Control strategy: wind energy powered variable chiller with thermal ice storage

• Main Author: Boonyobhas, Rex A.
• Other Authors: Gannon, Anthony J.
• Published: Monterey, California: Naval Postgraduate School 2015
• Online Access: http://hdl.handle.net/10945/44525

Approved for public release; distribution is unlimited === This study commissioned a variable speed chiller system powered by renewable energy with ice thermal storage. A control strategy was also developed that matched the chiller load to any available renewable power. These solutions will allow the Department of Defense to move away from the traditional, electrical-focused, energy storage methods such as batteries to targeted solutions for large energy uses, specifically cooling. This research required developing a SOFtware program to extract data from a micro-grid. In order to effectively use intermittent renewable power, the researcher created a control algorithm for operating the variable speed chiller, and used a monitoring system to match the load to the power production. The data demonstrated that wind energy at the Turbopropulsion Laboratory was intermittent and decreased from summer to fall. The study also created a model to simulate a three-blade vertical-axis wind turbine and compared the results to similar published data. The ANSYS CFX simulation results showed that the NACA0018 blade profile best matched the published result, and was thus selected for additional turbulence modeling. At speeds less than or equal to 10 m/s, the best turbulence for modeling the turbine was the shear stress transport model; at speeds greater than 10 m/s, standard k-epsilon provided the closer correlation.