WO2011080687A2

WO2011080687A2 - Device for extracting heat from a wastewater collector and plant using such devices

Info

Publication number: WO2011080687A2
Application number: PCT/IB2010/056075
Authority: WO
Inventors: Julien Piques; Christophe Anselme
Original assignee: Lyonnaise Des Eaux France
Priority date: 2009-12-30
Filing date: 2010-12-27
Publication date: 2011-07-07
Also published as: WO2011080687A3; FR2954819A1; FR2954819B1

Abstract

The invention relates to a device (D) for extracting heat from a wastewater collector, comprising a heat exchanger (Ea) to be submerged in the wastewater stream and means for establishing a connection between a heat-transfer fluid circuit in the exchanger and heat-transfer fluid inlet and return channels. The invention also includes a system (S) of heat-transfer fluid channels associated with the heat exchanger (Ea), which system is linked to the exchanger.

Description

DEVICE FOR EXTRACTING HEAT IN A WASTEWATER COLLECTOR, AND INSTALLATION USING SUCH DEVICES.

The invention relates to a device for extracting heat in a wastewater collector, comprising a heat exchanger designed to bathe in the wastewater stream, and connection means between a heat transfer fluid circuit provided for in the heat exchanger and the inlet and outlet pipes of the heat transfer fluid.

Devices of this kind are known, in particular according to US 2007/0163762 and allow a recovery of thermal energy from a sewerage network.

The recovery of thermal energy comes from the fact that sanitation pipes convey, in urban and peri-urban areas, waters whose temperature is between 12 ° C and 20 ° C throughout the year. This energy resource is available, continuous and can be used for heating and cooling buildings, via heat pumps. In the same way as for geothermal energy, heat recovery is carried out by means of a heat pump which makes it possible to transfer energy from the waste water of a low temperature level, by cooling on an evaporator, to a higher temperature level of the order of 35 ° C to 65 ° C, by recovery on a condenser.

The thermal potential of wastewater is particularly well suited to collective buildings. The performance of an installation will depend mainly on the flow and temperature of the wastewater.

Although the flow of wastewater is diverted during the heat exchanger and heat transfer pipe installation operations in a wastewater collector, these operations take place under relatively difficult working conditions and require a relatively long time. long. Establishing the connections between each exchanger and the heat transfer fluid network is relatively difficult to achieve. When the heat transport network is installed under the exchangers, the precise location of a leak on the network is not possible. Access to the heat transport network is difficult and requires the disassembly of the exchangers in case of need for intervention on the heat transport network, especially in case of leaks.

The object of the invention is, above all, to provide a device of the kind defined above which allows rapid installation of the exchanger and the heat transfer fluid network, as well as easier maintenance. According to the invention, a device for extracting heat from a wastewater collector comprises a heat exchanger designed to bathe in the wastewater stream, and connection means between a heat transfer fluid circuit provided for in the wastewater stream. heat exchanger and heat transfer fluid supply and return pipes, the exchanger being delimited by two longitudinal rectilinear edges intended to be arranged parallel to the longitudinal direction of the collector, and by two curved edges,

and is characterized in that a system of pipes for heat transfer fluid, associated with the heat exchanger, is articulated on this exchanger, the pipes of the system being parallel to a straight edge of the exchanger.

Advantageously, the system ducts associated with the heat exchanger have the same length as this exchanger. Preferably, the pipe system associated with the heat exchanger is connected to this exchanger by hinges.

The associated pipe system may be prefixed on the exchanger. Thus, the device can be completely prefabricated in the factory. All devices can be of identical sizes, allowing butt jointing. The heat exchanger generally has a shape adapted to match that of the bottom of the collector, and is delimited by two parallel plates bent to the profile of the bottom of the collector, joined along their edges and between which is located the heat transfer fluid circuit of the exchanger, the plates having at least one edge intended to be arranged parallel to the longitudinal direction of the collector; the heat transfer fluid duct system is advantageously articulated on this edge of the plates so that the duct system can be folded into the concavity of the plates for transport, and be deployed for fixing against the wall of the collector during installation. The heat exchanger comprises an inlet pipe and a return pipe of the heat transfer fluid and the pipe system comprises at least one inlet pipe and one return pipe, these pipes being equipped at one end with a pipe of connection advantageously arranged so that it comes opposite the associated pipe of the exchanger when the pipe system is deployed for installation in the manifold. The pipes of the exchanger may be provided at their connecting end with a sliding clamping sleeve which can be clamped on the two pipes.

Preferably, the conduit system has three parallel lines, namely, an inlet pipe, a return pipe, and a pipe for establishing a Tichelman loop. The pipes of the system can be made of plastic, in particular HDPE (high density polyethylene) or stainless steel. The invention also relates to an installation for extracting heat in a wastewater collector with at least two devices as defined above, characterized in that the heat exchangers are placed in the bottom of the collector and juxtaposed, while the Pipe systems are located above the exchangers and attached to the collector wall, with the same function lines of the systems being connected by end sleeves of the pipes.

The pipes of the systems can be made of plastic, in particular HDPE, and the connecting sleeves between adjacent systems pipes are welded, in particular electrowelded.

The invention consists, apart from the arrangements described above, in a number of other arrangements which will be more explicitly discussed below with reference to an embodiment described with reference to the accompanying drawings, but which is in no way limiting. On these drawings: Fig. 1 is a block diagram of an energy recovery plant with heat exchangers juxtaposed and connected in parallel in a heat transport network according to a Tichelman loop. Fig. 2 is a perspective view of a device according to the invention in the transport position, with the pipe system folded in the concavity of the exchanger.

Fig. 3 is a perspective view, from above and from the front, of the device set up in a wastewater collector, partially and schematically shown.

Fig. 4 is a partial perspective view, on a larger scale, of the adjacent ends of two devices before joining the heat transfer fluid piping systems.

Fig. 5 shows, similarly to FIG. 4, the devices juxtaposed with the pipes connected together and, FIG. 6 is a view of an installed device covered by a protective cover.

Referring to Fig. 1 of the drawings, one can see a facility for recovery of thermal energy including heat exchangers E1, E2 ... In juxtaposed, connected in parallel to a heat transfer network in a B loop Tichelman. This loop B comprises a branch 1a, through which cold fluid from a heat pump arrives. The branch 1 extends directly to the exchanger E1 furthest to perform a 180 ° return along a branch 1b which is connected in parallel to the inputs of the various exchangers. A heated fluid line 2 is connected directly in parallel to the exchanger outlets and returns to the heat pump. With such a loop B, the fluid path for the different heat exchangers has the same length, which makes it possible to equalize the pressure drops. The device D according to the invention is illustrated in FIG. 2 and 3; it comprises a heat exchanger Ea intended to bathe in the wastewater stream, and a system S of heat transfer fluid pipes associated with the heat exchanger. heat. The system S is connected to the exchanger Ea, advantageously prefixed and articulated on one side of the exchanger by hinges 3.

The heat exchanger Ea has a shape adapted to match that of the bottom 4 of the manifold H. It consists of two metal plates 5a, 5b, in particular stainless steel, bent to the bottom profile 4 of the manifold H, in a portion of cylindrical surface. The plates 5a, 5b are joined by welding along their edges and a heat transfer fluid circuit 6 is formed in the space between the plates, in particular in the form of baffles. The exchanger Ea is delimited by two longitudinal rectilinear edges 7a, 7b, preferably parallel, intended to be arranged parallel to the longitudinal direction of the collector H, and by two curved edges 8a, 8b, whose concavity is oriented upwards when the exchanger is in place against the bottom of the collector. The exchanger has in its corners holes (not visible), isolated from the circuit 6, for its attachment in the collector.

The system S of pipes is articulated on one of the straight edges 7a, 7b, in particular the edge 7a according to the diagram of FIG. 2 and 3, the hinges 3, for example three in number, being fixed on this edge.

The pipe system S comprises, for each heat exchanger Ea three pipes, namely a pipe 1 a1 corresponding to a part of the branch 1 a (Fig. 1) of the Tichelman loop, a pipe 1 b1 for the arrival of water to be heated corresponding to a portion of the branch 1b of Fig. 1, and a conduit 2.1 for the departure of the heated water corresponding to a portion of the pipe 2 of Fig .1. The three ducts 1 a1, 1 b1, 2.1 are parallel to the rectilinear edge 7a of the exchanger on which they are articulated, and have the same length as the exchanger Ea. By way of non-limiting example, the length of the exchanger Ea may be 3 meters.

The pipes are advantageously made of plastic material, in particular HDPE (high density polyethylene). The pipes are supported by tabs 9, two or three, preferably stainless steel, curved to extend the curvature of the exchanger Ea when deployed as shown in FIG. 2. The lugs 9 may be made with cut metal plates, in particular stainless steel, whose plane is orthogonal to the edge 7a. The legs 9 comprise holes forming housings 10 (FIGS. 4 and 5) for receiving the pipes 1 a1, 1 b1, 2.1. The tabs 9 are fixed and articulated on the exchanger Ea by the hinges 3.

In the transport position of the device D, illustrated in FIG. 2, the system S of pipes is folded into the concavity of the plates 5a, 5b of the exchanger Ea. One or more shims 1 1, in particular formed by a foam plastic block, are provided between the concave wall of the heat exchanger and the system S during transport, and are removed during installation. The heat exchanger Ea comprises a tubing 12 fluid inlet to be heated and a pipe 13 starting the heated fluid. The inlet pipe 1 b1 of the heat transfer fluid in the system S is equipped at one end (FIG 4) with a connecting pipe 14 arranged in such a way that it faces the associated pipe 12 of the pipe. exchanger when the piping system is deployed for installation in the manifold. A connecting pipe 15 is provided in the same manner at one end of the section 2.1 for the heated fluid, for assembly with the pipe 13.

The pipes 12 and 13 are advantageously made of stainless steel tube and are provided, at their connecting end, with a threaded sleeve 16 mounted slidably which can be screwed onto the threaded end of the associated connecting pipe 14,15. These pipes 14 and 15 may be made of plastic, in particular HDPE, and are welded to a sleeve 17 of plastic, itself welded to the corresponding pipe. A bore (not visible) formed in the pipe 1 b1, 2.1 ensures communication between the inside of this pipe and the corresponding pipe 14, 15.

The connection between the pipes 1 a1, 1 b1, 2.1 placed end to end heat exchangers juxtaposed, as shown in FIG. 5, is provided by welded sleeves 18, in particular electrowelded.

Alternatively, the connection between the heat transfer fluid circuit of the heat exchanger Ea and the pipes 1 b1, 2.1 of the system S could be provided by flexible tubes connected in the workshop and provided to move from the folded position to the deployed position, without requiring connection during installation. This being the case, the installation of a device D according to the invention for extracting heat from a wastewater collector, the flow of which has previously been diverted, is carried out in the following manner. The device D, in the folded position illustrated in FIG. 2, is transported and introduced into the manifold H to the determined location.

The heat exchanger Ea is applied and fixed against the bottom of the collector, while the system S of pipes is deployed and applied against the wall of the collector H, on the side. The exchanger Ea is fixed by pins, or the like, through the holes provided in the corners of the exchanger. The legs 9 of the system S are fixed, also by pins, on the wall of the collector.

The connection between the pipes 12, 13, 14, 15 is then made by sliding the sleeves 16 and by tightening them, with the interposition of a joint, on the pipes 15, 16 juxtaposed. The sleeves 18 are engaged on the ends of the pipes 1 a1, 1 b1, 2.1.

Another device D is then juxtaposed and fixed to the collector as illustrated in FIG. 5. The sleeves 18 are moved to cover the adjacent ends of the pipes of the two devices D juxtaposed, then the sleeves 18 are welded, in particular electrowelded, at the six ends of the two systems S of three pipes. This operation is repeated for all devices D of an installation. To provide mechanical protection, the whole is covered with a metal cover 19, in particular stainless steel (Fig. 6). When the installation of the devices D is complete, the waste water flow is again directed to the collector H, and Ea exchangers bathe in this stream.

The device of the invention allows a very rapid deployment of the exchanger and the heat transfer network in the collector. This significantly reduces the duration of the intervention in the collector. The device has many advantages listed below:

the maintenance of the effluent water line, the exchanger being placed at the bottom of the collector;

- saving time on installation; - Increased laying accuracy, assembly being done dry in the workshop and not at the bottom of the collector under difficult conditions;

a reduction in the number of fastening lugs, the assembly being integral;

- a reduction in the risk of leaks from the heat exchanger / heat transfer system, the whole being perfectly aligned in the workshop; the only intervention manifold is to slide and tighten the metal sleeves 16;

- a reduction of the risks of accidents at work due to the reduced duration of intervention;

- optimization of the junction participating in the quality of the guarantee of the delivered product;

- a reduction in the number of potential failures, and therefore a reduction in the number of interventions, leading to less disruption on the network.

Claims

1. Device for extracting heat from a wastewater collector comprising a heat exchanger designed to bathe in the wastewater stream, and connection means between a heat transfer fluid circuit provided in the heat exchanger and pipes for arrival and return of heat transfer fluid, the exchanger (Ea) being delimited by two longitudinal rectilinear edges (7a, 7b) intended to be arranged parallel to the longitudinal direction of the collector H, and by two curved edges (8a, 8b),

characterized in that a system (S) of pipes (1a1, 1b1, 2.1) for heat transfer fluid, associated with the heat exchanger (Ea), is articulated on this exchanger, the pipes of the system (S) being parallel to a straight edge of the exchanger.

2. Device according to claim 1, characterized in that the system pipes (S) associated with the heat exchanger (Ea) have the same length as this exchanger.

3. Device according to claim 2, characterized in that the system (S) of conduits associated with the heat exchanger (Ea) is connected to this exchanger by hinges (3).

4. Device according to any one of the preceding claims, characterized in that the system (S) of pipes associated with the heat exchanger is prefixed on this exchanger.

5. Device according to any one of the preceding claims, wherein the heat exchanger (Ea) has a shape adapted to match that of the bottom (4) of the collector, and is delimited by two parallel plates (5a, 5b) bent in the profile of the bottom of the collector, joined along their edges and between which is located the coolant circuit of the heat exchanger, the plates have at least one edge (7a) intended to be arranged parallel to the longitudinal direction of the collector, characterized in the system (S) of coolant pipe is hinged to that edge (7a) of the plates so that the pipe system can be folded into the concavity of the plates (5a, 5b) for transport, and deployed for fastening against the collector wall during installation.

6. Device according to any one of the preceding claims, characterized in that the heat exchanger (Ea) comprises an inlet pipe (12) and a return pipe (13) of the coolant and the system (S). of pipes comprises at least one inlet pipe (1 b1) and a return pipe (2.1), these pipes being equipped at one end with a connecting pipe (14, 15) arranged in such a way that it comes into view of the associated tubing (12, 13) of the heat exchanger when the pipe system (S) is deployed for installation in the manifold (H).

7. Device according to claim 6, characterized in that the pipes (12, 13) of the exchanger are provided at their connecting end, a clamping sleeve (16) slidably mounted which can clamp on the endsdesdes associated connection pipes (14,15)

8. Device according to any one of the preceding claims, characterized in that the system (S) of pipes comprises three parallel pipes, namely an inlet pipe (1 b1), a return pipe (2.1), and a driving (1 a1) to establish a Tichelman loop.

9. Device according to any one of the preceding claims, characterized in that the pipes of the system (S) are plastic, in particular HDPE.

10. Installation for extracting heat in a wastewater collector with at least two devices according to any one of the preceding claims, characterized in that the heat exchangers (Ea) are placed in the bottom of the collector and juxtaposed, while the pipe systems (S) are located above the heat exchangers and fixed to the wall of the collector (H), the pipes of the same function of the systems being connected by sleeves (18) at the end of the pipes.

1 1. Installation according to claim 10, characterized in that the pipes of the systems (S) are made of plastic material, in particular HDPE, and that the sleeves (18) connecting the adjacent system pipes (S) are welded, in particular electrowelded .