Date of Award

Spring 2022

Document Type

Thesis - SCU Access Only

Publisher

Santa Clara : Santa Clara University, 2022.

Department

Mechanical Engineering

First Advisor

Hoyhun Lee

Abstract

The goal of this project is to design and build a functional sunflower preservation system capable of extending the shelf life of sunflowers while providing economic benefit to sunflower farmers. The project was inspired by conversations with an aspiring local sunflower farmer who shared some of the difficulties of entering the market as a small business and transporting harvested sunflowers to stores. Our refrigeration and heat treatment system is designed to increase the shelf life of cut flowers, adding several days to get the flowers to market. Through our design process, we used preliminary experiments, calculations, and SolidWorks simulations to inform our subsystem design and selection. The refrigeration system can be divided up into the following subsystems: an A/C unit controlled by an Arduino and temperature sensors, and the insulated frame of the general structure. The heat treatment system consists of a submersible pump, a storage tank, and a layer of insulation to minimize the amount of heat transfer in the system. The heat treatment bath extends the life of the flowers as they are more able to absorb the hot water than cut flowers. The heated water expands the xylem tubes in the stems and more water is drawn in than otherwise would be. This water is then held in the flower for a longer period of time due to the refrigeration system slowing down the respiration rate of the flowers. This system nets two times longer shelf life than just refrigeration alone. The hot water storage will be heated via the excess heat produced from the A/C unit using a radiator. Our system is capable of reaching and maintaining our target refrigeration temperature of 40˚F and 90˚F for our warm water bath. After construction, our total expenditures amounted to $1800, up to three times lower than other walk-in fridges on the market. Furthermore, our system has a shorter payback period and integrates heat treatment and cold storage for flowers. This project was the successful culmination of nine months of hard work and demonstrates our ability to design, construct, and test a functional flower preservation system.

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