GB2448384A

GB2448384A - Regenerative heating system

Info

Publication number: GB2448384A
Application number: GB0721635A
Authority: GB
Inventors: Edward John Guy
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-11-03
Filing date: 2007-11-03
Publication date: 2008-10-15
Anticipated expiration: 2027-11-03
Also published as: GB2448384C; WO2009056816A1; GB0721635D0; WO2009056816A9; GB2448384C2; GB2448384B

Abstract

A central heating system in which gravity and thermal effects are used to create a pressure difference to drive a heated fluid around a circuit. The circuit comprises a boiler 1, an optional circulation pump 6, rising feed and return pipes 2b and 4b, and a counterflow heat exchanger formed from a downward flow feed channel 2a and an upward flow return channel 4a. Preferably, the heat exchanger is of a coaxial construction. The lower end of the heat exchanger is connected to a heat dispenser 3, which may be a radiator. A number of different forms of panel or partitioned tube radiators are also described which may be used to improve the flow characteristics in the system and incorporate similar induced flow by means of a downward flow feed channel (35, fig. 12) and an upward flow return channel (36, fig.12). In another embodiment, a circuit comprising a water storage tank (13, fig.20) for supplying taps with hot water may utilise a similar regenerative circulation to make pre-heated water available at a closed tap (106, fig.20). Preferably, the system incorporates solar collectors (132, fig.32) and photovoltaic panels (133, fig.32).

Description

REGENERATIVE HEATING SYSTEM

This invention relates to a heating system for a building in which heat transfer fluid, generalLy water, is heated by a boiler and suppLied to radiators, domestic hot water storage vessels and other heat dispensing devices through pipe circuits which return fluid, not only to the boiler but aLso to a storage vessel, for recycling.

Modern heating circuits generally comprise at Least one pump, usually electrically driven, to provide forced circuLation of fluid through the pipes. The need to provide such a pump increases the cost of the installation and increases the power -consumption, also the pump requires periodic maintenance and is a common cause of breakdown of the system.

Prior to the introduction of pump driven systems it was possibLe to provide a circuit for a heating system in which fluid was passed around the circuit under the effect of temperature alone. As hot fluid has a lower density than cold fluid, when the circuit feed and return pipes extend upwardly from the boiler the heated fluid will tend to rise in the feed pipe and create a pressure difference to drive the fluid around the circuit. However, thermo-syphon (unforced) systems of this nature can only work if the radiators are at a much higher vertical level than the boiler. If the radiators are at or near the same level as the boiler, or beLow it, cooling of the fluid by the radiators causes a pressure difference between the inlet and outlet pipes extending above the radiator which opposes and cancels the pressure difference generated by the boiler.

The low circulation pressure generated in older thermo-syphon systems necessitated the use of large buLky pipes and radiators to circulate large volumes of water around the system making it unsuitable for smalLer family homes and restricting its use to larger and taLler buildings.

In modern buildings which have no basement it is often inconvenient or expensive to provide a large difference in height between the boiler and the radiators which it supplies. The present invention is intended to provide a heating system of variable output, using regenerative heating principLes instead of a pump to provide circulation, while using similar size pipes and radiators as used in present pump driven systems, and in which the radiators or other heat dispensing-devices may be at the same LeveL as, or even below, the boiler. The present invention is also intended to provide hot water for immediate use at a tap by using the regenerative principLes as described herein.

According to the invention there is provided;-a heating system comprising a boiLer for heating a liquid, a feed pipe conducting heated liquid from the boiler to at least one heat dispenser and a return pipe returning cooled liquid to the boiler for recycling, the feed and return pipes extending upwardly from the boiler and downwardly towards the heat dispenser, heat exchange means arranged to transfer heat from the liquid in the downwardly extending part of the feed pipe to the liquid in the downwardly extending part of the return pipe to at Least partially equalise the Liquid temperatures therein, wherein substantially horizontal feed and return mains extend between the upwardly extending pipes from the boiler and to the heat dispenser or other heat exchange means.

The heat dispenser or other heat exchange means may be positioned below or level with the boiler and may comprise a radiator, a coil for indirect heating of water in a tank or other device intended to discharge heat. A heat sink such as a radiator or coil for indirect heating of water may be provided for withdrawing heat from the return pipe at a point between the downwardly extending part of the boiler.

Comfortable, non-fluctuating, room temperatures can be achieved in single story buildings with regenerative pnnciples of circulation, as described herein, while using the same conventionaL low water content panel type radiators connected to extended horizontal pipe runs as used in pump driven systems, with mains heights of below 4m.

For older thermo-syphon type systems horizontal mains usuaLLy provided a neutral gravity effect at any height whereas incorporation of regenerative effects in co-axiaL horizontal mains provides a beneficial circulatory effect at any height.

The regenerative principles and methods used to effect heat exchange between supply and return pipes in order to enhance the gravity effect in heating systems can also be used to beneficial effect in domestic hot water heating circuits. In present instalLations which supply heated water for domestic needs it is usually necessary to draw considerable amounts of coLd water from the pipe-run between the tap and the storage tank before receiving heated water from the tank.

According to the invention there is provided a means to make heated water immediately available at a tap when opened. The system comprises a circuit, which, with taps closed, is a closed-Loop circuit to enable pre-heated water to circulate around the system, but once a tap is opened to atmosphere it converts to an open-circuit allowing pre-heated water to flow immediately from the open tap.

The water being discharged from the tap uses pipe channels previously used to circulate pre-heated water between the storage tank and the tap position.

The regenerative heating system described herein can be driven by any source of energy, whether it be of a fossil or non-fossil type fuel, including solar. Boilers of simple design, Like wood burning appliances, with thermostatic controls will be preferable for use with the regenerative system described herein in preference to the more complicated pump driven boiLers, but they may also be used if desired.

Solar heat collectors and solar photovoltaic paneLs may be used in known manner to provide heat to domestic water systems and to provide a source of etectncity for domestic use. A combination of coLlector and photovoltaic panels may be used as described herein to drive regenerative circuits for supplying heat and electricity for instant use in buildings or for the purpose of storing heat during summer months for use during winter months. The ability of a regenerative system to circuLate heated water to a heat emitter below the boiler and to re-circulate it to mains above the boiler for return down to the boiler, even without a pump, makes it suitable for use with solar coLLectors and photovoltaic panels.

Heating systems according to the embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:-Fig. 1 shows schematically a heating system for a single story building, according to the invention, Figs. 2, 4 and 6 show schematically heat exchanger's for use in the system of Fig 1, Fig. 3, Fig. 5 and Figs 7 and 8 show cross-sections of the exchanger's of Figs. 2, 4 and 6 respectively, Fig. 9 shows a heating system in a two story house according to the invention, Fig. 10 shows another heating system according to the invention, Fig. 11 shows part of the system of Fig. 10, Fig. 12 is a part perspective view of a panel radiator for the system of the invention, Fig. 13 is a partial horizontal cross-section of the top of the radiator of Fig. 12, Fig 14 is a partial cut away perspective view of another and tubular radiator for the system of the invention, Fig. 15 is a partial horizontal cross-section of the top of the radiator of Fig. 14, Fig. 16 is a partial perspective view of another panel radiator for the system of the invention, Fig. 17 is a partial perspective view of a square tubular radiator for the system of the invention, Fig.18 is a partial perspective view of another tubular radiator for the system of the invention, Fig. 19 shows another heating system according to the invention, Fig. 20 shows a system in which contra-flow circulation within separate adjacent channels or co-axiaL pipes is used to supply pre heated water from a storage tank to a cLosed tap for immediate use, according to the invention, Fig 20a shows an extension to the system in Fig 20 to make pe-heated water available to a muLtiple number of closed taps, according to the invention.

Figs. 21 and 21a shows the system at Figs.20 and 20a when supplying a flow of pre-heated water to one or more open taps, according to the invention, Fig. 22 shows another system similar to Fig. 20 with check valves embodied for making pre-heated water avaiLable at a closed tap, according to the invention, Fig. 22a shows an extension to the system in Fig.22 to make pre-heated water availabLe to a muLtiple number of closed taps, according to the invention.

Fig. 23 shows the system at Figs. 22 and 22a when suppLying a fLow of pre-heated water to one or more open taps, according to the invention, Fig. 24 shows another system for making pre-heated water available to more than one cLosed tap via a manifoLd device, according to the invention, Fig.24a shows a cross section through the manifold device for the system in Fig 24, according to the invention.

Fig. 25 shows the system at Figs 24 and 24a when supplying a flow of pre-heated water to more than one open tap, according to the invention.

Fig. 26 shows another system similar to Figs. 24 and 24a wherein it embodies check valves for making pre-heated water available at more than one closed tap, according to the invention.

Fig. 27 shows the system at Fig. 26 when providing a flow of pre-heated water to more than one open tap, according to the invention.

Figs. 28, 29 and 30 show, by way of example, check valves using a ball and seat method to control circulation and flow of pre-heated water through the systems, according to the invention.

Fig. 28 shows the positions of baLL valves 112 and 113 and the direction of circulation of the pre-heated water when tap 106 is cLosed, according to the invention.

Fig. 29 shows the positions of ball valves 112 and 113 and the direction of flow of the pre-heated water when tap 106 is open, according to the invention.

Fig. 30 shows an enlarged view of a baLl vaLve in the open position on its seat allowing circulation, or flow, of pre-heated water around the ball.

Fig. 31 shows a water storage tank I 3a with multipLe connections for several water feed lines and several supply and return pipes for the provision of separate circuits, for the systems of the invention. This arrangement provides a choice of circuit arrangements which may be more suitable for larger type buildings than are those shown in Figs. 20 to 27.

Figs. 32, 33, 34 and 35 show a system which uses solar energy to drive a regenerative circuit for the purpose of providing heat to a building either for instant use or for storing heat during summer for Later use in winter.

Figs 36 and 37 show alternative methods for negotiating a bend or for making connections between honzontaL and vertical pipes, Fig. 38 shows more than one tap installed in a annuLus supply Line similar to those shown in Figs. 20 to 27 and 34.

Referring to Fig.1, it shows a heating circuit in a single story buiLding comprising a boiler for heating water which is fed from the boiler to feed pipe 2 to a radiator in another room of the building. The water is returned from the radiator 3 to the boiler through return pipe 4. The boiler may be of simple conventional type and the circuit may be provided with an expansion tank and device for replenishing the water in the system in known manner. The feed and return pipes extend upwardly above the boiler and downwardly towards the radiator, which in the embodiment shown is substantially at the same Level as the boiLer.

The downwardLy extending parts 2a and 4a of the feed and return pipes are arranged as a heat exchanger so that heat is transferred from the water in pipe part 2a to the water in return pipe part 4a before the water fed through pipe 2 reaches the radiator. The effect of this heat transfer is to remove or substantially reduce the difference in temperature between the pipe parts 2a and 4a. The difference in water density between these pipe parts, which wouLd otherwise oppose circulation of water through the pipes in the desired direction, is accordingly removed or reduced.

Return pipe 4 as shown also has connections to a radiator 5 in conventional manner in the downwardly extending part of pipe 4b. This radiator may be positioned in another room of the building and gives a reduction in the temperature of water returning to the boiler. As the hotter water in part 2b has a less density than the cooler water returning through part 4b, and the difference in water density between 2a and 4a is small, the water is driven in circulation through the circuit under the effect of gravity alone and no pump is required. The higher the heat output of the boiler, the higher the water temperature in the feed pipe so that the rate of circulation of the water is greater at a higher boiler output.

Where the temperature difference between the flow and return line 2a and 4a at the top of the heat exchanger is adequate and/or where the transfer of heat energy between flow and return lines in the heat exchanger is sufficient to cause an increase in kinetic energy in the liquid, the thermal effect may be adequate to sustain circulation without the need for radiator 5 to be connected or operative.

A muLtiple return drop such as several pipes 4b may provide some assistance to the circulation of water within the system up to a limited extent.

Although not a necessity, a pump or other circulating device, can be inserted into the system in known manner, if desired.

Figs. 2, 4 and 6 show different types of heat exchange arrangement between parts Za and 4a of the pipes. In the arrangement of Figs.2 and 3 the pipe parts 2a and 4a are arranged parallel and both are surrounded by a water-filled jacket 6 so that heat is transferred from part 2a to part 4a through the water in the jacket. The jacket may be supplied with water from an external source, or supplied through orifices 8 (see below). In this arrangement pipe parts 2a and 4a may have the same diameter as the remainder of pipes in the circuit, and resistance to flow of the water through the pipes is not restricted in any way. The heat exchanger may be constructed entirely of standard pipes and fittings and the external water jacket, surrounding pipe parts 2a and 4a compLetely, gives good heat transfer characteristics. This type of heat exchanger may be used with advantage in factories and offices where bulk is not a problem and in which the pipes of the heating circuit are commonly in enclosed ducts.

Figs. 4 and 5 show an alternative type of heat exchanger in which part 4a is surrounded by a coaxiaL part 2a. This arrangement is less bulky than that of Fig. 2, a high wetted area of heat exchange is stilL obtained and standard pipe components may again be used. In this arrangement however the resistance to flow though the exchanger may be higher.

In the arrangement of Fig. 6 and Fig. 7 or 8 the parts 2a and 4a together form a single pipe. In the Fig 7 arrangement the singLe pipe is divided by partition 7 through which heat is conducted, partition 7 dividing the pipe into pipe parts 2a and 4a. The cross section of the single pipe shown is circuLar but may be square.

This arrangement is economicaL in material and low in bulk but the area through which heat is transmitted between parts 4a and 2a is Limited. The arrangement of Fig. 8 is similar but pipe part 2a comprises a pipe of lessor diameter within pipe part 4a. The Fig.8 arrangement has a greater area available for heat transfer than the Fig. 7 arrangement. The heat exchanger's shown in Figs. 2, 4 and 6 can be constructed from tubing other than having a round cross section. For instance a square cross section can be used.

In all these types of heat exchanger the materials used for components through which heat passes should be good heat conductors and it is preferable for the outer surfaces of the heat exchanger to be insulating. This may be achieved by making all internal components of copper, generaLly copper standard pipe, and by lagging the external surfaces. Alternatively, insuLating materiaLs may be used for the external surfaces.

For any type of wet heating system, it is generally necessary to provide a priming facility to allow circulation of water in the desired direction unrestricted by air locks. This may be achieved by forming an orifice of restricted diameter, marked 8 in Fig. 1, between parts 2a and 4a at the upper end of the heat exchanger to aLlow any air in the internal pipe to enter the externaL pipe which can be vented to atmosphere in known manner. Once flow has started, the cycle of water through the system is self-sustaining while the boiler continues to heat the water.

In the arrangements shown in Figs. 2, 4, and 6 the radiator is connected in series with the pipes 2 and 4. Alternatively, the radiator may be connected in parallel with the pipes by suitable modification either within the radiator itself or at the lower part of the heat exchanger formed by parts 2a and 4a.

Fig.9 shows diagrammatically a possible arrangement using the heating arrangement of the invention instaLled in a house. A boiler I situated on the first floor, or ground floor of a house having a basement, supplies hot water to a radiator 10 on the floor below, a radiator 11 on the same floor, a radiator 12 on an upper fLoor and the coil of a hot water supply tank 13. The water is impelled around the piping circuit by the temperature difference in the feed and return pipes leading upwardly from the boiler and the pipes extending downwardly down to radiators 10 and 11 are provided with heat exchanger's as described above to cancel the pressure differences opposing the circulation of water. Radiator 12 and tank 13 act as heat sinks on the return pipe. In the arrangement shown the radiators are at floor level but they may alternatively be positioned at ceiling Level, the heat being radiated downwardLy.

Fig. 10 shows another arrangement in which a number of radiators are fed with water by means of a ring main. The boiler 1 supplies hot water through upwardly extending pipe 21 to a horizontal ring main 22 which, as shown in Fig. 11, comprises pipes separated by internal heat conducting partition 23 so that the water temperatures in the feed and return pipes tend to equalise. The horizontal main may be installed below a floor of a building to be heated, or behind the skirting at floor level. Radiators 27 at substantialLy the same level as the horizontal main, may be of the parallel type in which water is withdrawn from and returned to a continuous pipe and radiator 24, below the Level of the horizontal main, is of the series type taking water from the horizontal feed pipe of the ring main and returning it to the horizontal return pipe.

Downwardly extending pipes 25 connected to radiator 24 are also joined by a internal heat-conducting partition 23.

In this arrangement pipe 21 from the boiler supplies hot water to the horizontal feed pipe of the ring main and pipe 26 withdraws water from the return pipe of the main to deliver it to the coil of hot water tank 28 acting as a heat sink. Cold water is returned to the boiler by pipe 29 and the water is impelled around the circuit by the temperature difference between pipes 21 and 26 containing hot water and pipe 29 containing colder water. In this arrangement heat exchange takes pLace not only in pipe 25 but also in the horizontal pipes 22.

The horizontaL ring main may be at, above or below the LeveL of the boiler and more than one ring main may be instaUed to heat more than one floor. It is possible to use this system to provide under floor heating.

The principle and methods used to effect the heat exchange between supply and return pipes in order to enhance the gravity effect in heating circuits, can aLso be applied to radiators as shown in Figs 12 to 19 Figs. 12 and 13 show a panel type radiator 30 having verticaL exterior walls 31 and 32 and an internal central dividing wall 33 extending from the top 39 of the radiator to a point above the expanded bottom 34 of the radiator so as to provide a downwards flow channel 35 interconnected at bottom 34 to an upwards flow channeL 36. Immediately below the top 39 a horizontal inlet channel 37 is formed which is connected to the downwards flow channeL 35 and alongside channel 37 an outlet channel 38 is formed which is connected to the upwards flow channel 36 in the expanded top 39 of the radiator. Radiator inlet and outLets are connected to the respective channels 37 and 38.

Figs. 14 and 15 show a tubular radiator 40 with an upper horizontaL tube 41 divided into an outlet and inLet channel by means of a plate 42. Below tube 41 is a lower undivided horizontal tube 43. The horizontaL tubes are interconnected with verticaL tubes 44 divided by plates 45 so that flow is induced from a radiator inlet 46 in tube 41 down each downwards flow channel 47 into lower tube 43 and up each upwards flow channel 48 to upper tube 41 and radiator outlet 49.

Further radiators are shown in accordance with the invention in figs.16, 17 and 18.

These radiators are designed to provide a more effective heat exchange between radiator inlets and outlets than those in Figs 12 to 14 where only a single divider plate is provided.

Fig. 16 shows a radiator 50 with outer walls 51 and 52, an upper expanded portion 53 and a lower expanded portion 54. Two divider plates 55 and 56 are mounted vertically between walls 51 and 52 to define a singLe upper horizontal channeL 53 which continues into an inner downwards flow channel 57 and two outer outlet channeLs 53' which continue into outer upwards flow channeLs 58. A radiator inlet is connected to inlet channel 53 and a radiator outlet is connected to outlet channels 53' either at the same end of the radiator or at the other end of the radiator.

Fig.17 shows at 60 a radiator formed from square cross sectional tubing. The upper horizontal tube 61 is divided by plate 62 to provide a horizontal inlet channel 63 and a horizontal outlet channeL 64. Outer square vertical tube 65 has an inner coaxial vertical tube 66 which provides a downwards flow channeL 67connected to channeL 63 and an upwards flow channel 68 connected to channeL 64.a radiator inlet and outLet is connected at the same or opposite ends of channels 63 and 64. In a similar way to Fig 16, the radiator has a common undivided horizontal lower tube (not shown) connected to the bottom of vertical tubes 65 and 66 to provide an interconnection between channeLs 67 and 68.

Fig. 18 shows at 70 a radiator formed from circular cross sectional tubing. The connections are similar to those shown in Fig. 17 with an upper horizontal tube 71 divided by a horizontal pLate 72 to provide a horizontal inLet channel 73 and a horizontal outlet channel 74. An outer vertical tube 75 has an inner coaxial vertical tube 76 providing a downwards flow channel 77 connected to channel 73 and an upwards flow channel 78 connected to channel 74. A common undivided horizontal lower tube 79 is connected to the bottom tubes 75 and 76. A horizontal plate 80 in tube 79 supports the lower end of tubes 76 and perforations 82 in pLate 80 provide interconnections between channels 77 and 78.

Fig. 19 shows a possible installation for radiators shown in Figs. 12 to 18 in rooms defined upwardly by ceiling 90 and by floor 91.VerticaL paneL divided radiator 92 is connected by coaxial heat exchange pipes 93 and 94 to horizontal feed and return mains pipes 89 and 95. Low panel radiator 96 is similarly connected via heat exchange pipe 97 and 98. Either one or both upper corners of radiators 92 and 96 can be connected on each radiator to the feed and return mains. Radiator 99 is a similar radiator to 92 but is connected conventionally to pipes 89 and 95. A boiler is connected by an upwardly extending feed pipe 101 to the feed mains 89 and an upwardly extending return pipe 102 is connected to the return mains 95. Pipe 102 may be a single pipe or more than one pipe.

Referring to Fig. 20, it shows a system in which regenerative circulation is used to make pre-heated water available at a tap 106 while closed, according to the invention. The circuit comprises a boiler I used to heat radiators and also a water storage tank 13 for supplying taps with hot water. The circuit consists of similar upwardly, honzontaLly and downwardly extending supply and return pipes to those shown previously for heating circuits.

The coil Ia transfers heat from the boiler to the storage tank 13 causing circulation of the preheated water through the upwardly extending pipe 104 through the horizontaLly extending pipe 104a, which is a coaxiatly arranged part of the horizontally extending heat exchanger formed by pipes 104a and 105a, through to the downwardly extending co-axial pipe part 1 04b of the downwardLy extending heat exchange device to the outlet point 106a adjacent to the closed tap 106, upwardly through the annutus of the heat exchange device formed by pipes 104b and 1 05b, to the annuLus of the horizontally extending heat exchange device formed by pipes 104a and 105a, through pipe part 105c connecting to the upwardly extending annulus between the tank feed pipe 103 and pipe 105 down to the storage tank return point a' for recirculating. Water returning to the tank via the annulus around pipe 103 may pre-heat the feed water to the tank 13, simiLarLy pipe 103 may have a cooling effect on the returning water in the annulus and assist circulation Fig 20a shows the means by which the system in Fig 20 can supply a muLtipLe number of taps with a circulation of pre-heated water by extending pipe 104, and the annuLus between pipe 103 and 105.

Fig. 21 shows a circuit identical in arrangement to that in Fig. 20, but is used to provide a flow of pre-heated water to an open tap 106 through pipes previously used for the circulation of pre-heated water.

When a tap 106 is opened to atmosphere feed water enters tank 13 through pipe 103 at point a' impelLing pre-heated water in tank 13 through both the upwardly extending pipe 104 and the annutus between pipe 103 and pipe 105.

The pre-heated water flows upwardly through the verticalLy extending pipe 104, through the horizontally extending coaxial pipe 104a, which forms part of the horizontalLy extending heat exchanger, to the downwardLy extending pipe 104b, which forms part of the downwardly extending heat exchanger, to the open tap 106 outlet. Simultaneously a flow of pre-heated water to tap 106 WiLL occur from point f' at tank 13 through the upwardly extending annuLus between pipe 103 and pipe to the horizontally extending annuLus between pipes I 04a and 1 05a, via pipe 105c, to the downwardly extending annuLus between pipes 104b and 105b to the tap outlet.

The preheated water flowing into the annuLus from the tank at point 1' wilL be cooled to some extent on entering the annulus between pipes 103 and 105 by the water flowing downwardly through pipe 103 prior to its entry at point a' into tank 13. The amount of cooling WiLl depend on the ratio of the cross sectional areas of the annulus between pipe 103 and pipe 105, and pipe 103, and, possibly, also on the rate of flow of water into the tank; this may, to some extent be controlled at the shut-off/ control valve' at point b' of pipe 103.

Fig. 21a shows the means by which the system shown in Fig 21 can supply a multiple number of pipes with a flow of pre-heated water by extending pipe 104 and the annulus between pipes 103 and 105.

Fig. 22 shows a system which is identical to Figs. 20 and 20a except for the embodiment of check vaLves 108 in pipe 107, and 109 in pipe 11 0.The balL 112 in check valvelOB (Fig.28), with tap(s) 106 closed, remains seated in the closed position to ensure pre-heated water is circulated from tank 13 through pipe 104, and not pipe 107, to the re-circulation point 106a via the extended horizontal pipe 104a. The ball 113 in check vaLve 109 (Fig. 28), with tap(s) cLosed, remains seated in the open position allowing pre-heated water to re-circulate around it and back into tank 13 for recycLing at point f', via the annulus between pipes 103 and 105. Fig 22a shows the means by which a multiple number of pipes can be

supplied with a circulation of pre-heated water by extending the pipes 104 and 107 and the annulus between the pipes 103 and 105 shown in Fig.22.

Fig. 23 shows a system which is identical to Fig. 21 except for the inclusion of check valves 108 in pipe 107 and 109 in pipe 110. The ball 112 of check valve 108 (Fig.29), with one or more taps 106 open, is Lifted by water flowing into the tank 13 at point a' to the open position to ensure water flows through pipe 107 to the open tap(s) via the horizontal annulus between pipes I 04a and I 05a, and not through the annulus between pipes 103 and 105. The balL 113 in check vaLve 109 (Fig.29), with one or more tapsl06 open, is lifted by water flowing into the tank 13 at point a' to its closed position, to ensure water flows through pipe 104 and not through the annulus between pipes 103 and 105. The discharge from taps 106 is matched by the water flowing into the tankl3 via pipe 103, according to the invention. With check valves embodied the cooLing effect as described for Fig.21 is avoided.

Figs. 24 and 24a show another heating system for circulating pre-heated water as described in Fig.20, but with a manifold device embodied comprising of items 118,119 and 120. Item 118 is a distribution chamber for circulating water from the storage tankl 3 to a multiple number of tapsl 06. Item 119 is a collection chamber for water circulating back from a multiple number of tapslo6 to the storage tankl3.

Item 120 separates the flow and return circulation chambers. The manifold device is shown as square in section but may be round or of any preferred shape.

Fig.25 shows a system identical in arrangement to that in Figs.24 and 24a but is used to provide a flow of pre-heated water to open tap(s) 106 through pipes previously used for the circulation of pre- heated water as shown in Fig 24 and 24a. Chamber 118 colLects the flow of pre-heated water from pipe 104 and chamber 119 collects the flow of pre-heated water from the annulus between pipes 103 and 105 via pipe 114. Both chambers then distribute the flow of heated water to the open tap(s) 106 via the horizontal pipes 104a and the annulus between pipes 104a and 105a. When all taps are closed the system WILl then continue to re-circuLate pre-heated water as described in Figs 24 and 24a.

Fig. 26 shows a heating system identicaL to that in Fig. 24 except for the inclusion of check valves 108 in pipe 107 and 109 in pipe 110.The function of the check valves 108 and 109 with taps 106 closed is as described in Fig.22, according to the invention.

Fig. 27 shows a heating system which is identical in arrangement to Fig. 26 when used for supplying a fLow of pre-heated water to more than one open taplO6. The function of the check valves 108 and 109 with taps 106 open is as described in Fig.22 For Figs. 20 to 27 the discharge from tapsi 06 is matched by the water flowing into the tanki 3 via pipe 103, according to the invention.

For systems shown in Figs. 20 to 27, when one or more tapsl 06 are opened circulation of preheated water to other closed taps will cease until all taps are closed. This situation may not be suitable for larger type premises where severaL taps could be in use at any one time. Fig. 31 shows a type of storage tank that wilL enable multiple numbers of taps to be individually connected to it to ensure each closed tap wilL receive uninterrupted circuLation of pre-heated water; this will not be the case when sharing a supply line 104 and/or a return annuLus in pipe 105.

As shown in Figs. 20 to 27, a' is the water inlet point to the tank, b' is a shutI off/flow control vaLve, c' is the system drain point, d' is a shut-off valve, e' is possible air venting/expansion position, and f' is the system inlet point to the storage tank.

Fig. 28 shows the positions of ball valves 112 and 113, and the direction of water circulation, for taps closed condition. Ball valve 112 is shown in the cLosed position and ball valve 113 in the open position, according to the invention; (ref Fig. 22) Fig. 29 shows the positions of baLl vaLves 112 and 113, and the direction of water fLow for taps open condition. Ball vaLve 112 is shown in the open position and ball valve 113 in the closed position, according to the invention; (ref Fig.23).

Fig.30 shows an enLarged view of ball valve 113 in its open positton,( allowing water to circulate around the ball), when a tap is opened; ref Figs.22 and 23).

Fig. 31 shows a storage tank I 3a suitable for providing several separate supply and return lines for the purpose of, re-circuLating pre-heated water between the tank and tapslo6 when closed, and for supplying a flow of pre-heated water to taps 106 when opened. Individual pipe runs can be arranged for each circuit where the feed Line 103 supplying water to the tank wiLl use connections at position 123, the supply pipes 104 for the circuits wilL use connections at positions 125 and the system return line 105 will use connections at positions 124. Connections shown at 128, connect the coil in the tank to the suppLy pipe 126 from the boiler and the return pipe 127to the boiler. Individual pipe runs WILL dispense with the annulus between pipes 103 and 105. The pipe 105c WILL connect to individual pipes 105 instead of the annulus arrangement as shown in Figs, 20, 20a, 21, 21a,22 and 22a.

ALthough this arrangement WILL avoid the cooLing effect of pipe 103 on the water in the annulus between pipe 103 and 105, as described in Fig. 21a, it may also remove any possible assistance to flow from the heat exchange process between pipe 103 and the annulus between pipe 103 and 105, as described for Fig. 20.

If an annulus arrangement is required to provide heat exchange between pipes 103 and 105 to assist circulation back to the tank then suitable connections can stiLL be made to tank 13a using connections 123 and 125 in the manner shown in Figs. 20, 20a, 21, 21a, 22, 22a, 23, 23a, 24 and 24a, 25 and 25a, 26, 27 and 34. The use of check vaLves 108 and 109 can still be used in the manner shown in Figs. 22 and 23.

A manifold arrangement, with or without check valves, can stiLL be used with an annuLus type connection to tank 1 3a, to distribute water to separate taps in individuaL pipe runs in similar manner to that shown in Figs. 24, 24a and 25, 26, 27and Fig.38. In the type of circuit arrangements shown, circulation of pre-heated water to cLosed taps wiLL cease when another tap is opened.

Fig. 32,33,34 and 35 show diagrammatically a system arrangement for using solar power to drive a regenerative heating system using solar collectors and photovoLtaic panels. As mentioned previously, a regenerative system as described herein is suitabLe for use with the arrangement shown in this figure.

The circuit diagram shown comprises 4 solar colLectors 132 and 4 photovoLtaic panels 133 for a roof installation which is connected to a regenerative circuit simiLar to those described in the preceding figures. The circuit can be used to provide heat to a Large mass, which could be part of the fabric of the building, and also to a domestic water suppLy tank similar,or identical, to 13 or 13a as shown in Fig. 34.

The circuit could aLso be used for under-fLoor heating in known manner.

Heat is circulated up through the solar coLLectors 132 via pipe 104 to the highest panel and to the horizontally extending pipe I 04a, which is part of the horizontally extending heat exchanger, formed by pipe I 04a being co-axially arranged in pipe 105a, pipe 104a connects to a downwardLy extending pipe 104b, which is part of the downwardly extending heat exchanger, formed by pipe 1 04b being co-axiaLLy arranged in pipe 105b, to the Lowest point 106a (Figs. 32 and 35) for recycling through the annuLus formed by pipe 104b and pipe 105b, back to the high horizontally arranged extending annuLus of the heat exchanger, formed by pipe I 04a and pipe 1 05a, via pipe I 05c to connect with the upwardLy extending pipe 105 down to the return inlet of the Lowest solar paneL at point 4f' for re-cycLing.

On entering pipe 1 05a the water in pipe I 04a transfers some heat to pipe 1 05c. The amount of heat transferred WiU depend on the ratio of the cross-sectional area of the annulus formed by pipe 104a and pipe 105a and the cross-sectional area of pipe 104a. The heat being transferred to the system from the solar panels wilt progressively increase the temperature of the water in the circuit.

AdditionaL heat can be generated in the circuit by instalLing heating elements 134 which are powered by the photovottaic panels 133. Where it is required to provide assistance for circulation, particularly when the system is required to be used in buildings with more than one story, a circulation device 135 driven by a photovoltaic panel may be installed. This device can either be installed in paralleL, or in series as shown in Figs. 32 and 33.

Circulation may also be assisted by installing a similar arrangement to that shown in previous circuits by combining a water feed pipe 103 with the return line of the system 105 to form an annutus around pipe 103 to obtain some benefit from the heat exchange process, as described for Fig. 20.

Heat supplied by the system can be stored during summer months for use during cold winter days by storing it in a large mass, possibly in the fabric of the building.

The diagram in Fig. 32 shows, by way of example, a section through an interior walL comprised of a heat absorbing mass which divides two rooms, an air gap 131, insulation Lining 129 and air vents 128.

The heat to be stored is transferred to the heat absorbing massi 30 from the outer diameter of the downwardly extending heat exchanger formed by pipes 1 04b and 105b. Several heat exchange units can be inserted into the heat absorbing mass to facilitate even distribution of heat exchange. A high mass at low temperature is capable of supplying or storing as much heat as a low mass of higher temperature.

It may also be possible to provide a more even distribution of heat into the mass 130 by means of connecting the outside diameters of each of the vertically extending externaL pipes 1 05b of the heat exchanger to good conducting ties which extend horizontalLy a Long the mass 130.

The insuLation lining 129 is intended to prevent heat from the mass 130 being transferred to the rooms either side of the mass during the summer days. The thermal gradient across the insulating material shouLd be such as to maintain comfortabLe room temperatures during summer days. The temperature difference between the mass and a comfortable room temperature will determine the thickness of insulation to be used. It is also important for the external waLls and surfaces of the building to be suitably insulated to gain the greatest benefit.

During winter days the room temperature can be controlled by adjusting the vent 136 opening.

An alternative heat store of high mass could be a sotid floor with underfloor heating installed in known manner using the principLes and methods of the regenerative system as described by this invention.

Figs. 36 and 37 show alternative methods of negotiating bends, or making connections, between honzontaL and vertical pipe runs. The method shown in Fig. 36 is suitable for pipe material which is more flexible than the usual rigid tubing and has suitable thermal properties. Fig. 37 is most suitable for rigid pipes also with good thermal qualities.

Fig. 38 shows a number of taps installed in series in an annuLus arrangement similar to the arrangements shown previously in Figs 20 to 27. The figures show the flow-path with two taps 106 open. The water to the taps wilt be drawn from the annulus but, the flow of water to the taps wilt be from opposite directions. As shown, water flows from the direction of the tank and also from the open end 1 06a of pipe I 04a.

This arrangement may ensure a more evenly balanced flow to aLL taps when opened.

Preheated water wiLl continue to re-circulate around the circuit when all taps are closed; as in systems shown in Figs. 20, 20a, 22 and 22a. This arrangement may aLso be used with a variety of other different circuits using the storage tank I 3a as described in Fig.31.

Claims

1. A heating system comprising a boiler for heating a liquid, a feed pipe conducting a heated liquid from the boiler to at (east one heat dispenser and a return pipe returning cooled liquid to the boiLer for recycling, the feed and return pipes extending upwardLy from the boiler and downwardly towards the heat dispenser, heat exchange means arranged to transfer heat from the Liquid in the downwardLy extending part of the feed pipe to the liquid in the downwardly extending part of the return pipe to at least partially equalise the liquid temperatures therein wherein substantially horizontal feed and return and return mains extend between the upwardly extending pipes from the boiler and the heat exchange means.

2. A system as claimed in claim I wherein the heat dispenser is below or level with the boiler.

3. A system as claimed in claims I or 2 wherein the heat exchange means comprises two substantially co-axial channels.

4. A system as claimed in cLaim 3 wherein the outer and inner channels are substantially standard size tubing as in common use with existing systems.

5. A system as claimed in any one of claims 1 to 4 wherein the feed and return mains are accommodated at, or above, ceiling Level above the boiler.

6. A system as claimed in any one of the claims in 1 to 5 wherein a pLurality of return pipes is provided which extend from the horizontaL mains to the boiler.

7. A system as claimed in any one of the claims 1 to 6 wherein the heat dispenser is a radiator comprising an upper horizontaL outlet channel, and upper horizontaL inLet channel, a lower horizontaL conduit and at least one vertical downwards flow channeL connecting the inlet channel and the Lower conduit and at Least one verticaLLy upwards flow channeL connecting the lower conduit and the outLet channel, means being provided to connect the inlet and outlet channels to the feed and return pipes.

8. A system as claimed in claim 7 wherein the upper horizontal outlet channel and upper horizontaL inlet channel are formed within a divided upper part of the radiator.

9. A system as claimed in cLaims 7 and 8 wherein one or more vertical dividing plates extending upwardLy from the lower conduit form the fLow channels.

10. A system as cLaimed in claim 7 or 8 wherein a pair of coaxial tubes form the flow channels. fl

11. A heat dispenser being a radiator as set out in cLaims 8 to 10.

12. A heating system substantiaLly as described with reference to Figs I to 19 of the accompanying drawings.

13. A radiator as claimed with reference to Figs 12 to 18 of the accompanying drawings.

14. A heating system comprising a hot water storage tank containing a sealed heating coil fed by heated water from a boiler, a downwardly extending feed line to replace water discharged from the storage tank, a co-axial annulus formed by a feed line and return pipe of the circuit for colLection of pre-heated water previously circulated from the storage tank to a closed connection adjacent to a closed tap for its re-circulation back to the storage tank, a upwardly extending feed pipe from the storage tank connecting with a horizontally extending coaxial heat exchanger formed by a inner supply pipe and a outer return annulus between supply and return pipes to facilitate contra-flow circulation of pre-heated water to a closed tap, a downwardly extending coaxiaL heat exchanger formed by a inner supply pipe and a return annulus between supply and return pipes to facilitate contra-flow circulation of pre-heated water from the closed tap position for re-circulation back to the tank.

15. A system as claimed in cLaim 14 wherein one or more closed taps are supplied with pre-heated water circulated from a storage tank.

16. A system as claimed in claim 14 with check valves embodied wherein a closed tap is supplied with pre-heated water circulated from a storage tank.

17. A system as claimed in claim 16 wherein one or more closed taps are supplied with pre-heated water circulated from a storage tank.

18, A system as claimed in claim 14 with a manifold device embodied for circulating pre-heated water from a storage tank to more than one closed tap and also for coLlecting returning pre-heated water from a connection adjacent to more than one closed tap, for its return to the storage tank for recycLing.

19. A system as claimed in claim 18 with check valves embodied wherein more than one closed tap is supplied with pre-heated water circulated from a storage tank.

20. A system as claimed in claim 14 wherein a open tap is supplied with a flow of pre-heated water through pipes previously used for recirculating preheated water to a closed tap.

21. A system as claimed in claim 15 wherein one or more open taps are supplied with a flow of pre-heated water through pipes previously used for recirculating per-pre-heated water to more than one cLosed tap.

22. A system as claimed in cLaim 17 wherein a open tap is supplied with a flow of pre.heated water through pipes previously used for recirculating pre-heated water to a closed tap.

23. A system as claimed in claim 17 wherein one or more open taps are supplied with a flow of pre-heated water through pipes previously used for recirculating pre-heated water to one or more closed taps.

24 A system as cLaimed in claim 18 wherein more than one open tap is supplied with aftow of pre-heated water through a manifold device and pipes previously used for recirculating pre-heated water to one or more closed taps.

25. A system as claimed in cLaim 19 wherein more than one open tap may be supplied with a flow of pre-heated water through check valves, a manifold device and pipes previously used for recircuLating pre-heated water, to one or more closed taps.

26. A system as in claims 14 to 17 and 20 to 23 wherein one or more taps are each independentLy connected to contra-fLow heat exchange devices either for re-circuLating pre-heated water to cLosed taps or for providing a continuous flow of pre-heated water from a storage tank with multiple connections, when one or more taps are opened.

27.Systems as claimed in claim 26 wherein the water feed lines to the tank may each be independent of an annulus return and be connected direct to a storage tank with connections for several separate pipe runs of the system, and, Likewise, the return pipe of the system may aLso be independent of the water feed Line to the tank if preferred.

28. Systems as claimed in claim 18 and 19 and 27 wherein an annulus type arrangement is used for re-circulating re-heated water, or for providing a flow of heated water, to more than one pipe when connected to a tank providing connections to either individual pipes or co-axial pipes using an annulus arrangement.

29. A system comprising solar coLLectors and photovoltaic panels to drive a regenerative circuit for the purpose of providing heat for immediate use, or to a storage facility, a domestic hot water supply system or to a underfLoor heating system, or other such thermal devices including those covered by accompanying drawings of this invention.

30. Systems substantially as described with reference to Figs. 20 to 38 of the accompanying drawings.

Amendments to the claims have been filed as follows: 1. A system using regenerative heat exchange devices to create circulation of heated water in cLosed circuits comprising a hot water storage tank containing a sealed heating coil fed by heated water from a boiler, a downwardly extending feed tine to the water storage tank, a coaxial return annutus formed by the feed line to the tank and a return pipe to the tank for returning pre-heated water previously circulated to a connection adjacent to a closed tap, an upwardly extending supply pipe from the storage tank connecting with a honzontaLLy extending regenerative heat exchange device comprising separate supply and return channeLs of the circuit for circuLation of pre heated water to and from a closed tap, a downwardly extending regenerative heat exchange device comprising separate supply and return channels to enable contra-flow circulation of pre- heated water from the closed tap position back to the tank for recycling via the coaxial return annutus.

2. A system as claimed in claim 1 wherein the separate suppLy and return channeLs of the regenerative heat exchange devices are comprised of co-axial pipe arrangements or separate adjacent channels.

3. A system as claimed in cLaim 2 wherein one or more closed taps are supplied with pre-heated water circulated from a storage tank.

4. A system as claimed in claim 3 with check valves embodied wherein a closed tap is supplied with pre-heated water circuLated from a storage tank. * ..

5. A system as claimed in claim 4 wherein one or more closed taps are supplied with *.. preheated water circulated from a storage tank.

6. A system as claimed In claim 3 with a manifold device embodied for circulating * pre-heated water from a storage tank to more than one closed tap and also for collecting returning pre-heated water from a connection adjacent to more than one closed tap, for its return to the storage tank for recycling. S... * S.

::, 7. A system as claimed in claim 6 with check valves embodied wherein more than * one cLosed tap is supplied with pre-heated water circuLated from a storage tank.

8. A system as cLaimed in claim 2 wherein an open tap is supplied with a flow of pre-heated water through pipes previously used for recircuLating pre-heated water to a cLosed tap.

9. A system as claimed in claim 8 wherein one or more open taps are supplied with a flow of pre-heated water through pipes previously used for recirculating pre-heated water to more than one closed tap.

10. A system as claimed in claim 4 wherein a open tap Is supplied with a flow of preheated water through pipes previously used for recfrcuLating pre-heated water to a closed tap.

11. A system as claimed in claim 10 wherein one or more open taps are supplied with a flow of pre-heated water through pipes previously used for recircuLating pre-heated water to one or more cLosed taps.

12. A system as claimed in claim 6 wherein more than one open tap is supplied with a fLow of pre-heated water through a manifold device and pipes previously used for redrcuLating pre-heated water to one or more cLosed taps.

13. A system as claimed in claim 7 wherein more than one open tap may be suppLied with a flow of preheated water through check valves, a manifold device and pipes previously used for recirculating preheated water, to one or more cLosed taps.

14. A system as in anyone of claims 2 to 5 or 8 to 11 wherein one or more taps are each independently connected to contra-flow heat exchange devices either for re-circulating preheated water to closed taps or for providing a continuous flow of pre-heated water from a storage tank with multiple connections when one or more taps are opened.

15.A system as claimed in claim 14 wherein the water feed Lines to the tank may each be independent of an annulus return and be connected direct to a storage tank with connections for several separate pipe runs of the system, and, Likewise, the return pipes of the system may also be independent of the water feed Line to the tank if preferred.

16.A system as cLaimed in claim 6, 7 or 15 wherein an annulus return arrangement is used for re-circulating preheated water, or for providing a flow of heated water, to more than one pipe when connected to a tank providing connections to either individual pipes in series or in parallel and aLso to co-axiaL pipes for an annulus return arrangement.

17. A system as claimed in claim 2 which comprises;-solar collectors and photovoLtaic panels to drive a regenerative circuit for the purpose of providing heat for immediate use, or to a storage facility, a domestic hot water supply system or to a underftoor heating system.

18.Regeneratlve systems substantially as described with reference to Figs. 20 to 38 of the accompanying drawings.

19.A system as claimed in claim 2 which comprises a boiler to drive a regenerative * : circuit for the purpose of providing continuous circulation of heated fluid to room heating devices in addition to providing heat to a domestic water suppLy.

20.A heating system as claimed in cLaim 19 comprising a feed pipe conducting a heated liquid from the boiler to at Least one heat dispenser and a return pipe returning cooLed liquid to the bolter for recycling, separate feed and return pipes extending upwardly and horizontaLLy from the boiLer to downwardly extending coaxial pipes to the heat dispenser with heat exchange means arranged to transfer heat from the liquid in the downwardly extending part of the feed pipe to the liquid in the downwardly extending part of the return pipe to at least partially equalise the liquid densities therein.

21. A system as cLaimed in cLaim 20 wherein the heat dispenser is LeveL with the boiler.

22. A system as claimed in claim 20 wherein the heat dispenser is below the boiler.

23. A system as claimed in claim 21 or 22 wherein heat is exchanged between two substantially coaxial channeLs.

24. A system as cLaimed In claim 23 wherein the outer and inner channels are substantially standard size tubing as in common use with existing systems.

25. A system as claimed in any one of claims 20 to 24 wherein the feed and return mains are installed at, or above, ceiling level above the boiler.

26. A system as cLaimed in any one of the cLaims in 20 to 25 wherein a pluraLity of return pipes is provided which extend downwardly from the horizontal mains to the boiLer.

27. A regenerative system as claimed in any one of the claims 20 to 26 wherein the heat dispenser is a radiator comprising an upper horizontaL outlet channel, and upper horizontaL inlet channel, a lower horizontal conduit and at Least one verticaL downwards flow channel connecting the inlet channel and the Lower conduit and at Least one vertically upwards flow channel connecting the lower conduit and the outlet channeL, means being provided to connect the inLet and outlet channeLs to the feed and return pipes.

28.A system as claimed in claim 27 wherein the upper horizontaL outlet channeL and upper horizontal inlet channel are formed within a divided upper part of the radiator. Un I..

* 29.A system as claimed in claim 27 or 28 wherein one or more vertical dividing plates extending upwardly from the Lower conduit form the flow channels.

30.A system s cLaimed in claim 27 or 28 wherein a pair of co-axial tubes form te flow channels.

31.A system as claimed in claim 17 wherein the arrangements shown in Figs. 12, 14, 16, 17 and 18 may be used for heat storage purposes as well as, or instead of, the coaxial arrangement shown in Figs. 32 and 35. * S. S. a * S. * a.. * S SSS. S. * . * .5S

S S.. * S*S *5

S S. * * S S.