Following the start of the economic boom in the late 1940s, construc­tion activity across Europe surged. However, the huge demand for afford­able housing meant the focus during this time was on building as rapidly as possible, with little consid­er­a­tion given to the energy balance. And this is now a problem. Since much of today’s housing stock dates back to between the 1950s and 1970s, 75 percent of the build­ings in the Euro­pean Union (EU) are not rated as energy effi­cient. According to the EU Building Direc­tive, this needs to change. By 2035, the average primary energy consump­tion of existing resi­den­tial build­ings must be reduced by 22 percent. The ulti­mate goal is for all build­ings to be climate neutral by 2050. However, energy-related refur­bish­ments are both costly and time-consuming, resulting in consid­er­able chal­lenges for resi­dents during the construc­tion phase. So what can be done to change this?

The INFINITE project: system­atic refur­bish­ment

For the past five years, Fabrizio Miorin has been working hard on answers to this ques­tion. Miorin is the head of research and devel­op­ment at Vortice, an Italian manu­fac­turer of venti­lation systems and a contrib­utor to the EU-funded INFINITE project. “Together with 20 part­ners from eight coun­tries, including manu­fac­turers of prefab­ri­cated houses, construc­tion compa­nies and univer­si­ties, we are devel­oping solu­tions to improve the energy balance of houses by refur­bishing their facades without any signif­i­cant inter­ven­tion.” The aim of the project is to reduce refur­bish­ment costs by up to 50 percent, shorten construc­tion time by 54 percent and extend the service life of the refur­bished build­ings by an addi­tional 50 years.

The idea is to use indus­tri­ally prefab­ri­cated facade elements made from sustain­able mate­rials that can be easily attached to the existing wall from outside. A special feature is the devel­op­ment of modules that can be inte­grated into the facade elements using the plug and play prin­ciple, enabling them to perform other func­tions in addi­tion to insu­la­tion. These include, for example, solar cells to produce elec­tricity, plants to green the facades, smart windows that darken auto­mat­i­cally in sunlight and even a venti­lation, air condi­tioning and heating system for the homes. This is exactly where Vortice can contribute its exper­tise. The task of Miorin and his team of engi­neers was to develop a venti­lation system that is narrow enough to fit the facade elements, consumes little energy and, above all, oper­ates quietly. “The aim is that the venti­lation system should not disturb resi­dents,” says Miorin.

How the Vortice solu­tion works

Exhaust air (from WC and kitchen)

Supply air (to dwelling rooms)

Fresh air (from external envi­ron­ment)

Exhaust air (after having recov­ered its thermal energy)

Return air (from living room and bedrooms to be recir­cu­lated)

Elec­tronic board that inter­acts with room remote control

Exhaust fan

Heat recovery exchanger (connected to hydraulic heat pump circuit)

Supply fan

Elec­trical connec­tion

(Image | Vortice)

Inte­grated venti­lation

Devel­oping a stan­dard­ized solu­tion that meets these require­ments is far from simple because every facade is a little different. Some build­ings have balconies whereas others do not. There may be differ­ences in the arrange­ment and size of the windows and also signif­i­cant vari­a­tions in the size of homes. “We analyzed the build­ings in Europe in detail. In Eastern Europe, homes tend to be smaller than in the West. We need a solu­tion that works for all houses. That is why the thermal unit is dimen­sioned for homes of 50 square meters. This gives us maximum flex­i­bility,” explains Miorin. In the case of larger homes, addi­tional facade elements are equipped with climate-control tech­nology.

In collab­o­ra­tion with other project part­ners, ­Miorin and his team devel­oped a concept that includes a heat pump to centrally produce heating or cooling for the entire building as required. The venti­lation units supplied by Vortice distribute this to the indi­vidual apart­ments. However, they actu­ally do a lot more. “We extract the thermal energy from the exhaust air and return it to the apart­ments via a highly effi­cient heat exchanger connected to the heat pump circuit. At the same time, we supply fresh air to all rooms,” explains Miorin.

Two INFINITE pilot projects in Europe

In this way, the system saves more energy. Miorin needed two fans to imple­ment this solu­tion: One removes stale air from the rooms, while the other distrib­utes fresh air and heat. When it came to choosing a manu­fac­turer, the engi­neer did not have to think about it for too long: “We’ve been working with ebm-papst for many years. Partic­u­larly in projects like this, it’s impor­tant to have a proven expert to supply reli­able and effi­cient prod­ucts. And the collab­o­ra­tion is also very good at the personal level.”

Quiet and effi­cient RadiCal fans

Miorin’s inquiry landed on the desk of Carlo Paroni, Team Leader Air Condi­tioning & Venti­lation at ebm-papst Italy. Decen­tral­ized venti­lation systems are nothing new for Paroni because ebm-papst has devel­oped axial and centrifugal fans for precisely this kind of appli­ca­tion. What was new to him, however, was the way in which the venti­lation systems were to be used: “This is an exciting and inno­v­a­tive project that offers great poten­tial for saving energy in existing building stock. It’s a very good fit with our own corpo­rate values.”

 “Vari­able control of the fans means that our system can operate very precisely.“ Fabrizio Miorin, head of research and devel­op­ment at Vortice

Vortice chose two RadiCal fans for its system, which satisfy all the require­ments that were impor­tant to Miorin: They are compact, energy-effi­cient, vari­able thanks to EC tech­nology and extremely quiet, even at full power. Miorin explains: “Vari­able control of the fans means that our system can operate very precisely and deliver the output that is actu­ally required.” Of course, energy effi­ciency is essen­tial in a project that is intended to cut costs and protect the climate.

The reality check

Vortice’s venti­lation solu­tion still has to prove itself under real condi­tions on facades requiring refur­bish­ment. To date, the facade elements have been tested in two pilot projects in Italy and Slovenia. The first analyses and find­ings are expected in 2026. If all goes well, it will soon be possible to install the prefab­ri­cated facade elements in many other build­ings across Europe, thus enhancing effi­ciency and comfort. There are more than enough reasons to accel­erate this process.

At present, the average rate of energy-related refur­bish­ment in the EU is only about one percent. Miorin is convinced that the solu­tion deliv­ered by the INFINITE project can make an impor­tant contri­bu­tion to climate protec­tion. And he is already thinking about the next devel­op­ment: “I believe that decen­tral­ized heat gener­a­tion is conceiv­able in place of a central heat pump.”