How To Build A Solar Water Heater
My trailer like most travel trailers it’s size comes equipped with a small water heater and while this is efficient for most of my needs, being a tightwad I’m always looking to save resources and free alternatives.
I only need a few gallons of hot water a day to wash dishes and take a shower so this small set-up works great for me, especially in summer when the sun is at its hottest.
I could have chosen an elaborate solar water heating system (and expensive) but I prefer to keep things simple and cheap.
Total cost for my batch solar water heater was under $5 since most of the components were free for the taking. All you need to make this heater are two cardboard boxes, aluminum foil, tape, an emergency space blanket, and clear plastic sheeting.
Tools needed include a box-cutter or sharp knife and scissors.
A batch solar water heater is nothing more than an insulated box covered with aluminum foil to reflect the suns rays back to the containers inside. The design, I use is idiot simple but you can improve the concept by building your batch container from other materials, constructing a framed glass and hinged door etc.
What you can do is limited only to your imagination.
The concept is simple, heat from the sun is absorbed by the water and the box, the suns rays are also reflected off the aluminum foil back to the bottles speeding up the heating process.
The time it takes for the water to reach a desirable temperature of course depends on season, time of day and other factors.
In July and August, I can have hot water in under an hour but on cooler or cloudy days it can take several hours for the water to become warm enough to shower with or do dishes. It’s not an exact science.
I picked up the cardboard boxes for free at the local hardware store, both were the same size, but one will expand to accommodate the other with a little work. The box I have will hold five 2-litter plastic soda bottles but you can choose a larger or smaller box depending on your needs.
To start, line the inside of box number one with the emergency blanket, (these can be found in the sporting goods department of most department stores) use tape to secure it to the inside the box.
Keep in mind that box number two will be placed inside this one so it is important to leave enough flexibility when securing the emergency blanket to allow for this.
Next, line the inside of box number two with aluminum foil to reflect the suns rays back to the water containers inside. Now fit box number two inside of box number one.
This may take a little cutting and slight modification. I had to cut about one inch off the front the box to make it work, but this should not be much of a problem.
Okay, now you need to cover your box – I used clear plastic sheeting secured with tape around the edges, leaving about ten inches free at the end so I can add and remove my water containers when needed. I tuck this loose plastic underneath the boxes when in use.
Now all you have to do is place your water containers inside the box (I used 2-litter soda bottles), but other containers can be used. Place the solar water heater facing the sun and wait for the water to heat up.
Have ideas on how to improve this design (cheaply) I’d love to hear them in the comments below.