Project Director

Shi, Yunye

Department Examiner

Wigal, Cecelia; Margraves, Charles H.

Department

Dept. of Mechanical Engineering

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Florida’s hurricane-prone climate often leaves residents without power and at risk of dangerous indoor heat conditions. This thesis examines whether an off-grid, solar-powered air conditioning system can feasibly maintain safe indoor temperatures over a one-week outage period during peak hurricane season. A simplified, lumped-capacitance thermal model and an energy-based (Coulomb-counting) battery state of charge (SoC) approach were developed in MATLAB to simulate a DC-powered air conditioner (the DC48 unit) in a single-zone space. Historical weather and solar irradiance data from Vero Beach, Florida, represent the hot and humid conditions typical of post-hurricane scenarios. The model uses an on/off plus deadband control strategy to balance comfort against limited solar availability, incorporating conduction, infiltration, internal gains, and solar loads, as well as conservative battery SoC limits (20% minimum and 70% maximum). Results from four scenario cases, varying room size and solar array capacity, indicate that near-ideal comfort (less than 12% of the time above 78 ºF) is achievable when the solar array is matched properly to the cooling demand (e.g., 1.6 kW for a 300 ft2 space). However, undersized arrays or larger enclosures lead to deeper battery depletion and more frequent excursions above the comfort threshold. These findings confirm that aligning solar capacity, battery storage, and cooling load is critical for off-grid air conditioning in disaster relief contexts. This study offers a foundational framework for future experimental validation, more advanced control schemes, and multi-zone expansions that could enhance the resilience and sustainability of emergency cooling solutions in hurricane-prone regions.

Acknowledgments

I would like to begin by expressing my deepest gratitude to my parents for their unwavering support and encouragement throughout my academic journey. Their belief in my abilities has been a constant source of motivation, and I would not have reached this milestone without their love and guidance. I extend my sincere thanks to my thesis committee members for their guidance and expertise. I am grateful to Dr. Yunye Shi, my thesis director, for allowing me the freedom to pursue my interests and for providing steady direction throughout the project. I also appreciate Dr. Cecelia Wigal for going above and beyond with feedback that greatly enriched this research. Finally, I want to thank Dr. Charles Margraves for sharing valuable insights whenever I reached out. Each of you has played a key role in shaping this work. I would also like to acknowledge the assistance provided by ChatGPT, a large language model, developed by OpenAI, that supported me in writing and refining the text in this thesis. All material generated or edited by this tool was carefully reviewed and verified by me to ensure accuracy and integrity. Its help allowed me to focus more of my time on the analytical aspects of my study. Finally, I want to thank my friends, peers, and everyone who offered words of encouragement or helped me navigate the challenges of completing this thesis. Your support and camaraderie have meant more to me than I can adequately express.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2025

Subject

Air conditioning--Hurricane effects--Florida; Electric power systems--Natural disaster effects--Florida; Solar air conditioning--Florida

Keyword

Off-grid cooling;Solar-powered air conditioning;Hurricane resilience;Post-disaster thermal comfort;Florida hurricane season;Feasibility analysis

Discipline

Energy Systems

Document Type

Theses

Extent

vii, 134 leaves

DCMI Type

Text

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by-nc-sa/4.0/

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