Tyhjiöputkikeräimissä

Tyhjiöputkikeräimet, often translated as vacuum tube collectors, are a type of solar thermal collector that utilizes a vacuum to enhance heat transfer efficiency. Unlike flat-plate collectors, tyhjiöputkikeräimet consist of a series of evacuated glass tubes. Each tube typically contains an absorber plate or a heat pipe, which is selectively coated to maximize solar radiation absorption and minimize heat emission. The vacuum between the outer glass tube and the inner absorber tube acts as an excellent insulator, significantly reducing heat loss through convection and conduction. This insulation is key to their superior performance, especially in colder climates or on cloudy days, as it allows them to maintain higher temperatures for longer periods.

The absorbed solar energy heats a fluid circulating through the collector. This fluid can be water, an antifreeze solution, or air, depending on the specific application. The heated fluid is then transported to a storage tank or used directly for heating purposes, such as domestic hot water, space heating, or even industrial processes. The evacuated tubes are mounted in an array on a roof or other sun-exposed surface, angled to optimize solar gain. Their design also offers advantages in terms of durability and resistance to environmental factors like dust and dirt, as the absorber is protected by the glass tubes.