# US 11,306,978 B2 · Heat recovery apparatus and method

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- Number: US 11,306,978 B2
- Document ID: US11306978B2
- Status: Granted
- Kind: B2
- Application number: 16/238,253
- Filed: 2019-01-02
- Published: 2019-05-09
- Granted: 2022-04-19
- Earliest claimed: 2014-09-05
- Assignees: 2078095 Ontario Limited
- Applicants: 2078095 Ontario Limited
- Inventors: Vicente Gil; John Gil; Camilo Gil; Adelino Ribeiro; David Ribeiro
- Web page: https://patentgrep.com/patent/US11306978B2

## CPC

- F28D 21/0012: {the heat being recuperated from waste water or from condensates}
- F28D 7/0075: {with particular circuits for the same heat exchange medium, e.g. with the same heat exchange medium flowing through sections having different heat exchange capacities or for heating or cooling the same heat exchange medium at different temperatures}
- F28D 7/024: {the conduits of only one medium being helically coiled tubes, the coils having a cylindrical configuration}
- F28D 7/103: {consisting of more than two coaxial conduits or modules of more than two coaxial conduits}
- F28D 7/12: the surrounding tube being closed at one end, e.g. return type (F28D7/14 takes precedence)
- F28D 7/1607: {with particular pattern of flow of the heat exchange media, e.g. change of flow direction (F28D7/1623, F28D7/1638, F28D7/1661, F28D7/1676, F28D7/1692 take precedence)}
- F28D 9/04: the conduits being formed by spirally-wound plates or laminae
- F28F 1/36: the means being helically wound fins or wire spirals
- Y02A 20/30: Relating to industrial water supply, e.g. used for cooling
- Y02B 30/56: Heat recovery units
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A grey water heat recovery apparatus has first and second passes in counter-flow orientation. The hot side is grey water. The cold side is fresh water. It extracts heat from the grey water. The fresh water is carried in tubing bundles in series immersed in grey water sumps in cylindrical plastic, mild steel, or stainless steel pipe. Both ends of the fresh water bundle assembly extend from the same upper end pipe closure, without a pressurized line wall penetration in the walls of the pipe. There is a non-electrically conductive barrier between the fresh water and grey water flow paths. The apparatus has a leak detection circuit and co-operable bypass valves. The tube bundle is wider at the top than at the bottom. The lower manifold has grey water passages between the centering ears. The entire assembly is enclosed in a unitary external housing with easily accessible connection fittings.

## Claims

### Claim 1

A grey water heat recovery apparatus comprising:
at least a first heat exchanger pass having an external shell and a tube bundle;
said external shell being formed of a cylindrical pipe;
said cylindrical pipe having a first end and a second end;
in operation, said first end being located higher than said second end;
said second end being blocked to form a sump within said cylindrical pipe;
said cylindrical pipe having a first port and a second port;
said first port being nearer to said first end than to said second end;
said first port being nearer said first end than is said second port; said first port defining a resting water level when gray water is contained in said sump;
one of said first and second ports defining an inlet for grey water to said cylindrical pipe, the other of said first and second ports defining an outlet for grey water from said cylindrical pipe, said cylindrical pipe defining a flow path for grey water between said inlet and said outlet thereof;
said first end of said cylindrical pipe providing an entry;
said tube bundle being sized to fit within said entry at said first end of said pipe;
said tube bundle being axially slidable within said external shell;
said tube bundle having a first end and a second end;
said tube bundle having a first manifold at said first end thereof, and a second manifold at said second end thereof;
said tube bundle including an array of pipes, said pipes of said tube bundle being in fluid communication with said first manifold and said second manifold, said pipes of said array each having a respective first cross-sectional area;
said tube bundle including a return extending upwardly beyond said first manifold and extending downwardly to said second manifold;
said return having a second cross-sectional area;
said first cross-sectional area being less than said second cross-sectional area, said first manifold and said second manifold fitting within said cylindrical pipe;
as installed, said second end of said tube bundle being closer to said second end of said cylindrical pipe than is said first end of said tube bundle;
said tube bundle having an inlet and an outlet, said tube bundle defining a fresh water flow path between said inlet and outlet thereof;
both said inlet and said outlet of said tube bundle being located at said first end of said tube bundle; and
as installed in said cylindrical pipe, said inlet and said outlet of said tube bundle being accessible at said first end of said cylindrical pipe at a level higher than said resting water level of said cylindrical pipe.

### Claim 2 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said cylindrical pipe has at least one of (a) an inside diameter less than 8 inches; and (b) a length to diameter ratio of greater than 8:1.

### Claim 3 (depends on 1)

A grey water heat recovery apparatus comprising at least a first and a second heat recovery apparatus of claim 1 mounted side-by-side and joined together in fluid communication in series.

### Claim 4 (depends on 3)

The grey water heat recovery apparatus of claim 3 wherein at least said first and second heat recovery apparatus are mounted together within a single housing.

### Claim 5 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said tube bundle includes a set of helical coils extending around said return.

### Claim 6 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said second end of said cylindrical pipe has a valve mounted thereat, and said valve is operable to permit flushing of said sump.

### Claim 7 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said apparatus includes a leak detector.

### Claim 8 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said return is at least partially insulated.

### Claim 9 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said array of pipes is spaced about said return pipe; and said array of pipes has a tighter footprint at said second manifold than at said first manifold.

### Claim 10 (depends on 1)

The grey water heat recovery apparatus of claim 1 wherein said second manifold has a smaller outside wall diameter than does said first manifold.

### Claim 11

A grey water heat recovery apparatus comprising:
a pipe and a tube bundle;
said pipe having a first end and a second end, said first end being an upper end and said second end being a lower end;
said pipe having a cylindrical pipe wall and a first grey water port and a second grey water port formed in said cylindrical pipe wall;
said first grey water port being closer to said first end of said pipe than to said second end of said pipe and defining a resting water level when grey water is contained within said pipe;
said tube bundle having a first manifold, a second manifold, a return pipe, and a pipe array;
said tube bundle including said first manifold and said second manifold insert axially to seat within said cylindrical pipe wall on installation;
said pipe array of said tube bundle having at least a first pipe having a first cross sectional area;
said return pipe having a second cross-sectional area;
said second cross-sectional area being greater than said first cross-sectional area;
said return pipe being in fluid communication with said second manifold and passing axially upwardly beyond said first manifold to terminate at a first pipe connection;
said pipe array extending between, and being in fluid communication with both said first manifold and said second manifold; said first manifold having a second pipe connection extending upwardly therefrom, said second pipe connection being in fluid communication with said first manifold; and, at least one of
(a) said pipe array has a smaller connection footprint with said second manifold than with said first manifold; and
(b) said second manifold has a peripherally extending wall, said first manifold has a peripheral wall, and said peripheral wall of said second manifold has a shorter periphery than has said peripheral wall of said first manifold.

### Claim 12 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein said pipe array has a smaller connection footprint with said second manifold than with said first manifold.

### Claim 13 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein said second manifold has a peripherally extending wall, said first manifold has a peripheral wall, and said peripheral wall of said second manifold has a shorter periphery than has said peripheral wall of said first manifold.

### Claim 14 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein said first pipe has a straight portion extending axially from said first manifold, and a bent portion extending from said straight portion toward said second manifold.

### Claim 15 (depends on 14)

The grey water heat recovery apparatus of claim 14 wherein said straight portion is more than twice the length of said bent portion.

### Claim 16 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein:
said peripheral wall of said first manifold has a first diameter;
said peripheral wall of said second manifold has a second diameter; and
said second diameter is smaller than said first diameter.

### Claim 17 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein said second manifold has a set of centering ears extending radially outwardly thereof.

### Claim 18 (depends on 17)

The grey water heat recovery apparatus of claim 17 wherein a grey water flow path is defined outwardly of said second manifold, inwardly of said cylindrical pipe, and sectorally between an adjacent pair of said centering ears.

### Claim 19 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein said pipe array has a total cross-sectional flow area that is at least as great as the cross-sectional flow area of said return pipe.

### Claim 20 (depends on 11)

The grey water heat recovery apparatus of claim 11 wherein:
both of (a) said pipe array has a smaller connection footprint with said second manifold than with said first manifold; and (b) said second manifold has a peripherally extending wall, said first manifold has a peripheral wall, and said peripheral wall of said second manifold has a shorter periphery than has said peripheral wall of said first manifold;
said first pipe has a straight portion extending axially from said first manifold, and a bent portion extending from said straight portion toward said second manifold;
said straight portion is more than twice the length of said bent portion;
said peripheral wall of said first manifold has a first diameter;
said peripheral wall of said second manifold has a second diameter;
said second diameter is smaller than said first diameter;
said second manifold has a set of centering ears extending radially outwardly thereof;
a grey water flow passage is defined outwardly of said second manifold, inwardly of said cylindrical pipe, and sectorally between an adjacent pair of said centering ears; and
said pipe array has a total cross-sectional flow area that is at least as great as the cross-sectional flow area of said return pipe.