FR2964452A1 - Heat recovery slab for constructing e.g. paved outer surfaces of dwelling in civil engineering field, has cohesive layer made of continuous/discontinuous concrete, bitumen coated material or self-supporting paving block, and resting on bed - Google Patents

Abstract

The slab (1) has a coolant pipe system (5) comprising coolant pipes (4) drowned in a bed (2) that is formed of friable material e.g. gravel, or recycled material. The pipe system is arranged in flush with an upper face (3) of the bed. A cohesive layer (6) is made of continuous or discontinuous concrete, bitumen coated material or self-supporting paving block, and rests on the bed. The bed is formed on a compacted aggregate support layer (7) covered with a film (8) of a thermally sealed barrier. A conductor component is integrated in the bed and/or the cohesive layer. An independent claim is also included for a method for designing a heat recovery slab.

Description

The invention relates to a method for designing a heat recovery slab. The invention relates to the field of civil engineering and more particularly to the construction of external surfaces of technical concrete, coated or paving slabs or the like. In recent years, faced with the problem of fossil energy resources and environmental degradation, more and more systems are being used to use sustainable and non-polluting energies. Of these, solar radiation is undoubtedly the most important source of available energy, and many systems today make it possible to collect radiation for various home heating applications.

Indeed, there are already systems for heating a heat transfer fluid, usually water, from solar energy. Thus, it is known thermal solar panels, consisting of glass plates contiguous to metal pipes, or also tiles also comprising pipes which, through which a heat-transfer liquid, can heat a reserve of water useful for heating a house or a pool. These systems are more effective than the surface of exposure to solar radiation is important. Indeed, the amount of heat produced by these systems is proportional to their surface and the angle of incidence of the rays on the latter. It is understood that in the field of civil construction concrete surfaces, coated or covered with any pavement, constitute an important potential for the collection of solar radiation which, moreover, with a favorable orientation. Thus, it is an object of the present invention to provide a method for the design of such structures for collecting this solar energy for retransmission to an adjacent cold source. In particular, this energy, thus captured, can be used, for example, for heating a dwelling, in particular through a floor equipped with a heat transfer fluid circuit. But it can still be used to heat the volume of water in a pool, just as it can be retransmitted to a water / air heat exchanger to heat or refrigerate, again, a home. It is already known, in particular from WO 9628703, to integrate a heat transfer fluid circuit in a concrete sheet so as to recover the calories through this thermally conductive mass. In this document of the state of the art, it is more particularly referred to concrete blocks incorporating, in a manner embedded in their mass, such a circuit of the heat transfer fluid, these concrete blocks can be multiplied and connected to each other .

If such a known solution actually allows excellent conduction between the agglomerated material of the concrete block and the pipes of the coolant circuit, because of the extensive quality of the contact between these elements, this solution nevertheless has drawbacks that make its implementation expensive. and difficult. In particular, the standards applicable in the field, which govern the sizing rules of concrete surfaces, require, for example, the design of a metal frame when it is intended to drown pipes, this, essentially to contain the removal of the concrete, during the solidification phase. These rules or standards also impose a coating thickness of these pipes according to their diameter. In addition, the characteristics of the reinforcement, in particular, the section of the metal son of the frame is itself a function of the thickness of the slab. It follows that the integration into a slab of a coolant circuit necessarily has the consequence, an increase in the thickness of the slab, so overconsumption of concrete and, of course, reinforcing iron.

Obviously, the time of implementation of such a slab is also more important. Consequently, the solution as proposed in this prior art document WO 96 28703, although conceived for an ecological purpose and for saving energy, loses all its interest when overconsumption is taken into account. energy of materials necessary to comply with the standards imposed in the field. It will be noted that it is still known from document EP-0 049 669, a similar technical solution inducing, obviously, the same disadvantages. In this respect and to return to the implementation of these known solutions, to the drawbacks already mentioned above, it will be further noted that: - in the context of a concrete slab, the casting of concrete is slowed down by the heat transfer conduit network increasing the implementation time and the cost of implementation; the density of the concrete tends, during its implementation, to take away the conduits of the heat transport circuit, thereby distorting their height of coating and only rigid pipes, actually expensive, and firmly fixed to an armature, allow to ensure this implementation of the concrete in the optimal conditions; the large number of mounting brackets required to provide this support for the heat transfer duct network, creates as much potential discontinuity and brittleness in the concrete sheet; - The entire network of pipes, mounting brackets, reinforcing mesh, etc ... are as many obstacles 30 to the casting and the implementation of the concrete that it is difficult to guarantee the absence air pockets, in particular in contact with the heat transport ducts. However, such air pockets can seriously penalize the thermal efficiency of the installation, not to mention that they constitute real areas of weakness by locally reducing the thickness of the pavement.

Specifically, the present invention aims to overcome all the drawbacks of the state of the art by proposing a method of designing a heat recovery slab which, in addition to its ecological interest in energy, is of a lower cost and simplified implementation. To this end, the invention relates to a method of designing a heat recovery slab, characterized in that: - a bed is made of a determined thickness of a friable material, in particular sand; - It is embedded in this bed flush with its upper surface conduits of a heat transfer fluid circuit; - We design on this bed, a layer of cohesive material.

Note, in this regard, that this layer of a cohesive material may be made of concrete, a bituminous mix, but also of any type of pavement made of a reconstituted material, for example free-standing pavers. The advantages which derive from the process according to the invention consist in that by integrating the network of the coolant circuit into the bed of friable material and not into the layer of cohesive material, this may be of lesser thickness by integrating a suitable frame. In fact, under these conditions, this layer of cohesive material does not have to comply with the standards applicable to a tiling integrating, in its thickness, coolant fluid lines. In addition, in an advantageous manner, the method according to the invention allows a simplified implementation. In particular, the establishment of the heat pipe network is greatly facilitated. It can be immobilized by compacting in the bed of friable material and it can possibly be used pipes of lower quality, because not being suspended, they are not subject to sagging under the load of the cohesive layer of the slab.

Of course, when this cohesive layer is made of concrete, the casting operation of this concrete is not penalized by the presence of the heat transfer fluid pipe network and is carried out as a traditional slab with a time of implementation short. Also, the solution according to the invention has a clear advantage of productivity compared to existing solutions. Another advantage of the method according to the invention consists in the possibility of decoupling the functions of each of the layers of the slab in this case, those provided by the bed of friable material functions fulfilled by the cohesive layer. In particular, according to the invention, this cohesive layer can be tinted in a dark color for maximum energy absorption by radiation. This layer, thin because not having a network of integrated ducts within it or without a frame, is a reduced mass compared to current solutions and thus provides a temperature rise faster. As for the lower layer defined by the bed of friable material, this material can be of high conductivity mineral type for optimal transfer of the energy available on the surface to the coolant pipes. Apart from the fact that the solution according to the invention makes it possible to design the cohesive layer in a more homogeneous manner, it is also easier to integrate in this layer, expansion joints which, in the solutions of the state of the art. , must necessarily be performed around the pipes of the coolant network. The solution according to the invention still allows the use of recycled materials, in particular for making the bed of friable material. Other objects and advantages of the present invention will become apparent from the following description relating to an exemplary embodiment given by way of indication and not limitation. The understanding of this description will be facilitated by reference to the figures of the accompanying drawing, in which: FIG. 1 is a schematic and sectional representation of a first embodiment of a slab designed according to the method according to the present invention; invention; Figures 2 and 3 are identical to Figure 1 corresponding to other embodiments of this slab according to the method of the invention. The present invention relates, more particularly, to a method of designing a heat recovery slab 1, various embodiments of which have been illustrated in Figures 1 to 3 of the accompanying drawing. According to this method, according to the invention: - a bed 2 of a determined thickness, made of a friable material, such as sand or the like, is drowned in this bed, flush with the upper face 3 of the latter, pipes 4 of a network 5 of heat transfer fluid; on this bed 2, a cohesive layer 6 of the slab 1 is designed. More particularly, the bed 2 made of friable material 1, 2, 20 may be produced on a support layer 7 of compacted granulate, which may optionally be covered with a film. 8 of a suitable thermo-sealed barrier. This solution is more particularly shown in Figures 1 and 2, knowing that in Figure 3, the support layer 7A is shown in the form of a floor which can be constituted by a concrete slab or the like. Again, between the floor constituting the support layer 7A and the bed of friable material 2 may be interposed such a film 8 of a heat-sealed barrier. To return to the bed 2 and the material that composes it, it may be of mineral type and be in the form of sand and / or gravel, or synthetic type and formed of granules of such material. This material can still be derived from recycling and recovery of construction waste. In particular, the ground materials from demolition sites can be used perfectly for the design of this bed 2 for receiving the network 5 of heat transfer fluid pipes 4. In addition, this friable material making up the bed 2 can be chosen as a function of the desired level of thermal conductivity. Moreover, the thermal conductivity of compacted river sand is greater than that of concrete. Through such a conductive material, the calories, captured by the cohesive layer 6, are capable of being transmitted more easily to the heat transfer fluid through the walls of the pipes 4 corresponding to the network 5. As indicated above, in this bed 2 of friable material, it walnuts these pipes 4 of the heat transfer fluid network 5 so that they are advantageously flush with the upper face 3 of the bed 2 to be in almost direct contact with the cohesive layer 6. Maintaining in this bed 2 of this network 5 of pipe 4 can be provided by simple compaction of the bed 2 and no support for these pipes is ultimately necessary in this case. With regard to the cohesive layer 6, it can, of course, be made of concrete and be in the form of a continuous or discontinuous sheet and made up of several concrete blocks of different or identical sizes with, possibly, interposition of expansion joints. Rather than concrete, this cohesive layer 6 may be in the form of bitumen-based asphalt. It can also be made in the form of a pavement, with self-supporting pavers made of natural or reconstituted stones. Here again, their material will preferably be chosen for its thermally conductive quality. However, the present invention can not be limited to such an embodiment of these blocks. In particular, these can still be made of a synthetic material, which material can, moreover, integrate a conductive component to improve the thermal conductive quality.

As is clear from the above description, the present invention provides real solutions to the problem posed by the state of the art in terms of heat recovery slab.

Thus, this invention facilitates the design of such a slab heat recovery, while being a lower cost. In particular, the method according to the invention makes it possible, in certain cases, to completely get rid of reinforcement in the cohesive layer, which may be of lesser thickness. This cohesive layer is easy to implement, because it does not integrate the network of coolant pipes, not to mention that it gains in homogeneity. Of course, the laying of the coolant pipe network in the bed of friable material is also greatly facilitated knowing that in addition to the bed in question can be designed from recycled materials. In addition, as has already been noted, the absence of the coolant network in the cohesive layer also facilitates the design of the expansion joints at the latter and it is also easier to perform therein. bleeding or cutting without damaging the pipes in the bed of friable material. Although the invention has been described with respect to a particular embodiment, it is understood that it is in no way limited and that various modifications of shapes, materials and combinations thereof can be made. various elements without departing from the scope and spirit of the invention.

Claims (11)

1. slab (1) heat recovery, characterized in that it comprises: - a bed (2) of friable material; - a network (5) of pipes (4) of a heat transfer fluid embedded in this bed (2) flush with the upper face (3) of the latter; - A cohesive layer (6) including bituminous asphalt concrete or paving resting on the bed (2). 2. A method of designing a slab (1) for heat recovery, characterized in that: - a bed (2) is made of friable material; - in this bed (2) is embedded flush with the upper face (3), a network (5) of pipes (4) of a heat transfer fluid; - We design on the bed (2) a cohesive layer (6) of the slab (1). 3. Method according to claim 2, characterized by the fact that it drowns the network (5) of pipes (4) of a heat transfer fluid in the bed (2) by compacting. 4. Method according to claim 2 or 3, characterized in that the bed (2) of friable material is formed on a support layer (7; 7A) with interposition of a film (8) of a thermo-sealed barrier 5. Method according to any one of claims 2 to 4, characterized in that it carries out the bed (2) based on sand. 6. Method according to any one of claims 2 to 5, characterized in that it carries out the bed (2) based on recycled materials. 7. Method according to any one of claims 2 to 6, characterized in that the cohesive layer (6) is continuous or discontinuous concrete. 9 8. Method according to any one of claims 2 to 6, characterized in that the cohesive layer (6) consists of self-supporting pavers. 9. Method according to any one of claims 2 to 6, characterized in that the cohesive layer (6) consists of a bitumen-based mix. 10. Process according to any one of Claims 2 to 9, characterized in that a dye chosen to improve the absorption of solar radiation is integrated in the cohesive layer (6). 11. Method according to any one of claims 2 to 10, characterized in that in the bed (2) and / or the cohesive layer (6), includes a conductive component.