Scholarlink

<p>We study the process of thermal-engineering inspections of the buildings. This process includes the in-situ measurements of the densities of heat fluxes and temperature on the surfaces of building envelopes. By using the accumulated measurement data, we compute the reduced heat-transfer resistance and compare it with the required design-basis values in building. It is shown that, in analyzing the heat-transfer resistance of the building envelopes according to the results of inspections, we may encounter methodological errors caused by the natural external thermal actions upon the building and internal nonstationary heat fluxes running in the building envelopes. In the course of the <i>in-situ</i> thermal-engineering inspections of building envelopes of any type, these methodological errors are <i>a&#xa0;priori</i> unknown because the conditions of measurements differ from the conditions of thermal-engineering tests performed in special climatic chambers, where a&#xa0;stationary drop of air temperature is kept between the inner and outer surfaces of the building envelope. For the evaluation of methodological errors obtained in the course of thermal-engineering inspections of the buildings carried out under the <i>in-situ</i> conditions, originating at any day of the calendar year, and lasting for several days, we propose a&#xa0;physico-mathematical model of unsteady heat transfer in the building envelope. In the analyzed model, we take into account the following thermal effects close to the actual situation: temperature of the ambient air; direct and diffused solar radiation, and radiative heat exchange with the ambient medium. We analyze enclosing structures with low and high levels of thermal protection and thermal inertia. We analyze possible values of the methodological errors of thermal-engineering surveys obtained by using the archived meteorological data accumulated in the Moscow region. It is shown that, depending on the season and weather conditions, their values may vary from several percent to several dozens percent. We determine the conditions required to perform the inspections with regard for different levels of methodological errors. The performed comparison of two standard procedures used to determine the heat-transfer resistance demonstrates that these procedures give different levels of methodological errors. The accumulated results should be useful for experts involved in conducting the thermal-engineering surveys of buildings and structures with the help of nondestructive testing methods.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Methodological errors of evaluation of the thermal protection of building envelopes under natural conditions

  • 期刊论文

  • 发表日期：

    2025年2月1日

查看全文
  • E. V. Levin,
  • A. Yu. Okunev

摘要

We study the process of thermal-engineering inspections of the buildings. This process includes the in-situ measurements of the densities of heat fluxes and temperature on the surfaces of building envelopes. By using the accumulated measurement data, we compute the reduced heat-transfer resistance and compare it with the required design-basis values in building. It is shown that, in analyzing the heat-transfer resistance of the building envelopes according to the results of inspections, we may encounter methodological errors caused by the natural external thermal actions upon the building and internal nonstationary heat fluxes running in the building envelopes. In the course of the in-situ thermal-engineering inspections of building envelopes of any type, these methodological errors are a priori unknown because the conditions of measurements differ from the conditions of thermal-engineering tests performed in special climatic chambers, where a stationary drop of air temperature is kept between the inner and outer surfaces of the building envelope. For the evaluation of methodological errors obtained in the course of thermal-engineering inspections of the buildings carried out under the in-situ conditions, originating at any day of the calendar year, and lasting for several days, we propose a physico-mathematical model of unsteady heat transfer in the building envelope. In the analyzed model, we take into account the following thermal effects close to the actual situation: temperature of the ambient air; direct and diffused solar radiation, and radiative heat exchange with the ambient medium. We analyze enclosing structures with low and high levels of thermal protection and thermal inertia. We analyze possible values of the methodological errors of thermal-engineering surveys obtained by using the archived meteorological data accumulated in the Moscow region. It is shown that, depending on the season and weather conditions, their values may vary from several percent to several dozens percent. We determine the conditions required to perform the inspections with regard for different levels of methodological errors. The performed comparison of two standard procedures used to determine the heat-transfer resistance demonstrates that these procedures give different levels of methodological errors. The accumulated results should be useful for experts involved in conducting the thermal-engineering surveys of buildings and structures with the help of nondestructive testing methods.