Solar Hot Water Systems

Solar hot water panels are the most efficient type of solar panels (using the sun’s energy most efficiently). However, as of 2014, our recommended route for going solar is through a PV system because of the models allowing you to attain it with no cash outlay (or line of credit) required, as was traditionally required for solar PV as well as Solar hot water systems.

Still, solar hot water technologies are becoming more and more effective and cheaper. It’s cost effective and environmentally friendly, so it is worth considering using solar panels in order to satisfy the needs for hot water in your household. It will make you independent from any other sources of energy, rising fuel prices and your electricity bills will be significantly reduced (especially if you have an electric hot water heater (vs a gas).

The solar systems for heating domestic water are made up of several components, the main components of which are solar panels and an insulated hot water tank. There are three main types of solar collectors: flat panel collectors, evacuated tube collectors and vacuum collectors with thermal tubes.

Flat panel solar collectors:
Flat panel solar collectors are the most commonly used type of solar hot water panels since these collectors are the cheapest option for building a solar system for hot water. A coil of copper wire is put in the aluminum framework of the panel. An absorber plate is welded upon them and its function is to absorb sunlight. The plate is usually painted black in order to absorb as much sunlight as possible. The aluminum frame is usually topped with glass in order to increase its effectiveness. Experts recommend the glazed solar collectors for heating domestic and commercial water, as well as for indoor swimming pools. The non-glazed solar collectors are mainly used for heating water in outdoor swimming pools.

Evacuated tube collectors:
Evacuated-tube collectors have a more complex structure than flat solar panels; these collectors are more effective,but are also more expensive. The collectors are made of glass cylinders, which contains small copper tubes. The air between the cylinders and the tubes is pulled out and thus avacuum is created. The reason for this is that vacuum is a very good heat insulator and increases the effectiveness of the system. Usually there is an absorber plate attached to the copper tubes. It is covered with crystals of titanium salt, and is similar to the plate in the flat panels. The cylindersare connected in a common collector. This type of solar panels has a smaller heat loss and much higher efficiency. It is suitable for countries which have four seasons.

Vacuum collectors with thermal tubes:
The vacuum collectors with thermal tubes are the most effective solar hot water systems, but are respectively the most expensive. These collectors work even if the temperature outside is below zero; the system only requires sunshine. These panels resemble the evacuated tube collectors; the difference is that there is no circulating water in the copper tubes. Instead, special liquid is used with low evaporation temperature - usually about 10oC.  These collectors absorb heat from the environment and if the collector surface is touched, it will be cold, even on hot days. The solar energy stored in the fluid reaches a condenser and is thus transmitted to the water. These improvements allow the panels to work effectively in the winter.
The typical lifespan of most of solar hot water panels is about 15 years. There are several factors that you should consider when you choose a solar panel system – you should consider if you have an electric or gas hot water heater (electric water heater users save considerably more – but gas hot water heaters are often subsidized by larger incentives).  Additionally, how is the health of your hot water heater? Is it old? Could it use replacing? Getting a solar hot water system could reduce your costs with that.  You should also heed the orientation of the panels. Orientation to the south, southeast and southwest is considered optimal. The angle of installation depends largely on the location of the building, and it is also extremely important for the system’s efficiency.