DESCRIPTION The present invention relates to an improved improved heating system.

Conventionally, buildings are heated by means of radiators that are provided at intervals throughout the building. A main hot water pipe is heated by a boiler and the heated water is then delivered via pipes to the individual radiators. The water flows into subsidiary pipes provided in the radiator that results in the radiator heating up and releasing heat to the surroundings by means of radiation, convection and radiation. This requires a large amount of hot water to be pumped around a building and each individual radiator. Additionally, due to the radiators having to be in fluid communication with the main hot water pipe to receive water therefrom, it is difficult to alter the positioning of a radiator since the pipework to the radiator has to be altered.

Furthermore, radiators normally include mechanical temperature limiters to allow control of the temperature of an individual radiator and to ensure that the temperature of the radiator does not become too high which could cause a boil up within the system. However, such parts may break down and thus remove any control over the temperature of the system. This

is particularly undesirable with domestic radiators that may be contacted by small children. The incorporation of mechanical temperature delimiters into a radiator also adds to the cost thereof.

It is an object of the present invention to provide an improved heating system that aims to overcome, or at least alleviate, the abovementioned drawbacks.

Accordingly, the present invention provides a heating system comprising a self-contained partially evacuated unit containing an amount of working fluid and at least one conduit discrete from said unit for the transportation of a heat transfer medium wherein contacting the unit with a surface of the conduit effects heating of the working fluid, wherein the temperature of the unit is controlled by having a predetermined ratio of working fluid volume to the internal volume of the unit at a given pressure and heat input.

Preferably, the unit is rectangular, for example, being comprised of two parallel spaced apart sheets that are joined together to provide an internal cavity. More preferably, the heating system is arranged such that the long side of the rectangular unit is in contact with the conduit that transports the heat transfer medium. The short side of the rectangular unit is preferably between a quarter and half the length of the long side of the rectangular unit, more preferably one third of the length. It is preferable for the base of the unit to be concave in profile such that it can stand on the

conduit. Preferably, the base of the unit contacts 45-50% of the circumference of the conduit. More preferably, the unit is provided with convecting fins.

The heat transfer medium flowing through the conduit is preferably water. The conduit is preferably connected to the conventional mains water system.

It is to be appreciated that the unit should be provided with means for evacuation thereof and for introduction of the working fluid.

Preferably, the working fluid is water. The volume of working fluid in the unit is provided such that, at a given unit volume, heat input from the heat transfer medium and vacuum, a desired maximum temperature can be achieved thereby enabling the unit to operate without a mechanical temperature controller, such as a thermostat. It is preferable to provide a maximum temperature in the range 55°C to 83°C using a volume of 13 to 32% working fluid relative to the volume of the cavity depending upon the actual maximum temperature desired. This is for a vacuum of between 29.62 inches Hg (100304.87 Nm-2) to 29.82 inches Hg (100982.14 Nm-2) and having a heat transfer medium at 80-83°C. If a maximum temperature of 550C to 65°C is desired, more preferably 59°C to 63°C, to provide a sufficiently warm radiator to heat up the surroundings but having a surface temperature that is not too hot to touch, a volume of 13 to 17%, more preferably 15% working fluid (such as water) relative to the volume of cavity

of the unit provides an effective temperature limiter within the system to provide such a maximum temperature.

If a higher maximum temperature is required, for example in the range 78-83°C, a volume of 25 to 32%, more preferably 28-29% working fluid relative to the volume of the internal cavity is provided in the unit.

It is to be appreciated that the amount of working fluid in the unit will need to be slightly greater for a unit that is provided with convecting fins than for one that is not.

Preferably, the heating system is provided with means whereby contact between the unit and the conduit can be broken. For example, the unit may be sprung mounted with respect to the conduit, the unit having a threaded screw at a point along the base thereof that may be turned to slightly lift the unit causing it to break contact with the conduit.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made by way of example only to the accompanying drawings in which: Figure 1 is a schematic plan view of a heat transfer system according to one embodiment of the present invention; and Figure 2 is a side view illustrating the contact between the unit and heat transfer pipe of the heat transfer system shown in Figure 1.

Referring to the accompanying drawings, a radiator panel according to one embodiment of the present invention is illustrated. The panel

comprises a partially evacuated self-contained rectangular unit 2 of a suitable conductive material, such as mild steel. The unit has means, such as a valve (not shown) for evacuating its internal cavity and for introducing a small amount of working fluid, such as water, into the cavity. The unit is supported on a heat transfer pipe 6 that transfers a heated medium such as water W around a building, being connected by suitable means to the standard domestic heating system. The base of the unit has a concave profile 10 which sits on the heat transfer pipe 6. Only 50% of the heat transfer pipe is in contact with the base of the unit.

The radiator unit is provided with a non-mechanical temperature limiter. For example, for a radiator unit that is 900mm x 500mm to provide a cubic inner volume when holding a dense medium, such as water, of 2.6 litres and having a vacuum of between 29.62 inches Hg (100304.87 Nm-2) and 29.82 inches Hg (100982.14 Nm-2), a volume of 400ml 10% working fluid is required in the cavity of the unit to achieve a maximum surface temperature of between 59 to 63°C when water that flows through the pipe from the boiler is reaching a temperature of 80 to 83°C. Thus, it can be seen that the volume of working fluid acts as a temperature delimiter since the radiator unit does not achieve the temperature of the heat transfer pipe. If the same radiator is provided with convecting fins, a slightly greater volume (440ml) of working fluid should be provided in the unit to provide the same maximum temperature.

The provision of a radiator that has an internal cavity that is twice- that of the example above requires 800ml of working fluid within the cavity to provide the same maximum temperature, subject to the vacuum and energy input into the system being the same.

In an alternative embodiment, a higher maximum surface temperature is achieved by providing a larger quantity of working fluid within the cavity of the unit. The rectangular radiator units sits on a heat transfer pipe and the radiator has a height that is approximately one third the length of the radiator that is in contact with the heat transfer pipe. The radiator has an internal cavity of 3.150 litres and 900ml 10% of working fluid is provided at a vacuum of 29.82 inches Hg (100982. 14Nm-2). The temperature of the heat transfer medium heated by a boiler is around 84°C.

This higher volume of a working fluid provides a maximum surface temperature of 78-83°C.

The arrangement of a rectangular radiator unit that contacts a heat transfer pipe ensures that a highly effective temperature delimiter can be achieved by means of the volume of working fluid contained within the internal cavity.

The radiator of the present invention provides a simple, lightweight and cheap radiator that would be affordable to the general public and makes efficient use of energy since it does not require water to be transported around convoluted pipes contained in the radiator and it does

not allow a radiator to be heated such that the surface thereof is excessively hot which is both hazardous and wasteful of energy. The intrinsic temperature delimiter provided by using only a particular amount of working fluid within the unit such that the vapourization of the fluid acts as a temperature limiter also avoids the need to include a mechanical limiter within the unit.