Multi-Evaporator Loop Thermal Storage (MELTS)

This proposal introduces the multi-evaporator loop thermal storage (MELTS) system for increasing F-35 capability during extreme thermal missions where component failure is expected. The MELTS system comprises of a fuel and/or PAO primary loop with a two phase loop technology, phase change material (PCM) condenser, and a PCM freeze loop to freeze the PCM while the fuel/PAO is cold. The freeze loop allows cooling to temperatures the initial cold fuel/PAO temperature instead of the maximum allowable PAO/fuel temperature. This lower temperature provides additional cooling capacity when needed. The MELTS system is scalable and can be sized to meet or exceed the 5 kW transport and 2.5 kW-hr (9 MJ) energy storage requirements. The goals of Phase 1 include defining parameters, such as heat loads, operating temperatures, etc., necessary for the F-35 aircraft cooling system, creating analytical models, carrying out research, and refining the MELTS concept. During the Phase 1 option period, testing of various components of the system will be carried out. This includes testing to minimize PCM condenser weight, and to configure evaporators for thermal coupling to the fuel/PAO and components. Phase 2 will include fabrication of a subscale MELTS system.