Conventional cooling methods like Mechanical Vapour Compression Cycle uses refrigerants which contains CFC which depletes ozone. Looking forward for a green and cost efficient cooling source, the ‘Peltier-Seebeck’ effect paves way for a new technology called ‘Thermoelectrics’. When voltage is applied to Peltier element, it creates a temperature difference i.e one side becomes cold and the other becomes hot.
The main aim of this research is to use this cooling/heating source to replace conventional air conditioning techniques. While hot and humid Indian weather causes condensation on the cooling surface and as also humidity has to be controlled for human comfort, air has to be dehumidified before cooling it. Desiccant materials like activated charcoal, silica gel etc. has the ability to absorb moisture from air and its regeneration is done by simply passing hot air. Fortunately, the rejected heat on the other side of peltier element can be used as heating source for this process. Peltier element consumes only less electricity and stacking the elements gives improved results. Interestingly, peltier element can generate voltage when we create a temperature difference which can be provided by solar heat energy.
By using these concepts a prototype was created which uses 'Peltier Element' for cooling/heating and 'Dessicant Rotor' is used for humidity control. The fresh air from outside is pumped inside by a centrifugal blower after passing through a filter.
This air passes through the bottom half portion of the desiccant rotor. The moisture is absorbed by the desiccant from this supply air. Dehumidified air then flows through the cold side fins of the Peltier element. Here heat transfer takes place and the temperature of the supply air is reduced. This fresh cool and dehumidified air flows inside the space to be cooled.
Now hot air from the inner space of the room is pumped inside by a centrifugal blower. This air flows through the hot side fins of the Peltier element. Thus the air becomes hot and its temperature increases. The hot air then passes through the top half portion of the desiccant rotor. Thus it wades away the moisture absorbed by the desiccant.This hot and humid air is exhausted outside. This instrument thus can be used as a cooler, heater, dehumidifier and ultimately an electric generator.