In addition to greenhouse emissions, the final energy consumption in buildings also continues to increase. As a result, it is essential to seek solutions to construct and rehabilitate buildings by making them more efficient.
A research group, including Lorenzo Olivieri from the School of Architecture at Universidad Politécnica de Madrid (UPM), has conducted a research to create a new radiant element for facades of high thermal energy storage with the help of phase change materials.
These materials enable utilization of the latent heat absorbed and liberated during the phase transition from solid to liquid. Using these materials, a considerable amount of thermal energy can be stored in a lower volume than sensible heat storage.
The trend in the construction industry is quite different from the Sustainable Development Scenario specified by the International Energy Agency that outlines a significant transformation of the global energy system, demonstrating how the world can shift course to deliver on the three main energy-related SDGs at the same time.
There is an increase in enthusiasm to use more efficient building materials, new systems, and new technologies to realize the goals defined by energy policies; however, they are still inadequate.
The goal is to achieve net-zero energy buildings that, by combining an ultra-efficient design of the envelope with renewable energies, can locally produce the same amount of energy they demand over a year.
Lorenzo Olivieri, Researcher, Group of Renewable Distributed Generation and Intelligent Control (GEDIRCI), UPM
Generally, the vast majority of the final energy used in European residential buildings accounts for heat systems (65%) and domestic hot water generation (15%); other usages such as appliances, air conditioning, and lighting are less demanding. To continue, 80% of the final housing energy is for heat production. Thus, the search for solutions that can offer thermal comfort with little external energy is important to realize zero-energy buildings.
A research team from Instituto de Ciencias de la Construcción Eduardo Torroja (IETcc) at Universitat de Lleida together with the Instituto Español del Cemento y sus Aplicaciones and INDAGSA company and the partnership of various universities (Jaume I, Barcelona and Politécnica de Madrid) has performed the Inphase project which is concentrated on the development of a new radiant element of high thermal storage by using phase-change materials (PCM).
During the first phase of the project, more than 10 commercial phase-change materials were characterized to identify the most appropriate option for the radiant wall. A comprehensive laboratory-scale characterization was performed in view of the following properties: specific heat capacity, temperature of phase change, thermal stability, and conductivity.
The next challenge was to develop a mortar using PCM to directly add microencapsulated PCM inside the mortar matrix with the intention of using it for the traditional production processes of precast elements. Therefore, scientists tested the thermal properties of different cement mortars with PCM, changing the type and amount of elements in the mixture.
The results demonstrated that the best thermal properties are achieved from silica aggregates and antifoam additives, and this enabled scientists to identify the optimum formulation of a PCM-added mortar for building components.
“This project resulted in an innovative solution in terms of design and construction for residential building facades based on adding phase change materials in precast concrete walls. In conclusion, this result is a suitable solution for sustainable building design,” Olivieri concludes.