References of "Lemort, Vincent"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailExperimental assessment of the fluid charge distribution in an organic Rankine cycle (ORC) power system
Dickes, Rémi ULiege; Dumont, Olivier ULiege; Lemort, Vincent ULiege

in Applied Thermal Engineering (2020), 179

This paper reports on experiments aiming to understand and to characterize how the working fluid spreads in an organic Rankine cycle (ORC) power system. To this end, a 2-kWe ORC test rig is constructed ... [more ▼]

This paper reports on experiments aiming to understand and to characterize how the working fluid spreads in an organic Rankine cycle (ORC) power system. To this end, a 2-kWe ORC test rig is constructed and tested over a wide range of conditions. Besides standard thermo-hydraulic sensors, the fluid charge distribution is measured on-line by bending load cells and infrared imaging techniques. Following a complete experimental campaign (which includes more than 330 steady-state points and fully characterizes the ORC off-design behaviour), a dual data reconciliation method is applied to the raw measurements to obtain a reference dataset. The results are then analysed to assess the charge distribution mechanisms occurring in the ORC and how it is correlated with the system performance. Among other aspects, this paper demonstrates (i) how the charge inventory is highly correlated to the temperature profiles in the heat exchangers, (ii) how the evaporator dictates the operating conditions of the low-pressure components, and (iii) how the system charge and the liquid receiver size can be selected to maximize the ORC overall performance. [less ▲]

Detailed reference viewed: 41 (5 ULiège)
Full Text
Peer Reviewed
See detailMulti-objective design of single room ventilation units with heat and water recovery
Parthoens, Antoine ULiege; Prieels, Luc; Embrechts, Jean-Jacques ULiege et al

in International Journal of Ventilation (2020)

The present paper describes the design improvement of a single-room ventilation unit. This ventilation system presents many advantages, how- ever, several drawbacks exist. The first one is the acoustic ... [more ▼]

The present paper describes the design improvement of a single-room ventilation unit. This ventilation system presents many advantages, how- ever, several drawbacks exist. The first one is the acoustic disturbance. As the facilities are directly installed within the rooms, the fans’ noise may create discomfort. Furthermore, in the cold or temperate climates, condensation or frost may appear. A dedicated management should then be implemented. Finally, as the system is not centralized, commu- nication between the different units is required to ensure the global sys- tem efficiency. A team of several industrial partners and research institutes tackles the above-mentioned issues in the frame of the “Silenthalpic” project. The project is split in three major tasks. To cor- rectly reduce the sound emission level (i), a spectral analysis of the noise emitted by an existing unit was undertaken, revealing that fre- quencies under 1kHz are mainly responsible for the noise disturbance. From this analysis, active and passive solutions for noise reduction are envisaged, showing encouraging trends. The next research aspect is the exchanger of the ventilation unit (ii). The constituting material is a new porous membrane allowing the humidity transfer (vapor or liquid). This specific exchanger is numerically modelled to predict its performances. The last considered problematic is the optimization of the ventilation and control strategies for the specific case of decentralized units (iii), taking advantage of sensors and recent communication technologies like IOT (Internet Of Things) to establish communication between decentralized units and ensure their consistent control. The association of the three aspects presented here should then lead to versatile and efficient ventilation systems. [less ▲]

Detailed reference viewed: 35 (8 ULiège)
Full Text
Peer Reviewed
See detailDetailed Experimental and Model-Based Analysis of a Swash-Plate Piston Expander for ORC Application
Oudkerk, Jean-François; Lemort, Vincent ULiege

in Frontiers in Energy Research (2020), 8

A 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 ... [more ▼]

A 195 cm³ swash-plate piston expander was tested in an ORC using R245fa as working fluid. Rotational speeds ranging from 1000 RPM to 4000 RPM and pressure ratios from 7 to 12 were imposed. In total, 65 steady state points were measured. With these measurements, performance maps were generated to point out the influence of rotational speed and levels of pressure on mechanical power and isentropic efficiency. These maps have highlighted the existence of an optimal rotational speed of around 3000 RPM maximizing the mechanical power, while the speed that maximizes the isentropic efficiency lies between 2000 and 2500 RPM. The maximal mechanical power and isentropic efficiency were 2.8 kW and 53%, respectively. Then the measurements were used to analyze the losses. This analysis has shown that, under the expansion and compression limit, the theoretical isentropic efficiency has values comprised between 90% and 70% for pressure ratios of 7 to 12. The filling factor affects the isentropic efficiency for low rotational speeds and low pressure ratios. Indeed, indicated isentropic efficiency is around 60% for 1000 RPM and around 75% for 4000 RPM. These values stay quite constant with the pressure ratio. Finally, a mechanical efficiency comprised between 40% and 90% was observed, which lowers the isentropic efficiency to values comprised between 30% and 53%. Finally, a model based on energy and mass conservation inside a cylinder volume was successfully calibrated and was able to predict mass flow rate, mechanical power and exhaust temperature with good agreement. This model has enabled disaggregation of the influence of pressure drops and leakages on the filling factor, then on the isentropic efficiency. This analysis has shown that pressure drops mainly affect the compactness of the expander, and not so much the isentropic efficiency (except for low rotational speeds where pressure drops can lower the isentropic efficiency by 14%). In contrary, leakages have a strong impact. The importance of the different sources of losses varies with the speed. For the optimal speed of 2500 RPM, under-expansion and compression have the strongest impact, followed by mechanical losses, leakages and pressure drops, respectively. [less ▲]

Detailed reference viewed: 49 (9 ULiège)
Full Text
See detailModelling of a thermally integrated Carnot battery using a reversible heat pump/organic Rankine cycle
Dumont, Olivier ULiege; reyes, andres; Lemort, Vincent ULiege

Scientific conference (2020)

Detailed reference viewed: 18 (1 ULiège)
Full Text
Peer Reviewed
See detailCarnot battery technology: a state-of-the-art review
Dumont, Olivier ULiege; Frate, Guido Francesco; Pillai, Aditya et al

in Journal of Energy Storage (2020), 32(101756),

The growth of renewable energy requires flexible, low-cost and efficient electrical storage to balance the mismatch between energy supply and demand. The Carnot battery buffers electrical energy by ... [more ▼]

The growth of renewable energy requires flexible, low-cost and efficient electrical storage to balance the mismatch between energy supply and demand. The Carnot battery buffers electrical energy by storing thermal energy (charging cycle mode) from a resistive heater or a heat pump system when the electricity production is higher than the demand. When electricity demand is higher than the production, the Carnot battery generates power from the stored thermal energy (power cycle mode). This paper is a review of this emerging and innovative technology, including a market analysis. First, the different possible technologies and configurations of Carnot batteries are described. This includes charging cycles, power cycles and thermal energy storage systems. Furthermore, a state-of-the-art of the existing prototypes in the world is given. The performance indicators for this technology are unclear, and this paper tries to define objective performance indicators. Finally, all the described technologies are compared, and conclusions are drawn to help engineers select the optimal technology for a given case. [less ▲]

Detailed reference viewed: 27 (2 ULiège)
Full Text
Peer Reviewed
See detailExperimentally-validated models for the off-design simulation of a medium-size solar organic Rankine cycle unit
Petrollese, Mario; Dickes, Rémi ULiege; Lemort, Vincent ULiege

in Energy Conversion and Management (2020), 224(113307),

Organic Rankine Cycle is an efficient and reliable technology for the thermal-to-electricity conversion of low- grade heat sources but the variability in boundary conditions often forces these systems to ... [more ▼]

Organic Rankine Cycle is an efficient and reliable technology for the thermal-to-electricity conversion of low- grade heat sources but the variability in boundary conditions often forces these systems to operate at off- design conditions. The development of reliable models for the performance prediction of organic Rankine cycle power systems under off-design conditions is therefore crucial for system-level integration and control implementation. In this paper, a mathematical model for the evaluation of the expected performance of organic Rankine cycle power units in a large range of operating conditions based on experimental data collected in a medium-size solar organic Rankine cycle power plant is presented. Two different empirical approaches for the performance prediction of heat exchangers and machines, namely, constant-efficiency and correlated-based approaches, are proposed and compared. In addition, empirical correlations based on experimental data are proposed for the preliminary assessment of the energy demanded during the start-up phase and the corre sponding duration. Results demonstrate that a good achievement in terms of accuracy of the model and reli-ability of the simulation performance can be obtained by using a constant-efficiency approach, with average errors lower than 5% and 2.5 K for the expected net power and outlet oil temperature respectively. The use of polynomial correlations leads to a more accurate estimation of the performance parameters used for evaporator and the turbine (in particular the evaporator heat effectiveness and the isentropic and electromechanical effi-ciency for the turbine), which strongly affect the main output variables of the model and, at the same time, are remarkably influenced by the operating conditions. A reduction in the average error in the prediction of the net power and outlet temperature of the heat transfer fluid to about 4% and 1.5 K respectively is therefore achieved by this approach. Average errors of 18.5% and 12.5% are achieved for the start-up time and the corresponding energy absorbed, respectively. Although the results obtained in terms of accuracy could be improved, these correlations can give an initial indication about the duration and energy required during this phase. [less ▲]

Detailed reference viewed: 27 (2 ULiège)
Full Text
Peer Reviewed
See detailGeometry Definition and Performance Assessment of Tesla Turbines for ORC
Talluri, Lorenzo; Dumont, Olivier ULiege; Manfrida, Giampaolo et al

in Energy (2020)

The Tesla turbine - also known as friction, viscous or bladeless turbine - is a peculiar expander, which generates power through viscous entrainment. In the last years, it has gained a renewed appeal due ... [more ▼]

The Tesla turbine - also known as friction, viscous or bladeless turbine - is a peculiar expander, which generates power through viscous entrainment. In the last years, it has gained a renewed appeal due to the rising of distributed power generation applications. Indeed, this expander is not suitable to large size power generation, but it could become a breakthrough technology in the low power ranges, due to its characteristics of low cost and reliability.The current study presents a design approach to the Tesla turbine, applied to organic working fluids (R1233zd(E), R245fa, R1234yf, n-Hexane). Three fundamental geometric parameters are identified (rotor channel width/inlet diameter ratio, rotor outlet/inlet diameter ratio, throat width ratio) and their effects on the performance are analyzed. The geometry of the turbine has been defined and the assessment of the performance potential is run, applying a 2D code for the viscous flow solution, considering real compressible fluid properties.For all the investigated working fluids, an efficiency higher than 60% has been achieved, with the defined geometry, under suitable thermo fluid-dynamic conditions. [less ▲]

Detailed reference viewed: 28 (2 ULiège)
Full Text
Peer Reviewed
See detailSizing and Operation of an Isolated Microgrid with Building Thermal Dynamics and Cold Storage
Dakir, Selmane ULiege; Boukas, Ioannis ULiege; Lemort, Vincent ULiege et al

in IEEE Transactions on Industry Applications (2020)

An effective way to properly integrate renewable energy sources and to exploit the available flexibility in a decentralized manner is through the development of microgrids. It has been demonstrated that ... [more ▼]

An effective way to properly integrate renewable energy sources and to exploit the available flexibility in a decentralized manner is through the development of microgrids. It has been demonstrated that the use of an ice-based cold storage system can reduce the total cost of energy in the context of an isolated microgrid where the main goal is the procurement of the electrical and cooling demand. In this paper, we consider as an additional source of flexibility the potential from the thermal inertia of the buildings. To this end, a controller that takes into account as an optimization variable the interior temperature of the buildings is developed. Additional to the flexibility, a better utilization of the available renewable resources can thus be acquired. A simulator is implemented in which every microgrid component is modeled in detail in order to simulate the operations of the entire system. The results show that the combination of the cold storage system with the dynamic control of the indoors temperature can reduce the operating costs of the microgrid by 68%. [less ▲]

Detailed reference viewed: 37 (8 ULiège)
Full Text
Peer Reviewed
See detailModélisation et Simulation d’un Cycle de Rankine Organique pour de la récupération de chaleur perdue sur le liquide de refroidissement d’un moteur de camion
Leclercq, Nicolas ULiege; Lemort, Vincent ULiege

in Actes du congrès de la SFT (2020)

In this study, a dynamic model of an Organic Rankine Cycle for truck coolant recovery is presented. The system is simulated on a real road cycle (Lyon-Chambéry-Goncelin, France) with both Novec649 and ... [more ▼]

In this study, a dynamic model of an Organic Rankine Cycle for truck coolant recovery is presented. The system is simulated on a real road cycle (Lyon-Chambéry-Goncelin, France) with both Novec649 and R1233zd as working fluids. The working conditions being transient, a control is required for internal cycle variables such as the superheating and the subcooling for the system to operate properly. The expansion is done with a turbine and allows recovering average net powers of 1332 W for Novec649 and 1641 W for R1233zd out of 50 kW boiler power without recuperator. [less ▲]

Detailed reference viewed: 36 (8 ULiège)
Full Text
Peer Reviewed
See detailExperimental investigation of an Organic Rankine Cycle Tesla turbine working with R1233zd(E)
Talluri, Lorenzo; Dumont, Olivier ULiege; Manfrida, Giampaolo et al

in Applied Thermal Engineering (2020), 174

The increasing interest in micro power generation is pushing the research world to find new solutions for increasing the efficiency of micro Organic Rankine Cycles. One of their main issues is the ... [more ▼]

The increasing interest in micro power generation is pushing the research world to find new solutions for increasing the efficiency of micro Organic Rankine Cycles. One of their main issues is the efficiency and the reliability of the expander. The Tesla turbine is an old/new expander, which has found a renewed interest in the last years because of the increasing appeal towards distributed micro generation, where this expander becomes competitive. This peculiar technology seems adapted to micro generation in Organic Rankine Cycle thanks to its main characteristic, which is its simple structure that allows for high reliability and cheapness. In recent years, this expander has been analytically and numerically assessed when working with organic fluids. In this study, the experimental investigation of a Tesla turbine working with R1233zd(E) is presented. One of the main achievements was the assessment of the blockage effect of disks edges when the pressure drop through the machine is relevant as in case of Organic Rankine Cycles (e.g. higher than 3–4 bars), resulting into a relatively large amount of flow deviation through the clearances between the rotor disks package and the case, which implies a throttling effect thus resulting into a relevant performance loss. This effect was accounted by a model that well fitted the experimental data. The achieved results confirmed the validity and the large applications potential of this emerging technology, especially in the fields of micro power generation, low inlet temperature and low expansion ratios. A maximum net power output of 371 W was obtained, proving the feasibility of utilizing Tesla turbines in Organic Rankine Cycle applications. A maximum shaft efficiency of 9.62% and a maximum adiabatic efficiency of 30% were achieved. The results and the developed model of disks edge losses effects represent an important step ahead, in physical depiction of the phenomenology, over the currently available literature, fundamental for the improvement of the design procedure of Tesla turbines for Organic Rankine Cycles. [less ▲]

Detailed reference viewed: 52 (3 ULiège)
Full Text
Peer Reviewed
See detailModelling of an exhaust air heat pump used for heating and domestic hot water production
Ransy, Frédéric ULiege; Gendebien, Samuel ULiege; Lemort, Vincent ULiege

in Proceedings of the 10th International Conference on System Simulation in Buildings (2020)

Exhaust heat pump is a promising solution to heat and ventilate a building with a high energy efficiency, and a competitive investment cost. The authors presented in 2015 laboratory test results about an ... [more ▼]

Exhaust heat pump is a promising solution to heat and ventilate a building with a high energy efficiency, and a competitive investment cost. The authors presented in 2015 laboratory test results about an exhaust heat pump and showed a COP of 4.4 for the conditions A22W35. A simple annual extrapolation of the results showed a similar primary energy consumption than the conventional balanced ventilation system combined with an outside air heat pump. However, the authors presented in 2018 the performance of the same machine integrated in a demonstration building in Belgium. Due to the ultra-low heating capacity (1500 W), the measured overall COP of the system was 2.18. In order to increase the heating capacity of the system, this paper presents a semi-empirical model of the heat pump to study the impact of the design of the different elements of the machine on the performance. [less ▲]

Detailed reference viewed: 79 (5 ULiège)
Full Text
Peer Reviewed
See detailPDSim: A general quasi-steady modeling approach for positive displacement compressors and expanders
Bell, Ian ULiege; Ziviani, Davide; Lemort, Vincent ULiege et al

in International Journal of Refrigeration (2020), 110

Detailed reference viewed: 66 (8 ULiège)
Full Text
Peer Reviewed
See detailPDSim: Demonstrating the capabilities of an open-source simulation framework for positive displacement compressors and expanders
Ziviani, Davide; Bell, Ian; Zhang, Xinye et al

in International Journal of Refrigeration (2020), 110

Detailed reference viewed: 58 (3 ULiège)
Full Text
Peer Reviewed
See detailMulti-objective design of single room ventilation units with heat and water recovery
Parthoens, Antoine ULiege; Prieels, Luc ULiege; Embrechts, Jean-Jacques ULiege et al

in From energy crisis to sustainable indoor climate – 40 years of AIVC (2019, October)

The present paper describes the design improvement of a single-room ventilation unit. This ventilation system presents many advantages, however, several drawbacks exist. The first one is the acoustic ... [more ▼]

The present paper describes the design improvement of a single-room ventilation unit. This ventilation system presents many advantages, however, several drawbacks exist. The first one is the acoustic disturbance. As the facilities are directly installed within the rooms, the fans’ noise may create discomfort. Furthermore, in the cold or temperate climates, condensation or frost may appear. A dedicated management should then be implemented. Finally, as the system is not centralized, communication between the different units is required to ensure the global system efficiency. A team of several industrial partners and research institutes tackles the above-mentioned issues in the frame of the “Silenthalpic” project. The project is split in three major tasks. To correctly reduce the sound emission level (i), a spectral analysis of the noise emitted by an existing unit was undertaken, revealing that frequencies under 1 kHz are mainly responsible for the noise disturbance. From this analysis, active and passive solutions for noise reduction are envisaged, showing encouraging trends. The next research aspect is the exchanger of the ventilation unit (ii). The constituting material is a new porous membrane allowing the humidity transfer (vapor or liquid). This specific exchanger is numerically modelled to predict its performances. The last considered problematic is the optimization of the ventilation and control strategies for the specific case of decentralized units (iii), taking advantage of sensors and recent communication technologies like IOT (Internet Of Things) to establish communication between decentralized units and ensure their consistent control. The association of the three aspects presented here should then lead to versatile and efficient ventilation systems. [less ▲]

Detailed reference viewed: 76 (8 ULiège)
Full Text
Peer Reviewed
See detailAssessment of Rankine Waste Heat Recovery Potential on Heavy Duty Trucks Using Direct Condensation
Galuppo, Francesco; Reiche, Thomas; Lemort, Vincent ULiege et al

in Proceedings of the 5th International Seminar on ORC Power Systems (2019, September)

Upcoming regulations on CO2 emissions for heavy duty trucks and increasing fuel prices lead the truck manufacturers to adopt new solutions to reduce fuel consumption. The Organic Rankine cycle (ORC) is a ... [more ▼]

Upcoming regulations on CO2 emissions for heavy duty trucks and increasing fuel prices lead the truck manufacturers to adopt new solutions to reduce fuel consumption. The Organic Rankine cycle (ORC) is a promising technology that can contribute to achieve such a goal. Rankine cycle waste heat recovery on heavy duty trucks has been studied over the past decade by focusing on fluid selection, modeling, control and components development. Cost, integration and up-time are also considered important aspects for a future series production. The objective of this study is to evaluate the performance of a Rankine system by simulating road cycles on a complete truck simulation environment (Exhaust after treatment system, as well as cooling system and the energy management of the mild-hybrid driveline are modeled). The Rankine system uses exhaust gas flow as heat source, an air cooled condenser and a volumetric expansion machine. Two working fluids are selected for this study; ethanol and cyclopentane. The dynamic equations used for Rankine component modeling are provided and a particular attention is dedicated to the condenser and fan models. In order to ensure complete condensation of the working fluid, two controllers are implemented to track a set-point on subcooling at the condenser outlet by acting on the fan speed and the condensing pressure. Afterwards a comparative study is carried out to assess the relative potential of the two fluids using direct condensation. [less ▲]

Detailed reference viewed: 69 (6 ULiège)
Full Text
Peer Reviewed
See detailSizing and Operation of an Isolated Microgrid with Cold Storage
Dakir, Selmane ULiege; Boukas, Ioannis ULiege; Lemort, Vincent ULiege et al

in Powertech Milano 2019 Proceedings (2019, June 25)

Due to the technological developments and the advances of smart control, intermittent production from renewable energy sources can be better exploited locally in the context of a smart microgrid. Energy ... [more ▼]

Due to the technological developments and the advances of smart control, intermittent production from renewable energy sources can be better exploited locally in the context of a smart microgrid. Energy storage has a key role in achieving this task and batteries are the most suitable candidate. In this paper, a complementary solution is presented where excess electricity is used in a cold storage to produce ice which, when melting, supplies the cooling demand. A detailed model of each component is considered in order to simulate the operation of the entire system. The goal of this paper is the derivation of the optimal size of the different components to yield the minimum levelized cost of electricity. The methodology described is applied to a real case study in Marrakesh, and results illustrate that cold storage is able to reduce the total cost of energy in the context of an isolated microgrid. [less ▲]

Detailed reference viewed: 260 (100 ULiège)
Full Text
Peer Reviewed
See detailSizing and Operation of an Isolated Microgrid with Building Thermal Dynamics and Cold Storage
Dakir, Selmane ULiege; Boukas, Ioannis ULiege; Lemort, Vincent ULiege et al

in EEEIC Genoa 2019 Proceedings (2019, June 14)

A microgrid offers an efficient and cost-effective way to integrate renewable energy sources and to meet the energy needs of one or several entities, by mitigating the intermittent renewable generation ... [more ▼]

A microgrid offers an efficient and cost-effective way to integrate renewable energy sources and to meet the energy needs of one or several entities, by mitigating the intermittent renewable generation through the adequate use of storage systems and demand flexibility. It has been demonstrated that the use of an ice-based cold storage system is able to reduce the total cost of energy in the context of an isolated microgrid where the main goal is the procurement of the electrical and cooling demand. This requires every microgrid component to be modeled in detail to simulate the operations of the entire system. In this paper, we consider adding the possibility of controlling the temperature of buildings within predefined comfort limits, i.e. to add as an additional optimization variable the thermal storage of buildings. Additional flexibility and better utilization of the available renewable resources are thus acquired. As a result, the operating costs of the microgrid can be reduced by about 50%. [less ▲]

Detailed reference viewed: 60 (19 ULiège)
Full Text
Peer Reviewed
See detailInfrared imaging of a multi-zone condenser for heat transfer coefficients assessment
Dickes, Rémi ULiege; Dumont, Olivier ULiege; Lemort, Vincent ULiege

in Proceedings of ECOS 2019 (2019, June)

Although crucial for simulations, a proper identification of the convective heat transfer coefficients in multi-zone heat exchangers is a challenging task. While well instrumented thermal systems permit ... [more ▼]

Although crucial for simulations, a proper identification of the convective heat transfer coefficients in multi-zone heat exchangers is a challenging task. While well instrumented thermal systems permit to accurately record the energy balance in such components, the sole knowledge of the global heat transfer rate is not enough to reliably assess these coefficients. In this work, it is proposed to use the zones spatial distribution (i.e. the spatial fraction occupied by the liquid phase, the vapour phase and/or the two-phase regions) as a second identification criteria. An air-cooled condenser into which flows R245fa is considered as case study and a dedicated infrared imaging method is presented to assess the spatial distribution of its different phases. These new data, combined with standard heat transfer rate measurements, are exploited to identify the best heat transfer correlations pre-selected from the scientific literature. In order to further improve the model predictions, the original heat transfer correlations are ultimately adjusted so as to best fit both the global heat transfer rate and the zones distribution data. [less ▲]

Detailed reference viewed: 62 (15 ULiège)