Experimental and statistical survey on local thermal comfort impact on working productivity loss in university classrooms

The paper presents an experimental analysis of the relationship between local thermal comfort and productivity loss in classrooms. The experimental investigation was performed in a real university classroom during the winter semester in city of Belgrade. Measurements were taken for four scenarios, with different indoor comfort conditions. Variations were made by setting the central heating system on/off, adding an additional heat source to provoke higher indoor temperatures, and measuring the radiant asymmetry impact. Innovative questionnaires were developed especially for the research, in order to investigate students' subjective feelings about local thermal comfort and indoor environmental quality Local predicted mean vote and predicted percentage dissatisfied indices were calculated using data measured in situ. The results were compared to existing models recommended in literature and European and ASHRAE standards. Student productivity was evaluated using novel tests, designed to fit the purposes of the research. Surveys were conducted for 19 days under different thermal conditions, during lectures in a real classroom, using a sample of 240 productivity test results in total. Using the measured data, new correlations between the predicted mean vote, CO2, personal factor and productivity loss were developed. The research findings imply that local thermal comfort is an important factor that can impact productivity, but the impact of the personal factor is of tremendous importance, together with CO2 concentration in the classroom

Cfd simulations of thermal comfort in naturally ventilated primary school classrooms

The purpose of thermal comfort is to speck the combinations of indoor space environment and personal factors that will produce thermal environment conditions acceptable to 80% or more of the occupants within a space. Naturally ventilated indoors has a very complex air movement, which depends on numerous variables such as: outdoor interaction, intensity of infiltration, the number of openings, the thermal inertia of walls, occupant behaviors, etc. The most important mechanism for naturally ventilated indoors is the intensity of infiltration and thermal buoyancy mechanism. In this study the objective was to determine indicators of thermal comfort for children, by the CFD model based on experimental measurements with modification on turbulent and radiant heat transfer mathematical model. The case study was selected on school children of 8 and 9 years in "France Presern" primary school in Belgrade. The purpose was to evaluate the relationships between the indoor environment and the subjective responses. Also there was analysis of infiltration and stack effect based on meteorological data on site. The main parameters that were investigated are: operative temperature, radiant temperature, concentration of CO2, and air velocity. The new correction of turbulence and radiative heat transfer models has been validated by comparison with experimental data using additional statistical indicators. It was found that both turbulence model correct and the new radiative model of nontransparent media have a significant influence on CFD data set accuracy

Cfd simulations of thermal comfort in naturally ventilated primary school classrooms

The purpose of thermal comfort is to speck the combinations of indoor space environment and personal factors that will produce thermal environment conditions acceptable to 80% or more of the occupants within a space. Naturally ventilated indoors has a very complex air movement, which depends on numerous variables such as: outdoor interaction, intensity of infiltration, the number of openings, the thermal inertia of walls, occupant behaviors, etc. The most important mechanism for naturally ventilated indoors is the intensity of infiltration and thermal buoyancy mechanism. In this study the objective was to determine indicators of thermal comfort for children, by the CFD model based on experimental measurements with modification on turbulent and radiant heat transfer mathematical model. The case study was selected on school children of 8 and 9 years in "France Presern" primary school in Belgrade. The purpose was to evaluate the relationships between the indoor environment and the subjective responses. Also there was analysis of infiltration and stack effect based on meteorological data on site. The main parameters that were investigated are: operative temperature, radiant temperature, concentration of CO2, and air velocity. The new correction of turbulence and radiative heat transfer models has been validated by comparison with experimental data using additional statistical indicators. It was found that both turbulence model correct and the new radiative model of nontransparent media have a significant influence on CFD data set accuracy

Free Cysteine Modulates the Conformation of Human C/EBP Homologous Protein

The C/EBP Homologous Protein (CHOP) is a nuclear protein that is integral to the unfolded protein response culminating from endoplasmic reticulum stress. Previously, CHOP was shown to comprise extensive disordered regions and to self-associate in solution. In the current study, the intrinsically disordered nature of this protein was characterized further by comprehensive in silico analyses. Using circular dichroism, differential scanning calorimetry and nuclear magnetic resonance, we investigated the global conformation and secondary structure of CHOP and demonstrated, for the first time, that conformational changes in this protein can be induced by the free amino acid l-cysteine. Addition of l-cysteine caused a significant dose-dependent decrease in the protein helicity – dropping from 69.1% to 23.8% in the presence of 1 mM of l-cysteine – and a sequential transition to a more disordered state, unlike that caused by thermal denaturation. Furthermore, the presence of small amounts of free amino acid (80 µM, an 8∶1 cysteine∶CHOP ratio) during CHOP thermal denaturation altered the molecular mechanism of its melting process, leading to a complex, multi-step transition. On the other hand, high levels (4 mM) of free l-cysteine seemed to cause a complete loss of rigid cooperatively melting structure. These results suggested a potential regulatory function of l-cysteine which may lead to changes in global conformation of CHOP in response to the cellular redox state and/or endoplasmic reticulum stress

EFFECT AIRCRAFT EXHAUST GASES ON SUM OF GREEN-HOUSE ATMOSPHERE GASES

Global Warming Potential – GWP is an agreed quantity which enables determination of an individual green-house gas effect on a global warming process. GWP quantity illustrates how a unit mass of an observed gas contributes to increase of global warming more than an unique mass of CO2, during certain period of time. The paper shows gases and substances resulted from combustion of aircraft engine fuel , so as their affect to the atmosphere. The paper is a short view of an ecological aspect of aeronautics contibution to climate changes, as well as to results of green-house gas emission

Energetski potencijali vojnih objekata / Energy potentials of military buildings / Потенциал энергосбережения военных объектов

Ekonomska kriza, izuzetno veliko budžetsko izdvajanje za obezbeđivanje potrebnih energenata i usvojena zakonska regulativa iz oblasti energetike nameću potrebu iznalaženja i implementacije pozitivnih rešenja radi dostizanja propisanog i poželjnog stepena energetske efikasnosti. U radu je izvršena preliminarna analiza propisane zakonske regulative za oblast energetike – energetske efikasnosti, izveštaja o problemima u zgradarstvu i projekata kojima su rešavani energetski problemi objekata. Radi dobijanja preliminarnih podataka finansijskih efekata poboljšanja toplotne izolacije objekta, a radi povećanja energetske efikasnosti zgrade, korišćen je neprofesionalan programski paket, a dobijeni rezultati su u okvirima republičkog proseka za objekte analizirane starosti. Sagledavanjem konstruktivnih karakteristika i geografskog položaja ustanovljen je i određen potencijal zgrade za iskorišćenje obnovljivih izvora energije. Rad je pokazao da postoji zakonska obaveza realizacije energetske sanacije zgrade koju koristi Vojska Srbije i preliminarne ekonomske efekte realizacije projekta energetske sanacije i iskorišćenja obnovljivih izvora energije. / The economic crisis, extremely large budgets for providing necessary energy and the adopted legislation in the field of energy impose the necessity of finding and implementing positive solutions in order to achieve a proper and desirable degree of energy efficiency. This paper presents a preliminary analysis of the prescribed legislation in the field of energy - energy efficiency as well as the analysis of the reports on problems in construction engineering and projects used to solve energy problems in buildings. To obtain preliminary data of the financial effects of the implementation of positive solutions for improving the energy efficiency of buildings, a non-professional software package was used and the results obtained were within the framework of the national average for buildings of the same age. The structural characteristics of a building in question and its geographical location point to its specific potential for using renewable energy sources. The paper has shown that there is a legal obligation for the energy retrofit of a building used by the Army of Serbia as well as preliminary economic effects of the energy retrofit project realization and utilization of renewable energy sources. / Экономический кризис и большой расход бюджетных средств на обеспечение необходимых энергоносителей, также как и законодательные постановления в области энергетики создают необходимость в поиске и применении новых положительных решений, с целью удовлетворения предписанного и рекомендуемого уровня энергосбережения. В данной работе проведен предварительный анализ предписанных законодательных актов в области энергетики – энергоэффективности, отчетов о проблемах в строительстве, а также проектов, посвященных проблемам энергосбережения на военных объектах. В процессе повышения энергоэффективности зданий, а также в проведении предварительного анализа финансовой эффективности вследствие повышения теплоизоляции объектов был применен непрофессиональный программный пакет, и его результаты вписываются в рамки среднего потребления энергоресурсов, предписанные государственными нормативами, касающихся объектов с установленной старостью. При оценке конструктивных параметров и географического положения был установлен потенциал зданий для применения возобновляемых энергоресурсов. В работе представлено, что существуют законные обязательства по теплоизоляционному оснащению зданий, которыми пользуются ВСРС, и это будет экономически выгодно, вследствие разработки проектов по теплоизоляции и по применению возобновляемых энергоисточников

EFFECT AIRCRAFT EXHAUST GASES ON SUM OF GREEN-HOUSE ATMOSPHERE GASES

Global Warming Potential – GWP is an agreed quantity which enables determination of an individual green-house gas effect on a global warming process. GWP quantity illustrates how a unit mass of an observed gas contributes to increase of global warming more than an unique mass of CO2, during certain period of time. The paper shows gases and substances resulted from combustion of aircraft engine fuel , so as their affect to the atmosphere. The paper is a short view of an ecological aspect of aeronautics contibution to climate changes, as well as to results of green-house gas emission

Upotreba snaga bazirana na efektima

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