Development of a Shipboard Modular Refrigeration System Using Carbon Dioxide as the Refrigerant

The Department of the Navy (Navy) has identified the development of a CO2-based shipboard modular refrigeration system for chilled food storerooms and freeze food storerooms as an important way of ensuring they are prepared for regulations and potential supply chain challenges that could arise from international phase out the refrigerants currently used in these applications. Specifically, the Navy is looking for compact 0.75 rTons and 1.5rTons MRSs designed for subcritical and transcritical operation. The designed MRSs should be capable of operating at temperatures between 41oF (5oC) and 33oF (-0.6oC) for chilled food storerooms and 0oF (-17.8oC) and -4oF (-20oC) for freeze food storerooms using 44oF (6.7oC) chilled water for condenser cooling.ÝIn response to the above technical challenge, CTS plans to partner with Leonardo DRS and its Marlo Heat Transfer Solutions line of business, the market leader in Navy combatant HVAC & R equipment, firefighting and electronics cooling solutions. Together CTS and DRS plan to build off of the current DRS equipment currently using conventional refrigerants, specifically, the fully-qualified 0.75 Ton version of the MRS which has 0.75 Ton (2.6kW) refrigeration at freeze conditions, and 1.0 Ton (3.5kW) refrigeration at chill conditions. CTS plans to use in-house developed transcritical CO2 models to design a new CO2 refrigeration system within the space constraints of the existing DRS-Marlo MRS. Components will then be sourced and a prototype system mocked up and tested in breadboard lab configuration and later within the existing MRS itself (Phase I option or Phase II) depending on timing and specific component availability. ÝCreative Thermal Solutions, Inc. (CTS) has vast experience designing, prototyping, and testing the performance of CO2 systems across a wide range of industries and applications. Specifically, CTS has developed CO2 systems for a number of DOD applications including mobile systems such as Environmental Control Units (ECUs), platforms such as the High Mobility Multipurpose Wheeled Vehicle (HMMWV), and Multi-Temperature Refrigerated Container Systems (MTCRS). CTS and DRS Marlo have established a proven framework for related HVAC&R DOD efforts via collaboration in the past yielding first of its kind, production ready, CO2 ECUs for military applications.