Peltier, Heat Sink and Pump Test

Peltier, Heat Sink and Pump Test

Date:11.2.17
Location: Logan HS
Time: 4:15 PM -6:30 PM
Goal: Connect hoses to test pump, peltiers and temperature difference in water with the peltiers.
Students: Andy, Court and Ben

We wanted to begin connecting the peltier, heat sink, hoses, cooling blocks together to test the system. Overall we wanted to see if we could cool the water coming from a source bucket through the cooling blocks and then back into a different bucket.

Problems occurred right away. The second bucket had a leak in it and when we wired our potentiometer to the pump it worked varying the pump speed for a while and then "smoked" the potentiometer.  We will have to look up the wiring configuration again and the ratings on the potentiometer.  Additionally, we could not get the cooling block to cool down the water significantly but we think we have determined the problem which is in our flow rate. For this test we wanted to keep a constant flow rate and not vary it. If we slow down the flow rate we can hopefully improve the cooling properties.

We also started with a warm water temp (about 82 degrees F.) to simulate the water temp in the Indian Ocean. We can improve our delta temp. if we use cold water from a water tap.

The good news is the small pump works well...in fact too well. It really pumps out the water (4 ft. up in the air) so the flow rate will need to be controlled because it was much to fast. We could not get the blocks to cool fast enough. We will  also need to research a device which will allow us to monitor the flow rate of the water.  the Pentium 2 heat sink we purchased on e-Bay works great at keeping the peltiers from overheating. Our tests indicate we can get the peltiers down to 43 degrees F using only 1.72 amps. I think we can get it lower  by adding another peltier to the cooling block (3 instead of 2) with time and experimentation.

Base line test measurements:
Starting water temp = 85 degrees F. (to simulate the Indian Ocean temp)
Starting temp of cooling block -= 75 degrees F.

The test data below indicate to what degree we can cool the water cooling block without water running through it. Note that we seem to stabilize at around 44 degrees F.
Initial Temp of Cooling Block- 71.5 degrees F
Peltiers amperage draw - 1.72 A
Time and Degrees F.
1 min = 53.8
2 min. 49.5
3 min = 46.7
4 min = 46.8
5 min. = 46.0
6 min. = 44.5
7 min. = 44.6
8 min. = 43.8

Questions that need to be answered:
1. If we increase current to the peltiers will it lower the cooling temp?
2. How do we vary the water flow rate?
3. How do we monitor the water flow rate?
4. Can we insulate the plastic tubing to prevent heat/cooling loss?
5. Would a different (flatter) cooling block that disperses the water out more make a difference?
6. Three peltiers vs two on the cooling block?
7. Does hooking the peltiers in series vs parallel make a difference?

Short video on how we conducted our tests. This was our first try at it so our testing procedures will improve with experimentation.

Image of our blue water cooling block and black heat sink with the white peltiers sandwiched in between. The hot side of the peltiers face the heat sink.

Andy is making great progress with the thermistors , LCD and Arduino program.

Andy at work on the temperature monitoring program.

Ben heat shrinking some wires.

Court soldering some extension wires on the peltiers.

Snap shot of how low we can get the peltiers without cooling block attached. The peltiers were hooked in series and drawing under 2 amps.

We created a chart to keep track of our temp data.