Concept d’une minicentrale électro-thermo-solaire hybride adaptée aux pays en voie de développement.

Daniel Favrat, El Hadj Malick Kane
2000
Article de conférence

Résumé

This paper presents the analysis of an original design of small hybrid solar plant using Organic Rankine Cycles with hermetic scroll expander- generators. The hot supply is provided from vacuumed collector tubes along the focal line of solar concentrators made of mirror bands fixed on a plane surface (CEP). The plant is integrated with a cogeneration Diesel engine unit to ensure power availability independently from the variations of solar radiation. It is primarily intended for isolated sites in developing countries. Measurements on the power unit of 13 kWel show an excellent behavior over a broad range of parameters with an efficiency of the order of 18% (50% exergetic efficiency), which is very promising, particularly when considering that the concept of superposed cycles will allow operations at higher supply temperatures with further technological developments.

Official source

https://infoscience.epfl.ch/record/53382?ln=fr

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Concepts associés

Chargement

Publications associées

Chargement

Thermal solar power plants using Rankine cycles closely approach the present economical electricity prices, at least in the large power range. One of the advantages currently explored is the integration with other fuel based technologies in order to ascertain a given power disponibility and to increase the use of the investment in the power unit. This paper presents the analysis of an original design of small hybrid solar plant including: a) A power unit of Superposed Organic Rankine Cycles equipped each with hermetic scroll expander-generators (scroll orbital type) with an installed total capacity of 12 kWe. Each turbine works with a new lubrication system whose feasibility, simplicity and robustness are experimentally confirmed. b) A Solar Plate Concentrating Reflector (CEP) unit equipped with mirror bands fixed on a plane surface which focalize solar energy on the vacuumed collector tubes. Only one array of 50 m2 (against 100 m2) of the solar field is assembled and tested. The realization of the second line of collectors is planned. c) A 15 kWel cogeneration Diesel engine unit to ensure power availability independently from the variations of solar radiation with a self regulation system. A total thermal power of 34.5 kW can be recovered. The following performances are expected: 12% of efficiency for the solar operation mode (Electricity power / Solar thermal incident) and 22% for the solar hybrid operation mode (Total Electricity Power / Solar thermal incident + Fuel Power). This concept presented can be used for several applications such as industrial waste heat recovery, domestic cogeneration etc… - - - - - - - - - - - - - - - - - Dans le cadre des projets précédents, le LENI en collaboration avec COGENER et avec le support de l’Office Fédéral de l’Energie (OFEN) a étudié le concept d’une centrale électro-thermo-solaire de 10 kWe. Cependant l’analyse des coûts globaux de la centrale, dimensionnée à la base pour fonctionner avec du solaire seul, avait conduit à l’option d’une réduction de la taille du champ de capteurs solaires à 96.4 m2 au lieu des 159 m2 initialement prévus. Le cycle thermodynamique de conversion devait être réadapté en tenant compte d’une source d’appoint thermique pouvant garantir la disponibilité de puissance. D’où l’idée de réaliser une hybridation au moyen d’une unité moteur de cogénération qui, de toute façon, représente une des voies parmi les plus prometteuses d’introduction du solaire par la production d’électricité. Le présent projet vise deux points essentiels. D’une part développer des outils de recherche nécessaires pour le développement d’un système solaire énergétique intégré, et d’autre part valoriser ces outils dans le cadre d’une unité pilote de centrale hybride (HSPS : Hybrid Solar Power System) permettant de mesurer ses performances et de caractériser son potentiel d’amélioration. Différentes études (modélisation des composants, méthode de dimensionnement, programme Solar Power System...) présentées en détail dans le rapport précédent intitulé "CSIP3: Projet détaillé d’une minicentrale pilote électro-thermo-solaire de 10 kWe" ne seront pas reprises. L’analyse du concept global de la centrale hybride a été présentée dans le cadre de la conférence CISBAT99, Concept d’une minicentrale électro-thermo-solaire hybride adapté au pays en voies de développement. La description de certaines parties de cette publication (la machine thermique, l’unité de cogénération...) sera complétée avec des supports techniques présentés en annexes. Pour les aspects du champ de capteurs, nous faisons références au rapport fourni par COGENER.

1999

Chargement

SPS: Projet d'une minicentrale pilote électro-thermo-solaire de 10 KWe.

Daniel Favrat, El Hadj Malick Kane

This report presents the field tests synthesis of a small Hybrid Solar Power Plant integrating three technologies : hermetic volumetric scroll expander - generators working with two superposed Organic Rankine Cycles (ORC) a cogeneration group composed by a Diesel engine coupled with an asynchronous generator with heat recovery at two levels of temperature and a solar field made of plate concentrators. This type of hybrid power plant is mainly intended for rural electrification purposes in developing countries or cogeneration in applications like heating swimming pools in other countries. After having been tested separately, the three main components of the plant (Concentrators, ORC and cogeneration group) have been coupled in a field on the EPFL campus in Lausanne (Switzerland) in order to allow experimentation of the entire installation with real conditions. The general concept is promising, thermal cycles being quite robust and adapting well to the very variable solar conditions, and this for the two working modes (Solar and Hybrid). In terms of performances, results have been encouraging, even if improvements are still necessary. Expanders worked at part load, the concentrating surface having been under-dimensioned and there are no doubts results could be achieved with better adaptation between these two elements. In hybrid mode, fuel energy was transformed up to 40.5 into electricity, opening good perspectives for the future including with other cogeneration technologies like micro gas turbines or medium to high temperature fuel cells.

2001

Chargement

Small Hybrid Solar Power System

Daniel Favrat, El Hadj Malick Kane, Diego Larrain

This paper introduces a novel of mini-hybrid solar power plant integrating a field of solar concentrators, two superposed Organic Rankine Cycles (ORC) and a (bio)Diesel engine. Turbines for the organic Rankine Cycles are hermetic scroll expander-generators. Sun tracking solar collectors are composed of rows of flat mirror bands (CEP) arranged in a plane, which focus the solar energy onto a collector tube similar to those used in SEGS plant in California. The waste heat from both the exhaust gases and block cooling of the thermal engine are also heat sources for the ORCs. Such units are considered to meet electricity, cooling and pumping needs of remote settlements in the sun belt areas or on special sites requiring low temperature heating such as swimming pools or greenhouses. The thermal engine guaranties a minimum level of both power and heat availability at night or during cloudy periods. Laboratory tests, made with the superposed ORCs only, confirmed adequate operational characteristics with good performances over a broad range of conditions. A few preliminary tests on the site of the solar power plant when coupled with the engine confirmed a reasonable behavior and the interest of the concept even at part load or during sharp variations of the thermal supply. The performances are satisfactory for a hybrid solar plant of this power range (10 to 25 kWe) and working so far with rather low temperature solar supply (165°C). First Law efficiencies of conversion in hybride mode is of the order of 41% when considerating only the fossil fuel input (total electrical power / LHV of the fuel). This already represents an efficiency increas of close to 50% compared to the Diesel engine alone. These results are encouraging particularly when one considers that excellent prospects exist for further increasing the supply temperature. However due to an over sizing of the turbines and a solar collector efficiency lower than expected, the tests reported here were made at very partial load and the efficiency in mode "solar only" was limited to 7.74%.

2001

Chargement

1999

Small Hybrid Solar Power System

Daniel Favrat, El Hadj Malick Kane, Diego Larrain

2001