Number 4 Doctor Marañón Street in downtown Cadiz is just another example of the Spanish rationalist architecture of the mid-twentieth century. However, in four years it will be one of the first residential buildings in Europe located in a warm climate zone to be outfitted with new air conditioning technologies designed to keep carbon dioxide emissions and energy consumption at close to zero.
This will be necessary with what’s coming for southern Europe in 2050: nights with highs of 40°C, heat waves of more than 10 days, and up to a four degree increase in average temperatures, according to projections from the World Meteorological Organization. “The data is scary,” says Francisco José Sánchez de la Flor, who has doctorate in industrial engineering from the University of Cadiz (UCA).
In the European post-crisis scenario, we need more building rehabilitation than construction Francisco José Sánchez de la Flor, project engineer
He and his team, made up of a dozen researchers from the UCA’s thermal engineering group, are already working on the project that aims to turn the building into an example of warm weather adaptation. They are not alone in their efforts, the team is part of the ReCO2ST project, a pioneer in Europe and responsible for the European Union’s Horizon 2020 program that investigates the energy efficiency of buildings.
In addition to Cadiz, a cooling-focused project, three other constructions will serve as a model for temperate and cold climates with heating systems: one in Frederikshavn (Denmark), one in Lausanne (Switzerland) and one in London. In total, up to 18 partners from nine European countries are working together, each providing its technological solutions for building heating and cooling systems.
Despite the different climatic conditions for each building, the four cases have the same goal, summarized by Sánchez himself: “We want to show that there are new technologies in experimentation phases that are already feasible and profitable, at a technical and economic level, to the application of rehabilitating buildings.” Hence the European guidelines were very concrete: the project must renovate already existing buildings and must involve public–private collaboration.
“The intention is that the test be as practical and realistic as possible. In the European post-crisis scenario, we need more rehabilitation than construction,” acknowledges Sánchez de la Flor.
Smart buildings It will be necessary with the extreme heat that’s coming for southern Europe in 2050
The University of Cadiz participates in its city’s project, together with the municipal housing companies, Procasa and Acciona. In addition, the Cadiz building will have a twist, as it will be used for social housing. “We know that poverty and energy vulnerability mean families with few resources see their health affected by poor heating and cooling. Implementing social housing makes our project unique,” says the UCA lecturer.
The entire project is already a challenge, says Sánchez de la Flor. “When you have a new building you can control all the design parameters from zero, but here you have to adapt to the constraints imposed by an existing building.” The renovation is of a structure that is more than 60 years old and which is protected for its historic and architectural interest. The scientists, in collaboration with the architects from Procasa and Acciona, have proposed two fundamental solutions: the covering of the facade and the roof with a second, ventilated, and evaporative skin and the creation of inner cross ventilation.
The first solution is based on the use of two existing technologies. They will cover the whole exterior with slabs separated from the facade by an air chamber, as is already done in many buildings. In addition, the engineers will put a water channel in the space, “a technique that was used for the first time at the Seville Expo in 1992 to create microclimates, by researchers from the University of Seville,” the Cadiz professor explains. In addition, the inner chamber of the facade will open or close, depending on the temperatures. “For example, in winter it will be closed so as to not let the heat escape from the building.”
The union of both techniques has not been simple, as Sanchez de la Flor writes: “There have been many years of studies and trials between the universities of Cadiz and Seville. We were able to demonstrate that it works in an experimental situation and it will now be applied for the first time to a residential building.” This second smart skin will add cross ventilation to regulate the entrance of outside air to “take advantage of favorable external conditions,” explains Sánchez de la Flor. The system will activate only when outside temperatures are cooler.
These systems will be necessary in the future and, increasingly, more profitable Francisco José Sánchez de la Flor, project engineer
A set of sensors will monitor the smart building’s 1,077 square meters and transmit the data to a central computer that will decide when to activate the ventilation. Depending on conditions, the system will be capable of bringing down the interior temperature of the building up to five degrees on extremely hot days. All this will lead to energy savings and reductions in carbon dioxide emissions. The savings that can be achieved will repay the investment in less than 15 years.
“We want to show that the system works, that it is applicable, and that maintenance is straight forward and low-level,” adds the professor. The project (with a total cost of €8.5 million) must show results in no more than four years. After that time, the scientists participating in the project will present the results of combining the technologies, with the idea of popularizing them .
The designers chose a building from the mid-twentieth century, instead of one of Cadiz’s more historic buildings, because most European constructions are from that time. “If Europe has to reduce its carbon dioxide emissions, it has to look at existing buildings because energy consumption in those generates 40% of total emissions. The idea is that what is done here can be replicated in buildings throughout the Mediterranean basin.” Sanchez says as he walks around the building where construction has not yet begun.
While architects and scientists are already working hand in hand, time is running out, as climate change conditions will become increasingly extreme. the University of Cadiz understands “the enormous challenge” they are taking on. “All these systems will be necessary in the future and, increasingly, more profitable. Unfortunately, climate change will make summers increasingly long and intense and this form of air conditioning will become increasingly necessary in Europe, not only in areas with warm climates,” says Sánchez de la Flor.
English version by Debora Almeida.