solar thermal energyHeatwaves have been sweltering around Europe during recent weeks. Although heating of your apartments or buildings might not seem to be a relevant issue right now, it is worthwhile to think about the energy solutions of the building throughout the whole annual cycle. Especially, if you are planning a construction project or energy retrofit. Solar thermal energy can be stored during the summer and taken into use later during winter. During winter, it is still necessary to heat buildings at least in Northern Europe.

Many ways to collect solar thermal energy

The sun is an excellent source of thermal energy, and there are various solutions available on how this energy can be utilized in the heating of buildings. Solar thermal energy can be collected with solar thermal collectors – often installed on the roof of the building. Heating energy can also be collected from the building surroundings, such as asphalt, water, and ground. Heating energy is typically stored either to the ground or to rock through vertical collectors.

Solar thermal energy is mainly stored in the short term, for a few days. This is to even the temperature changes caused by weather or daily variation. However, it is also possible to store solar thermal energy in the long term. Utilizing solar thermal energy in seasonal variation and storing it for several months is possible – and energy-efficient.

Energy piles charge heat to the ground

Seasonal energy storage is being researched at Turku University of Applied Sciences in the LÄMPÖÄ (HEAT) project. “Thermal energy-storing enables economical savings by lowering the production peaks, as a part of the thermal energy needed can be taken into use from the thermal energy storage and utilized outside the production peak”, says senior lecturer Rauli Lautkankare from Turku University of Applied Sciences.

Energy piles, which are either steel or concrete piles with fluid inside, enable thermal energy to be collected and stored during summer and to be used during winter. Simultaneously as the energy piles charge heat to the ground during the warm season, they also enable cooling the building. With energy piles, thermal energy can be stored for months underground charged to rock or water. They enable seasonal heat-storing in both houses and large buildings.

Underground thermal energy storages are being researched and developed

Underground thermal energy storages are under continuous research. They offer both economically and energy efficiently interesting options as energy solutions for buildings. nollaE is also contributing to the research. One of the recent scientific researches about underground thermal energy storages can be read in the article “Micropile Operated Thermal Energy Storages below the Building”. The authors of the article are senior lecturer Rauli Lautkankare from Turku University of Applied Sciences, Nikolas Salomaa, CEO of nollaE, Teppo Arola, Ph.D., and Jouko Lehtonen, D.Sc. The article was recently published in IFCEE 2018: Recent Developments in Geotechnical Engineering Practice.

The sun keeps shining and producing heat also during the forthcoming summers. This energy is valuable and yields savings in energy costs. If you are interested in storing solar thermal energy and benefiting from this nearly infinite energy source, contact us.