Patent Application
20130333860
The present invention relates to thermal energy management with respect to a civil engineering structure.
A civil engineering structure is conventionally provided with thermal energy by specific means, which are added to the structure precisely for that purpose. Those means include heaters when the temperature inside the structure must be increased and/or air-conditioners when the temperature inside the structure must be decreased.
More recently, it has been proposed to take benefit from the thermal energy available in an element external to the structure and to transfer it inside the structure. As an example, geothermal technique captures calories naturally stored in the soil at low depth as a result of solar energy absorption or at higher depth as a result of thermal activity of the Earth, and transforms them into a continuous and instantaneous heating solution inside e.g. a house by means of a heat pump.
Such technique may not be adapted however when the structure to be heated or cooled is not a house but a much larger civil engineering structure, such as a stadium, a building, or other. Particularly such structures are not in need of continuous heating or cooling, but only on certain occasions (e.g. matches or shows). This is because the debit flow of calories captured from the soil may then be in insufficient amount with respect to the volume to be regulated in temperature in short period of time.
Moreover, using elements external to the structure to get thermal energy may lead to the construction of a complex, heavy and costly network of geothermic probes, possibly up to long distance from the structure itself. Removal of such network would also represent a complex task.
So there is a need to improve the heating or cooling with respect to a structure, by alleviating at least in part some or all the above drawbacks.
The invention thus proposes a structural element for a civil engineering structure, arranged for transitorily storing and using in a deferred manner thermal energy. The structural element is provided with:
Such structural element, which is (or is intended to become) part of a civil engineering structure, is the one element that stores thermal energy transitorily. The invention thus takes benefit from the structure itself to generate heat or coolness. Building a long and complex network of geothermic probes outside the structure may thus be avoided. This also helps demounting the structure if needed, as only limited portions of the heat exchangers may remain in place after removal of the structural element.
Moreover, the two different sets of heat exchangers used in cooperation with the structural element allow to bring the structural element to a determined temperature, in a process which may be continuous in time, and then, only when necessary, to use the thermal energy so transitorily stored in the structural element to increase or decrease the temperature inside the structure. Due to its thermal inertia, the structural element is thus used as a temporary heat or coolness buffer.
According to optional features that may be combined in any possible way:
The invention also proposes a civil engineering structure comprising at least one structural element for transitorily storing and using in a deferred manner thermal energy as mentioned above, such as a stadium structure.
The invention also proposes a method for transitorily storing and using in a deferred manner thermal energy in a structural element as mentioned above. This method comprises:
The invention also proposes a method for building a structural element for transitorily storing and using in a deferred manner thermal energy as mentioned above. This method comprises:
The preferred features of the above aspects which are indicated by the dependent claims may be combined as appropriate, and may be combined with any of the above aspects of the invention, as would be apparent to a person skilled in the art.
An aspect of the present invention relates to a structural element for a civil engineering structure. Any structural element for any type of engineering structure may be envisaged. In the following, an element for a stadium structure will be more particularly considered, without limiting in any way the general scope of the invention. Other examples of structures to which the invention may apply include e.g. a greenhouse, a building, and/or other.
Such structural element 3 can be made of any type of natural and/or artificial material. As an example, it may comprise soil or earth, possibly stabilized. Alternatively or in addition, it may comprise concrete, possibly recycled, steel and/or other.
The structural element 3 is arranged for transitorily storing and using in a deferred manner thermal energy, i.e. heat or coolness.
To do so, the structural element 3 is provided with two different sets of at least one heat exchanger each.
In the illustrated example, the heat or coolness source S includes subsoil above which the structural element 3 is located. Alternatively or in addition, the heat or coolness source S may include other subsoil, e.g. located further away and/or not below the structural element 3. Alternatively or in addition, the heat or coolness source S may include an aquatic medium such as a sea, groundwater and/or other, in which an end of the heat exchangers of the first set 1 are immersed.
Other variants for the heat or coolness source S may be envisaged alternatively or in addition, as will be apparent to one skilled in the art. In an advantageous example, S may be a heat source and include a set of at least one solar probe, so as to take benefit from the heat generated from the sun.
Note that different sources may be used depending on whether heat or coolness is sought. Alternatively, a single source may be used as a heat source or a coolness source, depending e.g. on the external temperature. For instance, the subsoil S lying below the structural element 3 may be used as a heat source in winter when the air temperature is low, while it may be used as a coolness source in summer when the air temperature is high.
In the example of
In the bottom part, the tubes may be closed so that the heat exchangers work in closed loop. This is adapted for example when the heat or coolness source S consists in subsoil. Alternatively, the tubes may be open so that the heat exchangers work in open loop. This is adapted for example when the heat or coolness source S includes an aquatic medium. In the bottom part, the tubes may be substantially parallel and/or of similar length as represented in
In the top part, the heat exchangers of the first set 1 may be closed. They may be arranged in superposed layers as represented in
Note that the geometry of the first set 1 of heat exchangers may take various forms and the above-described example should be in no way interpreted as limiting. For example, the heat exchangers may not be vertical and/or parallel in their bottom part. They may not be horizontal and/or parallel in their top part. Also, they may not have two different portions. As another non-limiting example, the first set 1 of heat exchangers could consist only in a series of vertical tubes extending from the subsoil S into the structural element 3. At least some of the heat exchangers of the first set 1 may not have a rectilinear course.
At least some of the first set 1 of heat exchangers may be located at least in part in the foundation of the civil engineering structure, e.g. the stadium, in which it is intended to cooperate.
In any case, thermal energy is transferred by means of the first set 1 of heat exchangers from the heat or coolness source S to the structural element 3 where it is transitorily stored.
This transfer may result from natural circulation of a heat transfer fluid within the heat exchangers of the first set 1.
Advantageously, the first set 1 of heat exchangers may make use of an additional device 4 to facilitate the thermal energy transfer as shown in
Alternatively or in addition, the device 4 may comprise at least one heat pump. Such heat pump, which may comprise at least a condenser, an expansion valve, an evaporator and a compressor as is conventional, has the effect of offsetting the temperature in the first set 1 of heat exchangers and the temperature in the heat or coolness source S, as will be easily understood by one skilled in the art. Compared to a simple pump, the use of a heat pump allows increasing the heat exchanges between the heat or coolness source S and the structural element 3. The structural element 3 can thus be made colder or hotter depending on the sought result.
Note that the position and the number of simple pump(s) and/or heat pump(s) may be various and different from the example shown for illustrative purpose in
In the attached figures, hot and cold portions of the heat exchangers have been schematically represented with thick and thin lines respectively. It should be understood however that this representation is only for illustrating the direction of the transfer of thermal energy, and should not be interpreted as a strict delimitation.
In the example shown in
The first set 1 of heat exchangers may be maintained active on a determined period of time, which may be long, such as several days, weeks or months. It may be maintained active continuously or quasi-continuously. This may ensure that the structural element 3 reaches a determined temperature and stores a determined amount of thermal energy.
The thermal energy so transitorily stored within the structural element 3, and thus within the civil engineering structure in which the structural element 3 takes part, will then be transferred at least in part to at least one entity external to the structural element 3.
The entity in question may include another structural element for the civil engineering structure in which the structural element 3 takes part. For example, when talking of a stadium structure, the entity may include benches. Alternatively or in addition, the entity may include air adjacent to the structural element 3. For example, when talking of a stadium structure, the entity may include air adjacent to benches which are supported by the structural element 3, or more generally air located at or around the center of the stadium. Many other types of entities may be envisaged, depending on the application, as will be apparent to one skilled in the art.
Transferring at least part of the thermal energy transitorily stored in the structural element 3 to at least one entity is made by activating a second set of at least one heat exchanger extending between the structural element 3 and said entity.
The activation of the second set of at least one heat exchanger may result from the fact that a determined criterion is satisfied. Any possible criterion may be envisaged in this regard. As an example, the criterion may be related to the usage of the civil engineering structure in which the structural element 3 takes part. When talking of a stadium, such criterion may include the immediate or coming (e.g. in a few hours) start of a match game. Other occasions, such as shows, periodical events, and/or other may also be the basis for a determined criterion being satisfied. Dynamic parameters such as temperatures, e.g. of the air, of the structural element 3, of the entity and/or of other element(s), may be taken into account in the considered criterion.
The detection of a determined criterion being satisfied and/or the resulting activation of the second set of at least one heat exchanger may be totally automatic, totally manual or a combination of automatic and manual operations.
Because the thermal energy transitorily stored in the structural element 3 is transferred at least partly to the entity only upon activation of the second set of at least one heat exchanger, that is possibly long after it has started being stored in the structural element 3, it may be seen as a deferred use of such thermal energy. This is contrast with prior techniques, in which only one set of heat exchangers is needed and/or the thermal energy obtained via this set is used directly and without delay.
In the example of
In this case, the incoming air is conducted from outside the structural element 3 into the heat exchangers of the second set 2a and throughout the structural element 3. It is thus refreshed by contact of the heat exchangers with the structural element 3 storing coolness. The refreshed air leaves the heat exchangers of the second set 2a and it mixes hot ambient air adjacent to the structural element 3.
In order to be conducted within the heat exchangers of the second set 2a and throughout the structural element 3, the air may be pulsed with conventional pulsing means, such as fans. Alternatively or in addition, the air may be simply sucked by a natural convective air flow organized within the civil engineering structure. In case of a stadium, the air may indeed flow from the outside to the inside of the stadium, e.g. by escaping through a hole in the roof of the stadium.
By virtue of such arrangement, spectators sitting on benches and/or players standing on a playing field of the stadium may be refreshed, as they receive refreshed air.
As shown in
In the example of
The second set 2b of heat exchangers may include tubes filled with a heat transfer fluid, e.g. in closed loop.
Like for the first set 1 of heat exchangers mentioned above, one or several simple pumps or heat pumps 10 may be used to favour the heat exchanges between the structural element 3 and the benches (or any other suitable entity). Those pumps 10 may be used to activate or deactivate the second set 2b of heat exchangers.
With this arrangement, spectators sitting on the benches supported by the structural element 3 and/or players standing on a playing field adjacent to the structural element 3 may be refreshed by contact or proximity with the refreshed benches and/or playing field.
In
This structural element 3 of
As shown in
Moreover, one or several reinforcement members extending within the backfill may be connected to this facing. Alternatively or in addition, one or several reinforcement members may be disconnected from this facing. The reinforcement members may take various forms and use various materials, such as metal (for example galvanized steel), synthetic (for example based on polyester fibers), a combination thereof, etc. They may be placed in the backfill with a density that is dependent on the stresses that might be exerted on the structure, as will be apparent to one skilled in the art.
The facing 6 may be made of prefabricated concrete elements, e.g. in the form of slabs or blocks, juxtaposed to cover the front face of the structure. It may be built in situ by pouring concrete or a special cement.
Advantageously, the facing 6 may be separated from the backfill by at least one location (and possibly on all its internal surface) with a thermal insulation material 7 such as expanded polystyrene, mineral fibres and/or other. By doing so, it is avoided that too much of the thermal energy transitorily stored in the structural element 3 escapes through the facing 6. When heat exchangers must go out of the structural element, corresponding limited holes may be arranged in the facing 6 and the insulation material 7 for this purpose.
In an advantageous arrangement, at least part of the first and/or second set of at least one heat exchanger may simultaneously play the role of reinforcement member(s) for the stabilized structural element 3. In this case, at least one heat exchanger of the first and/or second set of at least one heat exchanger may be connected to the facing 6. In particular, horizontal parts of heat exchangers of the first set 1 and/or the second set 2a-2b as described above may be additionally used as reinforcement members for the stabilized structural element 3. It is thus avoided to provide heat exchangers and reinforcement members independently, which reduces both the time required to build the structure and its cost.
When the structural element 3 is part of stadium, as assumed above, benches 5 may mark another boundary thereof, opposite to the facing 6. Such benches 5 may have the same composition as the structural element 3, for example stabilized soil or earth. Alternatively or in addition, the benches 5 may use different materials, such as wood, cement, concrete and/or other.
Various elements may be placed at least partly on or in the structural element 3. For example, access stairs, tiers and/or railings may be placed on the backfill. Cubicles, technical premises, access tunnels and/or shops may be placed inside the backfill. Those elements could be cooled or heated as desired, by means of the above-described first and/or second set of at least one heat exchanger.
As shown in
Many other arrangements for a structural element may be envisaged within the framework of the present invention, as will be apparent to one skilled in the art.
Other elements may be associated with the structural element 13. For example, benches 15 are supported by the structural element 13. A playing field 17 is located next to the structural element 13. Reinforcements may be placed within the structural element 13, etc.
According to an embodiment, the first set 11 of heat exchanger corresponds to the one described previously, in particular said first set of heat exchanger comprises a tube arranged for conducting a heat transfer fluid in the heat or coolness source and a tube arranged for conducting a heat transfer fluid in the structural element 13.
The second set of heat exchanger may also comprise a tube arranged for conducting a heat transfer fluid in the structural element 13.
According to a particular embodiment of the invention, the first and second sets of heat exchangers have part of said tube arranged for conducting a heat transfer fluid in the structural element in common.
In the embodiment represented on
According to such embodiments of the invention, the heat exchanger may be arranged in layers, for example they may be included in substantially horizontal or vertical planes respectively. Alternatively or in addition, each heat exchanger may include several branches.
The geometry of the heat exchangers may take various forms and the above-described examples should be in no way interpreted as limiting. For example, the heat exchangers may not be vertical and/or parallel. They may not be horizontal and/or parallel. Also, they may not have two different portions. At least some of the heat exchangers of the first and second sets may not have a rectilinear course.
The thermal reservoir 30 is arranged so as to be able to take the lateral and vertical pressure applied by the structure and store and release thermal energy. For example the thermal reservoir 30 may be delimited by a liner filed with soil, earth, sand or rocks.
The tubes of the first and second heat exchanger are closed so that the heat exchangers work in closed loop.
For example, the first heat exchanger may have a hot fluid circulate trough the tubes of the first heat exchanger in the thermal reservoir so as to heat up the material comprised in the thermal reservoir. According to this embodiment, the heat transfer fluid remains in the tubes and does not come in contact with the material comprised in the thermal reservoir.
When required one may have a second heat transfer fluid circulate in the tubes of the second heat exchanger in the thermal reservoir. The second heat transfer fluid is heated by the porous material trough the tubes.
According to such embodiment, no fluid exchange takes place between the first and second heat exchanger and the thermal reservoir. Such heat transfer may also apply with a cold source.
Advantageously, the structure element 13 according to the embodiment of
According to the embodiment represented on FIG. 8., the thermal reservoir 30 is filed with a porous material arranged so as to be able to take the lateral and vertical pressure applied by the structure. For example the thermal reservoir 30 may be filed with soil or earth or stones or gravel or rocks.
A good porous material should be strong, hard-wearing, stable, drainable, resistant to deformation, easily available, and reasonably cheap to purchase.
For example the porous material is made of crushed natural rock with particles between 28 mm and 50 mm in diameter. A high proportion of particles finer than this would reduce its drainage properties, and a high proportion of larger particles would result in the load being distributed improperly. Angular stones are preferable to naturally rounded ones, as angular stones interlock with each other.
Granite is one of the best materials in this regard. It is also possible to use the slag produced by blast furnaces. In generally material used for track ballast is suitable as porous material.
The tubes of the first and second heat exchangers are open so as to have the heat transfer fluid circulate trough the thermal reservoir trough the porous material.
For example, the first heat exchanger may have a hot fluid circulate trough the thermal reservoir so as to heat up the porous material comprised in the thermal reservoir.
When required one may have a second heat transfer fluid circulate trough the thermal reservoir using the second heat exchanger. The second heat transfer fluid being heated by the porous material.
Such heat transfer may also apply with a cold source.
Advantageously, the structure element 13 according to the embodiment of
One skilled in the art will appreciate that other arrangements may be envisaged. Those arrangements may be adapted depending on the nature and usage of the civil engineering structure considered.
Building the structural element 3 or 13 described above may be performed by:
Other buildings methods may be carried out alternatively or in addition, as will be apparent to one skilled in the art.
Note that demounting or removing such structural element 3 or 13 is not too complex a task. For example, when the structural element is mainly made of earth, the latter may be taken away little by little. The heat exchangers of the second set and possibly of the first set (and/or other elements), cleared by this operation, may be removed in turn. Most or all of those elements may be reused later on to build a new structure at the same location or elsewhere.
| Number | Date | Country | Kind |
|---|---|---|---|
| 11305168.4 | Feb 2011 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2011/071965 | 12/6/2011 | WO | 00 | 8/19/2013 |
