Martin Schmidt's research while affiliated with RWTH Aachen University and other places

Publications (33)

Article
The use of displacement ventilation for cooling environments is limited by the vertical temperature gradient. Current standards recommend a temperature difference of up to 3 K/m between the head and the feet. This paper reviews the scientific literature on the effect of vertical temperature gradients on thermal comfort and compares this to the resu...
Article
Buildings’ smoke extraction systems are commonly designed according to guidelines and standards. This approach does not take all boundary conditions into account that may occur within the lifespan of a building. We introduce a novel approach for evaluating the robustness of smoke extraction systems that incorporates realistic boundary conditions by...
Article
New concepts of removing the cooling loads in shopping centres are presented in a multi-disciplinary study. In air-quality experiments, we found that the air change rate (ACR) in shops can be reduced significantly, while still maintaining acceptable air quality. Dilution curves of typical odour-intensive retail goods were measured, which show that...
Article
Die Entwicklung von Komponenten für lüftungstechnische Anlagen erfordert umfangreiche Testreihen unter realistischen Randbedingungen. Am Lehrstuhl für Gebäude- und Raumklimatechnik (EBC) des E.ON Energy Research Centers der RWTH Aachen steht hierfür ein in Dimension und Funktionalität umfangreicher Prüfstand zur Verfügung.
Conference Paper
Within custom-made energy or HVAC systems, control quality of the widespread PI and PID controllers is in general poor due to high tuning costs for each controller and almost unique specifications of each controlled system. We propose a control tuning method, which needs as little as possible a priori knowledge, which runs as far as possible automa...
Conference Paper
Full-text available
Within custom-made energy or HVAC systems, control quality of the widespread PI and PID controllers is in general poor due to high tuning costs for each controller and almost unique specifications of each controlled system. We propose a control tuning method, which needs as little as possible a priori knowledge, which runs as far as possible automa...
Conference Paper
Full-text available
Ein Lösungsansatz zur Steigerung der Energieeffizienz von gebäudetechnischen Systemen ist die exegetisch optimale Nutzung von Energie auf niedrigem Temperaturniveau. Die Entwicklung von Re-gelstrategien für komplexe Energiesysteme ist dabei eine Herausforderung. Das E.ON Energieforschungszentrum verfügt über ein wegweisendes Energiekonzept unter Nu...
Conference Paper
Full-text available
In this study LES simulation was applied to modeling of the internal and external flow patterns of an active chilled beam. The active chilled beam is a supply device based on induction principle combining outdoor air supply with cooling of recirculated room air. The LES simulation results were compared to RANS results with SST k-ƒÖ and k-. turbulen...
Conference Paper
Full-text available
The three-dimensional air flow pattern inside an active chilled beam is investigated in detail using 2D particle image velocimetry (PIV). Measurements were conducted using an experimental setup containing an optically accessible, generic geometry of an active chilled beam. Dimensions were chosen to be similar to devices for typical office applicati...
Conference Paper
Full-text available
The energy demand in shopping centers in the mild climate of Central Europe is high due to high cooling loads which can appear even in winter. This is caused mainly by the intense lighting of the sales products. The heat is removed by conditioned air and additional circulating air cooling units in case the preinstalled air conditioning system is no...
Conference Paper
Full-text available
We assess different control loop tuning methods to tackle suboptimal building performance due to suboptimal PID control within building automation systems. Advanced control research for building energy systems is usually conducted either simulation-based or with the help of experiments via test benches. Therefore, it is limited in terms of applicab...
Conference Paper
Full-text available
The authors introduce a multifunctional control research test bench and its data management and interface system. They implemented a building monitoring, control, and interface system (MCIS) used for evaluation of complex building energy systems, for optimization of such energy systems and for carrying out control research experiments. In this pape...

Citations

... On the other hand, ASHRAE 55-2017 [24] indicated that the vertical air temperature difference between the head and ankle levels should not exceed 3 • C for seated occupants and 4 • C for standing occupants for the thermal comfort condition. Although recent studies, such as Mohlenkamp et al. [31], reported that the acceptable vertical temperature gradient for the thermal comfort of occupants might be much larger than this comfort standard, the strong thermal stratification of the indoor space of gers can be recognised as completely different from the fully air-conditioned environment of modern buildings with relatively uniform temperature distribution. ...
... Therefore, if a mechanical ventilation system like that in the underground subway station is built in the depot, it may result in waste of investment. Comparing with mechanical ventilation (MV) system, the mean visibility range with the natural ventilation (NV) system is much higher than with mechanical ventilation system, because the smoke layer in NV system has a better stability (Wesseling et al., 2019). However, natural ventilation systems are often unstable due to the surrounding environment and weather (Kr ol, M., 2016). ...
... Due to the economic considerations, experimental investigations of studies regarding cabin indoor air environments are usually conducted on dedicated test benches at ground level. However, some available studies were only focused on cabin layouts characterized by single-aisle configurations [14,15]. Twin-aisle cabin layouts were considered by experimental studies in a cabin mock-up based on a 767-300 section [16,17]. ...
... sented, a constant volume flow of 200 m³/h (corresponding to an air change rate of 20 1/h or 18.5 L/s per person) was used.[46][47][48] ...
... Because the supply air enters the room through ten slot diffusers (five on each side of the room), different unsteady ventilation strategies can be compared with conventional ventilation. In the experiments described by Roth [46] and Schmidt et al. [47], two unsteady ventilation strategies are investigated: ...
... sented, a constant volume flow of 200 m³/h (corresponding to an air change rate of 20 1/h or 18.5 L/s per person) was used.[46][47][48] ...
... sented, a constant volume flow of 200 m³/h (corresponding to an air change rate of 20 1/h or 18.5 L/s per person) was used.[46][47][48] ...
... Climate, E.ON Energy Research Center (E.ON ERC), RWTH Aachen University, Germany (Möhlenkamp et al. 2015;Müller et al. 2015;Fütterer et al. 2013) The range of test facilities at E.ON Energy Research Center (ERC), located on the RWTH Aachen University campus, reaches from climate chambers over generic constructions of indoor environments to a living lab in a real building (see Fig. 7.7). The Aachen Comfort Cube (ACCu) is a highly modular climate chamber and enables the evaluation of thermal comfort under very precise boundary conditions. ...
... Extracts from the results of these studies on the effect of vertical temperature gradient in modified form are published with partly different data basis elsewhere. [41][42][43][44] ...
... 20 Thus, more sophisticated turbulence modelling in terms of LES (Large Eddy Simulation) was applied in our study and the results have shown the LES modelling fit the measured induction ratios and velocity fields better. 21,22 However, all studies carried out so far have been lacking in variations in the physical boundary conditions in order to identify relevant influences on the induction behaviour. ...