Date of Completion
Honors College Thesis
Energy Systems, Energy Hub, Climate Change, Energy, UVM Physical Plant
Due to the aging power system, increase in energy demand, dependency on limited fossil resources, and climate change there is significant need in the future for a restructured power system. It is essential for the new power grid to bring together the concepts of distributed micro grids as well as synergy between multiple energy carriers to increase the reliability and economics of the system. One way to model the new network is to use the idea of an energy hub where a local system contains distributed and renewable generation and integrated multi-carrier energy sources. The benefits of utilizing the energy hub as a modeling framework include reduced energy prices and demand for consumers as well as reduced peak demand for the local distribution companies. This project models and analyzes the UVM’s campus energy system using energy hubs and Matlab simulations, which together form the energy tool called “Hubert”. Various what-if simulations with modification to the current system are run in Hubert to find ways to increase energy efficiency and reduce the associated cost of the UVM energy system.
The three main modifications to the current system which are simulated are the addition of an electric chiller, a combined heat and power generator, and a chilled water thermal energy storage tank. The total cost of generation for the current UVM energy system was simulated to be $37,361.01 for a winter day and $23,717.62 for a summer day. The system with an electric chiller and chilled water storage saw a savings of $365 for the summer simulation but no saving for the winter since there is no cooling load. The payback period analysis on this system showed that it would take 31.45 years to pay off the assets. When the system with a cogeneration unit is compared with the current UVM system the savings are $18,748.70 for the winter simulation and $11,633.30 for the summer simulation. The payback period analysis on this system showed that it would take 3.57 years to pay off the new CHP unit. Finally if all three new assets are installed the savings would be $18,748.70 for the winter and $13,300.00 for the summer. The payback period analysis on this system showed that it would take 3.79 years to pay off the assets.
Demand charges were added to the daily cost of generation by averaging the estimated monthly on-peak and off-peak electric peaks over the appropriate hours. Calculations found that current UVM’s cost of generation with demand costs raised the costs to $53,240.05 and $43,234.18 for winter and summer days, respectively. For the system with the CHP unit, the summer daily cost of generation with demand charges is $19,526.90, however, this cost spiked up to $20,685.15 or $30,442.60 if the CHP unit failed during off-peak or on-peak hours, respectively.
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Botkin-Levy, Micah, "Modeling and Analysis of UVM's Campus Energy System with Energy Hubs" (2015). UVM Honors College Senior Theses. 83.