Matching Items (232)

Approaches to Study Urban Heat Island – Abilities and Limitations

Description

Urban Heat Island (UHI) has significant impacts on the buildings energy consumption and outdoor air quality (OAQ). Various approaches, including observation and simulation techniques, have been proposed to understand the

Urban Heat Island (UHI) has significant impacts on the buildings energy consumption and outdoor air quality (OAQ). Various approaches, including observation and simulation techniques, have been proposed to understand the causes of UHI formation and to find the corresponding mitigation strategies. However, the causes of UHI are not the same in different climates or city features. Thus, general conclusion cannot be made based on limited monitoring data.

With recent progress in computational tools, simulation methods have been used to study UHI. These approaches, however, are also not able to cover all the phenomena that simultaneously contribute to the formation of UHI. The shortcomings are mostly attributed to the weakness of the theories and computational cost.

This paper presents a review of the techniques used to study UHI. The abilities and limitations of each approach for the investigation of UHI mitigation and prediction are discussed. Treatment of important parameters including latent, sensible, storage, and anthropogenic heat in addition to treatment of radiation, effect of trees and pond, and boundary condition to simulate UHI is also presented. Finally, this paper discusses the application of integration approach as a future opportunity.

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  • 2010-04-11

Prioritizing Urban Sustainability Solutions: Coordinated Approaches Must Incorporate Scale-Dependent Built Environment Induced Effects

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Because of a projected surge of several billion urban inhabitants by mid-century, a rising urgency exists to advance local and strategically deployed measures intended to ameliorate negative consequences on urban

Because of a projected surge of several billion urban inhabitants by mid-century, a rising urgency exists to advance local and strategically deployed measures intended to ameliorate negative consequences on urban climate (e.g., heat stress, poor air quality, energy/water availability). Here we highlight the importance of incorporating scale-dependent built environment induced solutions within the broader umbrella of urban sustainability outcomes, thereby accounting for fundamental physical principles. Contemporary and future design of settlements demands cooperative participation between planners, architects, and relevant stakeholders, with the urban and global climate community, which recognizes the complexity of the physical systems involved and is ideally fit to quantitatively examine the viability of proposed solutions. Such participatory efforts can aid the development of locally sensible approaches by integrating across the socioeconomic and climatic continuum, therefore providing opportunities facilitating comprehensive solutions that maximize benefits and limit unintended consequences.

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  • 2015-06-09

Urban Heat Island Mitigation Strategies: Phoenix

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The growing urban heat island (UHI) phenomenon is having detrimental effects on urban populations and must be addressed in planning. The purpose of this research is to investigate the effectiveness

The growing urban heat island (UHI) phenomenon is having detrimental effects on urban populations and must be addressed in planning. The purpose of this research is to investigate the effectiveness of urban heat island effect reduction factors for Metropolitan Phoenix. Current strategies, case studies, and the ENVI-Met modeling software were used to finalize conclusions and suggestions to further progress Phoenix’s goals in combating urban heat islands. Results from the studies found that the implementation of green walls and roofs, the integration of wind towers into existing and new construction, improving building energy efficiency, and an establishment of a task force responsible for researching applying UHI strategies to the cities are all expected to halt Phoenix’s progression into a more intense UHI, and to reverse the adverse effects that city development has had on the environment.

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  • 2017-04-12

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Data and Predictive Analytics for Energy Use

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The overall energy consumption around the United States has not been reduced even with the advancement of technology over the past decades. Deficiencies exist between design and actual energy performances.

The overall energy consumption around the United States has not been reduced even with the advancement of technology over the past decades. Deficiencies exist between design and actual energy performances. Energy Infrastructure Systems (EIS) are impacted when the amount of energy production cannot be accurately and efficiently forecasted. Inaccurate engineering assumptions can result when there is a lack of understanding on how energy systems can operate in real-world applications. Energy systems are complex, which results in unknown system behaviors, due to an unknown structural system model. Currently, there exists a lack of data mining techniques in reverse engineering, which are needed to develop efficient structural system models. In this project, a new type of reverse engineering algorithm has been applied to a year's worth of energy data collected from an ASU research building called MacroTechnology Works, to identify the structural system model. Developing and understanding structural system models is the first step in creating accurate predictive analytics for energy production. The associative network of the building's data will be highlighted to accurately depict the structural model. This structural model will enhance energy infrastructure systems' energy efficiency, reduce energy waste, and narrow the gaps between energy infrastructure design, planning, operation and management (DPOM).

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  • 2016-12

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Performance Modeling of a Concentrating Photovoltaic Two-Axis Tracker

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The purpose of this research is to study the effect of angle of acceptance and mechanical control system noise on the power available to a two-axis solar concentrating photovoltaic (CPV)

The purpose of this research is to study the effect of angle of acceptance and mechanical control system noise on the power available to a two-axis solar concentrating photovoltaic (CPV) system. The efficiency of a solar CPV system is greatly dependent on the accuracy of the tracking system because a strong focal point is needed to concentrate incident solar irradiation on the small, high efficiency cells. The objective of this study was to evaluate and quantify tracking accuracy for a performance model which would apply to similar two-axis systems. An analysis comparing CPV to traditional solar photovoltaics from an economic standpoint was conducted as well to evaluate the viability of emerging CPV technology. The research was performed using two calibrated solar radiation sensors mounted on the plane of the tracking system, normal to the sun. One sensor is held at a constant, normal angle (0 degrees) and the other is varied by a known interior angle in the range of 0 degrees to 10 degrees. This was to study the magnitude of the decrease in in irradiance as the angle deviation increases. The results show that, as the interior angle increases, the solar irradiance and thus available power available on the focal point will decrease roughly at a parabolic rate, with a sharp cutoff point at angles greater than 5 degrees. These findings have a significant impact on CPV system tracking mechanisms, which require high precision tracking in order to perform as intended.

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  • 2017-05

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Multi-Layer Optical Coatings Composed of Silicon Nanoparticles

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To compete with fossil fuel electricity generation, there is a need for higher efficiency solar cells to produce renewable energy. Currently, this is the best way to lower generation costs

To compete with fossil fuel electricity generation, there is a need for higher efficiency solar cells to produce renewable energy. Currently, this is the best way to lower generation costs and the price of energy [1]. The goal of this Barrett Honors Thesis is to design an optical coating model that has five or fewer layers (with varying thickness and refractive index, within the above range) and that has the maximum reflectance possible between 950 and 1200 nanometers for normally incident light. Manipulating silicon monolayers to become efficient inversion layers to use in solar cells aligns with the Ira. A Fulton Schools of Engineering research themes of energy and sustainability [2]. Silicon monolayers could be specifically designed for different doping substrates. These substrates could range from common-used materials such as boron and phosphorus, to rare-earth doped zinc oxides or even fullerene blends. Exploring how the doping material, and in what quantity, affects solar cell energy output could revolutionize the current production methods and commercial market. If solar cells can be manufactured more economically, yet still retain high efficiency rates, then more people will have access to alternate, "green" energy that does not deplete nonrenewable resources.

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  • 2016-12

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Energy Subsidies: Cheaper Energy or Energy Abuse?

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This paper seeks to analyze the relationship between energy subsidies on fossil fuels by countries and corresponding energy consumption, specifically electricity, by its citizens and occupants. The purpose of this

This paper seeks to analyze the relationship between energy subsidies on fossil fuels by countries and corresponding energy consumption, specifically electricity, by its citizens and occupants. The purpose of this was to determine whether pre-tax subsidies and post-tax subsidies have an effect on that consumption. This paper will discuss the prospect of accounting for post-tax subsidies as a method to curb rampant energy consumption throughout the world, with the focus being on residential electricity use. The two case studies, the Netherlands and Saudi Arabia, will illustrate the consumption patterns in relatively similar economic societies with different subsidy policies. Saudi Arabia will be a high pre-tax subsidy example while the Netherlands will be shown to account for some of the post-tax subsidies through an externality tax system. At the end of this analysis, this paper will show that the heavy subsidization of electricity production is strongly correlated to residential electricity consumption at levels that many officials would deem unsustainable, and that as such, subsidy reform is both beneficial and necessary.

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  • 2016-12

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Building Management System Integration: Energy Data Analytics

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This paper describes the research done to quantify the relationship between external air temperature and energy consumption and internal air temperature and energy consumption. The study was conducted on a

This paper describes the research done to quantify the relationship between external air temperature and energy consumption and internal air temperature and energy consumption. The study was conducted on a LEED Gold certified building, College Avenue Commons, located on Arizona State University's Tempe campus. It includes information on the background of previous studies in the area, some that agree with the research hypotheses and some that take a different path. Real-time data was collected hourly for energy consumption and external air temperature. Intermittent internal air temperature was collected by undergraduate researcher, Charles Banke. Regression analysis was used to prove two research hypotheses. The authors found no correlation between external air temperature and energy consumption, nor did they find a relationship between internal air temperature and energy consumption. This paper also includes recommendations for future work to improve the study.

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  • 2018-05

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Have Government Subsidies Improved Corportate Performance in New Energy Industry? An Analysis Based On Empirical Analysis and Case Study of GCL-Poly

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This paper investigates the effect of government subsidies on the performance of new energy companies. An empirical analysis using data from Chinese A-share listed new energy firms and companies of

This paper investigates the effect of government subsidies on the performance of new energy companies. An empirical analysis using data from Chinese A-share listed new energy firms and companies of other industries under standard classification of industries by China Securities and Regulatory Commission and a case study of GCL-Poly are combined. The result shows that government subsidies have negative effects on new energy companies' performance and their R&D intensity.

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  • 2017-12

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Optimal Dimensions for Beam Power Harvester for Maximum Power Output

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In the last several years, there has been a significant growth in research in the field of power harvesting, the process of capturing the energy surrounding a system and converting

In the last several years, there has been a significant growth in research in the field of power harvesting, the process of capturing the energy surrounding a system and converting it into usable electrical energy. This concept has received particular interest in recent years with the ever-increasing production of portable and wireless electronic devices. Many of these devices that are currently in production utilize electrochemical batteries as a power source, which while effective, maintain the drawback of having a finite energy supply, thus requiring periodic replacement. The concept of power harvesting, however, works to solve these issues through electronics that are designed to capture ambient energy surrounding them convert it into usable electronic energy. The use of power harvesting in energy scavenging devices allows for the possible development of devices that are self-powered and do not require their power sources to be replaced. Several models have been developed by Soldano et al [3] and Liao et al [2] that have been proven accurate at predicting the power output of a piezoelectric power harvester in a cantileaver beam configuration. The work in this paper will expand further on the model developed by Liao et al [2], and as its main goal will use a modified form of that model to predict the optimal dimensions for a beam power harvester to achieve the maximum power output possible. The model will be updated b replacing the mode shape function used to approximate the deflection of the beam with the true defletion, which is based on the complex wavenumber that incorporates the complex Young's modulus of the material used. Other changes to account for this replacement will also be presented, along with numerical results of the final model.

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  • 2012-05