Barrett

Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.

Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.

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Effect of Drought Policies on Los Angeles Water Demand

Description
From 2007 to 2017, the state of California experienced two major droughts that required significant governmental action to decrease urban water demand. The purpose of this project is to isolate and explore the effects of these policy changes on water use during and after these droughts, and to see how…

From 2007 to 2017, the state of California experienced two major droughts that required significant governmental action to decrease urban water demand. The purpose of this project is to isolate and explore the effects of these policy changes on water use during and after these droughts, and to see how these policies interact with hydroclimatic variability. As explanatory variables in multiple linear regression (MLR) models, water use policies were found to be significant at both the zip code and city levels. Policies that specifically target behavioral changes were significant mathematical drivers of water use in city-level models. Policy data was aggregated into a timeline and coded based on categories including user type, whether the policy was voluntary or mandatory, the targeted water use type, and whether the change in question concerns active or passive conservation. The analyzed policies include but are not limited to state drought declarations, regulatory municipal ordinances, and incentive programs for household appliances. Spatial averages of available hydroclimatic data have been computed and validated using inverse distance weighting methods. The data was aggregated at the zip code level to be comparable to the available water use data for use in MLR models. Factors already known to affect water use, such as temperature, precipitation, income, and water stress, were brought into the MLR models as explanatory variables. After controlling for these factors, the timeline policies were brought into the model as coded variables to test their effect on water demand during the years 2000-2017. Clearly identifying which policy traits are effective will inform future policymaking in cities aiming to conserve water. The findings suggest that drought-related policies impact per capita urban water use. The results of the city level MLR models indicate that implementation of mandatory policies that target water use behaviors effectively reduce water use. Temperature, income, unemployment, and the WaSSI were also observed to be mathematical drivers of water use. Interaction effects between policies and the WaSSI were statistically significant at both model scales.
ContributorsHjelmstad, Annika Margaret (Author) / Garcia, Margaret (Thesis director) / Larson, Kelli (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor, Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Passive Thermosyphon Solar Water Heater for Existing Swimming Pool

Description

Water heaters that are manufactured for swimming pools come in several forms, most of which require an electrical input for a source of power. Passive-circulation systems, however, require no electrical power input because fluid circulation occurs as a result of thermal gradients. In solar-based systems, thermal gradients are developed by…

Water heaters that are manufactured for swimming pools come in several forms, most of which require an electrical input for a source of power. Passive-circulation systems, however, require no electrical power input because fluid circulation occurs as a result of thermal gradients. In solar-based systems, thermal gradients are developed by energy collected from sunlight. The combination of solar collection and passive circulation yields a system in which fluids, particularly water, are heated and circulated without need of assistance from external mechanical or electrical sources. The design of such a system was adapted from that of forced-circulation solar collector systems, as were the equations describing its thermodynamic properties. The design was developed based on such constraints as material corrosion resistance, overall system cost, and location-controlled size limitations. The thermodynamic description of the designed system was adjusted on the basis of the designed system’s physical aspects, such as the configuration and material of each component within the solar collector. Numerical analysis performed with the altered thermodynamic equations projected a total energy gain of 7.39 W between 9:00 and 10:00 A.M. and a total energy gain of 13.12 W between 4:00 and 5:00 P.M. The temperature of heated water exiting the collector system was projected to be 17.62°C in the morning and 25.56°C in the afternoon. The morning projection utilized an initial fluid temperature of 12°C and an ambient air temperature of 13°C, while the afternoon projection utilized an initial fluid temperature of 17°C and an ambient air temperature of 22°C. Field testing of the designed passive thermosyphon solar collector system was performed over a period of about one month with one temperature measurement taken at the collector outlet in the morning and another taken in the afternoon. For an ambient air temperature of 13°C, the linear regression developed from the morning dataset yielded an outlet water temperature of 20°C and that for the afternoon dataset yielded an outlet water temperature of 39°C for an ambient air temperature of 17°C. The percentage error between the projected and measured results was 13.51% for the morning period and 52.58% for the afternoon period. Numerical simulation and field data demonstrated that while the collector system operated successfully, its effects were limited to the volume of water immediately surrounding the outlet of the system; the rate of circulation within the system was too low for there to be a meaningful increase in the temperature of the water body at large. The stated results demonstrate that while the particular configuration of passive circulation solar collection technology developed in this instance is capable of transferring solar thermal energy to water without additional energy sources, significant modifications are necessary in order to improve the effectiveness of the technology. Such changes may come from improvements in material availability or alterations to the configuration of components of the collector system.
ContributorsZimmerman, Julia Elizabeth (Author) / Garcia, Margaret (Thesis director) / Phelan, Patrick (Committee member) / Civil, Environmental and Sustainable Eng Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05