Heating and cooling of buildings constitutes a significant part of the energy use in the EU, and is therefore an important sector in the transition to a low-carbon society. hybridGEOTABS is an HVAC-concept that provides comfort in buildings in a clean and sustainable way.
The core of the concept is GEOTABS: a combination of a geothermal system and thermally activated building systems (TABS). TABS is a type of radiant heating and cooling emission system, well-known for its thermal comfort. The heating/cooling pipes are embedded in the mass of the building elements, activating them as thermal storage. TABS operates at close-to-comfort temperatures, allowing to operate geothermal heat pumps at a high efficiency. Moreover, in buildings with moderate cooling demands, passive cooling is possible at negligible energy cost. The geothermal source acts as a seasonal storage, and combined with the storage in the TABS, this enables an enhanced use of RES.
GEOTABS becomes a hybrid system by combining it with secondary heating and cooling emission and/or production systems. Because of their high thermal inertia, TABS require flexible complementary heating/cooling emission systems to swiftly react to variations in heating or cooling setpoint, ensuring thermal comfort and efficient operation at all times. On the production side, investments can become more competitive when providing a cheaper secondary supply system. This flexibility on the secondary side allows to develop hybridGEOTABS buildings for the different climates in EU, for different building typologies, for a broad spectrum of building designs and for various building energy concepts (e.g. all-electric building, NZEB etc.).
To realise the potential of this hybrid concept in reality, it does require an adequate system integration and smart control. In the hybridGEOTABS concept, the vital role of controlling the system is taken up by a Model Predictive Controller (MPC), which optimises the operational efficiency of the system in terms of energy, environmental and/or cost performance while safeguarding the indoor environmental quality (IEQ) constraints.
To allow for a wider implementation of this environmentally friendly technology in the EU market, this project tackles the major bottlenecks of the hybridGEOTABS concept. A first challenge is how to design such a hybridGEOTABS building? In order to give a fair chance for the hybridGEOTABS concept to be selected by the energy concept designer, an easy-to-use design tool is developed, that integrates the key properties of the building, the HVAC-systems and the control. A second challenge is the development of a suitable control system with MPC, that improves the energy-efficiency of the system. A semi-automated MPC toolchain is developed and MPCs are demonstrated. This leads to the third objective, that is to demonstrate the hybridGEOTABS concept in simulations and real-life buildings, and to assess its performance in terms of energy use, environment, IEQ, health, productivity and costs. The fourth objective is the establishment of a knowledge centre for hybridGEOTABS, called enerCORE, that will promote the concept and establishes the best practices, while guiding further development of the concept. The solution will support the industry and SME’s to expand their activities and strengthen competitiveness, resulting in an increased market share of energy efficient buildings.
