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Indoor Temperature (indoor + temperature)
Selected AbstractsDifferences between young adults and elderly in thermal comfort, productivity, and thermal physiology in response to a moderate temperature drift and a steady-state conditionINDOOR AIR, Issue 4 2010L. Schellen Abstract, Results from naturally ventilated buildings show that allowing the indoor temperature to drift does not necessarily result in thermal discomfort and may allow for a reduction in energy use. However, for stationary conditions, several studies indicate that the thermal neutral temperature and optimum thermal condition differ between young adults and elderly. There is a lack of studies that describe the effect of aging on thermal comfort and productivity during a moderate temperature drift. In this study, the effect of a moderate temperature drift on physiological responses, thermal comfort, and productivity of eight young adults (age 22,25 year) and eight older subjects (age 67,73 year) was investigated. They were exposed to two different conditions: S1-a control condition; constant temperature of 21.5°C; duration: 8 h; and S2-a transient condition; temperature range: 17,25°C, duration: 8 h, temperature drift: first 4 h: +2 K/h, last 4 h: ,2 K/h. The results indicate that thermal sensation of the elderly was, in general, 0.5 scale units lower in comparison with their younger counterparts. Furthermore, the elderly showed more distal vasoconstriction during both conditions. Nevertheless, TS of the elderly was related to air temperature only, while TS of the younger adults also was related to skin temperature. During the constant temperature session, the elderly preferred a higher temperature in comparison with the young adults. Practical Implications ,Because the stock of fossil fuels is limited, energy savings play an important role. Thermal comfort is one of the most important performance indicators to successfully apply measures to reduce the energy need in buildings. Allowing drifts in indoor temperature is one of the options to reduce the energy demand. This study contributes to the knowledge concerning the effects of a moderate temperature drift and the age of the inhabitants on their thermal comfort. [source] An experimental and mathematical study of efforts of a novel photovoltaic-Trombe wall on a test roomINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2008Ji Jie Abstract A novel photovoltaic-Trombe wall (PV-TW) is proposed and investigated experimentally and theoretically in this paper. The PV-TW was installed at the south-facing external wall of an environmental chamber that carried two identical test rooms. Both of the test rooms have a double window of the same size. One test room was installed with the PV-TW (known as the PV-TW room), and the other without PV-TW (known as the reference room). The influence of the PV-TW on the thermal environment of the test room was investigated under different operating conditions. The experimental results show the dual benefits of the PV-TW system: improving the room thermal condition and at the same time generating electricity. Compared with the reference room, the maximum indoor temperature was found to be 5,7°C higher in winter, and the daily electrical output reached about 0.3,kWh with a PV cell area of 0.72,m2. Also, a detailed model is given to evaluate the performance of PV-TW theoretically, and the PV-TW room is simulated under one certain operating condition. The simulated and measured air temperatures of PV-TW room are found to be in good agreement. Copyright © 2007 John Wiley & Sons, Ltd. [source] Der Beitrag von Profilblechdecken zur passiven KühlungBAUPHYSIK, Issue 2 2009Bernd Döring Dr.-Ing. Berechnungsverfahren; Energieeinsparung; Wärme Abstract Die Ausnutzung der thermischen Speichermasse eines Gebäudes zur Beeinflussung der Raumtemperaturen bzw. zur Reduzierung des Energieverbrauchs war in der Vergangenheit Gegenstand zahlreicher Forschungsvorhaben. Um den Einfluss der Speichermasse ermitteln zu können, werden häufig thermische Gebäudesimulationsprogramme eingesetzt, aber auch die aktuelle Fassung von DIN V 18599 berücksichtigt die Wirkung der Wärmekapazität der raumumfassenden Flächen. Sowohl bei Anwendung von DIN V 18599 als auch bei der Gebäudesimulation geht man dabei von einer eindimensionalen Schichtenfolge für Wände und Decken aus. Es gibt jedoch Bauteile, wie z. B. Profilblechdecken, bei denen diese Annahme nicht zutreffend ist. In diesem Bericht werden nun über die Auswertung dynamischer FEM-Berechnungen für inhomogene Deckenaufbauten Ersatzgrößen bestimmt, so dass die Definition einer thermisch äquivalenten Decke als eindimensionales Modell möglich ist. Für ausgewählte Beispiele wird die Wirksamkeit dieser Decken hinsichtlich ihrer Wärmeaufnahme und -abgabe untersucht. The potential of profiled steel sheet deck systems in reference to passive cooling strategies. The use of the thermal inertia of building components to improve the indoor temperature and to reduce the energy consumption was covered in various research projects in the past. Generally, thermal building simulation tools (TRNSYS, TAS, e.g.) are used for the assessment of the effect of thermal inertia, and also the current version of the standard DIN V 18599 takes the effect of the heat capacity of the affected surfaces. Both, DIN V 18599 and thermal building simulation tools, assume a one-dimensional characterization of walls and flooring systems, that means they are assembled based on plane layers. This approach is not valid for inhomogeneous components like profiled steel sheet deck systems. In this report thermal equivalent values for such elements are developed, based on the analysis of transient Finite Element Calculations (FEM), thus the one-dimensional are suitable using these equivalent properties. For a selection of available profiles the effect of such deck systems referring heat-intake and heat-disposal was investigated. [source] Untersuchungen zum Raumklima und zur Fensterlüftung in SchulenBAUPHYSIK, Issue 2 2009Gruppenleiterin Raumklimaqualität Bauphysik Allgemein; Energieeinsparung Abstract Es gibt mehr als 40.000 Schulgebäude in Deutschland, von denen die meisten noch auf eine Sanierung warten. Sanierungen sollen nicht nur dazu dienen, den energetischen Standard der Gebäude zu verbessern, sondern sollten in erster Linie dazu genutzt werden, die raumklimatischen Bedingungen in den Klassenräumen für Schüler und Lehrer zu verbessern. Da die meisten deutschen Schulgebäude nicht mit Raumlufttechnischen Anlagen ausgestattet sind, werden die Räume durch freie Fensterlüftung, betätigt durch die Lehrer und Schüler, belüftet. Daher ist das Fensteröffnungsverhalten der Nutzer von Interesse. Der Einfluss des Fensteröffnungsverhaltens der Nutzer auf die raumklimatischen Bedingungen in den Klassenräumen wurde in zwei Schulen untersucht. Innentemperatur, Kohlendioxidkonzentration sowie die außenklimatischen Bedingungen wurden gemessen. In einer Schule wurde die Fensteröffnungszeit erfasst. Neben hohen Kohlendioxidkonzentrationen besonders während der Heizperiode, sind einige Klassenräume im Winter zu kalt und zu warm im Sommer. Einige Klassenräume haben keinen Sonnenschutz, oder der Sonnenschutz ist unzureichend oder er behindert die Belüftung des dahinterliegenden Raumes. Die Fenster werden zu einem gewissen Grad während des Unterrichts und in den Pausen genutzt. Jedoch werden die Fenster nach dem Unterricht geschlossen und bleiben geschlossen bis zum nächsten Morgen. Es wird keine Nachtlüftung oder Lüftung in den frühen Morgenstunden praktiziert. Signifikante schwache bis moderate Korrelationen zwischen der Fensteröffnungszeit und der Innentemperatur wurden gefunden. Die Korrelation zwischen der Fensteröffnungszeit und der Außentemperatur ist in den meisten Fällen nicht signifikant oder ist nur schwach ausgeprägt. Investigations on indoor environmental conditions and natural ventilation in school buildings. There are more than 40,000 school buildings in Germany. Most of them are awaiting retrofitting. Retrofitting is not only intended to improve the energetic standards, but first of all to improve indoor environmental conditions for pupils and teachers. As most of German schools are not equipped with mechanical ventilation systems, natural ventilation controlled by the occupants opening the windows is the main way to maintain healthy and comfortable conditions in the classrooms. For that purpose the influence of window opening behaviour of the occupants on the indoor environment was measured in two German schools. Temperature and carbon dioxide concentration of the indoor air as well as the outdoor climate conditions were measured. In one school the frequency of window opening was recorded. Besides high CO2 -concentrations especially during winter, some of the investigated classrooms are additionally to cold in winter or to hot in summer. Some classrooms do not have a shading device or the shading device is insufficient or it constricts the ventilation of the room. Windows are used as controls in some degree during lessons and during the breaks. But windows get closed after lessons and stay closed until next morning. There is no night or early morning ventilation in summer. A significant weak to moderate positive correlation between total open window ratio and indoor temperature has been found. Correlation between total open window ratio and outdoor temperature is not significant in most cases or show a weak correlation coefficient. [source] Window pane condensation and high indoor vapour contribution , markers of an unhealthy indoor climate?CLINICAL & EXPERIMENTAL ALLERGY, Issue 3 2000Emenius Objective The aim of this study was to investigate whether window pane condensation and indoor vapour contribution , 3 g/m3 could be used as indicators of defective air change rate, high indoor humidity and high mite allergen concentration in mattress dust. Methods Actual ventilation rate, indoor temperature, air humidity (AIH/RH) and concentrations of mite allergen were measured in 59 houses and compared with received outdoor temperatures and air humidity. Indoor vapour contribution defined as the difference between the indoor and the outdoor vapour concentration was calculated. Sensitivity, specificity, predictive values and accuracy were calculated for window pane condensation and high vapour contribution (, 3 g/m3), as indicators of defective ventilation (< 0.5 ACH), high indoor humidity (, 7 g/kg and , 45% RH) and high mite allergen concentration in mattress dust (, 2 ,g/g). Results All houses with high humidity and high mite allergen concentrations were positive for the two indicators (high sensitivity), but with a specificity of only 50% so that half of the houses with reported condensation and high vapour contribution turned out to be low pollution houses with adequate high ventilation levels. Both indicators had high negative predictive values and absence of the two indicators almost certainly (97,100%) excluded high indoor pollution with high humidity and high mite concentrations. Overall more than 70% of the dwellings were correctly classified by the two indicators. Conclusion Absence of window pane condensation on double-glazed windows and low indoor vapour contribution (< 3 g/m3) during the winter are true markers of a dwelling without high indoor air humidity and without high mite allergen concentrations in mattress dust in houses in a cold temperate climate with subzero outdoor temperatures. The presence of the two indicators is associated with a 18,45% risk of high humidity and mite allergen concentrations so in this latter group further measurements are needed for correct classification. [source] | ||||||||||