Mississippi State University
Hodge, K. B.
Date of Degree
Dissertation - Open Access
Doctor of Philosophy (Ph.D)
James Worth Bagley College of Engineering
Department of Mechanical Engineering
Cooling, Heating, and Power (CHP) systems have been around for decades, but systems that utilize 20 kW or less, designated as Micro-CHP, are relatively new. Micro-CHP systems show the most promise for a distributed generation scheme to decentralize the national energy grid. A demonstration site has been constructed at Mississippi State University to show the advantages of these systems. This study is designed to evaluate the performance of a Micro-CHP system and a conventional high-efficiency system. Performance and cost factors can be evaluated for the demonstration site operating under either the CHP system or the conventional system. These results are computed from an energy analysis on collected data. This dissertation introduces a new comparison factor to examine different CHP systems. This new factor is called the System Energy Transfer Ratio (SETR). Other considerations in this study include an extensive literature survey that reviews CHP systems, their components, modeling, and other topics concerning CHP systems operation. In addition, the demonstration facility will be discussed in detail presenting the various components and instrumentation. Furthermore, the energy analysis will be presented, examining the equations used to evaluate the raw data from the demonstration site. An uncertainty analysis will be presented for the experimental results. Raw data was collected for 7 months to present the following results. The combined cycle efficiency from the demonstration site was averaged at 29%. Maximum combined cycle efficiency was evaluated at 58%. The average combined boiler and engine cost, per hour of operation, is shown as $1.8 for heating and $3.9 for cooling. The cooling technology used, an absorption chiller, has been shown to exhibit an average COP of 0.27. The proposed SETR for the demonstration site is 22% and 15%, for heating and cooling, respectively. The conventional high-efficiency system, during cooling mode, was shown to have a COP of 4.7 with a combined cooling and building cost of $0.2/hour of operation. During heating mode, the conventional system had an efficiency of 47% with a fuel and building electrical cost of $0.28/hour of operation.
Giffin, Paxton Keith, "Energy analysis of a Micro-CHP demonstration facility" (2010). Theses and Dissertations. 1872.