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Validation of Building Energy Modeling Tools for a Residential Building in Brasov Area-Romania

Abstract

A building energy model is a simulation tool which calculates the thermal loads and energy use in buildings. Building energy models provide valuable insight into energy use in buildings based on architecture, materials and thermal loads. In addition, building energy models also must account for the effects of the building’s occupants in terms of energy use. In this paper we discuss building energy models and their accuracy in predicting energy use. In particular, we focus on two types of validation methods which have been used to investigate the accuracy of building energy models and on how they account for their effects on occupants. The analyzed building is P + M located in the climatic zone 4, Sânpetru / Braşov. We have carried out a detailed and exemplary energy needs analysis using two methods of analysis.

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Jet Fuels Degradation under Severe Thermal Loads / Degradacja Paliw Lotniczych W Warunkach Wysokich Temperatur

Abstract

Paper presents research results of jet fuels thermal degradation exposed to different thermal loads. This problem is especially important as it influences safety of aircraft operation. Jet fuel in modern engines is used in heat transfer and cooling of different construction elements. Together with new engines’ construction and materials used thermal loads affecting jet fuel become more severe, and thus in aircraft fuel system not well understood phenomena occur, resulting with plugging injectors, valves and affecting elastomers. They affect engine operation and should be well and carefully described and understood to prevent them. Research results presented here are the first data in Poland dealing with jet fuels’ thermal degradation problem. Article is aimed to present the mechanism of jet fuel thermal degradation under different temperatures. The project has been funded by National Science Centre granted with decision no. DEC-2011/01/D/ST8/06567.

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Mathematical Determination of Thermal Load for Fluidised Bed Furnaces Using Sawdust

Abstract

For technical applications, a physical model capable of predicting the particle evolution in the burning process along its trajectory through the furnace is very useful. There are two major demands: all the thermo-dynamic processes that describe the particle burning process must be accounted and the model must be written in such equation terms to allow the intervention for parameter settings and particle definition. The computations were performed for the following parameters: furnace average temperature between 700 and 1200 °C, size of the sawdust particle from 4 to 6 mm and fix carbon ignition between 500 and 900 °C. The values obtained for the characteristic parameters of the burning process ranged from 30 to 60 [kg/(h·m3)] for the gravimetrical burning speed WGh and from 150 to 280 [kW/m3] for the volumetric thermal load of the furnace QV. The main conclusion was that the calculus results are in good agreement with the experimental data from the pilot installations and the real-case measurements in the sawdust working boiler furnaces or pre-burning chambers. Another very important conclusion is that the process speed variation, when the furnace temperature changes, confirms the thermo-kinetic predictions, namely that the burning process speed decreases when the furnace temperature increases.

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Air Exchange Rate in Air Quality Assurance – A Case Study

Abstract

The goals of this paper are to estimate some parameters – indoor temperature and ventilation rate - necessary to determine the heat load demand for ventilation in the amphitheatre named ‘A TALPOSI’-Faculty of Buildings Engineering- with a number of at the most 120 occupants. The study presented in this paper is made when in the amphitheatre it is necessary to assure a comfortable temperature by a permanent functioning of the heating system. The number of air exchanges necessary in the amphitheatre in the natural ventilation process, more exactly, to assure a minimum air exchanges, is imposed by the requirements for the assurance of physiologic comfort in the amphitheatre for the time interval when it is occupied by students. The inner air debit should cover the harmful emissions in the amphitheatre. By the help of these calculated (measured) parameters we have calculated the heat load for ventilation. In the end, with the data obtained from calculations and measurements we find ourselves in the situation of establishing the size of the heat exchanger corresponding to the room, to heat the fresh air taken from outside and send it inside the amphitheatre. The measurements are made with the TESTO apparatus of the faculty. The minimum requirements to assure the thermal comfort are: to achieve a minimum internal temperature θi (t) higher than (or equal to) the normal indoor temperature associated to this space and to assure the air quality, the air exchange rate. The authors want to highlight by this study the necessity and importance of the control on the number of air exchanges in rooms with a high number of occupants and overall, the control of the fresh air debits. The fact that the focus is more and more on heat loss cuts in rooms by tightening closing elements gives birth to the necessity of control of the ventilation system with effects on the consumption of mechanical energy.

Open access
The Potential Cogeneration Thermal Capacity Choice for Heat Source Group

The Potential Cogeneration Thermal Capacity Choice for Heat Source Group

The proposed in the paper heat source cogeneration potential assessment method, is based on the heat sources group gathered heat load duration curve analysis and optimization of installed thermal power of cogeneration unit. Heat loads of sources group are converted into the normative climatic conditions. For the method verification are used Lielvarde heat source operating data in year 2007. The results show that quantitative indicator value differences are small and methods of use are correct. There is investigated cogeneration optimal heat capacity correlation with the source of the average heat capacity, which significantly facilitates the assessment of the potential of CHP in the event if there are available only year fuel consumptions.

During the methods inspection process is performed Lielvarde heat source cogeneration thermal capacity optimization and found that the installed capacity is less than optimal. There are observed possible amounts for heat and power generation in optimal capacity case.

Open access
Static, Vibration and Buckling Analysis of Skew Composite and Sandwich Plates Under Thermo Mechanical Loading

Abstract

Static, vibration and buckling behavior of laminated composite and sandwich skew plates is studied using an efficient C0 FE model developed based on refined higher order zigzag theory. The C0 FE model satisfies the interlaminar shear stress continuity at the interfaces and zero transverse shear stress conditions at plate top and bottom. In this model, the first derivatives of transverse displacement have been treated as independent variables to overcome the problem of C1 continuity associated with the plate theory. The C0 continuity of the present element is compensated in the stiffness matrix formulation by adding a suitable term. In order to avoid stress oscillations observed in the displacement based finite element, the stress field derived from temperature is made consistent with the total strain field by using field consistent approach. Numerical results are presented for different static, vibration and buckling problems by applying the FE model under thermo mechanical loading, where a nine noded C0 continuous isoparametric element is used. It is observed that there are very few results available in the literature on laminated composite and sandwich skew plates based on refined theories. As such many new results are also generated for future reference

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FINITE ELEMENT ANALYSIS OF THERMAL STRESSES IN A PAD-DISC BRAKE SYSTEM (A REVIEW)

brakes, Wear, Vol. 140, No. 2, 291-308. 25. Zhao S., Hilmas G.E., Dharani L.R. (2008), Behavior of a composite multidisk clutch subjected to mechanical and frictionally excited thermal load, Wear, Vol. 264, 1059-1068.

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Numerical Evaluation Of Effective Thermal Properties For Materials With Variable Porosity

under thermal load”, Int J Solids Struct, 52, 114-129. [15] Mori, T. and Tanaka, K. (1973), “Average Stress in the Matrix and Average Elastic Energy of Materials with Misfitting Inclusions”, Acta metallica 21, 571-574. [16] Ochiai, Y. (2001), “Steady heat conduction analysis in orthotropic bodies by triple-reciprocity BEM”, Computer Modeling in Engineering and Sciences 2(4), 435-446. [17] Ozisik, M. N. (1994), Finite Difference Methods in Heat Transfer, CRC Press Inc, Boca Raton, USA. [18] Sladek, J., Sladek, V., Solek, P., Tan, C. L. and Zhang

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A Method of Assessing the Tendency of Aviation Fuels to Generate Thermal Degradation Products Under the Influence of High Temperatures

, Vol. 16, No. 3, pp. 135-140, Warsaw 2009. [19] Sarnecki, J., Gawron, B., Kosiak, A., Dokumentacja ruchowa i oprogramowanie stanowiska badawczego do badań procesu degradacji termicznej paliw lotniczych , Report No. 2/55/2014, AFIT. [20] Sarnecki, J., Innowacyjne stanowisko badawcze do określania stabilności termicznej paliw lotniczych , Journal of Konbin, no 1(29), pp. 15-22, 2014. [21] Sarnecki, J., Jet fuels degradation under severe thermal loads , Journal of KONBIN, no 3 (31), pp. 31-40, 2014. [22] Spychała, J., Kułaszka, A., Giewoń, J

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Experimental Investigation of the Relationship Between Noise Level and Thermal Power Inside the Boiler Plant – Study Case

Abstract

The acoustic comfort of a building or house is typically given little or no attention during project planning and design. This study is aimed at quantifying noise pollution from a building technical room. To attain the research specified result, simultaneous measurements were recorded for the gas flow and noise level in the boiler room. The noise levels were recorded for different operation statuses of the boilers (different thermal loads). It was observed that noise level depends on the thermal load: the increase of thermal load is directly proportional to the noise level inside the plant room). Further, the measured values of the noise level were compared with literature predicted values and the maximum limit values from the Romanian norm. These research findings are useful for mechanical design engineers and architects in order to assure the noise protection and fulfill the residents’ expectations.

Open access