Matching Items (5)
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- All Subjects: environment
- All Subjects: Mechanical Engineering
Description
When air is supplied to a conditioned space, the temperature and humidity of the air often contribute to the comfort and health of the occupants within the space. However, the vapor compression system, which is the standard air conditioning configuration, requires air to reach the dew point for dehumidification to occur, which can decrease system efficiency and longevity in low temperature applications.
To improve performance, some systems dehumidify the air before cooling. One common dehumidifier is the desiccant wheel, in which solid desiccant absorbs moisture out of the air while rotating through circular housing. This system improves performance, especially when the desiccant is regenerated with waste or solar heat; however, the heat of regeneration is very large, as the water absorbed during dehumidification must be evaporated. N-isopropylacrylamide (NIPAAm), a sorbent that oozes water when raised above a certain temperature, could potentially replace traditional desiccants in dehumidifiers. The heat of regeneration for NIPAAm consists of some sensible heat to bring the sorbent to the regeneration temperature, plus some latent heat to offset any liquid water that is evaporated as it is exuded from the NIPAAm. This means the NIPAAm regeneration heat has the potential to be much lower than that of a traditional desiccant.
Models were created for a standard vapor compression air conditioning system, two desiccant systems, and two theoretical NIPAAm systems. All components were modeled for simplified steady state operation. For a moderate percent of water evaporated during regeneration, it was found that the NIPAAm systems perform better than standard vapor compression. When compared to the desiccant systems, the NIPAAm systems performed better at almost all percent evaporation values. The regeneration heat was modeled as if supplied by an electric heater. If a cheaper heat source were utilized, the case for NIPAAm would be even stronger.
Future work on NIPAAm dehumidification should focus on lowering the percent evaporation from the 67% value found in literature. Additionally, the NIPAAm cannot exceed the lower critical solution temperature during dehumidification, indicating that a NIPAAm dehumidification system should be carefully designed such that the sorbent temperature is kept sufficiently low during dehumidification.
To improve performance, some systems dehumidify the air before cooling. One common dehumidifier is the desiccant wheel, in which solid desiccant absorbs moisture out of the air while rotating through circular housing. This system improves performance, especially when the desiccant is regenerated with waste or solar heat; however, the heat of regeneration is very large, as the water absorbed during dehumidification must be evaporated. N-isopropylacrylamide (NIPAAm), a sorbent that oozes water when raised above a certain temperature, could potentially replace traditional desiccants in dehumidifiers. The heat of regeneration for NIPAAm consists of some sensible heat to bring the sorbent to the regeneration temperature, plus some latent heat to offset any liquid water that is evaporated as it is exuded from the NIPAAm. This means the NIPAAm regeneration heat has the potential to be much lower than that of a traditional desiccant.
Models were created for a standard vapor compression air conditioning system, two desiccant systems, and two theoretical NIPAAm systems. All components were modeled for simplified steady state operation. For a moderate percent of water evaporated during regeneration, it was found that the NIPAAm systems perform better than standard vapor compression. When compared to the desiccant systems, the NIPAAm systems performed better at almost all percent evaporation values. The regeneration heat was modeled as if supplied by an electric heater. If a cheaper heat source were utilized, the case for NIPAAm would be even stronger.
Future work on NIPAAm dehumidification should focus on lowering the percent evaporation from the 67% value found in literature. Additionally, the NIPAAm cannot exceed the lower critical solution temperature during dehumidification, indicating that a NIPAAm dehumidification system should be carefully designed such that the sorbent temperature is kept sufficiently low during dehumidification.
ContributorsKocher, Jordan Daniel (Author) / Wang, Robert (Thesis advisor) / Phelan, Patrick (Committee member) / Parrish, Kristen (Committee member) / Arizona State University (Publisher)
Created2019
Description
This project is focused on local scale sustainability. The goal is to understand the impact of small unsustainable actions of people, and hopefully create a change in their habits. The focus was plastic usage, such as the use of water bottles, grocery bags, or even the packaging that our food and other products typically come in. Plastic has become an integral part of lives, where we do not even think of our actions as we stuff our leftover grocery bags in its designated drawer. My goal throughout this project was to guide people to an environmentally conscious lifestyle by increasing the likelihood of recycling on the ASU campus. I created an interactive informative presentation that focused on recycling and preventing plastic and unwanted trash from ending up in landfills and oceans. The presentation was given to a small group of participants along with two surveys. There was a survey provided before the presentation to gauge a participant's present recycling habits then there was a survey that was given some time after the presentation to track if certain recycling habits had changed due to the presentation. The post presentation survey did report that there were changes to some of the participants' recycling habits. The research provides suggestions to help increase recycling and waste prevention based off surveys that were widely distributed on campus. The top three suggestions that would help make recycling more prevalent on campus are: education on the subject, more accessibility to recycling bins, and creating an incentive program.
ContributorsVazquez, Juliana Evone (Author) / Parrish, Kristen (Thesis director) / Burke, Rebekah (Committee member) / Civil, Environmental and Sustainable Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Building information modeling (BIM) has already sparked changes in design and construction practices, ranging from new methods to coordinate work during design to supporting paperless construction sites where crews use handheld devices in lieu of paper plans. It is seen as the starting point for the larger picture, virtual design and construction (VDC). While some research has explored the feasibility of using BIM for Facilities Management (FM) this practice is yet to become widely accepted and integrated. This paper explores how VDC could improve the operations of a Facilities Management department at a large state university. Specifically, the authors examine the degree to which institutional requirements foster BIM use during building operations, the ability of models to interface with existing FM software, and the willingness of FM executives to incorporate BIM into their processes. The authors also discuss the sorts of information contained in building models that FM could find most useful, and highlight those pieces of information required for FM that many building models do not contain. Finally, the paper closes with a set of recommendations about how to create building models that more seamlessly integrate into existing Facilities Management processes at the university studied, in order to draw a set of recommendations that may apply more broadly to state universities and similar institutions.
ContributorsHebel, Natasha Faith (Author) / Parrish, Kristen (Thesis director) / Ayer, Steven (Committee member) / Del E. Webb School of Construction (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
An Earned Value Management System (EVMS) is an organization’s system for project/program management that integrates a defined set of associated work scopes, schedules and budgets, allowing for effective planning, performance, and management control. A mature EVMS that is compliant with standards and guidelines, and that is applied in a positive social environment is critical to the overall success of large and complex projects and programs. However, a comprehensive and up-to-date literature review revealed a lack of a data-driven and consistent rating system that can gauge the maturity and the environment surrounding EVMS implementation. Therefore, the primary objective of this dissertation focuses on the EVMS maturity and environment, and investigates their impact on project performance. The author was one of the 41 research team members whose goal was to develop the novel rating system called Integrated Project/Program Management (IP2M) Maturity and Environment Total Risk Rating (METRR). Using a multi-method research approach, the rating system was developed based on a literature review of more than 600 references, a survey with 294 responses, focus group meetings, and research charrettes with more than 100 subject matter experts from the industry. Performance data from 35 completed projects and programs representing over $21.8 billion in total cost was collected and analyzed. The data analysis showed that the projects with high EVMS maturity and good EVMS environment outperformed those with low maturity and poor environment in key project performance measures. The contributions of this work includes: (1) developing definitions for EVM, EVMS and other research related terms, (2) determining the gaps in the EVMS literature, (3) determining the EVMS state of the practice in the industry, (4) developing a scalable rating system to measure the EVMS maturity and environment, (5) providing quantified evidence on the impact of EVMS maturity and environment on project performance, and (6) providing guidance to practitioners to gauge their EVMS maturity and environment for an enhanced project and program management integration and performance.
ContributorsAramali, Vartenie Mardiros (Author) / Gibson Jr., George Edward (Thesis advisor) / El Asmar, Mounir (Committee member) / Parrish, Kristen (Committee member) / Arizona State University (Publisher)
Created2022
Description
Arizona has been rapidly expanding in both population and construction over the last 20 years, and with the hot summer climate, many homeowners experience a significant increase in their utility bills. The cost to reduce these energy bills with home renovations can become expensive. This has become increasingly apparent over the last few years with the impact that covid had on the global supply chain. Prices of materials and labor have never been higher, and with this, the price of energy continues to increase. Therefore, it is important to explore methods to make homes more energy-efficient without the price tag. In addition to benefitting the homeowner by decreasing the cost of their monthly utility bills, making homes more energy efficient will aid in the overall goal of reducing carbon emissions.
ContributorsFiller, Peyton (Author) / Phelan, Patrick (Thesis director) / Parrish, Kristen (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2022-05