Testing the Desalination Machine

Testing the Desalination Machine

Date: 5.31.18 and 6.1.18
Location: Logan HS
Students: Entire DE Class
Goal: Test Desalination Machine to get a clean water output.
Time: 1.5 hours

Today was the big day! We wanted to run the DM with our new battery and see if we could get some water output.

We started up the DM and ran the fan and pumps at a very low speed for about 30 min. Everything worked well, but we were not seeing a very large temp difference in the tanks. This was disappointing as our temp probes indicated that we were heating and cooling in the right locations. We increased the fan speed to about 75% and that is when we saw the difference.

Immediately the tank temps started to go in opposite directions especially the evaporator tank. A short time later we increased the evaporator tank pump speed to see if we could further increase the difference.  We probably wasted 30 min. of battery life with the fan and pump at too low of a flow rate, but that is what testing is for.

After about an hour we took off the top of the condenser and evaporator tanks to inspect them. The evaporator tank was extremely warm (88 degrees). This part of the system including the evaporator peltiers was performing well.

The condenser tank temp was staying roughly the same which surprised us as we thought that temp would be in the 60's. Our condenser peltiers were cooling the water, but not enough. We were having too much energy loss as it moved in and through the tank and peltier cooling blocks.

The condenser radiators had beads of water on them as you will see in the image and video below. If we run the DM considerably longer it would start to drip clean water into the lower tank. It is just a matter of time and energy.

Seeing the condensation and visible water beads validated our proof of concept for this project.

We will test the DM for a longer period to try to get a gauge on how much water it can produce.

Things we are pleased with:
Evaporator peltiers
LCD display/Arduino with thermistors
Circulation fan
Control panel for all the pumps and fans
No part burned up or wire overheated! Everything worked!

Things we are disappointed in:
Condenser peltiers...we expected them produce a lower temp. A possible reason for this is we only have 3 cooling peltiers as opposed to 4 for the evaporator.

Data on temps and time when condensation occurred for the DM.

A look at the LCD display showing the temps gathered from our thermistors. This worked exceptionally well!

If you look closely you will see the condensation formed on the condenser module proving the concept works.
A video was placed below which provides a better look at this.

A look at the LCD display with the thermistors gathering temps at four locations.

This is probably the most important video of this blog. You see the condensation formed on the radiator. As long as we keep running the machine, this will eventually drop down to our clean water collection tank.

Clean water dripping from the collection tank to a glass bowl. More testing will need to be

done to see how much water it can make per hour.