Turku Market Square and Toriparkki represent a future energy solution based on harnessing waste heat. In the future, the maintenance of the ice-free market square will be managed using thermal energy stored in the clay layers of the earth during the summer. The energy system of Turku Toriparkki is one step towards a carbon-neutral future for Turku.
Large amounts of heat go to waste in various places, including industrial facilities, data centers, and greenhouses. Even paved areas generate heat during summer heatwaves. In Finland alone, industrial waste heat is estimated at around 54 TWh (2010).
The estimated value of waste heat is calculated in hundreds of millions. Utilizing this waste heat could signify a new energy revolution in Finland and be a significant means to combat climate change. The utilization of waste heat and thermal energy storage are part of a smart grid, enabling surplus heat to be used efficiently.
“There is an enormous amount of waste and surplus heat. It has not yet been widely understood or harnessed. Finland has the potential to be a trailblazer in this field if there is a collective will,” says Rauli Lautkankare, who is preparing a dissertation on waste heat recovery and seasonal thermal energy storage at Turku University of Applied Sciences.
At Turku University of Applied Sciences, there are projects underway with the support of the European Regional Development Fund, aiming to promote the utilization of waste heat through research, awareness, and collaboration among various stakeholders.
The Turku Market Square is heated using solar energy
In Turku Toripark, solar thermal energy is harnessed. The innovative energy system was designed by the energy efficiency consulting firm nolla_E. Through the simulation and optimization software developed by them, the implementation of this energy solution is financially viable.
In the energy efficiency optimization carried out by nolla_E’s developed software, the energy solution is based on calculations that take into account the individual characteristics of the target location.
“The software calculates thousands of energy-efficient combinations of measures depending on the location and lists the most economically viable and device-independent options. The software has been utilized in designing the energy solution for Toriparkki,” says nolla_E’s CEO Nikolas Salomaa.
In Toriparkki’s energy system, solar heat is collected from the square’s surface during the summer. A collection system is placed under the square’s pavement, transporting solar-heated fluid to energy piles. These energy piles, in turn, transfer heat to the surrounding soil. The heat is stored in clay soil to an average depth of 40 meters below the parking facilities. When the clay mass is completely heated, its thermal capacity is approximately 6.6 MW.
During winter, heat transfers from the heated soil to the fluid circulating in the energy piles, which carries the heat upwards to the Torikansi, keeping the surface of the square ice-free. This process also provides heating to the parking facilities, KOY Turun Metro and KOY Turun Toripaviljongit buildings.
950 tonnes of annual CO2 savings compared to the heat pump solution
Achieving full capacity of the solar thermal storage is estimated to be achieved within five years. In the initial years, carbon-neutral district heating assists with heating, and it serves as the backup heating system for the coming years. During the summer, the amount of thermal energy loaded into the heat storage is 11.2 GWh. This is equivalent to the annual heat consumption of approximately 560 single-family homes.
nolla_E’s designed solution reduces carbon dioxide emissions by approximately 950 tons annually compared to a conventional solution using heat pumps.
Link to a video that provides a more detailed explanation of the operation of Turku Toriparkki’s energy storage: Toriparkki energy system and world’s largest solar thermal energy storage
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