A Low-Pressure Solar Geyser (also referred to as a close coupled unit) is popular for many reasons, but there are two main attractions.
The first is the Solar Power aspect. There's is no need for any external electricity sources. Secondly, it's a very basic setup.
To heat water on a daily basis you literally only need the sun's radiation. Another reason why a Low-Pressure solar geyser system is popular can be the fact that there are no moving parts involved, bringing us back to the simplicity of the system.
But how exactly will it work you wonder? With no pumps to circulate the heated water, how can it heat a large tank filled with cold water?
The Design of a Low-Pressure Solar Geyser
The first thing you have to understand is that a Low-Pressure system usually comes as a complete package. This will include the tank and the tube collector, stand and auxiliary tank.
Low-Pressure systems are Closed coupled systems, meaning that the tubes connect directly into the tank.
Heated water is pushed up the pipes filling the tank with the hot water and subsequently pushing the cold water back down into the tubes for re-heating. This process happens continuously throughout the day.
When the Low-Pressure solar geyser is installed, the tank is placed at the top and the collector at the bottom. A small section of the tubes leads into the tank, which establishes a direct connection between the two.
Given the way it's assembled, there's no need for a pump to circulate the water. Instead, the natural process of gravity will make sure the hot water inside the tubes move up, while the cold water moves down. This is referred to as a thermosiphon process.
Cold water is essentially heavier than hot water, and it will kick-start the convection cycle.[products_slider slide_to_show="3" limit="5" dots="false" cats="240"]
Mentioned earlier, the two main benefits that these units are the most simple solution to heating water and that they are extremely cost effective.
The overall package is also more affordable because there aren't any complicated components involved.
However, the benefits don't stop there. Provided that there are less pressure and strain on the tank, it typically lasts longer. Add to this the lightweight components and the incredible efficiency, you've got a Solar Geyser that won't stress you out.
There are three challenges to consider though. The first is that the water pressure is gravity created, therefore the distance above the taps will determine the pressure of the water that comes out of them.
The second challenge is when one of the tubes fail. If this happens the entire system needs to be shut down before repairs can be made. But if controlled and installed correctly, there shouldn't be any temperature problems.
As for a single tube breaking, it doesn't happen very often. The third is if you use a low-pressure system in a residence that has municipal water pressure, the mixing of the hot and cold can be a challenge because the cold water overpowers the hot water, for which in winter ends up being either soft hot water of warm medium pressure.
So, if you're looking for a basic, efficient and affordable Solar Geyser system, you should definitely consider a low pressure one.