A Solar geyser is unquestionably a magnificent invention for people. Due to its safety and low running cost, solar energy has gained popularity. With a solar geyser, you are able to save up to 40% of an average household water heating expense. Therefore, you have two types of solar water geysers which are pressure and non-pressure.
Firstly, before deciding which solar geyser is best for you, you should understand the fundamental differences between gravity/non-pressure and pressure solar geysers.
The gravity solar geyser is made up of an insulated storage tank, a stand frame and a vacuum glass tube collector. Water is sent to the tank on the roof by a pump or alternatively, from a water tank, then the evacuated glass tubes are filled with water and are exposed to the sun, which heats up the water in the glass tubes.
As the specific gravity of cold water becomes heavier than hot water, the hot water in the glass tubes begins to rise in the insulated water tank, and the cold water in the insulated water tank sinks/drops into the glass tubes. As this cycle is repeated, water in the solar geyser gets heated. This process is known as thermosiphon and is based on natural convection.
Low-pressure solar geysers are normally best suited for use in areas where availability of municipal water supply is problematic, as municipal water is usually pumped throughout the network of underground and above-ground pipes to its location with the use of very powerful pumps and as such is usually considered high-pressure.
In case, you wish to install a low-pressure system in your home with municipal-fed water, you would need to utilize a pressure control valve on the cold water supply to the plumbing system (this will allow mixer taps and showers to have balanced water pressure between hot and cold water). The assistant tank acts as a pressure-reducing valve on the cold water side.
Advantages
This type of solar geyser system is highly effective in converting sunlight into heat
It is usually a cheaper option due to its simplicity
It has a longer life than the main pressure solar geysers as it does not put a lot of pressure on the tank and collectors
Can provide hot water without external power such as pumps
Disadvantages
All the weight of the heater is carried by the roof which may need additional support
It has limited uses with modern plumbing systems, as it can only be used where there is a small head of pressure.
It can cause serious scalding if not installed or used correctly.
The entire solar heating system needs to be shut down even if one glass tube breaks.
Unless it is installed at a high level above the water outlets the water pressure will be very low.
