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DIY Solar Water Heating is your first step in contributing to the sustainability of our environment for generations to come.....

DIY Solar Water Heating is one of the only things we as responsible home owners can currently do to contribute to the sustainability of our environment. The other options (wind and hydro power) are just too expensive at this stage.

And I will be honest with you.... up till very recently, I just could not convince myself that a solar water heating system is really worth it. I looked at the cost of a system, and the value it would add to my home, as well as to the ROI (return on investment) I would get back, and the maths just didn't make sense to me.

If I calculated the cost, compared to the financial savings I would make by my reduced electricity bill each month, and then guess how long after the five year warranty I would have to replace the system because of defects..... it just did not make financial sense

Remember that us as responsible "carers" of our beautiful earth, also need to look at the cost of disposing of the system once it's useful "life" is over. This all adds to the cost of the overall system and has a big impact on your ROI.

In order for a system to have minimum impact on the environment, it must have a long enough life to justify the use thereof. There is no point in using "environmentally friendly" technology, and then the system only lasts for 3 to 5 years (if you are lucky!). The disposal impacts negatively on the environment, even if we do dispose of it correctly, which most people don't do.... at least not is South Africa.

We get a lot of diy solar water heating imports, that just weren't designed for our climate or harsh weather conditions. These systems will normally come with a three or five year warranty (whatever that means....)

And I still don't believe that a system can repay itself within 5 years, even with relatively expensive electricity costs from "traditional sources" such as oil, gas and coal. Until recently, the manufacturing costs of solar panels were just too expensive. There are various reasons for this:

  • Ineffective designs
  • Low turnaround, etc etc.

Cheap diy solar water heating systems were financially affordable, but didn't last long and good systems were so prohibitively expensive that we had no chance of recouping our costs over the guarantee period.

It became clear that imported products have definite shortcomings. South Africa has one of the highest solar radiation levels in the world and most imported systems are at best suited to colder environments and therefor these systems just do not last in our harsh climate.

Recently, with the soaring electricity tariffs, not only in South Africa, but worldwide, I and other homeowners are starting to look at solar water heating again..... JUST maybe the maths makes more sense now!

After lots of research, I realised that it does make sense now, but we have to be careful with which solar water heating system we select as it is amazing what can actually go wrong with your solar water heating system! This makes for some interesting reading..... 

So is there a viable solution?

Yes, there is, but before we look at what diy solar water heating system will be best suited for your requirement, let's just quickly see what can go wrong if you select the wrong system, and what impact that will have on your cash flow (and your peace of mind....)

Solar water heating systems, wonderful weather and an abundance of sunlight, is the ideal match, but we have to know about the following "hazards" and drawbacks to get the most out of the deal:

1. Maintenance

Solar water heating systems require regular care and maintenance. It is like anything else...... neglect your solar water heating system at your own peril !

If not cared for, the system will not perform optimally and it will start to fail long before you see a return on your investment.

So take care to select a reliable, well-designed system that requires little maintenance and then do that maintenance diligently.

2. Stagnation

Stagnation, where the system overheats because of under usage, is a huge issue, especially for evacuated tubes. Runaway heating can cause internal temperatures to rise as high as 200 degrees Celsius.

Apart from creating a serious hazard, this degrades the insulation around the pipes, drastically reduces the life of the water cylinder, and ultimately wastes water by causing the safety valve to open and the overflow to dump the water.

This paragraph courtesy of the Popular Mechanics magazine, August 2013

Stagnation occur when the solar collector cannot adequately reject the absorbed solar heat to its primary heat transfer fluid. This results in the collector and heat transfer fluid to reach temperatures far exceeding that of the design limits.

This can happen under any of the following conditions:

  • Prolonged sunny conditions,

    (EV tubes are designed for arctic conditions and is therefor to efficient for warmer climates)
  • Under usage,

    (typically during holiday periods when the family is away)
  • Power outages,

    (whoa, don't we know about that here in our beautiful South Africa)
  • System servicing periods,
  • Due to energy storage capacity limitations.

This paragraph courtesy of the webpage

3. Freezing Temperatures

At the opposite end of the scale, as ambient temperatures drop below zero, is the issue of freezing. This causes water trapped in flat-panel systems to expand and pop their copper channels.

Then, as it gets warmer, you effectively end up with an expensive leaking sieve bolted to your roof.

To overcome the system, indirect heating systems – where the panel is filled with an anti-freeze solution that passes through a heat transfer unit – were developed.

However, the anti-freeze needs to be topped up on a regular basis and replaced biannually, which adds to the hassle factor.

There is also a drop in efficiency of at least 30% because the water is not heated directly.

This paragraph courtesy of the Popular Mechanics magazine, August 2013

4. Water Quality

If you live in an area or a country where the water quality is deteriorating, then the following will have a huge effect on your diy solar water heating system:

  • Many areas now have high levels of dissolved solids in the water, which blocks pipes in the panels and renders them ineffective.
  • To remove the sludge, you have to disconnect everything and flush the system with a mild acid. It is a huge job and even then you are lucky if you get half of the sludge out.
  • Municipalities are forced to add excessive amounts of chlorine to the water to kill bacteria; this plays havoc with stainless steel components.

Some contents of this paragraph courtesy of the Popular Mechanics magazine, August 2013

5. Complexity

The complexity of many diy solar water heating systems doesn’t make for easy installation, which confuses both the diy enthusiast and if you use an accredited installer, even them!

So what is the solution then you may ask?

Well, the most important thing I wanted to highlight here was that you know what to look out for when you select your diy solar water heating system, as the wrong choice will NOT add to the value of your home and will cause you huge amounts of frustration.

Follow this link for an excellent system solution.

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