A parabolic trough is used to reflect direct solar radiation towards a pipe that contains a receiver fluid which runs through the trough. You can make a DIY solar heating parabolic trough for your home. It can be used as a solar cooker, or a way to heat your water supply.
For this simple DIY project you’ll need 20”x4’ aluminum flashing, 1x8x4’ wood, ½” copper tubing, and some drywall nails. You’ll be using a jig saw, hammer and a drill with ¾” drill bit. This is all you need to acquire for the solar heating parabolic trough.
The first thing you need to do is to cut the 1x8x4 into half. Take one of the boards and draw a grid with one inch increments. The grid will be used to plot the positive y values with the formula y=x²/4p.
If you don’t want to compute you can use the graph below as guide:
Once you’ve plotted the parabola, cut it out using a jig saw.
Then use it as a pattern to cut the other board. These boards will serve as your end pieces.
Drill a ¾” hole near the focal point of the parabola, where the copper tube will be inserted. This will gather the heat from the sun solar radiation.
The next step is to make the reflective panels for your solar heating parabolic trough. You will need someone to help you holding things. Take the aluminum flashing and nail it to the end boards. You could pre-drill the holes in the aluminum flashing to make your job easier.
Now you made a DIY solar heating parabolic trough. You can improve on it by placing furring strips on either side of the trough. The strips make the flashing more durable and provide a place here you can attach the glazing. You could use glass or a piece of clear plastic to cover your trough. To use it as a water heating system, water is fed through the copper tube at a uniform flow rate.
An alternative way to create DIY solar heating with a parabolic trough is the procedure shown in the video below:
The DIY solar heating parabolic trough in this video might be more expensive. The mirror-like reflector he used costs around $15 per linear foot.
Plus, the efficiency will be improved if a black PVC pipe is used instead of a white one.