NZ250784A

NZ250784A - Shower system; heat exchanger fitted in showerbase extracts heat from waste water

Info

Publication number: NZ250784A
Application number: NZ250784A
Authority: NZ
Inventors: Donald Murray Clucas
Original assignee: Donald Murray Clucas
Priority date: 1994-01-31
Filing date: 1994-01-31
Publication date: 1997-01-29

Description

New Zealand Paient Spedficaiion for Paient Number £50784 250784 Patents Form No. 5 Patent No: 250784 Dated: 31st January 1994 Patents Act 1953 2 8 m ® COMPLETE SPECIFICATION HEAT RECOVERY SYSTEM FOR SHOWERS 3,-7 a I, DONALD MURRAY CLUCAS a New Zealand citizen nf J2S^_wwr<b&iii ..BiW- Christchurch, New Zealand, hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: 1 250784 The present invention relates to a heat recovery system for domestic or commercial showers.

In most showers hot and cold water are mixed to an approximate average temperature of 38-45° C. By the time this incoming water is used and reaches the drain from the shower unit in practice it has been found that it is down to a temperature of approximately 37° C. The temperature of the cold water used to mix with the hot water for a shower is of the order of 5-20° C. Thus it is apparent that either heating the cold water before mixing, or preheating the water entering the hot water heating unit, would considerably reduce the amount of energy required to heat the water required for a shower.

A known method of improving the energy efficiency of a shower is the use of a heat exchanger between the flows of waste water and the cold water, either to the hot water heating unit or to the cold water being mixed with hot water for a shower, or to both. The difficulties are obtaining a sufficiently efficient heat exchange to justify the cost, and finding the necessary space to place such a heat exchanger. The difficulties of obtaining a sufficient heat transfer area whilst complying with hygiene and cleaning standards have meant that no appropriate heat exchanger is known that can be used within the shower unit itself.

An object of the present invention is the provision of a heat recovery system that can increase the energy efficiency of a shower, provide an improved shower from direct electric domestic hot water heaters, and meet any standard hygiene and heath standard. A further object of the present invention is the provision of a heat recovery 250784 system that is simple to produce, can form part of a shower tray when produced (if desired) and/or is quick and simple to install and maintain.

The present invention provides a heat recovery system for domestic or commercial showers, said system including: a heat exchanger with at least one heat exchanging pipe therein with an inlet pipe and an outlet pipe, said heat exchanger being dimensioned to be capable of being fitted into a base of a shower; and outlet means for waste water; wherein said inlet pipe is connectable to a source of cold water, and said heat exchanging pipes are positioned across a substantial portion of the surface of the base of said shower.

Preferably, there are a plurality of heat exchanging pipes; and preferably said pipes are double flow pipes. Preferably the flat heat exchanger is blow moulded or press formed. Preferably, the shower base and heat exchanger are integrally formed.

The outlet pipe can be connected to either the cold water inlet for the shower head or mixer or the cold water inlet to a hot water heating unit of any known type, or to both.

Alternatively, said outlet pipe may be connected to the inlet of a further heat transfer system of known type, the outlet of which is connected to the cold water inlet for the shower head and/or to the cold water inlet for the hot water heating unit. Said further heat transfer system is needed if health regulations require the use of at least two separations between waste water and potable water.

By way of example only, a preferred embodiment of the present invention is described in detail with reference to the drawings accompanying the provisional specification, in which:- 250784 Fig. 1 is a partial plan view of a shower base of the present invention; and Fig. 2 is a partial section of a shower base of the present invention.

Referring to the drawings, a shower base 2 is thereshown. The shower base 2 includes the standard raised sides 3, a drain hole 4 (and rim 5) and a base surface 6.

Such bases 2 are commonly of stainless steel or other suitable, hygienic material, for example copper, moulded fibreglass, etc. A heat exchanger, in the form of a plurality of pipes 7 is formed in the base surface 6. The pipes 7 are interconnected, with an inlet pipe 8 and an outlet pipe 9. The pipes 7 are formed in a parallel pattern across substantially the length and breadth of the base 2 between the inlet and outlet pipes (8, 9).

Referring to Fig. 2, each section of pipes 7 is in two parts (7a and 7b), with a separating insulating strip 10 therebetween. This permits a double flow of water through the pipes 7. The separating strip 10 may be positioned only within each pipe 7 or may be a sheet spread within the mould (not shown) as the base 2 is produced, as is desired.

Each pipe 7 is shown as being flattened on the top and the bottom, in cross-section. However, if so desired, the cross-sectional outline of the pipes 7 may be any suitable cross-section (for example circular). In this sense "suitable" is used to mesa suitable for ease of manufacture, for ease of cleaning and maintenance, and for suitability for standing on or resting objects thereon.

The pipes 7 may be of any appropriate material (for a shower base) that is sufficiently strong and is a heat conductor. The most appropriate material is stainless 250784 steel which is blow moulded or press formed to produce the pipes 7. However other materials (for example copper) may also be used. A seam weld 11 between adjacent portions of the pipes 7 is also used. The arrangement of the pipes 7 is shown in Fig. 1 as a single pipe 7 between the inlet and outlet pipes (8, 9). If so desired, the pipes 7 can be arranged so that there are a series of parallel pipes between the inlet and outlet pipes (8,9), in which the water flows in series or in parallel. In practice it has been found that the water flow through a series of pipes 7 is the more efficient method of transferring heat to the cold water within the pipes 7. Alternatively, if so desired, the pattern of the pipes 7 may be other than parallel. For example the pipes 7 may be in a spiral pattern, when viewed in plari.

If so desired, the shower base 2 may also include a raised drain 4 with small holes 12 in the side of the drain 4 (Fig. 2). Thus the drain 4 acts as a weir, retaining the waste water adjacent the pipes 7 for a slightly longer than normal period, and increasing the efficiency of the heat exchange process. The holes 12 permit the total draining of the waste water from the base 2 after the shower is finished.

If so desired, a rubber mat (not shown) or other insulator may be placed over the pipes 7. This may be for the convenience of the user as the pipes 7 will feel cold to the user of the shower. If the raised drain 4 (as described above) is used, the use of a mat for standing on has been found in practice to leave the efficiency of the heat exchange pipes 7 substantially unaltered.

The inlet pipe 8 is connected to the cold water supply (not shown). The inlet pipe 8 is shown in Fig. 1 as exposed, but it may be hidden in the construction of the shower, if so desired. The inlet pipe 8 may supply cold water direct to the heat 250784 exchange pipes 7, or the water coining in through the inlet pipe 8 may also have received some portion of pre-heating (for example in a solar heating unit).

The outlet pipe 9 may be connected to the inlet to a hot water cylinder (not shown), or to any other heating device, for further heating of the water. Alternatively, if so desired, the outlet pipe 9 may supply the inlet water for mixing with hot water for the showerhead of the shower in use. As with the inlet pipe 8, the outlet pipe 9 may be exposed, as shown in Fig. 1 or constructed to be hidden from the user, as is desired.

In practice it has been found that for an 8.5 litres/minute flow rate through the pipes 7, with a cold water supply temperature of 16° C and a shower head temperature of 44.5° C, 5700 watts could be recovered, with the cold water being passed once through the pipes 7 before passing to the hot water cylinder or other heating device.

The heat exchange pipes 7 have been described above as being formed integrally with a shower base 2. However it will be appreciated that a set of heat exchange pipes 7 may be manufactured and installed within an existing shower base, with appropriate modification, by known means, to the structure of the base of the shower to accommodate the inlet and outlet pipes (8, 9) and any raising of the drain 4 to include a weir as described above.

Alternatively the pipes 7 may be formed separately from the base 2 (in a similar manner to that described above). The pipes 7 may then be welded into a base 2. Alternatively, the pipes 7 may be chocked in position by wedges (not shown) to support the pipes slightly above the base 2 of the shower. Alternatively, if so desired,

Claims

250784 the underside of the pipes 7 may be appropriately shaped that the pipes 7 can be rested on the base 2 of the shower. Thus the weight of the pies 7 and the rigid connections to the inlet and outlet pies (8, 9) would keep the pipes 7 from moving. The above invention has been described with reference to a shower for use in a domestic setting. However it will be appreciated that showers used in other settings (for example sports complexes) may also be appropriately adapted or constructed. Also, the above invention may be adapted to be used in showers where bodies or carcases, not human, are being washed in hot water. 250784 WHAT I CLAIM IS.-

1. A heat recovery system for domestic or commercial showers, said system including: a heat exchanger with at least one heat exchanging pipe therein with an inlet pipe and an outlet pipe, said heat exchanger being dimensioned to be capable of being fitted into a base of a shower; and outlet means for waste water; wherein said inlet pipe is connectable to a source of cold water, and said heat exchanging pipes are positioned across a substantial portion of the surface of the base of said shower.

2. A heat recovery system for domestic or commercial showers as claimed in Gaim 1 wherein said heat exchanger includes a plurality of pipes through which said cold water passes in series.

3. A heat recovery system for domestic or commercial showers as claimed in Claim 1 wherein said heat exchanger includes a plurality of pipes through which said cold water passes in parallel.

4. A heat recovery system for domestic or commercial showers as claimed in any one of claims 1 to 3 wherein the or each pipe is formed in two parts with a separating strip therebetween, such that the cold water flows through the or each pipe in a double flow.

5. A heat recovery system for domestic or commercial showers as claimed in 8 250784 claim 4 when dependent on either of claims 2 or 3 wherein said separating strips are formed integrally as one sheet.

6. A heat recovery system for domestic or commercial showers as claimed in any one of claims 1 to 5 wherein the cross-section profile of the or each pipe is circular with a flat portion at the top and the bottom of the or each pipe.

7. A heat recovery system for domestic or commercial showers as claimed in any one of claims 1 to 6 wherein said waste water outlet means is elevated, to form a weir, the sides of said outlet being slotted.

8. A heat recovery system for domestic or commercial showers as claimed in any one of claims 1 to 7 wherein said inlet pipe is connected to a source of cold water.

9. A heat recoveiy system for domestic or commercial showers as claimed in any one of claims 1 to 7 wherein said inlet pipe is connected to a source of pre-heated water.

10. A heat recoveiy system for domestic or commercial showers as claimed in any one of claims 1 to 9 wherein said outlet pipe is connected to further beating means.

11. A heat recoveiy system for domestic or commercial showers as claimed in any one of claims 1 to 9 wherein said outlet pipe is connected to an inlet cold water pipe 250784 for said shower.

12. A heat recoveiy system for domestic or commercial showers as claimed in any one of claims 1 to 11 wherein said heater exchanger and shower base are formed integrally.

13. A heat recovery system for domestic or commercial showers as claimed in any one of claims 1 to 11 wherein said heater exchanger is fitted to an existing shower base.

14. A heat recovery system for domestic or commercial showers substantially as hereinbefore described and with reference to the drawings accompanying the provisional specification. DONALD MURRAY CLUCAS. by his authorised agents, P.L. BERRY & ASSOCIATES. 10