A HEATING SYSTEM

The invention relates to a water heating system using a water heater and to apparatus for heating water, particularly a gas water heater.

Gas water heaters usually comprise a gas burner which heats water passing through pipes when the burner is fired. While this heats the water, it is at the expense of passing a large amount of hot exhaust gases to ambient atmosphere. This is brought about by the pipes, usually copper pipes of the gas water heater, generally being unable to utilise the heat generated by the burners, particularly over a relatively short time when there is a call for more or less instantaneous hot water when say a shower is turned on. Thus the heating efficiency is low, and a large proportion of heat will be exhausted to the environment, for example outdoors.

It is an object of the invention to seek to mitigate this disadvantage.

According to the invention there is provided a system including a water heater adapted for mounting internally of a space and an exhaust port for directing exhaust gases exteriorly of the space, and a heat exchanger, having water pipes connected with the water heater mounted in the exhaust port.

The heater may be a gas, oil or electric water heater.

Using the invention it is possible to provide that less gas, oil or electricity is required to heat the water to a desired temperature, and therefore less energy is used for a given supply of hot water.

The heat exchanger may comprise a modular unit adapted for mounting in the port and for connection with the water pipes of the heat exchanger. This provides a compact system, and one in which the unit may be retrofitted.

The modular unit may comprise a body with a plurality of water carrying pipes. The body may comprise a hollow rectangular parallelepiped, the said pipes being suitably mounted at a plurality of boundary surfaces thereof.

There may be water carrying pipes at three of the walls, and there may be an inlet and an outlet for water to the pipes at one end face of the unit. This provides for relatively easy connection with pipes of the water heater.

There may be means adapted to distribute exhaust gases to the walls of units suitably comprising a plurality of fins. These can direct exhaust gases evenly to the walls of the unit, particularly when the fins extend transversely of an inlet to the unit.

Suitably, the fins may extend substantially horizontally across the inlet to the unit.

The pipes at least one of the walls of the unit may comprise sinuously arranged pipes.

The water heater may be mounted on an interior surface of an outside wall defining a boundary of the space and through which the outlet port passes.

According to a further aspect of the invention, there is provided a heat exchanger unit adapted for mounting an outlet port for exhaust gases from a water heater, comprising a through passage for exhaust gases, and boundary walls defining the through passage in which heat exchanger elements are mounted.

The heat exchanger element may comprise pipes adapted to carry water and for connection with water pipes of the water heater.

A combustion element may also be provided. Further, a device for absorbing heat from the combustion element may be provided, the heat exchanger associated with the device and adapted for the passage of water to be heated, whereby the water is heated indirectly by the combustion element, via the heat exchanger.

Suitably, there may be a further heat absorbing device and associated heat exchanger. This increases efficiency, as does the provision of a yet further heat absorbing device and associated heat exchanger.

The heat absorbing device(s) may comprise an array of heat absorbing plates, suitably metal plates, and particularly copper plates.

The heat absorbing device(s) may be mounted in a combustion chamber for the combustion element. This also provides for efficient utilisation of heat from the combustion element.

The yet further heat absorbing device and associated heat exchanger may be downstream of the combustion chamber.

The first mentioned heat absorbing device being located at a downstream part of the apparatus.

There may be piping for water to be heated including an inlet pipe and an outlet pipe.

The inlet pipe may be bifurcated, one limb passing to the further heat absorbing device and the other limb passing to the first-mentioned heat absorbing device.

Suitably, there may be a water flow sensor at the water inlet pipe.

The combustion element may comprise a gas-fired element. This provides an easily controllable combustion element, particularly when there is a gas flow controller for controlling flow of gas to the gas-fired element.

There may be an exhaust fan for exhausting gases of combustion to ambient atmosphere, and the exhaust fan may comprise separate exhaust fan motor.

The exhaust fan and motor may be internally of a casing of the apparatus and downstream of the yet further heat absorbing device.

Suitably, there may be means for detecting the temperature of heated, outflow, water.

The plates may project from and extend substantially at right angles to the associated respective heat exchanger. This provides for efficient heat transfer to the heat exchanger(s).

A system embodying the invention, is hereinafter described, purely by way of example, with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic elevational view from one end of a modular unit of the system;

Fig. 2 is a schematic perspective view of the module of Fig. 1;

Fig. 3 is a schematic elevational view of the system;

Fig. 4 is a schematic side view of the system of Fig. 3;

Fig. 5 is a perspective view to an enlarged scale of a part of the system of Fig. 4;

Fig. 6 is an elevational view of a further embodiment; and

Fig. 7 is an elevational view of a further embodiment.

Referring to the drawings, there is shown a system 1 including a water heater 2 in the embodiment a gas water heater, adapted for mounting internally of a space 3 and an exhaust port 3' for directing exhaust gases exteriorly of the space 3 and a heat exchanger 4 having water pipes 5 connected with the water heater 2 mounted in the exhaust port 4.

hi the embodiment the gas water heater has a body 6 which is mountable on a wall 7 of the space 3 such as a room of a domestic dwelling, the wall 7 being an exterior wall through which the exhaust port passes 4. The gas water heater 2 includes a gas burner 8 supplied with gas from a gas supply, not shown, burning flames 9 providing heat for heating water passing through pipes or piping 10 of any suitable material such as copper pipes arranged to be exposed to heat from the flames 9 to heat the water as it passes therethrough for use in radiators, at a shower, bath, or any combination thereof fed via outlet pipe 11.

There is waste heat carried in and by the exhaust gases from the flames 9 which normally exit via the exhaust port 4. In the embodiment, the heat is utilised by passing through the heat exchanger unit installed in the exhaust port 3'. The unit 4 comprises a body 12, suitably of metal, of rectangular parallelpiped configuration having a through passage 13 for exhaust gases and in or at the walls 14 of which are mounted heat exchanger elements in the form of the water carrying pipes 5 which form a continuous network over three walls 14. There is an inlet 15 and an outlet 16 for water to the network in a front (inner in use) face 17 of the unit 4, the inlet 15 being connected to a source of water to be heated from a source (not shown) such as the mains, and the outlet 16 being connected at a connector 18 with the pipes 10 of the water heater 2.

In order to provide for even distribution, and thus utilisation, of the exhaust gases, the unit 4 includes at or adjacent the front face 17 distribution elements such as in the embodiment transversely arranged fins 19 extending across the inlet 13 to the through passage.

In use, water from the source passes along piping to the Met 15 of the unit 4 through the heat exchanger water elements 5 and out through the outlet 16 to the gas water heater 2 to pipes 10. When there is a call for heated water, the burner 8 fins and heats the water in the water heater pipes 10. The exhaust gases heat the water in the heat exchange unit 4 in the exhaust port 3' so that when it arrives in the water heater 2, it is already warm and does not need as great an amount of energy as hitherto in order to heat it to the desired temperature. It will be understood that the system 1 is therefore energy efficient. Further, the heat exchanger unit 4 is modular and can be retro-fitted or fitted as "new build" in the exhaust port 3'. In either case, there is no, or at least minimal, disruption to the gas water heater 2, so that no modification thereof is required as the connection 18 already exists, being the entry point for water to be heated.

Referring now to the embodiment 100 of Fig. 6, this is similar to the embodiment of Figs. 1 to 5, except that to reduce heat loss to ambient atmosphere from the outer casing 101 of the gas water heater 8, heat insulation in the form of a layer of heat insulation material 102 is applied to an outer surface of an outer metallic cover 103 of the

combustion chamber. The heat from the heated air generated then mostly passes through the exhaust pipe for heat recovery at the water heater 2.

Referring now to Figure 7 of the drawings, there is shown apparatus 201 for heating water according to a further embodiment of the present invention, comprising a combustion element 202, in the embodiment shown a gas burner, a device for absorbing heat 203 and an associated heat exchanger 204 and adapted for the passage of water to be heated, whereby the water is heated indirectly by the combustion element, via the heat exchanger.

The apparatus 201 has a chamber or casing 206 into which tap or mains water inlet piping 207 leads, as does a pipe line 208 for feeding gas to the gas burner via a gas flow controller. There is also water flow sensor 209 on the inlet piping 207 for sensing water flow.

The casing 206 defines a combustion chamber 210 in which the gas burner 202 is located, upstream of the device 203 for absorbing heat in the form of metal plates, in the embodiment copper plates. There is also a further heat absorbing device 203' opposite the first mentioned heat absorbing device 203 and substantially parallel thereto and has an associated heat exchanger 204'. The heat absorbing devices 203, 203' are a high efficiency heat absorption device(s) having metal, e.g. copper plates, which absorbs heat from the first copper plates when they are heated by the gas burner.

There is also a third or yet further heat absorbing device 203" with an associated heat exchanger 204" which also has copper plates downstream and is of the first-mentioned 203 and further 203' heat absorbing devices. The plates of the respective devices 203, 203' and 203" project from and extend at substantially 90° to the respective associated heat exchanger units 204, 204', 204".

In the embodiment, the water inlet piping 207 is bifurcated, part of the water passing to the further heat absorbing device 203' part passing to heat exchanger 204" formed by the third heat absorbing device 203' and part passing to the heat exchanger 204 of the first- mentioned heat absorbing device 203.

There is outlet piping 211 for heated water from the apparatus 201, part of which passes from the heat exchanger 204 of the first-mentioned device 203 and part via piping 212 from the further heat absorbing device 203' and the third heat absorbing device 203", the temperature of the heated outlet water being detected by a heat detector 213.

In use, cold tap or mains water is passed into the apparatus 201 through the inlet piping 207 and is distributed to the three heat exchangers 204, 204', 204" via the respective piping. The water flow sensor 209 is actuated when the water flows through the inlet piping 207, and this in turn actuates an ignition device (not shown) to fire the burner, fed by gas through the gas inlet pipe which gas feed is controlled by the gas flow controller 214. The flames and heat from the burner element 202 directly impacts on the plates 203, 203', 203", which are heated. This array is a high efficiency heat absorber which by conduction heats the tap or mains water passing through the heat exchanger units 204, 204' and 204" so heating the water as it passes through the apparatus 201. At the same time, the hot gas downstream of the gas burner 202 is absorbed by the third heat exchanger 204", so providing efficient utilisation of the heat generated by the gas burner 202. The exhaust fan motor 215 and fan 216 are also actuated when the burner fires, which exhausts unused hot air to ambient whilst maintaining a smooth airflow in the apparatus 201. Hot water is passed from the apparatus 201 via outlet piping 211. The apparatus 201 thus provides for indirect heating of water in pipes 207, as there is no direct heating of the pipes carrying water to be heated.

It will be understood too that the terms "pipes", "piping" used herein are intended to cover tubes and tubing, conduits and heat pipes and any other suitable means for effecting heating of water via the burner and/or exhaust gases.