Tyhjiöputkikeräimien

Tyhjiöputkikeräimet, known in English as vacuum tube collectors, are a type of solar thermal collector. They are designed to absorb solar radiation and convert it into heat. The key feature of these collectors is the use of evacuated tubes, which are typically made of glass. Each tube contains an absorber plate, often coated with a selective material to maximize solar absorption and minimize heat loss.

The space between the outer glass tube and an inner absorber tube is evacuated, creating a vacuum. This vacuum acts as an excellent insulator, significantly reducing heat loss through convection and conduction. This insulation is more effective than that found in flat plate collectors, especially in colder or windier conditions. The vacuum helps to maintain a higher absorber temperature, leading to greater efficiency in converting sunlight into usable heat.

Inside the vacuum tube, a heat transfer fluid, such as water or an antifreeze solution, circulates. As sunlight strikes the absorber plate, it heats the fluid within. This heated fluid can then be transported to a storage tank for later use, typically for domestic hot water or space heating. In some systems, direct steam generation is also possible.

Tyhjiöputkikeräimet are known for their high efficiency, particularly in colder climates and during winter months, due to their superior insulation properties. They are also often more aesthetically pleasing than flat plate collectors. However, they can be more expensive to manufacture and install. Their construction is also more complex, involving the sealing of vacuum tubes. Despite these factors, their performance advantages make them a popular choice in many solar thermal applications.