scholarly journals Modelling climate related performances of building wall coatings and understanding the portability of the “Künzel” rule in different climates

2021 ◽  
Vol 2042 (1) ◽  
pp. 012073
Author(s):  
Andrea Augello ◽  
Joy Alexis Peren ◽  
Heiko Fechner ◽  
Enrico De Angelis
Keyword(s):  
Field Tests ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Water Absorption Coefficient ◽  
Upper Limit ◽  
Hygrothermal Performance ◽  
Building Wall ◽  
German Standard ◽  
Building Physics ◽  
Different Climates

Abstract How may a coating affect the hygrothermal performance of the building envelope in different climates? Years ago, Helmut Künzel, one of the fathers of Building Physics, proposed, a simple, well-known rule, relating two characteristics of a coating: its water absorption coefficient and its vapour diffusion. The “Künzel rule” (and the associated diagram), based on a model confirmed by field tests in the German climate, set an upper limit to both parameters and their product, became a German standard and a practice among experts, practitioners and manufacturers, in many European countries. This paper proposes the results of an analysis aiming to verify its portability in other climates and is based on an extensive simulation of the hygrothermal performances of a reference wall in six different climatic conditions.

Effect of Zeolite Admixture on Freeze/Thaw Resistance of Concrete Exposed to the Dynamic Climatic Conditions

2014 ◽  
Vol 982 ◽  
pp. 27-31 ◽  
Author(s):  
Václav Kočí ◽  
Miloš Jerman ◽  
Jiří Maděra ◽  
Robert Černý
Keyword(s):  
Service Life ◽  
Computational Simulation ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Point Of View ◽  
Freeze Thaw ◽  
Hygrothermal Behavior ◽  
Hygrothermal Performance ◽  
Concrete Building ◽  
Positive Effect

This paper aims at computational simulation of effect of zeolite admixture on service life of concrete building envelope from point of view of freeze/thaw resistance. Hygrothermal behavior of two types of concrete is studied in this paper: reference concrete without any admixtures and zeolite concrete with 40 % zeolite as cement replacement. The computations are performed using computer simulation tool HEMOT, which processes the input parameters using finite element method. The simulation is assumed under dynamic climatic conditions of Prague. As the results of the computational simulations showed, assuming analyzed amount of zeolite, any positive effect of on freeze/thaw resistance was not found related to unprotected building envelope. However, the results indicated, hygrothermal performance of zeolite concrete can be very considerate to applied external layers and thus extend their service life.

scholarly journals Evaluation of the Integration of the Traditional Architectural Element Mashrabiya into the Ventilation Strategy for Buildings in Hot Climates

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 530
Author(s):  
Abdullah Abdulhameed Bagasi ◽  
John Kaiser Calautit ◽  
Abdullah Saeed Karban
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Field Tests ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Indoor Temperature ◽  
Architectural Element ◽  
Cooling Methods

This paper reviewed related research works and developments on the traditional architectural element “mashrabiya” focusing on its history, design and structure, typology, and functions in hot climates. Moreover, the paper assessed the effect of the traditional mashrabiya on the indoor thermal environment and thermal comfort in a selected case study building. For this purpose, two similar rooms were investigated in a selected historic building with abundant mashrabiyas located in the Makkah Region, specifically in Old Jeddah, Saudi Arabia. The field tests were conducted during a typical hot summer month with two different configurations. The study demonstrated that opening the mashrabiya allowed more airflow into the room during the day and reduced the indoor temperature by up to 2.4 °C as compared to the closed mashrabiya. Besides, the building envelope played an important role in preventing the high fluctuation of the indoor air temperature, where the fluctuation of the rooms air temperature ranged between 2.1 °C and 4.2 °C compared to the outdoor temperature which recorded a fluctuation between 9.4 °C and 16 °C. The data presented here can be used for the future development of the mashrabiya concept and the potential incorporation with passive cooling methods to improve its design according to the requirements of modern buildings in hot climates. Moreover, further studies and tests on mashrabiyas under different climatic conditions are required. Also, the different strategies or materials can be incorporated with mashrabiyas in order to improve its thermal performance.

Impact of roof shading on building energy performance in warm & humid climatic places of India

2020 ◽  
pp. 50-64
Author(s):  
Kuladeep Kumar Sadevi ◽  
Avlokita Agrawal
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Energy Performance ◽  
General Assumption ◽  
Climatic Conditions ◽  
Building Envelope ◽  
Passive Cooling ◽  
Base Case ◽  
U Value ◽  
The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

scholarly journals The Impact of Aspect Ratio on External Heat Gain of Multi-storey Office Buildings in Jakarta

2018 ◽  
Vol 16 (1) ◽  
pp. 24-31
Author(s):  
Wasiska Iyati ◽  
◽  
Eryani Nurma Yulita ◽  
Jusuf Thojib ◽  
Heru Sufianto ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Building Design ◽  
Climatic Conditions ◽  
Building Envelope ◽  
External Heat ◽  
Office Buildings ◽  
Office Building ◽  
Cooling Load ◽  
Heat Gain ◽  
The Impact

The narrow land in big cities such as Jakarta, increases the amount of high rise building, especially multi-storey office building. Office building consumes much energy to provide air conditioning to meet the thermal comfort inside the building. On the other hand, the building shape, building envelope, and building orientation to the sun's position are the main factors in building design aspects that affect the amount of cooling load. This study aims to investigate the impact of the aspect ratio or the ratio of the longer dimension of an oblong plan to the shorter, on external heat gain of multi-storey office building. Variables examined include the transparent and solid area of building envelope, the total area of the surface of the building envelope in any orientation, and the volume of the building, as well as the influence of those proportion on the external heat gain. This study uses mathematical calculations to predict the cooling load of the building, particularly external heat gain through the walls, roof and glass, as well as comparative analysis of models studied. The study also aims to generate the design criteria of building form and proportion of multi-storey office buildings envelope with lower external heat gain. In Jakarta climatic conditions, the result on rectangular building plan with aspect ratio of 1 to 4 shows that the external heat gain did not differ significantly, and the smallest heat gain is found on the aspect ratio of 1.8. Results also showed that the greater aspect ratio, the greater reduction of external heat gain obtained by changing the orientation of the longest side facing east-west into the north-south, about 2.79% up to 42.14% on the aspect ratio of 1.1 to 4. In addition, it is known that in same building volume, changing the number of floors from 10 to 50 can improve the external heat gain almost twice.

CREATING A WORKING MODEL OF A DRIVERLESS AIRFIELD TOW TRUCK

2021 ◽  
Vol 2021 (10) ◽  
pp. 45-52
Author(s):  
Denis D'yakov ◽  
Iskander Valiulin ◽  
Dmitriy Lihovidov ◽  
Aleksey Velikanov
Keyword(s):  
Research Methods ◽  
Economic Efficiency ◽  
Experimental Studies ◽  
Field Tests ◽  
Climatic Conditions ◽  
Full Scale ◽  
Support Surface ◽  
Reliable Operation ◽  
Working Model ◽  
Full Scale Tests

The purpose of the research in this paper is to develop a promising airfield driverless tow truck to increase the economic efficiency of aircraft towing facilities, including unmanned aircrafts as well as to ensure reliable operation in various climatic conditions. The research methods include the analysis of the experience of using such driverless airfield tow trucks abroad, the theory of calculating traction and speed indicators and experimental studies conducted during the creation and study of field tests of devices used to load the driving wheels of a tractor. To achieve the goal, the configuration of the structure being designed and its intended composition are determined analytically. The operation of the designed device in the traction mode is considered, and the characteristic of calculating its indicators when moving along the support surface is presented. The presented material briefly illustrates the process from creating a model of a driverless airfield tow truck to the created design of an existing sample, which will later be used to conduct its full-scale tests and a comprehensive assessment of its strength traction and speed characteristics.

Upgrading the Building Facades in Low-Density Residential Areas

2020 ◽  
pp. 216-243
Author(s):  
Katerina Tsikaloudaki ◽  
Dimitra Tsirigoti ◽  
Stella Tsoka ◽  
Theodore Theodosiou
Keyword(s):  
Energy Performance ◽  
Building Envelope ◽  
Building Performance ◽  
Residential Areas ◽  
Energy Needs ◽  
Building Facades ◽  
Thermal Bridging ◽  
Negative Impacts ◽  
Building Physics ◽  
Common Action

The most common action for the buildings' energy upgrade across Europe is the addition of thermal insulation on the external walls. Such interventions, although simple on their construction, cause significant changes on the building's behavior, not only on its energy needs, but also on the hygrothermal and visual performance. The effects are not always positive; for example, thicker insulation may result in lower thermal transmittance and better thermal energy performance, but on the other hand the thermal bridging effect is amplified, and the daylight levels are decreased. This research intends to quantify these impacts by analyzing the relevant parameters for different regions of Europe. The analysis aims at explaining the complicated interrelationships on the building physics' aspects encountered through interventions on the building envelope, but also at identifying appropriate measures that could counterbalance the negative impacts and enhance the overall building performance.

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