Session: 06-09 Advanced Simulation & Testing

Paper Number: 123714

123714 - Design and Commissioning of the IRIS: A Setup for Aircraft Vapour Compression Cycle-Based Environmental Control System Testing 

Greenhouse gas emissions from the aviation sector are responsible for 3.5% of net anthropogenic effective radiative forcing. After the COVID-19 pandemic, air traffic has resumed its growth and emissions are expected to double or even triple in the coming 30 years. Therefore, the aeronautical sector is investing many resources in the development of novel and sustainable technologies for the next generation of more electric aircraft. The goal is the reduction of passenger aircraft environmental footprint by electrifying the aircraft non-propulsive subsystems, currently counting for almost 5% of the total specific fuel consumption. The Environmental Control System (ECS) is the auxiliary system responsible for cabin air pressurization, passengers thermal comfort, and avionics cooling. It is the main consumer of non-propulsive energy, accounting for 3% of the total energy consumption among all the aircraft subsystems. The traditional ECS is based on the Air Cycle Machine (ACM) technology, i.e., a reverse Joule cycle. The efficiency and the environmental footprint of the ECS can be arguably improved by recurring to an electrically-driven Vapour Compression Cycle (VCC) system for cabin cooling.

To contribute to research in this field, a novel experimental test rig, called Inverse organic Rankine cycle Integrated System (IRIS), has been designed and commissioned at the Propulsion & Power Laboratories of the TU Delft Aerospace faculty. The setup has been conceived for testing the performance of VCC systems for aircraft ECS applications in different operating conditions, and for validating the numerical models developed for the system simulations. The facility consists of a single-stage compression refrigeration cycle and accommodates two test sections: a volumetric compressor testing setup and an air-cooled condenser test bed. The evaporator is heated by a glycol-water mixture, warmed up in an independent loop. An electronic expansion valve controls the degree of superheating of the refrigerant vapour at the compression suction port. The design working fluid is the low-GWP refrigerant R-1233zd(E), which represents an alternative to the state-of-the-art R-134a. The system is designed for a cooling capacity of 15.5 kW.

This work documents the detailed design and the commissioning of the IRIS setup. The design requirements and the selection criteria of the system configuration and the working fluid are illustrated. The choice of hardware, measurement instrumentation and control procedures is reported in relation to the objectives of the future experimental campaigns. The commissioning of the facility is documented by discussing the data recorded during operation at steady-state at the design operating point, together with the operation of the setup during start-up and the shut-down procedures. The design operating condition corresponds to a temperature of evaporation equal to 20 °C and a temperature lift between condensation and evaporation of 45 °C. For this operating point, the piston compressor reaches a pressure ratio equal to 4.15 with a refrigerant mass flow rate of 0.11 kg/s. The values of temperature and pressure are measured at all the relevant state points of the thermodynamic cycle, with a relative average uncertainty generally lower than 0.7%.

Presenting Author: Federica Ascione Delft University of Technology

Presenting Author Biography: Federica Ascione is a mechanical engineer with expertise in modelling, design, optimization, and testing of refrigeration and power systems. She graduated from the University of Naples Federico II in 2018, then she joined the von Karman Institute for fluid-dynamics. Her research at the institute focused on the aerothermal characterization of additive manufactured heat exchangers. In 2020, she started her Ph.D. at the Propulsion and Power group at the Aerospace faculty of Delft University of Technology, where she investigated alternative solutions for the thermal management system of passenger aircraft. Currently, she works as a postdoctoral researcher in the same group, where she focuses on the thermal management of fuel cells for aircraft powertrain.

Authors:

Federica Ascione Delft University of Technology
Adam Joseph Head Delft University of Technology
Piero Colonna Delft University of Technology
Carlo Maria De Servi Delft University of Technology