Perfect air conditioning for one of Europe’s most modern theatresPerfect air conditioning for one of Europe’s most modern theatres

Jukka Juottonen

Global Industry Segment Manager for HVAC at ABB

The Chemnitz Opera House attracts well over 90,000 visitors a year to enjoy opera, ballet and musical performances. Automation systems and specialized HVAC drives play a key role behind the scenes. The result is that both the performers and audience experience perfect air-conditioned comfort delivered with maximum energy efficiency.

Keywords: Chemnitz Opera House, Building Renovation, Energy Performance Contracting, Building Automation Systems

Figure 1. The Chemnitz Opera House is an architectural and cultural gem. Copyright: Dieter Wuschanski / The Chemnitz Theatres.

One of the most well-known cultural institutions in Germany, the Opera House was first opened in 1909. It was destroyed during the Second World War and reopened in 1951. Following extensive reconstruction work on the building in 1992, Chemnitz Opera House is regarded as one of Europe’s most modern theatres. It has recently been modernized to further improve ventilation and air conditioning for the 180 or so performances that take place every year while reducing energy consumption to meet current best practice.

The peak of energy efficient performance

The main opera house as well as the theatre were completely modernized as part of an energy saving contract between the city of Chemnitz, the theatre and the contractor WISAG Energy Management. The project covered the ventilation and air conditioning equipment, hot water systems and lighting. (Figure 2)

Figure 2. All controls are operated via the touch screen of the CP430 control panel.

An automation system was installed to provide optimized control and energy management for the HVAC equipment and hot water circuit. The system comprises three ABB AC500 PLCs (Programmable Logic Controllers) as well as two specialized ACH550 low voltage HVAC drives, together with fuses and relays.

A refinance model for energy saving

The modernization of its outdated heating and ventilation systems has long been on the agenda of the Chemnitz Municipal Theatre. The concept of energy performance contracting based on guaranteed savings over a specified period offered the opportunity to finance the conversion work. WISAG emerged as the most economical bidder and was entrusted with the project.

The contractor invested almost 930,000 euros in new, energy-efficient systems for the opera house and the playhouse. The aim was to reduce the cost of district heating by 35 percent and electricity by 32 percent. There is also a guarantee in place that the energy costs will be reduced by 121,670 euros a year compared to the reference year of 2013.

Comprehensive modernization

As part of the renovation work, the ventilation, air conditioning and hot water production in both the opera house and playhouse were completely modernized together with the installation of cutting edge lighting technology. The new ventilation systems are equipped with heat recovery systems so that in winter unused heat is reused rather than being exhausted into the atmosphere.

The new energy technology systems were installed in a six-week break in the summer of 2015. "Everything really had to be fitted at once," says Jens Israel, project manager for technology at WISAG energy management.

Specialized HVAC drives cut energy consumption by 50 percent

Two PLCs (programmable logic controllers) execute the control functions in the opera house, processing hundreds of I/Os (inputs/outputs) from other control units, substations and the drives. Another PLC is installed in the theatre. Communication between the controls in the opera house and the theatre is handled by one central unit which collects the information, evaluates it and transmits the appropriate response to the relevant panels and the building automation and control system. (Figures 3 and 4).

Figure 3. The AC500 PLC in the boiler room is responsible for all communications in the opera house.

Figure 4. The PLC in the pipe cellar regulates six heating circuits of a large and complex ventilation system.

The central unit also communicates with the two specialized HVAC drives integrated into the building automation system, which control the pumps in the district heating station. Rather than requiring the electric motors that run the pumps to run constantly at full speed, the drives facilitate stepless speed control based on the actual demand. Reducing the motor speed by 20 percent lowers the power required by up to 50 percent. Typically, HVAC drives (Figure 5) offer a return on investment within months, based on energy savings alone.

Figure 5. Two HVAC ACH550 drives regulate the pumping of the substation.

A second central unit controls the heating as well as the large and complex ventilation systems of the opera house. The environment is adjusted according to the outdoor temperature, indoor conditions and several time-based programs.

A model for other municipal organizations

The modernization of power engineering at the opera and the theatre went smoothly and to the satisfaction of all parties "on the stage". Most importantly, the targeted energy savings have been achieved. With the Chemnitz Municipal Theatre as a pilot project, it is now hoped that the Saxony State Ministry for Environment and Agriculture will roll the concept out to other municipal organizations.