Hygrothermal properties of building envelopes: Reliability of the effectiveness of energy saving

“…The various opaque and transparent portions of the envelopes were monitored simultaneously in external and internal environments. The aim was to demonstrate the impact of transient natural boundary conditions on the internal structure and surface temperature, heat flow and moisture load [16,21].…”

Section: Measurement Experimental Test Setupmentioning

confidence: 99%

The Influence of the Initial Condition in the Transient Thermal Field Simulation Inside a Wall

Zozulák¹,

Vertaľ²,

Katunský³

2019

Buildings

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The envelope structures of buildings are exposed to heat-humidity conditions. The heat and humidity flow through these structures depends on the boundary conditions of the indoor and outdoor environments. This paper shows different initial conditions for the determination of temperature spread. The aim is to bring certain results of temperature calculated considering the initial conditions. When temperature changes, heat flow also rapidly changes. In certain specific cases, it is necessary to consider the initial conditions of temperature—for example; when transient energy simulations of real buildings are carried out. The reasons as to why it is necessary to consider the initial conditions, are shown in the examples of one-layer assemblies. The test walls exposed to the transient hygrothermal conditions are placed in the outdoor test cell. The cell has a stable temperature and relative humidity, and outdoor weather conditions change. The measured data on these walls and the calculated values of the temperatures in the wall structure, according to the different initial conditions, are compared. The average difference of the mean by the simulation and the measured values is significant. For a simulation time of about five days, the initial condition for calculating the temperature in the center of the masonry is necessary.

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“…for 0 t t 0 , where t 0 = 20 days. The initial conditions (6) mean that in the beginning all pores of the sample are totallyˇlled with liquid (no vapor is present) and the initial temperature is an indoor temperature. The mass and heat ux on the left boundary x = 0 are absent (see conditions (7)).…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

“…Equation (9) represents two parabolic equations from which we determine w k+1/2 assuming that w k is given, for example, by the initial conditions (6). Equation (10) in its component form can be written as…”

Section: Splitting Schemementioning

confidence: 99%

Scheme of splitting with respect to physical processes for a model of heat and moisture transfer

Амирханов

Pavluš

Пузынина

et al. 2015

Phys. Part. Nuclei Lett.

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A difference scheme of splitting with respect to physical processes for a model of heat and moisture transfer is proposed. The model involves three physical processes Å heat, liquid and saturated vapor transfer in the porous material. The density of saturated vapor and the transfer coefˇcients of liquid and vapor moistures depend on the temperature. At the same time, the heat capacity and conductivity of the porous material depend on moisture. On the basis of the proposed scheme of the model, a numerical simulation of the heat and moisture transfer for a drying process has been performed. ‚ · ¡μÉ¥ ¶·¥¤²μ¦¥´ ¸Ì¥³ · ¸Ð¥ ¶²¥´¨Ö, μÉ´μ¸ÖÐ Ö¸Ö ± Ë¨ §¨Î¥¸±¨³ ¶·μÍ¥¸¸ ³ ¤²Ö ³μ¤¥² ¶ ¥·¥¤ Î¨É¥ ¶² ¨¢² £¨. ·¥¤²μ¦¥´´ Ö ³μ¤¥²Ó ¢±²ÕÎ ¥É É·¨Ë¨ §¨Î¥¸±¨Ì ¶·μÍ¥¸¸ Å É¥ ¶²μ, ¦¨¤-±μ¸ÉÓ¨ ¶¥·¥¤ ÎÊ´ ¸ÒÐ¥´´μ£μ ¶ · ¢ ¶μ·¨¸ÉÒÌ ³ É¥·¨ ² Ì. ²μÉ´μ¸ÉÓ ¶μ·¨¸Éμ£μ ³ É¥·¨ ² ± μÔËË¨Í¨¥´ÉÒ ¶¥·¥¤ Î¨¦¨¤±μ¸É¨¨ ¶ · § ¢¨¸ÖÉ μÉ É¥³ ¶¥· ÉÊ·Ò. ‚ Éμ ¦¥ ¢·¥³Ö É¥ ¶²μ¥³±μ¸ÉÓÉ ¥ ¶²μ ¶·μ¢μ¤¨³μ¸ÉÓ ¶μ·¨¸Éμ£μ ³ É¥·¨ ² § ¢¨¸ÖÉ μÉ Ê·μ¢´Ö ¢² £¨. μ¸´μ¢¥ ¶·¥¤²μ¦¥´´μ°³μ¤¥²· §· ¡μÉ ´μ Î¨¸²¥´´μ¥ ³μ¤¥²¨·μ¢ ´¨¥ ¶¥·¥¤ Î¨É¥ ¶² ¨¢² £¨¤²Ö ¶·μÍ¥¸¸ ¸ÊÏ±¨.

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Hygrothermal properties of building envelopes: Reliability of the effectiveness of energy saving

Cited by 37 publications

References 11 publications

Certain Building Materials with Respect to Their Thermal Properties as Well as to Their Impact to Environment

Certain Building Materials with Respect to Their Thermal Properties as Well as to Their Impact to Environment

The Influence of the Initial Condition in the Transient Thermal Field Simulation Inside a Wall

Scheme of splitting with respect to physical processes for a model of heat and moisture transfer

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