The need at the moment is eco-friendly Air Conditioners. The present Air Conditioning System produces cooling effect by using Chloro Fluro Carbons like Freon, Ammonia, etc., Which damages the environment. We can overcome the existing Air Conditioning System by modifying it to protect the environment. By using Thermoelectric modules (Peltier Modules) Air Conditioners can be made. These Air conditioners can be used summer as well as in winter. These Thermoelectric modules are completely eco-friendly system. These type of air conditioners have wide range of applications.
The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa.
A thermoelectric device creates a difference in temperature on each side when a voltage is applied (known as the Peltier effect) and vice versa.
WHY THERMOELECTRIC MODULES ??
Now the thermoelectric modules are used in places like medical application, temperature preference testing machine, theme park exhibit, laboratory and research purpose. But we here applied in air conditioning system. Because in these type of crystals heating and cooling is produced simultaneously and also it consumes only less amount of electrical energy.
When a current is made to flow through the circuit, heat is evolved at one junction and absorbed at the another junction. This is known as Peltier effect.
A Thermoelectric module is a device composed of thermoelectric couples (n and p-type semiconductor legs) that are connected electrically in series, in parallel thermally and, fixed by soldering, sandwiched between two ceramic plates. The latter form the hot and cold thermoelectric cooler (TEC) sides. Thermoelectric modules are also known as Peltier modules.
COMMERCIAL PELTIER MODULE
WORKING OF THERMOELECTRIC MODULE
By applying a low-voltage, high-current, DC power source, heat will be moved in the direction of the current (+ to –). The heat is pumped from one side of the module to the other, so that one face will be cold while the opposite face will be heated, and the effect is reversible.
EFFICIENCY OF A THERMOELECTRIC MODULE
Technically, the word efficiency relates to the ratio of the amount of work one gets out of a machine to the amount of power input. In heat pumping applications, this term is rarely used because it is possible to remove more heat than the amount of power input it takes to move that heat. For thermoelectric modules, it is standard to use the term “coefficient of performance” rather than “efficiency.” The coefficient of performance (COP) is the amount of heat pumped divided by the amount of supplied electrical power.
The COP depends on the heat load, input power, and the required temperature differential. Typically, the COP is between 0.3 and 0.7 for single-stage applications. However, COPs greater than 1.0 can be achieved especially when the module is pumping against a positive temperature difference (that is, when the module is removing heat from an object that is warmer than the ambient). The figure below shows a normalized graph of COP versus I/Imax (the ratio of input current to the module’s Imax specification). Each line corresponds with a constant DT/DTmax (the ratio of the required temperature difference to the module’s DTmax specification).
ADVANTAGES OF A THERMOELECTRIC UNIT OVER A COMPRESSOR
Thermoelectric modules have no moving parts and do not require the use of chlorofluorocarbons. Therefore they are safe for the environment, inherently reliable, and virtually maintenance free. They can be operated in any orientation and are ideal for cooling devices that might be sensitive to mechanical vibration. Their compact size also makes them ideal for applications that are size or weight limited where even the smallest compressor would have excess capacity. Their ability to heat and cool by a simple reversal of current flow is useful for applications where both heating and cooling is necessary or where precise temperature control is critical.
- This type air conditioner is completely eco friendly.
- This air conditioner can be used as both summer air conditioner cooler) and winter air conditioner (heater)
- It consumes lesser voltage then conventional air conditioner.
- Thermoelectric module have a life expectancy of 2,00,000 hours.
- It can be used even to cool the internal air the room.
- As the number of stages in the thermoelectric module increases, the achievable temperature difference also increases. Unfortunately, the heat pumping capacity decreases.
- The initial investment is quietly high when compared with the conventional air conditioners.
- The efficiency is slightly lower than the normal air conditioners.
- Applied for cooling rooms.
- Used as room heaters
- It is used to make cooled car seat.
- Used as coolers in CPU and other electronic appliances.
- Can be used for refrigeration purpose.
It consumes only a little amount of electrical energy and also completely eco- friendly. A single machine can be used as both cooler and heater and has many other applications like car seat coolers, CPU coolers, etc.,