Hot days, hot nights, sweating Viennese: The heat days are increasing due to climate change, temperatures regularly above 30 degrees are more the rule than the exception – and call for cooling off. Accordingly, Wien Energie’s district cooling system has been in use for weeks – because at temperatures from 35 degrees Celsius, around three times as much cooling capacity is required as on average summer days. Via 28 kilometers of district cooling lines, Wien Energie cools around 190 buildings in a climate-friendly manner – and the number is growing all the time. District cooling capacity is expected to almost double by 2030.
Wien Energie: EUR 90 million for expansion of district cooling
Wien Energie is already cooling an area of four million square meters in a climate-friendly manner – the district cooling supplies, for example, the AKH, the MAK, the university and the parliament, but also numerous hotels and several hundred new apartments, for example in the Nordbahnviertel or around the main station. By 2030, Wien Energie wants to cool an area of 7.3 million square meters with district cooling, which is larger than the area of the Vienna Prater. But first the next stage of expansion is pending – and here the year 2024 is of particular importance: By autumn of the coming year – and thus a year earlier than originally planned – the district cooling connection of the ring road will be achieved and many of the important buildings will be connected to the district cooling network connected.
“The need for cooling has been increasing for years. In order to ensure climate-friendly cooling, we are continuously expanding our district cooling network. The realization of the district cooling ring around the city center of Vienna is a major milestone and enables the entire city center of Vienna to be supplied with climate-friendly district cooling. We will invest around 90 million euros in environmentally friendly cooling technology by 2027,” says Michael Strebl, CEO of Wien Energie. The increase in district cooling customers is 10 to 15 percent every year.
Turn old into cold: Waste heat becomes district cooling
Wien Energie is currently covering the high demand for cooling via seven high-performance and energy-efficient district cooling centres. This includes, for example, a control center in the Spittelau waste incineration plant. The waste incineration plant is in use all year round and basically generates district heating, which supplies large parts of Vienna with heat for heating and hot water in winter. In summer, however, significantly less heat is required in the city, which is why Wien Energie uses excess district heating to generate district cooling, among other things. In addition to electric chillers, absorption machines are used for the most part, which are operated with district heating instead of electricity and thereby generate cold. The highly efficient chillers in the district cooling centers generate cold in the form of cold water.
The central generation saves 70 percent of energy and 50 percent of CO2 compared to conventional air conditioning. The water, which has been cooled to about five to six degrees Celsius, is transported directly to the customers via a separate district cooling network and distributed there via the in-house cooling systems in the buildings.
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New headquarters at the MedUni Campus
In total, Wien Energie currently has 22 cooling locations in operation, including the seven district cooling centers with district cooling network and 15 decentralized cooling solutions directly at customers. An eighth district cooling center is currently being built at the MedUni Campus Mariannengasse. The energy service provider is building the city’s eighth high-performance district cooling center here in Vienna Alsergrund and is investing around 20 million euros in it.
The largest district cooling consumer will be the MedUni Campus itself, whose 35,000 square meter area will be cooled by the district cooling center. The remaining cooling capacity flows into the district cooling network, which Wien Energie is constantly expanding. An important step to further expand the district cooling network in the city center.
Michael Strebl: “The climate crisis does not stop at Vienna! In order to ensure sustainable cooling, we are relying on the expansion of district cooling. The district cooling center on the MedUni Campus Mariannengasse is an important milestone in this regard. With the modern and future-oriented technology, which, among other things, turns heat into cold, we will be able to generate cold very efficiently in Alsergrund from 2025 and save a total of 1,000 tons of CO2 per year. That corresponds to the CO2 binding power of 80,000 trees! Our plan is to connect the network between the city center and around Spittelau via this new headquarters.”
Wien Energie is planning the city’s first deep geothermal system by 2026