Guest Post: How to Build a Solar Concentrator for Solar Hot Water

Blog writer James Vasanth has written to share his insights with readers on the daunting DIY task of building a solar concentrator for solar hot water. He writes, “In this post, I’ll discuss some key points including how to build your own 2-axis parabolic concentrator.” Thanks, James. The “how-to” steps are welcome, however, a ready made version sounds even better after counting all the steps.

For solar hot water enthusiasts, they know that the parabolic dish design is the most efficient way to collect solar hot water. For those DIY, here is a guide on how to build your own 2 axis parabolic concentrator.

The 2-axis means that the solar hot water system will track the sun on the vertical and horizontal axis, which is the most efficient way to harness the suns energy all day

Step 1

You will need to decide how big to build the parabolic concentrator for your solar hot water system.

Shown below are some measurements and values you will have to decide before you start the development of the system

1. GROSS AREA OF PARABOLIC DISH
2. DIMENSION OF PARABOLIC DISH
3. GROSS AREA OF ABSORBER
4. VOLUME OF FLUID IN ABSORBER
5. MAX OPERATING PRESSURE
6. PRESSURE DROP
7. STAGNATION TEMP
8. FLOW RATE
9. PARABOLIC CONCENTRATOR WEIGHT
10. TOTAL WEIGHT OF STRUCTURE
11. MAXIMUM TILT ANGLE
12. MINIMUM TILT ANGLE
13. PERMISSIBLE WIND
14. PERMISSIBLE SNOW LOAD
15. TYPE OF STRUCTURE (roof top or ground installed)

Step 2

Once you have decided on the measurements of the parabolic concentrator, you are ready to start building from scratch or sourcing from suppliers the following items:

• Powertrain
• Slew Drive
• Metal Post
• Absorber Arms
• PVC pipe
• Hose Assembly
• Absorber with temperature sensors built inside
• Reflective Petals
• Truss and Skirting to hold the petals in place to create a parabolic shape
• Tracking System for following the sun (optional). You can try to move the parabolic concentrator manually, but that will require an adjustment of approx.. every 3 minutes

Step 3

Now that you have sourced the parts to make the solar hot water system, you need to look at manufacturing it. You have 2 options, you can either assemble it yourself, or you will contract it out to a manufacturing firm,

Option 1- Assembling the parabolic concentrator yourself will require knowledge of mechanics and for you to be good with tools. You will also need some type of machine to lift the power train and parabolic dish onto the metal post, since it will probably weigh a couple hundred pounds. The pros are that you will know immediately when pieces do not fit right and you can fix them. The con is that you have never done this before and maybe your lack of experience is why the pieces do not fit

Option 2- Contracting out the assembly of the parabolic concentrator to a firm. This is the more expensive option, however it may lead to a fast turn around for a manufactured product. In addition, their experience in mechanical equipment may lead to some good design changes that will make the solar hot water system better. Cons: it is expensive and choosing the right firm may be challenging

Step 4

Once you have a manufactured product, the grand finale awaits; turning on your solar hot water system. In front of all your friends, you can show the sweat, tears and dollars that have been spent on this revolutionary system. Keep in mind, the odds of getting your first prototype as a perfect system, are less than winning the lottery. However, you can boast the 3 years you spent in development and the $200,000 capital investment from friends (no longer), family (no invitations to dinner parties lately) and spouse (in another room of the house) in making your OWN solar concentrator. That is a good thing in one way OR you can just buy a ready made parabolic concentrator that has been installed in over 40 locations worldwide.

The parabolic solar hot water system I am talking about is the SolarBeam Concentrator. It is built in the USA; it has global certifications and is used by companies like Pepsi, Sobeys and universities.

You may want to be an inventor and a pioneer in the DIY, but in this case, it is best to buy a ready made solar hot water system.

Happy inventing and take care!