THE Namibian solar water heating industry is engaged in a battle of solar technologies, as a relatively new technology in the local market, the evacuated-tube technology, makes inroads into a market which has been dominated by flat-plate solar collectors for the past 20 years.
Swakopmund-based Solar Systems Namibia, a specialist in evacuated tube collectors, last month submitted an official complaint to NamPower after it lost a tender to supply 38 solar geysers to a Desert Research Foundation of Namibia (DRFN) energy project at Tsumkwe. The tender was put out by NamPower, under advisement of Emcom Consulting Engineers in Windhoek.
According to Solar Systems Namibia owner Chris King, the evacuated tube technology was not considered for the tender because it is "too efficient".
King claims that while his tender was about N$250 000 less than the successful tender, he was shown the door and not offered a satisfactory explanation for this rejection by NamPower.
The tender specifications issued by NamPower specified flat-plate collectors, automatically excluding alternative solar heater technologies.
King says this was not the first time that solar water heating tenders invited by Government or major institutions specified flat-plate solar collectors, essentially keeping alternative solar heating technologies from entering the local market.
"To tender for such a job is virtually impossible for a small business, because to adhere to these specifications would mean spending a huge amount of time on preparing for the tender."
According to Glenn Howard, the consulting engineer from Emcon, there are a number of reasons why evacuated tube technology is not ideal for the project, and for Namibia's inland conditions in general.
He says the evacuated tube technology faces strenuous heat conditions in Namibia, which could result in a number of problems.
Evacuated tube collectors do work and very effective under certain conditions, he says, but they are so efficient that the water could potentially boil in summer, which is potentially dangerous.
He says because the evacuated tubes do not lose a lot of heat, they are very effective in colder and less sunny climates.
In Namibia, with its hot and sunny conditions, an evacuated tube solar heater could overheat and eventually explode, according to Howard.
He says evacuated tubes are selling well internationally, but the flat plate "is not dead and there are good reasons for that".
Howard admits that as the consulting engineers to the project, they prefer to recommend a product that they know works.
"On a year-round performance basis the evacuated tube does not match the flat plate in our inland conditions," he adds.
Howard says the consulting engineers also put emphasis on SABS certification or any other accepted industry certification from Europe or North America, which gives engineers a chance to look at reports issued by the certifiers.
According to King, his system does have SRCC certification from North America and German certification.
He also says that temperature pressure valves, which come standard with each tank, prevent water from reaching boiling point and there is therefore no danger of exploding tanks.
Another benefit with the evacuated tube technology, according to King, is that the entire system can be modified easily, as conditions demand.
"You can take out or add tubes with your hands, to size it for your specific hot water needs."
Robert Schultz, the Energy Desk Coordinator of the Desert Research Foundation of Namibia (DRFN), who initiated the Tsumkwe energy project, admits that he understands King's frustration.
He says it is important to allow new technologies to prove themselves, adding that the evacuated tube technology is applied successfully all over the world.
"I would personally have no reservation in procuring evacuated tubes," he says.
Conrad Roedern, managing director of Solar Age Namibia, has over 21 years' experience in the local solar industry.
He says it is important to give the evacuated tube technology time to prove itself in smaller applications, such as for domestic use.
"We welcome pioneers and new technologies," he says.
But for large projects, it is still wiser to use the flat-plate technology, which has proven to have a long life cycle and works effectively in urban and rural areas.
"We should not make Government institutions the guinea pig for testing this technology."
Rather, he says the technology should be given a chance to show its merit under controlled circumstances in cities or towns.
"If you are a private person who buys a system for one third of the price, and you are close to town - even if it breaks after three years - you still make a slight profit."
Roedern agrees that the evacuated tube water heater system is ideal for private households and businesses since it is cheap and can be repaired easily, but adds that the flat-plate technology is still preferred in Namibia for a number of reasons.