Heat Exchange in the Surface of Lightweight Steel Roof Coatings / Šilumos Mainai Plieninių Vėdinamų Stogų Dangų Paviršiuose

Self Cite

Correct evaluation of solar heat gains through fenestration into the rooms has a great impact on energy demand calculations for buildings. This article presents an hourly energy demand calculation method for heating and cooling, which considers the fact that the solar radiation flow passed through the transparent fenestration into the rooms is not adequate to the thermal energy flow. This method considers that the thermal energy flow in the rooms transformed from solar thermal radiation depends on the short-wave thermal radiation absorption coefficient of internal surfaces of the rooms. The value of short-wave thermal radiation absorption coefficient forms a considerable impact on the flow of thermal energy gains in the room. The presented method differs from others on that score that it considers additionally physical lows, according to which the solar short-wave thermal radiation energy admitted into the room is converted into the thermal energy. This hourly method enables precise calculating the hourly mean of indoor temperature and energy demand for heating and cooling of the buildings during the day.

Section: Theoretical Premisesmentioning

confidence: 99%

Section: Theoretical Premisesmentioning

confidence: 99%

Hourly Calculation Method of Building Energy Demand for Space Heating and Cooling Based on Steady-State Heat Balance Equations

Monstvilas

Stankevičius

Karbauskaitė

et al. 2012

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“…the intensity of radiation heat exchange with the environment in external surfaces of the ventilated and non-ventilated envelopes depends on the values of solar radiation absorption coefficient α and emission ε of these surfaces (synnefa et al 2006shi, Zhang 2011). the intensity of convective heat exchange between the boundary surfaces of the ventilated air gap and air flowing in the gap depends on the air flow speed (Banionis et al 2011;Monstvilas et al 2005). Moreover, emission of the boundary surfaces of the ventilated air gap determines the intensity of radiation heat exchange between these surfaces (roels, deurinck 2011).…”

Section: Literature Reviewmentioning

confidence: 99%

On the Solution of Energy Balance Equation System to Predict Temperature Distribution in the Building Elements With Ventilated Air Gap

Monstvilas

Banionis

Poderytė

et al. 2014

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The article presents the solution of heat balance equation system, describing heat exchange processes in ventilated envelopes, which was applied to derive formulas for the calculation of temperatures in the ventilated layers of the envelopes. The accurateness of the formulas was assessed by experimental research and analysis of the calculation results. During the process of heat exchange balance equation solution, the equations were simplified by introducing the following restriction into the derived formulas: they may only be applied for the ventilated envelopes with steel or similar coatings as their external layers, i.e. coatings having small heat capacity and minor difference between the external and internal surface temperatures. The derived formulas enable the calculation of the temperatures of the ventilated envelopes in the distance which does not exceed a half of the ventilated air gap length measuring from the air entrance into the gap. However, this restriction does not impede the estimation of the average thermal indicators of the ventilated envelopes.

“…Multiple combinations of performance parameters and adopted constructional designs may lead to substantial differences in thermal energy efficiency of heating surface and thus increase cost of the entire system. Furthermore, thermal analysis of the horizontal surface is often time dependent since the external climate temperature, wind speed, solar radiation vary with time (Banionis et al 2011(Banionis et al , 2012Tabares-Velasco, Srebric 2012). That is why an efficient and economically viable surface heating system for open space design requires carrying out numerous comparative analyses.…”

Section: Introductionmentioning

confidence: 99%

Structural Solutions Impact on Thermal Energy Efficiency of Heating Surface at an Open Space

Kaczorek

Koczyk

2013

This paper presents studies on thermal energy efficiency of heating surface at an open space according to structural solutions and climatic conditions. Numerical simulation research was conducted to assess three different types of heating surfaces at an open space over chosen period of time in real weather conditions. Performance parameters such as surface temperature, supply temperature and efficiency of heating surface relative to constructional designs and model of control strategy used were analysed. The number, thickness and type of material layers beneath ground level were modified. The distance between heating pipes and their diameters were kept constant. The carried out analyses show that the used solutions can lead to significant differences in the performance and consequently in the energy efficiency of the heating system for open spaces.