26-02-2013, 04:54 PM
Thermoelectric generator
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The Seebeck effect is the conversion of temperature differences directly into electricity and is named for the balt-German physicist Thomas Johann Seebeck, who, in 1821 discovered that a compass needle would be deflected by a closed loop formed by two metals joined in two places, with a temperature difference between the junctions. This was because the metals responded differently to the temperature difference, creating a current loop and a magnetic field. Seebeck did not recognize there was an electric current involved, so he called the phenomenon the thermomagnetic effect. Danish physicist Hans Christian Ørsted rectified the mistake and coined the term "thermoelectricity". The voltage created by this effect is of the order of several microvolts per kelvin difference. One such combination, copper-constantan, has a Seebeck coefficient of 41 microvolts per kelvin at room temperature.[2]
pelteir effect
Peltier found that the junctions of dissimilar metals were heated or cooled, depending upon the direction in which an electrical current passed through them. Heat generated by current flowing in one direction was absorbed if the current was reversed. (Note that the effect always involves pairs of junctions, whether the junctions are explicit or just implied in the balance of the circuit.) The Peltier effect is found to be proportional to the first power of the current, not to its square, as is the irreversible generation of heat caused by resistance throughout the circuit.
How it works . . .
TEGs are made from thermoelectric modules which are solid-state integrated circuits that employ three established thermoelectric effects known as the Peltier, Seebeck and Thomson effects. It is the Seebeck effect that is responsible for electrical power generation. Their construction consists of pairs of p-type and n-type semiconductor materials forming a thermocouple. These thermocouples are then connected electrically forming an array of multiple thermocouples (thermopile). They are then sandwiched between two thin ceramic wafers.
When heat and cold are applied, the device then generates electricity.
These thermocouples are then connected electrically in series and/or parallel forming an array of multiple thermocouples (thermopile). When heat and cold are applied this device then generates electricity. Almost any heat source can be used to generate electricity, such as solar heat, ocean heat, geothermal heat, even body heat! In addition the efficiency of any device or machine that generates heat as a by-product can be drastically improved by recovering the energy lost as heat.
Uses
Thermoelectric generators have been in use for many years by NASA to power spacecraft and the oil and gas industry to power remote monitoring stations around the globe. Only in recent years has this technology become available to the general public and TEG Power is at the forefront of this thermoelectric energy revolution. We are the first manufacture to provide practical and affordable thermoelectric generators to the energy conscious consumer.
Soller cell
principle
Light striking a silicon semiconductor causes electrons to flow, creating electricity. Solar power generating systems take advantage of this property to convert sunlight directly into electrical energy.
Sunlight to Electricity
Photovoltaic technology converts sunlight into electricity and is emerging as a major power source due to its numerous environmental and economic benefits and proven reliability.
Enough free sunlight falls on earth to supply our energy needs for years to come.
Environmental Benefits: As PV generates electricity from light, PV produces no air pollution or hazardous waste. It doesn't require liquid or gaseous fuel to be transported or combusted.
Economic and Social Benefits: Sunlight is free and abundant. Photovoltaic systems allows you to generate electricity and store it for use when needed. Photovoltaic contributes to our energy security, as a young technology, it creates jobs and strengthens the economy. It frees us from uncertainties and foreign oil dependence.
This energy source is free, clean and highly reliable. PV systems are long-lasting and require little maintenance. The benefits of Photovoltaics far outweigh the initial cost the systems.
Photovoltaic System
A complete system includes different components that should be selected taking into consideration your individual needs, site location, climate and expectations. In this section we review the components' funtion and several different system types.
Major System Components
The functional and operational requirements will determine
which components the system
will include. It may include major components as; DC-AC power inverter, battery bank, system