Solar thermal energy is a technology designed to use sunlight to obtain thermal energy (heat). This heat is often used to heat water used in homes, businesses, swimming pools, and to heat the interior of a building (space heating).
In order to heat the water using sunlight, the solar collector heats the working fluid pumped through it. The working fluid is heated as it is pumped through the collector. The now heated fluid is then pumped out of the collector and through the heat exchanger.
The heat exchanger is usually made of copper and is usually located in a solar energy storage tank. This allows the heat transfer in the fluid - to be exchanged into the water in the storage tank.
The tank is the basic component of any solar thermal system because it stores all the heat generated by the solar collector for use when needed.
Solar collectors are classified by the Energy Information Administration (EIA) as high, medium or low temperature collectors.
Here we talk about medium temperature solar collectors, which are commonly referred to as solar water heating systems in the form of flat plates or vacuum tube collectors. These collectors are used for collection, storage, use of heat for domestic hot water (eg for showers, laundry or process applications, etc.), for space heating and for space cooling (using various types of heat-driven cooling systems, such as absorption chiller)
Evacuated Tube Collectors
The evacuated tube collector (ETC) is very effective in retaining most of the heat collected from the sun. Each tube operates independently of the other tubes and is surrounded by a double-walled glass tube. There is a deep vacuum between the double walls, creating a "thermos" effect that greatly increases its thermal insulation. This design allows sunlight to pass through the glass but allows for little heat to escape.
In many vacuum tube collectors, such as SFB305818, heat pipe technology is used. The copper heat pipe is located in the vacuum tube and is fixed by a thin metal sheet called the aluminum fin. The heat pipe is also under vacuum, which allows the water inside to boil at a lower temperature.
When the water boils, the steam rises to the top of the heat pipe, which is located in the header of the collector. Water or a heat transfer fluid (usually a water) is passed through the header where it contacts the top of the heat pipe to rapidly heat up. It then passes through a heat exchanger, usually a part of a tank, to store heat for immediate or future use.
Flat Plate Collectors
Flat plate collectors are usually composed of a series of copper tubes in a well insulated glass box. The sun shines on the glass, the heat is trapped and held inside by heavy insulation. As water or heat transfer fluid passes through the collector, heat trapped from the sun is transferred to the fluid.
The fluid is then heated and recycled back through the heat exchanger to store heat in the heat exchanger for immediate or later use in a domestic hot water or space heating system.
Sunflower can provide both of them, evacuated tube solar collector or flat plate solar collector. Heat pipe solar collector has longer service life. In areas where the air is highly corrosive, such as by the sea, heat pipe collectors are recommended. The flat plate collector is best suited for users who live in hot places with high temperature all year round.
If you have any interests to use solar thermal collectors for domestic hot water or projects, for example, pool heating, space heating etc, you can find details below