The evacuated tube solar water heater is a highly efficient solar heater, which is capable of converting 90% of the solar energy received into heat, which helps in heating water.
These types of water heaters are also known as vacuum tube heaters and are typically constructed from durable glass.
In most countries including North America and Europe, you will find that the evacuated tubes of this type of solar heater being made from heat resistant and ultra strong Pyrex and will most often than not have a double wall construction.
Here’s an image of an evacuated tube:
The inner tube of the evacuated tube is made from durable glass and is mostly coated with a type of coating, which is able to absorb sunlight. The inner surface of the inner tube consists of reflective coating.
How Evacuated Tube Solar Water Heaters Work
An evacuated tube solar water heater consists of multiple tubes. The air in each of the tubes is removed to create a vacuum. At the center of each tube, there is a copper heat pipe for absorbing and transferring heat.
Basically, when you install evacuated tube water heater, the copper heat pipe containing an anti-freeze liquid, is the element that absorbs all the infra-red radiation and/or heat from the sun and transforms it into heat.
When heat rises, the heater system automatically releases hot antifreeze which rises right up to the top of the system’s heat pipe. Here, the copper tip is connected to a header pipe, the latter releasing higher amount of antifreeze.
The hot antifreeze is automatically pumped by the system through the pipes situated inside a hot water tank. As a result, the water becomes hot while the antifreeze becomes cool. This is a continuous process and the antifreeze after becoming cooler again moves around the heating system and goes back into the header pipe to be reheated.
The evacuated tube solar water heater is a simple system that needs minimum maintenance. Due to the presence of copper at the tip of the system’s heat tube, it is able to heat water to almost 900C or 1940F in summers and 900C or 1400F in winters. The idea is that whatever the weather be; you will always get hot water in your home.
All solar water heaters have advantages over electrical water heaters in terms of level of efficiency and energy and cost saving factors. Apart from helping lower the energy bills of your home, there are various advantages that different solar water heaters have.
One of the primary advantages of the evacuated tube solar water heater is that they can work very well even in cold winter months thanks to the antifreeze.
Most basic or simple solar water heaters work very well in hot or warm weather and not so well in cold or freezing temperatures. But that is not the case with the evacuated tube heater.
One of the key factors for its high performance in the winter months is the vacuum in the evacuated tube. The vacuum effectively prevents the heat tube from becoming cooler due to the outside temperature which could be below freezing.
Even during cloudy days, the evacuated tubes can absorb enough sunlight to create heat and heat water up to almost 500C or 1220F.
There are different types of models of evacuated tube solar water heaters available in the market today. Most models differ in number of evacuated tubes attached to the system.
You can find water heaters having anywhere from 10 tubes to 30 tubes and even more.
Most top of the line systems are SRCC OG-100 certified but you should always double check it for guaranteed high performance.
Here’s how the evacuated tubes look like:
You can install the evacuated tubes on the rooftops or even in your front garden depending on convenience and where it can get maximum sunlight. You can opt for a DIY kit for self installation at home or call on an expert in plumbing skills. The installation is practically easy and once completed, you can start getting hot water within hours.
The most important fact of evacuated tube solar water heater is that it takes less space, doesn’t make a hole in your pocket when it comes to energy bills, and ensures a steady supply of hot water throughout the year without high maintenance.