Assessment of Waste Heat Recovery From a Heavy-Duty Truck Engine by Means of an ORC Turbogenerator

Lang, Wolfgang; Colonna, Piero; Almbauer, Raimund

doi:10.1115/1.4023123

Cited by 43 publications

(19 citation statements)

References 34 publications

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“…In order to better illustrate how x is defined, an exemplary application of this design method is first introduced, namely the preliminary design of a mORC unit (power capacity < 20 kW) for the conversion of medium-temperature thermal sources (maximum cycle temperature < 240 C), and adopting a single-stage radial inflow turbine. This design problem, representative of applications like waste heat recovery from long-haul truck diesel engines [2], or solar power conversion in space [18,19], is particularly challenging because the choice of system operating conditions, working fluid, and components design, are mutually constrained [16]. Fig.…”

Section: Methodsmentioning

confidence: 99%

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Active subspaces for the optimal meanline design of unconventional turbomachinery

Bahamonde

Pini

Servi

et al. 2017

Applied Thermal Engineering

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h i g h l i g h t sA reduced-order model is proposed for the design of unconventional turbomachinery. The surrogate combines fluid selection, cycle configuration, and turbine geometry. The surrogate outperforms the standard model with negligible computational cost. The new response surface reveals the dominant inputs for turbine performance. The preliminary fluid dynamic design of turbomachinery operating with non-standard working fluids and unusual operating conditions and specifications can be very challenging because of the lack of know-how and guidelines. Examples are the design of turbomachinery for small-capacity organic Rankine cycle and supercritical CO 2 cycle power plants, whereby the efficiency of turbomachinery components has also a strong influence on the net conversion efficiency of the system. These machines operate with the fluid in thermodynamic states which, for part of the process, largely deviate from those obeying to the ideal gas law. This in turn implies the presence of so-called non-ideal compressible fluid dynamics effects. a r t i c l e i n f oActive subspaces, a model reduction technique, is at the basis of the methodology presented here, which is aimed at the optimal meanline design of unconventional turbomachinery. The resulting surrogate model depends on a very small set of non-physical variables, called active variables. The procedure integrates into a single constrained optimization framework the selection of the working fluid, the thermodynamic cycle calculation and the preliminary sizing of the turbomachinery component.As a demonstration of the advantages of the proposed approach, the design of a 10 kW mini organic Rankine cycle turbine with a turbine inlet temperature of 240 C is illustrated. In this case, approximately the same maximum efficiency is estimated for three dissimilar turbines operating with different working fluids and rather different thermodynamic cycles. The use of active subspaces allows the seamless evaluation of the sensitivity of results to input parameters, both those related to the machine and the working fluid. The novel design procedure is compared in terms of computational efficiency to a conventional approach based on the coupling of a genetic algorithm directly with a meanline code. Results show that the calculation based on the use of surrogate models is more than two orders of magnitude faster. The surrogate can be used to solve any design problem within the specified boundaries of the design envelope. Results are affected by uncertainty on the estimation of losses and of non-ideal compressible fluid dynamics effects, which, in turn, do not affect the applicability of the method, which will become quantitatively accurate once this information will be available. Work to this end is underway in various laboratories.

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Section: Methodsmentioning

confidence: 99%

“…In particular, R&D activities on mini ORC systems ðmORC; 3-50 kWÞ are considerably raising, because they are envisioned to play a relevant role in the decentralized energy generation scenario, and as waste heat recovery (WHR) systems for mobile engines, e.g., on board of long-haul trucks, ships, or aircraft [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Active subspaces for the optimal meanline design of unconventional turbomachinery

Bahamonde

Pini

Servi

et al. 2017

Applied Thermal Engineering

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“…High temperature heat sources such as exhaust gases from internal combustion engines require very high pressure ratios, which are achieved by a turbo-expander such as those presented in [5,6]. The relatively small enthalpy drop of organic fluids permits these pressure ratios to be achieved over a single stage, but at the expense of introducing supersonic flows within turbine.…”

Section: Introductionmentioning

confidence: 99%

The impact of component performance on the overall cycle performance of small-scale low temperature organic Rankine cycles

White

Sayma

2015

IOP Conf. Ser.: Mater. Sci. Eng.

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Experimental and numerical assessment of normal heat flux first wall qualification mock-ups under ITER relevant conditions J Du, A Bürger, G Pintsuk et al. Email: Martin.White.1@city.ac.uk Abstract. 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 to assume that the same expander must have the ability to be implemented within a number of different ORC applications. It is therefore important to design and optimise the cycle considering the component performance, most notably the expander, both at different thermodynamic conditions, and using alternative organic fluids. This paper demonstrates a novel modelling methodology that combines a previously generated turbine performance map with cycle analysis to establish at what heat source conditions optimal system performance can be achieved using an existing turbine design. The results obtained show that the same turbine can be effectively utilised within a number of different ORC applications by changing the working fluid. By selecting suitable working fluids, this turbine can be used to convert pressurised hot water at temperatures between 360K and 400K, and mass flow rates between 0.45kg/s and 2.7kg/s, into useful power with outputs between 1.5kW and 27kW. This is a significant result since it allows the same turbine to be implemented into a variety of applications, improving the economy of scale. This work has also confirmed the suitability of the candidate turbine for a range of low temperature ORC applications.

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“…For pressures under 40 bar no adjustment is necessary so that the pressure factor F p is set to unity. The area of the heat exchangers is calculated using a correlation by Hewitt et al [38]: (27) with the heat input into the cycle Q in , the total heat-transfer coefficient h t and the log mean temperature difference between the heat source and the working fluid ∆T LM . For the Up-THERM heat converter the heat input is calculated according to Equation (1) and for the ORC engine the heat input is calculated using Equation (19).…”

Section: Economic Analysis Of Cycle Componentsmentioning

confidence: 99%

Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

2016

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Abstract:The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small-to medium-scale combined heat and power (CHP) applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative) organic Rankine cycle (ORC) heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210°C to 500°C and five different working fluids (three n-alkanes and two refrigerants). A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW) of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.

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Assessment of Waste Heat Recovery From a Heavy-Duty Truck Engine by Means of an ORC Turbogenerator

Cited by 43 publications

References 34 publications

Active subspaces for the optimal meanline design of unconventional turbomachinery

Active subspaces for the optimal meanline design of unconventional turbomachinery

The impact of component performance on the overall cycle performance of small-scale low temperature organic Rankine cycles

Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

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