1,721,320 research outputs found
HAM-Tools – a whole building simulation tool in Annex 41
Get PDFHAM-Tools is a building simulation software. The main task of this tool is to simulate transfer processes related to building physics, i.e. heat, air and moisture transport in buildings and building components in operating conditions. The scope of the ECBCS Annex 41 “Whole Building Heat, Air and Moisture Response” was of a high relevance for the testing, development, validation and promotion of the HAM-Tools. The majority of the numerical studies made by this programme were provided for Subtask 1 “Modelling principles and common exercises”. This paper gives an overview of the modelling capabilities of HAM-Tools and some results provided for Subtask 1
Common Exercises in Whole Building HAM Modelling
Get PDFSubtask 1 of the IEA Annex 41 project had the purpose to advance the development in modelling the integral heat, air and moisture transfer processes that take place in “whole buildings”. Such modelling comprises all relevant elements of buildings: The indoor air, the building envelope, the inside constructions, furnishing, systems and users. The building elements interact with each other and with the outside climate. The Annex 41 project and its Subtask 1 has not aimed to produce one state-of–the-art hygrothermal simulation model for whole buildings but rather to stimulate the participants’ own development of such models, or advanced use of related existing models. Subtask 1 dealt with modelling principles and the arrangement and execution of so-called common exercises with the purpose to gauge how well we can succeed in the modelling. The paper gives an overview of the Common Exercises which have been carried out in the Subtask. Based on this activity, some general experiences are reported about how well we are able today to carry out such advanced modelling, and some recommendations for future developments are indicated
Grundkursus i bygningsenergiteknik:Undervisningsnotat
No full textLecture note for course 64040, Basic Course in Building Energy Technology. Sections on: Building structures, Heat transmission by conduction; Radiation; Heat transmission by convection; Heat transport in dry insulation materials; Criteria to determine the degree of insulation; Comment on and supplement to Danish Standard, DS 418; The thermal indoor climate; Electrical utilities; The outdoor climate and weather data; Solar radiation; Solar transmittance; Windows; Moisture transport; and Exercises
Impact of furnishing on room airflow
Get PDFIn building simulation it is common to use idealized empty rooms for simulation. However, furnishing elements may cause local microclimates. These microclimates can be critical for instance if furniture is placed close to poorly insulated external walls in Nordic countries, where the external temperatures in the winter season may lead to condensation or high relative humidity on the internal side of the building envelope. Therefore it was important to investigate the influence of furniture on the airflow patterns in rooms and on the local airflow behind the furniture. The current paper presents an investigation of the airflow patterns behind a piece of furniture placed near a cold external wall. The investigation is based on a combination of Particle Image Velocimetry experiments and Computational Fluid Dynamics. The main topic of the investigation is to highlight the effect of increasing the distance between the wall and the furniture as well as between the wall and the floor. As expected the results showed that increased gap widths give increased airflow rates. Comparison of measurements and simulations indicated a good predictability for the cases, where radiation played a minor role
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
From EMPD to CFD – overview of different approaches for Heat Air and Moisture modeling in IEA Annex 41
Get PDFThis paper provides an overview of the recent developments of Heat, Air and Moisture modeling of Whole Buildings, which were carried out within a collaborative project of the International Energy Agency. The project has strived to advance the possibilities to calculate the integrated phenomena of heat, air and moisture flows while including the important interactions that take place in buildings between the various building materials, components, and room air, and how those conditions are influenced by occupants and HVAC systems. Principles and some applications of different levels of modeling are presented: simplified modeling of moisture buffering, whole building coupled models as well as more detailed contributions for airflow modeling, including CFD models
Development of interior relative humidity due to self-desiccation in blended cementitious system
No full textIn engineering practise, interior relative humidity (RH) of concrete significantly affects the transport properties and thus the service life of concrete structures. In this paper, the development of RH due to self-desiccation in blended cement pastes was studied from 1 day to 1.5 years. The pore structure and non-evaporable water content at same ages were determined by mercury intrusion porosimetry and thermogravimetric analysis, respectively. The results revealed that interior RH was significantly reduced at the first 105 days’ curing and falls off slightly afterwards, regardless of water to binder ratios and type of blends. Compared to ordinary Portland cement (OPC) paste, the OPC paste blended with slag shows much lower interior RH, whereas the addition of fly ash slightly increases the interior RH. Minor amount of limestone addition i.e., 5% wt. greatly increases the RH in ternary system consisting of OPC, slag and limestone, whilst slightly decreases the RH in OPC paste blended with fly ash. In the presence of blends, high total porosity corresponds to low interior RH. In case of self-desiccation, it is concluded that interior RH is mainly controlled by average pore size in the cement-based materials.Materials and Environmen
Variations on the Author
Get PDF“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
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