Air humidity, temperature and light conditions are factors that people perceive unconsciously upon entering a room, making up the overall sensory impression described simply as the “room atmosphere.” For modern building control systems, achieving this atmosphere involves a host of concrete measurement data and monitoring processes.

Dr. Osman Ahmed
 
 
Dr. Osman Ahmed, head of engineering at Siemens Building Technologies in the USA, has filed patents for eleven inventions in the field of building controls since 1988. He describes a typical process in a building control system as follows: “A sensor measures the actual temperature and forwards it to a computer, which compares it with the desired temperature. A signal is then sent to a device that adjusts the temperature accordingly. That’s the classic control circuit.”

These processes used to be carried out by four or five different components. Ahmed has now found a way to combine all these processes on a single platform. These so-called MEMS (Micro Electro-Mechanical System) platforms are only the size of a semiconductor chip, but they still pack in a vast number of functions. For example, they can measure a draft, process the corresponding data and radio it to a station. At the same time they can be produced very cheaply in large quantities.

Another advantage of MEMS is that they can be equipped with wireless modules, thereby saving up to 70 percent on installation costs. “Present-day sensor systems usually have two things in common,” said Ahmed, “namely wires for the power supply and wires for transmitting signals to the control center. That means high costs because the time spent for installation and possibly tracing faults is immense. MEMS on the other hand do not need to be wired and they transmit their signal to a switching station by radio. This signal could contain data about the room atmosphere or a fire alarm, or even surveillance pictures from tiny MEMS cameras.”

A dense network of sensors in the building can detect drafts, a rise in the temperature if the workplace is exposed to sunshine, or stuffy air that needs changing. This information is used to improve the room atmosphere, create a better working environment in offices, universities or stores, and boost efficiency. Ahmed believes that building controls will become more important thanks to cost-saving innovations such as semiconductor platforms and wireless communications. “Monitoring can be extended beyond the classic areas such as temperature and air quality to other areas and appliances. The trend is moving away from straightforward building controls to the intelligent use of room information in the building.”

In a field test, Ahmed used this method to measure the carbon dioxide and ammonia content in mouse cages. When MEMS in the mouse cages detect a high carbon dioxide and ammonia content, this is an indication that the air is stifling and the straw needs to be changed.

A dense network of sensors in the building can detect drafts, a rise in the temperature if the workplace is exposed to sunshine, or stuffy air that needs changing. This information is used to improve the room atmosphere, create a better working environment