is there a reason you're using a mix of copper and aluminum in your construction? Why not stick with just copper instead? yes. firstly copper is very expensive. the two 100x100mm copper plates you see cost me £30. I had 45x 40mm x 5mm pins. which is 1.8meters. + the waste which is at least 45x 30mm (1.3 meters). + the pins that didnt get cut properly. thats alot for 5mm copper rod. also considering about 1/2 will be wasted, i didnt see the point in spending out alot of money when aluminum is more then good enougth for the job and alot lot cheaper. Secondly, copper is a metal that is very difficult to machine, it wouldnt have been able to use the computer controled lathe on the pins in the same way i did for the aluminum. and i very much doubt i would have been able to source box shaped copper for the top heatsink. hope this explains it all for you. anymore questions feel free to ask.
I remember something about how 2 differing metals can corrode each other...is this a factor in Alu/Copper constructions?
The two metals will only corode when a conductive liquid is present. The two different batteries plus liquid make a crude battery that corodes.
Great project, I think I'm going to have to make something similar for my dorm room . Can't wait to see it finished and how it performs.
Assembly of the components I have manufactured so far The first stage of the assembly process began with gluing the insulation for the Peltier to the bottom surface of the hot/cold plate I first did a final clean of the area in contact with the Peltier then spread some heat sink compound evenly onto the copper surface to allow for good heat transfer. The Peltier was then placed in position, I then spread some heat sink compound onto the other surface of the Peltier, and then glue the other side of the insulation onto the copper heat sink sandwiching the Peltier in-between the copper hot/cold plate and the heat sink. I performed a quick test by just hooking up the Peltier to a power supply. I found that the Peltier was able to both heat and cool the hot/cold plate. This means that I have good thermal conduction between the Peltier and the copper plates either side of it. I also found that the heatsink pins warmed up, which means they are in good contact with the copper plate. Discuss
Small update on the general building front. In the process of sorting out the electronics design/prototyping ready for upload. and sorting out a few screenies from my CAD work.
What kind of base are you planning on building so that the fan can pull air through? Something like the cut u alu might look cool on the bottom too.
Do you know how many watt do we need at least to keep a glass of beer on a nice cold temperature or cool it down when it is at room temperature?
"What kind of base are you planning on building so that the fan can pull air through?" have not totaly decided yet. but i have a few cool ideas "Do you know how many watt do we need at least to keep a glass of beer on a nice cold temperature or cool it down when it is at room temperature?" yes. i have some calculations ect, that i will put up in the general design section asap, possibly tonight, however atm im away from my main comp so it mite have to wait till tomorrow. Edit- the awnser to your question is now up
Electronics Design Circuit Diagram- Hand drawn only so far, when I get time I will redraw it on the comp. Bigger Diagram Note: this is a slightly old diagram, the 20K resistor is now a 6k8 and the 12k is now a 4k7. explanation behind this will be in the electronics prototyping section. Wireing Diagram- Bigger Diagram Circuit Explanation- There is an output from the comparator if the + voltage input is larger then the – voltage input. When cooling- If the input voltage from the temperature sensing IC (LM335A) is higher then the voltage set by the user (variable resistor) then the Comparitor IC (LM393) will allow power to the Transistor (IRFR024N) and so the Peltier will be switched on and will cool down the drink. This then lowers the voltage input into the comparator (LM393) by the temperature sensing IC (LM335A). Once the voltage input by the IC (LM335A) is lower then that input set by the user (variable resistor) Comparitor IC (LM393) will not give an output and the transistor (IRFR024N) will switch off the Peltier. This process will keep on happening as the temperature varies to keep the drink at the temperature selected buy the user. When Heating- The inputs will be reversed by the use of the hot/cold switch so that the IC (LM335A) goes to the – input on the comparator (LM393) and the voltage set by the user (variable resistor) goes to the + input. This means that when the IC (LM335A) heats up and the voltage increases to the point at which it is more than the voltage set by the user (variable resistor) the Peltier will switch off. So pretty much it is the same as cooling accept with the inputs to the comparator reversed. Random Info- When switching between hot and cold two switches are actuly made, the temperature control stuffs is switched and the polarity of the pelteir is switched. This system also allows for energy saving since the Peltier will not be running when it does not need to be. The tempearture sensing IC outputs a voltage directly related to the temperature in degrees kelvin. The circuit is also build to be as precise as possible, I should hopefully allow me to set a temperature to maintain with an accuracy of +or- 1 degrees centigrade. This will be achived through calibration which i will explain a bit later on in the project. The circuit has also been designed to be fairly small in the amount of space it takes up, which allows me to keep the size of the case it is going to be housed in small. Parts list with cost- Resistors 2k 10k 27k 27k 3k9 3k9 4k7 5k1 5k6 6k8 10M Total = £0.77 Variable resistor 1k = £0.99 Preset 2k2 = £0.99 Main componets LM335A = £1.49 LM393 = £0.49 1N4148 = £0.08 IRFR024N = £1.77 LM329 = £2.00 Switches 4 pole double throw switch = £2.99 Main on / off switch = £1.49 LEDs to indicate heating/cooling mode. Red LED = £0.10 Blue LED = £1.78 Other bits 60W Power Supply = £29.99 Lots of wire = n/a Discuss
3 things: 1) Isnt it a bit overkill for a 30w peltier, why not pick up a 320watt peltier and get some really cold drinks, i suspect that heatsink arrangement will support it! (http://cgi.ebay.co.uk/320Watt-Pelti...ryZ42001QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) for instance 2) how does air get into the fan? (i guess it isnt finished yet...) 3) That electronics component list has some VERY pricy items on it... (rapid sell 100 resistors for £0.60 - alladmit all of the same value but still... (they do a assortment pack) check them out... good luck, looks cool!
you realy think one 80mm fan and that heatsink would be able to effectivly disapate 320Watt of energy? that would most definatly require a watercooled solution. do you have any idea how big and costly a 320watt standalone power supply would be for that? considering that the 60watt supply i got cost me £30. the entire temperature control circitry would have to be changed to deal with a HUGE 26amps. i would need large gauge wires to prevent resistance and heating. also why would I need such a pelt? if i were to use it to heat the water it would have no problem boiling it within a couple of minutes, a pelt of that size would be totaly over kill. thats correct its not finnished yet, it will be raised from the ground so that there will be efficant air flow. I fail to see what is VERY pricy as you put it. I got 11 single variying sizes of resistors for £0.77 and i didnt have to pay the postage costs that rapid charges
Definately a cool project, soemthing that you would expect to see on somewhere like iwantoneofthose or boysstuff. Any plans to market it?
bit of an update, got the electroics explantion up. my intention was to make it understandable to people with very little electroics knowledge so if you feel like building your own you can, hopefully I have succeded. If not please offer suggestions for changes. anyone who does have electroics knowledge can just ignore it, because the circuit diagram should tell you all you need to know.
If there isn't a patent on this... do it! I'm sure some far eastern manufacturer of useless USB peripherals would love to make something like this and flog it around the world... and you should get a little bonus every time one of these sells! Think it over, anything it seems is marketable and sell-able these days (take a look at the kid who sells pixels for $1 each and is up £40,000 so far )... and i'm sure you're beer chiller / tea warmer would be an ideal hit. As an engineer (by education; as profession, I value the business of money earning more! ) i'm finding this very interesting,.. keep up the good work! :thumbs:
I want one! I live in las vegas and it would actually be usefull here. Anyone that tries to have a cold drink in 125 degree heat knows what Im talking about!
