Ensuring efficient renewable energy supply for multifamily residential buildings

Driven by the clear urgency to stem climate change, scientists are researching different ways to transform the global energy sector from fossil-based to zero-carbon. For this energy transition process to be successful, ensuring renewable energy supply for buildings is crucial.

With the support of the EU-funded TRI-HP project, a team of researchers is working to provide tailored energy solutions for buildings in Europe. The buildings in question are multifamily residential buildings with a net-zero energy concept. “Almost 50 % of the final energy consumption in the European Union is used for heating and cooling,” observes project manager Dr Daniel Carbonell of SPF Institute for Solar Technology, Switzerland, in a YouTube video. He goes on to add that 80 % of that amount is used in buildings, highlighting the need for renewable energy solutions if Europe is to decarbonise its energy supply systems. The project’s goal, as described by Dr Carbonell in the same video, “is to develop flexible, energy-efficient and affordable trigeneration systems able to provide heating, cooling and electricity.”The project is developing systems based on electrically driven natural refrigerant heat pumps that are combined with photovoltaics. The use of natural refrigerants such as CO2 and propane will overcome the environmental and safety issues attached to synthetic refrigerants. “One of the main innovations of the project is the use of the super-cooling method combined with the solar ice-slurry concept to provide heating demands in buildings,” explains Dr Carbonell. Ice-repellent coatings will be employed to build the heat exchangers used as supercoolers to ensure ice-free surfaces. Another innovative concept is the dual ground/air source system that will make it possible to use ground and air as heat sources or sinks based on the best source available at different times in the day.

The use of three heat sources, namely solar, ground and ambient air, will endow the systems being developed with valuable flexibility. The project’s innovations have the potential to lower installation costs by up to 15 % compared with current heat pump technologies. They also aim to reduce greenhouse gas emissions from gas boilers and air chillers by an impressive 75 %.

The CO2 and propane heat pumps that the TRI-HP (Trigeneration systems based on heat pumps with natural refrigerants and multiple renewable sources.) project is developing will be tested in the lab. “A follow-up step will be to demonstrate these technologies in real residential buildings and to extend the development of the super-cooling ice-slurry method to the industry,” states Dr Carbonell. To be able to cover a significant proportion of Europe’s multifamily residential buildings, the newly developed technologies will be used in both new and renovated buildings.