Experimental and Life Cycle Analysis of a Solar Thermal Adsorption Refrigeration (STAR) Using Ethanol - Activated Carbon

Date of Award

2018

Degree Name

M.S. in Renewable and Clean Energy

Department

Department of Renewable and Clean Energy

Advisor/Chair

Advisor: Amy Ciric

Second Advisor

Advisor: Jun Ki Choi

Abstract

The off-grid location and unreliable electricity supply to medical clinics in remote parts of India make it difficult to safely store vaccines and other medications using traditional refrigeration systems. The Engineers in Technical Humanitarian Opportunities of Service-learning (ETHOS) program at the University of Dayton, in collaboration with Solar Alternative and Associated Programmes (SAAP) of Patna India, are developing a novel refrigeration system which works on the principle of solar thermal adsorption. This refrigeration system does not require electricity for operation and uses safe, environmentally benign and locally available adsorption pair of ethanol-activated carbon. A bench -scale prototype was developed at the University of Dayton using ethanol-activated carbon as working pair which can generate evaporative temperatures between 2°C and 8°C. The existing horizontally oriented system can achieve targeted refrigeration temperatures (2 - 8°C) during the adsorption cycle and ethanol can be desorbed from the activated carbon during desorption. However, the horizontal geometry inhibited the return of liquid ethanol to the evaporation chamber. A new vertical oriented bench scale system was built to addresses the limitation of the original prototype. The effects of desorption heating temperature, desorption time duration, double activation of activated carbon on evaporative cooling, and possible decomposition of ethanol during desorption were analyzed. Experimental results suggested better desorption happens at elevated temperature (90-125°C) and most of the desorption happens in the first 1-2 hours of heating the adsorbent bed. The high pressure on the evaporator side for multiple adsorption-desorption process, and analysis of GC/MS of desorbed ethanol obtained from the analytical chemist showed possible decomposition of ethanol. The ethanol decomposition prevented multiple cycle operation of the system. The use of double activation technique of the activated carbon helped to achieve as low as -12.7°C evaporator temperature in the first adsorption process. However, no adsorptive cooling was obtained in multiple cycle. However, activated carbon prepared at high temperature 800°C on inert condition showed initial pressure condition on evaporator and activated carbon side after first cycle of adsorption-desorption. This suggest multiple adsorptive cooling can be achieved on multiple cycle operation by using activated carbon prepared at high temperature on inert condition.

Keywords

Alternative Energy, Mechanical Engineering, Materials Science, Chemical Engineering, Chemistry, Energy, Engineering, Climate Change, Environmental Science, Experiments, Renewable Energy, Solar Thermal Energy, Alternative Refrigerator, Solar Thermal Adsorption Refrigeration, Ethanol-Activated Carbon Adsorption Pair, Vaccine Refrigerator, Life Cycle Assesment, Environmental Impact Analysis

Rights Statement

Copyright © 2018, author

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