Pictures of the Future    Spring 2006

Entering the Comfort Zone

Together with the Technical University of Munich and other partners, Siemens is developing a unique system that simulates air-conditioning comfort—interactively and in real time.

Can you have a hot head and cold feet at the same time? Test dummies in aircraft cabins indicate that the answer is yes. Will that make you feel uncomfortable? Absolutely. Although a dummy’s face can be blasted with hot air from a ventilator nozzle, its feet as cold as blocks of ice. "Achieving exactly the right comfort level with air conditioning is a highly complex science," explains Dr. Christoph van Treeck. "Why is it that we can freeze at a room temperature of 23 °C, yet still be sweating at 17 °C, like the driver who has the air conditioning on but is still getting the full force of the sun through a sunroof?"

Dressman, a new type of test dummy developed by the Fraunhofer Institute of Building Physics (IBP) near Munich, may have the answers. Part of a research project know as ComfSim, Dressman also involves the Technical University of Munich (TUM), engineering consultants Müller-BBM, the Leibniz Computing Center, and Siemens Corporate Technology (CT). "The goal of the project is to develop a new air-conditioning comfort model to simulate a whole range of scenarios in real time, interactively and in 3D," explains van Treeck, project manager for ComfSim at TUM’s Department of Computing for Civil Engineering. Each partner has a specific area of responsibility. IBP, for example, analyzes the impact of air currents, temperature, clothing and humidity on comfort levels in buildings, aircraft and its own flight lab, which features a section of a real plane. This involves the use of special sensors attached to Dressman, which measure a range of parameters, thereby simulating the sensitivity of human skin.

"Conventional models only apply to the body as a whole and don’t take local differences such as cold feet and a warm head into account. With the new setup, however, we can determine the comfort of individual parts of the body," says van Treeck. "On the basis of the models developed by IBP, our team programs the algorithms for our simulation model. Engineering consultants at Müller-BBM then provide us with a set of realistic boundary conditions, such as how the surface temperature of components changes through the day." ComfSim has funding from the Bavarian Research Foundation.

Huge Data Volumes. As of mid-2006, a new Federal Supercomputer at the Leibniz Computing Center will begin crunching the huge data volumes involved in the simulations generated by the ComfSim project. "The new mainframe from Silicon Graphics is around 30 times faster than the current HITACHI SR-8000," explains van Treeck. "That makes it one of the ten fastest computers in the world." It will initially be able to process 33 trillion floating-point operations per second (33 Tflops) and will reach 69 Tflops once it reaches full capacity in 2007. For the first time ever, it will be possible to carry out complex simulations of air-conditioning comfort in real time and to modify the scenario interactively. This will bring major benefits for the construction industry as well as manufacturers of cars, aircraft and rail vehicles. "Thanks to ComfSim, engineers, designers and architects will already have access to simulations during the planning and design phase. This will help eradicate errors and therefore significantly enhance the reliability of the draft plans," explains Barbara Neuhierl, project manager for ComfSim at Siemens CT.

Airflow simulations have long been a standard tool in the design of heating, air-conditioning and ventilation systems. "Today, simulation is common practice in many areas of design," Neuhierl confirms. "But it’s never been possible before to move things around onscreen—a desk in a virtual office, for example—to see what effect this has on air currents and to evaluate the results at the same time. With ComfSim, you get real-time simulation with interactive capability. And that’s unique."

What are the benefits for users? "At the press of a button ComfSim can generate the kinds of simulations that it takes days or even weeks to produce with conventional methods," says Neuhierl. "Speeding up operations and reducing development times means that industry can produce more efficiently and earn more money."

"When tenders are submitted in the shipbuilding industry—say, for the ventilation system in the engine room of a ferry—design engineers only have seven days to put together an offer," says van Treeck. "As a rule, it’s impossible to create a simulation model within a week." Yet planning errors can result in huge costs by the end of the development phase. "With ComfSim, engineers have a tool that can test right away whether the proposed cooling system for an engine room is properly designed."

Comfort in the VR Lab. Another objective of the ComfSim project is to develop a simulation model for use in conjunction with a new virtual reality environment under development at Siemens ( Virtual Reality). "In our VR lab, we can literally plunge into the world of virtual reality," says Neuhierl. "Three years from now, we will be able to sit here with decision-makers and design the interior of a new high-speed train. Or we’ll be able to see what impact structural modifications have on a glazed building and how this affects air currents and fire safety in individual rooms . The system will be able to tell us immediately where there is turbulence, where the air is motionless, how an open window changes the airflow, and where the building is losing heat."

And that’s not all. The ComfSim team at Siemens is also looking to develop an open platform by 2008 which can be accessed by company personnel around the world. "Siemens operates on a decentralized basis. In the future, a team of employees in different locations—one from China, one from the U.S. and one from Germany, for instance—will be able to meet in a VR room and design new products all the way up to a complete power plant," says Bernd Friedrich, head of the Digital Products competence area at CT. Depending on project requirements, they will be able to work from their own PCs or in a local VR room. "We’re getting closer all the time to actual physical reality. The ComfSim model takes into account not only temperature, humidity, airflow and turbulence but also radiant heat issues such as how much the sun heats up the surface of, say, the desk in my office." So, in the future, will the office atmosphere be perfect? "As far as the air conditioning and ventilation are concerned, definitely!" says Friedrich with a grin.
                                                                                                              Ulrike Zechbauer