MX2011002429A - Heating system with optimized recovery of waste water heat. - Google Patents

Abstract

The invention relates to a heating system with recovery of waste water heat that includes a heat pump, a waste water holding vat (10) that includes a casing (34), defining an internal space (36) for holding the waste water, and a heat exchanger (26, 28) for recovering calories in the holding vat (10) and using them in the heat pump. The holding vat (10) includes at least one baffle (44) that extends into the holding space (36), divides the holding vat (10) into a plurality of compartments (46), and defines, with the casing (34), a waste water flow path that bypasses the baffle(s) (44) and passes into the compartments (46). The heat exchanger (26, 28) is arranged so as to recover calories in at least two compartments (46).

Description

HEATING SYSTEM WITH OPTIMIZED RECOVERY OF WASTEWATER HEAT The present invention relates to a heating system with wastewater heat recovery, of the type comprising a heat pump, a. wastewater retention tank comprising an enclosure delimiting an internal volume of wastewater retention, and a heat exchanger to recover calories in the retention tank and use them in the heat pump.

FR-A-2 885 406 describes a heating system with wastewater heat recovery comprising a wastewater retention tank ensuring a vertical thermal stratification of wastewater and a heat pump whose evaporator is integrated into the retention tank, and receives wastewater that comes from the hottest part of sewage from the holding tank.

However, the volume of the holding tank is important.

An object of the invention is to provide a heating system with heat recovery of waste water whose saturation is weak, offering a high energy efficiency.

For this purpose, the object of the invention is a heating system of the aforementioned type, characterized in that the retention tank comprises at least one deflection plate extending in the retention volume and dividing the retention tank in a plurality of compartments and defining with the wrapping a wastewater flow path surrounding the deflection plates and passing in the compartments, the heat exchanger is positioned so as to recover the calories in at least two compartments.

Following the particular embodiments, the heating system according to the invention comprises one or more of the following characteristics, taken in isolation or following all the technically possible combinations: the wastewater flow path passes successively in each compartment; the at least one deflection plate comprises a free edge delimiting with the envelope a wastewater flow passage; - the holding tank comprises • less a first deflection plate and at least one second deflection plate placed the second inverted with respect to the first; the at least one deflection plate is horizontal or vertical; the exchanger is formed in the at least one deflection plate comprising an internal conduit for circulating a heat transfer fluid; - the internal duct forms a circuit comprising several parallel and opposite direction of circulation parts; the system comprises at least two deflection plates provided with internal conduits joined in series to form the exchanger; the heat pump comprises an evaporator and a condenser connected by a primary circuit for the circulation of a cooling fluid, and a secondary circuit for the circulation of a heat-carrying fluid, joining the exchanger to the evaporator.

The invention also relates to a heating installation comprising a waste water source, a heating system with waste heat recovery and a heating application such as a central heating circuit or domestic hot water, the heating application feeding with calories by the heating system, characterized in that the heating system is as defined above, the wastewater source joining to an inlet of the holding tank.

The invention will be better understood by reading the following description, given only by way of example, and made referring to the accompanying drawings, in which: Figure 1 is a diagram representing a heating installation comprising a heating system with wastewater heat recovery, according to the invention; Figure 2 is a side view in vertical section of a waste water holding tank and a heat exchanger of the heating system of Figure 1; Figure 3 is a partial side view of the holding tub of Figure 2, in which an insulating layer of the tub has not been shown; - Figure 4 is a schematic view in vertical section following the line IV-IV of Figure 2; Figure 5 is a view analogous to Figure 1 of a holding tank of a heating system according to a second embodiment of the invention; Figure 6 is a schematic view illustrating a heat exchanger formed by several internal deflection plates to the holding tank of Figure 5; Figure 7 is a sectional view of one of the deflection plates of Figure 6; Figure 8 is a view analogous to Figures 2 and 5 of a holding tank of a heating system according to a third embodiment of the invention, the holding tank being provided with a decanting vessel; Y - Figure 9 is a schematic view of an exchanger formed by a plate of internal horizontal deflection to the holding tank of Figure 8.

Figure 1 illustrates an individual heating installation 2 comprising a heating system 4 with heat recovery of waste water and a heating application 6 supplied with heat by the heating system 4.

The heating application 6 is for example a radiator, domestic hot water circuit, a heating floor, or a hot air network.

The heating installation 2 further comprises one or more sources 8 of warm waste water, receiving waste water coming for example from a shower, a washing machine, a washing machine, a tub.

The heating system 4 comprises a wastewater holding tank 10, fed by the source 8, and a heat pump 12 using the heat provided by the wastewater of the tank 10.

The heating installation 2 also comprises a central control unit 7 guiding the heat pump 12 and the final application 6.

The heat pump 12 conventionally comprises an evaporator 14, a compressor 16, a condenser 18 and a decompressor 20 connected in series by a primary circuit 22 of cooling fluid.

The holding tank 10 comprises an internal exchanger 26 and an external exchanger 28 connected in parallel to the evaporator 14 by a secondary circulation circuit 30 of a heat transfer fluid.

The secondary circuit 30 comprises a pump 30A ensuring the circulation of heat transfer fluid, a diverting conduit 30B of exchangers 26 and 28 and a three-way gate 30C selectively securing the closing of the diversion conduit 30B or of the exchangers 26 and 28.

The secondary circuit 30 also comprises a control and adjustment unit 30D guiding the three-way gate 30C and the pump 30A, and a temperature sensor 30E of the heat transfer fluid circulating in the secondary circuit 30. The control unit and • regulation 30D receives - a temperature measurement signal provided by temperature sensor 30E, and joins central unit 7.

The secondary circuit 30 is further joined to an expansion vessel 30F.

The waste water holding tank 10 will now be described in more detail, with respect to Figures 2 to 4.

The tank 10 is emptied by overflow: the water enters the tank 10 and leaves it when it is discharged through an outlet when the level of the water in the tank reaches that of the outlet.

The tub 10 comprises a casing 34 delimiting an internal volume 36 for retention of wastewater, an inlet 38 for wastewater in the holding volume 36, and a wastewater outlet 40 from the holding volume 36.

The casing 34 comprises a cylindrical wall 41 with a horizontal axis, and two vertical walls 42 closing the cylindrical wall 41 at their respective ends. The holding volume 36 is delimited by the inner surface of the walls 41 and 42.

The holding volume 36 has a length comprised between lm and 4m, preferably between l, 4m and 2.5m, and a diameter comprised between 0.4m and 2m, preferably between 0.4m and lm. The dimensions are chosen according to the final application 6.

The wastewater inlet 38 and the wastewater outlet 40 are respectively formed in the opposite vertical walls 42, each through a hole through the wall 42 and opening into the holding volume 36.

The inlet 38 and the outlet 40 are located in an upper part of the holding tank 10, at the same height.

The height of the outlet 40 in the holding volume 36 defines the maximum level of wastewater in the holding volume 36 from which the wastewater from the holding volume 36 overflows the outlet 40.

The tank 10 comprises a plurality of deflection plates 44 extending into the retention volume 36. The deflection plates 44 are positioned so as to modify the direct path of the water between the inlet 38 and the outlet 40, imposing a winding path surrounding the desalination plates 44.

The tub 10 comprises several deflection plates 44 distributed regularly along the axis of the tub 10.

The deflection plates 44 divide the retention volume of the tub 10 into a plurality of compartments 46.

Each deflecting plate 44 in effect forms on the one hand and two other compartments 46. In the illustrated example, the tub has three deflection plates 44 defining four compartments 46.

Each deflection plate 44 has a general plate shape, more precisely a truncated disc. They delimit each one, a continuous surface.

Each deflection plate 44 comprises - ii - an edge 48 for joining the envelope 34, complementary to the envelope 34, and a free edge 50 defining a flow passage 52 with the envelope 34. The edge 50 is horizontal.

The flow passages 52 are located at a lower level than the waste water outlet 40.

The deflection plates 44 are parallel to each other and the second inverted with respect to the first is placed alternately. The deflection plates 44 are vertical. The bypass steps 52 are formed alternately in the bottom and upper part of the holding volume 36.

In the illustrated example, one of the deflecting plates 44 extends upwardly from the bottom of the wrapping 34 while the other two deflecting plates 44 are placed on one side and the other and extend downwardly. from the top of the envelope 34.

The deflection plates 44 define with the envelope 34 a flow path of wastewater from the inlet 38 to and to the outlet 40. The flow path passes successively in each compartment 46. It comprises several changes of direction of the waste water circulation , to surround the deflection plates 44.

These changes of direction, in the illustrated example, are comprised between 90 ° and 1800.

The volume of the tank 10 is greater than 20 times the passage section per unit length of inlet and outlet ducts, preferably greater than or equal to 40 times.

In the illustrated example, this report is 45.

The wastewater flow time along the flow path is therefore equivalent to the wastewater flow time in a passage section duct identical to inlet 38 and outlet 40, and whose length will be 45 times higher .

The heat exchangers 26 and 28 are placed to recover calories in the holding tank 10. The exchangers 26 and 28 are connected in parallel to the secondary circuit 3.0 and each have a manual gate 58 for regulating the flow rate.

The internal exchanger 26 comprises a plurality of conduits 60 extending into the holding volume 36.

Each conduit 60 passes successively through each of the compartments 46. The internal exchanger 26 is thus adapted to recover the calories in each of the compartments defined by the deflection plates 44.

The conduits 60 are joined in parallel. They are also placed parallel to each other.

Each conduit 60 comprises two vertical parts 62 and a horizontal part 64 joining the two vertical parts 62 at their lower extremities. Each conduit 60 thus forms a U.

The horizontal part 64 extends into the bottom of the tank 10, over substantially the entire length of the tank 10. The horizontal part 64 extends in the flow passages 52 defined by the upper deflection plates 44 and passes through the deflection plate. 44 lower.

The external exchanger 28 comprises a helical conduit 66 extending in helix around the envelope 34, over substantially the entire length of the envelope 34.

The external exchanger 28 is placed in an insulating layer 68 surrounding the outer envelope 34. The insulating layer 68 prevents heat losses from the tank 10.

The holding tank 10 further comprises two access traps 72 placed respectively on the vertical walls 42 of the outer envelope 34.

The diameter of the access traps 72 is important, on the order of half the diameter of the tank 10, for easy cleaning 1.

Finally, the holding tank 10 is provided with a temperature sensor 73 and a water level sensor 74 connected to the central control unit.

The operation of the invention will now be described.

The start-up of the heating system 2 is carried out by means of the central control unit 7.

The central control unit 7 sends a routing signal in the final application 6, to the heat pump 12 and to the control and regulation unit 30D of the secondary circuit 30.

The control and regulating unit 30D guides the pump 30A and the three-way gate 30C according to the control signals provided by the central unit 7 and / or the temperature value provided by the temperature sensor 30E.

In a variant, the control and regulating unit 30D also guides the gates 58 for regulating the flow rate of the exchangers 26 and 28.

The circulation of heat carrier fluid in exchangers 26 and 28 heats the heat carrier fluid. The heat transfer fluid passes through the evaporator 14, yielding heat to the cooling fluid. This is cooled in the condenser 18 providing the heat to the final application 6.

For these reasons of safety and energy saving, the central control unit 7 stops the installation if the temperature value provided by the temperature sensor 73 of the tank 10 is very low and / or if the water level sensor 74 detects a very low level of water in the tank 10.

With the invention, the deflection plates 44 impose a flow path successively on the waste water in several compartments 46 from which the exchangers 26 and 28 recover the heat. The wastewater arriving at the entrance is forced to pass in each compartment 46, this ensures an important recovery of the heat of these inlet waters by the exchangers 26 and 28. The energy efficiency of the installation 2 rises. The volume required for the holding tank 10 is weak.

The importance of the wastewater flow time around the deflection plates 44 ensures an optimal recovery of their heat by the exchangers 26 and 28.

The deflection plates 44 prevent a vertical thermal stratification of waste water in which the hottest water will be found in the upper part of the tank 10, which will lead to a very fast flow of hotter waters.

In addition, the deflection plates 44 do not induce a risk of blockage of the tub 10.

The placement of exchangers 26 and 28 ensures an important surface of the heat exchanger with the waste water present in the holding tank 10.

The pouring overflow of the tank 10 limits the risk of blockage of the tank 10. In fact, the presence of a gate 10 at the level of the outlet 40 is useless. The Cuba is weak.

In addition, the risk of obstruction of the outlet 40 by an aggregate of particles is very weak.

The use of a secondary circuit 30 for circulating a heat transfer fluid joining the exchangers 26 and 28 to the evaporator 14 makes it possible to adapt the holding tank 10 to the pre-existing heat pumps 12.

In addition, the heat pump 12 is removable without intervention in the holding tank 10, which facilitates the assembly and maintenance operations of the installation 2.

In alternative, the heating installation 2 is that of a building.

Figures 5 to 7 illustrate a heating system 4 according to a second embodiment of the invention whose only differences with respect to the first embodiment will be described below. In Figures 5 to 7, the analogous elements in the first embodiment are designated by identical reference numerals.

The heating system 4 according to the second embodiment differs essentially by the holding tank 10. The internal exchanger 26 and the external exchanger 28 have been replaced by a single exchanger 76 formed by the deflection plates 44 of the tank 10.

Indeed, as illustrated in Figures 6 and 7, each deflection plate 44 delimiting an internal conduit 78 for circulating a fluid carrier.

The internal duct 78 comprises deflection plates that make it possible to impose a long path and a long circulation time to the thermoportant fluid in the internal duct 78, favoring heat exchanges.

The inlet of each conduit 78 of each deflection plate 44 is joined to the outlet of the adjacent deflection plate 44. The deflection plates 44 are thus joined in series to form the exchanger 76.

The deflection plates 44 relate to holes 79 placed in the cylindrical wall 41 of the casing 34, and are joined together on the outside of the casing 34.

In addition, the number of deflection plates 44 has increased. The number of deflection plates 44 is henceforth such that the passage section of the wastewater flow path between the deflection plates 44 is substantially constant in the vessel 10.

The exchange surface of exchanger 76 is very important.

Figures 8 and 9 illustrate a heating system 4 according to a third embodiment of the invention, in which only the differences with respect to the second embodiment of the invention will be described below. Identical reference elements designate analogous elements.

The heating system 4 according to the third embodiment differs essentially from the heating system 4 according to the second embodiment in which the tank 10 comprises horizontal deflection plates which impose a sinuous path from the bottom of the tank 10 towards the outlet 40 in the top of the tank 10 and in which the tank 10 comprises a container 82 for settling waste water.

The horizontal deflection plates 44 have a complementary outline of the wrapping 34. Thus they have a rectangular general contour, which facilitates their manufacture.

Certain horizontal deflection plates 44 have an internal conduit 78 and form the exchanger 76.

In the illustrated example, only one horizontal deflection plate 44 on two forms the exchanger 76, the other horizontal deflection plates 44 being devoid of the transport fluid circulation conduit and placed alternately with the deflection plates 44 forming the exchanger 76. This will reduce the saturation of the tank 10 as well as the cost of the exchanger 76. However, in a variant, each horizontal deviation plate 44 forms the exchanger 76.

In addition, as illustrated by Figure 9, the deflection plates 44 comprise a transverse hole 80 forming the flow passage 52 of wastewater.

The settling tank 82 is placed in the bottom of the tank 10. It is placed next to the sewage inlet 38.

Decanting vessel 82 is converging downward, more precisely tapered downwardly. The container 82 has, at its lower end, a drain gate 8.

The tub 14 comprises a vertical inlet deflection plate 86 which imposes the wastewater entering the tank 10 to descend towards the bottom in the direction of the container 82, before going back up to the outlet 40 following the path defined by the plates horizontal deviation 44.

The operation of the settling tank 82 is simple. For the cleaning of the tank 10, it is sufficient to open the emptying gate 84. The particles accumulated in the container 82 are then evacuated.

Decanting vessel 82 facilitates maintenance operations.

The placements of the container 82 and deflection plates 86 and 44 improve the guidance of the particles present in the wastewater to the container 82. These placements also limit the rise of particles.

Claims (11)

1. Heating system with wastewater heat recovery, of the type comprising: a heat pump; a waste water holding tank comprising an envelope delimiting an internal volume of wastewater retention; and a heat exchanger to recover calories in the holding tank and use them in the heat pump; characterized in that the retention basin comprises at least one deflection plate extending into the retention volume and dividing the retention basin into a plurality of compartments and defining with the wrapping a wastewater flow path surrounding the deflection plates and passing through. in the compartments, the heat exchanger is placed so as to recover the calories in at least two compartments.

2. The heating system according to claim 1, wherein the passage section of the wastewater flow path between the deflection plates is sensitively constant.

3. Heating system according to any of the preceding claims, in which the wastewater flow path passes successively in each compartment.

. Heating system according to claim 1 or 2, wherein the at least one deflection plate comprises a free edge delimiting a waste water flow passage with the envelope.

5. Heating system according to any of the preceding claims, wherein the holding tank comprises at least one first deflection plate and at least one second deflecting plate placed the second inverted with respect to the first.

6. Heating system according to any of the preceding claims, wherein the at least one deflection plate is horizontal or vertical.

7. Heating system according to any of the preceding claims, in which the exchanger is formed in the at least one deflection plate comprising an internal circulation conduit of a transporting fluid.

8. Heating system according to claim 7, in which the internal duct forms a circuit comprising several parallel and opposite direction of circulation sections.

9. Heating system according to claim 7 or 8, comprising at least two deflection plates provided with internal conduits joined in series to form the exchanger.

10. Heating system according to any of the preceding claims, in which the heat pump comprises an evaporator and a condenser connected by a primary circuit for the circulation of a cooling fluid, and a secondary circuit for the circulation of a thermoplastic fluid, joining the exchanger to the evaporator.

11. Heating installation comprising a sewage source, a heating system with wastewater heat recovery and a heating application such as a central heating circuit or domestic hot water, the heating application being fed with calories by the heating system heating, characterized in that the heating system is according to any of the preceding claims, the source of wastewater joining an inlet of the holding tank.