SOLAR WATER HEATING TYPES AND AESTHETICS
SOLAR WATER HEATING TYPES AND AESTHETICS
Arguments as to which is a better or worse type of solar water heating system I believe comes down to the maths.
At it’s simplest, which system provides the fastest payback on capital and the best returns on investment?
THE STARTING POINT – IS IT COMPLIANT?
There are many solar water heating systems to choose from. Some are legal and some are non compliant and, if installed are breaking the law.
If a system has been tested and passed the required SANS 1307 test it is a legal system, but requires a SABS Mark to be approved. A pass is (theoretically at least) only valid for 1 year.
With a pass or Mark, they are all arguably safe and reliable and suitable for purpose. They should carry at least a 5-year warranty.
Maintenance requirements may vary, and all good systems should probably be running in around 25 years.
AESTHETICS?
That having been said there are differences particularly when it comes to aesthetics.
Do you want a tank on your roof? or not?
ON ROOF SYSTEMS
If you are prepared to have a tank put on the roof, an integrated system where the tank and solar collector are in one unit can be used. Frequently this will be a tank with evacuated tubes inserted into the cylinder.
It may also be a split system. The tank is separate to the solar collector.
The solar collector will be either a flat plate type, or evacuated tubes type. In both cases there will be pipe work connecting the solar collector to the tank.
In thermo syphon types (where the principles that hot water rises is used), the tank has to be higher than the solar collector, and the tank may be either on the roof, (generally the case) or inside the roof void.
From an appearance perspective an integrated system where tanks and tubes are in one, do not look that attractive and the weight of the system may put structural strains on the roof structure and require reinforcement. Larger systems of 300l are much harder to install with a single big tank.
IN ROOF TANKS AND ON ROOF SOLAR COLLECTORS
When it is forced circulation type, or in other words ‘pumped’, the tank can be below the solar collector, in the roof void, or elsewhere.
Split systems where the tank is separate to the solar collector are generally considered more attractive and less obtrusive in that only the solar collector needs to be located on the roof.
WHICH IS BEST? ADVANTAGES AND DISADVANTAGES
As all solar water heating systems do the same thing, heating water with solar radiation, it really is not a question of which is better or worse.
Hot water performance limitations occur with integrated systems as the width of the solar tank on the roof limits the number of evacuated tubes that can be inserted into the tank. Controlling the temperature in the tank is also much harder to achieve, as the solar collector cannot be turned ‘off’.
Split systems do not have the performance limitations, as the solar collector is separate to the tank. For example, 1 flat plate, or two or three connected can be connected in series to the tank. In much the same way solar manifolds using evacuated tubes can be fitted in series, thereby providing flexibility and differing power outputs.
Thermo syphon systems do not generally have as high a performance as pumped, when the same sized collector is used on the same size of tank.
SUMMARY
For the consumer considering going solar, aesthetics may be a major consideration.
For any consumer, the hot water performance and the financial returns should be the key indicators as to which systems they consider.
In the case of Ubersolar systems, they are split forced circulation indirect types.
They were designed to allow the tank to be located anywhere, on the roof, in the roof, or placed up to 15 metres away.
The solar collectors are modular, from 12 EVT’s in a 100l system to 60 EVT’s in a 300l system, enabling any required power output (kWh savings) to be achieved.
At the same time, as well as providing flexibility of both tank location and collector size, Ubersolar systems do not suffer from overheating when in stagnation.
From a cost reward perspective, Ubersolar systems enjoy faster payback on investment, and provide greater investment returns, as well as providing more hot water output per Rand invested.
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