All ETDs from UAB

Advisory Committee Chair

Robert W Peters

Advisory Committee Members

Ashraf Z Al-Hamdan

Ian E Hosch

Jason T Kirby

Hessam Taherian

Document Type

Dissertation

Date of Award

2017

Degree Name by School

Doctor of Philosophy (PhD) School of Engineering

Abstract

Energy conservation has been a hot topic worldwide since the energy crisis occurred in the 1970s that the realization natural energy resources will be consumed in the future. With the rapid growth of population and urbanization, the energy demand is increasing annually. Due to the increasing energy demand, the cost of energy will likely continue to increase and fluctuate at higher prices, leading to large financial pressure, not only to the industry, but also to educational institutions and households. The air conditioning system is an important component for domestic and nondomestic buildings that requires a large amount of energy and contributes to the peak electricity consumption and utility bill. This research used a transient system simulation program (TRNSYS) to simulate and analyze the energy conservation potential of a modified air conditioning system, which employs preheat tanks and chilled water tanks (CHWT), in an effort to achieve energy conservation opportunities in selected buildings at the University of Alabama at Birmingham (UAB), which is located in a hot and humid climate region in the southeastern United States. The preheat tank was employed to both recover wasted heat and to reduce the temperature of cooling water entering the cooling tower for the purpose of lowering electricity consumption and improving the coefficient of performance (COP). The water in the preheat tank can be used for lavatory purposes and as a water supplement for the central boiler. The chilled water tank was set up to moderate the energy consumption during peak hours in an effort to reduce operating expenses. The baseline utility model was verified by comparison with actual utility bills. The incorporation of a chilled water system effectively shifted energy during peak hours to off-peak hours. The thermal storage system slightly impacted the COP of the chiller. A water-cooled chiller tends to have better energy savings and improvement of the COP than an air-cooled chiller under the same operation conditions of employing the CHWT. The reduction in energy use varies with different system designs, operation, and capacity was proven. Because of this, environmental benefits can be achieved. The payback period analysis, including capital investment and cost savings resulting from energy conservation showed that thermal storage is not feasible for implementation due to the low electricity rates and high investment costs.

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Engineering Commons

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