Cristina Prieto

Cristina Prieto
Abengoa · Solar energy department

PhD in Process Engineering

About

67
Publications
15,754
Reads
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1,611
Citations
Citations since 2016
58 Research Items
1602 Citations
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Additional affiliations
November 2017 - present
Universidad de Sevilla
Position
  • Professor (Associate)
January 2007 - present
Abengoa
Position
  • Managing Director
Education
September 2013 - September 2016
Universitat de Lleida
Field of study
  • Energy Engineering
September 2008 - June 2009
Universidad de Navarra
Field of study
  • Advanced Management Program
September 1992 - June 1999
Universidad de Sevilla
Field of study
  • Process Engineering

Publications

Publications (67)
Article
Two high corrosion resistant super-alloys, alloy 800H and alloy 625, were evaluated for corrosion compatibility with molten nitrate salts at 565 °C under air atmosphere since these super-alloys are possible candidates for the manufacturing of molten salts solar receivers in the CSP tower technology. Both alloys are tested in two different molten ni...
Article
One of the biggest challenges of concentrating solar power (CSP) is achieving cost-reduction in the thermal energy storage (TES) system. Operating conditions of molten salt CSP plants includes intermittent exposure of the TES tanks materials (i.e., carbon steel, stainless-steel) in contact with molten salt (NaNO3–KNO3). This manuscript evaluates th...
Article
Although studies on the levelized cost of energy (LCoE) of concentrating solar power (CSP) plants were published in recent years, these studies were not related to the environmental impact generated. To fill this literature gap, this study compares the environmental impacts generated by four tower solar thermal plants with different storage capacit...
Article
Full-text available
Thermal energy storage (TES) allows the existing mismatch between supply and demand in energy systems to be overcome. Considering temperatures above 150 °C, there are major potential benefits for applications, such as process heat and electricity production, where TES coupled with concentrating solar power (CSP) plants can increase the penetration...
Article
Full-text available
Concentrating solar power (CSP), also known as solar thermal electricity (STE), is increasing its deployment worldwide. One of the potential ways to decrease costs in CSP plants is the improvement of corrosion resistance between the heat transfer fluid (HTF) and storage materials, and the materials used for pipes, tanks, containers, and receivers....
Article
Thermal energy storage (TES) increases concentrating solar power (CSP) plant capacity factors, but more important, improves dispatchability; therefore, reducing the capital cost of TES systems is very important to reduce cost of energy and serve as an enabler for commercial solar power plants. After presenting the concept of a novel cascade PCM con...
Article
This study evaluates the proposal of a concrete storage tank as molten salt container, for concentrating solar power applications. A characterization of the thermal and mechanical properties including compression resistance, density, thermal conductivity and chemical degradation were evaluated in a pilot plant storage tank in contact with solar sal...
Article
Full-text available
Steam accumulation is one of the most effective ways of thermal energy storage (TES) for the solar thermal energy (STE) industry. However, the steam accumulator concept is penalized by a bad relationship between the volume and the energy stored; moreover, its discharge process shows a decline in pressure, failing to reach nominal conditions in the...
Article
Full-text available
Bibliometric analysis is a key study in order to elucidate the relevance of a research field. This study will point out the main evolution of the research performed in a topic considering the significance of each sub-topic. This study aims to perform a bibliometric analysis in concentrating solar power (CSP) technology. CSP had a first commercial w...
Article
Full-text available
The circular economy can be promoted as a solution to support the sustainability market position of renewable energy systems. To design a circular and sustainable system, a structured approach is needed. The present study develops a methodology framework for sustainable circular system design (SCSD), aiming to assess thermal energy storage (TES) te...
Article
Full-text available
Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out and compared with a reference CSP plant without storage. Results show that the...
Article
Full-text available
The high intermittency of solar energy is still a challenge yet to be overcome. The use of thermal storage has proven to be a good option, with phase change materials (PCM) as very promising candidates. Nevertheless, PCM compounds have typically poor thermal conductivity, reducing their attractiveness for commercial uses. This paper demonstrates th...
Chapter
This chapter describes the principles of heat storage systems, with emphasis on those currently used sensible storage media an industrial scale: direct storage in power tower, two tanks indirect storage, and thermocline systems. This chapter provides information on both organic and inorganic commercial heat storage liquid media, such as oils and mo...
Chapter
The option to supply electricity on demand is a key advantage of solar thermal power plants with integrated thermal storage. Diurnal storage systems providing thermal power in the multi-MW range for several hours are required here, the temperature range is between 250°C and 700°C. This chapter gives an overview of the various basic concepts for ene...
Chapter
Latent thermal energy storage is a technology with very high potential to increase the efficiency of energy systems. In this article, this technology is presented for high temperature applications (higher than 120 °C), which include solar thermal electricity, solar cooling for air conditioning systems, and industrial applications, including waste h...
Article
Thermal energy storage is recognized as a key technology in the energy transition the world is facing today. But the main technical barrier this technology has to achieve wider deployment the low thermal conductivity of the materials used, the so-called phase change materials (PCM). This paper presents a new concept for thermal conductivity enhance...
Article
Solar thermochemical water splitting was successfully demonstrated with monolithic receiver-reactors in field at 50 kW scale. Since monolithic receiver-reactors are limited in size, several of the reactors will have to be combined in receiver-reactor arrays for large-scale plants. In this study, the yearly performance of solar thermochemical plants...
Article
Full-text available
Industries with fast-developing technologies and knowledge-intensive business services rely on the development of scientific knowledge for their growth. This is also true in the renewable energy industry such as in concentrating solar power (CSP) plants, which have undergone intense development and expansion in the last two decades. Yet knowledge g...
Article
Pyromark is a silicone-based black paint that is commonly used in concentrated solar power plants because of its relatively high absorptivity. However, it has very low durability, which decreases the optical performance of the surfaces coated with this paint over time, thus reducing the thermal efficiencies of these plants. Recent studies have trie...
Technical Report
Full-text available
The purpose of this document is to analyze the state-of-the-art of the CSP technology, focused on the solar tower configuration, and the possibility of integrating a supercritical CO2 (sCO2) cycle to substitute the traditional steam cycle. To that end, the document is divided in six sections. The first section presents a description of the fundamen...
Article
Postmortem tests were performed over components removed from the TES-PS10 pilot plant after almost four years of continuous operation being exposed to solar salts under representative commercial operation conditions. Accordingly, corrosion performance of plates sections extracted from both storage tanks and samples cut from the hot molten salts pum...
Article
Concentrated solar power (CSP) is today recognized as a unique renewable energy for electricity generation due to its capability to provide dispatchable electricity incorporating thermal energy storage (TES). Molten salts TES is the most widespread technology in commercial CSP but the industry is looking for cheaper and more efficient TES systems a...
Article
Concentrated solar power (CSP) is not currently cost competitive with conventional power generation or other solar energy technologies, but it is attractive because it integrates commercially viable large-scale thermal energy storage (TES). To improve performance and reduce costs, supercritical carbon dioxide (s-CO2) power cycles have been proposed...
Article
Full-text available
Current CSP plants that operate at the highest temperature use molten salts as both Heat Transfer Fluid (HTF) and Thermal Energy Storage (TES) medium. Molten salts can reach up to 565 °C before becoming chemically unstable and highly corrosive. This is one of the higher weakness of the technology. Solid particles have been proposed to overcome curr...
Article
Full-text available
Parabolic trough collector (PTC) technology is currently the most mature solar technology, which has led to the accumulation of relevant operational experience. The overall performance and efficiency of these plants depends on several components, and the heat transfer fluid (HTF) is one of the most important ones. Using molten salts as HTFs has the...
Article
Thermal energy storage (TES) systems are key components of concentrating solar power plants in order to offer energy dispatchability to adapt the electricity power production to the curve demand. Nitrate molten salts are the storage media used today in concentrated solar power plants. They are also used as heat transfer fluid (HTF) in the molten sa...
Article
The eutectic mixture Li2CO3-Na2CO3-K2CO3 is investigated as a high temperature heat transfer fluid and storage medium alternative for molten salt solar thermal power plants. This salt has an operating temperature range of 400ºC – 700ºC, enabling the use of higher temperature/efficiency power cycles. However, this carbonate mixture is known to therm...
Article
Full-text available
The aim of this study is to perform a review of the state-of-the-art of the reactors available in the literature, which are used for solid–gas reactions or thermal decomposition processes around 1000 °C that could be further implemented for thermochemical energy storage in CSP (concentrated solar power) plants, specifically for SPT (solar power tow...
Article
Nowadays, the most matured thermal energy storage (TES) technology for Concentrated Solar Power (CSP) plants is the use of molten solar salts (60 wt% NaNO3 – 40 wt% KNO3), but the thermal decomposition of nitrate salts can result in changes in the composition of molten salts or potential risks of NOx emissions. Up to now, all studies on the decompo...
Article
Thermal energy constitutes up to 90% of global energy budget, centering on heat conversion, transmission, and storage; therefore, the technology for harvesting solar energy worth to be developed. One of them is the concentrated solar power (CSP) solar towers where sun-tracking heliostats reflect solar radiation to the top of a tower where the recei...
Article
A387 Gr 91 Cr-Mo alloy corrosion compatibility with LiOH-KOH mixture was evaluated at 315 °C (Test#1) and 360 °C (Test#2). This alloy is studied for a techno-economical optimization of a steam-PCM heat exchanger proposed in the thermal energy storage (TES) system of a direct steam generation (DSG) facility. The corrosion damage was analyzed with vi...
Article
Renewable energies are main players to ensure the long-term energy supply. Solar power plants with thermal energy storage (TES) are one of the available renewable technologies which have more potential. Nowadays, there are still several aspects in the design and operation of these power plants which need to be improved, such as the correct operatio...
Article
Thermal energy storage (TES) in molten salts is the storage dominating technology in solar power applications today. In two-tank molten salt storage systems energy density ranges from 30 to 70 kW h/m³ are achievable. The salt material used is a binary system, composed of 60% NaNO3 and 40% KNO3. In the 8 MWhth pilot plant built and tested by Abengoa...
Article
Existing commercial parabolic trough power plants use thermal oil as a heat transfer fluid, with working temperatures in the region of 400 °C. In order to achieve more efficient generating systems, a second generation of parabolic troughs that operate at temperatures higher than 400 °C is being developed. One possibility Abengoa Solar is assessing...
Article
Thermal energy storage systems are key components of concentrating solar power plants in order to offer energy dispatchability to adapt the electricity power production to the curve demand. This paper presents a review of the current commercial thermal energy storage systems used in solar thermal power plants: steam accumulators and molten salts. I...
Conference Paper
Full-text available
The present work provides an overview of activities performed in the framework of the EU-funded collaborative project RESTRUCTURE, the main goal of which was to develop and validate a compact structured reactor/heat exchanger for thermochemical storage driven by 2-step high temperature redox metal oxide cycles. The starting point of development pat...
Article
Full-text available
The present work provides an overview of activities performed in the framework of the EU-funded collaborative project RESTRUCTURE, the main goal of which was to develop and validate a compact structured reactor/heat exchanger for thermochemical storage driven by 2-step high temperature redox metal oxide cycles. The starting point of development pat...
Article
The selection of a proper heat transfer fluid (HTF) is a key factor to increase the efficiency of concentrated solar power plants and therefore, to reduce their internal associated CAPEX (capital expenditures of developing and constructing a plant, excluding any grid-connection charges) and OPEX (operating expenditures from the first year of a proj...
Article
The increasing role of concentrated solar power (CSP) within the renewable energy portfolio is attributed to the possibility of integrating thermal energy storage (TES) systems. Then, CSP technology has become one of the most interesting clean options to deliver dispatchable power on demand. Nowadays, commercial facilities use high quality solar sa...
Article
Phase change materials (PCM) is one of the most interesting solutions to be used in thermal energy storage (TES) systems for direct steam generation (DSG) thermosolar facilities. Properties such as high energy density and energy storing/delivery at constant temperature bring PCM based systems in excellent candidates for DSG facility storage units....
Article
Concentrated solar power (CSP) generation is becoming a very important player within the renewable energy sector thanks to increased introduction of these facilities into the conventional electricity market. CSP plants become dispatchable when integrating thermal energy storage (TES) systems which allow electricity production at any time of the yea...
Article
In 2008, following its R&D strategy roadmap for Concentrated Solar Power, Abengoa designed, built and tested a unique Molten Salts pilot plant at the representative scale of 8 MWhth, coupled with a trough oil loop. The objectives of this project were based on evaluating the technology at a scale at which the results are sufficiently representative...
Article
Concentrated solar power plants (CSP) combined with thermal energy storage (TES) offers the benefit to provide continuous electricity production by renewable energy feed. There are several TES technologies to be implemented, being the thermochemical energy storage the less studied and the most attractive since its volumetric energy density is 5 and...
Article
Phase change materials (PCM) are able to store thermal energy when becoming liquids and to release it when freezing. Recently the use of PCM materials for thermal energy storage (TES) at high temperature for Concentrated Solar Power (CSP) technology has been widely studied. One of the main investigated problems is the improvement of their low therm...
Article
Solar power plants have been deployed in the last 20 years, so the interest in evaluating their performance is growing more and more. In these facilities, thermal energy storage is used to increase dispatchability of power. The two-tank molten salts storage system with “solar salt” (60 wt.% NaNO3 and 40 wt.% KNO3) is the one commercially used today...
Article
Despite the fact that there are some commercial concentrated solar power plants worldwide, there is currently a lack of experimental reports about the operational characteristics of this type of plants. Therefore, a two-tank molten salts thermal energy storage (TES) pilot plant at the University of Lleida (Spain) was used to analyze charging and di...
Conference Paper
Full-text available
Among systems proposed as suitable for thermochemical heat storage (TCS), redox oxides merit significant attention for high temperature applications in Concentrating Solar Power (CSP) plants. The specific enthalpy of the reaction is a key parameter to establish the storage capacity of the system. Consequently, there is considerable practical intere...
Article
This paper presents the importance of the thermal losses in the performance evaluation of thermal storage systems. In order to reinforce this statement, an evaluation of a pilot plant whose size is sufficiently representative for the extrapolation of results at larger scales has been carried out. The evaluation of the heat losses of a molten salt p...
Article
To be able to extend the operation of a solar power plant (CSP) up to 15 h, thermal energy storage (TES) is necessary. But TES also provides more versatility to the plant and makes its reliance during operation hours more dependable. On the other hand, due to the different CSP configurations, a broad spectrum of storage technologies, materials and...
Conference Paper
The design and building of two thermal energy storage (TES) pilot plants to be used for concentrated solar power (CSP) applications is explained and compared. Both pilot plants are based on a two-tank molten salt storage technology (composed by a hot and a cold tank) which works under a TES process. This process has three main steps: charge, storag...
Patent
The invention relates to a storage tank for non-pressurised heat transfer fluids, which has an internal layer (2) of insulating concrete having a thermal conductivity below 1.05W/mK. The tank also has an external layer (1) of concrete having a standard compressive strength between 20 and 50MPa. The tank does not require pre-tensioning or post-tensi...
Patent
The invention relates to a heat storage method and system for a steam generation plant, and to the solar plant comprising said system. The method according to the invention minimises the charging and/or discharging effect in conditions that differ from the nominal conditions by means of a system consisting of three blocks: i) a saturating block bas...
Patent
The invention relates to a thermal storage system which includes a container (1) in which are arranged: a) a set of capsules (3) which form a porous bed and contain a phase-change material having high energy density and consisting of inorganic salts; and b) a matrix (2) which consists of a metal phase-change material having high thermal conductivit...
Article
Thermal energy storage (TES) is recognised as a key technology for further deployment of renewable energy and to increase energy efficiency in our systems. Several technology roadmaps include this technology in their portfolio to achieve such objectives. In this paper, a first attempt to collect, organise and classify key performance indicators (KP...
Patent
The invention relates to the composition of a self-compacting concrete with high compressive strength. Said concrete reaches compressive strength levels of higher than 100 MPa after 28 days, maintaining its self-compacting property. The invention also relates to the method for producing the high-strength self-compacting concrete and to the use of s...
Patent
The invention relates to a refractory concrete composition with low thermal conductivity and increased resistance, to the method for the production thereof, and to the use of same as a structural concrete coating for elements subjected to high temperatures which are simultaneously required to bear structural compression forces, such as nuclear reac...
Article
Full-text available
Existing commercial parabolic trough power plants use thermal oil as a heat transfer fluid, with working temperatures in the region of 400 °C. In order to achieve more efficient generating systems, a second generation of parabolic troughs that operate at temperatures higher than 400 °C is being developed. One possibility, Abengoa Solar is assessing...
Patent
The invention relates to a portable mixing platform for producing a heat-transfer fluid on site and on an industrial scale, said fluid consisting of a eutectic mixture of diphenyl (DP) and diphenyl oxide (DPO). The platform includes a device that stores DPO in a liquid state, a device for supplying DP in a solid state, a mixing device in which both...
Patent
Tank for the thermal storage of a pressurized fluid and method for the construction thereof, the fluid being a gas or liquid at high pressures and temperatures, which comprises an external layer (1) of high-strength post-tensioned concrete, and an intermediate layer (2) of post-tensioned refractory concrete that acts as a thermal barrier between th...
Patent
A concentrating solar power plant ( 200 ) utilizes two heat transfer fluids. A first heat transfer fluid is heated in a field ( 203 ) of concentrating solar collectors. A second heat transfer fluid is heated through a heat exchanger ( 204 ) using heat imparted from the first heat transfer fluid. The second heat transfer fluid is then further heated...
Patent
The invention relates to a composite material for storing heat energy at high temperatures (225 to 488°C), formed by a porous carbon structure at least partially filled with LiOH/KOH, in which a large amount of heat energy can be stored or released very quickly. The carbon structure is characterized by high volumetric thermal conductivity, low dens...

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