In this i had used the heating effect of peltier .. many of us have knowledge about the electronic device peltier. it is basically made by the P-N juctions inside which makes the temprature difference when electricity is passed through it.
i had used TEC1-12706 which have 127 PN couples in it and can withstand till 6A current..
configuration of 12706 peltier are used nicely to produce freezing point temprature becoz of temprature difference it produce .
sorry for nazi english ...
Step 1: Required
There the required things as mention below:-
1. TEC1-12706 peltier: if u have other type of peltier that can be used.
2. Power supply: I used old computer power supply which works really nice for my peltier heater.
power supply able to give 12volts with nearly 5amps.
3. Aluminium heatsink: Prefer to take a more fins heatsink and gaps between these are enough for air flow.
4. DC motor: use any dvd player motor becoz they are silent and able to work for long time
5. Plan plastic sheet
6. pvc L shape bend
7. connecting wires
For fan speed controller:
9. resistance - 100ohms, 1kohm pot
10. capacitors- 0.1uf, 10v 100uf
Step 2: Fan Blades
Take a plastic little sheet . as i got from oil bottle .
Using compass make the circle of 8mm and another big circle equal to the pvc pipe mouth radius.
Now make the lines on sheet with marker. I made 16 fins. so draw lines and cut them by blade or scissor.
now just twist each blade in one direction so they are slightly twisted ..
shown in figure that how the air will goes out.
u can also get another kind of blades on this instructable
Step 3: Attach DC Motor
Take your breadboard wires and remove those insulator by this u will get inner thick aluminium wire and now cut that wire into pieces of 15cm each .
now tie each wire on dc motor and make them enough tight so that they will not come out.
tie another wire at angle of 120degree and third pair on 240degree. i used the pair wire at each angle so the vibration will b less and useful in next post.
Apply epoxy on wires so that. they will not move .. it takes some time so just wait to get it hard enough.
Now attach the fan blade on motor. add some epoxy so blade not removed in future.
by this your fan is just ready.
Step 4: PVC Bend
take the pvc bend and make hole pair on plain surface at each 120degree.
now put those aluminium wire to pass through each holes and fan must b inside tube.
fix the motor such that its blade not touching inner surface and wire are tighten enough..
Step 5: Heatsink
Take heatsink and place in on the other side of tube .. it must be like that so the all air only pass through fins.
Put heatsink on pvc tube and mark the area and remove all pvc part between those mark so that heatsink can be setted there .. i had removed pvc by solder iron.
make another hole on side as in 6 of pvc and make the wire band to heatsink on both side to make little permanent system.
Step 6: Peltier
To attach the pelteir add some thermal flux on peltier and put it on heatsink .. becoz improper use of thermal paste can cause of peltier heating of low heatsink heating.
Take out the wire by tube hole which made in pvc tube.
second pic is about peltier that how it give temprature difference in different conditions
Step 7: Final Packing
Becoz the air only to be pass through heatsink fins so there no leakage in air pass..
heatsink not coverd the whole pvc so remaining area can be coverd by mold of that size or as i cover by tape .
also dont forget to cover over the fin area by this all air comes out after touching fins. This makes heating of air more efficient.
Step 8: Air Flow Control
Air flow control is done by regulating the speed of dc motor -> which is done by regulating dc voltage.
to regulate dc voltage i used LM317 ic which easily regulate the voltage over 3-10volts as mentioned above circuit.
there input can be12v output from computer supply .. transformer can not be used in peltier becoz they cant give enough current for peltier.
Step 9: Power Supply
i had used old computer power supply by which i get enough power to run whole system ..
to start the supply short the wires of green and black.
by connecting the power system and starting the system than in opposite side temprature is gone below freezing point so there ice crystal are started forming.
after use of 7 hours there a bulk of ice crystal is made.
this system uses 2.85amps at 12volts input supply.
if u want more heat in heatsink than add another peltier with thats hot side attached to the cold side of already placed peltier now connect new peltier by 5volt supply becoz if connected by 12v than it produce too much heat which can not be handled by heatsink ...
for first time use check the heatsink temprature after every 10-15 min that is it really heated too much..
just make and enjoy yourself in this icy winter.
Step 10: Control Temprature
if u used two peltier and heat heat much enough so that warm wind can also be got after switching off peltier supply than astable multivibrator can be used to control switching power in peltier. ..
i also tested that i get warm breeze till 1 minute of switching off peltier. ..
genereally heatsink got heated with in 1 minute ...
so my method is to use multivibrator in circuit. input supply 5volt is given by power supply box and output is connected to a relay which control the on and off supply of peltier.
for 65sec on and 65sec off
if u using one peltier by which warm breeze comes only for few times than u must attach fan supply to the relay output.. becoz of this when fan is off then heatsink didnt face cold air and it gets hot .. when it got enough hot than again fan start and hot air comes out and heatsink temprature again goes down..this process works again and again..
more details to adjust multivibrator