Classical hot water equipment is based upon an electrical or gas source. The technology used is the heating resistance submerged in water, or the heat transfer or the heating flame on a radiator with a certain water flow. These technologies are classical and the energy transfer operates from the heating element (resistance, wall transfer or radiator) to the volume of water. For specific applications one can use infra-red radiation.
It is well known that water strongly absorbs microwaves [1], [2], [3] resulting in a temperature increase. By using a coil transparent to the microwaves, these will be able to heat water in an instantaneous manner.
The advantage of this system is to heat the water alone, in the volume and from a distance. The microwave activated hot water equipment will be valid for the following market segments:
Hot water equipment for domestic, office and camping.
Space heating by autonomous radiator.
The hot water flow, as well as the power equipment requirement, allows one to differentiate quantitatively between these segments. As an exemple, a power of 2 KW permits a temperature increase of 30 ° C for a flow of water of 1 L / mn .
This device is particularly well suited for the volumetric heating of various liquids in an instantaneous manner. By adding a circulator it is possible to use this device as a hot water equipment with storage.
The principle can be generalized to the hot-liquid equipment market applied to liquids in restaurants, to chemical production and to medical and chemical processes.
One can propose a modular heating system which is able to receive the microwaves with a wave guide coupled to a magnetron, or to a coaxial cable for specific applications.This modular device is then applied to the liquid-heating of water, edible, chemical and medical products. The nature of the pipe material is adapted both to the liquid and the microwave radiation.
For reasons of economy and conception, it is more advantageous to manufacture a modular system of 1 KW rather than 2, 4 or 6 KW ; thus added in series or in parallel these devices will increase the temperature or the flow of the liquid. For specific industrial applications these devices will be able to be totally autonomous and thus to constitute operational heating circuits.