Generating process and room cooling as well as room heating using solar thermal energy

Mayr-Melnhof Karton AG | SOLITERM Group

The manufacturer of recycled paper-based cardboard and producer of collapsible boxes integrated high-temperature solar thermal systems into its site in Izmir, Turkey. These systems can be used for both heating and process cooling.

Parabolic trough collectors

Participating companies

Mayr-Melnhof Karton AG and SOLITERM Group


Project location

Izmir, Turkey/Germany


Cardboard and collapsible boxes

Technologies used

500 parabolic trough collectors (net area – approximately 4,500 m²), two-stage absorption chiller, high-temperature storage, utilisation of artificial intelligence to control the cooling and heating supply.

Energy efficiency

Reduction of energy consumption by using solar thermal energy: 5,523,000 kWh/yr (relative reduction: 31%)

CO2 savings

3,040 t CO2e/yr



Payback period

6.3 years

Funding programmes



Mayr-Melnhof Karton AG (MMGRAPHIA), based in Vienna, Austria, manufactures recycled paper-based cardboard and produces collapsible boxes. Mayr-Melnhof Graphia Izmir is a specialist in cigarette packaging, gravure and offset printing as well as the production of innovative and highly refined collapsible boxes.

The heating and cooling of the cardboard production plant was originally powered entirely with natural gas and electricity. The factory used two electric compression chillers for both process cooling and room cooling.

In 2020, in cooperation with the SOLITERM Group, the company set up high-temperature solar thermal systems for both heating and process cooling as well as for room cooling. The parabolic trough collectors concentrate the sun’s rays onto absorbers in the centre of the collectors. The hot water (170–180°C) is converted into coolant in a two-stage absorption chiller, and excess heat is collected directly in a high-temperature storage tank. Doing this enables the system’s energy requirement to be met at night or on cloudy days by using solar thermal energy as its primary source. In summer, this system provides an average of 3,000 kW (3,500 kW peak) of usable solar cooling. If the stored solar heat is not sufficient for night-time operation, the necessary additional heat is provided by a natural gas boiler. In the production plant, approximately 80 per cent of the electricity required in summer and 60 per cent of the thermal energy required in winter can be provided by CO2-free, high-temperature solar thermal energy.

The entire system is controlled by AI and digitalised, making it largely autonomous. The collectors use an intelligent control system to track the sun automatically, and the temperatures and pressures in all the major components and pipelines are monitored, thereby optimising the energy supply. In relation to the total energy consumption of the plants in Izmir, this project can reduce energy consumption by more than 30 per cent.

Another picture of the parabolic trough collectors


Particularly relevant industries include: food, chemical, textile, supermarkets, hospitals, hotels and shopping centres. However, a sufficiently large area must be available for the collectors. This project is transferable as seasonal heat storage for district heating suppliers (current project development with STAWAG in conjunction with long-term storage [45,000 m³]).

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Pictures: Soliterm GmbH