Tank for energy recovery

Abstract

A tank for waste water partially or fully buried in the ground or immersed in water includes a wall made of a high thermal conductivity material, which in turn has a pair of walls forming a cavity creating a circuit of a convective fluid for heat exchange with both the waste water contained inside the tank and with the ground and/or groundwater external to the tank.

Claims

1. A tank (1) for waste water (A) coming from civil, industrial, commercial, and agricultural units, adapted to be partially or fully buried, being in contact with a ground and/or groundwater or an underground body of water, comprising: a wall (11); a bottom (12); and a lid (13) for closure, wherein at least said wall (11) is made of a thermally conductive material, and wherein said wall (11) comprises a pair of walls (21, 22) forming a cavity (23), in which a circuit (Wb) is created for a convective exchange fluid (B) for heat exchange with both the waste water (A) contained inside (14) the tank (1) and with the ground and/ or water outside (E) the tank (1).

2. The tank (1), according to claim 1, wherein said circuit (Wb) for said exchange fluid (B) is connected to a heating/cooling pump (C).

3. The tank (1), according to claim 1, wherein said bottom (12) is made of a thermally conductive material and includes a double wall creating a cavity (24) communicating with said cavity (23) in the wall (11).

4. The tank (1), according to claim 1, further comprising at least one baffle and one or more dividers (15, 16, 17) mounted on an inside (14) of the tank (1) for separation of waste products and creating a circuit (Wa) for waste water (A) circulation between an inlet (S1) and an outlet (S1, S2), respectively connected to an incoming waste water pipe (S) and to an outlet pipe (F1) that leads to a public sewer network (F), wherein said baffle is T-shaped (15, 16) and is formed by a first baffle (15)M, which divides an interior (14) into two parts (141, 142) communicating with each other, and a second baffle (16) transverse to said first baffle (15), said T-shaped baffle (15, 16) being spaced from the bottom (12) of the tank (1) so as to create a passage (Al) for flow (Wa) of waste water (A) between said inlet (S1) and outlet (S2), which are placed near a top of the tank (1), and wherein, on the bottom (12) of said tank (1), there is at least one divider (17).

5. The tank (1), according to claim 4, wherein said at least one baffle (15, 16) comprises a double wall, which creates one or more cavities (25) communicating with said cavities (23, 24) of the wall (11) and the bottom (12) of the tank, such that said exchange fluid (B) also circulates in said cavity (25) of said baffles (15, 16), increasing an exchange surface with the waste water (A) inside (14) the tank (1).

6. The tank (1), according to claim 1, wherein at least one helical baffle (19) is mounted inside said cavity (23) of said wall (11) of the tank (1), the at least one helical baffle creating a substantially spiral forced path (Wb) inside said cavity (23) of said wall (11).

7. The tank (1), according to claim 6, further comprising a plurality of fins (18) which are configured to increase an exchange surface between the convective fluid (B) and the outside (E) of the tank (1), the plurality of fins being mounted at least outside said wall (11) of the tank (1).

8. The tank (1), according to claim 6, wherein said heat exchange fluid is a glycol based fluid (B) and that said wall (11), said bottom (12), and said baffles (15, 16) are made of stainless steel.

9. The tank (1), according to claim 2, wherein said circuit (Wb) of the exchange fluid (B) is connected to said heating/cooling pump (C) in two circuits, of which one is for hot season and one for cold season, and wherein said tank (V) comprises at least one pair of exchange fluid (B) delivery/return connections (B1, B2) for operation in the hot season and at least one pair of exchange fluid (B) delivery/return connections (B3, B4) for operation in the cold season.

10. The tank (1), according to claim 1, wherein the tank is cylindrical or prismatic, with a diameter between 80 and 100 cm and a height between 160 and 200 cm.

Description

[0044] FIGS. 1a, 1b and 1c respectively show a top view and two vertical sections of a new tank (1) illustrating the application as a fat and grease separator tank.

[0045] FIGS. 1b and 1c respectively show the circuit (Wa) of waste water (A) coming from a residential unit in general and the circuit (Wb) of the exchange fluid (B).

[0046] FIGS. 2a, 2b and 2c respectively show a top view and two vertical sections of the new tank (1) in a possible preferred embodiment.

[0047] FIG. 3 shows the connection of the new tank (1) to the waste water pipe (S) of the water from a residential unit to the supply pipe (F1) and to the sewer system (F).

[0048] FIG. 4 shows the connection of the new tank (1) to a heating/cooling pump (C).

[0049] This is a tank (1) for the separation of fat and grease in waste water (A) coming from a residential unit or building in general and is suited to be partially or fully buried, thus being in contact with the ground and/or with groundwater or an underground body of water in general.

[0050] The new tank (1) for the separation of fat and grease is made of a high thermal conductivity material, preferably stainless steel, and comprises a wall (11) preferably cylindrical or prismatic and preferably installed in a vertical position, a bottom (12), preferably convex and a lid (13) to close it.

[0051] At least the wall (11) and preferably also the bottom (12) are in turn made up of a double wall in highly conductive material or steel, an outer wall (21) and an inner wall (22), that create a hollow cavity (23, 24). In the preferred embodiment, this hollow cavity (23) created in the wall (11) communicates with the cavity (24) created in the bottom (12).

[0052] The interior (14) of the tank (1) in turn communicates via an inlet and outlet (S1, S2) respectively with a waste water pipe (S) for the waste water coming from a housing unit in general and with an outlet pipe (F1) that leads to the sewer system (F).

[0053] Inside (14) the tank (1) there are one or more baffles (15, 16) and in particular at least one baffle is a T-shape, formed by a first baffle (15) which divides the interior (14) into two parts (141, 142) communicating with each other and a further baffle (16) transverse to the first baffle (15).

[0054] Said T-shaped baffle (15, 16) is spaced from the bottom (12) of the tank (1) so as to create a passage (A1) for the flow (Wa) of the waste water (A) between the inlet (S1) and the outlet (S2), which are in turn located near the top of the tank (1).

[0055] On the bottom (12) of the tank (1) there is at least one divider (17) for the separation of fats and grease, which rises from the bottom (12) and has a height higher than the passage (A1) for the waste water (A), such as to form a barrier for fats and impurities contained in the waste water (A).

[0056] The flow (Wa) of the waste water (A) inside the tank (1), between the inlet (S1) and the outlet (S2), is shown schematically in FIGS. 1b and 2b.

[0057] A preferably glycol based heat exchange fluid (B) circulates inside the cavity (23, 24) in the wall (11) and in the bottom (12) of the tank (1).

[0058] In particular, within the cavity (23, 24) a circuit (Wb) is created for the exchange fluid (B), connected to a heat pump (C).

[0059] Said exchange fluid (B) is inserted into and removed from the tank (1) via multiple delivery and return connections (B1, B2, B3, B4).

[0060] In the preferred embodiment, there are two circuits, one for the hot season and one for the cold season, and therefore at least one pair of delivery/return connections (B1, B2) for operation in the hot season and at least one pair of delivery/return connections (B3, B4) for operation in the cold season.

[0061] Therefore, said exchange fluid (B) circulates within said cavities (23, 24) in the wall (11) and in the bottom (12) of the tank (1), and is therefore able to exchange heat with both the waste water (A) contained inside (14) the tank (1) and the outside (E) of the tank (1), that is, with the ground and/or groundwater.

[0062] Said tank (1) is appropriately sized as a function of the number of users to be served, and also in order to optimize the efficiency of the heat exchange with both the waste water (A) and with the external ground/groundwater (E), and has, for example, a diameter between 80 and 100 cm and a height preferably between 160 and 200 cm.

[0063] To improve the circulation of the exchange fluid inside said cavity (23) in the wall (11) of the tank (1) between the inner wall (21) and the outer wall (22) there is at least one helical baffle (19) installed suited to create a forced spiral path (Wb) inside said cavity (23), so as to convey the heat exchange fluid (B) across most of the surface.

[0064] For this purpose, the new tank (1) may include one or more temperature probes placed in said cavities (23, 24, 25) or in other parts of the tank (1).

[0065] To increase the heat exchange surface with the interior (14) of the tank (1), said baffles (15, 16) are also made of material with high thermal conductivity, preferably stainless steel, formed by a double wall creating one or more cavities (25) communicating with said cavities (23, 24) of the wall (11) and the bottom (12) of the tank. In this way the glycol based fluid (B) also circulates in said cavity (25) in the baffles (15, 16).

[0066] To increase the heat exchange surface with the outside (E) of the tank (1), a plurality of fins (18) are mounted, preferably welded, and arranged, for example, radially and evenly distributed on the outside of said wall (11) of the tank (1). The exchange surface between the glycol based fluid (B) and the outside (E) is thus the sum of the surfaces of all the fins (18), the outer surface of the wall (11), and the outer surface of the bottom (12).

[0067] Said circuit (Wb) of the glycol based fluid (B) communicates with at least one heat pump (C), by means of suitable electromechanical devices, valves, sensors, and the like which are needed for the proper management of the system.

[0068] These specifications are sufficient for the expert person to make and use the invention, as a result, in the practical application there may be variations without prejudice to the substance of the innovative concept.

[0069] Therefore, with reference to the preceding description and the attached diagrams the following claims are made.