12 point checklist to buying a solar geyser

Posted by: Yes Solar Cape (Cape Town, South Africa) – 29 October 2010

When purchasing a solar water heating system consider the following 12 points, and evaluate each one before committing to a system.

Yes Solar installation - evacuated tubes

1. Certification – what kind of certification does the system have? First prize is SABS Mark Approval. This is a higher form of certification than just an SABS Test Report. Mark Approval means that the entire supply chain of the product has been inspected and that SABS are confident that the product will consistently meet their standards.

2. Also look out for Solar Keymark certification (EU), and the German TUV standard.

3. Direct versus Indirect systems – basically, if you live near the coast you can install a direct system (no intermediate heat transfer fluid), but if you live somewhere that is prone to frost (i.e. temperatures drop below 4 deg), then you have to go for an indirect system. Where possible, go for a direct system, the heat loss between panel and geyser is lower.

4. Evacuated Tube versus Flat Plate collector – the respective suppliers / manufacturers of these systems place too much emphasis on this question. Rather look at the build quality, efficiency and durability of the collector, regardless of the type of technology it employs. Pay special attention to corrosion resistance – low quality stainless steel and shoddily galvanized metals will start to rust after a couple of years.

5. A quick way to measure efficiency is to look at the rebate a system enjoys. The rebate is simply a multiple of the Q factor of the system (which is a measure of its efficiency). But be careful to compare systems of the same size, e.g. a 200 litre system with a 200 litre system. Continue reading

The age of cheap electricity is at an end

Posted by: Yes Solar Cape (Cape Town, South Africa) – 10 October 2010

The age of cheap electricity in South Africa is at an end. It may pay to consider alternative and renewable energy sources – or to invest in methods of increasing energy efficiency.

Soar water heating - evacuated tubes on frame

Unfortunately, there are several factors working against an easy transition from the Eskom grid to your own little energy island.

Sustainable and renewable energy engineer Frank Spencer, CEO of Emergent Energy, said the immediate problem is that we are in a transition period from cheap to more expensive electricity.

“Our electricity is still too inexpensive to drive behaviour change, but that will change. In addition, our houses are built so poorly that we use a lot of energy to run them, such as poor insulation on geysers, pipes and ceilings, and energy-inefficient appliances,” Spencer said.

“Houses are optimised for upfront costs, not running costs. As with almost every industry, life-cycle costs are seldom considered.”

Getting the best advice on investments in alternative energy sources is not easy, said Spencer. “Most companies are looking to sell some product, which makes it very difficult to get independent advice. Further, there is no reputable accreditation body that I am aware of.” Continue reading

Roll-out of 100000 solar water heaters resumes

Posted by: Yes Solar Cape (Cape Town, South Africa) – 15 September 2010

Three ground-breaking renewable energy projects earmarked for Nelson Mandela Bay with a combined investment value of more than R1-billion are on track, with at least one to start being implemented before the end of the year, top project officials have revealed.

Solar hot water. Evacuated tube installation.

They include the resumed roll- out of up to 100000 solar water heaters (high-pressure solar-powered geysers) to residents after the R900-million project was put on ice in June, as well as a proposed wind farm at Van Stadens consisting of up to 15 giant wind turbines, and methane gas harvesting facilities at the Arlington or Koedoeskloof waste disposal sites.

Because the three projects are being funded by ETA Energy Ltd – a subsidiary of parastatal the Central Energy Fund (CEF) – they are on track and unaffected by the Bay municipality’s cash-flow problems which has seen many infrastructure projects halted.

The three projects will see the metro catapulted to the forefront of attempts by cities around the country to minimise their dependence on energy provider Eskom and its steep annual price increases by “going green”. Continue reading

What to look for when going solar

Posted by: Yes Solar Cape (Cape Town, South Africa) – 31 August 2010

When going solar it is best to ensure that you are getting a quality product and system.

Conergy's thermosyphen insulation layer is made to perform in cold European conditions.

Solar systems are subjected to extreme conditions of heat and cold, rain, hail, etc. Unless they are carefully designed, they may have only a short life and will then not be economical in the long run.

A solar hot water system should last 15 to 20 years. Warranties vary, so look for a product that offers a 10-year warranty on the tank and panels.

A simple measure of a system’s efficiency would be the value of the Eskom rebate attributed to that system, providing that you ensure a like-for-like analysis, e.g. comparing a 150 litre against a 300 litre would not be a fair comparison.

Thermosyphon systems are normally complete on-roof hot water systems. The bottom of the tank has to be above the top of the collector (solar panels), for the thermosyphon action to work. These systems are low on maintenance since there are no moving parts.

In indirect (closed) systems, due to the solar radiation and differences in the specific weight of cold and hot fluids, the heat exchange fluid rises to the top of the collector. From here it flows into the heat exchanger of the storage tank and heats the water in the tank.

Flowing out of the heat exchanger the cold heat exchange fluid in turn flows back into the collector and is heated there. The heated water then flows into the hot water lines and can be used directly for cooking, washing or showering.

Look for the heat exchanger process. Some systems offer only a partial jacket heat exchanger or use an element along the axes of the tank. Make sure that you opt for a full jacket heat exchanger. This will provide greatly increased heating efficiencies.

Check the tank insulation. Polyurethane of 60mm maximises heat retention. This will ensure that heat loss is slowed down, especially during the night when its cold.

Only SABS approved systems qualify for the Eskom rebate. A SABS test report does not imply SABS approval. Look for the SABS stamp of approval.

Five good reasons to go solar

Posted by: Yes Solar Cape (Cape Town, South Africa) – 28 August 2010

Solar water heating is gaining popularity all over the world due to the many benefits it offers and because it is relatively inexpensive and easy to install. With the South African climate our high levels of irradiation make the installation of solar water heaters a sensible choice.

Annual Solar Radiation for South Africa

The following are 5 good reasons to go Solar:

Power Shortage – South Africa cannot currently meet the energy demand in the country with existing power generation capacity.

Rising Energy Costs – Electricity costs are still low in SA, but Eskom forces a 25 % price increase per annum over four years.

Independence from providers – Solar energy ensures continued power supply on key appliances at home or in the office, thereby mitigating damage during power surges and outages. It reduces the household reliance on Main Grid Energy supply, and it ensures hot water during load shedding.

Free Energy – Solar Energy is free, which translates into monthly costs savings on electricity bill. South Africa is one of the regions with the highest solar irradiation in the world. Solar Energy allows you to meet 90% or more of your hot water requirements at no charge once you have recovered the installation costs.

Environmental Footprint – In South Africa, the most abundant source of energy is coal, which is responsible for CO2 pollution. A 150 litre solar water heater can replace on average 4.5 kWh of electricity per day, resulting in environmental annual savings of 3.0 tonnes of CO2 and 12.2 kg of NOx.