Degree Type

Dissertation

Date of Award

1996

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

First Advisor

Howard N. Shapiro

Abstract

Many energy conservation projects have been implemented, and a great deal of investment will be made in the future. Yet little data are available showing the actual energy savings achieved. This project evaluated energy conservation projects related to compressors, boilers, and reducing heating and cooling loads, through monitoring at six industrial facilities and in on-campus facilities;As predicted by theory, lowering the exit pressure from the air compressor resulted in lower power consumption for positive displacement compressors. For the screw compressor studied, the isentropic compression model does a good job of predicting the savings due to a decreased compressor exit pressure. For the evaluated reciprocating compressor, the isentropic compression model overpredicted the savings unless the model was modified to account for the effects of clearance;Literature predicts that lowering the compressor inlet air temperature will decrease the power consumption. Contrary to what is in the literature, data and theoretical analysis show that it is not power consumption that decreased by lowering the intake temperature, but the compressor run time. Due to the fact that it is the run time, and not the power consumption that is decreased, energy will be saved by using outside air for compressor intakes only if the compressor cycles;Theory states that as the combustion efficiency increases, the fuel usage of a boiler will decrease. Due to measurement uncertainty, the calculated energy savings can be exceeded by its uncertainty. As long as a boiler is operating within suggested ranges, efforts should be made to decrease the steam generation rate. This project also provides data showing that contrary to common practice, it may not be appropriate to approximate boiler efficiency using combustion efficiency;This project evaluated a system designed to reduce cooling loads, and one designed to reduce heating loads. Due to poor design, these systems did not save as much energy as expected. When designing systems to reduce heating and cooling loads, one must understand the purpose of the system and interactions between the system and surroundings, else one may purchase systems that are inappropriate and may actually increase energy costs.

DOI

https://doi.org/10.31274/rtd-180813-10452

Publisher

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

Copyright Owner

Karen Louise Smith

Language

en

Proquest ID

AAI9712605

File Format

application/pdf

File Size

194 pages

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