Life cycle assessment of thermochemical energy storage integration concepts for a concentrating solar power plant

This paper presents an original life cycle assessment (LCA) of a concentrating solar power (CSP) plant with thermochemical energy storage (TCES). The studied CSP plant is a hypothetic solar tower plant with a Rankine power cycle, and the TCES material used is calcium hydroxide. Based on three proposed TCES integration concepts, detailed sizing and the associated emission inventory are performed for four main groups that constitute the CSP plant, including the solar field, the solar tower, the storage system and the power cycle. Various midpoint impact categories are evaluated using the IMPACT 2002+ method embedded in the SimaPro 7.3 software. A sensitivity analysis is performed to identify the most influencing elements of the CSP plant on the environmental impacts. LCA results show that the CSP plant with different TCES integration alternatives has comparable global warming potential (approximately 11 kg CO2.eq/MWh) and energy payback time (approximately 4 months). The additional environmental burden due to the addition of the TCES system is relatively small (about 30%). The use of calcium hydroxide for the TCES has noticeable midpoint impacts on the respiratory inorganics, the terrestrial ecotoxicity and the mineral extraction. Solar field group (heliostat mirrors) is generally the most sensitive and environmental impacting factor of the CSP installation. The Turbine integration concept has the smallest environmental impacts among the three concepts proposed

Intégration d’un procédé de Stockage Thermochimique à un cycle de Rankine, sous Energie solaire concentrée

The integration of a thermal energy storage (TES) system in a concentrated solar power (CSP) plant increases the daily production time and permits to overcome solar energy’s intermittent character. Among the three types of existing thermal storage technology (sensible, latent, thermochemical), thermochemical storage receives an increasing attention in recent years. Indeed, its high energy density and its capacity to store energy without heat losses during a long period of time make it the most promising candidate for CSP application.The principal objective of this PhD dissertation is to study the innovative thermochemical storage process, to propose conceptions for its integration into a CSP plant and to optimize the CSP plant’s overall efficiency. Various methodologies were used, including energy and exergy analyses based on the first and second law of thermodynamics, dynamic numerical simulations for the operation cycle and the life cycle analysis.Three integration configurations have been firstly proposed, studied and compared based on the energy and exergy analyses. Dynamics models for individual component of the system and the CSP plant as a whole were created and tested. These simulations made it possible to carry out a comparison or the integration configurations taking into account the inertia of the components and the variable solar irradiation. Several electricity production modes have also be tested (base production, peak production). Finally, a life cycle analysis was carried out in order to compare the three integration configurations based on environmental criteria.L’intégration d’un système de stockage thermique dans une centrale solaire à concentration augmente la durée de production journalière de la centrale tout en permettant de surmonter le caractère intermittent de l’énergie solaire. Parmi les trois types de stockage thermique existants (sensible, latent et thermochimique), le stockage thermochimique semble être le plus avantageux. En effet, sa grande densité énergétique et sa capacité à stocker de l’énergie sans pertes pendant une grande période de temps en font le candidat ayant le plus de potentiel pour équiper les centrales solaires à concentration. L’objectif principal de cette thèse est de développer un procédé innovant de stockage de l’énergie solaire et d’optimiser son intégration dans une centrale solaire à concentration par une démarche qui vise l’optimisation globale des performances de la centrale. Des méthodes numériques permettant de simuler le fonctionnement d’une centrale solaire ont été utilisées afin d’étudier le fonctionnement de la centrale et de déterminer ses performances.Trois configurations d’intégration ont été proposées, étudiées et comparées. Des études énergétiques et exergétiques statiques ont permis d’effectuer des comparaisons des configurations d’intégration en se basant sur les rendements énergétiques et exergétiques obtenus. Des modèles dynamiques de composants ont été créés afin de réaliser des simulations dynamiques des configurations d’intégration. Ces simulations ont permis d’effectuer une comparaison des configurations d’intégration en prenant en compte l’inertie des composants et le caractère variable de l’ensoleillement. Plusieurs modes de production d’électricité ont aussi pu être testés (production en base, en pic). Enfin une analyse du cycle de vie a été réalisée afin d’effectuer une comparaison des trois configurations d’intégration en se basant sur des critères environnementaux

Integration of a Thermochemical Storage process in a Rankine cycle, under solar concentrated Energy (In-STORES)

L’intégration d’un système de stockage thermique dans une centrale solaire à concentration augmente la durée de production journalière de la centrale tout en permettant de surmonter le caractère intermittent de l’énergie solaire. Parmi les trois types de stockage thermique existants (sensible, latent et thermochimique), le stockage thermochimique semble être le plus avantageux. En effet, sa grande densité énergétique et sa capacité à stocker de l’énergie sans pertes pendant une grande période de temps en font le candidat ayant le plus de potentiel pour équiper les centrales solaires à concentration. L’objectif principal de cette thèse est de développer un procédé innovant de stockage de l’énergie solaire et d’optimiser son intégration dans une centrale solaire à concentration par une démarche qui vise l’optimisation globale des performances de la centrale. Des méthodes numériques permettant de simuler le fonctionnement d’une centrale solaire ont été utilisées afin d’étudier le fonctionnement de la centrale et de déterminer ses performances. Trois configurations d’intégration ont été proposées, étudiées et comparées. Des études énergétiques et exergétiques statiques ont permis d’effectuer des comparaisons des configurations d’intégration en se basant sur les rendements énergétiques et exergétiques obtenus. Des modèles dynamiques de composants ont été créés afin de réaliser des simulations dynamiques des configurations d’intégration. Ces simulations ont permis d’effectuer une comparaison des configurations d’intégration en prenant en compte l’inertie des composants et le caractère variable de l’ensoleillement. Plusieurs modes de production d’électricité ont aussi pu être testés (production en base, en pic). Enfin une analyse du cycle de vie a été réalisée afin d’effectuer une comparaison des trois configurations d’intégration en se basant sur des critères environnementaux.The integration of a thermal energy storage (TES) system in a concentrated solar power (CSP) plant increases the daily production time and permits to overcome solar energy’s intermittent character. Among the three types of existing thermal storage technology (sensible, latent, thermochemical), thermochemical storage receives an increasing attention in recent years. Indeed, its high energy density and its capacity to store energy without heat losses during a long period of time make it the most promising candidate for CSP application. The principal objective of this PhD dissertation is to study the innovative thermochemical storage process, to propose conceptions for its integration into a CSP plant and to optimize the CSP plant’s overall efficiency. Various methodologies were used, including energy and exergy analyses based on the first and second law of thermodynamics, dynamic numerical simulations for the operation cycle and the life cycle analysis. Three integration configurations have been firstly proposed, studied and compared based on the energy and exergy analyses. Dynamics models for individual component of the system and the CSP plant as a whole were created and tested. These simulations made it possible to carry out a comparison or the integration configurations taking into account the inertia of the components and the variable solar irradiation. Several electricity production modes have also be tested (base production, peak production). Finally, a life cycle analysis was carried out in order to compare the three integration configurations based on environmental criteria

Dynamic modeling and simulation of a concentrating solar power plant integrated with a thermochemical energy storage system

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Heat transfer at the grinding interface between glass plate and sintered diamond wheel

Heat transfer analysis is of great importance for temperature prediction during grinding. Indeed the grinding parameters have to be adjusted to accelerate the manufacturing process while minimizing thermal damage to the workpiece. The temperature survey is especially critical for the grinding of glass material because of its low thermal conductivity inducing high temperature rise. In our study, temperatures at different locations in the sintered diamond composites of the grinding wheel are measured using thermocouples and a radio transmission technique. The glass temperature is measured using thermocouple strips on both side of glass plate, the grinding wheel providing the electrical connection between them. Results during grinding with a 6500 rpm rotation velocity shows temperature lower than 80 degrees C inside the grinding wheel while temperature up to 900 degrees C is found on glass. An inverse approach is used to compute the wall heat flux and temperature at the wall of the grinding wheel using a 2D axisymmetric heat transfer model. A 1D non linear heat transfer model including conduction and radiation is used to obtain the wall heat flux of the glass material. Knowing temperatures and heat fluxes on both side of the interface, one deduces information on thermal contact resistance, generated heat flux and partition ratio. So, the heat generated by the grinding is estimated between 223 and 399 W depending on the grinding process conditions and is localized on the glass side of the interface. The thermal contact resistance at the glass/sintered diamond composites figures out to be very high with a value greater than 3.8 10(-3) m(2)K W-1. (C) 2016 Elsevier Masson SAS. All rights reserved

Technical data for concentrated solar power plants in operation, under construction and in project

This article presents technical data for concentrated solar power (CSP) plants in operation, under construction and in project all over the world in the form of tables. These tables provide information about plants (e.g., name of the CSP plant, country of construction, owner of the plant, aim of the plant) and their technical characteristics (e.g., CSP technology, solar power, area of the plant, presence and type of hybridization system, electricity cost, presence and type of TES, power cycle fluid, heat transfer fluid, operating temperature, operating pressure, type of turbine, type and duration of storage, etc.). Further interpretation of the data and discussions on the current state-of-the-art and future trends of CSP can be found in the associated research article (Pelay et al., 2017) [1]