Search

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 CO2 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. Active 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 10kW 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.

This paper presents a feasibility study on a waste heat recovery system for heavy-duty truck engines based on organic Rankine cycle (ORC) technology. The elements of novelty of the work are: i) the proposed plant configuration, and ii) the feasibility study that encompasses the whole preliminary design workflow of the system, namely, from the thermodynamic cycle optimization and the components preliminary sizing, to dynamic modelling and the design of a PI-based control system. The conceived ORC turbogenerator employs hexamethyldisiloxane (MM) as working fluid and achieves a maximum rated mechanical power of approximately 5 kW at the design point, corresponding to a truck cruise speed and a Diesel engine power output of 85 km h-1 and 100 kW respectively. Regarding the dynamic performance, the higher response time of the ORC unit compared to that of the Diesel engine makes the adoption of an advanced control system necessary. In particular, the simulation of a PI-based control system shows that it becomes impossible to prevent the thermal decomposition of the working fluid when the engine operates continuously at high power levels. This case study demonstrates the importance for automotive ORC applications of performing the investigation of dynamic performance and control design already in the early design phase.

There is a high potential for civil applications of Unmanned Aerial Vehicles (UAV) in areas such as goods transport, telecommunication, remote monitoring and sensing, surveillance, search and rescue, and disaster management. Developments in areas such as telecommunication, control and information technology offer opportunities for long range remotely or automatically piloted missions. This requires efficient and light-weight small propulsion systems. The potential of turboprop propulsion for civil UAVs using micro turbine technology has been explored and compared with existing concepts, such as piston engine driven propellers. Different propulsion concepts have been analyzed and the application areas where advanced turboprops would be superior to other systems such as reciprocating engines and electric motors, identified. However, turboprop engines of the small power capacity required for the aircraft concepts and missions considered are not currently available with competitive performance. A conceptual design study of a micro turboprop engine has been performed by downscaling an existing reference engine. Scale effects on efficiency have been taken into account, as well as effects of technological progress. Engine cycle optimization has been carried out and the effects of turbine inlet temperature, compressor pressure ratio, engine size, and component efficiency have been investigated. An aerodynamic and flight performance model of a baseline UAV has been developed in order to predict mission performance. This model has been coupled to a turboprop model to evaluate system performance with different engine configurations for the selected mission. The outcome of the study provides information about the technological improvements in terms of cycle efficiency required to make the micro-turboprop a competitive solution. The Propulsion and Power group of Delft University of Technology will pursue these R&D goals in an attempt to contribute to the development of civil UAV technology.

Organic Rankine Cycle (ORC) power systems are receiving increased recognition for the conversion of thermal energy when the source potential and/or its temperature are comparatively low. Mini-ORC units in the power output range of 3–50 kWe are actively studied for applications involving heat recovery from automotive engines and the exploitation of solar energy. Efficient expanders are the enabling components of such systems, and all the related developments are at the early research stage. Notably, no experimental gasdynamic data are available in the open literature concerning the fluids and flow conditions of interest for mini-ORC expanders. Therefore, all the performance estimation and the fluid dynamic design methodologies adopted in the field rely on non-validated tools. In order to bridge this gap, a new experimental facility capable of continuous operation is being designed and built at Delft University of Technology, the Netherlands. The Organic Rankine Cycle Hybrid Integrated Device (ORCHID) is a research facility resembling a state-of-the-art high-temperature ORC system. It is flexible enough to treat different working fluids and operating conditions with the added benefit of two interchangeable Test Sections (TS’s). The first TS is a supersonic nozzle with optical access whose purpose is to perform gas dynamic experiments on dense organic flows in order to validate numerical codes. The second TS is a test-bench for mini-ORC expanders of any configuration up to a power output of 100 kWe. This paper presents the preliminary design of the ORCHID setup, discussing how the required operational flexibility was attained. The envisaged experiments of the two TS’s are also described.

The fluid dynamic preliminary design of unconventional turbomachinery is customary done with meanline design procedures coupled with gradient-free optimizers. This method features various drawbacks, since it might become computationally expensive, and it does not provide design insights or guidelines to the designer. This work proposes a strategy to abate this disadvantages, namely, the construction of a reduced-order model by means of active sub-spaces, and the use of the surrogate combined with a gradient-based optimizer. The case study is the design optimization of a Organic Rankine Cycle radial inflow turbine. The results show that active subspaces exist for this application, and that it is possible to construct a surrogate with an approximate error of ±1% for the total-to-static efficiency. Additionally, the optimization using the surrogate leads to accurate results and a computational cost at least four times faster. Furthermore, the results reveal that the models for unconventional turbomachinery feature multiple regions containing constrained optima. Active subspace methods thus prove to be a promising alternative for optimization of unconventional turbomachinery.

Integrated Gasification Combined Cycle (IGCC) power plants are an effective option to reduce emissions and implement carbon-dioxide sequestration. The combination of a very complex fuel-processing plant and a combined cycle power station leads to challenging problems as far as dynamic operation is concerned. Dynamic performance is extremely relevant because recent developments in the electricity market push toward an ever more flexible and varying operation of power plants. A dynamic model of the entire system and models of its sub-systems are indispensable tools in order to perform computer simulations aimed at process and control design. This paper presents the development of the lumped-parameters dynamic model of an entrained-flow gasifier, with special emphasis on the modeling approach. The model is implemented into software by means of the Modelica language and validated by comparison with one set of data related to the steady operation of the gasifier of the Buggenum power station in the Netherlands. Furthermore, in order to demonstrate the potential of the proposed modeling approach and the use of simulation for control design purposes, a complete model of an exemplary IGCC power plant, including its control system, has been developed, by re-using existing models of combined cycle plant components; the results of a load dispatch ramp simulation are presented and shortly discussed.

Solid oxide fuel cell (SOFC) stacks are at the core of complex and efficient energy conversion systems for distributed power generation. Such systems are currently in various stages of development. These power plants of the future feature complicated configurations, because the fuel cell demands for a complex balance of plant. Moreover, proposed SOFC-based systems for stationary applications are often connected to additional components and subsystems, such as a gasifier with its gas-cleaning section, a gas turbine, and a heat recovery system for thermal cogeneration or additional power production. For the simplest SOFC configurations, and more so for complex integrated systems, the dynamic operation of the power plant is challenging, especially because the fluctuating electrical load of distributed energy systems demand for reliable transient operation. Issues related to dynamic operation must be studied in the early design stage and simulation results can be used to optimize the system configuration, taking into account transient behavior. This paper presents the development and the validation of a non-linear dynamic lumped-parameters model of a SOFC stack suitable for integration into models of complex power plants. Particular emphasis is placed on the systematic approach to model development. The model is implemented using the open-source Modelica language, which allows for a high degree of flexibility and modularity, the main features of the model herein presented. The SOFC stack model will be incorporated into ThermoPower, a freely distributed library of reusable software components for the modeling of thermo-hydraulic processes and power plants.

This paper presents the second part of the work concerning the dynamic simulation of small steam cycle plants for power generation. The work is part of the preliminary study for a 600 kWe biomass fired steam power plant for which the complete open-loop, lumped parameter dynamic model of the steam cycle has been developed using the SimECS software described in Part I of this work. For these low-power plants, a dynamic simulation tool is especially useful because these systems must be designed to operate in transient mode for most of the time. The plant model presented here consists of the following components: feedwater pump, economizer, evaporator, superheater, impulse turbine, electrical generator and condenser. The primary heat source is modeled as a flue gas flow and no combustion models are incorporated yet to model the furnace. A description of the various components forming the complete steam cycle is given to illustrate the capabilities and modularity of the developed modeling technique. The model is first validated quantitatively against steady-state values obtained using a well known, reliable steady-state process modeling software. Subsequently, the dynamic validation is presented. Results can only be discussed based on the qualitative assessment of the observed trends because measurements are not available, being the plant in the preliminary design phase. The qualitative validation is based on four dynamic simulations involving three small step disturbances of different magnitude imposed on the pump rotational speed and on the flue gas mass flow and a single large ramp disturbance on the flue gas mass flow.

Work related to the dynamic simulation of the steam cycle of power plants is presented in two parts. In this paper, a dynamic modeling software for energy systems called SimECS, which is currently under development at the Delft University of Technology, is described and validated. SimECS follows a modular, hierarchical and causal paradigm, e.g., systems are formed by components which in turn are formed by modules with predefined causal interactions. A description of various available modules is presented in the first part of this work, while a description of the components forming a steam cycle is given in the second part. The equations implemented in the modules follow from physical relations and conservation laws in the lumped parameters form. Bilateral coupling in combination with the causality principle are applied to obtain a solving system of algebraic and differential equations (DAEs) characterized by a low index. The concepts and their implementation into software are validated by comparison with measured data coming from a laboratory scale steam cycle setup (evaporating section of a waste heat recovery boiler with a power scaling factor of 1:600). This setup was built and operated at the Department of Electronics and IT of the Politecnico di Milano and experimental data are made publicly available on the internet. Both steady state and dynamic experiments are used for validation and simulation results show satisfying agreement with the experiments.

The cumulative global capacity of organic Rankine cycle (ORC) power systems for the conversion of renewable and waste thermal energy is undergoing a rapid growth and is estimated to be approx. 2000 MWe considering only installations that went into operation after 1995. The potential for the conversion of the thermal power coming from liquid-dominated geothermal reservoirs, waste heat from primary engines or industrial processes, biomass combustion, and concentrated solar radiation into electricity is arguably enormous. ORC technology is possibly the most flexible in terms of capacity and temperature level and is currently often the only applicable technology for the conversion of external thermal energy sources. In addition, ORC power systems are suitable for the cogeneration of heating and/or cooling, another advantage in the framework of distributed power generation. Related research and development is therefore very lively. These considerations motivated the effort documented in this article, aimed at providing consistent information about the evolution, state, and future of this power conversion technology. First, basic theoretical elements on the thermodynamic cycle, working fluid, and design aspects are illustrated, together with an evaluation of the advantages and disadvantages in comparison to competing technologies. An overview of the long history of the development of ORC power systems follows, in order to place the more recent evolution into perspective. Then, a compendium of the many aspects of the state of the art is illustrated: the solutions currently adopted in commercial plants and the main-stream applications, including information about exemplary installations. A classification and terminology for ORC power plants are proposed. An outlook on the many research and development activities is provided, whereby information on new high-impact applications, such as automotive heat recovery is included. Possible directions of future developments are highlighted, ranging from efforts targeting volume-produced stationary and mobile mini-ORC systems with a power output of few kWe, up to large MWe base-load ORC plants.

Based on the increasing concern about human-induced global warming, it is expected that constraints on carbon emissions will be much stricter in the future. Integrated gasification combined cycle (IGCC) power plants are an option in the attempt to mitigate the effect of CO 2 emissions, because they can be fuelled or co-fuelled with biomass, but also, very importantly, because they can be equipped with pre-combustion CO 2 capture units. Moreover, the rapidly growing share of electricity produced by converting renewable energy sources demands for more flexible operation of future IGCC plants in order to compensate for inherently intermittent operation of wind and solar power plants. The CO 2 capture unit should therefore be able to follow the dynamic operation of the power plant, and, at the same time, meet environmental targets in terms of CO 2 removal. In order to investigate and improve the transient performance of such complex systems, dynamic process simulations performed with accurate physically based models are essential. This paper presents the development and validation of the dynamic model of the absorption and solvent regeneration unit as part of a pre-combustion CO 2 capture system, with focus on the absorber column model. The models are implemented into an open source software library following an object-oriented, equation-based modelling approach using the Modelica language. The models are validated by comparison against two sets of transient experimental data generated at the CO 2 capture pilot plant realized and operated at the Buggenum IGCC power station in the Netherlands. The model predictions satisfactorily reproduce the dynamic performance of the pilot plant considering the main process variables, such as pressures, flow rates and compositions. One of the results of this work is that, in case of physical absorption of CO 2 a well-tuned, equilibrium-based absorber model is able to accurately predict transient operation. The validated process models enable process and control system design aiming at improvement of transient performance of the pre-combustion capture unit.

In many industrial processes there is a simultaneous need for electric power and refrigeration at low temperatures. Examples are in the food and chemical industries. Nowadays the increase in fuel prices and the ecological implications are giving an impulse to energy technologies that better exploit the primary energy source and integrated production of utilities should be considered when designing a new production plant. The number of so-called trigeneration systems installations (electric generator and absorption refrigeration plant) is increasing. If low temperature refrigeration is needed (from 0 to −40 °C), ammonia–water absorption refrigeration plants can be coupled to internal combustion engines or turbogenerators. A thermodynamic system study of trigeneration configurations using a commercial software integrated with specifically designed modules is presented. The study analyzes and compares heat recovery from the primary mover at different temperature levels. In the last section a simplified economic assessment that takes into account disparate prices in European countries compares conventional electric energy supply from the grid and optimized trigeneration plants in one test case (10 MW electric power, 7000 h/year).

The performance map of a radial compressor operating with supercritical CO2 is numerically computed by means of three dimensional steady state Reynolds-averaged Navier–Stokes simulations. The results concern a 250 kW prototype. An in-house fluid dynamic solver is coupled with a thermodynamic library which ensures the highest accuracy of the thermophysical properties evaluation. Look-up table interpolation is used in order to reduce the computational cost, while keeping the desired level of accuracy in the fluid characterization. The compressor map is calculated considering three different rotational speeds (45 krpm, 50 krpm, and 55 krpm). For each speed-line several mass flow rates are simulated. Numerical results are compared to experimental data to prove the potential of the methodology.Copyright © 2014 by ASME

This paper presents the development of a system model for a pre-combustion CO2 capture process as part of an integrated gasification combined cycle power plant. This process entails the modelling of highly non-ideal, two-phase multi-component mixtures which are currently not supported by available Modelica media libraries or interfaces. Therefore, an interface prototype was developed and tested for the modelling and simulation of the CO2 capture process. Limitations concerning the modelling approach and improvements targeting the computational efficiency are discussed. Recommendations about the design of a library for the use of external property estimation code in Modelica conclude the treatment.

This article presents a methodology to help in the definition of the optimal design of power generation systems. The innovative element is the integration of requirements on dynamic performance into the system design procedure. Operational flexibility is an increasingly important specification of power systems for base- and part-load operation. Thus, it is crucial to discard, in an early phase of the design process, plant configurations which feature unacceptable dynamic performance. The test case is the preliminary design of an off-grid power plant serving an off-shore platform where one of the three gas turbines is combined with an organic Rankine cycle turbogenerator to increase the overall energy efficiency. The core of the procedure is a stationary model, capable of performing the on-design thermodynamic cycle calculation, and the design of the components of the system. The results of these simulations are used within the framework of a multi-objective optimization procedure to identify a number of equally optimal system configurations. A dynamic model of each of these systems is automatically parameterized, by inheriting its parameters values from the design model. Dynamic simulations allow then to discriminate among the initial set of solutions, thus providing the designs that also comply with dynamic requirements.

This paper documents a feasibility study on a waste heat recovery system for heavy-duty truck engines based on an organic Rankine cycle (ORC) turbogenerator. The study addresses many of the challenges of a mobile automotive application: The system must be simple, efficient, relatively small, lightweight, and the working fluid must satisfy the many technical, environmental, and toxicological requirements typical of the automotive sector. The choice of a siloxane as the working fluid allows for the preliminary design of an efficient radial turbine, whose shaft can be lubricated by the working fluid itself. The system's heat exchangers, though more voluminous than desirable, are within acceptable limits. The simulated ORC system would add approximately 9.6 kW at the design point, corresponding to a truck engine power output of 150 kW at 1500 rpm. Future work will be devoted to further system and components optimization by means of simulations, to the study of dynamic operation and control, and will be followed by the design and construction of a laboratory test bench for mini-ORC systems and components.

New promising applications of organic Rankine cycle (ORC) technology, e.g., concentrated solar power, automotive heat recovery and off-grid distributed electricity generation, demand for more dynamic operation of ORC systems. Accurate physically-based dynamic modeling plays an important role in the development of such systems, both during the preliminary design as an aid for configuration and equipment selection, and for control design and optimization purposes. A software library of modular reusable dynamic models of ORC components has been developed in the MODELICA language and is documented in the paper. The model of an exemplary ORC system, namely the 150 kWe Tri-O-Gen ORC turbogenerator is validated using few carefully conceived experiments. The simulations are able to reproduce steady-state and dynamic measurements of key variables, both in nominal and in off-design operating conditions. The validation of the library opens doors to control-related studies, and to the development of more challenging dynamic applications of ORC power plants.

The merit of using supercritical CO2 (scCO2) as the working fluid of a closed Brayton cycle gas turbine is now widely recognized, and the development of this technology is now actively pursued. scCO2 gas turbine power plants are an attractive option for solar, geothermal and nuclear energy conversion. Among the challenges which must be overcome in order to successfully bring the technology to the market, the efficiency of the compressor and turbine operating with the supercritical fluid should be increased as much as possible. High efficiency can be reached by means of sophisticated aerodynamic design, which, compared to other overall efficiency improvements, like cycle maximum pressure and temperature increase, or increase of recuperator effectiveness, does not require an increase in equipment cost, but only an additional effort in research and development. This paper reports a three-dimensional CFD study of a high-speed centrifugal compressor operating with CO2 in the thermodynamic region slightly above the vapor-liquid critical point. The investigated geometry is the compressor impeller tested in the Sandia scCO2 compression loop facility [1]. The fluid dynamic simulations are performed with a fully implicit parallel Reynolds-averaged Navier-Stokes code based on a finite volume formulation on arbitrary polyhedral mesh elements. The CFD code has been validated on test cases which are relevant for this study, see Ref. [2,3]. In order to account for the strongly nonlinear variation of the thermophysical properties of supercritical CO2, the CFD code is coupled with an extensive library for the computation of properties of fluids and mixtures [4]. Among the available models, the one based on reference equations of state for CO2 [5,6] has been selected, as implemented in one of the sub-libraries [7]. A specialized look-up table approach and a meshing technique suited for turbomachinery geometries are also among the novelties introduced in the developed methodology. A detailed evaluation of the CFD results highlights the challenges of numerical studies aimed at the simulation of technically relevant compressible flows occurring close to the liquid-vapor critical point. The data of the obtained flow field are used for a comparison with experiments performed at the Sandia scCO2 compression-loop facility.

N.V. Nuon (part of the Vattenfall Group) operates an IGCC in Buggenum and is developing a multi-fuel IGCC with CO2 capture and storage (Nuon Magnum) in Eemshaven, the Netherlands. In order to prepare for large-scale application of CO2 capture and storage, a CO2 capture pilot plant is constructed at the Buggenum IGCC plant and will be ready for testing in January 2010. The overall objective of the CO2 Catch-up project is to demonstrate pre-combustion CO2 capture and to generate knowledge in the form of useful data and operational experience. In parallel with the development, realisation and operation of the pilot plant, a test and R&D programme has been initiated together with Delft University of Technology, ECN and KEMA. In this paper, the technology is described in more detail and the test and R&D programme is outlined., Energy Procedia, 4, ISSN:1876-6102, 10th International Conference on Greenhouse Gas Control Technologies

There is a growing interest in organic Rankine cycle (ORC) turbogenerators because they are suitable as sustainable energy converters. ORC turbogenerators can efficiently utilize external heat sources at low to medium temperature in the small to medium power range. ORC turbines typically operate at very high pressure ratio and expand the organic working fluid in the dense-gas thermodynamic region, thus requiring computational fluid dynamics (CFD) solvers coupled with accurate thermodynamic models for their performance assessment and design. This article presents a comparative numerical study on the simulated flow field generated by a stator nozzle of an existing high-expansion ratio radial ORC turbine with toluene as working fluid. The analysis covers the influence on the simulated flow fields of the real-gas flow solvers: FLUENT, FINFLO, and ZFLOW, of two turbulence models and of two accurate thermodynamic models of the fluid. The results show that FLUENT is by far the most dissipative flow solver, resulting in large differences in all flow quantities and appreciably lower predictions of the isentropic nozzle efficiency. If the combination of the k−ω turbulence model and FINFLO solver is adopted, a shock-induced separation bubble appears in the calculated results. The bubble affects, in particular, the variation in the flow velocity and angle along the stator outlet. The accurate thermodynamic models by Lemmon and Span (2006, “Short Fundamental Equations of State for 20 Industrial Fluids,” J. Chem. Eng. Data, 51(3), pp. 785–850) and Goodwin (1989, “Toluene Thermophysical Properties From 178 to 800 K at Pressures to 1000 Bar,” J. Phys. Chem. Ref. Data, 18(4), pp. 1565–1636) lead to small differences in the flow field, especially if compared with the large deviations that would be present if the flow were simulated based on the ideal gas law. However, the older and less accurate thermodynamic model by Goodwin does differ significantly from the more accurate Lemmon–Span thermodynamic model in its prediction of the specific enthalpy difference, which leads to a considerably different value for the specific work and stator isentropic efficiency. The above differences point to a need for experimental validation of flow solvers in real-gas conditions, if CFD tools are to be applied for performance improvements of high-expansion ratio turbines operating partly in the real-gas regime.

Dynamic simulation can play a significant role in energy conversion system design, in particular for testing the effect on the system response of different equipment choices, for control system design, operator training and safety/environmental assessment. With reference to a small biomass-fired steam power plant, this paper compares two implementations of a dynamic model of the plant: the first, based on a causal approach and implemented using the Matlab/Simulink software, the second, based on an a-causal object-oriented approach, implemented in the Modelica language and simulated with the Dymola program. The results of transient simulations are compared, and the merits of the two modeling approaches are discussed.Copyright © 2007 by ASME

Dynamic modeling and simulation of steam power plants is often adopted as a tool for control design, personnel training, efficiency improvement and on-line diagnostic. The boiler is possibly the most complex component of the thermal power plant. A usual boiler configuration is the so-called Once-Through arrangement. A common problem in 2-phase systems modeling is the correct calculation of the phase boundary. This is technically interesting in such boilers: the location of the phase transition changes rapidly depending on load conditions and temperature distribution along the walls. A lumped parameters, one-dimensional evaporator model implementing a moving boundary approach is presented and first validation results are discussed. The model takes into account the influence of radiation and convection on the gas side. The flow inside the pipes is divided into 3 regions (sub-cooled, 2-phase, superheated) and the model calculates the locations of the 2-phase transitions and the average steam quality along the pipes. The system is discretized using a staggered grid for higher numerical stability and is implemented in the computer program Aspen Custom Modeler (ACM). Results include the calculation of the system response to input signals simulating a load variation and a validation by comparison with a model implemented in a commercial software for power plant simulations (MMS). Input data, parameters and geometry are taken from an existing plant operating in Uppsala, Sweden.Copyright © 2003 by ASME

An open-loop dynamic model of a small biomass fired steam power plant (Rankine Cycle) is implemented using SimECS (Simulation library for Energy Conversion Systems), a MATLAB r /Simulink r toolbox currently under development at the Delft University of Technology. The complete system is formed by the following components: feedwater pump, preheater, evaporator, superheater, impulse turbine, electrical generator and condenser. The primary heat source is modelled as a flue gas flow and no combustion is considered yet. SimECS follows the modular paradigm, e.g. the system is formed by components which in turn are formed by modules. The modules’ equations follow from conservation laws in the lumped parameters form and physical relations. Causality and bilateral coupling principles are applied to obtain a solving system of algebraic and dierential equations characterized by a low index. The toolbox is validated first by comparison with measured data coming from a laboratory-scale steam cycle (evaporating section of a waste heat recovery boiler with a power-scaling factor of 1:600). The pilot plant was built at the Dept. of Electronics and IT of the Politecnico di Milano and experiments’ recordings are made available on the internet. The complete open-loop dynamic model of the Rankine Cycle is validated qualitatively. Furthermore, steady-state results are compared with the output of an analogous model developed with a well known steady-state process modelling software.