GB2352506A

GB2352506A - A water heating system

Info

Publication number: GB2352506A
Application number: GB0014034A
Authority: GB
Inventors: Richard Hanson-Graville
Original assignee: DEDICATED PRESSURE SYSTEMS Ltd
Current assignee: DEDICATED PRESSURE SYSTEMS Ltd
Priority date: 1999-06-16
Filing date: 2000-06-08
Publication date: 2001-01-31
Anticipated expiration: 2020-06-08
Also published as: GB9914072D0; GB0014034D0; GB2352506B

Abstract

A water heating system comprises a heat exchanger 3 for transferring heat form a primary hot water circuit to a secondary cold water circuit at mains pressure. The water in the primary circuit is heated by a heat source. The heat exchanger 3 has an inlet 4 and a return line 5 for hot water from the primary circuit. The heat exchanger also has an inlet 6 and an outlet line 7 for water in the secondary circuit. The secondary water circuit has a water flow sensing switch 8. The flow sensing switch 8 operates to open a valve means 9 in the heat source return line 5 thus allowing hot water from the heat source to flow through the heat exchanger 3 to produce heating of the mains water supply drawn of through line 7. The heat source may be a boiler with a heated water feed to a central heating system or to a hot water tank. The valve means may comprise a solenoid valve in the boiler return line 5. The valve may be a three port solenoid valve. The heat exchanger may supply hot water to a shower or to taps. The heat exchanger 3 may be a plate heat exchanger.

Description

2352506 Title Water heating method and aDparatus This invention relates to

a water heating method and an apparatus for carrying out the method. This invention is more particularly concerned with a method an apparatus for indirectly heating a mains water supply.

An object of this invention is to provide a method and apparatus by means of which a conventional domestic heating system may be easily adapted to the requirements for direct heating of water at mains supply pressures.

According to this invention there is provided a water heating system having a heat source, such as a boiler, with a heated water feed to, for example, a central heating system or hot water tank, and a return flow back to the heat source, characterised by a heat exchange unit having an inlet for mains pressure water feed to, and through, a heat exchange matrix and thence to an outlet for hot water supply at mains pressure, the heat exchange matrix being fed, for indirect heating of the mains water, through a heating water feed connected with the boiler heated water feed and a heating water return connected with the boiler return flow, a flow sensing switch being provided in the mains pressure water circuit of the heat exchanger and connected so as to open a valve means in the boiler heating water circuit to the heat exchanger when flow is sensed in the mains pressure supply and to close said valve on the flow being interrupted.

With this arrangement according to the invention an existing hot water supply system having a low pressure circuit, for example one fed from a water storage tank, or feeding a central heating system, can be readily and safely 2 adapted to supply a direct mains hot water supply for a shower or the like on demand. The arrangement avoids the need for a mass of water in a tank to be kept continually hot to supply intermittent needs.

The valve means may comprise a simple solenoid valve in the boiler return feed to the heat exchanger thus avoiding any interruption to the existing boiler circuit. In a modification the valve is a three port solenoid valve which may selectively switch the boiler hot water feed to the heat exchanger or the existing boiler hot water circuit thus temporarily cutting out the heating system to allow the boiler to supply the hot water circuit exclusively.

Further and preferred features are disclosed in the drawings showing embodiments by way of examples. Features relating to the existing hot water system to be modified by this invention are omitted.

In the drawings.- Figs. 1 to 6 show different configurations and embodiments of systems and apparatus according to this invention, Fig. 7 shows an installation for hot water supply to taps, and Fig. 8 shows an installation for supply to a shower.

Referring firstly to Fig. 8 of the drawings there is shown the hot water supply pipe 1 from a conventional boiler and feeding, for example, a hot water storage tank or central heating system. The return flow pipe from the storage tank is shown as 2. This system is under low pressure typically fed by a storage tank.

A plate heat exchanger 3 has two internal circuits which are mutually separate but connected for heat transfer through a plate-like heat exchange matrix. One circuit has an inlet 4 for hot water from the boiler pipe 1 and an 3 outlet 5 for return to the boiler return 2. The other circuit has an inlet 6 for water supply at mains pressure and an outlet for heated water 7 to feed the domestic supply such as taps.

The high pressure hot supply 7 includes a pressure or flow sensing switch 8 which is actuated as soon as flow is detected for example due to a tap being opened. The switch 8 operates to open a solenoid valve 9 in the boiler return 5 thus al lowing hot water flow from the boiler through the heat exchanger 3 to produce heating of the mains supply drawn-off through line 7.

A flow balancing valve 10, Fig. 7, may be provided in the boiler feed 4.

io When the flow through outlet 7 stops, as sensed by the switch 8, then the solenoid valve 9 closes preventing unnecessary heat drain on the boiler supply.

Fig. 8 shows a version intended for a shower supply as well as taps and is generally the same but here the solenoid valve 11 is a three port unit and arranged so that on actuation of the flow switch 8 the boiler hot water feed 1 is redirected to the heat exchanger through the inlet 4 and the feed to hot supply 1 a is closed. Thus the whole of the boiler output is available during use and the central heating system is bypassed.

The heat exchange unit 3 and associated valves is a self-contained unit and is adapted to be fitted into an existing supply. This is a feature of this invention.

Figs. 1 to 6 show, in diagrammatic form, various configurations of the feeds and valves and similar references are used as in Figs. 7 and 8. It may be desirable to include filters in the flow.

4 In the arrangements shown the flow switch 8 detects the flow of domestic water and opens the solenoid valve 5, thus allowing hot water from the boiler to flow through the heat exchanger.

The arrangement of Fig. 6 is for a shower and in this embodiment the 5 three port valve 11 diverts the whole boiler hot water flow through the heat exchanger3.

Claims

CLAIMS:

1 A water heating system having a heat source with a heated water feed to a consuming means and a return flow back to the heat source, 5 characterised by a heat exchange unit having an inlet for mains pressure water feed to, and through, a heat exchange matrix and thence to an outlet for hot water supply at mains pressure, the heat exchange matrix being fed, for indirect heating of the mains water, through a heating water feed connected with the heated water feed and a heating 10 water return connected with the heat source return flow, a flow sensing sWtch being provided in the mains pressure water circuit of the heat exchanger and connected so as to open a valve means in the heat source heating water circuit to the heat exchanger when flow is sensed in the mains pressure supply and to close said valve on the flow being 15 interrupted.

2. A water heating system in accordance with claim 1, wherein the heat source comprises a boiler with a heated water feed to a central heating system or to hot water tank.

3. A water heating system in accordance with claim 1 or 2, incorporated 20 into an existing hot water supply system having a low pressure circuit, for example one fed from a water storage tank, or one feeding a central heating system, and arranged to supply a direct mains hot water supply for a shower or the like on demand.

4. A water heating system in accordance with any preceding claim, 25 wherein the valve means comprises a solenoid valve in the boiler return 6 feed to the heat exchanger operating without interruption to the existing boiler circuit.

5. A water heating system in accordance with claim 4, wherein the valve is a three port solenoid valve which may selectively switch the boiler hot water feed to the heat exchanger or to the existing boiler hot water circuit thus temporarily cutting out the heating system to allow the boiler to supply the hot water circuit exclusively.

6. A water heating system as described herein and exemplified with reference to the drawings.