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The operation of chiller systems could account for considerable electricity consumption in air‐conditioned buildings in subtropical regions. The purpose of this paper is to consider using data envelopment analysis (DEA) to facilitate management of their energy performance.

A system serving an institutional building was studied, which contains five sets of chillers, pumps and cooling towers. The building has a total floor area of about 25,000m² and comprises classrooms, lecture theatres, offices and laboratories. The scale, technical and overall efficiencies defined in DEA were calculated based on the correlation between the output variable – system coefficient of performance (COP) – and the input variables – load factor and temperatures of chilled water and condenser water. The efficiencies were further examined to explain how outside air temperatures and controllable variables affect the system performance.

The paper reveals that existing energy management gives a technical efficiency of 0.85 and fine‐tuning the temperature‐related variables could achieve an electricity saving of 14.8 per cent.

The improved COP predicted by DEA is related only to fine‐tuning of the input variables concerned. An increase of COP by other advanced controls or system upgrades should be assessed based on robust system modelling techniques. Yet the extent of COP improvements helps investigate energy management opportunities requiring no or insignificant capital investment on existing systems.

A systematic approach to performing energy management of a chiller system is proposed. The DEA helps examine which operating variable should be fine‐tuned to achieve the highest possible performance.

It is an under researched area to consider using scale and technical efficiencies in DEA to explain energy management of chiller systems and to estimate the highest achievable performance.

Today’s modern liquid propellant rocket engines have a very complicated structure. They cannot be arbitrarily downsized, ensuring efficient propellants’ mixing and combustion. Moreover, the thermodynamic cycle’s efficiency is relatively low. Utilizing detonation instead of deflagration could lead to a significant reduction of engine chamber dimensions and mass. Nowadays, laboratory research is conducted in the field of rotating detonation engine (RDE) testing worldwide. The aim of this paper is to cover the design of a flight demonstrator utilizing rocket RDE technology.

It presents the key project iterations made during the design of the gaseous oxygen and methane-propelled rocket. One of the main goals was to develop a rocket that could be fully recoverable. The recovery module uses a parachute assembly. The paper describes the rocket’s main subsystems. Moreover, vehicle visualizations are presented. Simple performance estimations are also shown.

This paper shows that the development of a small, open-structure, rocket RDE-powered vehicle is feasible.

Flight propulsion system experimentation is on-going. However, first tests were conducted with lower propellant feeding pressures than required for the first launch.

Importantly, the vehicle can be a test platform for a variety of technologies. The rocket’s possible further development, including educational use, is proposed.

Up-to-date, no information about any flying vehicles using RDE propulsion systems can be found. If successful in-flight experimentation was conducted, it would be a major milestone in the development of next-generation propulsion systems.