4. Description
In existing heating devices many types of heat generation devices like resistive heating, RF heating, microwave heating and other semiconductor material heating along with fuels like coal, gas etc. are used. But while providing indirect heating from the source depending on the requirement various metal plates with varied thermal conductivity are employed. There is necessity for developing a coating over metal surfaces to absorb as well as transmit heat in an effective manner without losing heat in the process to the surroundings. Selective coating of Nano materials enables optimizing the efficiency of the systems.
Background of invention
A heating system is a mechanism for maintaining temperatures at an acceptable level; by using thermal energy within a home, office, or other dwelling. Often part of an HVAC (heating, ventilation, air conditioning) system. A heating system may be a central heating system or distributed.
Induction heating is a non-contact method of heating a conductive body by utilising a strong magnetic field. Supply (mains) frequency 50 Hz or 60 Hz induction heaters incorporate a coil directly fed from the electricity supply, typically for lower power industrial applications where lower surface temperatures are required. Some specialist induction heaters operate at 400 Hz, the Aerospace power frequency.
In the early days of induction heating, the motor-generator was used extensively for the production of MF power up to 10 kHz. While it is possible to generate multiples of the supply frequency such as 150 Hz using a standard induction motor driving an AC generator, there are limitations. This type of generator featured rotor mounted windings which limited the peripheral speed of the rotor due to the centrifugal forces on these windings. This had the effect of limiting the diameter of the machine and therefore its power and the number of poles which can be physically accommodated, which in turn limits the maximum operating frequency.
In the early 1970s the advent of solid state switching technology saw a shift from the traditional methods of induction heating power generation. Initially this was limited to the use of thyristors for generating the 'MF range of frequencies using discrete electronic control systems.
Limits to the flexibility of the process arise from the need to produce dedicated inductors for many applications. This is quite expensive and requires the marshalling of high current densities in small copper inductors, which can require specialized engineering