Content added to your bookmarks in MyHoval

File added to your bookmarks in MyHoval

There has been an error while adding Content to your bookmarks in MyHoval

Heating at a height of 170 metres – Hoval's solution for the Danube Tower in Vienna

Heating at a height of 170 metres – Hoval's solution for the Danube Tower in Vienna

The Danube Tower Vienna, the tallest building in Austria, presents itself in new splendour after a complete renovation. The Viennese landmark also received a heating solution from Hoval, which scores with an optimal price-performance ratio.

  • Other building
  • Renovation
  • Oil/Gas

420,000 visitors per year. Six marriage proposals a week. With a total length of 252 metres from base to top, the Danube Tower Vienna, which opened in 1964, is the tallest building in Austria – and a tourist magnet. The 170-metre-high restaurant and 160-metre-high tower café were completely modernised in 2018, as were other areas on the ground floor. The opening of the large new Donaubräu beer pub in February 2019 marked the completion of the conversion and renovation work.

Way to the top with a new heating system

Even before this work began, the renewal of the tower technology started in 2017. Among other things, a new solution from Hoval replaced the aging heating system. Due to the high efficiency of the Hoval system, the new standards for pollutant limits are also complied with. Two Max-3 gas boilers were installed by the Hoval partner installer during the current autumn operation.

They now supply the tower and also supply the higher capacity needed for the new catering areas. While the Danube Tower with all buildings previously had a heating power requirement of 450 to 500 kW, it is now 650 to 700 kW.

The biggest challenge in the planning of the system, however, arose from the height of the areas to be heated at the very top of the tower. Hoval Area Manager Christian Böhm, who worked out the technical solution together with the partner, explains:

"For every ten metres of altitude, the pressure is reduced by 1 bar. A pressure of 18 bar is therefore required in the boiler room in order to ensure the required 165.1 bar pressure on the central floor of the tower at a height of 5 metres."

Since standard boilers are not designed for such high pressure, Hoval opted for system separation. The two Max-3 gas boilers deliver the required power with 350 KW each. The energy is transferred to a separate circuit via a heat exchanger. At the same time, the two-boiler solution ensures the reliability and flexibility in operation desired by the Danube Tower.

State-of-the-art heating technology that rotates with you

Another main theme in the design of the new heating system was the two revolving stages of the tower restaurant and the tower café. Here, a plinth heating system with warm air ensures that visitors can enjoy the view over Vienna even in winter. The air is directed from the center of the tower to the rotating air ducts in the floor with the help of a new brush technology.

To heat the air, a second heat exchanger is installed at the top of the tower. Since this is always accompanied by a low temperature loss, it is a particular advantage that the robust Max-3 boilers can deliver a consistently high temperature. Christian Böhm:
At the top of the tower, the warm air must be heated to 80°C on cold days. To achieve this, we bring the heating water in the boiler to around 100°C.

From concept to maintenance

Hoval accompanied the project for the extraordinary building from the calculation of the system to the coordination with the partner installer during the execution phase. Claudia Pich, company spokeswoman for the Danube Tower, is very satisfied:

The heating system works smoothly. Hoval met all our expectations.

Since commissioning in October 2017, Hoval has been responsible for boiler management and maintenance. The TopTronic E control system, which regulates the use of the double boilers as required, has proven its worth here. Via an online connection, the customer service technicians have the possibility of remote access to the system. And Hoval has even set up a small warehouse with spare parts especially for the Danube Tower. After all, the Viennese landmark should be optimally supplied.