Dual stage swampcooler performance

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May 18, 2017
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I decided to finally build a dual stage swampcooler (also known as indirect swampcooler) , I tested the concept of building one 2 years ago but it was too large/impractical for my van, but it did produce good results during testing.
The only difference between a regular swampcooler and a dual stage swampcooler is the use of a heat exchanger. The heat exchanger uses water from the reservoir to cool the air before it hits the evaporator pads. The colder the air entering the evaporator pads the better the performance.
Using a smaller 120mm heat exchanger fits much better on the smaller containers that I prefer to use in the swampcoolers I build. So far I've been using it for the past 2 weeks and the performance has been good.
The summer here in southern california has been uneventful, no heatwaves to fully test it in worst case scenarios.

This is the swampcooler, air intake/120mm heat exchanger is in the back. In the front is the 120mm exhaust fan. I placed the intake and exhaust on top because it takes up less space in my van, I use 4" flexible ducting to bring the outside air to the swampcooler.
a dua stage swamp cooler 1.jpg

Internal view. I use 2x 12 volt water pumps so I can test it as both as a regular swampcooler and also as a dual stage. When I first built it, I used a water filter to filter the water before it went to the heat exchanger, but it clogged up after 2 days and I removed it.
a dual stage swamp cooler.jpg
These are the early performance results i have got so far. One thing I have been noticing is the air coming out of the swampcooler has been in the 70's during the day. With a regular swampcooler its always been in the 80's and even in the low 90's on very hot days.
The amp use is at full power running 1x 12 volt water pump and the main high rpm 120mm fan, and also a less powerful 120mm fan on the heat exchanger. Water use is about the same as a regular swampcooler, I only had to put 1/2 gallon over
the weekend.
a dual stage swampcoole performance.jpg
I build this over a weekend with parts I already had. I used a 120mm aluminum heat exchanger (20 dollars) , but an improvement would be a copper heat exchanger (40 dollars) , also a more powerful 120mm fan on the heat exchanger might increase the cooling effect. But even as is, its a definite improvement over a regular swampcooler, even though it only drops the temperature 3 or 4 degrees, you can feel it in a real world environment.
according to the max-min thermo hygo thermometer I have it was in the 60's, the weather channel also reported similar 50/60.

Below are more readings I took. With the swampcooler off all day, I took a reading at 5.50pm as soon as I turned the swampcooler on. One hour later I took another reading at 6:42 pm. The outside air reading, is actually the temperature which is inside the flexible ducting connected to the roof, the ducting is inside the van that is why it reads 103, once the fans start pulling the outside air through the ducting it gives a more accurate reading of the outside air temp.
a dual stage swamp hot day.jpg

This other test I recorded the max temperatures my max-min thermo hygro thermometer recorded during 2 days. On one day I didnt run the swampcooler all day, on the second day I left the swampcooler running all day. This was with the van parked in the sun and all windows and doors closed.
a dual swamp max temp.jpg