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

ACCOUNTING FOR NONUNIFORMITY OF WATER CONSUMPTION IN THE EXHAUST AIR HEAT RECLAMATION SYSTEMS FOR HOT WATER SUPPLY

Vestnik MGSU 3/2017 Volume 12
  • Samarin Oleg Dmitrievich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Associate Professor, Department of 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 341-345

This article is devoted to assessment of the influence of variation of daily hot water consumption on the predicted energy effect by using heat recovery of exhaust air in typical exhaust ventilation systems of the most commonly used flat buildings during their switch to the mechanical induction for the pre-heating of water for hot water supply. It outlines the general principle of the organization of this method of energy saving and presents the basic equations of heat transfer in the heat exchanger. The article proposes a simplified method of accounting for changes in the heat transfer coefficient of air-to-water heat exchanger with fluctuations of water demand using existing dependencies for this coefficient from the rate flow of heating and heated fluid through the device. It presents observations to identify the parameters of the real changes of water consumption during the day with the main quantitative characteristics of normally distributed random variables. Calculation of thermal efficiency of the heat exchange equipment using dimensionless parameters through the number of heat transfer under the optimal opposing scheme of fluid motion is completed under conditions of variable water flow rate for the type residential building of the П3-1/16 series using the Monte Carlo method for numerical modeling of stochastic processes. The estimation of the influence of fluctuation of the current water consumption on the instantaneous thermal efficiency factor of the heat exchanger and the total energy consumption of the building is given, and it is shown that the error of said calculation using average daily parameters is within the margin of usual engineering calculation.

DOI: 10.22227/1997-0935.2017.3.341-345

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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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