Martin White

Martin White
University of Sussex

PhD, MEng

About

46
Publications
12,353
Reads
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526
Citations
Citations since 2016
41 Research Items
513 Citations
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
2016201720182019202020212022020406080100120
Introduction
I am currently a Royal Academy of Engineering Research Fellow and Senor Lecturer in Mechanical Engineering at the University of Sussex. My research focus is on the development of small-scale energy systems suitable for the power generation from low- and medium-temperature heat sources, such as solar, biomass, geothermal and waste heat. This encompasses system design and optimisation, working-fluid selection and component design and simulation, with significant focus on turbomachinery components.
Additional affiliations
September 2019 - present
City, University of London
Position
  • Lecturer
May 2018 - August 2019
City, University of London
Position
  • Research Associate
Description
  • I worked on a project which aims at improving our understanding of loss mechanisms with ORC expanders. In particular, the focus of this work was on radial turbines.
May 2017 - May 2018
City, University of London
Position
  • PostDoc Position
Education
April 2013 - September 2015
City, University of London
Field of study
  • Mechanical Engineering
September 2007 - July 2011
University of Southampton
Field of study
  • Mechanical Engineering (Sustainable Energy Systems)

Publications

Publications (46)
Article
Full-text available
For small-scale organic Rankine cycles (ORCs) to be a competitive technology, it is rea- sonable to assume that the same turbine design will be implemented into a range of dif- ferent applications. It is therefore critical to be able to predict turbine off-design performance over a range of different operating conditions while utilizing different w...
Article
Full-text available
Organic Rankine cycles (ORC) are becoming a major research area within the field of sustainable energy systems. However, a major challenge facing the widespread implementation of small and mini-scale ORC systems is the economy-of-scale. To overcome this challenge requires single components that can be manufactured in large volumes and then implemen...
Article
Full-text available
A mixed-integer non-linear programming optimisation framework is formulated and developed that combines a molecular-based, group-contribution equation of state, SAFT-γ Mie, with a thermodynamic description of an organic Rankine cycle (ORC) power system. In this framework, a set of working fluids is described by its constituent functional groups (e....
Article
Full-text available
The wider adoption of organic Rankine cycle (ORC) technology for power generation or cogeneration from renewable or recovered waste-heat in many applications can be facilitated by improved thermodynamic performance, but also reduced investment costs. In this context, it is suggested that the further development of ORC power systems should be guided...
Article
Full-text available
The design of optimal organic Rankine cycle (ORC) systems requires the simultaneous identification of the optimal cycle architecture, operating conditions and working fluid, whilst accounting for the effect of these parameters on expander performance. In this paper, a novel method for predicting the design-point efficiency of a radial turbine is de...
Conference Paper
Full-text available
Within this study, the blade shape of a large-scale axial turbine operating with sCO2 blended with dopants is optimised using an integrated aerodynamic-structural 3D numerical model, whereby the optimisation aims at maximising the aerodynamic efficiency whilst meeting a set of stress constraints to ensure safe operation. Specifically, three candida...
Article
Full-text available
Within this study, the blade shape of a large-scale axial turbine operating with sCO2 blended with dopants is optimised using an integrated aerodynamic-structural numerical model to maximise the aerodynamic efficiency whilst meeting stress constraints. Three candidate mixtures are considered, namely CO2 blended with titaniumtetrachloride (TiCl4), h...
Article
Full-text available
Loss models are used to evaluate the aerodynamic performance of axial turbines at the preliminary design stage. The commonly used loss models were derived for air and steam turbines and have not been sufficiently investigated for turbines working with non-conventional working fluids, relevant to new power systems, such as organic fluids and supercr...
Article
Full-text available
The successful and economic conversion of waste heat into electricity requires new, innovative, power cycles to be developed. The proposed wet-to-dry cycle, in which the working fluid transitions across the saturation dome during expansion, has been shown to offer significant thermodynamic benefits. However , the feasibility of achieving wet-to-dry...
Conference Paper
Full-text available
Two-phase expansion has previously been considered as a means to improve the performance of ORC systems for waste-heat recovery applications. However, ORC turbomachinery has almost exclusively been designed for operation with either superheated or saturated vapour, whilst during experimental testing turbine operation close the saturation region is...
Conference Paper
Full-text available
A detailed loss assessment of an axial turbine stage operating with a supercritical carbon dioxide (sCO2) based mixture, namely titanium tetrachloride (CO2-TiCl4 85-15%), is presented. To assess aerodynamic losses, computational fluid dynamics (CFD) simulations are conducted using a geometry generated using mean-line design equations which is part...
Article
Full-text available
Supercritical CO2 (sCO2) power cycles have gained prominence for their expected excellent performance and compactness. Among their benefits, they may potentially reduce the cost of Concentrated Solar Power (CSP) plants. Because the critical temperature of CO2 is close to ambient temperatures in areas with good solar irradiation, dry cooling may pen...
Conference Paper
Full-text available
Doping CO2 with an additional fluid to produce a CO2-based mixture is predicted to enhance the performance of the super critical CO2 power cycle and lower its cost when adapted to Concentrated Solar Power plants. A consistent fluid mixture modelling process is necessary to reliably design and predict the performance of turbines operating with CO2-b...
Article
Full-text available
Previous investigations suggest the power output from waste-heat recovery organic Rankine cycle (ORC) systems could be enhanced by up to 30% by operating with two-phase expansion, which could reduce cost and aid in the more widespread deployment of ORC technology. However, there are limited expander technologies suitable for such operation. The aim...
Chapter
The aim of the work presented in this paper is to explore the validity and possible extent to which non-ideal compressible-fluid dynamic (NICFD) effects may have a role in the expansion of a two-phase mixture of the siloxane MM by expanding the concept of the fundamental derivative to two-phase flows. For the assumption of a homogeneous two-phase m...
Article
Full-text available
Thermal-power cycles operating with supercritical carbon dioxide (sCO2) could have a significant role in future power generation systems with applications including fossil fuel, nuclear power, concentrated-solar power, and waste-heat recovery. The use of sCO2 as a working fluid offers potential benefits including high thermal efficiencies using hea...
Article
Full-text available
The design of single-stage organic Rankine cycle (ORC) systems can be challenging owing to large volumetric expansion ratios and sub-atmospheric condensation pressures. Cascaded systems could lead to more efficient expansion processes, higher condensation pressures, whilst introducing the possibility of two-phase expansion to enhance performance. T...
Article
Compared to single-stage organic Rankine cycle (ORC) systems, cascaded ORC systems, in which a high-temperature topping cycle and low-temperature bottoming cycle are coupled together, could have advantages in terms of removing the potential for sub-atmospheric condensation conditions and improving expander performance as the expansion process is ef...
Conference Paper
Full-text available
The aim of this paper is to define general guidelines for fluid and cycle selection for small-scale Rankine cycle power systems based on heat-source temperature, heat-source temperature drop and heat sink availability. This is developed through optimisation studies for subcritical and supercritical cycles, which includes a model to estimate the ach...
Article
Full-text available
Supercritical carbon dioxide (sCO 2 ) power cycles are promising candidates for concentrated-solar power and waste-heat recovery applications, having advantages of compact turbomachinery and high cycle efficiencies at heat-source temperature in the range of 400 to 800 ∘ C. However, for distributed-scale systems (0.1–1.0 MW) the choice of turbomachi...
Chapter
This main objective of this paper is to present recent developments and future challenges in two distributed power generation technologies that have the potential to play an important role in the future low carbon power generation. The first is parabolic solar dish systems powering a micro gas turbine by focusing solar energy to a focal area to hea...
Article
Full-text available
The integration of thermal-energy storage (TES) within waste-heat recovery power generation systems has the potential to improve energy-efficiency in many industrial processes with variable and/or intermittent waste-heat streams. The first objective of this paper is to present a novel model of these systems that can be used at an early design stage...
Conference Paper
Full-text available
Compared to single-stage ORC systems, cascaded ORC systems could have benefits for relatively high-temperature waste-heat recovery applications, which include the potential for higher expander isentropic efficiencies owing to lower expansion ratios, the removal of sub-atmospheric condensation pressures and the possibility to utilise two-phase expan...
Article
Full-text available
Compared to single-stage organic Rankine cycle (ORC) systems, cascaded ORC systems, in which a high-temperature topping cycle and low-temperature bottoming cycle are coupled together, could have advantages in terms of removing the potential for sub-atmospheric condensation conditions and improving expander performance as the expansion process is ef...
Conference Paper
Full-text available
For waste-heat recovery applications, operating an organic Rankine cycle (ORC) with two-phase expansion has been shown to increase the utilisation of the waste-heat stream, leading to a higher power output compared to a conventional ORC with single-phase expansion. However, unlike the conventional ORC, working-fluid selection for an ORC operating w...
Conference Paper
Full-text available
The selection of an optimal working fluid and the design of the system components for a small-scale (<100 kW) high-temperature (250-400 °C) organic Rankine cycle (ORC) can be challenging owing to the possibility of sub-atmospheric condensation pressures and high expander volume-ratios. The latter means that volumetric expanders are not suitable, wh...
Conference Paper
Despite significant research activities into organic Rankine cycles for the conversion of low-temperature heat into power, there remain uncertainties with regards to non-ideal gas effects and their role in turbine performance. Moreover, existing performance models and numerical solvers have yet to be validated for turbines operating with organic fl...
Article
Full-text available
The aim of this paper is to conduct a generalised assessment of both optimal working fluids and radial turbine designs for small-scale organic Rankine cycle (ORC) systems across a range of heat-source temperatures. The former has been achieved by coupling a thermodynamic model of subcritical, non-recperated cycles with the Peng–Robinson equation of...
Conference Paper
Full-text available
The aim of this paper is to conduct a preliminary comparison of different turbine architectures for a small-scale 100 kW supercritical CO2 Rankine cycle. The turbine is required to expand supercritical CO2 from 650 °C and 170 bar, down to 50 bar. For such an application, it is not immediately clear which turbine architecture is the most suitable de...
Article
Full-text available
In this paper, the effect of working-fluid replacement within an organic Rankine cycle (ORC) turbine is investigated by evaluating the performance of two supersonic stators operating with different working fluids. After designing the two stators, intended for operation with R245fa and Toluene with stator exit absolute Mach numbers of 1.4 and 1.7, r...
Article
Full-text available
The organic Rankine cycle (ORC) is a promising technology for the conversion of waste heat from industrial processes as well as heat from renewable sources. Many efforts have been channeled towards maximizing the thermodynamic potential of ORC systems through the selection of working fluids and the optimal choice of operating parameters with the ai...
Article
Full-text available
The successful commercialisation of organic Rankine cycle (ORC) systems across a range of power outputs and heat-source temperatures demands step-changes in both improved thermodynamic performance and reduced investment costs. The former can be achieved through high-performance components and optimised system architectures operating with novel work...
Conference Paper
Full-text available
The combination of computer-aided molecular design (CAMD) with an organic Rankine cycle (ORC) power-system model presents a powerful methodology that facilitates an integrated approach to simultaneous working-fluid design and power-system thermodynamic or thermoeconomic optimisation. Existing CAMD-ORC models have been focussed on simple subcritical...
Conference Paper
Full-text available
Improvements in the thermal and economic performance of organic Rankine cycle (ORC) systems are required before the technology can be successfully implemented across a range of applications. The integration of computer-aided molecular design (CAMD) with a process model of the ORC facilitates the combined optimisation of the working-fluid and the po...
Article
Full-text available
With a growing global demand for cooling and more restrictive legislation coming into force concerning the selection of refrigerants, the refrigeration industry is looking for new alternatives. Nareshkumar Handagama, Martin White and Christos Markides discuss the role that carbon dioxide could play.
Conference Paper
Full-text available
In this paper, we develop a mixed-integer non-linear programming optimisation framework that combines working-fluid thermodynamic property predictions from a group-contribution equation of state, SAFT-𝛾 Mie, with a thermodynamic description of an organic Rankine cycle. In this model, a number of working-fluids are described by their constituent fun...
Article
Full-text available
A significant improvement in the economy-of-scale of small-scale organic Rankine cycle (ORC) systems can arise from the appropriate design of components that can be manufactured in large volumes and implemented flexibly into a wide range of systems and potential applications. This, in turn, requires accurate predictions of component performance tha...
Conference Paper
Full-text available
A significant improvement in the economy-of-scale of small-scale organic Rankine cycle (ORC) systems can arise from the appropriate design of components that can be manufactured in large volumes and implemented flexibly into a wide range of systems and potential applications. This, in turn, requires accurate predictions of component performance tha...
Conference Paper
Full-text available
Tel. +44 (0)20 759 41601 Web page: www.imperial.ac.uk/clean-energy-processes Highlights: An ORC expander test rig for WHR applications that utilises a catalytic heater as the heat source is discussed and preliminary results for a 1 kW scroll expander operating with R245fa are presented. Despite the low ORC efficiency of 2.4%, these preliminary resu...
Conference Paper
For small and micro scale (< 50 kWe) organic Rankine cycle (ORC) systems to be commercially viable, systems are required that can operate efficiently over a range of operating conditions. This will lead to the high volume, low cost production that is critical to improve the current economy of scale, and reduce system costs. This requirement will in...
Conference Paper
Rotor-dynamics of Micro Gas Turbines (MGTs) under 30 kW have been a critical issue for the successful development of reliable engines during the last decades. Especially, no consensus has been reached on a reliable MGT arrangement under 10 kW with rotational speeds above 100,000 rpm, making the understanding of the rotor-dynamics of these high spee...
Thesis
Full-text available
Over recent years, with growing concern over climate change, the need for energy which is sustainable, economical and in line with legalisation has led to a substantial surge of interest in organic Rankine cycles (ORC). With the ability to convert low temperature heat sources into power, ORC technology is at the forefront of many sustainable techno...
Conference Paper
Full-text available
Low temperature organic Rankine cycles offer a promising technology for the generation of power from low temperature heat sources. Small-scale systems (∼10kW) are of significant interest, however there is a current lack of commercially viable expanders. For a potential expander to be economically viable for small-scale applications it is reasonable...
Conference Paper
This paper presents a complete radial turbine design methodology intended for the design of a small scale organic Rankine cycle (ORC) turbo expander. The design methodology is comprised of 1D meanline design, coupled with REFPROP for real fluid properties, and 3D geometrical construction of the turbine rotor, stator and volute. A novel method to pr...
Article
Full-text available
Small-scale (10 kWe) organic Rankine cycles for low temperature applications such as heat recovery and solar power present a significant development opportunity but limited prototypes have been developed. This paper aims to address this by describing a system modelling tool which is used to select a working fluid, optimise cycle conditions, and pre...

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Projects

Projects (5)
Project
SCOTWOHR is an UK EPSRC-funded research project investigating supercritical carbon dioxide (sCO2) power cycles for industrial waste-heat recovery. It brings together leading academic experts from the two academic institutions (City, University of London and Brunel University London) and four industrial partners. Currently, there are a large number of energy intensive industries that have waste heat at temperatures and flow rates that are unsuitable for existing commercial power generation systems. Supercritical CO2 technology is an extremely promising candidate f, but the technology has not been widely commercialised due to significant technical challenges that need to be overcome. The SCOTWOHR consortium aims to conduct original research to improve the fundamental understanding of the performance sCO2 cycles and the design aspects of the key components, namely compressors, expanders and heat exchangers.
Project
This workshop is being coorganised by Metapower and members of the Thermo-Fluids Reserach Centre at City, University of London currenting investigating ORC systems for waste-heat recovery. This is a course for industry engineers and professionals, academic and researcher scholars and that provides a concise introduction to Organic Rankine Cycle (ORC) waste heat recovery technology, its principles, applications and state-of-the-art. Sign-up here: https://www.city.ac.uk/events/2020/april/organic-rankine-cycle-technology-workshop
Project
This five-year Research Fellowship awarded by the Royal Academy of Engineering will be used to explore improvements in current waste-heat recovery technologies through two-phase expansion. Waste-heat recovery power systems have an important role in improving the energy efficiency of many processes. The aim of my fellowship will be to investigate, through a combination of numerical and experimental studies, the development of new expander technologies that can successfully expand a liquid-vapour mixture, leading to improvements in the performance waste-heat recovery systems based on the organic Rankine cycle.