Publication detail

Modelling of radiative heat transfer in building envelopes

VALA, J. ŠŤASTNÍK, S. STEUER, R.

Original Title

Modelling of radiative heat transfer in building envelopes

English Title

Modelling of radiative heat transfer in building envelopes

Type

journal article - other

Language

en

Original Abstract

Heat propagation in buildings, namely in their envelopes, is determined by quasi-periodic climatic conditions from external environment and by insulation and accumulation properties of particular material layers. A typical phenomenon of many reconstructions of large block of flats from the socialist period in Czechoslovakia is the presence of algae and the consequent surface degradation of new insulation systems; the same can be observed even in case of new building objects, even of those with insulation layers made from special modern materials. This phenomenon can be explained by the night condensation of vapour from porous material structures, driven by the thermal radiation from building envelopes to the clear sky. Consequently, reliable computational modelling of heat transfer should include both time-variable heat conduction and convection through particular constructive and insulation layers and short-wave (from sun through atmosphere to earth surface) and long-wave (back to atmosphere) radiative supplements, coupled with propagation of moisture in various phases in pores, although some of above sketched processes cannot be easily characterized by deterministic mathematical relations. The quantitative analysis of radiative components is significant for all producers of outer coatings because the decrease of emissivity is able to avoid condensation of vapour at all.

English abstract

Heat propagation in buildings, namely in their envelopes, is determined by quasi-periodic climatic conditions from external environment and by insulation and accumulation properties of particular material layers. A typical phenomenon of many reconstructions of large block of flats from the socialist period in Czechoslovakia is the presence of algae and the consequent surface degradation of new insulation systems; the same can be observed even in case of new building objects, even of those with insulation layers made from special modern materials. This phenomenon can be explained by the night condensation of vapour from porous material structures, driven by the thermal radiation from building envelopes to the clear sky. Consequently, reliable computational modelling of heat transfer should include both time-variable heat conduction and convection through particular constructive and insulation layers and short-wave (from sun through atmosphere to earth surface) and long-wave (back to atmosphere) radiative supplements, coupled with propagation of moisture in various phases in pores, although some of above sketched processes cannot be easily characterized by deterministic mathematical relations. The quantitative analysis of radiative components is significant for all producers of outer coatings because the decrease of emissivity is able to avoid condensation of vapour at all.

Keywords

heat and moisture transfer in buildings, porous material structures, thermal insulation, thermal accumulation, short- and long-wave radiation, numerical modelling, laboratory measurement methods

RIV year

2007

Released

01.09.2007

Publisher

Slovenská štatistická a demografická spoločnosť

Location

Bratislava

ISBN

1336-7420

Periodical

Forum Statisticum Slovacum

Year of study

3

Number

2

State

SK

Pages from

223

Pages to

228

Pages count

6

Documents

BibTex


@article{BUT44253,
  author="Jiří {Vala} and Stanislav {Šťastník} and Radek {Steuer}",
  title="Modelling of radiative heat transfer in building envelopes",
  annote="Heat propagation in buildings, namely in their envelopes, is determined by quasi-periodic climatic conditions from external environment and by insulation and accumulation properties of particular material layers. A typical phenomenon of many reconstructions of large block of flats from the socialist period in Czechoslovakia is the presence of algae and the consequent surface degradation of new insulation systems; the same can be observed even in case of new building objects, even of those with insulation layers made from special modern materials. This phenomenon can be explained by the night condensation of vapour from porous material structures, driven by the thermal radiation from building envelopes to the clear sky.
Consequently, reliable computational modelling of heat transfer should include both time-variable heat conduction and convection through particular constructive and insulation layers and short-wave (from sun through atmosphere to earth surface) and long-wave (back to atmosphere) radiative supplements, coupled with propagation of moisture in various phases in pores, although some of above sketched processes cannot be easily characterized by deterministic mathematical relations. The quantitative analysis of radiative components is significant for all producers of outer coatings because the decrease of emissivity is able to avoid condensation of vapour at all.",
  address="Slovenská štatistická a demografická spoločnosť",
  chapter="44253",
  institution="Slovenská štatistická a demografická spoločnosť",
  journal="Forum Statisticum Slovacum",
  number="2",
  volume="3",
  year="2007",
  month="september",
  pages="223--228",
  publisher="Slovenská štatistická a demografická spoločnosť",
  type="journal article - other"
}