1,721,219 research outputs found
Predicted and actual indoor environmental quality: Verification ofoccupants' behaviour models in residential buildings
Full text linkOccupants' interactions with the building envelope and building systems can have a large impact onthe indoor environment and energy consumption in a building. As a consequence, any realistic forecastof building performance must include realistic models of the occupants' interactions with the buildingcontrols (windows, thermostats, solar shading etc.).During the last decade, studies about stochastic models of occupants' behaviour in relation to controlof the indoor environment have been published. Often the overall aim of these models is to enablemore reliable predictions of building performance using building energy performance simulations (BEPS).However, the validity of these models has only been sparsely tested.In this paper, stochastic models of occupants' behaviour from literature were tested against mea-surements in five apartments. In a monitoring campaign, measurements of indoor temperature, relativehumidity and CO2concentration was measured in the living room and bedroom at five minute intervals infive apartments with similar layout in a building located in Copenhagen, Denmark. Outdoor temperature,relative humidity, wind speed and solar radiation were obtained from a weather station close by.The stochastic models of window opening and heating set-point adjustments were implemented inthe BEPS tool IDA ICE. Two apartments from the monitoring campaign were simulated using the imple-mented models and the measured weather data. The results were compared to measurements from themonitoring campaign to get an estimate of the forecast's realism.The simulations resulted in realistic predictions in a sense that the measured values were within orclose to the range of the simulated values. The variation in the simulated and measured variables betweenapartments and over time was similar. However, comparisons of the average stochastic predictions withthe measured temperatures, relative humidity and CO2concentrations revealed that the models did notpredict the actual indoor environmental conditions wel
Accounting for the Uncertainty Related to Building Occupants with Regards to Visual Comfort: A Literature Survey on Drivers and Models
Full text linkThe interactions between building occupants and control systems have a high influence on energy consumption and on indoor environmental quality. In the perspective of a future of "nearly-zero" energy buildings, it is crucial to analyse the energy-related interactions deeply to predict realistic energy use during the design stage. Since the reaction to thermal, acoustic, or visual stimuli is not the same for every human being, monitoring the behaviour inside buildings is an essential step to assert differences in energy consumption related to different interactions. Reliable information concerning occupants' behaviours in a building could contribute to a better evaluation of building energy performances and design robustness, as well as supporting the development of occupants' education to energy awareness. The present literature survey enlarges our understanding of which environmental conditions influence occupants' manual controlling of the system in offices and by consequence the energy consumption. The purpose of this study was to investigate the possible drivers for light-switching to model occupant behaviour in office buildings. The probability of switching lighting systems on or off was related to the occupancy and differentiated for arrival, intermediate, and departure periods. The switching probability has been reported to be higher during the entering or the leaving time in relation to contextual variables. In the analysis of switch-on actions, users were often clustered between those who take daylight level into account and switch on lights only if necessary and people who totally disregard the natural lighting. This underlines the importance of how individuality is at the base of the definition of the different types of users
Verification of stochastic behavioural models of occupants' interactions with windows in residential buildings
Full text linkRealistic characterisation of occupants' window opening behaviour is crucial for reliable prediction of building performance by means of building energy performance simulations. Window opening behaviour has been investigated by several researchers, leading to a variety of logistic regression models expressing the probability with which actions will be performed. But only very few attempts have been made to investigate the reliability of the models. In this paper, data from a measurement campaign in 15 apartments was used to estimate the predictive accuracy of four sets of models of window opening. Initially three models from literature were investigated by comparison of predicted probabilities and the actual measured state of the windows. Data from one of the papers was reanalysed to create new models, based on measurements from single dwellings. These models were used to predict window transition probabilities using data from the field survey. The output was then compared to the measured transitions. Results showed that the models which most accurately predicted both the state of the window (open or closed) and the number of actions on windows had certain characteristics in common: A positive correlation between the probability of opening and CO2 concentration and illumination values and a negative correlation with sun hours and illumination level for closing windows
Validation of Occupants’ Behaviour Models for Indoor Quality Parameter and Energy Consumption Prediction
Full text linkOccupants’ behaviour related to building control system plays a significant role to achieve thermal comfort and air quality in naturally-ventilated buildings. Generally, the published models of occupant's behavior are not validated, meaning that the predictive power has not yet been tested. For this reason, the validation of occupant's behavioral models is an issue that is gaining importance.In this paper validation was carried out through dynamic Building Energy Performance simulation (BEPS); behavioral models of windows opening and thermostats set-point published in literature were implemented in a dynamic BEPS software and the obtained results in terms of temperature, relative humidity and CO2 concentration were compared to real measurements. Through this comparison it will be possible to verify the accuracy of the implemented behavioral models.The models were able to reproduce the general tendencies in the measured temperatures but the simulation results diverged from the measured CO2 concentrations and relative humidity
Occupant behaviour and robustness of building design
Full text linkOccupant behaviour can cause major discrepancies between the designed and the real total energy use in buildings. A possible solution to reduce the differences between predictions and actual performances is designing robust buildings, i.e. buildings whose performances show little variations with alternating occupant behaviour patterns. The aim of this work was to investigate how alternating occupant behaviour patterns impact the performance of different envelope design solutions in terms of building robustness. Probabilistic models of occupants' window opening and use of shading were implemented in a dynamic building energy simulation tool (IDA ICE). The analysis was carried out by simulating 15 building envelope designs in different thermal zones of an Office Reference Building in 3 climates: Stockholm, Frankfurt and Athens.In general, robustness towards changes in occupants' behaviour increased with increasing thermal mass and with decreasing transparent area of the envelope. The importance of the robustness' evaluation is highlighted in this paper, in order to obtain optimized buildings' designs for more accurate and realistic energy predictions
PV-PCM integration in glazed building. Co-simulation and genetic optimization study
Full text linkThe study describes a multi-objective optimization algorithm for an innovative integration of forced ventilated PV-PCM modules in glazed façade buildings: the aim is to identify and optimize the parameters that most affect thermal and energy performances. 1-D model, finite difference method FDM, thermal resistances technique and enthalpy method were applied to describe different façade solutions and transient thermal performance of PCM. The coupling between the PV-PCM façade code implemented in MATLAB and the TRNSYS software was developed to estimate the dynamic thermal energy profiles. An exploratory step has also been considered prior to the optimization algorithm: it evaluates the energy profiles before and after the application of PCM to PV module integrated in glazed building. The optimization analysis investigate parameters such as ventilation flow rates and time schedule to obtain the best combination suiting the PCM performance and external-internal loads. A group of solution were identified on the Pareto front. Savings in thermal loads for the best individual reached 26.4% while the best in temperature increment in operating temperatures was recorded as 6.8% comparing to the design set temperature
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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