
fixed to the ceiling or wall. The thermal energy stored
in the heating or cooling medium which is passed
through the pipes is diverted via a frame or a lining
of the ceiling or wall elements in to the room to be
temperature controlled by thermal radiation and free
convection. Such a system is described for example in
EP 1371915 Al in which phase change materials are used
as thermal accumulators.
These temperature control systems have the disadvantage
that the thermal energy from the heating or cooling
medium flowing into the pipelines is released directly
and instantaneously by thermal radiation and convection
into the room. In these temperature control systems the
surfaces of the ceilings or the walls are also occupied
by the ceiling or wall elements. This has the result
that the ceiling or wall surface is thermally separated
from the room to be temperature controlled which is why
the mass of the ceilings or the walls cannot be used
for storage cooling (or heating) in the night.
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Starting from this, it is the object of some embodiments of the
present invention to provide a device and a method for the
temperature control of a room in which the mass of the ceilings
or walls can be used as a thermal accumulator without pipes for
the passage of a heating or cooling medium for thermal
actuation of the accumulator needing to be incorporated in the
ceilings or walls. It is furthermore the object of some
embodiments of the invention to provide the most energy-
efficient temperature control system with short response times.
Furthermore, it should be made possible to install these
temperature control systems subsequently, including when
renovating old buildings.
In some embodiments, the invention relates to a device for
temperature control of a room with at least one component,
which forms a thermal accumulator and has a surface pointing
into the room, the device comprising pipes thermally coupled to
the component, which can be acted upon by means of a heating or
cooling medium, wherein the pipes are embedded in a panel,
which contains expanded graphite or consists of expanded
graphite, and the panel is in flat thermal contact with the
surface of the component pointing into the room, wherein the
panel is disposed in a frame fixed to the component, and
wherein the frame is configured as a cassette which is open at
one side.
In some embodiments, the invention relates to a method for
temperature control of a room bounded at least on one side by a
component, wherein the component has a surface pointing into
the room and the mass of the component forms a thermal
accumulator which is thermally coupled to pipes through which a
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heating or cooling medium is passed, wherein the pipes are
embedded in a thermally conducting panel containing expanded
graphite or consisting of expanded graphite, wherein the panel
is disposed in a frame fixed to the component, wherein the
frame is configured as a cassette which is open at one side,
and wherein the panel is in flat thermal contact with the
surface of the component pointing into the room, the method
comprising: transferring by heat conduction at least a part of
the thermal energy stored in the heating or cooling medium from
the pipes via the thermally conducting panel to the thermal
accumulator for intermediate storage; and delivering the part
of the thermal energy from the thermal accumulator to the room
in a time-delayed manner.
The invention is explained in detail hereinafter by means of
exemplary embodiments with reference to the accompanying
drawings. In the drawings:
Figure 1: shows a schematic sectional view of a device
according to the invention for temperature control of a room in
a first embodiment;
Figure 2: shows a schematic sectional view of a ceiling or wall
element for a temperature control device according to the
invention in a second embodiment;
Figure 3: shows a schematic sectional view of the second
embodiment of a temperature control device according to the
invention with the ceiling or wall element from Figure 2.
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Figure 1 shows a first embodiment of a temperature
control device according to the invention. This
comprises an element 10 provided on a component 5 made
of concrete or brick. The component 5 can comprise a
ceiling or a wall or a floor of the room R to be
temperature controlled. The component 5 can also be
constructed from another conventional building material
that is capable of storing heat and/or cold, such as
clay or natural stone. The element 10 then accordingly
comprises a ceiling, wall or a floor element which is
disposed on the surface 11 of the component 5 pointing
into the room. As a result of its large mass, the
component 5 forms a thermal accumulator in which
thermal energy (in the form of heat or cold) can be
stored.
The element 10 comprises a panel 1 containing expanded
graphite or consisting completely of expanded graphite.
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5a
The production of expanded graphite (expanded graphite) is
known inter alia from US 3,404,061-A. In order to produce
expanded graphite, graphite intercalation compounds or graphite
salts such as, for example, graphite hydrogen sulphate or
graphite nitrate are heated in a shock manner. The volume of
the graphite particles is thereby increased by a factor of
about 200 - 400 and at the same time the bulk density decreases
to values of 2 - 20 g/l. In some embodiments, the density of
the panel 1 lies between 0.04 and 0.10 g/cm3. The expanded
graphite thus obtained consists of worm- or concertina-shaped
aggregates. If completely expanded graphite is compacted under
the directional action of pressure, the layer planes of the
graphite are preferably arranged perpendicular to the direction
of action of the pressure, where the individual aggregates
become entangled. In this way, self-supporting surface
structures such as, for example, webs, plates or moulded bodies
can be produced from expanded graphite.
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5b
In order to stiffen and increase the stability of these
graphite panels or moulded bodies, the expanded
graphite can be mixed with curing binders such as, for
example, resins or plastics, in particular elastomers
or duromers. In order improve the stability of panels
made of expanded graphite, it is particularly suitable
to mix the expanded graphite with thermoplastic and/or
thermosetting plastics which can be introduced into the
expanded graphite for example by impregnation or by
means of a powder method. After the binder mixed with
the expanded graphite has been cured, the graphite
moulded bodies or plates made from these mixtures have
a sufficient stability for the intended application
provided according to the invention. The graphite
panels produced in this way are in particular self-
supporting and can readily be fixed to components such
as ceilings or walls, for example by adhesive bonding
or screwing.
Pure expanded graphite, in the same way as mixtures of
expanded graphite with binders, has a very good thermal
conductivity. The thermal conductivity of a mixture of
expanded graphite with a binder is still very high with
a 50 wt.% binder fraction according to the type of
binder used. Insofar as graphite panels are mentioned
in the following, these are understood as panels which
either consist of pure expanded graphite or a mixture
of expanded graphite with a binder.
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5c
In some embodiments, the fraction of the binder is 5 to 50
weight percent and preferably lies between 8 to 12 weight
percent.
It is also possible to manufacture graphite panels from
mixtures of expanded graphite with phase-change materials (PCM,
phase change materials). For this purpose, common phase-change
materials, for example based on paraffin, wax or salt can be
added during the manufacture of the graphite panels. Such a
graphite panel with a phase-change material can be used in the
temperature control systems according to the invention
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as additional thermal accumulators (latent heat
accumulator) along with the component 5 acting as a
thermal accumulator.
Pipes 9 are embedded in the graphite panel 1 shown in
Figure 1. The pipes 9 are preferably arranged in a
serpentine shape in the interior of the panel 1. Other
laying patterns of the pipes such as, for example, a
spiral-shaped, grid-shaped or meander-shaped
arrangement or an arrangement only in the edge zones of
the panel 1 is feasible. The ends of the pipes 9
running in the panel 1 are connected to a conveying
device for passing a heating or cooling medium (such
as, for example, hot or cold water) through the pipes
9. In order to provide the entire surface 11 of the
component 5 pointing into the room R with elements 10,
a plurality of such elements 10 can be arranged behind
one another or adjacent to one another and fixed on the
surface 11. The ends of the pipes 9 of each element 10
are then connected to the associated ends of the
adjacent elements 10 to form a pipe circuit and the
pipe circuit is coupled to the conveying device for
passage of the heating or cooling medium.
The fixing of the elements 10 is preferably
accomplished by a thermally conducting adhesive 4, by
which means one principal surface 12 of the panel is
adhesively bonded to the surface 11 of the component 5.
As a result of the adhesive bonding, the principal
surface 12 of the panel 1 is in flat thermal contact
with the surface 11 of the thermal accumulator formed
by the component 5, preferably over the entire
principal surface 12.
The other principal surface 13 of the panel 1 can be
provided with a stiffening layer 6 as in the exemplary
embodiment shown in Figure 1. The stiffening layer 6
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can for example comprise a plaster layer or a glued-on
hard cardboard or plasterboard layer. Combinations of
plaster layers and textile materials embedded therein
such as, for example, nets, woven fabrics, knitted
fabrics, crocheted fabrics or the like, are also
possible. As a result of the stiffening layer 6, on the
one hand the stability of the graphite panel 1 can be
increased and on the other hand the principal surface
13 of the panel 1 pointing into the room R can be clad
in a visually attractive manner. The application of a
stiffening layer 6 is particularly appropriate for
panels 1 made of pure expanded graphite (without added
binder).
The pipes 9 running in the panel 1 can be incorporated
during the manufacture of the graphite panel 1. The
pipes 9 preferably comprise pipes made of metal, for
example copper, or plastic pipes, for example made of
polypropylene or cross-linked polyethylene. However
pipes made of metal are to be preferred because of the
better heat transfer. As shown in the exemplary
embodiment in Figure 1, The pipes 9 can be completely
embedded in the panel 1. However, it is also possible
to arrange the pipes 9 so that they end flush with a
principal surface 12 or 13 of the panel 1.
For embedding the pipes 9 in the panel 1, during
manufacture of the panel, the pipes 9 can be laid in
the filling of worm- or concertina-shaped aggregates
and this combination can be pressed in a known manner
by action of pressure (for example by means of rollers
or pressure plates) to form a dimensionally-stable
graphite panel 1. In order to increase the stability of
the panels, one of the aforementioned binders can be
added during the production process. The graphite
panels 1 thus produced with pipes 9 embedded therein
typically have thicknesses between 8 and 50 mm. The
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density of the graphite panels 1 is usually in the
range of 0.01 to 0.5 g/cm3 (depending on the fraction
of added binder). The graphite panels 1 have a thermal
conductivity of 3 to 6 W/mK.
As a result of the good thermal conductivity of the
graphite panel 1, a certain proportion of the thermal
energy stored in a heating or cooling medium passed
through the pipes 9 can initially be passed by heat
conduction from the pipes 9 to the free principal
surface 13 of the panel 1 and released from there by
thermal radiation and free convection to the room R to
be temperature controlled. This release of heat (or
release of cold when a cooling medium is passed through
the pipes) takes place very rapidly with the result
that the room can be heated (or cooled) very rapidly.
Another portion of the thermal energy stored in the
heating or cooling medium is transferred by heat
conduction from the pipes 9 via the heat conducting
panel 1 to the thermal accumulator formed by the
component 5. By this means, the thermal accumulator is
heated (or cooled when a cooling medium is passed
through the pipes). The thermal accumulator can then
release the thus intermediately stored thermal energy
in a time-delayed manner to the room, where the good
thermal conductivity of the panel 1 ensures that this
is accomplished largely free from losses. The heating
(or cooling) of the room R accomplished in this manner
takes place on a longer time scale (of a few hours).
The temperature control system according to the
invention is therefore able to bring the room R to be
temperature controlled to a desired room temperature
both rapidly and also slowly using the thermal
accumulator. Thus for example, at night in summer the
thermal accumulator can be cooled by passing a cooling
medium (for example cold water) through the pipes 9.
During the day the thermal accumulator can then be used
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for cooling the room by means of a time-delayed release
of cold to the room.
In a corresponding manner, in winter during the day the
temperature control system according to the invention
can firstly be heated for instantaneous heating of the
room by passing a heating medium through the pipes. At
the same time the thermal accumulator is loaded with
heat. At night the flow of the heating medium can be
stopped since the time-delayed release of heat from the
loaded thermal accumulator is sufficient to keep the
room at a (lower) room temperature at night.
Figures 2 and 3 show another exemplary embodiment of a
temperature control system according to the invention.
The same or corresponding parts in Figures 2 and 3 are
provided with the same reference numbers as in Figure
1.
In the exemplary embodiment of a device according to
the invention for the temperature control of a room R
shown in Figure 3, a ceiling element 10 is fixed to a
component 5 formed as a concrete ceiling. The component
forms a thermal accumulator with the concrete mass of
the ceiling as accumulator mass. The ceiling element 10
has a frame 2 which is fixed to the surface 11 of the
component 5 pointing into the room R, in particular is
screwed thereon. The frame 2 is configured as a
cassette which is open on one side (i.e. its upper
side). The frame 2 is preferably made of a thermally
conductive material such as, for example a metal sheet.
The frame 2 has a base plate 2a and four side walls 2b
disposed thereon or formed integrally with the base
plate 2a. At least the base plate 2a (and optionally
also the side walls 2b) is formed from a perforated
sheet (i.e. a metal sheet with a perforation). A
graphite panel 1 is inserted in the frame 2. The
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composition of the graphite panel 1 corresponds to the
panel 1 of the exemplary embodiment from Figure 1. As
in this exemplary embodiment pipes 9 are also embedded
in the graphite panel 1 and run there in a serpentine,
grid, spiral or meander shape. The graphite panel 1 is
preferably adhesively bonded flat on the surface 11 of
the component 5 by means of a thermally conductive
adhesive 4. The principal surface 12 of the graphite
plate 1 is therefore expediently in thermal contact
with the surface 11 of the component 5 over its entire
surface. The adhesive layer 4 can however also be
omitted (see below).
A non-woven fabric 3 and a graphite film 15 are
preferably disposed between the base plate 2a of the
frame 2 and the graphite panel 1. The non-woven fabric
3 can for example comprise a glass fibre or a carbon
fibre non-woven. In combination with the perforation of
the base plate 2, the non-woven fabric 3 ensures good
sound absorption of the ceiling element 10. The
graphite film 15 comprises a thin film of expanded
graphite. The thickness of the graphite film 15 is
preferably between 0.05 mm and 3 mm, in particular
between 0.2 and 3 mm.
The non-woven fabric 3 and the graphite film 15
disposed thereon preferably comprises a non-detachable
composite which can be produced for example by
calendering. Such a composite can particularly
expediently be produced from a carbon fibre non-woven
and a graphite film 15 of expanded graphite. When
calendering a thin film of expanded graphite with a
carbon fibre non-woven, the carbon particles of the
non-woven surface and the surface of the graphite film
become entangled with one another so that a firm and
non-detachable composite is formed between the carbon
fibre non-woven 3 and the graphite film 15. It is
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particularly appropriate to use a perforated graphite
film 15. Perforation of the graphite film specifically
increases its flexibility and thereby facilitates the
handling of the film. Since graphite comprises a
brittle material, there is the risk of the film tearing
or breaking when handling thin films of expanded
graphite. This risk can be reduced significantly by
perforation of the graphite film 15.
Figure 2 shows a sectional view of a ceiling element 10
such as can be used in the exemplary embodiment of the
temperature control device according to the invention
shown in Figure 3. As can be seen from Figure 2, the
upper principal surface 12 of the graphite panel 1
projects over the upper edge 2c of the side walls 2b of
the frame 2. When using such a ceiling element 10, the
adhesive bonding of the graphite panel 1 to the surface
11 of the component 5 can be omitted. For fixing the
ceiling element 10 to the component 5, the frame is
specifically screwed onto the component S. When
screwing the frame 2 to the surface 11 of the component
5, the graphite panel 1 is compressed until the
principal surface 12 of the panel 1 ends flush with the
upper edge 2c of the side walls 2b of the frame. The
compression of the graphite panel 1 is made possible by
the deformability of the expanded graphite. The
graphite material of the panel 1 compressed in the
perpendicular direction to the surface 11 is
expediently in thermal contact with the surface 11 over
the entire principal surface 12 after fixing the
ceiling element 10 to the component 5. As a result of
the good deformability of the graphite material of the
panel 1, unevennesses and protrusions in the surface 11
of the component 5 can also be compensated.
The arrangement of the ceiling element 10 or plurality
of adjacent ceiling elements on the surface 11 of the
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component 5 corresponds to the exemplary embodiment of
Figure 1 described above. The mode of operation of the
temperature control device of Figure 3 is the same as
in the exemplary embodiment of Figure 1.
