scholarly journals Evaluating the impact of different pipe arrangements on the thermal performance of thermo-active piles

2020 ◽  
Vol 205 ◽  
pp. 05006
Author(s):  
Ryan Y. W. Liu ◽  
Eleonora Sailer ◽  
David M. G. Taborda ◽  
David M. Potts
Keyword(s):  
Thermal Performance ◽  
Energy Use ◽  
Near Field ◽  
Heat Fluxes ◽  
Far Field ◽  
Low Carbon ◽  
Finite Element Analyses ◽  
Heating And Cooling ◽  
The Impact ◽  
Evolution With Time

Thermo-active piles are widely utilised for low carbon heating and cooling, and their uses are further encouraged in cities where there are obligations for developments larger than a certain threshold to generate a portion of their estimated energy use on site in a renewable manner. It is therefore important to model accurately the thermal performance of the designed thermo-active piles to ensure that such obligations are complied with. In this paper, the thermal performance of a thermo-active pile is quantified by the evolution with time of the power that can be harnessed from the pile, obtained from 3D thermo-hydro-mechanically coupled finite element analyses which include the simulation of a hot fluid flowing through heat exchanger pipes. Different pipe arrangements are considered in this study, in order to demonstrate the potential gains in efficiency arising from the installation of multiple U-loops within the pile. Furthermore, detailed analysis of the heat fluxes resulting from pipe-pile-soil interaction is carried out, illustrating the contribution of the different components of the system (concrete, near-field and far-field) to the overall storage of thermal energy.

scholarly journals Numerical computation for the impact of pantograph angles on the near-field and far-field aerodynamic noises of pantographs

2017 ◽  
Vol 19 (8) ◽  
pp. 6471-6484 ◽  
Author(s):  
Jia Wei Tan ◽  
Bin Bai ◽  
Xiang Yu Xu ◽  
Xiao Lei Yang
Keyword(s):  
Numerical Computation ◽  
Near Field ◽  
Far Field ◽  
The Impact

scholarly journals Energy Security Problem amid Global Energy Transition

2021 ◽  
Vol 21 (4) ◽  
pp. 772-784
Author(s):  
Yury V. Borovsky
Keyword(s):  
Energy Security ◽  
Energy Use ◽  
Rapid Development ◽  
Energy Transition ◽  
The United States ◽  
Low Carbon ◽  
Security Threat ◽  
The Us ◽  
The Impact ◽  
The Eu

In the early 2020s the worlds transition from carbon-intensive to climate-neutral energy use has already become a discernible and a difficult-to-reverse process. With Joe Bidens election as US president, the United States have returned to the Paris Climate Agreement and have become a key driver of this process (along with the EU and China). As a result, the international community has reached a consensus on the ongoing energy transition. This process will require considerable effort and may take several decades. Nevertheless, the impact of energy transition on traditional approaches to energy security, which emerged largely as a result of the global oil crises of the 1970s and 1980s and are centered around the supply of fossil fuels, is already a relevant research topic. This problem is examined relying on the relevant terminological, theoretical and factual material. The article concludes that energy transition will ultimately undermine the carbon paradigm that has underpinned energy security policies since the 1970s. Rapid development of renewable and other low-carbon energy sources will certainly remove key energy security risks of energy importers and, possibly, allow them to achieve energy independence. However, a post-carbon era may also generate new risks. For countries that rely heavily on oil, gas and coal exports, energy transition will result in the loss of markets and revenues. It may present an energy security threat for them as well as it will require a costly and technologically complex process of the energy sector decarbonization. Some exporters, especially those with high fuel rents and insufficient financial reserves, may face serious economic and social upheavals as a result of energy transition. The EU and the US energy transition policies reflect provisions of all three fundamental international relations theoretical paradigms, including realism. This means that the EU and the US policy, aimed at promoting climate agenda, may be expected to be rather tough and aggressive. China as the third key player in energy transition is still following a liberal course; however, it may change in the future.

scholarly journals Progress towards the realization of an optical Far-Field Superlens

2021 ◽  
Author(s):  
◽  
Farzaneh Fadakar Masouleh
Keyword(s):  
Zinc Oxide ◽  
Near Field ◽  
Diffraction Gratings ◽  
Evanescent Waves ◽  
Field Pattern ◽  
Far Field ◽  
Potential Candidate ◽  
Plasmonic Material ◽  
Far Field Pattern ◽  
The Impact

<p>Conventional optics suffer from a fundamental resolution limit due to the nature of light. The near-field superlens concept was introduced two decades ago, and its theory for enabling high resolution imaging is well-established now. Initially, this superlens, which has a simple setup, became a hot topic given the proposition of overcoming the diffraction limit. It has been demonstrated that a near-field superlens can reconstruct images using evanescent waves emanating from small objects by means of resonant excitations on the surface of the superlens. A modified version of the superlens named the far-field superlens is theorized to be able to project the near-field subwavelength information to the far-field region. By design, the far-field superlens is a near-field superlens with nanostructures added on top of it. These nanostructures, referred to as diffraction gratings help couple object information available in the evanescent waves to the far-field. Work reported in this thesis is divided to two major sections. The first describes the modelling technique that investigates the performance of a far-field superlens. This section focuses on evaluating the impact of the diffraction gratings geometry and the object size on the far-field superlens performance as well as the resulting far-field pattern. It was shown that a far-field superlens with a nanograting having a duty cycle of 40% to 50% produces the maximum intensity and contrast in the far-field interactions. For periodic rectangular objects, an inverse-trapezoidal nanograting was shown to provide the best contrast and intensity for far-field interactions. The minimal simulation domain to model a symmetric far-field superlens design was determined both in 2D and 3D. This input reduced the required modelling time and resources. Finally, a 3D far-field superlens model was proposed, and the effect of light polarization on the far-field pattern was studied. The second section of this thesis contains the experimental study that explores a new material as a potential candidate for the construction of far-field superlens. The material conventionally used for superlens design is silver, as its plasmonic properties are well-established. However, scaling down silver features to the nanoscale introduces fundamental fabrication challenges. Furthermore, silver oxidizes due to its reactions with sulphur compounds at ambient conditions, which means that operating a silver far-field superlens is only possible in a well-controlled environment. This disagrees with our proposed concept of a low-cost and robust superlens imaging device. On the other hand, highly doped semiconductors are emerging candidates for plasmonic applications due to the possibility of tuning their optical and electrical properties during the fabrication process. While the working principle of a superlens is independent of the plasmonic material of choice, every plasmonic material has a particular range of operating wavelengths. The pros and cons of each plasmonic material are usually identified once used experimentally. In this work, aluminium-doped zinc oxide was the proposed material of choice for the far-field superlens design. The second part of this thesis details the characterization results of the optical, electrical and structural properties of this proposed alternative. Our aluminium-doped zinc oxide samples were highly transparent for large parts of the spectrum. Their carrier concentration was of the order of 10+20 cm-3, and a resistivity of about 10-3 Ω.cm was achieved. The modelled dielectric permittivity for the studied samples showed a cross-over frequency in the near-infrared region, with the highest plasma frequency achieved in this study being 4710 cm-1.</p>

scholarly journals A Complementary Approach to Traditional Energy Balances for Assessing Energy Efficiency Measures in Final Uses: The Case of Space Heating and Cooling in Argentina

2020 ◽  
Vol 12 (16) ◽  
pp. 6563
Author(s):  
Roque G Stagnitta ◽  
Matteo V Rocco ◽  
Emanuela Colombo
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Primary Energy ◽  
Embodied Energy ◽  
Space Heating ◽  
Output Analysis ◽  
Final Energy ◽  
Heating And Cooling ◽  
Energy Balances ◽  
The Impact

Energy balances have been historically conceived based on a supply-side perspective, providing neither detailed information about energy conversion into useful services nor the effects that may be induced by the application of policies in other sectors to energy consumption. This article proposes an approach to a thorough assessment of the impact of efficiency policies on final energy uses, focusing on residential space heating and cooling, and capable of: (1) quantifying final useful services provided and (2) accounting for the global impact of efficiency policies on final energy use, taking advantage of Input–Output analysis. This approach is applied in five cities of Argentina. Firstly, the quantity of energy service provided (i.e., level of thermal comfort) for each city is evaluated and compared with the defined target. It is found out that heating comfort is guaranteed approximately as established, whereas in the cooling case the provision is twice the established level. Secondly, primary energy consumption of heating and cooling services is evaluated before and after different efficiency improvement policies. The results show that the major primary energy saving (52%) is obtained from the upgrading appliances scenario and reflect the importance of accounting for embodied energy in goods and services involved in interventions.

Vibration Propagation Law and Control Test of Ultra Soft Soil Ground under Impact Load

2013 ◽  
Vol 295-298 ◽  
pp. 2030-2033
Author(s):  
Zhang Ming Li ◽  
Wen Xiu Zeng
Keyword(s):  
Impact Load ◽  
Soft Soil ◽  
Near Field ◽  
Far Field ◽  
Horizontal Distance ◽  
Negative Power ◽  
Propagation Law ◽  
Safe Control ◽  
The Impact ◽  
Control Distance

Through in situ tests on the impact vibration of a typical muck ground treatment major project directed by the first author, the vibration propagation law under the impact load for the ultra soft soil ground is obtained, and quantitative environmental safe control distance on the vibration influence is also gained. The main results are the two aspects. (1) The attenuation law of both level and vertical peak vibration acceleration with the horizontal distance can be described well by the negative power function; and the ground vibrations caused by tamping impact can be distinguished between two types, i.e. near-field and far-field. Near-field tamping vibration influence is confined to a small range of the tamping center, which decays obviously faster than the one of far-field. (2) The radius of influence of tamping vibration depends not only on the tamping energy but also the soil type. Loose, slightly dense soft soil has a larger energy absorption capacity and a smaller effect radius of tamping vibration than the dense and hard soil; and the vibration safe control distance is determined as 27.3m in the tests according to the safe boundary determined code of industrial and civil architecture in China.

scholarly journals Exploring the Impact of a District Sharing Strategy on Application Capacity and Carbon Emissions for Heating and Cooling with GSHP Systems

2020 ◽  
Vol 10 (16) ◽  
pp. 5543
Author(s):  
Yi Zhang ◽  
He Qi ◽  
Yu Zhou ◽  
Zhonghua Zhang ◽  
Xi Wang
Keyword(s):  
Carbon Emissions ◽  
Urban Areas ◽  
District Heating ◽  
Low Carbon ◽  
Heating And Cooling ◽  
Ground Source ◽  
Sharing Strategy ◽  
Low Carbon Energy ◽  
The Impact

To meet long-term climate change targets, the way that heating and cooling are generated and distributed has to be changed to achieve a supply of affordable, secure and low-carbon energy for all buildings and infrastructures. Among the possible renewable sources of energy, ground source heat pump (GSHP) systems can be an effective low-carbon solution that is compatible with district heating and cooling in urban areas. There are no location restrictions for this technology, and underground energy sources are stable for long-term use. According to a previous study, buildings in urban areas have demonstrated significant spatial heterogeneity in terms of their capacity to demand (C/D) ratio under the application of GSHP due to variations in heating demand and available space. If a spatial sharing strategy can be developed to allow the surplus geothermal capacity to be shared with neighbors, the heating and cooling demands of a greater number of buildings in an area can be satisfied, thus achieving a city with lower carbon emissions. In this study, a GSHP district system model was developed with a specific embedding sharing strategy for the application of GSHP. Two sharing strategies were proposed in this study: (i) Strategy 1 involved individual systems with borehole sharing, and (ii) Strategy 2 was a central district system. Three districts in London were selected to compare the performance of the developed models on the C/D ratio, required borehole number and carbon emissions. According to the comparison analysis, both strategies were able to enhance the GSHP application capacity and increase the savings of carbon emissions. However, the improvement levels were shown to be different. A greater number of building types and a higher variety in building types with larger differentiation in heating and cooling demands can contribute to a better district sharing performance. In addition, it was found that these two sharing strategies were applicable to different kinds of districts.

Effect of Frame-Restoring Force Characteristics on the Pounding Response of Multiple-Frame Bridges

2005 ◽  
Vol 21 (4) ◽  
pp. 1113-1135 ◽  
Author(s):  
Susendar Muthukumar ◽  
Reginald DesRoches
Keyword(s):  
Ground Motions ◽  
Near Field ◽  
Hysteretic Behavior ◽  
Impact Response ◽  
Far Field ◽  
Restoring Force ◽  
Bridge Model ◽  
Multiple Frame ◽  
The Impact ◽  
Force Characteristics

This study examines the effect of column hysteretic behavior on the impact response of adjacent frames in multiple-frame bridges. A simplified planar analytical bridge model is developed including inelastic frame action, nonlinear hinge behavior, and abutment effects. Pounding is simulated using a stereomechanical approach. The frame hysteretic models considered include the elasto-plastic and bilinear (traditional), Q-Hyst (stiffness-degrading), and pivot hysteresis (strength-degrading) models. Analytical studies conducted on adjacent bridge frames reveal that the traditional models underestimate the stiff frame displacement amplification due to pounding, and overestimate the flexible frame displacement amplification, when compared with other hysteretic models. A stiffness-degrading model is recommended to accurately estimate the pounding response of bridge frames subjected to far-field ground motion. The use of a strength-degrading model increases the stiff frame displacement amplification by 125% when compared to the stiffness-degrading model for highly out-of-phase frames, and is recommended in the presence of near-field ground motions.

Current and future test reference years at a 5 km resolution

2019 ◽  
Vol 41 (4) ◽  
pp. 389-413
Author(s):  
C Liu ◽  
W Chung ◽  
F Cecinati ◽  
S Natarajan ◽  
D Coley
Keyword(s):  
Energy Use ◽  
Computer Modelling ◽  
Weather Data ◽  
Energy Estimates ◽  
Low Carbon ◽  
Practical Applications ◽  
Climate Resilience ◽  
Building Simulations ◽  
The Uk ◽  
The Impact

Frequently, the computer modelling of the natural and human-made environment requires localised weather files. Traditionally, the weather files are based on the observed weather at a small number of locations (14 for the UK). Unfortunately, both the climate and the weather are known to be highly variable across the landscape, so the small number of locations has the potential to cause large errors. With respect to buildings, this results in incorrect estimates of the annual energy use (sometimes by a factor of 2), or of overheating risk. Here we use a validated weather generator running on a 5 × 5 km grid to create probabilistic test reference years (pTRYs) for the UK at 11,326 locations. We then investigate the spatial variability of these pTRYs and of annual energy estimates and temperatures in buildings generated by them, both now and in 2080. Further pTRYs targeted at understanding the impact of minimum and maximum temperatures are proposed and produced at the same locations. Finally, we place these pTRYs, which represent the first set of reference weather files at this spatial resolution in the world and that include the urban heat island effect, into a publicly accessible database so researchers and industry can access them. Practical applications: Insufficiently localised weather data for building simulations have limited the accuracy of previous estimations of energy use and overheating risk in buildings. This work produces localised probabilistic test reference years (pTRYs) across the whole UK for now and future climates. In addition, a new pTRY method has been proposed in order to overcome an unexpected shortcoming of traditional pTRYs in representing typical maximum and minimum temperatures. These current and future weather data will be of interest to various disciplines including those interested in low carbon design, renewable energy and climate resilience.

Impact of Shape on Building Energy Use in Tunisia

Solar Energy ◽  
2006 ◽  
Author(s):  
Kais Ouertani ◽  
Moncef Krarti
Keyword(s):  
Energy Use ◽  
Residential Buildings ◽  
Energy Performance ◽  
Analysis Tool ◽  
Architectural Form ◽  
Relative Compactness ◽  
Building Shape ◽  
Heating And Cooling ◽  
Building Form ◽  
The Impact

This paper investigates the impact of the architectural form on the energy performance of residential buildings in Tunisia. A relative compactness is defined as one indicator of a building shape. The results of the analysis indicate that a significant decrease in heating and cooling energy requirements can be obtained by minimizing the relative compactness of detached residential houses. A simplified analysis tool, suitable for early design process, is developed to assess the impact of building form on its energy performance for several cities in Tunisia.

Sign in / Sign up

Export Citation Format

Share Document