U.S. patent application 20180045432 (applicant Rolls-Royce Corp., Indianapolis, Ind.):
"A thermal management system includes a closed dynamic cooling circuit, and a closed first steady-state cooling circuit. Each circuit has its own compressor, heat rejection exchanger, and expansion device. A thermal energy storage (TES) system is configured to receive a dynamic load and thermally couple the dynamic cooling circuit and the first steady-state cooling circuit. ... TES is a heat exchanger that includes a TES material such as wax or other material that can store energy, including via a phase change material which, as known in the art, stores and releases energy at a phase change temperature while changing phase from, for instance, a liquid to a solid."