Effects of the physical properties of building envelopes on heat transfer timelag and decrement factor (Case study: high-rise buildings in Hamadan)

Subject Areas : environmental management

Mahdi Sharifi ¹ , Vahid Ghobadian ²

1 - PhD Candidate of Architecture, Art and Architecture College of Islamic Azad University, Central Tehran Branch, Tehran, Iran.* (Corresponding Author)
2 - Assistant Professor of Architecture, Art and Architecture College of Islamic Azad University, Central Tehran Branch, Tehran, Iran.

Received: 2015-06-04 Accepted : 2015-10-19 Published : 2017-03-21

Keywords: Time lag, Decrement factor, Properties of envelopes, Heat transfer,

Abstract :

reduce environmental pollution and to improve environmental conditions have been the main requirements for building construction. Envelopes are those parts of buildings that have a considerable impact on energy consumption. That is why the study of envelopes behavior is especially important. In addition, heat transfer between the envelopes is the main factor of changes in the internal temperature and affects directly the heating and cooling load and thermal comfort of the interior space. This paper aims to study the thermal behavior of the envelopes in buildings and to achieve transparent envelopes with appropriate function in the buildings of Hamedan. Method: This study has been conducted using an experimental method. The internal temperature and the temperature near the envelope on both inner and outer sides of high-rise buildings with glazed facades in Hamadan have been registered using the environmental measurement tool. According to the obtained data, two parameters of heat transfer time lag and decrement factor have been analyzed. Then, the behavior of the envelopes has been studied by a numerical analogy and logical reasoning. Findings: According to the calculation of the time lag, this study shows that in Hamadan, double glazing has a better performance (50%) than single tempered glazing due to the desirability of longer time lag and less decrement factor. In addition, in terms of heat transfer time lag, glasses with higher thickness and more distance between two layers of double glazing have better performance (16%) than other types of double glazing. Conclusion: The results of this study can be useful to better understand the thermal behavior of the envelopes, as well as to better designing based on the climatic conditions of Hamadan.

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