Heat pumps are booming but not all properties have space to accommodate the external air unit needed for an air-to-water heat pump.
Where space is limited, new solar thermal façade panels could provide a noiseless and space-saving alternative, as well as an attractive architectural feature.
As part of its ongoing TABSOLAR III research project, the Fraunhofer Institute for Solar Energy Systems ISE is developing and testing its TABSOLAR panels.
Thepanels feature brand new solar thermal components made from ultra-high performance concrete (UHPC). Available in a glazed or unglazed finish, they can be used to create an aesthetic architectural façade.
Each panel is interspersed with channels containing a solar fluid, which absorbs the heat from the sun’s radiation and ambient air.
This heat is then transferred via a heat exchanger into the heat pump circuit.
The design of the channel structures is created using the bionic FracTher process developed by Fraunhofer ISE, which produces a multiple branched (or fractal) pattern similar to the veins found in leaves or the human body.
Using this process, it is possible to create an evenly distributed network of channels across almost any shaped panel, which ensures uniform flow distribution and also a lower energy consumption rate for the pump.
The panels themselves are made of ultra-high performance concrete using a membrane vacuum-forming process that is being further developed in cooperation with several industry and research partners as part of the TABSOLAR III project.
As low-temperature heat sources, the TABSOLAR panels have the potential to provide a noiseless and attractive alternative to external air units for air-to-water heat pumps, according to Dr. Michael Herman, coordinator for the TABSOLAR III project at Fraunhofer ISE.
“Our simulations suggest that both new builds and older retrofitted building stock would have sufficient façade space for this purpose,” he said.
The prefabricated TABSOLAR panels have been developed for suspended rear-ventilated façades (VHF), but there is potential to adapt the concept for composite exterior insulation and finish systems or sandwich wall systems in future. Moreover, the panels from the TABSOLAR® Heat & Cool range can be installed inside buildings as thermally activated building systems (TABS) for heating/cooling (including alongside conventional concrete core activation).
“We have pooled expertise from the relevant solar technology and construction sectors to develop an innovative and architecturally attractive solution which we hope will further the energy transition in the building industry,” he said.
New software tools have also been developed for the planning phase, including an augmented reality app for visualizing the façades in-situ and an online configuration tool to aid the design process.
Plans are in place to ensure the technology can be integrated intoBuilding Information Modeling (BIM) processes. As the next step in the development process, the complete solution will now be prototyped in a demonstration façade and undergo practical testing and monitoring.