Ralf Stöber

Transmitter power influence in a wireless-signal-based system used to monitor catalyst states

We have recently proposed a stochastic microwave-based measurement approach for the loading state of the catalysts used in automotive aftertreatment systems. In this approach, the interior of the catalyst housing acts as a wireless channel between two end devices of a communications system. It was shown that, depending on the transmission channel characteristics, the properties of the catalyst such as its state can be inferred from the properties of some random function such as the received time response (a random function of time) or its Fourier transform, the received spectrum (a random function of frequency). This publication presents results on the resolution of the measurement method when the normalized cross-correlation function between the received spectra with respectively unloaded and loaded catalyst is used as random function. In particular, we have investigated the influence of the transmit signal power. Measurements and signal evaluation were performed for diesel particulate filter (DPF) with different soot loads probed with an ultra wideband (UWB) system and subsequent processing of the waveform in the frequency domain.

Smart Heating System for Old Buildings - An Approach to the Decentralized Use of Renewable Energies

The central heating units of buildings are typically replaced every 20 to 30 years. There exists a variety of solutions for fuel-and gas-based units, but it would be advantageous to be able to use renewable energies. This would become possible by the combination of planar carbon-fiber-based infrared (IR) radiant heating foils with a heat pump providing hot water. The main goal of our proposed overall control strategy is to increase the energy efficiency while maintaining the thermal comfort for the residents. We examined the electromagnetic compatibility of the heating foils and simulated the relative contributions of the amount of energy provided by the heat pump and by the heating foils to obtain a maximum coefficient of performance for the combined heating system.