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HECTAPUS — Heating Cooling Transition and Acceleration with Phase Change Energy Utilization Storage

The European Geothermica ERA-Net and the Joint Programming Platform Smart Energy Systems ERA-Net have launched Joint Call 2021, Accelerating the Heating and Cooling Transition. This initiative aims to enhance collaboration among national and regional programmes dedicated to integrating energy systems and advancing heating and cooling technologies. Under this framework, the HECTAPUS project focuses on exploring the possibilities of integrating Phase Change Materials (PCMs) with underground thermal energy storage and heat pump technologies together with six partners from Norway, Türkiye, and Sweden.


Approximately half of the global energy supply is dedicated to heat generation, with 28.6% to fuel and 22.7% to electricity [1]. While less than 10% of this heat is generated from renewable sources. Recognizing the need for a sustainable shift, the European Technology and Innovation Platform on Renewable Heating and Cooling (RHC-ETIP) unveiled a visionary plan in 2019, aiming to achieve 100% renewable heating and cooling in Europe by 2050. [2] Thermal energy storage plays critical role in attaining this goal by eliminating the mismatch of time and space between supply and demand. It ensures the stability of both electricity grids and thermal networks, particularly during the integration of intermittent renewable energy sources. Phase Change Material (PCM) is renowned for its high storage density and the steady temperature output it offers during its phase change process. On the other hand, Underground Thermal Energy Storage (UTES) is known for its substantial storage capacity is catering to seasonal storage needs.

The concept of combining these two technologies to address both short-term and long-term storage demand has gained attention. However, there are knowledge gaps exist in the literature regarding their technical performance in real-scale applications and the methodologies required to assess and evaluate such systems comprehensively. Additionally, there is a lack of life cycle analysis (LCA) and life cycle costs (LCC) for developing business cases. The HECTAPUS project will provide clarity on the technical, economic, and environmental aspects of PCM integrated UTES for stakeholders in the energy sector.

HECTAPUS project represents a step forward in several Sustainable Development Goals (SDGs). It contributes to SDG 7 (Affordable and Clean Energy), SDG 9 (Industry, Innovation, and Infrastructure), SDG 11 (Sustainable Cities and Communities), and SDG 13 (Climate Action).

Figure 1. 5 Work Packages (WPs) will be delivered in parallel.

Aim and Objectives

The primary goal of the project is to create versatile, energy-efficient, and cost-effective heating and cooling solutions through the integration of PCM storage systems. To achieve this objective, the following key objectives (KOs) have been established:

KO 1: Conduct long-term measurements of energy systems incorporating PCM storage in different climate zones and formulate a methodology for assessing system performance.

KO 2: Refine the design and operation of PCM storage systems to cater to various applications under diverse operating conditions.

KO 3: Enhance the design and operation of integrated UTES systems with the incorporation of PCM storage.

KO 4: Develop comprehensive business cases for the effective utilization of PCM storage integrated into energy systems.

Project partners

NORCE Norwegian Research Centre (Norway)

COWI AS (Norway)

Cukurova University (Türkiye)

Barış Technological Installation Systems Industry and Trade Co. Ltd. (Türkiye)

KTH Royal Institute of Technology (Sweden)

Huurre Sweden AB (Sweden)

Figure 2. Participants from research institutes and industry

Funding is provided by Swedish Energy Agency and local funding agencies respectively.

Timeframe: 2023-2026


Principal Investigator

Other Involved Personnel


[1] REN21, Renewables 2023 Global Status Report collection, Renewables in Energy Supply. Paris: REN21 Secretariat, 2023.

[2] RHC, 2050 vision for 100% renewable heating and cooling in Europe. 2019.

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