Acting instead of talking: How buildings help protect the climate

Glass facades promise views and insights. The downside: costly air conditioning in summer and a lot of heating energy in winter. The intelligent shading systems from SL-SunTech provide a remedy here. The control of shading via a SIMATIC S7-1200 considerably reduces energy and CO₂ costs for air conditioning and heating.

For Nacettin Uludasdemir, owner of SL-SunTech, buildings are one of the fields where climate protection has not yet been sufficiently considered and implemented. "Often, only the insulation of the building envelope or the change of heating from fossil fuels to sustainable energy sources are mentioned when it comes to energy consumption and CO₂ footprint." Yet, there are many other variables, especially in office buildings: "With a normal triple-glazed window, in summer around 225 kWh of energy is brought into the building per square meter of window area by solar radiation, and you have to dissipate the excess heat via an air conditioning system. In winter, it's the other way around: then we want to use the solar radiation to reduce the heating load. That's where our intelligent shading solution can help." The system from SL-SunTech is equally sustainable in both a retrofit and a new build. In many cases, the solution can be easily retrofitted into existing shading systems, and the cost typically pays for itself in the first summer, says Uludasdemir: "Many owners and operators aren't even aware of the potential there is in their buildings."

Retrofit with modern automation

Uludasdemir shows how such a retrofit works during a tour of an office building in Neuss, which SL-SunTech recently equipped with a new sun protection control center. For this purpose, a total of 1,150 external venetian blind systems with a slat area of around 3,000 m² were integrated into a new sun protection control center on the 10 facades of the nine-story building. In addition, SL-SunTech installed a new sensor package for intelligent control of the shading. The core of the automation is a versatile SIMATIC S7-1200 controller, which is controlled via a SIMATIC HMI KTP400 Basic Panel with touch operation. Nacettin Uludasdemir deliberately chose this solution. In addition to its robustness and reliability, the openness of the SIMATIC platform is a decisive argument for him: "Many control centers are based on proprietary systems that are difficult for the operator to maintain. SIMATIC systems, on the other hand, can be flexibly expanded at any time, even retroactively, of course." The application software is stored on the SD card of the control system. "We provide users with a solution that really belongs to them - unlike other systems, with our concept they are independent of a special project partner. In this way, we give our customers a piece of investment and future security."

Investment protection through intelligent control

The openness of the system also pays off in lower operating costs, explains Nacettin Uludasdemir: "Before, there were no safety commands for this building to retract all equipment in the event of wind or storm. That can quickly become very expensive in a thunderstorm or storm event." The new control center is connected to a weather station that has no moving parts. Part of this weather station is a wind sensor, so when the weather is right, the external venetian blinds can be retracted quickly and centrally. At a preset time or at dusk, all blinds are moved to the open position centrally, so that they are less exposed to wind and weather. When outside temperatures are warm and light conditions are good, the central controller uses the "Temperature-dependent light-time combination" operating mode to extend the shading once in the morning; when outside temperatures are cold, the external venetian blind systems remain in the open position. "In this way, we achieve that in summer the air conditioning system is relieved by sensible shading and in winter the heating system is supported by solar gains," explains Uludasdemir. In addition, the users of the offices have the option of regulating the shading individually at any time - "but with an intelligent control system, this is necessary much less often, which also contributes to a longer service life of the shading systems." Because, the expert continues, often the objects work with the operating mode "automatic". This leads to the fact that with a frequent change between sun and clouds the Raffstores drive up and down several times throughout the day. Many users feel disturbed by this, so that the automatic operating mode, which is valuable in itself, is deactivated. The SL-SunTech system can also determine the position of the sun by means of azimuth and elevation and align the slats of the external venetian blinds according to the position of the sun by means of a corresponding automatic sun tracking system. This means that less artificial lighting is required if there is too much shade. All in all, this results in significant economic advantages compared to a costly sun tracking automatic system using SMI motors with EIB/KNX or expensive external venetian blinds with daylight technology.

Openness also convinces operators

SL-SunTech modernized the building in Neuss within just four weeks and handed over the plant to the operator - even though there were some unforeseen challenges in the process: For example, there was only patchy documentation of the existing systems, and the existing floor control system had to be completely redesigned. For this purpose, SL-SunTech set up a simulation system with the SIMATIC S7-1200 controller in its own workshop. Not least, due to this good preparatory work, a large part of the existing hardware and the weather station could be transferred to the new controller without any problems. The result also positively surprised the building operator in particular: "The before and after comparison were a real “aha” experience for our client," says Uludasdemir proudly.

For upcoming projects, SL-SunTech is already working on the next level of intelligent building shading: "With the SIMATIC S7-1200, we can integrate not only additional sensors, but also external information and services into our solutions. For example, we can detect failed sensors via a plausibility check and prevent a possible damage situation during weather events. In the next step, we can use the integration of weather data to anticipate an impending drop in temperature or a storm event, for example, and adjust our shading systems in good time." Such an intelligent shading system can have a significant impact on a building's energy consumption, says Uludasdemir: "With an automatic sunshade, we can reduce the energy input from the sun by 70% in summer." That means less air conditioning, less energy consumption, less CO₂ emissions - simply via intelligent automation of the shading system as a retrofit or in new construction. Or as Nacettin Uludasdemir says: "Doing climate protection instead of just talking about it."

With automatic sun protection, we can reduce energy input by 70% in summer. That means less air conditioning, less energy consumption, less CO₂ emissions.
Nacettin Uludasdemir, Owner, SL-SunTech