@article{VoelkerMaempelKornadt, author = {V{\"o}lker, Conrad and M{\"a}mpel, Silvio and Kornadt, Oliver}, title = {Measuring the human body's micro-climate using a thermal manikin}, series = {Indoor Air}, journal = {Indoor Air}, number = {24, 6}, doi = {10.25643/bauhaus-universitaet.3815}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181025-38153}, pages = {567 -- 579}, abstract = {The human body is surrounded by a micro-climate which results from its convective release of heat. In this study, the air temperature and flow velocity of this micro-climate were measured in a climate chamber at various room temperatures, using a thermal manikin simulating the heat release of the human being. Different techniques (Particle Streak Tracking, thermography, anemometry, and thermistors) were used for measurement and visualization. The manikin surface temperature was adjusted to the particular indoor climate based on simulations with a thermoregulation model (UCBerkeley Thermal Comfort Model). We found that generally, the micro-climate is thinner at the lower part of the torso, but expands going up. At the head, there is a relatively thick thermal layer, which results in an ascending plume above the head. However, the micro-climate shape strongly depends not only on the body segment, but also on boundary conditions: the higher the temperature difference between the surface temperature of the manikin and the air temperature, the faster the air flow in the micro-climate. Finally, convective heat transfer coefficients strongly increase with falling room temperature, while radiative heat transfer coefficients decrease. The type of body segment strongly influences the convective heat transfer coefficient, while only minimally influencing the radiative heat transfer coefficient.}, subject = {Raumklima}, language = {en} } @article{VoelkerBeckmannKoehlmannetal., author = {V{\"o}lker, Conrad and Beckmann, Julia and Koehlmann, Sandra and Kornadt, Oliver}, title = {Occupant requirements in residential buildings - an empirical study and a theoretical model}, series = {Advances in Building Energy Research}, journal = {Advances in Building Energy Research}, number = {7 (1)}, doi = {10.25643/bauhaus-universitaet.3813}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181015-38137}, pages = {35 -- 50}, abstract = {Occupant needs with regard to residential buildings are not well known due to a lack of representative scientific studies. To improve the lack of data, a large scale study was carried out using a Post Occupancy Evaluation of 1,416 building occupants. Several criteria describing the needs of occupants were evaluated with regard to their subjective level of relevance. Additionally, we investigated the degree to which deficiencies subjectively exist, and the degree to which occupants were able to accept them. From the data obtained, a hierarchy of criteria was created. It was found that building occupants ranked the physiological needs of air quality and thermal comfort the highest. Health hazards such as mould and contaminated building materials were unacceptable for occupants, while other deficiencies were more likely to be tolerated. Occupant satisfaction was also investigated. We found that most occupants can be classified as satisfied, although some differences do exist between different populations. To explain the relationship between the constructs of what we call relevance, acceptance, deficiency and satisfaction, we then created an explanatory model. Using correlation and regression analysis, the validity of the model was then confirmed by applying the collected data. The results of the study are both relevant in shaping further research and in providing guidance on how to maximize tenant satisfaction in real estate management.}, subject = {Post Occupancy Evaluation}, language = {en} } @article{VoelkerKornadtOstry, author = {V{\"o}lker, Conrad and Kornadt, Oliver and Ostry, Milan}, title = {Temperature reduction due to the application of phase change materials}, series = {Energy and Buildings}, journal = {Energy and Buildings}, number = {40, 5}, doi = {10.25643/bauhaus-universitaet.3816}, url = {http://nbn-resolving.de/urn:nbn:de:gbv:wim2-20181025-38166}, pages = {937 -- 944}, abstract = {Overheating is a major problem in many modern buildings due to the utilization of lightweight constructions with low heat storing capacity. A possible answer to this problem is the emplacement of phase change materials (PCM), thereby increasing the thermal mass of a building. These materials change their state of aggregation within a defined temperature range. Useful PCM for buildings show a phase transition from solid to liquid and vice versa. The thermal mass of the materials is increased by the latent heat. A modified gypsum plaster and a salt mixture were chosen as two materials for the study of their impact on room temperature reduction. For realistic investigations, test rooms were erected where measurements were carried out under different conditions such as temporary air change, alternate internal heat gains or clouding. The experimental data was finally reproduced by dint of a mathematical model.}, subject = {Raumklima}, language = {en} }