Durham School of Architectural Engineering and Construction


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A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Architectural Engineering, Under the Supervision of Professor Mingsheng Liu. Lincoln, Nebraska: August, 2011

Copyright 2011 Xiangnan Shi


A large amount of the primary energy consumed in the US is derived from the built environment followed by energy consumed in the transportation and industrial sectors. Consequently, improving the energy efficiency of buildings is an important part of ensuring a more sustainable world for future generations. Of the various techniques employed to improve the energy efficiency of buildings, commissioning and retrofits continue to be the most widely applied solutions. Control optimization, mainly imbedded with continuous commissioning so far, is not applied as widely. Even though there are currently a few applications that integrate all three techniques, no comparison has been made between the integrated process and conventional process. The objective of this research is thus to conduct such a comparison.

This thesis begins with a review of the applications for commissioning, retrofits, and control optimization of existing buildings. Then, to compare the conventional commissioning and retrofit process with integrated process, a case demonstration is applied to an existing small commercial building.

Study results indicate that in this existing commercial building, conventional retrofits should not be implemented without commissioning because of long simple payback period. The integrated process is more cost effective than conventional process. It can achieve Net Present Value (NPV) of 251,390$ during a 20-years span, which is 2.82 times of commissioning-only process and 1.62 times of combined commissioning and retrofits process.

Adviser: Mingsheng Liu