Degree Type

Dissertation

Date of Award

1993

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

First Advisor

Howard Shapiro

Abstract

Home refrigerators are the largest consumers of electricity among household appliances, consuming an estimated 7% of the total electricity used in the United States;As a result of the NAECA and Montreal Protocol, refrigerator/freezer manufacturers and researchers are presently searching for more efficient refrigerator/freezer designs which utilize non-CFC refrigerants. Recent studies show that the gasket area heat gain may account for as much as 21% of the total thermal load in refrigerator/freezer. Also, study shows that HFC-134a, the most likely replacement of CFC-12, is immiscible with mineral oil and may result in slightly higher energy consumption as a drop-in replacement;The purpose of this research was to investigate, both experimentally and theoretically, total gasket gain (gasket infiltration and conduction heat gain) and the effects of HFC-134a on energy consumption of refrigerator/freezers. This research presents the results of an extensive literature review, interviews with refrigerator/freezer and gasket manufacturers, experimental and theoretical evaluation of gasket infiltration and heat gain. This study showed that only 2% of total load in a refrigerator/freezer is due to gasket infiltration and the total load due to gasket heat gain is only 5%. These amounts are undoubtedly less significant than the amount that has been claimed by either literature or the refrigerator/freezer manufacturers;Also included is a description of the experimental evaluation of HFC-134a as a replacement for CFC-12 in a typical top mount refrigerator/freezer. Different capillary tube lengths and different HFC-134a charges were investigated. The data showed that energy consumption using HFC-134a was slightly lower relative to the CFC-12 based unit. Optimum capillary pressure drop and HFC-134a charge levels were also determined.

DOI

https://doi.org/10.31274/rtd-180813-9709

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Majid Ghassemi

Language

en

Proquest ID

AAI9321148

File Format

application/pdf

File Size

95 pages

Share

COinS