Here is another one of my project for Hot Summer days. The idea was to build a portable air-con for my partner during camping in our vehicle or tent at the same time I can use it at home. You can search under Youtube "DIY Air Conditioner". I have seen most of Youtube videos. Most of them used ice-cooler box which I felt it was too big. I needed something small and yet produce the same effect, easy to construct with minimum cost.
|20L Cooler Box|
I thought of using our 20L cooler box, it was perfect, the holes were already on the tray but found the cooler box was still oversize. I knew we have a couple more smaller cooler bags, finally found a damaged Rubbermaid 10L cooler bag hidden in the cardboard. Now that was something I can live with, not too big or too small and most important, easy to carry around and small enough for storage.
The Rubbermaid cooler bag had a leak and was not insulating properly but I decided to give it a shot. I found a way to make the top lid easily, using a left over mooncake box, took few measurements and cut the cardboard size but found out it was too small. Second cut I gave more allowance.
|size and weight difference|
Note: The top lid is a Duct Tape Cardboard Construction. Duct tape will provide some insulation and water proofing for the cardboard. I had used a one inch duct tape which is much easier to work with for this size.
225 x 140mm size
Air outlet funnel design
using duct tap to secure in place
Duct tape around all the corners of the cardboard.
The funnel I decided to use red duct tape just to make it nicer.
place the fan on the top cover and trace the interior diameter with a pen
cut the shape out
more duct tapping for protection and insulation
soldering the cigarette lighter plug. RED is positive on the top and BLACK is negative
using a 12V fan, 0.26Amp
Note: higher the amp the faster the fan turns
fully duct tapped carboard
I have used one bottle of freeze salt water and another just water for melt down test, the rest were freeze packs. The idea is to use freeze PET bottle but I need to know if salt water melts slower and maintains a lower temperature.
110Vac - 12Vdc converter. You should get this converter if you are car or RV camping. Great to use on campsites with power supply.
getting the cold air flow
room temp was 29.4C, at the air outlet temp was 25.4C
everything sits in place and zipped down for transportation
Portable, lightweight and easy to carry.
Unlike a home air con unit, this portable unit depends very much on the room temperature. The warmer the room temperature, less cold conditioned air temperature is produce, however at 29.4 deg C room temperature, you can get 4 deg C difference which was very satisfying.
Another point to note because I tested in a room which was much bigger than the tent interior or vehicle, it did affect the outlet air temperature. This unit will be used only in the evening to cool down either the interior of the tent or vehicle cabin.
Since this is a small unit, I do not expect it to cool my whole room or blow cool air 5mtrs away from me, I have placed it under my workstation and was overwhelmed by the cool air, my partner was pleased too. Well at least it brought the heat down where I was working. Ideal for Summer use at home or work and save your utility bills.
For the fan type, you have to decide, 5V, 12V, 24V or 110V. I wanted a 5V but there was not any so I decided to use a 12V. Do note the faster the fan turns, the higher your power consumption and also the ice will melt faster, plus it will be nosier. The fan I got was alright, not really powerful but at least it was quieter.
The PET Salt water bottle did melt slower and the exterior had icing around it. I will try to get all PET bottle with salt water.
Note: Do not fill the bottle completely, water will expand when freeze.
If you planning to make one which it took me less than 2hr to construct if I had everything in place. The tools used were simple and it was not a messy construction. One idea you can use a carton box but you must insulate the box interior maybe with some Styrofoam and Aluminium foil or duct tape.
Cost and Material
1 useless cooler bag
cigarette lighter plug NT10
Soldiering iron and flux
screws for fan
100vAC 12vDC converter
maybe some extension wire
My next task is to insulate the cooler bag better, intention is to place cardboards all around the interior and duct tape it. Since this is a quick DIY, the electrical connection might have to rework. Need to find a better solution so I can use with my portable battery pack.
If you have any questions, feel free to ask.