Solar Power Heating systems need to be selected carefully for the area and environment in which we live. By now you have done the following:
I have researched many systems and in the end I found the one which I think is the best system suited for the conditions in South Africa.
It is a locally developed system by solar water heating specialist and entrepreneur, Ettienne Holder. This patented system allows homeowners to enjoy their solar power heating system without the drama and "hassles" that we have found in other imported systems.
The goal when they started out was to design a system that didn't:
Well, you would think that those requirements were a tall order, but after two years' effort, they found what they think is the "perfect solution".
They took their inspiration from evacuated (EV) tubes, use the best characteristics of traditional flat panel designs and then added their own "five cents worth", as they call it.
They then came up with the Novasun Solar Water Heating System.
So what makes this Novasun Solar Water Heating System better for the local climate in South Africa?
Note: Most of the technical information following comes from the webpage of solarassist, the company producing the Novasun Solar Water Heating System of which you will find the link a bit lower down on this page.
First, lets look again at the drawbacks of traditional systems:
Solar geysers which make use of indirect heating, use a heat transfer fluid, typically glycol, (see explanation below) to carry energy from the solar collector and transfer the energy to the water through a heat-exchanger.
The purpose behind this is to prevent environmental damage, i.e. freezing, corrosion and clogging to the solar collectors.
However, most experts agree that there are distinct disadvantages to the use of indirect solar geysers:
Indirect heating systems which are not maintained regularly will experience reduced efficiency, and ultimately it will stop functioning and will have to be replaced at a huge cost.
Solar geysers that make use of direct heating systems (these are the flap panels we all see on the rooftops), are prone to freezing in cold temperatures.
In South Africa, these systems in previous years only received a rebate from our energy provider ESKOM, if they were rated as freeze resistant and were fitted with dump valves.
The dump valves acted as a protection mechanism against freezing and the subsequent damaging of the system if temperatures dropped to below zero. However, these dump valves required ongoing servicing and have been "outlawed" recently.
Standard flat panel solar collectors circular designed pipework is also prone to blockages caused by the build-up of dissolved solids in our water resources. The solids are deposited in the geyser cylinders, pipework and collectors.
So, lets ask the question again.....
What makes this Novasun Solar Water Heating System better than traditional systems?
The patented Novasun Solar Power Heating System allows for the indirect heating of water. Inside its flat panel collector, the Novasun system features thin copper tubes that have been laser welded on to the collector sheet.
Inside each of the sealed tubes is 7 ml of fluid, which Holder describes as a "special mix of herbs and spices" that eliminates any possibility of freezing. The heat transfer fluid's freezing point is -60 degrees C, making it suitable for installation in any of Southern Africa's diverse climates.
(I would say that it will actually be suitable for most colder European and American climates too.)
As the fluid heats up, it becomes a gas, rising and dissipating its heat into a heat exchanger which in turn warms the water. The gas then condenses and falls to the bottom of the tube and the cycle is repeated.
The solar collectors are maintenance free from the perspective that they do not require the replacement of the transfer fluid.
Once the water inside the heat exchanger reaches a temperature of 65 degrees Celsius, the gas can no longer condense and the cycle is halted, preventing stagnation. The system therefor does not need a dump valve to protect it against a sudden drop in ambient temperature or freezing conditions.
The South African Bureau of Standards has therefor rated the system as a direct freeze resistant system and it qualifies for the ESKOM rebate.
The flat panel unit is enclosed by a sheet of low-iron boron glass, making the entire collector completely hail proof.
South Africa experiences many challenges to maintain water quality levels. Dissolved solids in our water resources are on the increase. This is caused by the build-up of minerals, metals and other waste material and this leads to performance problems and failure of traditional solar water heating equipment.
The unique design of the Novasun solar power heating system does not rely on water circulation through a circular designed type pipework and therefor the opportunity for blockages in the system is completely eliminated.
The system is then connected to the proven Solartherm water cylinder, which employs a cross-linked polyethylene (PEX) lining to prevent any grime build-up from dirty water.
The complete installed system comes with a 10-year unconditional guarantee.
This reliability, together with the simplicity of the Novasun Solar Power Heating System design and the ease of installation, make this a very cost effective solar power heating system.
So, did they achieve their original design goals......?
I will leave that for you to answer!