Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Research Associate







ACE ExtensionSouth Kensington Campus






BibTex format

author = {Unamba, CK and Sapin, P and Li, X and Song, J and Wang, K and Shu, G and Tian, H and Markides, CN},
doi = {10.3390/app9153024},
journal = {Applied Sciences},
pages = {3024--3024},
title = {Operational optimisation of a non-recuperative 1-kWe organic Rankine cycle engine prototype},
url = {},
volume = {9},
year = {2019}

RIS format (EndNote, RefMan)

AB - Several heat-to-power conversion technologies are being proposed as suitable for waste-heat recovery (WHR) applications, including thermoelectric generators, hot-air (e.g., Ericsson or Stirling) engines and vapour-cycle engines such as steam or organic Rankine cycle (ORC) power systems. The latter technology has demonstrated the highest efficiencies at small and intermediate scales and low to medium heat-source temperatures and is considered a suitable option for WHR in relevant applications. However, ORC systems experience variations in performance at part-load or off-design conditions, which need to be predicted accurately by empirical or physics-based models if one is to assess accurately the techno-economic potential of such ORC-WHR solutions. This paper presents results from an experimental investigation of the part-load performance of a 1-kWe ORC engine, operated with R245fa as a working fluid, with the aim of producing high-fidelity steady-state and transient data relating to the operational performance of this system. The experimental apparatus is composed of a rotary-vane pump, brazed-plate evaporator and condenser units and a scroll expander magnetically coupled to a generator with an adjustable resistive load. An electric heater is used to provide a hot oil-stream to the evaporator, supplied at three different temperatures in the current study: 100, 120 and 140 C. The optimal operating conditions, that is, pump speed and expander load, are determined at various heat-source conditions, thus resulting in a total of 124 steady-state data points used to analyse the part-load performance of the engine. A maximum thermal efficiency of 4.2 ± 0.1% is reported for a heat-source temperature of 120 C, while a maximum net power output of 508 ± 2 W is obtained for a heat-source temperature at 140 C. For a 100- C heat source, a maximum exergy efficiency of 18.7 ± 0.3% is achieved. A detailed exergy analysis all
AU - Unamba,CK
AU - Sapin,P
AU - Li,X
AU - Song,J
AU - Wang,K
AU - Shu,G
AU - Tian,H
AU - Markides,CN
DO - 10.3390/app9153024
EP - 3024
PY - 2019///
SN - 2076-3417
SP - 3024
TI - Operational optimisation of a non-recuperative 1-kWe organic Rankine cycle engine prototype
T2 - Applied Sciences
UR -
UR -
UR -
VL - 9
ER -