Improving thermal performance of building walls by optimizing insulation layer distribution and thickness for same thermal mass

2011 ◽  
Vol 88 (9) ◽  
pp. 3113-3124 ◽  
Author(s):  
Sami A. Al-Sanea ◽  
M.F. Zedan
Keyword(s):  
Thermal Performance ◽  
Thermal Mass ◽  
Insulation Layer ◽  
Building Walls

scholarly journals Investigation of the Thermal Performance of Energy Tunnel Equipped with the Insulation Layer Considering Ventilation and Groundwater Seepage

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guozhu Zhang ◽  
Ziming Cao ◽  
Xu Zhao ◽  
Yongli Xie ◽  
Xiaohua Liu ◽  
...  
Keyword(s):  
Heat Exchange ◽  
Groundwater Flow ◽  
Exchange Rates ◽  
Thermal Performance ◽  
Surrounding Rock ◽  
Interface Temperature ◽  
Insulation Layer ◽  
Groundwater Seepage ◽  
Ground Heat Exchangers ◽  
Reduction Effect

The insulation layer is usually installed in the tunnel structure, whereas the influence of the insulation layer on the thermal behavior of energy tunnel ground heat exchangers (GHEs) is rarely investigated. The model tests were performed in this study to evaluate the heat transfer potential of the energy tunnel with the insulation layer under ventilation and groundwater seepage. The results can be obtained as follows: first, the fluctuations of air temperature and surrounding rock temperature at different locations are relevant to insulation layer, ventilation, and groundwater seepage. Second, the reduction effect of ventilation on the interface temperature of tunnel lining and surrounding rock is alleviated when using an insulation layer, and the interface temperature at upstream section of groundwater seepage is more easily affected by the energy tunnel GHEs. Third, the variation range of ground temperature is wider at the downstream section of groundwater flow. Moreover, the heat exchange rates of tunnel without the insulation layer improve by 5.82% and 6.45% with increasing wind speed at two groundwater flow velocities of 1 × 10 − 4 and 5 × 10 − 4  m/s, and there are only 2.03% and 0.77% enhancements of heat exchange rates by ventilation for the tunnel with the insulation layer. However, the thermal performance of the energy tunnel improved by groundwater is less relevant to the existence of the insulation layer. The relevant findings can provide an effective guidance for the following research and design of the energy tunnel.

scholarly journals The Effects of Courtyards on the Thermal Performance of a Vernacular House in a Hot-Summer and Cold-Winter Climate

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1042 ◽  
Author(s):  
Shimeng Hao ◽  
Changming Yu ◽  
Yuejia Xu ◽  
Yehao Song
Keyword(s):  
Solar Radiation ◽  
Thermal Performance ◽  
Natural Ventilation ◽  
Field Measurements ◽  
Ground Level ◽  
Active Role ◽  
Thermal Mass ◽  
Cold Winter ◽  
Winter Climate ◽  
Climate Zones

Achieving comfort in hot summer and cold winter (HSCW) climate zones can be challenging, since the climate is characterized by high temperatures in the summer and relatively colder temperatures in the winter. Courtyards, along with other semi-open spaces such as verandas and overhangs, play an important role in mitigating outdoor climate fluctuations. In this research, the effects of courtyards on the thermal performance of vernacular houses in HSCW climate zones were studied via field measurements and computational fluid dynamics (CFD) models. The selected courtyard house was a representative vernacular timber dwelling situated in the southeast of Chongqing, China. The indoor and outdoor air temperature measurements revealed that the courtyard did play an active role as a climatic buffer and significantly reduced the temperature’s peak value in the summer, while during the winter, the courtyard prevented the surrounding rooms from receiving direct solar radiation, and thus to some extent acted as a heat barrier. The contributions of thermal mass are quite limited in this area, due to insufficient solar radiation in winter and general building operations. The natural ventilation mechanism of courtyard houses in HSCW zones was further studied through CFD simulations. The selected opened courtyard was compared to an enclosed structure with similar building configurations. The airflow patterns driven by wind and buoyancy effects were first simulated separately, and then together, to illustrate the ventilation mechanisms. The simulation results show that the courtyard’s natural ventilation behavior benefited from the proper openings on ground level.

scholarly journals User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

2020 ◽  
Vol 12 (22) ◽  
pp. 9672
Author(s):  
Mamdooh Alwetaishi ◽  
Ashraf Balabel ◽  
Ahmed Abdelhafiz ◽  
Usama Issa ◽  
Ibrahim Sharaky ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
High Altitude ◽  
Air Temperature ◽  
Thermal Performance ◽  
Indoor Air ◽  
Computer Modelling ◽  
Evaporative Cooling ◽  
Comfort Level ◽  
Thermal Mass ◽  
The Impact

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.

scholarly journals Thermal Performance Impacts of Venting EIFS Assemblies

2021 ◽  
Author(s):  
Khaled H. Khaled
Keyword(s):  
Thermal Performance ◽  
Percentage Reduction ◽  
Insulation Layer ◽  
Building Height ◽  
Wind Speeds ◽  
Maximum Reduction ◽  
The Face ◽  
Wind Velocities

One of the key improvements in EIFS is the addition of a geometrically defined drainage gap in the continuous insulation layer to allow water that has penetrated the outer EIFS lamina to drain out by gravity to the exterior. The integration of this cavity has raised questions regarding its impact on the thermal performance of wall assemblies constructed with these vented EIFS. The objective of this research is to evaluate the thermal performance impacts, as a percentage reduction in the effective RSI-Value, of a vented EIFS assembly against a face-sealed EIFS and expand the results with respect to increased building height and wind velocities. It can be concluded from the results that a vented EIFS assembly with 2-inches of EPS foam insulation and 4-inches of fiberglass cavity insulation experiences a maximum reduction of 4% in the whole assembly’s effective RSI-value against a face-sealed EIFS assembly. Furthermore, increased wind speeds, caused by installing EIFS at higher elevations from the grade had negligible effects on the thermal resistances of the face-sealed and vented EIFS

scholarly journals THE INFLUENCE OF THERMAL RESISTANCE AND THERMAL MASS ON THE SEASONAL PERFORMANCE OF WALLING SYSTEMS IN AUSTRALIA

2015 ◽  
Vol 10 (4) ◽  
pp. 107-126 ◽  
Author(s):  
Dariusz Alterman ◽  
Adrian W. Page ◽  
Behdad Moghtaderi ◽  
Congcong Zhang ◽  
Trevor Moffiet
Keyword(s):  
Thermal Resistance ◽  
Thermal Performance ◽  
Thermal Mass ◽  
New Approach ◽  
Comfort Levels ◽  
Building Enclosures ◽  
Seasonal Performance ◽  
Brick Veneer ◽  
R Value ◽  
Time Required

This paper describes an experimental investigation of the thermal performance of four Australian domestic walling systems (cavity brick, insulated cavity brick, insulated brick veneer and insulated reverse brick veneer) having various combinations of thermal insulation and of thermal mass location within the wall. This experimental analysis extends further the previous studies of the benefits of thermal mass on the overall thermal performance of building enclosures (Gregory et al. 2008, Luo at al. 2008, Alashaary et al. 2009). The comparison is based on the time required to maintain thermal comfort for free-floating internal conditions. The results clearly show that internal comfort levels are influenced by both the thermal resistance of the walls as well as the extent and location of the thermal mass, with neither parameter being the sole predictor. The best thermal performance is therefore obtained by an appropriate combination of thermal mass and resistance, rather than focussing on the overall wall thermal resistance (R-value) alone. A new approach of density temperature plots for comparison of temperature variation is also used in the assessment of module thermal performance.

Comparative Analysis of the Use of Thermal Insulation Materials Depending on Climatic Conditions and Comfort Microclimate Supply Systems

2022 ◽  
Vol 906 ◽  
pp. 99-106
Author(s):  
Siranush Egnatosyan ◽  
David Hakobyan ◽  
Spartak Sargsyan
Keyword(s):  
Energy Efficiency ◽  
Comparative Analysis ◽  
Thermal Insulation ◽  
Thermal Performance ◽  
Climatic Conditions ◽  
Insulation Material ◽  
Insulation Layer ◽  
Transfer Resistance ◽  
Insulation Materials ◽  
Wide Range

The use of thermal insulation materials to reduce the heating and cooling demand of the building in order to provide energy efficiency is the main solution. But there is a wide range of these products on the market and, therefore, the choice and application of these materials is a rather difficult task, since many factors must be taken into account, such as environmental safety, cost, durability, climatic conditions, application technology, etc. Basically, comfort microclimate systems are designed based on normative standards, where the thickness of the thermal insulation material is selected depending on the required heat transfer resistance. These values are calculated taking into account climate conditions, that is the duration of the heating period, as well as taking into account sanitary and hygienic requirements. This article discusses the thermal performance of building materials, and also provides a comparative analysis of the use of thermal insulation materials depending on climatic factors and on the system providing comfort microclimate. Based on the calculations by mathematical modeling and optimization, it is advisable to choose the thickness of the thermal insulation, taking into account the capital and operating costs of the comfort microclimate systems. Comparing the optimization data with the normative one, the energy efficiency of the building increases by 50-70% when applying the optimal thickness of the thermal insulation layer, and when the thermal insulation layer is increased, the thermal performance of the enclosing structures has improved by 30%, which contributes to energy saving.

scholarly journals Experimental Study on Thermal Performance of Externally Insulated Walls of Intermittent Air-Conditioned Rooms in Summer in Hot Summer and Cold Winter Region, China

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Yong Ding ◽  
Lu Xu ◽  
Baizhan Li ◽  
Xiaoqing Liu
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Thermal Process ◽  
Heat Dissipation ◽  
Distribution Characteristics ◽  
Cold Winter ◽  
Night Time ◽  
Heat Transfer Theory ◽  
Heat Preservation ◽  
Building Walls

Now requirements for the thermal performance of building walls are based on the assumption that heat flux transfers in one direction through the wall. However, in Hot Summer and Cold Winter Region of China, the direction of heat flow in the wall not only changes with the seasons, but also changes in the same period of using. In this paper, dynamic thermal process of externally insulated walls in different air-conditioner’s running state in summer in Chongqing, China, was tested. The distribution characteristics of the outdoor and indoor air temperature and the surface and inner temperatures of the wall were analyzed and demonstrated. Based on the unsteady-state heat transfer theory, the study calculated and analyzed the distribution characteristics of the direction of the heat flux in the thermal process. Also the characteristics of insulation and heat preservation for walls under different air-conditioner’s running state were analyzed. It is shown that, in any air-conditioner’s running state, the direction of the heat flux through the wall is obviously dynamically changing. There is obvious difference in the thermal performance needs of the wall; that is, it has strong demand for thermal insulation in daytime and strong demand for heat dissipation during night time in summer.

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