AU622169B2 - Improvements in or relating to solar water heaters - Google Patents

Description

-1- P/00/01 1 Regulation 3.2

AUSTRALIA

Patents Act 1 990 6 2

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT 000 o 04 004.0 0 0 0 0 00 0 0 0 Invention Title: Improvements in or Relating to LJoiar Water Heaters 0 0 04,444 0 O0 00*0 0 0

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9000* 0 0 4,00 00 The following statement is a full description of this invention, including the best method of performing it known to me/us: GH&CO REF: 20361-A/CLC:BC 00 "9 ,o o to.

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-2- This invention relates to solar water heaters.

There are a number of problems associated with the known solar heaters. One of the major problem is a satisfactory, simple and cheap arrangement which will enable a solar heater to deliver heat to a level lower than the collector without using any outside energy source.

I believe I have developed a solar water heater which will overcome some of the difficulties encountered in both of these areas or which will at least provide a useful choice over known solar water heaters.

Accordingly in one aspect the present invention consists in a sealed thermal pump system capable of moving a liquid contained within the sealed system and including regions not filled with liquid, said system comprising: a heat receiving means selected from a solar collector or a heat exchanger and having a liquid inlet thereto and a liquid outlet therefrom; a liquid vapour/liquid separating chamber above said heat receiving means having a liquid tight conduit from the outlet of said heat receiving means to its own inlet, said chamber including an outlet for condensed liquid from a collection zone therefor and additionally having a liquid vapour outlet; heat exchange means below said heat receiving means and said liquid vapour/liquid separating chamber to receive condensed liquid from the outlet for condensed liquid of the liquid vapour/liquid separating camber, said heat exchange means being arranged to extract heat from the condensed liquid, said heat exchange means having an inlet and outlet, and having its inlet for the condensed liquid connected by fluid tight conduit from said condensed liquid outlet of the chamber;

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4ror 0000 000004 0 -3a liquid level controlling chamber positioned below said liquid vapour/liquid separating chamber but having an inlet thereto and fluid tight conduiting from the vapour outlet of the liquid vapour/liquid separating chamber, said liquid level controlling chamber including an inlet thereto for said liquid from said heat exchange means, said inlet being connected by fluid tight conduiting from the outlet of said heat exchange means, and further having an outlet therefrom conduited by liquid tight conduiting to the inlet of said heat receiving means, said liquid inlets and liquid outlet of said liquid level controlling chamber being substantially above said heat receiving means, the liquid inlet of the liquid level controlling chamber being above the liquid outlet therefrom, the arrangement being such that in use liquid vapour moves from said heat receiving means into the liquid vapour/liquid separating chamber, condenses at least to some extent and liquid passes down through the heat exchange means and back up through the liquid f'l level controlling chamber while the remaining liquid vapour passes directly to the liquid level controlling chamber from the separating chamber, wherein liquid vapour loss from the separating chamber is compensated for by a flow of liquid from the liquid level controlling chamber back into the heat receiving means.

Preferably said liquid is water.

Preferably said heat receiving means is a solar collector.

Preferably any of the features of the system are substantially as hereinafter described with reference to any of the accompanying drawings.

In a further aspect the invention consists in a solar energy collection system incorporating features which provide a sealed thermal pump system in S accordance with the present invention.

Preferably said thermal pump is substantially as hereinafter described with reference to any of the accompanying drawings.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

F1 One preferred form of the invention will now be described with reference to the accompanying drawings in which: N T Om n

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4 A L -4- Figure 1 is a schematic sectional view through a collector according to the present invention; Figure 2 is a section through an alternate form of collector according to the present invention; Figure 3 is a diagrammatic side view through a collector according to the present invention; Figure 4 is a diagrammatic view of the thermal pump according to the present invention; Figure 5 is a diagrammatic view of an alternate form of pump as illustrated in figure 4; Figure 6 is a diagrammatic view of a circuit in accordance with the present invention having a thermo-syphon circuit from a solar plate, eg, Freon (F11) working fluid, which is connected through heat exchange means (eg a boiler) into a heat pump circuit in accordance with the present invention, that circuit being shown diagramatically in part only; Figure 7 is a diagrammatic view of a portion of a pump in accordance with the present invention showing the preferred form of condensor for steam from either directly the solar plate (in single stage system) or from a heat exchanger (in a two stage system), the arrangement being such that multiple entries of steam pass into a zone of the apparatus where condensation thereof allows the collection and feeding of hot water and such that that portion of the steam that does not immediately condense passes into a different zone where preferably surface enhancing means is included and through which a cool liquid is circulated; Figure 7A is a similar view to that of figure 7 but showing how if desired in addition a reservoir tube for the cold water can be disposed below the lower most portion of the apparatus of figure 7 to allow the necessary feed of cold liquid into the packed lower tube or reservoir; 00 o 0o+ o o a 0 0 00 0 0 4 410 40 4 0 140 00t Figure 8 is a diagrammatic cross sectional view of the apparatus shown in figure A, the dotted upper circle showing the upper side extremities of the steam condensation upper tube, with the immediate next shown circle being the lower most zone of the upper tube from which the hot water feed is taken; Figure 9 is a diagrammatic side elevation view of the apparatus shown in figure 7A substantially at X-X, it being seen how any lagging around the system can have air passageways disposed therethrough to provide a cooling effect on the tubing, such cooling air ducts preferably being welded to the lower most portion of the reservoir; Figure 10 shows an overall system employing a variation of the present invention but using apparatus substantially as depicted in figure 8; Figure 11 is a view similar to figure 7A of the pump but in a form which it is believed improves efficiency and which has a greater ease of set up as far as filling with water or fluid is concerned while expelling air; Figure 12A is a view in the form of say figure 10 showing in broken outline parts of the end view of the pump as shown in figure 11 so as to better understand the relationship of those portions of the pump shown in solid outline and the heat exchange circuit; and Figure 12B is a similar view to that of Figure 12A but showing different parts in solid outline for ease of explanation.

In a preferred form of the invention a collector 1 is made up of a sheet of copper 2 in which have been formed at regular spacings V grooves 3. These grooves may for example have a side dimension of 15 mm and a base dimension of 30 mm but it will be appreciated that the dimensions are not critical.

The angles are important and it is desirable to retain the triangular configuration with the apex angle 900 and the angle with the main sheet 450. The spacing between the grooves 3 again is not critical but I have found that a particularly suitable and convenient spacing is 95 mm. The grove 3 has located therein a means for conveying fluid, for example, water.

The embodiment illustrated in figure 1 shows the conduit 4, for example, a copper conduit which is welded or soldered at 5 into the V recess.

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99~W0 9 4 In figure 2 the collector la has the similar copper sheet 2a with the similar recesses 3a formed therein but in place of the conduit 4 a plate 6 is welded or otherwise suitably fixed on the undersurface of the sheet 2a to complete the chamber 7 formed in association with the groove 3a. The plate 6 can be copper or any other compatible material such as stainless steel.

The collector 1 or la has a top manifold 8 and a lower or inlet manifold 9.

The inlet manifold is on the under surface of the collector, that is with the periphery of the manifold in the plane of the collector and be directed from that point downwardly whereas the upper manifold 8 is oppositely located as is apparent from the drawings. The manifold 9 is an inlet attachment 10 in the end thereof and the manifold 8 has an outlet 11 at the highest point of the manifold. If the manifold was inclined slightly on an angle the outlet 11 would be at the top side of the angular inclination. If on the other hand the outlet was in the centre aT is the instance in my preferred construction then the manifold would be inclined from each end toward the centre so that the outlet 11 is at the highest point.

The particular construction as described above using the collector is given by way of example, but the aspect of the surface treatment for the collector can be applied to any particular construction of collector. The collector however manufactured and in whatever form is subjected to a surface treatment. The exposed surface of the collector is cleaned to remove any dirt and oxides leaving effectively the virgin copper. Normally I would expect to use copper sheet but it would be feasible to use another material where copper had been plated in a reasonably thick layer onto the base metal.

In any event whatever material or form is selected the virgin surface of copper once prepared is then exposed to an atmosphere of hydrogen sulphide.

This is achieved by placing the member to be treated in a chamber preferably at an elevated temperature of 140 0 C. All oxygen is expelled from the chamber using an inert gas such as nitrogen and hydrogr- sulphide gas introduced in the chamber. This gas should be essentially free of any impurities and can be formed by passing hydrogen through molten sulphur and using a nickel catalyst. This technique is known and produces a pure hydrogen sulphide gas which can then be directed to the treatment chamber.

The time of treatment is sufficient to ensure a relatively even coating of copper sulphide crystals as formed on the metal sheet. Copper sulphide crystals leave a matt grey coating on the copper.

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i *0 ro a o o a 0 a 0 09 09r 9 d 0 -7- The invention may be given effect by cleaning chemically and subjecting the plate to the treatment above described. I believe advantages can be gained if the cleaning is mechanically achieved using a wire buff. This causes minor surface irregularities in the copper and these irregularities leave the virgin metal to react producing what is essentially a roughened surface but still with only the very thin coating of the copper sulphide generated as a consequence of exposure to the atmosphere of hydrogen sulphide.

A collector as described herein has been demonstrated by me to be a particularly efficient collector.

The thermal pump of the present invention is illustrated in figures 4 and The collector 12 can be of the type previously described and preferably would be but it could also be any other form of solar collector. The thermal pump is made up of a condensation chamber 13. This chamber is any convenient size and shape. The chamber must be located above the collector and to achieve satisfactory results ought not to be too small. Apart from the practical consideration of space and cost size is not significant. The condensing chamber should be formed from a material having a relatively poor conductivity. I have found that this can be achieved in a practical sense by using stainless steel. However, the material selected must be able to withstand a lower than atmospheric pressure and the type of temperatures which might be experienced in use.

Extending down from the condensation chamber is a two circuit thermal column. In the diagrammatic-form of the invention illustrated in figure 4 the condensation chamber 13.is shown to blend with the column but is desirable for the change in material from heat conductive to non-heat conductive to occur at a level indicated by arrow 15 although this is not critical and it could be anywhere around level 15 to a height just below the water level 16 indicated by a dotted line in the drawings. The two circuit column is built up having the outer tube 17 and an inner tube 18. The upper end of the outer tube is connected to an extension conduit 19 which rises above the water level 16 and has a collector 20 which takes water form the baffle pll'. 21 so that any water vapour condensed in the condensing chamber is directed by a baffle 21 through the collector 20 into the conduit 19 and thence down so that the water can be recirculated to pass through conduit 22 into the collector 12.

aooo 000 a 0 4 0 9 0 0 0 4a 0 0 4, 0 -8- The condensor might have improved characteristics if a number of sections of condensating rings or balls 23 are located in the chamber. It is not thought that this would be critical but if it was included the balls would be held between suitable mesh dividers as illustrated in the drawings.

A hot water conduit 25 extends from the collector 12 and has the outlet 26 above the water level 16. A by-pass or short circuit conduit 27 is also preferably provided between the conduit 25 and a point at the column 14 are just above the inlet for the conduit 22. This conduit 27 is a small diameter conduit, eg, up to about 5 mm. The actual size will to some extent depend upon the collector and the function is to provide a short circuit path as will be apparent from the following description.

I The column 14 terminates in a heat exchanger 28. The heat exchanger is diagrammatically illustrated and can be of any convenient design so that the U heat which is passed down by the thermal pump can be transferred to be used Sat an appropriate location. The chamber 13 has a partial vacuum. The -I efficiency is improved if this vacuum is high and the object is to ensure that the boiling temperature of the fluid in the collector is reduced. It is d, ,irable to ensure that in the condensing chamber there is some presence of 11 amount of an inert gas. This has the effect of slightly increasing the boiling temperature, for example, if water is used in the collector, but primarily operates as a cushioning effect in the event of there being a complete and rapid condensation of any water vapour in the condensor.

The thermal pump as described in figure 4 is modified in figure 5. The collector 12 is the same. The hot water conduit 29 and the low water conduit 30 are connected with the condensor 13a and the column 14a. In this instance the water level of 16a is indicated and the communicating conduit V 27a serves essentially the same function as previously. That is, to allow water to return to the column 14a when the pressure build up in the collector 12 is insufficient to drive water from the collector 12 up through pipe 29 and out the outlet 26a.

This by-pass conduit allows for a smoother operation of both units.

In the case of the pump illustrated in figure 5 the cold water rises through the inner column where as the inner pipe 18 in the version shown in figure 4 0 1 ROA has the hot water passing down through this member. To some extent the kc~LJJ T I .jj~j

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selection of the form will depend upon the nature of the heat exchanger 28a and other criteria. More normally the form of invention illustrated in figure 4 would be used to ensure that the hot water was located at the botom in the heat exchanger. However, there could be instances where the construction indicated in figure 5 has a preference. Modifications to the above described invention can be made. These could include a twin pipe system instead of a pipe within a pipe so that there is a hot water down pipe and a cold water up pipe. This wil tend to reduce the heat exchange between the hot and the cold water and adjustments might be reqired in the by-pass pipe either increasing this pipe in size slightly or increasing the size substantially and introducing a thermostatic valve control. Additional valves may also be included so that a user can relatively easily control the level of water in the assembly and also pull a vacuum in the chamber above normal water level.

The configuration for the heat exchanger could also be modified using a flat heat exchanger, for example, encompassing a substantially shaped configuration of pipe. This can be located in the confined space likely to be encountered under the floor of a dwelling.

With respect to the collector the lense used therein may be a polycarbonate sheet having an angular corrugated surface with the faces of the corrugation approximately 50 millimetres in length. The improved efficiency as a consequence of such a collector lense will be apparent to an expert in the field.

The arrangement as shown in figures 6 and 7 can be understood by reference to the explanatioi in relation to figures 7A, 8 and 9 since those figures relate to a variation thereof. As far as figure 6 is concerned it is envisaged that the solar plate 30 with its Freon or other working fluid to the level indicated by the lower most dotted line would pass through a heat receiving means (eg, heat exchanger 31) to hereby provide a circuit in accorance with the present invention. The columns in accordance with the present invention would provide a cold water feed through inlet 32 and a hot water feed out of the condensing portion of the circuit. Cold water together with some condensed water from the packed zone 34 would pass down via conduit 35 through, if desired, optional water reservoir 36 to the heat exchanger 31. The packed zone 34 would be packed with a suitable material, conveniently glass balls or rings, to maximise the surface area available for the water vapour to condense on. Any steam generated in the boiler ('j7~

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would pass upwardly through conduits 37 into the zone 38. The arrangement as depicted in figure 6 can be performed with the apparatus as shown in figure 7 where corresponding reference numerals are used in figure 7. The reference numerals in figure 7 are followed by the letter A similar notation is used in conjunction with figure 7A but in this instance the references are followed by the letter A. Similarly with figure 8 which is the diagrammatic side elevation view of the arrangements shown in figure 7A.

Figure 9 shows how an air tube or tube 39 can be provided through the desired lagging so that the necessary cooling of the lower zone 34A occurs.

In use therefore depending on whatever form of the present invention is employed it can be seen that steam generated passes up the conduit 37 and is selectively condensed in zone 38, 38A or 38B so that the same can be let out through the corresponding hot water outlet 33A or 33B. Any steam not immediately condensed wiil join with the cold water flow in t:-rough the packed zone 34 where inlet 32, 32A and 32B respectively and down out of outlet 35, 35A and 38 respectively via a reservoir 36 or 36A as appropriate.

The liquid levels are substantially as shown in figure 6 and 8 by the dotted lines with the lower line being that of the working fluid in the solar energy system and with the upper level being that of the water level within the pumping system of the present invention.

A similar arrangement to that which has been described (especially with relation to figure 8) is shown in figure 10 where it can be seen that the hot water downward flow passes through selective heat exchangers and back up into the zone 34 via entrance 32. It can be seen how a series of hot water cylinders for industrial ordomestic use with optional electric enhancement on the hotter of the two. Cylinders can be interlinked with the heat exchanger. Persons skilled in the art will appreciate such a system.

The most preferred form of the pump component is as shown in figure 11. It can be as shown in solid outline or can be increased in size to a form as shown which embodies the broken outline disposed to the right. As described earlier in the reference to the drawings, figures 12A and 128 show an end view of the arrangement from the left hand end.

In figures 11, 12A and 128 there is shown a water conduit 39 which passes down through the heat exchanger 40 and brings the cooled water back by i conduit 41 into the port 41A shown in figure 11, the cooled water entering

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~NT t 4 -11the chamber 42. Up above chamber 42 is chamber 43 which is in communication with chamber 42. It includes the outlets 39, ie, the water conduit 39 previously referred to. The chamber 43 also includes inlets 44 from the solar plate, the conduit shown in figure 12A connected to inlet 44 being designated as 44A.

Disposed below chamber 42 but in communication therewith by a conduit 45 is a liquid collection chamber 46 having a water outlet 47 which feeds water to the solar plate to be heated and which returns from the solar plate via the conduit 44A previously referred to.

A feature of the pumping and system arrangement as depicted in figures 11, 12A and 12B is the provision of an outlet 48 from an upper extension of chamber 42 (at a high point in the system) which is in communication via its outlet 45 with the lower chamber 46 but additionally by the additional conduit 49. This allows for an easier setting up of the system while excluding air. It is possible to overfill the system using, for example, a sealable inlet port 50 so that all of the pump system as depicted in figure 11 is filled absolutely with water (bleeding taking place if necessary elsewhere in the circuit) such that there is an overflow of water from outlet 48. At that time it is possible to seal outlet 48 and to allow the water to fall back and draw the appropriate vacuum within the system after which port 50 would be sealed. A person skilled in the art will appreciate how this can be achieved.

It is believed therefore that the heat pumping system of the present invention should find wide spread acceptance.

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Claims (3)

1. 2. A system as claimed in claim 1 wherein said liquid is water.
2. 3. A system as claimed in claim 1 or claim 2 wherein said heat receiving means is a solar collector.
3. 4. A sealed thermal pump system substantially as hereinbefore described with reference to any one embodiment shown in the accompanying drawings. Dated this 6th day of November 1991. HBNRY GRUNWALD By their Patent Attorneys GRIFFITH HACK CO. i ii I i L