DIY Chiller/heater - Peltier device

Has anyone experimented with peltier devices to make their own chiller? I am thinking of giving it a try. My plan is to use a brand new aluminum transmission oil cooler, this will provide a great dealt of conducting surface for cooling, along with a 12 inch 12v fan for the cooling side, a computer heatsink and fan for the other side and sandwiched in between two 136 watt 12v Peltier devices. I will need a 12v 30 amp power source, a 12 volt temperature controller that triggers two devices one for cooling and one for heating, and finally a couple of 12v 30 amp relays. I believe I can do this for under 150. and get all the parts from ebay. They have a Peltier temperature controller that works with 9amps that would have been nice to use however, my project will use at least 18 amps so I am forced use the relays to reverse the polarity to switch between heating and cooling. I will update this post with the results of this project.

Okay I have ordered the following parts. it will probably take a few weeks for it all to come in::

Universal Aluminum Remote Transmission Oil Cooler,12-3/4" x 7-1/2" x 3/4" 26.98


2x-136-8W-12V-9A-TEC1-12709-TEC-Thermoelectric-Cooler-Peltier 10.71

7" DIAMETER 12V ELECTRIC POWER RADIATOR COOLING FAN 19.98

AVD Brushless DC cooling fan N5010B2 12V 0.012A 3-wire w/ molex and Heat Sink
10.90
100-350L/H DC 12V 6W Micro Pump Motor for PC Water Cooling System 3pin Connector 5.55

30g ST801 CPU GPU LED Heatsink Silver Thermal Conductive Silicon Grease Paste
4.27
Still working on the power supply, I figure an ATX 20AMP 12v rails I figure this will be around 11.00 shipped, all these prices include shipping. With these parts I have enough to test the capabilities before investing another 30 or so to set up a temperature controller.

I have begun assembling the device, I have a few things to work out like should the 12v fan be blowing on the radiator and the peltier heat sink, or just the heat sink, and keep the radiator insulated? I will find the answer to this through some basic experimentation, first I have hooked up the pump and radiator, see picture below. The tank I am using is a 75 gallon filled 3/4 of the way. The normal average room temperature of the tank has been 59.6. With the addition of just the radiator and pump it is 55.9. The small computer cooling pump creates a very slow trickle through the radiator, if the end results are not as desired I will have to test increasing the flow rate with a stronger pump. I will test the following over the next couple of days:

1. Temperature drop with radiator and 12v Fan
2. addition of Peltier devices, with fan blowing through both radiator and heatsink
3. With fan blowing only through peltier device heat sink, and radiator insulated,

I created a contact point for the peltier devices on the radiator by filling a square shaped area with JB Welding epoxy, Since JB is a steel based product I expect it to be a good conductor of heat, also it has high temperature rating.

Interesting results from the fan, the temperature in the tank went up to 60.3., not what I expected. It appears that the fan and radiator do indeed facilitate the transfer of heat, but not in the direction I expected. I am assuming this is because the room temperature is 65 and is higher than the water in the radiator, thus transferring heat into the aluminum coil rather than removing it. I verified this by placing the temperature sensor directly inside the outtake tube and found it was a few degrees warmer than the tank at 60.7. So that answers all my questions then, I will need to have the fan directed through the peltiers heatsink and the radiator insulated only having contact with the peltier device, contact with room temperature air will only increase the heat in the tank.

After running a few more tests I have discovered a few things, first the radiator is a waste. At these low temperatures it really doesn't do anything. Since it designed for higher temps I am guessing it is just too thick to be useful. I am switching to using CPU water cooling blocks which I have on order. I discovered that the 12v rating on these peltier devices is BS! they can take the voltage but will not produce a cold side! I have been told that it will work if you can remove the heat from the hot side fast enough, well, it becomes a moot point because if you could do that you would already have an efficient chiller. Luckily with the computer power supply I have several voltages to choose from, these peltier devices will produce a cold side at 6-9 volts. When the new cooling blocks come in I will post my final results.