scholarly journals Effect of anthropogenic heat sources in the shallow subsurface at city-scale

2020 ◽  
Vol 205 ◽  
pp. 07002
Author(s):  
Monika J. Kreitmair ◽  
Nikolas Makasis ◽  
Asal Bidarmaghz ◽  
Ricky L. Terrington ◽  
Gareth J. Farr ◽  
...  
Keyword(s):  
Heat Fluxes ◽  
Anthropogenic Heat ◽  
Transfer Model ◽  
Heat Sources ◽  
Underground Structures ◽  
Shallow Subsurface ◽  
Subsurface Structures ◽  
Systems Quality ◽  
The Impact ◽  
The City

Rapid rates of urbanisation are placing growing demands on cities for accommodation and transportation, with increasing numbers of basements and tunnel networks being built to meet these rising demands. Such subsurface structures constitute continuous heat sources and sinks, particularly if maintained at comfortable temperatures. At the city-scale, there is limited understanding of the effect of heat exchange of underground infrastructures with their environments, in part due to limited availability of long-term underground temperature data. The effects of underground temperature changes due anthropogenic heat fluxes can be significant, impacting ventilation and cooling costs of underground spaces, efficiency of geo-energy systems, quality and quantity of groundwater flow, and the health and maintenance of underground structures. In this paper we explore the impact of anthropogenic subsurface structures on the thermal climate of the shallow subsurface by developing a heat transfer model of the city of Cardiff, UK, utilising a recently developed semi-3D modelling approach.

A calibrated 3D thermal model of urban heat fluxes into the shallow subsurface

2020 ◽  
Author(s):  
Monika Kreitmair ◽  
Asal Bidarmaghz ◽  
Ricky Terrington ◽  
Gareth Farr ◽  
Ruchi Choudhary
Keyword(s):  
Temperature Data ◽  
Heat Fluxes ◽  
Anthropogenic Heat ◽  
City Centre ◽  
Underground Structures ◽  
Shallow Subsurface ◽  
Limited Availability ◽  
Subsurface Structures ◽  
Thermal Climate ◽  
Urban Heat

<p>The growth of urban populations, combined with the limited availability of above-ground space, is resulting in the increased use of underground structures as living spaces, e.g. residential basements. Such subsurface structures constitute continuous sources and sinks of heat to and from the surrounding underground environment, particularly if maintained at comfortable temperatures. In heavily populated cities and city-centres, underground temperature increases due anthropogenic heat fluxes are well-established, known as the urban underground heat island effect. Due to limited availability of long-term underground temperature data, models looking at subsurface temperature changes caused by man-made structures are difficult to calibrate. However, accurately accounting for the underground thermal climate is essential in ensuring efficient heating and cooling of underground structures as well as correctly estimating the geothermal potential in areas affected by the heat fluxes. The work to be presented explores the impact of temperature-maintained subsurface structures on the thermal climate of the shallow subsurface by developing a 3D finite element model of the Cardiff (UK) city-centre, using COMSOL Multiphysics. The model takes into account conductive and convective heat transfer between the ground and basements as well as geological features and existing hydraulic head measurements. Calibration of the model is performed using time-series temperature data, collected over several years by monitoring boreholes distributed throughout the modelled domain, provided by the British Geological Survey. This constitutes an important step towards accurately characterising the effects of underground urban heat islands and better understanding the human impact on the below ground thermal climate.</p>

scholarly journals City-scale groundwater flow and heat transport modeling in the Milan Metropolitan Area

2020 ◽  
Author(s):  
Alberto Previati ◽  
Giovanni Battista Crosta ◽  
Jannis Epting
Keyword(s):  
Groundwater Flow ◽  
Heat Transport ◽  
Metropolitan Area ◽  
Thermal Regime ◽  
Rural Areas ◽  
Anthropogenic Heat ◽  
Heat Sources ◽  
Thermal Potential ◽  
The Impact ◽  
The City

<p>Aquifers beneath big cities are considered a very important resource from an energy and water supply point of view and are increasingly exploited by means of groundwater extraction wells as well as by shallow open- and closed-loop geothermal systems. Moreover, the shallow subsurface of densely populated cities is increasingly hosting underground infrastructures such as tunnels and building foundations. These activities lead to thermal pollution of the shallow urban underground. This phenomenon has already been documented (urban heat island effect) in many cities worldwide with higher ground/groundwater temperatures in the city centers with respect to surrounding rural areas. The local thermal impact of various underground activities has been studied with analytical and local-scale numerical modeling. However, the resulting groundwater thermal regime at the city-scale is yet mostly unexplored.</p><p>In this work the effects of anthropogenic heat sources and subsurface infrastructures in the Milan metropolitan area is presented. To this aim a groundwater head/temperature monitoring network was established in 2016. Groundwater temperatures in the city center are up to 3°C higher with respect to less urbanized areas. A correlation between the urban density and the groundwater thermal regime was observed. In order to evaluate the spatial variability of the groundwater temperatures, a detailed analysis based on a 3D FEM groundwater flow and heat transport numerical model was carried out by means of the commercial code FeFlow. First, the variability of hydraulic and thermal properties as from borehole logs was spatialized into the model by means of 3D geostatistical techniques to account for aquifer heterogeneities. Complex thermal boundary conditions were assigned to the model including the effects of different land cover/sealing materials, building foundations, tunnels, shallow geothermal wells and the canal network. The thermal transport model was calibrated against high-resolution time-lapse groundwater temperature profiles and continuous measurements at fixed depth.</p><p>The modeling of the current thermal regime of the shallow aquifers was essential to understand the hydrogeological and thermal processes that are relevant at the city scale. The numerical results are a valuable tool to assess the impact of specific heat sources as well as of surface/subsurface infrastructures on the overall thermal regime and to test the long-term thermal potential of ground/groundwater heat exchangers under possible urban development scenarios. Thereby, the proposed approach can support the sustainable development of subsurface infrastructures at the city-scale and the management and assessment of the thermal potential of low enthalpy geothermal resources.</p>

scholarly journals ECOLOGICAL IMPACT ASSESSMENT FOR BUILDING RECONSTRUCTIONS

2021 ◽  
Author(s):  
A.A. Kolpakov ◽  
Keyword(s):  
Impact Assessment ◽  
Negative Impact ◽  
Ecological Impact ◽  
Underground Structures ◽  
Ecological Impact Assessment ◽  
The Impact ◽  
The City

The aim of the work was to analyze the impact on the environment during the reconstruction of buildings. This topic will be of interest to specialists considering the problems of reconstruction of buildings in general. The article assesses the negative impact on the environment of the reconstruction of a children's clinic in the city of Moscow, and also considers the general problems that arise during the reconstruction of buildings and underground structures.

scholarly journals Validation of UWG and ENVI-Met Models in an Abu Dhabi District, Based on Site Measurements

2019 ◽  
Vol 11 (16) ◽  
pp. 4378 ◽  
Author(s):  
Lindita Bande ◽  
Afshin Afshari ◽  
Dina Al Masri ◽  
Mukesh Jha ◽  
Leslie Norford ◽  
...  
Keyword(s):  
Energy Demand ◽  
Mesoscale Model ◽  
Winter Season ◽  
Weather Generator ◽  
Anthropogenic Heat ◽  
Abu Dhabi ◽  
Seasonal Effect ◽  
The Impact ◽  
Urban Weather ◽  
The City

The city of Abu Dhabi is growing every year in population, urban extent and energy demand. This research focuses on the application of two simulation programs to estimate changes in urban climate associated with continued development in Abu Dhabi: The Urban Weather Generator (UWG) and ENVI-met. Simulation with these two software packages are validated with the site data measured in downtown Abu Dhabi. A comparison analysis (in the different seasons) between the rural data, the simulation output, and the site measurements shows the variations of the UHI in this Middle Eastern city and the potential of the validated tools. The main aims of this study are: (a) to make a seasonal validation of the UWG for the city of Abu Dhabi (referring to urban-rural available data). The tool was previously validated for a year (no seasonal division) for Abu Dhabi, Toulouse, Basel, Singapore, Rome and Barcelona. The simulations are based on the 2016 version of the Urban Weather Generator. The analysis is separated into three main seasons (instead of the full year): winter, spring, summer. (b) To make a seasonal validation and improve the second tool evaluated in this study, ENVI-met 4.0. The software can simulate urban temperature, humidity and wind speed. Guides are proposed for the enhancement of the accuracy of both estimation procedures. Referring to the results, UWG tends to overestimate the canyon temperature during the summer and has a more realistic estimation on the winter season. ENVI-met has better estimations of temperatures during the summer season compared to UWG. Finally, the UWG weather file contributes a more detailed energy model on a mesoscale model. It considers the seasonal effect and shows the impact of the climate on profiling the UHI phenomena. ENVI-met needs improvement in calculating the anthropogenic heat and in calculation of the mean radiant temperature.

Numerical Analysis of the Impact of Intensive Underground Structures on Groundwater Flow in Guangzhou (Canton), China

2014 ◽  
Vol 501-504 ◽  
pp. 1832-1845
Author(s):  
Guanyong Luo ◽  
Hong Cao ◽  
Hong Pan
Keyword(s):  
Groundwater Flow ◽  
Underground Structure ◽  
Hydraulic Head ◽  
Underground Structures ◽  
Groundwater Balance ◽  
Darcy Velocity ◽  
Groundwater Environment ◽  
Structure Density ◽  
The Impact ◽  
The City

The soil over the bedrock in the city of Guangzhou is thin, with a depth of only about 11 m. Under such conditions, excessive exploitation of the underground space is very likely to affect the groundwater environment. In this paper, the impact of intensive underground structures, which act as barriers, on the groundwater flow in Guangzhou is investigated. The emphasis is on the impacts in terms of hydraulic head, Darcy velocity and groundwater balance. The study finds that: (1) Under the current underground structure density, the impact on the hydraulic head is small, and most of the change is in the range of ±0.5 m. (2) The Darcy velocity appears to be more susceptible to being affected by the structures. (3) The barrier effect of the intensive structures increases the overflow at the foot of the hills and reduces the transmissivity of the aquifer.

The impact of an urban canopy and anthropogenic heat fluxes on Sydney's climate

2017 ◽  
Vol 37 ◽  
pp. 255-270 ◽  
Author(s):  
Shaoxiu Ma ◽  
Andy Pitman ◽  
Melissa Hart ◽  
Jason P. Evans ◽  
Navid Haghdadi ◽  
...  
Keyword(s):  
Urban Canopy ◽  
Heat Fluxes ◽  
Anthropogenic Heat ◽  
The Impact

Non-Adiabatic Compressor Efficiency of Turbocharger: A Statistical Approach

2010 ◽  
Author(s):  
A. Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Heat Transfer ◽  
Mach Number ◽  
Pressure Ratio ◽  
Heat Fluxes ◽  
Transfer Model ◽  
Compression Process ◽  
Degree Of Confidence ◽  
Temperature Parameter ◽  
The Impact ◽  
Compressor Efficiency

The heat transfer occurring within a turbocharger is closely coupled to the internal combustion exhaust. This process is highly complex and it is not taken account either in the choice of components nor is it reflected in the efficiency maps. In particular the flow within the compressor is usually treated as adiabatic. This is not the case since the heat fluxes from both the turbine and the engine must be taken into account in the compression process. Tests at Imperial College enabled the heat fluxes on a turbocharger installed on a 2.0 litre diesel engine to be quantified. The main aim was to evaluate the heat transfer impact on the compressor efficiency. In addition to this a simplified 1-D model was then developed and validated with experimental measurements. Based on the data generated by the model, a correlation for the compressor non-adiabatic efficiency is presented in the paper. A multiple regression procedure was developed; the work is based on a statistical description of the different parameters that affect the heat transfer model. The regression analysis showed that the compressor non-adiabatic efficiency can be evaluated with good degree of confidence by three main independent parameters: Mach number, pressure ratio and “temperature parameter”. The Mach number had the largest effect on the compressor efficiency, while the temperature factor was revealed to be significant only at low speeds. The impact of the turbocharger size on efficiency was also assessed. The length of the bearing housing and the compressor diameter turned out to be significant within a few percentage points of the compressor efficiency.

On the Impact of Anthropogenic Heat Fluxes on the Urban Boundary Layer: A Two-Dimensional Numerical Study

2010 ◽  
Vol 136 (1) ◽  
pp. 105-127 ◽  
Author(s):  
Andrea Krpo ◽  
Francisco Salamanca ◽  
Alberto Martilli ◽  
Alain Clappier
Keyword(s):  
Boundary Layer ◽  
Numerical Study ◽  
Urban Boundary Layer ◽  
Heat Fluxes ◽  
Anthropogenic Heat ◽  
Two Dimensional ◽  
The Impact

scholarly journals The Impact of Anthropogenic Heat on Formation of Urban Heat Island and Energy Consumption Balance

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
P. Shahmohamadi ◽  
A. I. Che-Ani ◽  
K. N. A. Maulud ◽  
N. M. Tawil ◽  
N. A. G. Abdullah
Keyword(s):  
Energy Consumption ◽  
Urban Heat Island ◽  
Urban Areas ◽  
Natural Ventilation ◽  
Anthropogenic Heat ◽  
Urban Structure ◽  
Heat Island ◽  
Urban Heat ◽  
The Impact ◽  
The City

This paper investigates the impact of anthropogenic heat on formation of urban heat island (UHI) and also determines which factors can directly affect energy use in the city. It explores literally the conceptual framework of confliction between anthropogenic heat and urban structure, which produced UHI intensity and affected energy consumption balance. It then discusses how these two factors can be affected and gives implication to the city and then focuses on whether actions should be taken for balancing adaptation and mitigation of UHI effects. It will be concluded by making the three important strategies to minimise the impact of UHI on energy consumption: landscaping, using albedo materials on external surfaces of buildings and urban areas, and promoting natural ventilation.

The impact of a mega-event on city branding: The European Capital of Culture 2010 and the image of Istanbul

2013 ◽  
Vol 3 (1) ◽  
pp. 29-50 ◽  
Author(s):  
Evinç Doğan ◽  
Ibrahim Sirkeci
Keyword(s):  
Visual Analysis ◽  
Place Branding ◽  
World City ◽  
City Branding ◽  
City Image ◽  
European Capital Of Culture ◽  
National Boundaries ◽  
Symbolic Production ◽  
The Impact ◽  
The City

This study examines the ways in which the city image of Istanbul is re-created through the mega-events within the context of the European Capital of Culture (ECoC) 2010. Istanbul “took the stage” as one of the three ECoC cities (Essen for the Ruhr in Germany and Pécs in Hungary), where the urban spaces were projected as the theatre décor while residents and visitors became the spectators of the events. Organisers and agents of the ECoC 2010 seemed to rebrand Istanbul as a “world city” rather than a “European capital”. With a series of transnational connotations, this can be considered as part of an attempt to turn Istanbul to a global city. In this study we examine posters used during the ECoC 2010 to see whether this was evident in the promoted images of Istanbul. The research employs a hermeneutic approach in which representations, signs and language are the means of symbolic meaning, which is analysed through qualitative methods for the visual data (Visual Analysis Methods), namely Semiotics and Discourse Analysis. The analysed research material comes from a sample of posters released during the ECoC 2010 to promote 549 events throughout the year. Using stratified random sampling we have drawn 28 posters (5% of the total) reflecting the thematic groups of events in the ECoC 2010. Particular attention is also paid to the reflexivity of the researchers and researchers’ embeddedness to the object of research. The symbolic production and visual representation are therefore investigated firstly through the authoritative and historically constituted discourses in the making of Istanbul image and secondly through the orders of cultural consumption and mediatisation of culture through spectacular events. Hence enforcing a transnationalisation of the image of the city where the image appears to be almost stateless transcending the national boundaries. Findings and methodology used in this study can be useful in understanding similar cases and further research into the processes of city and place branding and image relationships. 

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