The thermoelectric effect is the direct conversion of temperature difference to electric voltage. Thermoelectric generator is nonmoving electrical energy production device that convert heat in to electricity. Since there is a temperature difference between the both ends of thermoelectric generators, so there will be a flow of electrons from hotter end towards the colder end. This is basic phenomenon for conduction of heat from one body to another body. This is the way from which the heat is transfers. The difference of temperature between the hotter and colder sides of thermoelectric generator is directly proportional to the electric voltage produced via see beck effect. Thermoelectric generator module comprises p-type
and n-type semiconductor materials sandwiched
between the hot and cold plate at hot (Th) and cold
Temperature (Tc) Reservoir and connected electrically in series and thermally in parallel. Thermoelectric generator internal effect can be seen by figure
Thermoelectric generator convert heat difference Q in to electrical power P with the efficiency η
The amount of heat (Q) that passed through the hotter side of thermoelectric module depends totally on the type of material used between the hotter and colder side of thermoelectric generator. The thermoelectric generator uses the heat and rest of heat, that can be called as waste heat is passed to the colder side of the thermoelectric module. This side of the thermoelectric module needs to be cooled in order to achieve better efficiency. The efficiency of Thermoelectric generator depends on the temperature difference (∆T = Th – Tc) between the hotter and colder side of the thermoelectric generator. The efficiency of thermoelectric generator defined.
Zinc Metal Sheet.
Zinc metal sheet is a corrosion resistant material that is non-sparking and mostly employed in open-air applications. Zinc is an environment friendly metal. This is because it can be recycled easily through various different processes. It can be easily molded into any form. It has no impact on the environment. In this project we use zinc metal sheet in the construction of solar heater and also as module supporting tray. Figure 3.4 shows us the Zinc metal sheet.
Where it is placed above the Aluminum panel. Solar heater will use 2 main phenomenon’s for getting more temperature then the outer atmosphere. One is greenhouse effect and other is black body radiations. We have made the inner surface of the solar heater black so that it can absorb more radiations. The radiations coming from the sunlight can be made to store by solar heater. The material used for the preparation of Solar heater is Zinc Metal sheet having a thermal conductivity of 116 W·m−1·K−1 .A glass sheet is used and Zinc metal sheet plate is made black in order to absorb more radiation and make the zinc Metal sheet hot in less time. In order to make this solar heater working efficiently we need to insulate the heat so that it may not flow to the outer atmosphere. Polystyrene have a very low thermal conductivity (0.033 W·m−1·K−1 ) and therefore is a very good insulator. Basically this technique is inspired by greenhouse effect and black body to maintain temperature which is needed for operation. Using this Technique We achieved our desired temperatures from this technique. 84oC temperature was achieved on the inner surface of solar heater and 75oC on the outer surface of the solar heater. This 75oC which is going to touch the hotter side of TEG module is enough to give us good results.
Numbers of readings were taken and some of those
are concluded in graph. Results show that as much
difference between hotter and cooler side is provided
the more we get the output. In other words we say that output is directly proportional to the temperature difference applied, but this behavior is in proportion to an extent.