scholarly journals Investigation of the effects of heat loss through below-grade envelope of buildings in urban areas on thermo-mechanical behaviour of geothermal piles

2020 ◽  
Vol 205 ◽  
pp. 05010
Author(s):  
Maryam Saaly ◽  
Pooneh Maghoul ◽  
Hartmut Holländer
Keyword(s):  
Heat Loss ◽  
Mechanical Behaviour ◽  
Urban Areas ◽  
Energy Demand ◽  
Heat Dissipation ◽  
Mechanical Response ◽  
Pile Head ◽  
Thermal Cycles ◽  
Head Displacement ◽  
Heat Leakage

Harvesting geothermal energy through the use of thermo-active pile systems is an eco-friendly technique to provide HVAC energy demand of buildings. Mechanical behaviour of thermo-active piles is impacted by thermal cycles. Moreover, in urban areas, the temperature of the ground is higher than non-constructed areas due to the heat loss through the below-grade enclosure of buildings. This heat dissipation increases the thermal capacity of the soil and affects the mechanical response of the geothermal pile foundation subjected to thermo-mechanical loading. To investigate the effect of buildings heat loss on thermo-active piles, a numerical thermo-mechanical (TM) analysis was carried out on a proposed energy foundation system for an institutional building, the Stanley Pauley Engineering Building (SPEB) in the campus of the University of Manitoba, Winnipeg, Canada. The mechanical response of the geothermal piles to the thermal cycles with and without considering heat leakage through the basement of the SPEB is compared. Results showed that the cooling loads induced a maximum vertical pile head displacement of -1.18 mm. After 5 years operation of the system, the maximum vertical pile head displacement decreased to -1.05 mm for the case in which heat loss through the basement in considered in the models. In addition, the maximum axial load effective along the pile axis was 6% higher for the case that considers heat loss through the basement compared to the case without considering heat leakage through the building’s below-grade envelope.

scholarly journals Investigation of thermo-mechanical response of a geothermal pile through a small-scale physical modelling

2020 ◽  
Vol 205 ◽  
pp. 05016
Author(s):  
Hussein Hashemi Senejani ◽  
Omid Ghasemi-Fare ◽  
Davood Yazdani Cherati ◽  
Fardin Jafarzadeh
Keyword(s):  
Mechanical Response ◽  
Thermal Response ◽  
Physical Modelling ◽  
Elastic Response ◽  
Small Scale ◽  
Thermal Cycles ◽  
Prolonged Heating ◽  
Excessive Heat ◽  
Head Displacement ◽  
Bed Changes

Energy piles have been used around the world to harvest geothermal energy to heat and cool residential and commercial buildings. In order to design energy geo-structures, thermo-mechanical response of the geothermal pile must be carefully understood. In this paper, a small scale physical model is designed and a series of heating thermal cycles with various vertical mechanical loads are performed. The instrumented pile is installed inside a dry sand bed. Changes in pile head displacement, shaft strains and pile and sand temperatures are monitored using an LVDT, strain gauges and thermocouples, respectively. Prolonged heating cycles, which would continue until boundary temperature changes, would allow the investigation of excessive heat injection when service loads are active on the pile. The thermal response is discussed including confirmation of a temperature influence zone around the pile, the increase in soil temperature, and minimum vertical heat dispersion in the soil. The mechanical response includes plastic settlements when the vertical load passes 20% of ultimate capacity. Plastic settlements have been observed at the half of the capacity reported for the shorter thermal cycles in similar models. The decrease in the capacity indicates a reduction in elastic response of the soil during longer thermal cycles.

scholarly journals Experimental and Numerical Study on the Behavior of Energy Piles Subjected to Thermal Cycles

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Kang Fei ◽  
Di Dai
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Numerical Study ◽  
Heat Transfer Analysis ◽  
Sensitivity Analyses ◽  
Scale Model ◽  
Measured Temperature ◽  
Pile Head ◽  
Thermal Cycles ◽  
Energy Piles

A laboratory-scale model test is conducted to improve the understanding of the effects of thermal cycles on the mechanical behavior of energy piles. The model pile is composed of cement mortar and dry sand with a relative density of 30% is used for the model ground. After applying the working load to the pile head, the pile is subjected to three thermal cycles with a magnitude of 15°C. The measured temperature response and mechanical behavior are analyzed and used to validate the proposed numerical approach. In the numerical analysis, the temperature variation due to thermal cycles is calculated using uncoupled heat transfer analysis. Then, the computed temperature field is used as the boundary condition in the sequence stress analysis. A series of numerical sensitivity analyses are carried out using the sequentially coupled method to investigate the long-term performance of energy piles under different soil and pile head restraint conditions. The numerical results suggest that the restraint condition at the pile head plays an important role in the mechanical response of energy piles. The ultimate pile resistance after thermal cycles does not decrease significantly. The accumulation of settlement of the free head pile and the reduction in the axial force of the restrained head pile should be considered in the design.

Prediction, Testing, and Analysis of a 50 m Long Pile in Soft Marine Clay

2019 ◽  
Vol 13 (2) ◽  
Author(s):  
Bengt Fellenius
Keyword(s):  
Peak Load ◽  
Pile Head ◽  
Marine Clay ◽  
Loading Test ◽  
Head Displacement ◽  
Floating Pile ◽  
Peak Loads ◽  
Static Loading Test ◽  
Beta Coefficient ◽  
Load Movement

On April 4, 2018, 209 days after driving, a static loading test was performed on a 50 m long, strain-gage instrumented, square 275-mm diameter, precast, shaft-bearing (“floating”) pile in Göteborg, Sweden. The soil profile consisted of a 90 m thick, soft, postglacial, marine clay. The groundwater table was at about 1.0 m depth. The undrained shear strength was about 20 kPa at 10 m depth and increased linearly to about 80 kPa at 55m depth. The load-distribution at the peak load correlated to an average effective stress beta-coefficient of 0.19 along the pile or, alternatively, a unit shaft shear resistance of 15 kPa at 10 m depth increasing to about 65 kPa at 50 m depth, indicating an α-coefficient of about 0.80. Prior to the test, geotechnical engineers around the world were invited to predict the load-movement curve to be established in the test—22 predictions from 10 countries were received. The predictions of pile stiffness, and pile head displacement showed considerable scatter, however. Predicted peak loads ranged from 65% to 200% of the actual 1,800-kN peak-load, and 35% to 300% of the load at 22-mm movement.

scholarly journals Electric Mobility in Cities: The Case of Vienna

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 217
Author(s):  
Amela Ajanovic ◽  
Marina Siebenhofer ◽  
Reinhard Haas
Keyword(s):  
Electric Vehicles ◽  
Future Development ◽  
Urban Areas ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Road Transport ◽  
Electric Mobility ◽  
Policy Framework ◽  
The Future ◽  
Historical Developments

Environmental problems such as air pollution and greenhouse gas emissions are especially challenging in urban areas. Electric mobility in different forms may be a solution. While in recent years a major focus was put on private electric vehicles, e-mobility in public transport is already a very well-established and mature technology with a long history. The core objective of this paper is to analyze the economics of e-mobility in the Austrian capital of Vienna and the corresponding impact on the environment. In this paper, the historical developments, policy framework and scenarios for the future development of mobility in Vienna up to 2030 are presented. A major result shows that in an ambitious scenario for the deployment of battery electric vehicles, the total energy demand in road transport can be reduced by about 60% in 2030 compared to 2018. The major conclusion is that the policies, especially subsidies and emission-free zones will have the largest impact on the future development of private and public e-mobility in Vienna. Regarding the environmental performance, the most important is to ensure that a very high share of electricity used for electric mobility is generated from renewable energy sources.

Virtual trabecular bone models and their mechanical response

2008 ◽  
Vol 222 (8) ◽  
pp. 1185-1195 ◽  
Author(s):  
F E Donaldson ◽  
P Pankaj ◽  
A H Law ◽  
A H Simpson
Keyword(s):  
Finite Element ◽  
Trabecular Bone ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Elastic Response ◽  
Anatomical Site ◽  
Virtual Samples ◽  
Micro Level ◽  
Architectural Characteristics

The study of the mechanical behaviour of trabecular bone has extensively employed micro-level finite element (μFE) models generated from images of real bone samples. It is now recognized that the key determinants of the mechanical behaviour of bone are related to its micro-architecture. The key indices of micro-architecture, in turn, depend on factors such as age, anatomical site, sex, and degree of osteoporosis. In practice, it is difficult to acquire sufficient samples that encompass these variations. In this preliminary study, a method of generating virtual finite element (FE) samples of trabecular bone is considered. Virtual samples, calibrated to satisfy some of the key micro-architectural characteristics, are generated computationally. The apparent level elastic and post-elastic mechanical behaviour of the generated samples is examined: the elastic mechanical response of these samples is found to compare well with natural trabecular bone studies conducted by previous investigators; the post-elastic response of virtual samples shows that material non-linearities have a much greater effect in comparison with geometrical non-linearity for the bone densities considered. Similar behaviour has been reported by previous studies conducted on real trabecular bone. It is concluded that virtual modelling presents a potentially valuable tool in the study of the mechanical behaviour of trabecular bone and the role of its micro-architecture.

scholarly journals Indicator-Based Methodology for Assessing EV Charging Infrastructure Using Exploratory Data Analysis

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1869 ◽  
Author(s):  
Alexandre Lucas ◽  
Giuseppe Prettico ◽  
Marco Flammini ◽  
Evangelos Kotsakis ◽  
Gianluca Fulli ◽  
...  
Keyword(s):  
Urban Areas ◽  
Energy Demand ◽  
Energy Use ◽  
Spatial Density ◽  
Carbon Intensity ◽  
Impact Indicator ◽  
Charging Infrastructure ◽  
Smart Charging ◽  
The Impact ◽  
Ev Charging

Electric vehicle (EV) charging infrastructure rollout is well under way in several power systems, namely North America, Japan, Europe, and China. In order to support EV charging infrastructures design and operation, little attempt has been made to develop indicator-based methods characterising such networks across different regions. This study defines an assessment methodology, composed by eight indicators, allowing a comparison among EV public charging infrastructures. The proposed indicators capture the following: energy demand from EVs, energy use intensity, charger’s intensity distribution, the use time ratios, energy use ratios, the nearest neighbour distance between chargers and availability, the total service ratio, and the carbon intensity as an environmental impact indicator. We apply the methodology to a dataset from ElaadNL, a reference smart charging provider in The Netherlands, using open source geographic information system (GIS) and R software. The dataset reveals higher energy intensity in six urban areas and that 50% of energy supplied comes from 19.6% of chargers. Correlations of spatial density are strong and nearest neighbouring distances range from 1101 to 9462 m. Use time and energy use ratios are 11.21% and 3.56%. The average carbon intensity is 4.44 gCO2eq/MJ. Finally, the indicators are used to assess the impact of relevant public policies on the EV charging infrastructure use and roll-out.

Reduction of pile head displacement for restrained-head single pile

2009 ◽  
Vol 13 (3) ◽  
pp. 143-152 ◽  
Author(s):  
Jinoh Won ◽  
Fred H. Kulhawy
Keyword(s):  
Single Pile ◽  
Pile Head ◽  
Head Displacement

scholarly journals A new clustering and visualization method to evaluate urban energy planning scenarios

2018 ◽  
Author(s):  
Sara Torabi Moghadam ◽  
Silvia Coccolo ◽  
Guglielmina Mutani ◽  
Patrizia Lombardi ◽  
Jean Louis Scartezzini ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Urban Areas ◽  
Energy Demand ◽  
Planning Process ◽  
Energy Transition ◽  
Climatic Conditions ◽  
Energy Planning ◽  
Transition Strategies ◽  
Urban Energy ◽  
The City

The spatial visualization is a very useful tool to help decision-makers in the urban planning process to create future energy transition strategies, implementing energy efficiency and renewable energy technologies in the context of sustainable cities. Statistical methods are often used to understand the driving parameters of energy consumption but rarely used to evaluate future urban renovation scenarios. Simulating whole cities using energy demand softwares can be very extensive in terms of computer resources and data collection. A new methodology, using city archetypes is proposed, here, to simulate the energy consumption of urban areas including urban energy planning scenarios. The objective of this paper is to present an innovative solution for the computation and visualization of energy saving at the city scale.The energy demand of cities, as well as the micro-climatic conditions, are calculated by using a simplified 3D model designed as function of the city urban geometrical and physical characteristics. Data are extracted from a GIS database that was used in a previous study. In this paper, we showed how the number of buildings to be simulated can be drastically reduced without affecting the accuracy of the results. This model is then used to evaluate the influence of two set of renovation solutions. The energy consumption are then integrated back in the GIS to identify the areas in the city where refurbishment works are needed more rapidly. The city of Settimo Torinese (Italy) is used as a demonstrator for the proposed methodology, which can be applied to all cities worldwide with limited amount of information.

scholarly journals Impacts of Microclimate Conditions on the Energy Performance of Buildings in Urban Areas

Buildings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 189 ◽  
Author(s):  
Javanroodi ◽  
M.Nik
Keyword(s):  
Urban Areas ◽  
Energy Demand ◽  
Weather Conditions ◽  
Energy Performance ◽  
Urban Morphology ◽  
Weather Data ◽  
Architectural Form ◽  
Energy Performance Of Buildings ◽  
Microclimate Conditions ◽  
The Impact

Urbanization trends have changed the morphology of cities in the past decades. Complex urban areas with wide variations in built density, layout typology, and architectural form have resulted in more complicated microclimate conditions. Microclimate conditions affect the energy performance of buildings and bioclimatic design strategies as well as a high number of engineering applications. However, commercial energy simulation engines that utilize widely-available mesoscale weather data tend to underestimate these impacts. These weather files, which represent typical weather conditions at a location, are mostly based on long-term metrological observations and fail to consider extreme conditions in their calculation. This paper aims to evaluate the impacts of hourly microclimate data in typical and extreme climate conditions on the energy performance of an office building in two different urban areas. Results showed that the urban morphology can reduce the wind speed by 27% and amplify air temperature by more than 14%. Using microclimate data, the calculated outside surface temperature, operating temperature and total energy demand of buildings were notably different to those obtained using typical regional climate model (RCM)–climate data or available weather files (Typical Meteorological Year or TMY), i.e., by 61%, 7%, and 21%, respectively. The difference in the hourly peak demand during extreme weather conditions was around 13%. The impact of urban density and the final height of buildings on the results are discussed at the end of the paper.

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