Thermal energy has become a strategic driver for the transformation of cities and industries towards more sustainable and efficient models. Reuse and intelligent heat management, both in industrial processes and in urban and residential environments, promotes pioneering projects in energy savings, emission reduction and ecological transition, laying the foundations for the circular economy.
In recent years, various public and private initiatives have committed to innovative solutions These technologies allow for maximum utilization of thermal energy: from the implementation of biomass-powered urban heating networks to waste heat recovery systems in factories that supply heat and hot water to entire neighborhoods. Added to this are advances in building materials, which use passive technologies to regulate interior temperature without resorting to conventional air conditioning equipment.
Industrial heat recovery and urban networks: the Michelin-Rebi case in Aranda de Duero
One of the references in Spain is Michelin and Rebi, who have integrated thermal energy recovery Wastewater from the Michelin tire factory in Aranda de Duero is used in a system designed to heat the city's homes, hospitals, nursing homes, and sports centers. This project, managed by Red Industrial de Aranda de Duero SL, recovers up to 40 GWh of heat per year thanks to the combination of high-temperature heat pumps and advanced urban infrastructure.
Until now, the heat produced in industrial processes was dissipated through cooling towers with high water consumption. The new system recovers this heat and delivers it to the urban environment at temperatures between 70 and 85 °C, also achieving a significant savings in water resources and in water treatment. Of the 40 GWh/year recovered, 33 GWh will partially eliminate the plant's traditional cooling system.
The facility also has a 3 MW photovoltaic plant through 4.200 panels and 24 inverters, whose electrical production directly feeds the heat pumps.
This synergy between industrial heat and solar energy allows a model of electrical and thermal self-consumption Low environmental impact. When solar production exceeds thermal demand, the surplus is consumed in the factory itself, minimizing the use of conventional electricity.
The not only reduces the urban carbon footprint, but it also reinforces Aranda de Duero's identity as a city committed to sustainability, in addition to opening the door to future industrial applications in other municipalities if there is institutional support.
The benefits of this system include:
- Sustainability for the industry, by reducing water, electricity, and material consumption.
- Energy innovation for Rebi, obtaining useful heat from sources that were previously wasted.
- Environmental and social improvements in the city, reducing emissions and ensuring affordable and stable heating.
This project, which combines heat recovery and solar energy, is already a replicable example of circular economy and collaboration between the industrial and energy sectors.
Heat networks in Castile and León: biomass, thermal storage, and digitalization
Another relevant initiative is the urban heat networks powered by biomass, such as the one at the University of Valladolid or the Valladolid Oeste network, promoted by SOMACYL. These infrastructures supply heating and hot water to public, residential, and industrial buildings.
The University of Valladolid network, which began operating in 2014, works with four biomass boilers totaling 19.100 kW of thermal power. The plant is equipped with a photovoltaic solar installation for self-consumption and a 3.500 cubic meter sensible heat storage system, which allows renewable energy to be stored during off-peak hours and delivered when demand increases.
In addition, the infrastructure has 12 kilometers of underground pipelines pre-insulated steel and advanced control systems, leak detection and remote management via optical fiber, allowing generation to be adapted in real time to demand and reducing thermal and electrical losses.
The latest project in the tender extends the network to the Los Viveros neighborhood and municipal facilities, replacing fossil fuels with biomass local and reducing the carbon footprint. Users benefit from greater stability and lower maintenance costs, without the need for their own boilers.
Castile and León already has , totaling 45 km of pipelines and 69.000 kW of renewable energy installed, providing service to thousands of homes and dozens of public buildings. The expansion plans are ambitious and aim to reach 239.000 kW and 180 km of network by 2030, with significant investments and local job creation.
Energy efficiency in buildings: the potential of phase change materials (PCMs)
Beyond network infrastructures, efficiency in thermal energy management also involves advances in materials and architectural solutionsIn warm areas, bricks and construction elements that integrate are being promoted. phase change materials (PCM), capable of store and release heat to maintain a stable interior temperature without additional energy consumption.
These materials take advantage of the transition from solid to liquid and vice versa to absorb excess heat during the day and slowly release it at night. Their implementation is especially useful in regions with high temperatures, allowing for reduced air conditioning usage even in extreme climates, resulting in energy savings of up to 50% and lower COâ‚‚ emissions associated with the building.
Furthermore, the use of PCM in homes and offices improves comfort and can save hundreds of kilograms of COâ‚‚ emissions per home each year. The challenge for its widespread deployment lies in improving thermal conductivity, reducing manufacturing costs, and establishing safety standards, but studies confirm its effectiveness and profitability over the medium term in different climates.
These solutions, inspired by traditional architecture but optimized with current technologies, demonstrate that energy efficiency can also be achieved from the building's own design by combining constructive wisdom, innovation and sustainability.
