Thermal Conductivity Of Insulation Layer Research Articles

Design and Energy Performance Analysis of a Hotel Building in a Hot and Dry Climate: A Case Study

In times of unprecedented climate change and energy scarcity, the design and delivery of energy-efficient and sustainable buildings are of utmost importance. This study aimed to design a hotel building for hot and dry climate conditions and perform its energy performance analysis using energy simulation tools. The model of the hotel building was constructed by a graphical tool OpenStudio and EnergyPlus following the ASHRAE Standard 90.1. To reduce the energy demand of the hotel, parametric analysis was conducted and building envelope parameters such as the thickness of insulation layer in the exterior wall and the roof, thermal conductivity of insulation layer, rate of infiltration, U-factor of windows, and thermal resistance of air gap in the interior walls (R-value), window-to-wall ratio, and orientation of the building were tested and the impact on the energy use of the building was analyzed. It was found that most of the design assumptions based on the ASHRAE standard were already optimal for the considered locality, however, were still optimized further to reach the highest efficiency level. Apart from this, three sustainable technologies—thermochromic windows, phase change materials, and solar panels—were incorporated into the building and their energy consumption reduction potential was estimated by energy simulations. Cumulatively, these sustainable technologies were able to reduce the total energy use from 2417 GJ to 1593 GJ (i.e., by 824 GJ or 34%). Calculation of payback period and return on investments showed that thermochromic windows and solar panels have relatively short payback periods and high return on investments, whereas PCM was found to be economically nonviable. The findings of this study are deemed to be useful for designing a sustainable and energy-efficient hotel building in a sub-tropical climate. However, the overall design and energy performance analysis algorithm could be used for various buildings with varying climate conditions.

Assessment of buildings with ventilated facade systems and evaluation of point thermal bridges

Analyzes of influence of the point thermal bridges of buildings with ventilated facade systems on the thermal properties of envelops are presented in the paper. The relation between the separate components of the envelop were made: thermal properties and thickness of supporting wall’s layer; value of thermal conductivity and thickness of insulation layer. Studies have shown, that the value of the point thermal transmittance, which depended on the thermal properties of the envelop and thickness of the layers, might increase to 35%. The higher thermal conductivity coefficient of the material of the supporting wall and thickness of the insulation layer, the larger value the point thermal transmittance. And contrary, if the thickness of the supporting wall and coefficient of thermal conductivity of insulation layer was increased, the value the point thermal transmittance was decreased. It is possible to determine the value of thermal bridges of certain construction design solution by simplified calculations, according to the existing dependencies formulas or graphics. In this case it’s necessary to have dependence of the point thermal bridges from thermal insulation properties and dimensions of envelop layers. DOI: http://dx.doi.org/10.5755/j01.sace.11.2.12606

TWO-DIMENSIONAL THERMAL ANALYSIS OF MULTI-LAYER THIN FILM PYROELECTRIC INFRARED DETECTORS

Two-dimensional thermal analysis of multi-layer thin film pyroelectric infrared detectors is performed according to the structure and test conditions of detectors and the temperature distribution of detectors is obtained. Result shows that the insulation layer of multi-layer film pyroelectric infrared detector can effectively reduce thermal flow from pyroelectric layer substrate and the response of detector increases with the increasing of insulation layer thickness; when the thermal conductivity of insulation layer is lower than of air, its performance is better than micro-bridge structure.