EXPERIMENTAL ASSESSMENT OF A NOVEL DUAL OPENING DEWAR FOR USE ON A LIQUID AIR ENERGY STORAGE SYSTEM INSTALLED ON REMOTE, ISLANDED, RENEWABLE MILITARY MICROGRIDS

Islanded, renewable energy microgrids for use at remote Department of Defense (DOD) facilities reduce logistical burdens associated with fossil fuel–based electrical power sources and provide greater operational flexibility; however, energy generation can be intrinsically intermittent on these microgrids. This intermittent electrical generation can be mitigated with energy storage. Liquid air energy storage (LAES) is one promising technology proposed to meet this energy storage issue due to its high energy density. Small-scale microgrids may not have enough excess capacity to store pressurized liquid air (LA), and instead may rely on unpressurized LA storage and their associated unpressurized power recovery options. Using commercial off-the-shelf components, this thesis conducts a comparative tradespace study for a variety of dual opening, unpressurized Dewar designs for use with Stirling- or Peltier-based power recovery cycles. The dual opening design is found to not be efficacious for short-term storage necessary for microgrid use due to excessive conductive losses to the outer Dewar shell; however, the design may be useful as an LA receiver and immediate-use energy storage medium for a connected Stirling generator. A proposed alternative solution using Dewar self-pressurization for LA storage and transport for DOD microgrid applications is presented for future work.Outstanding ThesisLieutenant Commander, United States NavyApproved for public release. Distribution is unlimited

Experimental Assessment of a Novel Dual Opening Dewar for Use on a Liquid Air Energy Storage System Installed on Remote, Islanded, Renewable Microgrids

Islanded, renewable energy microgrids for use at remote operating facilities reduce logistical burdens associated with fossil fuel based electrical power sources and provide greater operational flexibility; however, energy generation can be intrinsically intermittent on renewable microgrids. This intermittent electrical generation can be mitigated with electrical energy storage. Liquid air energy storage (LAES) is one promising technology proposed to meet this energy storage issue due to its high energy density and lack of geographical constraints. Small-scale microgrids may not have enough excess capacity to store pressurized liquid air (LA), and instead may rely on unpressurized LA storage and their associated unpressurized power recovery systems. Using commercial off-the-shelf components, this article conducts a performance-based tradespace study for several dual opening, unpressurized Dewar designs for use with Stirling- or Peltier-based power recovery cycles. The dual opening Dewar design is found to be ineffective for the short-term LA storage times necessary for small-scale microgrid use, primarily due to excessive conductive thermal losses; however, the design may be useful as a LA receiver and immediate use energy storage medium for a connected Stirling generator. A proposed alternative solution using a self-pressurized Dewar for LA storage and transport for microgrid applications is presented for future work