A Horizontal Gyrating Heat Exchanger

FIELD OF INVENTION

The invention relates to waste heat recycling using a horizontal exchanger method for the recovery of heat from waste water discharged from households and commercial businesses, such as from showers, basins, baths, dishwashing machines, kitchen sinks, laundry washing machines, etc.

BACKGROUND ART

Despite, the rising cost of energy, the need to reduce greenhouse gases and greater emphasis on energy conservation and clean energy sources, heated waste water is typically disposed down a drain, with a resultant waste of its energy.

There are a number of known heat-recovery systems that recover heat from waste water from households and industry.

For instance, one heat recovery system is manufactured and sold by Water Cycles Energy Recovery, based in the Canadian province of Saskatchewan. The Water cycles heat-recovery system recovers energy from water flushing down drains in residential and commercial applications. It uses no energy itself, and there are no moving parts. The Water Cycle has a copper coil system and forms part of the wastewater pipe to extracts heat from wastewater. This heat is then conveyed to incoming fresh water before it reaches the water tank, thus pre-heating the supply. Commercial applications are typically multiple shower installations in fitness centres and swimming pools, and dishwashers in commercial kitchens.

This is significant, as New Zealand ih 2006, the energy consumed for domestic hot water use averaged 29% of domestic total and 35% for electricity only users.

Other internationally commercially available.products for domestic heat recovery systems include:

• Verticall (basement) exchangers, the 90 x 90 x 1500mm variant, stated as recovering 50% to 60% of energy,

· A shower cubicle integrated (cone shaped) solution is stated to recover 47% of energy,

·. Ah under-bath model measuring 600 x 300 x 100mm, is stated as recovering 40% of energy.

DISCLOSURE OF THE INVENTION

TECHNICAL PROBLEM

The perceived weaknesses of current systems are;

1 . Houses without serviced basements lacking run-off line fall for vertical exchangers 2 Situations lacking space for low cost installation

3 Too few stand alone solutions, slowing uptake

4. Inadequate response time for short burst use, that is slowing pay back, not regarding losses from old pipe runs, which compete for significance with the herein proposed loss from actual use alone

5 Existing art won't work well with low water pressure systems

6 No easy access for performance upkeep, slowing pay back

7 No unit standard for reporting thermal power of recovery, confusing consumers.

TECHNICAL SOLUTION

A Horizontal Gyrating Heat Exchang

The invention aims to provide a system for the recovering of heat from sanitation run-off systems, especially for short burst use such as hand washing and showering to overcome weaknesses of the known art or at least provide the public with a useful choice.

In an experiment, a near 90 % retrieval of heat was achieved using only 36%, by length, of medium transporting conduit, relative to background art. (Not counting mass nor 2" wall arrangements).

Repeated test outcomes showed that current art used excessive over length of copper conduit that was in part self- defeating its purpose in three ways, being:

Over-length arguably lead to dominant resistance to transfer;

· Over-length lead to loss of recaptured heat due to increased time for delivery, particularly in short burst use;

The above losses and the extra cost of copper slowing payback, weakening the propensity for potential users to engage.

While pointing to Fig.1 -3, this spec offers a compact, stand alone solution for hot water rinsing. The ideal pictured scenario uses a domestic flow demand for processing not exceeding 13 litres per minute and an in-floor or sub-floor cavity installation where the drainpipe allows for 105mm additional fall above the level of a gulley trap, with a system that intersects the horizontal drainpipe resembling an inspection joint.

Horizontal gyration of the spillage on a heat transfer processing platform (C), retrieves the energy in a shallow and compact way. Using a small pipe conduit, characterizing good drag, to return the pre-warmed medium in under ½ a second per metre. The pipe, (10,11) now short, cuts flow resistance to suit installation with low pressure systems. In-service access is provided (T).

This spec uses a moulded routing system (T), a shallow rigid close wound spiral conduit (C), ^' snug fit in a moulded circular outer shell. The shell (HE) wall has a curved shape and is equipped with an internal spout (6) to impart extra flow momentum and uses variable guide means (7) and transposable connections (9-1 1) to manipulate the flows to suit the domestic application range. By generating decreasing or increasmg cycles of the spillage, selectable to equal or outnumber revolutions of the medium flow, heat transference can be refined for desired flow demand. (Attribute Category.1 -12)

The developed product referred to in the descriptive spec paragraph No 1 (§ 1) comprises

a single module assembly consisting of:

· a shell top, critically routing the heat carrying spillage (1 ) to a spout (Cat.2-6) Fig.3-(6)

a shell base B, housing the conduit C for the heat transfer medium Fig.3

a shell and conduit with dependent variable attributes for control options (Cat.1-12) Fig.3

a shell base for collecting (13) and expelling (15) the heat starved spillage Fig.2 & 3-(l , 15)

provision for service access options Fig.3 (12), levelling, suspension and bulkhead connectors (as in Fig.2- 9, 14)

It will be purpose factory assembled for end users desired flow rate range, water supply line characteristics and code compliance requirements.

§ Number is as claim number (Item Numbers) and Capital letters refer to corresponding markings in the drawings Fig. # indicators are referring to drawing # in appendix Category Number, (Cat. #) refers to Attributes see Page 7

ADVANTAGEOUS EFFECT

A >2.8 fold reducing miniaturisation of the recovery process by gyration and customisation: By refining the method, process and use, not only was a >2.8 fold reduction of copper resource feasible, any small refinement would accelerate efficiency of purpose, preventing recurring losses.

The method offers solutions where others have not.

The proposed compact waste heat processing design overcomes: 6 out of 7 perceived Technical Problems

(Reported on page 1)

8. Importantly item 4; Inadequate response time for short burst use and 5; Existing art won't work well with low water pressure systems, where in older housing stock, the highest savings potential exists.

Heat recovery from high frequent short burst use of hot water spillage, such as from a hand basin or sink has the most significant potential, because the quantity of energy and water spilled often outstrips the actual use. This spec offers a compact Fig.l&2 method and system that suits in-floor or under-floor installations Fig.3, used for quick response delivery of waste heat from domestic applications using a moulded routing system a shallow rigid close-wound copper spiral C in a moulded outer shell HE, that intersects a horizontal drainpipe (item 1 ,15) like an inspection joint Fig.3, shaped and equipped with an internal spout (item 6), for boosting flow momentum and to generate decreasing or increasing cycles of the spillage selectable to equal or outnumber revolutions of the medium flow, on a shallow heat transfer processing platform C.

Guides (item 7) and transposable connections (item 9-1 1 ), manipulate the flows to match peak performance to specific flow demand (Table 1.2) DESCRIPTION OF THE INVENTION

The following description presents the invention in relation to preferred embodiments of the invention, namely a waste heat recovery system having a horizontal exchanger for the recovery of heat from waste water discharged from households and commercial businesses.

The invention is in no way limited to these preferred embodiments as they are purely to exemplify the invention and possible variations and modifications are readily apparent without departing from the scope of the invention.

In a first aspect, having aimed for domestic showering, the device is shaped and sized to return peak thermal power at 9 litres per minute, halfway the recommended or mandatory capacity range of 5 to 13 litres per minute processing. The cut-away section of the 40mm diameter drainpipe the shell intersects with = ±280mm. The diameter of the processing platform = 210mm and the processing volume (Fig.3-HE), of 1.9 litres more or less.

Overall throughput capacity is >30 litres per minute for flushing the end-use fixture, without overflowing the spillage nor trapping air. To achieve this with drastically reduced resources, performance critical attributes are employed, which are referenced and prefixed with a Category number and elaborated on under the heading 'Detailed Description of Attributes for heat recapture' and 'Substantiations. '

§ 1 The heat exchanger (HE Fig.1 -3), as described in claim 1, is preferably housed in a shallow walled containment designed (See Cat. ]) to intersect a substantially horizontal in-floor section of a drainpipe, which containment assembly includes a shallow walled moulded top T and a shallow walled moulded base B containing a close wound platform C for heat transfer, both joined by sealing flanges and include; the top T having integrated an upstream extension, outwardly projected (Fig.2) socket, connectible to the drainpipe for taking control of run-off angle (Cat.3) and turbulence and ensuring a flow steadying zone prior to receiving the spillage (1 ) and from which the downstream moulded penetration (Cat.4), extends inwardly as an internal re-routing (Cat.5), and spout (Cat.6), system, (See Cat.2 to 6), taking behavioural control of the flow and angled to direct and spout (6) spillage at intensified flow momentum, for delivery to the base (ii) B and; the base B, with a split level floor, the upper smaller floor of which is halfway up and being outwardly projected (Fig. 2) and enclosed as a pocket (Cat.8) for preventing spillage stratification whereby the lower main floor is concaved and bounded by a perfectly circular wall to snugly nest a close wound medium conduit C that extends the spillage pathway (1 ,15) to a centrally integrated exit and spigot, connectible to an external drainpipe for expelling the heat starved spillage, wherein;

111. a conduit (ii) C (Cat.9-11) to transport the heat transfer medium fabricated in a rigid close-wound coil to assume the snug fit of all of the said main floor (ii) of B, thereby providing a maximum gravitation processing platform, circular for inviting gyration of the spillage and optioned with variable guide means (7) (Cat.7) for regulating a thermal power band without increasing the medium's internal contact area for heat transfer relative to the proportional constraint attribute (iv) (Cat. 1), whereby the tubular conduit C receives the medium cool (9 or 10 or 1 1), while expelling pre-warmed supply (1 1 and 10, or 9) to the cold inlet of a hot water end-use fixture; iv. a singular sealed outer shell (HE) resembling a drainpipe inspection joint (12) (Cat. 12), formed by both the top assembly (i) and base assembly (ii) to provide an interior shape, space and means for two or more bulkhead penetrations for transposable connections (9, 1 1 , 14) with said conduit (iii) to create the basic apparatus, adept to the smooth routing function of a drainpipe (Cat.2) and sized by using a critical radius to best gyrate a liquid spillage (Cat. 1) into substantially horizontal and predominantly parallel flows for full and repeated contact for heat transfer, with the critical radius being a function of the viscosity and/or density and momentum of the spillage, and including ail of the dependent variable attributes stated (Cat. 1-12) herein, for customized applications, to help ease spatial restrictions and help prevent recurring internal and external losses associated with current art universal over-design.

§2 The heat exchanger as described in §1, from which the recovered energy is deliverable directly from the heat transfer medium C to the cold intake of the hot water source for replenishment. (Cat.1)

§3 The heat exchanger as described in §1 , wherein the spillage (1) is water. (Cat.l)

§4 The heat exchanger as described in §1 , wherein the heat transfer medium is water. (Cat.l )

§5 The heat exchanger as described in §liv, wherein the design process capacity and peak performance of the apparatus is determined from the point where equal velocities between spillage and medium meet, measured at the interior wall of the outer shell and the peripheral coil of the conduit, for a dynamic and prolonged molecular exposure, to determine the range of thermal power parameters. (Cat.l) (See 'MODE'), Page 6 line 1 1

§6 The heat exchanger as described in § 1, wherein the design process capacity versus best performance band width of the apparatus and its response time for delivery of the recaptured heat, is determined from the point in a thermal picture, where resistance for heat transfer begins to dominate. (See 'MODE') (Cat.l , 9-1 1)

§7 The heat exchanger as described in §1, wherein the predominant parallel flows (l iv) are in the same direction. (Cat.l at low demand flows, Cat.2-6, option of Cat.7, 8 and external connecting mode Page 8 line 30)

§8 The heat exchanger as described in § 1 , wherein the predominant parallel flows (l iv) are in an opposing direction. (As §7, external connecting mode transposed 9, 10, 1 1)

§9 The heat exchanger as described in § 1, wherein the predominant parallel flows (l iv) are both in the same and opposing directions. (As §7or §8, all flow demand, low pressure and third connecting mode Cat 2-1 1)

§ 10 The heat exchanger as described in § 1 , wherein conduit features, away frorh the processing platform (l iii) produce helical flow from the predominant parallel medium flow (refer 'BEST MODE' Page 15 top) § 1 1 The heat exchanger as described in §1 , wherein the guide means (l iii) extract marginal downstream cross flow from the predominant spillage flow. (Using or not Cat.7)

§ 12 The heat exchanger as described in. § 1, wherein centrifugal force extracts marginal upstream cross flow from the predominant spillage flow. (Cat.l & Cat.7 variation four mm or two mm, in higher demand flows) § 13 The heat exchanger medium conduit, as § 1 , wherein the medium conduit C is fabricated in a double wall construction format. (Mode)

§ 14 The heat exchanger in-service access (12) Fig.3 as described in §1, wherein access to the processing platform (iii) for in-service inspection is provided by a made to measure shaft, connectible from the shell top (i) T to an access facility above, or any other practical level. (Cat.12) § 15 A heat exchanger as described in § 1 , having its components specified to be of adequate heat resistance for applications using liquids in a varying state, which typically and specifically for sanitation run-off in liquid or vapour form, complies with field mandatory safety standard(s).

From this 9 litre per minute design above, a wider range of flow demand from 5 tol 3 litres per minute is provided, without increasing the medium's internal contact area for heat transfer, a slower and a faster model are proposed for customization and assembled, to each achieve a peak performance of heat recovery, fine tuned to the user's demand flows (Cat.l) and supply system characteristics. (Mode)

§ 16 A heat exchanger as described in §1 , including any derived method of providing for two or more substantially horizontal and circular pathways for heat transferring exposure by clockwise or anticlockwise gyrated motion inside a drain vessel, wherein waste heat carrying liquids are processed in varying state, viscosity, density and flow momentum using a direct or indirect medium in varying state such as refrigerants, which method defines the space, shape (Cat.l) and routing (Cat.2-6), interpolated or extrapolated as defined from a critical radius to best gyrate that liquid into substantially horizontal and predominantly parallel flows with the medium, for prolonged and, and/or repeated contact for heat transfer, wherein some or all attributes (Cat.1-12) are employed and wherefore suspension means include a gimballed suspension and applications may span from single and zone shared or reticulated sanitation, to storm water, motor cooling or industrial run-off systems.

§ 17 A heat exchanger system application method as described in § 1, providing in-service access for remote flushing and monitoring, so practical and mandatory durability requirements are met. (Cat. 12)

§ 18 A heat exchanger as substantially hereinbefore described with reference to the accompanying drawings. Figures 1 to 3, labels HE, T, B & C and 1 to 15 § 19 A heat exchanger system application method as substantially hereinbefore described with reference to the accompanying drawings. The heat exchanger in the example, due to its compact design, features a significant low flow resistance or internal pressure drop, creating incremental options for functioning with low pressure systems. (Using or not Attribute Cat. 9)

Accurate levelling, suspension and in-service access to the apparatus's interior is inclusive of this spec. To ensure best performance, while improving comfort levels for the end-user for not having to readjust the flow mix, the narrowest practical demand flow setting will determine how quickly pre-warmed water can be . supplied to the end-use fixture. Category 1 attribute is the end-user input. Cat 2-12 the assembly of a responding apparatus and its use.

A Detailed Description and Attributes for heat recapture

Performance critical attributes (Elaborations)

A method for use is now detailing the design attributes with references to the categories marked under the category numbers (Cat.#). The heat exchanger. HE ⁷ for the recovery of residual heat from drainpipes, which intersects a horizontal drainpipe, needs a steadying zone prior to spillage intake and is specifically shaped, equipped and critically sized Fig.3 (Cat.1 ,2 and 1 1) to gyrate ² the liquid spillage into substantially horizontal and parallel flows Fig.l -(l) for heat transfer and expose the excited molecules in either co-directional flows, for prolonged exposure, or reverse flow, in multi-cycled encounters, or to gyro-cycle ³ , a variant of the two options in faster flows (Cat.7), whereby after first exposure, some spillage molecules are centrifugally remixed with the most excited molecules upstream of the spillage and get to meet refreshed cold ones of the medium in both parallel flows at the same spot again, a process for which the circular shaped C exchanger is snugly housed in a critically sized circular and shallow T & B outer shell Fig.2.3 that provides the interior space and shape and smooth internal routing spout system for the spillage Fig 2 (Cat.2-6) and projected means for preventing stratification (Cat.8), and guide means (7) to lead and extract cross flow from the dominant parallel flow of the spillage (Cat.7) and for selecting the number of gravitating planar revolutions of the spillage without undue head pressure and to provide smooth routing over the conduit C, whereupon heat transfer takes place before expulsion (15) of the heat starved spillage, which expulsion is tied to a specific process application (Cat.l) and critically timed to take place before resistance to heat transfer dominates and which accommodated heat exchanger conduit C has an attribute for rapid external delivery of the heat enriched medium (Cat.10) and the combination of means (Cat. 1 -1 1 ) for refinement of control to widen the thermal power peak over a range, at the time of installation, before and after, without increasing the medium's internal contact area for heat transfer and has a means of in-service access ( 12) (Cat.12) resembling a pipe inspection point to maintain same peak performance and the interior shell space T & B to provide more than three times the peak power flow rate for spillage throughput capacity (Cat. l ), which heat exchanger HE, outer shell, its means of connection 1 & 15,

¹ Numbers and Capital letters refer to corresponding markings in the drawings

² Gyrate as in a spinning motion with an off centre vortex, powered by the liquid's momentum.

³ Gyro-cycle describing a motion between whirlpool (inward) and turbination (outward and without the scoops,). 9-1 1 , suspension and customizing attributes (Cat. 1-12), help ease spatial restrictions and help prevent recurring internal and external losses as associated with universal over-design.

The heat exchanger system design achieves miniaturisation, by having a configuration composed of up to 12 internal and external dependent variable attributes, a formula devised to re-produce competitive returns for wider applications, which attributes are categorised as;

Category 1: Prelim inary input from application purpose to determine the parameters for processing spillage and medium conduit capacity;

Cat. 2 to 6: Respectively; Fig.3 spillage (1) pipe size (2) + run-off angle (3) + redirection angle (4) + momentum angle (5) + angle of delivery of spout (6), as detailed in Fig.3 and below, or otherwise determined by spillage viscosity.

With specific respect to showering, the shell preferably has the following spec;

Receiving spillage via a >300 mm external steadying zone at 3° design run-off and matching the size of the external feeder pipe at 40mm nominal diameter, begins routing of the flow using a 64° design radius left Fig.3, (or right if the process is mirrored), curve aside for smooth redirection and 15° design mn-off to intensify momentum and delivers the flow at the acute angle of >0 and <10° Fig.2 to the internal wall of the process shell, to the conduit outer surface. (Cat. 2 to 6)

The heat exchanger medium conduit C comprises a close wound, dished, rigid fabricated spiral , taking up all of the dished and circular shape of the lower part of the shell, both inviting an unpressurized whirlpool like motion from the turbulent spillage as it spreads and circles onward from the spillage spout control (using Attribute Cat. 2 to 6), over the conduit and, with the additional control of guide means, (using Attribute Cat. 7 & 8), for assisted and quality assured parallel flow, co-inviting with the spout control, marginal upstream cross flow for high velocity spillage, or downstream for lower loads before expulsion via the central spillage exit.

Cat. 7: Guide means (7) of a size, in ratio of vertical protrusion to spillage demand flow; i.e. 4mm high for 9 litres per minute, if water, over a <210mm rotating pathway, or 6mm high for 6L/min. flow, or 2mm high for 12L/min. flow.

Cat. 8: The pocket size in extreme dimension relative to shell internal diameter, r = 148.5 : r =105, if water, or otherwise as determined by viscosity. ^'

The shell also integrates this attribute for manipulation of the spillage flow, and, if water and in the first aspect, by having at 352° (fig.2) from the spout (6) tip, one sector of the curved wall of the outer shell interrupted to outwardly feature an isosceles triangular pocket with a raised platform that prevents undesirable flow stagnation and stratification. (Cat. 8)

Other attributes as required prior to assembly of the product;

Cat. 9: Re-feed (9) connection ofjhe medium, as determined by (Cat.1) + low line pressure, Inlet connection or re-feed Fig.3 is an optional connection for the heat transfer medium that enables control to match the medium to spillage velocities for effective heat transfer, increased temperature differential and reduced pressure drop. In other words inlet connection (9) allows for connection to a smaller diameter tube for use in wider range of flow demand.

Cat. 10: User input as required to determine the conduit size, and internal contact area, containing 4.22 m coil length to 210mm heat transfer platform or 0.1043 - 0.1056m ² internal contact area : 0.210m' diameter.

The heat exchanger medium conduit C, as in the first aspect scenario, having the conduit fabricated using a high velocity, pipe size of 10mm, EN 1057 Type B and small winding radius, for exploiting the highest feasible drag for optimal heat transfer. (Cat. 10) The smallish tube thus allows a more compact processing platform ^' that e.g. fits between existing floor joists. It also allows for a larger contact area proportional to fluid displacement and produces better turbulence for higher heat transfer.

Cat. 11 : Shell process Fig.3 volume for flow rotations relative to its momentum at 40 : 210 (with Cat.2);

The heat exchanger medium conduit C, wherein the achievable shortest process cycle of the heat transfer conduit ensuing from Cat. 10, enables further shortening of that heat transfer conduit, reducing cycle time and pressure drop, so that the said outer shell interior meets the volumetric design target of <1.9 litres more or less, (Cat. 1 1 )

Cat. 12: In-service access, for maintaining the performance peak.

The heat exchanger in-service access, (Fig. 3), wherein the capping and shaft ( 12) representing the in-service access for inspection, flushing and retrievals, is preferably an optional made to measure shaft, stench free capped and sealed to withstand stresses to<85kPa, which shaft is connectible from the top of the shell to an access facility above, to any other practical level. (Cat. 11)

Attributes that assist best performance and remain changeable for altering demand flows with use of the device;

The heat exchanger medium conduit body, with which optimum transference is enabled, is externally co-promoted by; '

a) From (1 1) to Mixer, specifying equalizing velocities; e.g. conduit flow = 25% of the spillage flow, (using Attribute Cat.1), or;

b) From (1 1) feed to HW fixture specifying polarised velocities, i.e. conduit flow to = 100% of the spillage flow, (Not using Attribute Cat. 1), or;

c) by halving medium velocity of both, i.e. specify internal cold re-feed (9), (Cat. 9);

d) preferably by user input prior to product assembly, (Cat. 10), matching the desired peak performance fix.

(Using Attribute Cat.l and 7).

e) preferably providing in-service access for performance upkeep. (Cat. 12)

f) providing in-service access for remote flushing and monitoring so the utmost practical durability requirements are met.(Cat. 12)

Manufacture and installation follow known methods and code of practice' associated with the UPC, IPC and HVAC industry. Installation

The waste water heat recovery system when factoring-in for purpose design, may encompass as many as 5 flow rate categories within NZS4305 at 5 group levels of supply line pressures in 4 different service configurations.

A survey on domestic hot water use in NZ, namely HEEP 2006, gives a reduced pressure showering mean flow demand of 7.2L/min. and 10.5 for mains pressure users, suggesting 3 flow rate categories may suffice.

Installation of the waste water heat recovery system essentially involves interrupting services and. inserting the unit(s) into the fixture's waste pipe and the water supply connected to feed either the hot water source facility or fixture mixer, or both. It may be placed anywhere from 300mm or more, horizontally down line from the waste trap. It is to be carefully levelled, secured and maintenance access provided. Coil connections must be of the flexible braided type to absorb water line hammer and follow the client's purpose designed configuration. On commissioning, a visual inspection guides a levelling fine tuning operation in which the waste flow should cover >95% of the spiral at 5L/m. A floor inspection hatch access is recommended. If used with a strainer for larger particles, maintenance frequency will not be different from that of a strainer as explained in a user guide.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described, by way of example only, by reference to the accompanying drawings:

Figure 1 shows the preferred whirlpool motion, a simplified representation of the principle motion produced by the waste water heat recovery system in accordance with the embodiment of the invention. 1 is the spillage, 6 spout, 15 drain, between 10 and 11 is the medium conduit C, which forms the processing platform.

Figure 2 shows a perspective of the exchanger HE as prototype IV Mark 5 for simulated tests on domestic showering. (Refer 'Substantiation')

It depicts the, Top T, coil C and Base B. The base shows the sealed flange arrangement.

Bulkhead penetrations serve the connections 9, 1 1 and 14.

Together with critical factoring of the flow density and velocity, transference is changed by the very presence or the height of ^" the guide means 7, to find a targeted performance range. . This is explained in more detail in 'Detailed Description of Attributes for Heat Recapture' and later under the heading: 'Mode for Invention.'

Figure 3 shows a vertical, cross sectional view of the exchanger HE, shown in accordance to a preferred embodiment of the invention. The spout is 6, the close wound conduit C, spillage processing platform C and guide means is 7.

Substantiations

In preamble to this Final Specification, below is a brief history of the development of 'Miniaturisation of Process'.

Competing with one design fits all purpose. By refining the process and use, not only was a >2.8 fold reduction of resource feasible, any small refinement would accelerate efficiency of purpose. The task set was to find the 'fix' plotted between heat transference and resistance to transfer for demand flow rates in a practical application.

The application target range became that described in AS/NZS6400 and NZS4305.5.2J & 2 and set at 9 L/min., midway the recommended flow rates of 6 to 12L/min. (Cat. l)

Testing pointed to a system enabling co directional flow in parallel. With a focused planar orientation, spatial restriction and given temperatures, some degree of prolonged exposure needed to be found to reach a contextually best level of thermal returns. (Cat.l)

This was found using a circular shell shape, spout system (Cat 2-6, dished platform) and whirlpool spillage motion of 1 to 1.2 revolutions at 5L/min. On a tubular tightly coiled surface this meant severe cross flow occurred.

Reversing the medium flow, stretching the temperature differential, improved the rate of recapture and produced a best of 7-8°C between heat starved and pre-warmed flows. A tandem hook-up improved this to 3-4°C.

On that circular conduit surface it was found that low density spillage would marginally tend to cross-flow down to the centrally positioned exit. However, the spillage behaviour was fickle, particularly, if the processing surface was not horizontal. ·

After controlling this behaviour with guiding means (Cat 7), it was discovered that the peak return increased to 6L/min. Now parallel flow was controllable, nearing the target and repeatable.

By lowering the height of the guides, flow could be increased without causing stratification after also overcoming stagnation of the spillage flow after nearly one full revolution. (Cat. 8)

During that experiment, it was observed that at the higher demand flows, above 7.5L/in., the spillage had the opposite tendency by marginally cross flowing away from the central exit. As is explainable by centrifugal force.

This offered more means to manipulate the spillage to medium exposure from 1 complete revolution to 7 times or more, on the same sized processing platform, achieving peak return at 6 as well as at 9L/min.

The time weighted exposure for low flow demand and the temperature differential weighted exploits dominating at high end, could now be switched or mixed, by introducing a third connection, or re-feed, of the medium. (Cat.9)

By varying the guide height and transposing supply for the medium, peak performance was stretchable over most of the sought range of 5L/min. to 9.5 L/min. after which the curve declines and. at 12L/min drops steeply. (Please also refer 'Definitions').

This range shows the best performance versus flow capacity fix at 9 litres per minute

This is achievable with the pre-warmed flow feeding the mixer cold intake at the rate of 2.3 litres per minute, (Cat.

1), provided that the 4220 long, close wound spiral conduit is fitted with 2415mm long guide means, (Fig.3) protruding 4mm straight up from the conduit's upper surface, for control and assistance to the flat rotational motion and marginal cross-flows. (Cat. 7) (See also 'Mode of Invention'- Field testing).

The curvature of the outer shell, density and viscosity of the spillage, inextricably govern projection to different applications.

Where the spillage flow path velocity was a function of the targeted capacity range and curvature of the outer shell, the known velocity of the medium needed to be calculated into a pipe size. In this case, 10mm nominal size pipe responded to this need. (Fig. 3) (Cat.10 and 1 1 )

Inside that copper tube, the medium experiences intermixing turbulence brought about by the significantly higher drag of the small tube diameter (Cat.10), relative to the size used in other exchangers relevant to this application.

Cleanliness during use of this exchanger determines efficiency. (Cat.12) In-service access is featured. Access also allows accurate levelling on commissioning.

The system was found to function with >95% of the processing platform covered by spillage flowing via a critically routed spout over a rigid close-wound conduit, horizontal, perfectly circular and dished to provide continued gravitational run-off. Compact, quick response processing for Domestic Hot Water was proved to be feasible.

This performance level status is identified as prototype 4 Mark 5 (Fig.2).

Table 2.2 Test Readings II

POWER Saved in Watt/hr/Ltr/ldegr.differential HB single gate, tandem module Shower Simulation l W _i ° D _iff tt _dt aaavne _{re i} e _i,,,

a

E 6 0 9

|£ Liters per Minute, feed Source + Shower Mixer

D'C spillage ■W/Ltr/1 ^' Cdiff 0% spill saving

POWER Saved in Watt/hr/Ltr/1degr.differential HB double gate, single module Shower Simulation

45.0

40.0

35.0

30.0

25.0

20.0

15.0

10.0

5,0

5 0.0

a 7.5 0 9 E Liters per Minute, feed HW source

O'C spillage "W/LtrfrCdiff ^Q % spill saving

Saving Potential Indicators

Table 2.1 shown above, lists variations for showering solutions with relevant parameters and performance data collated from simulated tests and shows 10 extracted test result from Table 1 (Not included) for thermal power work out.

Table 2.2 Shows three graphs extracted from 2.1 . Test protocol, conditions and meaning are below. Definitions

Despite the lack of an international norm for benchmarking and testing protocol of devices for heat recovery, the thermal power saving outcomes for the herein proposed design range can be reliably evaluated from their respective variations in percentage saving of heat.

All reported values are readings from domestic shower simulated tests, their perceived typical use in seasonal averages in mild to moderate frost zones and as described in NZS4305.5.2.1 and NZS4305.5.2.2: Accuracy tolerances are in Table 2. Data Spreadsheet: 'Test Readings.' The conduit for the heat transfer was a B280 type L copper with a 98-100% IAC conductivity spec. Conducted test results mean: (ΔΤ recovered x 100)/ TT spilled = % Energy saved

Savings mean: Saving of energy to be replenished to perform the same task.

Conditions: All values assume same set of Conditions, except:

§ Ambient conditions.

Density (temperature differential and flow rate). This varies between readings. Precise data for temperature differential are given in the Table 2 column termed: 'Spilled' or the delta symbol 'Δ inverted'.

§ Mark 1 to 5 Prototype Modifications. Where values are referred to early prototypes, later improvements were not interpolated or extrapolated. Data in Table 1 differentiates these outcomes.

Where mixer fed configurations are stated: (I.e. Coil feeds cold intake of mixer) the coil or Medium flow = 25% of the spill flow or Waste water flow. In practise this may vary more widely depending on the type of hot water source.

All the saving values given are measured at the processing shell entry or exits and exclude losses of pipe runs. Data come from 1 st cycle only simulated test readings.

At a flow rate midway those stated in NZS4305 and AS1056, or at the maximum in Federal Energy Policy Act 1992, the best repeatable single module performance result for heat transfer is formulated as:

(The reading is for a mixer fed simulated shower test at a perceived mean Density of 32.7°C at 9L/min.):

Q = UA J T or:

1103 = 323.4 . 0.1043 . Where U = OHT coefficient in Watt/mVC (Surface heat transferO

A = Area for heat transfer, here given as inner contact area in m ²

T T = Temperature differential of spillage and medium in °C

Q = Amount of heat transferred in Watt (The actual value from test result)

(U value = 81-87% of the copper HT Coefficient in physics. Refer 'Limitations').

In plain terms the above value pertaining to the same test result, saves 42% of energy. A tandem arrangement, using 8.4m of pipe, can boost the rate of saving to 60%.

The peak performance range is selected to match NZS4305 domestic flow rates intentions of 6 to 12L/m. for shower use. The mean actual rate, reported in BRANZ HEEP 2010 appears 10.5 L/min. At 12L/min., savings are at 37%.

In 'Mode and 'Best Mode', a performance value is used for easier comparison before and after. I.e. the U value - 81-87% of the copper HT Coefficient in physics. The value accounts for the inner contact area only. Therefore, the comparison is externally biased, as the full effect of tests involving the outer transfer area with the guides was unavailable at the time of print. This awaits Mark 6.

Compliance Under NZBC G12 and if this device is used as a direct exchanger with potable water and of single wall construction, the High Hazard Classification applies. Backflow prevention devices must be installed.

Not all jurisdictions allow a single wall design, unless used as an indirect system. Other territorial and / or central safety regulations may need to be followed. The heat exchanger system designs as described, having preferably the exterior shell wall isolated to reduce heat loss from external evaporation and insulated for frost protection.

A heat exchanger system design as described above, durably operates where the SWP or internal stress of the medium conduit does not exceed 6000kPa and that of the inspection joint does not exceed 85kPa if targeted at typical sanitation systems. ■ ^■ ; ^■ .. >

Australasia

On compi ling this report no other equivalent Norm to New Zealand Standard 4305-1996, (Australian S1056 Minimum Energy Performance Standard 'Hot Water Supply Systems,' was found online in English for other jurisdictions. This regulates flow rates for domestic shower use. Hence the use of this tool.

Furthermore Australia is perceived as the master of water preservation, setting the benchmarks; AS/NZ6400-2005 Water efficient products and A NZS3662 Performance of showers for bathing.

USA and Canada At a 42% saving (of 0.44kW per shower at 9L/m or 2.37GPM), the design load for peak performance of the HB exchanger is ideal for aligning with the Federal Energy Policy Act of 1992 prescribed flow rates of 2.2-2.5 GP . (See also l rst paragraph)

UK and Europe

As the waste water heat recovery system is aimed at wide spread use, the range of targeted flow rates is a trade off between recently prescribed NZ rates in NZS4305, A/NZS6400, AS1056 and USA FEPA 1992 and the need to cater for low pressure systems which perceivably represent the largest group where retro fitting is needed. BS and EN Standards or Norms appear under review. Discussion papers, BNWAT06 and BNWAT24 also mention A NZ6400 for guidance.

Existing British (BS6340-4) and European Standards are under review.

Refer BNWAT02, 04 and 24

Refer EN 13904- 2003 and EN 1 1 12-1 997

BEST MODE for carrying out the invention

1. Before production status, field tests and accelerated fouling test are to be conducted, to resolve issues of tolerance, durability and Quality Assurance.

2. On production, three additional Heat Transfer issues toward enhancements and repeatability of HB Mark 6 and onward, is planned. This is believed to add a conservatively estimated overall 3% to the energy saving values of the direct exchanger. Substantiated as follows: (Refer records in Table 2.1 'BEST MODE')

Critically controlled stress ^' relief of the assembled spiral.

A higher silver content continuous soldering of extended Heat Transfer contact area of the spiral in mark 6.

Projection is 4% by outer HT contact area.

Reduced external evaporation heat loss is next to being harnessed in the ultimate choice for the injection moulded material of the processing shell. The reduced loss of transfer is projected at 3%.

3. Another improvement for the exchanger is the selection of the more appropriate helically ridged tubing instead of the pipe approved for potable water. Here projected at 10% improvement, which can on sufficient demand be applied to indirect exchangers. Substantiated as in Table 2.1 Internal helically ridged copper tubing such as Wolverine TurboDX, suggesting an improved Heat Transfer Coefficient of up to 50%. This awaits potable water code compliance procedures.

From the above, the ultimate product's U value of the heat transfer equation, as stated and described as being 81- 87% of the copper HT Coefficient in physics, (Refer 'Definitions'), is envisaged to rise to 83-89% for direct applications and, is projected to increase to 93% for indirect configurations.

§16 A derivative heat exchanger system direct or indirect application method, preferably as specified in claim 1 and 16, being a method for use in wider applications, is included for best mode R&D. Benchmarking these modes seem harder as densities vary. § 13 A heat exchanger system design as described above, having the HT conduit fabricated in single or double wall, using a high velocity, code compliant, lowest mass and small winding radius pipe or channel composite, for exploiting the highest contextually feasible drag for heat transfer. (Cat. 10)

A heat exchanger system design as described in claim 1 to 27, whereby the Safe Working Pressure or internal or external stress of the medium conduit exceeds 6000kPa and that of the inspection joint exceeds 85kPa if not targeted at typical sanitation systems.

MODE FOR INVENTION

The design brief has centred on the size of application restrictions to encourage engagement in reducing wastage.

When modelling thermal and water wastage on average NZ electricity only using households, 35% is spent on DHW. 10-15% of that bill was immediately and easily recoverable from actual use alone, and also improving user comfort by shortening response time. Now targeting existing houses and bundling this activity with in-sync downsizing of pipe runs, 25% of DHW power, C02 and 13% potable water savings can be achieved for up to 75% (pre 1978) of the NZ housing stock. One of the embodiments of the invention includes the Heat Exchanger is applied with Domestic Hot Water as depicted in Fig. 1 & 3 and is described below;

From simulation tests this range shows the performance versus flow fix at 9 litres per minute, Table 2.2 lower graph, which is midway the recommended flow rates in AS/NZS6400 and NZS4305.5.2.1 and 2. This is best achievable with the pre-warmed flow feeding the mixer cold intake at the rate of 2.3 litres per minute, (Cat. 1), provided that the 4220mm long, close wound spiral conduit is fitted with 2415mm long guide means, protruding 4mm straight up from the conduit's upper surface, for control and assistance to the flat rotational motion and marginal cross-flows. (Cat. 7)

This compares for best thermal power efficiency with other flo rates within that range at a ratio of 40 : 42, or 95% relative to that produced by the 9 litres per minute configuration, if the spillage flow is restricted to 6 litres per minute and the protruding height of the guide means measures 6mm ⁴ .

The best ratio of 37 : 42 or 88%, featuring a protruding height of 2mm, if the loading is 12 litres per minute.

A tandem arrangement prevents the relatively steep curve fall implied above, and produces a 60 : 42 or 143% best return.

Detailed test results of the design applications are given in Table 1 and 2. Test protocol, conditions and meaning are given under 'Definitions.'

The exchanger is housed in an outer shell, preferably having a design volume of 1.9 litres more or less, with capacity for 5 to 13 litres per minute spillage processing in critical proportion to processing platform

Tolerances for guide protrusion are set by field testing outcomes diameter of 210mm and a 30 litres per minute, all inclusive capacity for flushing the fixture and platform, without overflowing the spillage nor trapping air.

§4. The exchanger preferably having its peak thermal power at mean usage demand flows at selectively 7, 9 and 10.5 litres per minute over a processing range between 5 and 13 litres per minute if the spillage is water. (Cat. 7)

The Key Area of Advancement:

See also the shell and conduit dependent variable attributes for control options (Cat.1 -12)

The use of this method enables miniaturization, providing practicality as explained below;

For good results, it is essential that all items 1 - 4 are applied.

1. A whirlpool and gyro-cycling motion. Refer also §1 and 'Description of Drawings.

In parallel co-directional flows, both spillage and medium velocities can be matched for whirlpool like time weighted exposure.

With opposing or mixed flows of spillage and medium, the whirlpool solution uses the waste flow momentum to effect a multi-pass process of heat transfer for both the waste and the medium flows in a horizontal plane.

Under higher flow demand, critical dependent attributes (Cat. 1-12) produce a marginal upstream effect that can be applied to both matched and reversed parallel flows. Because this is powered by centrifugal force it is conveniently called gyro-cycling. Within the range of domestic flow rates this must be at least accompanied by the attributes 2 to 4 below;

2. Reducing the tube diameter.

The smaller size widens the velocity range, offering heat rise and/or increasing time factor weighting for variable loadings, while providing for flow rates nearer to the (Building Research Association NZ) noise guidelines at two metres per second. This optimizes the medium's contact intensity for heat transfer by increased drag. (More in 'Detailed Description of Attributes for Heat Recapture' Cat.10)

3. Shortening the tube length.

While in fact shorter, the outer contact area for heat transfer is co-extended by means of a flow-specific variable copper strip that also engages the waste flow into parallel, predictable multi-passes and flow-specific co- directional motions, resulting in better performance of transference relative to coil length.

This further contributes to miniaturization, shortens response times for short burst usage of a hot water fixture and helps to quickly stabilise and prevent the need for temperature readjustments during e.g. shower use in more efficient exchange-to-mixer configurations.

4. Factoring user input to maximize performance.

Refinement and tuning options for various line pressures, velocities, transference contact time and installation spaces. The compact horizontal process chamber, containing the copper spiral exchanger, features the medium spiralled with, not around, the path of the waste flow. Preset procedures from tested precedents projected within the user-specified flow demand, provide choices of:

4.1. Coil re-supply connectors, enabling purpose design to suit the supply line pressure in focus and select: 4.2. Low flow ranges, allowing hot and cold molecules to spent more time together, or

4.3. A focus purely on temperature differential as the main factor for recovery in higher fixture flow situations. The above solution, comprising item 1-4, requires managing and factoring the flow and heat level density, the fluid velocities, the number of passes of the flows and partial compensation for reduced heat transfer area relative to traditional systems.

Together with the options for the very presence ⁵ , position and length of the flow guides, this enables manipulation of the number of fluid passes, relative velocity and parallel up or down flow directions of the medium. Upon installation this can be enhanced with additional or changeable control and connection options. Refer 'Detailed Description of Attributes for Heat Recapture' Cat.12)

For field testing only; At 100- 120mm before touch down of the waste flow, the waste entry pipe, at the plan view angles shown, is to incorporate a standard radius waste bend of 40 x <22.5° enabling adjustment from a 3° waste pipe run off to a preset 15° momentum assisted fluid transfer while curving to the left into the process chamber. This to ensure waste flow disturbance is corrected to a stable repetitive pattern.

For field testing only; The exchanger spiral is then to be fitted with a 241 x 8 (+2-0) x 0.55mm copper sheet metal strip as the guide and extended contact area. The guide's position must follow that laid down in Figure 2 & 5 and be continuously, (high content silver and lead free), soldered to the spiral with injected (air free) paste solder. Variations - The latter strip height applies to demand flow rates to 7.5L/m, beyond which the height of the guide must be reduced to 8(+0-2)mm. and below which the height and tolerance may be widened to 10(±2) For example, at the given 7.5 L/m flow rate, the critical factor is for the guide to be a maximum of 4 mm above the spiral otherwise stratifying and partially stagnant waste flow will occur. This feature was only tested up to 12 LYm, beyond 12L/m a tandem configuration should be used to bring the velocities within design range.

Current incomplete resources, yet essential for commercial use with the design comprise:

§ Accelerated fouling and scaling tests and chemistry / durability consultations

§ Field tests, in direct and indirect mode

§ Life Cycle Analysis and Environmental Impact

§ Frequency of in-service monitoring of performance for user guidance

§ User input gathering, Installation and Configuration guide

§ Temporary transport resilience specification

§ Expanding product application(s), e.g. Increase Heat Resistance

§ Manual or automated reverse flushing from the exchanger's antifouling pocket

INDUSTRIAL APPLICABILITY

Heat recapture from hand washing, showering, hot water rinsing or steam cleaning are primarily focused on, especially by communities in temperate climate zones, who would stand to gain most.

⁵ Applications for flow demand <5L min. do not require flow guides. The preferred embodiment especially suit domestic retrofitting and include exchangers

configured to suit 2 types:

1. Direct exchangers: Simultaneous use and spill hot water fixtures such as shower cubicles, shower uses in bathtubs, laundry tubs, rinsing facilities, flushing fixtures in food processing spaces and milking sheds. 2. Indirect exchangers: (Demand unexplored) All other non simultaneous fixtures and appliances that may be connected to secondary Heat Transfer coils, such as in conjunction with heat pumps or indirect solar heat collectors. In general, these devices are applicable to all entities and situations where there is a concern with energy usage, emissions and reduction of demand for potable and non potable water. Direct and indirect systems work with any known type of hot water systems.

If any of the applications is exceeding a demand flow of 13 litres per minute, tandem arrangements may provide extra capacity. Otherwise larger versions are needed (§16).

In jurisdictions not allowing the use of small pipe sizes, a second module may be installed.

Variations

Throughout the description of this specification, the word "comprise" and variations of that word such as "comprising" and "comprises", are not intended to exclude other additives, components, integers or steps.

It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is hereinbefore claimed in the following accompanying appended claims.