SAFETY OF BUILDING SYSTEMS. ECOLOGICAL PROBLEMS OF CONSTRUCTION PROJECTS. GEOECOLOGY

PROBABILISTIC-STATISTICAL MODELING OF ANNUAL VARIATION OF OUTSIDE AIR TEMPERATURE AND ITS VALUES IN THE WARM SEASON

Vestnik MGSU 3/2018 Volume 13
  • Samarin Oleg Dmitrievich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Assistant Professor, Assistant Professor, Department of the Heat and Gas Supply and Ventilation, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 378-384

Subject: the ways for obtaining the sets of climate data for simulation of air and thermal regime of the building premises and assessment of its annual energy consumption are considered. It is noted that most modern approaches in this field rely on the concept of a “typical year”, and therefore unsuitable for engineering practice as they require the search, accumulation and selection of a large number of climatic parameter values. Research objectives: generalization of probabilistic approach to obtaining the sets of climatic data for the case of a study of annual variation in the average daily temperature of outdoor air and creation of a set of outdoor temperatures during the warm season (cooling period). Materials and methods: in this work, we used the software generation of climatic data sets by Monte Carlo method using a pseudorandom number generator based on a linear congruence algorithm. The regular seasonal variation of outside temperature is accounted for by using the “floating” mathematical expectation and the standard deviation. A numerical model of non-stationary thermal regime of a ventilated room is implemented based on the solution of a system of differential equations of heat conduction and heat transfer for the surfaces of the room. Results: some results of calculation of the current ambient temperature during the year and in the warm season using Monte Carlo method are presented for climatic conditions of Moscow. We performed comparison of the results of estimation of unsteady thermal regime of a ventilated room when using average daily outside air temperatures during a month obtained from climatic data and from the results of computer simulation. Conclusions: we demonstrated the principal coincidence of the statistical distribution of outside air temperature and temperature variation of the internal air for both compared variants. It is noted that Monte Carlo simulation gives the results that are indistinguishable, from the standpoint of engineering needs, from the use of a “typical year”, and we revealed the possibility of practical implementation of probabilistic-statistical principle of climate data generation for some calculations that concern the systems of air-conditioning and thermal regime of the building. It is proposed to apply the developed methodology for estimation of the annual energy consumption of buildings and for estimation of efficiency of energy and resource saving.

DOI: 10.22227/1997-0935.2018.3.378-384

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Effect of velocity fluctuations length on the calculation accuracy of turbulent shearing stresses

Vestnik MGSU 9/2014
  • Volgin Georgiy Valentinovich - Moscow State University of Civil Engineering (MGSU) postgraduate student, Department of Hydraulics and Water Resources, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 93-99

This article focuses on the method of improving shear stresses calculation accuracy based on the experimental data. It was proven that shear stresses value considerably changes (even up to change of sign from positive to negative) depending on different velocity fluctuations amount (or length). Experimental database consists of velocity in turbulent flow at different times. Recommendations for practical use of methods of calculation depending on the type of engineering problems are presented. The method of finding optimal amount of the experimental database is proposed by the analysis of the values convergence of the standard deviations calculated for the whole sample and the standard deviation calculated by increasing interval. The calculation results for these intervals are at the points of the measuring system and the hypothesis about finding the optimal length of implementation is offered. The steps for further research are set out.

DOI: 10.22227/1997-0935.2014.9.93-99

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