Cycle-Based Vapor Cycle System Control and Active Charge Management for Dynamic Airborne Applications 2014-01-2224

Numerous previous studies have highlighted the potential efficiency improvements which can be provided to aircraft thermal management systems by the incorporation of vapor cycle systems (VCS), either in place of, or in conjunction with, standard air cycle systems, for providing the needed thermal management for aircraft equipment and crews. This paper summarizes the results of a cycle-based VCS control architecture as tested using the Vapor Cycle System Research Facility (VCSRF) in the Aerospace Systems Directorate of the Air Force Research Laboratory at Wright-Patterson Air Force Base. VCSRF is a flexible, dynamic, multi-evaporator VCS which incorporates electronic expansion valves and a variable speed compressor allowing the flexibility to test both components and control schemes. The goal of this facility is to reduce the risk of incorporating VCS into the thermal management systems (TMS) of future advanced aircraft.

In this paper, the authors discuss the hardware configuration, as well as the differences between a baseline control architecture (consisting of evaporator superheat and system capacity control) and the suggested cycle-based control. It will highlight some of the implications of the practical constraints on the control schemes. In addition, an active charge management (ACM) system was implemented as part of the VCSRF; initial data showing the efficiency improvements enabled by this system are also presented.