Comparison of Various Methods for Calculating the Cooling of Premises at the Termination of Heat Supply

The relevance of the study is related to the need to ensure the safety of human life and building structures of the building and the presence of significantly different approaches to solving the problem of cooling the premises in emergency modes. The subject of the study is the time dependences for lowering the internal temperature in buildings when the heat supply is turned off by the heat supply system in an emergency situation in conditions of a sharp cold snap. The purpose of the study is to assess the reliability of each variant of such dependence and to identify the scope of their applicability. The objective of the study is to compare the behavior of indoor temperature according to different methods and, if necessary, to search for correction coefficients that ensure the best agreement of the results. A combination of approximate analytical and numerical finite-difference methods for solving differential equations of unsteady thermal conductivity in an array of room fences is used, allowing to establish a connection between the basic geometric and thermal parameters of enclosing structures with the rate of cooling of rooms at various points in time. A comparison of two solutions to the problem under consideration is presented – with an exponential decrease in excess internal temperature based on an analogy with the regular cooling regime of a solid and a refined, fair for the initial moments of time, taking into account the peculiarities of the propagation of a temperature wave in massive enclosures. The scope of applicability of each of the solutions is revealed and corrections for the first variant are obtained, ensuring the most accurate coincidence of the results given by them with calculations according to the computer program developed by the author. The presentation is illustrated with numerical and graphical examples.

O.D. SAMARIN, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

National Research Moscow State University of Civil Engineering (26, Yaroslavskoe Highway, Moscow, 129337, Russian Federation)

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