GUIDED BY-

B.J. SONANI SIR

PREPARED BY:-

MAYANK H. PAL

5TH SEM MECH.ENGG.

(136120319528)

Topic-:Thermo electric

coolingSub-:Project-1

Gadhiya Sagar K. (136120319506)

Marakana Sanket S. (136120319521)

Mendapara Prince K. (136120319523)

Modi Anuj B. (136120319525)

Pal Mayank H. (136120319528)

Parmar Maulik R. (136120319530)

The thermoelectric cooling is used as renewed

technology, has made an impact in the field of

alternative refrigeration. The common principle

is the presence of coupled electrical and

thermal currents, so that it is possible to use the

effects to generate power from a temperature

differential.

Thermoelectric cooling provides an alternative

solution to the common compressor and

absorber cooler. Thermoelectric coolers are

used especially if small cooling power is

needed (up to 500 W)

Thomas Seebeck in the early 1820’s found that

a voltage difference is generated between the

hot and cold ends when certain materials are

placed in a temperature gradient.

This phenomenon is popularly known as

Seebeck effect.

Depending on the used heat exchangers the

cooling units are distinguished:

air to air

air to fluid

fluid to fluid

direct to air (cooling plate to air)

small size

light in weight

no fluid

independent from the working position

high reliability

exact temperature control

heating by changing the direction of the current

The basic principle behind thermoelectric effect is peltier effect it occurs whenever electric current flows between two dissimilar conductors, depending on the direction of the current flow, the junction of the two conductors will either absorb or release heat.

A thermoelectric material is made of two legs, one of which is ‘n-type’ and contains negatively charged mobile carriers in the form of electrons while the other leg is ‘p-type’ and contains positively charged mobile carriers known as holes. These two legs are connected electrically in series and thermally in parallel.

By connecting 2 wires of different electrically

leading materials at the 2 ends and by applying

additionally a voltage, a current flows, which

transports heat of one junction point to the other.

In the consequence one junction point becomes

cold and the other one warm.

For thermoelectric modules materials are applicable

with a high electrical conductivity and a small thermal

conductivity. Unfortunately good electrical conductors

are also good heat conductors. The best efficiency is

obtained with semi-conductors

Unfortunately good electrical conductors are also

good heat conductors. The best efficiency is obtained

with semi-conductors.

If temperature difference is created between two

different conductors, ‘a’ and ‘b’ having junctions at

M and N, a voltage difference (V) will be created

between M and N appearing between the two ‘b’

segments Therefore, under open-circuit.

On the hot side the net heat from the cold side and

the power required to pump this heat must be

transferred to the environment.

Qh = Pel + Qc

By changing the direction of the current the heat

flow changes too, from the cooling mode into the

heating mode.

THERMAL FLOWS IN A COOLER