WO2018127528A2

WO2018127528A2 - Device and method for recovering thermal energy from a flow, with optimised cleaning

Info

Publication number: WO2018127528A2
Application number: PCT/EP2018/050171
Authority: WO
Inventors: Théo BERGON; Hugo Durou; Thomas Ricou
Original assignee: Energy Harvesting Tech
Priority date: 2017-01-04
Filing date: 2018-01-04
Publication date: 2018-07-12
Also published as: FR3061546A1; WO2018127528A3; FR3061546B1

Abstract

The invention relates to a thermal energy recovery device with optimised cleaning, comprising a heat exchanger (130) through which two separate fluid flows pass, said heat exchanger being equipped with first inlet (131) and outlet (132) ports and second inlet (133) and outlet (134) ports. A network of hydraulic pipes (10), connected to the exchanger (130), comprises: an inlet pipe (180) for the first fluid, connected (141) to the first inlet port (131); an overflow pipe (150) connected (141) to the inlet pipe (180) and connected (171) to a sewer collection pipe (170); and a supply pipe (160) for the cold sanitary bleed water, connected (161) to the first outlet port (132). According to the invention, the connection (161) of the cold sanitary water supply pipe (160) comprises a means (190) for reducing the flow area of the cold sanitary bleed water (202), said means being located at the inlet of a zone (163) for connecting to the sewer collection pipe (170). A discharge valve, disposed upstream of the reduction means (190), is designed to allow the temporary passage of the flow of cold water (202) towards the first outlet port (132).

Description

DEVICE AND METHOD FOR RECOVERING THERMAL ENERGY FROM AN OPTIMIZED CLEANING FLOW

DESCRIPTION

FIELD OF THE INVENTION

The present invention relates to a device for recovering the thermal energy of a fluid flow cleaning optimized by a purge flow against the current, and a cleaning optimization process of this device. The device is more particularly, but not exclusively, adapted to the heat recovery of a gray water flow from domestic or collective sanitary facilities.

By "greywater" is meant in the context of the present invention the water that comes from domestic uses such as showers, sinks or baths of bathrooms, kitchen sinks, dishwashers and appliances. washing machines. Greywater is generally laden with pollutants, such as food residues, greases, oils, cleaning agents, fibrous materials such as hair or textile fibers, etc.

STATE OF THE ART

A gray water heat recovery device collected by a receiver is known from the prior art, in particular from the applicant's patent application EP 2 820 354, and illustrated in FIGS. 1 and 2. prior art recovers heat from gray water collected by a receiver, for example the shower tray, by means of a plate heat exchanger 130. In the nominal mode illustrated in Figure 1, gray water collected by the receiver cross (flow 100) the plate heat exchanger 130 into which they enter through a first port 131 and exit through a first output port 132 in a sewage collection line 170. In parallel, sanitary cold water for supplying a receiver, for example the shower, through the exchanger thermal plate 130 in which it enters through a second inlet port 133 and out through a second outlet port 134. Through the plate heat exchanger 130, the cold water is warmed by the flow of greywater .

The recovery device also includes hydraulic facilities for directly diverting the flow of gray water to the sewage collection line 170 when the plate heat exchanger 130 is clogged. Thus, an overflow line 150 is connected bypass to the first port of between 131, and directs the gray water flow 101 to the sewer collection line 170.

This recovery device also comprises hydraulic arrangements intended, in cleaning mode, to dislodge a plug causing obstruction of the plate heat exchanger 130. To do this, in the example of Figures 1 and 2, the recovery device comprises a first valve 142, called a pinch valve, with hydraulic control, placed on the sewage collection line 170 and putting the first outlet 132 of the exchanger 130 in communication with the sewer, when is busy.

A second valve (not shown), driven in a non-hydraulic manner, is placed on a supply line 160 of the sanitary cold water, mounted as a bypass of the collection pipe to the sewer 170 and upstream of the pinch valve 142. The second valve allows the passage of a stream of sanitary cold water, when it is passing.

During nominal operation (see Figure 1), the sleeve valve 142 is passing and the second valve is closed. Gray water collected at the receiver (flow 100) passes through the plate heat exchanger 130 before entering the sewer and heat up the flow of sanitary cold water to the receiver.

[0008] FIG. 2 illustrates the cleaning mode, or purge mode, when the plate heat exchanger 130 is plugged. During cleaning, the sleeve valve 142 is closed and the second valve is passing. Sanitary cold water, at the pressure of the network, is sent into the plate heat exchanger 130 at the first outlet port 132 thereof, causing a flow 102 opposite to that of the normal flow of greywater ( flow 100) in said plate heat exchanger 130. Thus, the stream of sanitary cold water passing through the plate heat exchanger 130 from its first output port 132 to its first input port 131 flows into the sewer by the sewage collection line 170 via the overflow line 150 (stream 102).

This circulation in the opposite direction and under the load of the pressure of the sanitary cold water network, allows to dislodge any plug obstructing the first input port 131 of the plate heat exchanger 130 and to send said plug in the sewer. Thus, the stream of sanitary cold water passing through the plate heat exchanger 130 in the opposite direction of the nominal flow is a real cleaning flow.

Such a recovery device offers interesting thermal performance.

However, the sleeve valve used represents a significant increase in the complexity of the device. It also has significant dimensions and is therefore very voluminous in the final device. Finally, elements generating pressure drops - in order to maintain the pressure necessary to close this valve - strongly limit the flow of the purge and therefore its effectiveness.

SUMMARY OF THE INVENTION

The present invention aims to overcome the disadvantages of the prior art. For this purpose, the invention provides for a suitable reduction of discharging a purge water flow at an adjusted distance from the inlet of a connection zone of the heat exchanger to the sewage collection pipe.

More specifically, the subject of the present invention is a device for recovering the thermal energy of an optimized cleaning fluid flow, comprising a plate heat exchanger traversed by a first and a second separate fluid stream, said exchanger being provided with first input and output ports of the first fluid and second input and output ports of the second fluid.

A network of hydraulic pipes is connected to said heat exchanger and comprises an inlet pipe of the first fluid in hydraulic communication with said first inlet port, an overflow pipe in hydraulic communication on the one hand with the pipe of arrival and secondly with a sewage collection pipe, and a sanitary cold water supply pipe purge in hydraulic communication with the first port of exit.

In this device, the hydraulic communication of the supply line of the sanitary cold water comprises, at the entrance of a connection zone with the sewer collection line, a passage section reduction means a purge cold water flow in said supply pipe, as well as a purge valve, arranged upstream of the reduction means in the nominal direction of flow of the sanitary cold water flow and configured to temporarily allow the flow of cold water to the first exit port.

According to particularly advantageous embodiments:

the reduction means comprises a diameter reducing tip of the passage section of the cold water flow forming a through-orifice with a fixed axis with respect to a longitudinal axis defined by the purge supply line;

the reduction tip is a ring fixed in the pipe supply of cold sanitary water by a selected connection between brazing, crimping, gluing and screwing;

the purge valve is an electrically controlled valve;

the hydraulic communications are three-way couplings chosen between a T-piece, a 45 and 67 ° panty connection, and a Y-fitting;

on the one hand, the arrival lines of the first fluid and overflow and, on the other hand, the purge supply lines and the first outlet port are in the extension of one another.

The invention also relates to a cleaning optimization method of the device defined above. This method consists in optimizing a purge flow rate by determining a compromise value of the inside diameter of the reduction means between at least one higher value, which increases the flow rate of the purge flow by reducing the pressure drops, and at least a lower value which generates a higher sanitary cold water jet speed and then increases the driving force of this jet, and by adjusting the jet distance so that the sanitary cold water jet is directed, at the outlet reduction means, to the first output port.

According to a preferred embodiment, the choice of the inside diameter of the reduction nozzle and the jet length is guided by the measurement of the pressure losses created by the jet and the purge flow, the flow rate. purge rate being the flow of water through the countercurrent exchanger from its first out port to its first port of entry and evacuating through the overflow line.

PRESENTATION OF FIGURES

Other advantages, aspects and features of the invention will appear on reading the detailed description which follows, with reference to the appended figures which represent, respectively:

- Figure 1, already commented, an embodiment of a recovery device of the prior art in a perspective view, operating in heat recovery mode greywater;

- Figure 2, already commented, the embodiment of Figure 1 operating in cleaning mode;

- Figure 3, in a perspective view, an embodiment of a recovery device object of the invention operating in gray water heat recovery mode said nominal mode;

- Figure 4, in a perspective view, the embodiment of Figure 3 operating in clogging mode;

FIG. 5, in a perspective view, the embodiment of FIG. 3 operating in cleaning mode, and

FIGS. 6a and 6b, in cross-sectional and overall cross-sectional views respectively, a three-way tee connection connected to a first output port of the plate heat exchanger, when the recovery device according to the invention operates. in cleaning mode.

DETAILED DESCRIPTION

Referring to the perspective views of Figures 3 to 5, according to a non-limiting embodiment of the invention, a device 1 for recovering the thermal energy of a wastewater flow comprises the heat exchanger to plates 130 and a network of hydraulic lines 10 connected to this exchanger 130.

The plate heat exchanger 130 comprises, in a conventional manner per se, plates 135 (see FIG. 6) which favor the creation of a turbulent flow inside the latter, thus limiting the risks of greasy deposit or debris in said exchanger.

In nominal mode, the hydraulic pipe network 10 allows the plate heat exchanger 130 to be traversed by two fluid flows, a greywater flow and a stream of sanitary cold water at the pressure of the network. .

Greywater collected by a receiver, for example a shower tray, pass through the plate heat exchanger 130 in which they enter through a first inlet port 131 and out through a first output port 132. In parallel, sanitary cold water at the pressure of the network, intended to supply at least one receiver, for example a shower, passes through the plate heat exchanger in which it enters through a second input port 133 and out of a second output port 134. By crossing the heat exchanger to plates, the sanitary cold water is warmed by the flow of gray water. The two streams do not mingle with each other and are counter-current to each other.

The first input port 131 is in hydraulic communication with an inlet pipe 140. Said inlet pipe is intended to be connected with a gray water inlet pipe 180, itself intended to be hydraulic communication with the receiver. The inlet pipe 140 is on the other hand hydraulically connected with an overflow pipe 150.

In the non-limiting example of Figures 3 to 5, the gray water inlet pipe 180 and the overflow pipe 150 are mounted in series. The inlet pipe 140 is mounted as a by-pass of the gray water inlet pipe 180 and the overflow pipe 150. The gray water inlet pipe 180 is preferably arranged at a height with respect to the heat exchanger Thus, the wastewater flowing in a gravity flow, they always take the most direct path and flows into the inlet pipe 140 rather than the overflow pipe 150, nominal operation. Said bypass is realized by means of a first three-way connection 141.

An example of a first three-way connection is illustrated and described here in the case of a 45 ° panty connection. The shape of the derivation is not limited to that described and illustrated. Thus, it is possible to alternatively use a tee fitting, a 67 ° pan fitting, a Y-fitting or any other three-way connection.

In the example of the 45 ° panties connection, the waste water inlet pipe 180 and the overflow pipe 150 are in the extension of one another. This overflow line 150 is in hydraulic communication with the sewage collection line 170.

A second three-way connector 171 connects the overflow line 150 and the collection line to the sewer 170. An example of a second three-way connection is illustrated and described here in the case of a tee fitting. The shape of the derivation is not limited to that described and illustrated. Thus, it is possible to alternately use a 45 ° panties connection, a 67 ° panties connection, a Y connection or any other three-way connection.

The first output port 132 is in hydraulic communication with the supply pipe of the sanitary cold water, at the pressure of the network, said purge pipe 160 and the sewage collection pipe 170 is mounted in derivation of this purge line 160.

Said derivation is carried out by means of a third three-way connection 161. An example of a third three-way connector 161 is illustrated and described here in the case of a tee fitting. The shape of the derivation is not limited to that described and illustrated. Thus, it is possible to alternately use a 45 ° panties connection, a 67 ° panties connection, a Y connection or any other three-way connection.

In the example of the bypass fitting Tee 161, the purge pipe 160 is in the extension of the first output port 132 of the plate heat exchanger 130, vis-à-vis this first port of exit 132.

A pilot purge valve (not shown) is mounted on the purge pipe 160 upstream of the T-branch 161, when it is placed in the nominal direction of the flow of a stream of water. Sanitary cold 202 (see Figure 5).

The purge valve is configured to prohibit or allow temporarily passing the flow of cold water sanitary towards the first output port 132. The purge valve is normally closed. In the closed position, it prevents the passage of the flow of cold water sanitary network pressure in the purge pipe 160, towards the first output port 132. In open position said passerby, it allows the passage of the flow of sanitary cold water at the mains pressure in the purge line 160, towards the first outlet port 132.

[0034] Preferably, the purge valve is electrically controlled. In an exemplary embodiment, the purge valve is a solenoid valve.

The perspective view of Figure 3 illustrates an example of recovery device according to the invention operating in the nominal mode of heat recovery gray water. The greywater flowing in a gravity flow, they always take the most direct path and have the least pressure drop between one point and another.

In nominal operation, the purge valve is in the closed position. The greywater flow 200 passes through the plate heat exchanger 130 from the greywater inlet pipe 180 connected to the receiver and then through the inlet pipe 140. The greywater flow 200 then passes through the plate heat exchanger 130, from the first input port 131 to the first output port 132, then takes the collection line to the sewer 170. Simultaneously, the domestic cold water circulates in the heat exchanger at plates 130, via the second inlet ports 133 and 134 exit, and reemerged warmed.

In the event of clogging of the plate heat exchanger 130, as illustrated by the "clogging" mode of FIG. 4, the entry into said plate heat exchanger, via the first input port 131, does not occur. is not the most direct path for the flow 201 of greywater from the recipient, due to the existence of the pressure drop due to clogging. Thus, the greywater stream 201 directly takes the overflow line 150 to join the sewage collection line 170 without going through the plate heat exchanger 130.

In the cleaning mode or purge mode as illustrated in FIG. 5, the purge valve is open and the stream 202 of pressurized cold water flows along the purge pipe 160 to unclog the water. Plate heat exchanger 130. When passing through a reduction nozzle 190 (see FIG. 6), the jet created and directed towards the first outlet port 132 drives the stream 202 of sanitary cold water - called cleaning or purging water. in the plate heat exchanger 130, without substantially deviating into the sewage collection pipe 170.

Thus, the cleaning flow enters the plate heat exchanger 130 through its first output port 132 and undergoes a pressure drop at the passage of the plate heat exchanger 130 that it de-colmate, of so that leaving said plate heat exchanger, by its first inlet port 131, the pressure of said cleaning flow is not sufficient for it to be able to go up the sewage inlet pipe 180 to recipient. Thus, the cleaning flow takes the most direct path and passes through the overflow line 150 to join the collection line to the sewer 170.

The purge pipe 160 comprises, as shown in the sectional views of Figure 6a (overall view) and 6b (enlarged view), the reduction tip 190 of the passage section of the sanitary cold water flow secured in the tee fitting 161 of said purge line 160.

When placed in the nominal direction of the flow of the cold water flow 202 (see Figure 5), the reduction tip 190 is mounted on an end portion 162 of the fitting 161 upstream of the connection 163 with the collection pipe to the sewer 170 and downstream of the connection to the purge pipe 160, that is to say at the inlet of said connection 163 in the direction of sanitary cold water flow 202 in cleaning mode (see Figure 5).

The reduction tip 190 has an inside diameter dp of passage section of a stream of the cold water flow 202 lower than the passage section of this sanitary cold water stream 202 at the first output port 132 of inner diameter dr.

FIG. 6a also illustrates the partial sectional view of the plate heat exchanger 130 with the first exit port 132 of this exchanger 130, to show the evolution of the sanitary cold water flow 202 coming from the pipe purge 160 to the first exit port 132 and the plate heat exchanger 130.

For a given power level of the sanitary water distribution network, the purge flow is optimized by determining a compromise value of the inside diameter dp of the endpiece 190 relative to the inside diameter dr of the first output port 132. Purge flow rate means the flow rate through the plate heat exchanger 130 against the current and discharging through the overflow line 150.

Thus, for a given jet distance "L" between the reduction means 190 and the first output port 132, a compromise is first determined to set the value of the tip diameter dp (see Figure 6b). ): higher values of dp increase the flow rate of the purge stream 202 by reducing the pressure drops while limiting the direct recirculation to the collection pipe to the sewer 170 through the occupation of a large part of the section the outlet port 132 of the exchanger 130 by the sanitary cold water jet 203, while lower values of the tip diameter dp generate an increased jet speed 203, and therefore a higher kinetic driving force, limiting also the direct recirculation to the sewer collection line 170.

The jet distance "L" between the reduction nozzle 190 and the first output port 132 is then adjusted so that the sanitary water jet 203 is directed at the outlet of the reduction tip 190 - when the purge valve is passing - to the first output port 132 for a length sufficient to exceed said connection zone 163. Thus, tests are conducted to determine the value of the internal diameter dp between at least two values and adjust the jet distance "L" using a tapped end zone 162 of three-way T-connector 161 in which 190 threaded reduction nozzles of different diameters dp are successively connected. A pressure sensor measures the pressure losses created by the jet 203.

Each reduction tip 190 is threaded externally to allow the displacement of the threaded end 190 in the tee fitting 161 and thus change the jet distance "L" of the tip 190 to the first output port 132 of the plate heat exchanger 130.

Adjusting the jet distance "L" by displacement of the threaded end 190 on the threaded end zone 162 then allows the jet 203 to be adapted for the selected inner diameter dp.

In an exemplary embodiment, the reduction tip 190 may be in the form of a ring fixed by brazing, crimping, gluing or screwing on the inner wall 164. The ring forms a through hole 191, centered by relative to the inner wall 164 of the T-piece 161 and extending along the main longitudinal axis X'X of the purge supply pipe 160 coinciding with that of the wall 164. Alternatively, the reduction nozzle may be a nozzle or any type of equivalent annular tip parallel axis or non-parallel to the main axis X'X depending on the type of connection connected to the output port 132.

In the case of tubular pipes, this ring is annular and its outer diameter substantially corresponds to the inner diameter dr of the inner wall 164 of the tee fitting 161.

In the illustrated example, the sanitary cold water jet 203 is in the form of a straight jet at the outlet of the reduction nozzle 190.

The right jet concentrates the stream of sanitary cold water 203 in a substantially cylindrical shape and is maintained in this form for a sufficient length to cross the connection zone 163 of the fitting. in Tee 161. The jet 203 thus enters the first outlet port 132 of the exchanger 130 and fills it with water. The shear forces caused by the jet penetrating into the turbulent water body 204 contained in the port 132 prevent the sanitary cold water from returning to the sewage collection line 170 and dragging it through the cooling plates. the exchanger 135.

Such a reduction of sanitary cold water flow 202 thus makes it possible to overcome a hydraulically controlled sleeve valve in the sewage collection pipe 170 to block the passage of the sanitary cold water in this zone. pipe 170 when the purge valve is in the open position.

The above description clearly illustrates that by its different characteristics and their advantages, the present invention achieves the objectives set. In particular, it provides a device for recovering the thermal energy gray water simple embodiment, small and simplified while substantially improving the purge flow, for example by doubling or more with the type of device detailed above . No controlled sleeve valve is required to switch from a nominal operating mode to a purge mode and vice versa.

The present invention is not limited to the examples or embodiments described and made. Thus, the sanitary cold water supply pipe can be arranged, in the three-way connection with the outlet port of the adapted type of exchanger, between the sewage collection pipe and said outlet port, and therefore upstream of the sewer collection line in the direction of the greywater flow.

Moreover, the pipes and the reduction tip may be of non-circular section, for example oblong, oval, annular and / or polyhedral.

In addition, the axis of the reduction head of sanitary water flow may coincide with that of the supply line of this sanitary water or form with this axis an appropriate angle to better orient the jet to the outlet port of the exchanger, the angle being adjusted according to the connection angles of the connection used (Y, Tee or panties).

In addition, any type of reducing means tip or equivalent may be suitable, whether a tube, a sleeve, a ring, a nozzle or the like. Furthermore, the adjustment of the jet distance and the choice of the diameter value of the reduction tip - in the case of a circular tip - can be made by successive approximations.

Claims

1. Device (1) for recovering the thermal energy of an optimized cleaning fluid flow, comprising a plate heat exchanger (130) through which a first and a second separate fluid stream pass, said exchanger (130) being provided with first input port (131) and output port (132) of the first fluid and second input (133) and output (134) ports of the second fluid, and a network of hydraulic lines (10) connected to said exchanger ( 130) and having an inlet pipe (180) of the first fluid in hydraulic communication (141) with said first inlet port (131), an overflow pipe (150) in hydraulic communication on the one hand (141). ) with the inlet pipe (180) and on the other hand (171) with a sewage collection pipe (170), and a supply pipe (160) for the communicating purge cold water hydraulic system (161) with the first output port (132), characterized in that the hydraulic communication (161) of the inlet pipe (160) of the sanitary cold water comprises, at the inlet of a connection zone (163) with the sewage collection pipe (170), a means of reduction (190) of passage section of a flow of cold sanitary purge water (202) in the supply pipe (160), and a purge valve, arranged upstream of the reduction means (190) in the nominal flow direction of the sanitary cold water flow (202) and configured to temporarily allow passage of the cold water flow (202) to the first outlet port (132).

2. Device (1) according to claim 1, wherein the reduction means (190) comprises a reducing end of the flow section of the sanitary cold water flow (202) forming a through hole (191) of axis set with respect to a longitudinal axis (X'X) defined by the purge supply line (160).

3. Recovery device (1) according to claim 2, wherein the reduction tip (190) is a ring fixed in the supply line (160) of the cold water by a selected bonding between soldering, crimping, gluing and screwing.

4. Recovery device (1) according to any one of the preceding claims, wherein the purge valve is an electrically controlled valve.

The recovery device (1) according to any one of the preceding claims, wherein the hydraulic communications (141, 161, 171) are three-way couplings selected between a tee fitting, a panty joint 45 and 67 °, and a Y connection.

6. Recovery device (1) according to any one of the preceding claims, wherein on the one hand the inlet pipes of the first fluid (180) and overflow (150) and, secondly, the purge supply lines (160) and the first outlet port (132) are in the extension of one another.

7. Cleaning optimization method of the device according to any one of the preceding claims, characterized in that it consists in optimizing a purge flow by determining a compromise value of the inside diameter (d _p ) of the means. reduction device (190) between at least one higher value, which increases the flow rate of the purge stream (202) by reducing the pressure drops, and at least one lower value which generates a cold water jet velocity (203) higher and then increases the driving force of this jet (203), and by adjusting the jet distance (L) so that the sanitary cold water jet (203) is directed at the outlet of the reduction means ( 190) to the first output port (132).

8. Cleaning optimization method according to the preceding claim, wherein the choice of the inside diameter (dp) of the reduction tip (190) and the jet length (L) are guided by the measurement of pressure losses. created by the jet (203) and the purge flow, the purge flow being the flow of water through the exchanger (130) against the current of its first output port (132) at its first port of entry (131) and evacuating through the overflow line (150).