Antonio Lecuona

• Professor
• Professor (Full) at University Carlos III de Madrid

Spain has one of Europe’s most extraordinary biodiverse environments and a significant risk of fires in its forests. At the same time, rural areas are affected by several challenges, such as desertification, population decrease, and loss of income. Fortunately, some green sparks arise on the horizon. Among them, we use critical enabling technologie...

Smart cities will be smart if they improve their citizens’ quality of life; to do so, it is essential to listen to citizens and collaborate with service and technological companies. For that, digitalization seems essential. Environmental management systems are complex and expensive. If their lifecycle costs are reduced, these systems would be more...

The public purchase of innovation (PPI) is a type of public purchase that can contribute to sustainability in a significant way. Purchasing solar-powered energy systems can be a social innovation, bringing several opportunities for improving health, encouraging local entrepreneurship, building resilience, and promoting sustainable development. In t...

The paper offers innovative cooking utensil designs for remote, isolated, and even peri-urban communities at a low price, with high reliability and simple construction. It can alleviate energy poverty and improve food security. This utensil uses only local solar energy directly and allows comfortable indoor cooking. This paper provides the design p...

he paper offers an innovative cooking utensil design for remote, isolated, and even peri-urban communities at a low price, with high reliability and simple construction. It can alleviate energy poverty and improve food security. This utensil uses only local solar energy directly and allows comfortable indoor cooking. This paper provides the design...

Parabolic trough collectors and linear Fresnel collectors are mature technologies for power production, and they are being recently applied to provide solar heat for industrial needs. Conventionally, they use a liquid as heat transfer fluid, either thermal oil or water, to carry heat from the receivers up to the point of conversion or delivery. Alt...

Although still uncommon, direct air heating inside a linear concentrating collector can be a suitable solution for industrial hot air production aiming at environmental sustainability and decarbonization. In order to demonstrate the technical feasibility and investigating the key features of the technology, an experimental prototype is installed an...

Thermal energy storage technologies offer a promising solution for reducing the mismatch between heat demand and solar heat supply. Heat storage has huge potential for application in solar facilities for process heat at medium temperatures, nowadays not much explored. In this study, a small-scale latent heat storage unit is implemented and experime...

In recent years many efforts are being made to replace fossil fuel with renewable energy sources in the industry, both for electricity and heat production. Several high-energy demanding processes use hot air as heat and moisture carrier in the low and medium temperature range, for which solar air heaters offer great potential. Among solar energy te...

An improved thermodynamic open Dual cycle is proposed to simulate the working of internal combustion engines. It covers both spark ignition and Diesel types through a sequential heat release. This study proposes a procedure that includes (i) the composition change caused by internal combustion, (ii) the temperature excursions, (iii) the combustion...

Linear Fresnel collectors offer great potential for producing solar heat for industrial processes, both on a small and large scale. Thermal oil, pressurized water, or steam are used as heat transfer fluid in most applications, due to their suitable thermal properties. A heat exchanger is required for thermal power delivery to the user unless the he...

The study analyzes an innovative concentrating solar thermal system aimed at the direct production of hot air for industrial applications. Air is heated inside linear Fresnel collectors in an open to atmosphere circuit, not requiring the use of a primary heat transfer fluid and a heat exchanger, with their associated cost and maintenance. Matching...

A 90 m2 LFC solar field was connected to a turbocharger. All the facility was heavily instrumented and it was demonstrated that 500 ºC downstream the receiver tubes was possible without damaging the selective coating. After expansion in the turbine, 300-400 ºC air temperature was available for consumption for drying, curing, dehydrating, or preheat...

Many industrial processes use hot air as a medium. This is especially relevant for drying. Nowadays, most of them consume fossil energy. This study analyses an innovative facility for direct solar heating of air up to 400 °C. For this aim, a medium-scale solar field of linear Fresnel collectors is proposed to heat ambient air inside it. No other de...

A 3 modules Linear Fresnel solar collector facility heats compressed air using an automotive turbocharger. The pumping and compressing power is delivered by the associate turbine, avoiding any external power consumption.

Los colectores solares de concentración son una tecnología adecuada para proporcionar calor a media temperatura. En este trabajo se presenta un diseño innovador para la generación solar directa de aire caliente para procesos térmicos industriales mediante colectores tipo Fresnel comerciales. El aire se utiliza como fluido caloportador, calentado de...

Among the solar technologies nowadays considered as renewable energy sources for industrial processes, concentrating solar collectors are receiving growing attention due to their capability of providing heat at higher temperatures than other solar collectors. This study focuses on the application of linear Fresnel collectors to directly produce hot...

Medium temperature heat required by industrial processes worldwide is mostly provided by consuming fossil fuels. Among renewable energy alternatives, concentrating solar collectors can provide medium temperature heat at decreasing costs, either for medium and small scale applications. Several high energy-demanding processes need hot air in the rang...

This study describes the development of a photovoltaic (PV) solar cooker with the aim of creating a utensil that not only respects the environment and uses renewable energy, but also helps those who live in the most depressed and remote areas of the planet to improve their living quality, health, as well as energy and food security. The design is c...

Parabolic concentrating solar collectors PTCs represent an alternative to fossil fuel as a medium temperature heat source for a variety of applications, either in medium and small scale facilities. This work presents an innovative solution using PTCs for driving an absorption machine AM. In the novel layout proposed, the working pair of the AM circ...

Medium temperature heat required by industry and food processing facilities worldwide is provided mainly consuming fossil fuel. Alternative renewable energy sources are needed to reduce the environmental impact of high energy-demanding sectors and prevent fuel scarcity. Among solar technologies, concentrating collectors enable to provide high and m...

Renewable energies, such as solar, wind or wave energies show intermittent production patterns that complicates their injection into an electrical grid. In order to overcome this inherent drawback, this paper proposes an innovative permanent storage system that uses both thermal and mass transfer internal processes based on absorption to store mech...

Integrating the vapor generator/separator of an absorption machine and the solar collector field is proposed as a means to reduce the cost and complexity of solar cooling and heating facilities. In order to further enhance the competitiveness of these facilities, some previous work on hybrid and combined absorption cycles is analyzed so that the pr...

This work offers a complete 1-D analytic modelling of the peak locking errors. Besides error assessment, this model allows for measurement correction. The paradigm of peak-locking is revisited. Expressions of the functional dependence of the error are obtained for two relevant components of a measurement: i) the local velocity average, and ii) the...

Burning wood or residues for cooking causes indoor air pollution that leads to illnesses and mortality in the third world. Deforestation and painful wood collection are also negative consequences of using firewood. Better burning than with traditional three-stones stoves, using improved cook stoves signify an improvement, but it is insufficient. So...

Two-phase gravity-driven and gravity-stratified flow regime inside a pipe, which is present in many engineering applications, is an attractive option for solar cooling/heating/power production using Rankine cycles, absorption cycles or any other thermodynamic application by means of vapor as working fluid. This paper offers a numerical model of thi...

Among the renewable energy technologies, concentrating solar collectors are receiving growing interest as power source for heat and electricity production worldwide. The recent development of small scale parabolic trough collectors, PTCs, suggests extending their application to medium and low temperature facilities configuring solar integrated abso...

This is the apparently only and first technical book on solar cooking and its application to reduce energy poverty.

Absorption is a technology many years old. Since the French scientist Ferdinand Carré built the first absorption machine in 1858, it has been intensively developed, and it now offers many possibilities of use. An absorption machine is able to transfer heat from a cold source to a hot sink consuming 112heat from an external third source, working as...

This book examines the key aspects that will define future sustainable energy systems: energy supply, energy storage, security and limited environmental impacts. It clearly explains the need for an integrated engineering approach to sustainable energies, based on mathematical, biogeophysical, and engineering arguments. Resilient and efficient alter...

The performance of a two-stage double-effect absorption machine for combined power and cold generation is proposed and studied theoretically, generating innovative schemes. The ammonia/lithium nitrate solution allows this cycle, consuming either solar thermal or residual heat. The machine is represented by means of a thermodynamic steady-state cycl...

This work measures the size distribution of the particles exiting a simple-design seeding generator. A simple model for the prediction of the droplet size mean diameter is checked against these measurements, giving good agreement. The main fields of use of these generators include tracer particles based optical measurements like Particle Image Velo...

This work proposes a simple alternative to current designs of liquid seeding generators into air, usually used in Particle Image Velocimetry (PIV), or other tracer particles based optical measurements. Air is injected inside a propylene glycol – water mixture through 0.5 mm discharging orifices bubbling in the solution. This fluid presents the adva...

This work proposes an improvement of the shadowgraphy technique by allowing for 3-D droplet/particle location and sizing in a volumetric measurement with a single camera.

The two-stage configuration of a double-effect absorption cycle using ammonia/lithium nitrate as working fluid is studied by means of a thermodynamic model. The maximum pressure of this cycle configuration is the same as the single-effect cycle, up to 15.8bars, being an advantage over the double-effect conventional configuration with three pressure...

Article available for free on ScienceDirect until July 8, 2015: http://authors.elsevier.com/a/1R2z33BJ-v4PVG This work investigates experimentally the adiabatic absorption of ammonia vapour into ammonia-lithium nitrate solution using a full cone nozzle and an upstream single-pass subcooler. Data are representative of the working conditions of adia...

The optimum instantaneous driving temperature of a solar cooling facility is determined along a day. The chillers compared use single effect cycles working with NH3/LiNO3, either conventional or hybridised by incorporating a low pressure booster compressor. Their performances are compared with a H2O/LiBr single effect absorption chiller as part of...

From thermodynamic principles, an estimation of the exhaust gas temperature in internal combustion engines is performed.

The numerical study of transient two-phase flows claims for high order temporal integration schemes. This is relevant when the system is subjected to temporal variations in the boundary conditions that represent physical fluctuations in the inlet conditions. In our case the approximate solution in the pressure drop and true void fraction may vary r...

This paper reviews relevant issues on solar cooking in order to define and evaluate an innovative layout of a portable solar cooker of the standard concentrating parabolic type that incorporates a daily thermal storage utensil. This utensil is formed by two conventional coaxial cylindrical cooking pots, an internal one and a larger external one. Th...

Energy needs for heating and cooling in Spain are of paramount interest in the context of the European roadmap to a decarbonized environment; because of that, it is highly desirable that more examples of district heating and cooling networks are developed. The present work evaluates the implementation of one of them into the climatic environment of...

This paper presents the experimental assessment of the adiabatic absorption of ammonia vapour into an ammonia–lithium nitrate solution using a fog jet nozzle. The ammonia mass fraction was kept constant at 46.08% and the absorber pressure was varied in the range 355–411 kPa. The nozzle was located at the top of the absorption chamber, at a height o...

This paper presents a numerical model of a single-effect absorption refrigeration cycle incorporating a triple purpose liquid-vapor ejector acting as pressure booster for refrigerant vapor, adiabatic absorber and controlled solution expansion valve. The promising ammonia-lithium nitrate solution is selected as working pair, being able to produce co...

In Plate Heat Exchangers it is important to determine the flow distribution and pressure drops, because they affect directly the performance of a heat exchanger [1]. This work proposes an incompressible, one-dimensional, steady state, discrete model allowing for variable overall momentum coefficients to determine these magnitudes. The model consist...

Many efforts have been made in order to adequate the production of a solar thermal collector field to the consumption of domestic hot water of the inhabitants of a building. In that sense, much has been achieved in different domains: research agencies, government policies and manufacturers. However, most of the design rules of the solar plants are...

This paper presents a numerical model of an ejector-absorption (single-effect) refrigeration cycle with ammonia–lithium nitrate solution as working fluid, operating under steady-state conditions. In this cycle, the ejector is located at the absorber inlet replacing the solution expansion valve. The liquid–gas ejector entrains refrigerant vapor from...

An experimental study of a thermochemical compressor with ammonia–lithium nitrate solution as working fluid has been carried out. This compressor incorporates a single-pass adiabatic absorber and all the heat exchangers are of the plate type: absorber subcooler, generator and solution heat exchanger. The thermochemical compressor has been studied a...

This paper presents the experimental heat transfer evaluation during subcooled and saturated boiling of ammonia–lithium nitrate solution in a fusion plate heat exchanger, acting as a vapor generator under operating conditions representative of single-effect absorption machines. The solution flow rate and outlet temperature were modified in the rang...

The multiple Δt strategy is an inexpensive procedure that can be implemented with any usual particle image velocimetry (PIV) set up. The only requirement is acquiring different series of PIV image pairs, setting a different time between laser pulses for each series. With this additional information, robust procedures for error assessment are possib...

Various researchers have developed models of conventional H2O-LiBr absorption machines with the aim of predicting their performance. In this paper, the methodology of characteristic equations developed by Hellmann et al. (1998) is applied. This model is able to represent the capacity of single effect absorption chillers and heat pumps by means of s...

This paper presents the effect that both the ammonia concentration in an ammonia–lithium nitrate solution and the absorber pressure have on the adiabatic absorption of ammonia vapour by droplets generated by a fog-jet injector. The injector ensemble is located at 205 mm from the bottom of the absorber. The solution has an ammonia mass fraction vary...

This study has been carried out with a building experimental solar facility based on a 9-year-old field of 50 m2 flat plate solar collectors located south of Madrid, Spain. Building domestic hot water production and heating and cooling applications were implemented in the facility. Experimental data corresponding to 100 operating variables (mainly...

This paper presents the experimental evaluation of the adiabatic absorption of ammonia vapour into ammonia–lithium nitrate solution using a flat fan nozzle and an upstream single-pass subcooler. Data are representative of the working conditions of adiabatic absorbers in absorption chillers. The nozzle was located at the top of the absorption chambe...

This paper proposes a method to sort experimental snapshots of a periodic flow using information from the first three POD coefficients. Even in presence of turbulence, phase-average flow fields are reconstructed with this novel technique. The main objective is to identify and track traveling coherent structures in these pseudo periodic flows. This...

At least two circumstances point to the need of postprocessing techniques to recover lost time information from non-time-resolved data: the increasing interest in identifying and tracking coherent structures in flows of industrial interest and the high data throughput of global measuring techniques, such as PIV, for the validation of computational...

An experimental research was performed on a solar facility with a nine-year-old, on-campus field with 50 m2 area of flat plate solar collectors. A transient model was developed, adapted to the characteristics of this facility and experimentally validated as described in Part I of this paper.The efficiency normalization curve (ENC) operating conditi...

The efficiency of a solar collector is a key factor for the performance of thermal facilities. As the weather conditions vary continuously during the day, the instant collector efficiency depends not only on the components employed in its construction but also on the actual environmental conditions, the hot water temperature and aging. An experimen...

The possibility of using different times between laser pulses (Δt) in a PIV (Particle Image Velocimetry) measurement of the same real flow field for error assessment has already been proposed by the authors in a recent paper Nogueira et al. (Meas Sci Technol 20, 2009). It is a simple procedure that is available with the usual PIV setup. In that wor...

The development of two and three-dimensional instabilities on a low Reynolds number co-flowing jets, methane-air diffusion flame subjected to simultaneous axial and azymuthal perturbations has been studied experimentally. The axial instability is triggered by introducing periodic, small amplitude, axial pressure pulses of a given frequency, while t...

This work analyzes the effect that particular operating conditions of a single effect H2O-LiBr adiabatic absorption system have on a plate-type solution heat exchanger efficiency. The corresponding influence of such efficiency on the performance of facility under study is evaluated. As a result of the design of experimental test facility, the funct...

This paper presents the analysis of the performance of a solar cooling facility along one summer season using a commercial single-effect water-lithium bromide absorption chiller aiming at domestic applications. The facility works only with solar energy using flat plate collectors and it is located at Universidad Carlos III de Madrid, Spain. The sta...

This paper presents a numerical model of single-effect absorption cycles with ammonia-lithium nitrate solution as the working pair and incorporating an adiabatic absorber. It is based on UA-ΔTlm models for separate regions of plate-type heat exchangers and it assumes an approach factor to adiabatic equilibrium. The results are offered as a function...

This paper presents the thermal and pressure-drop experimental evaluation of a fusion plate heat exchanger (PHE) during boiling conditions of a solution of lithium nitrate in ammonia. The data are representative of the working conditions of generators in single-effect absorption chillers. The solution flow rate and outlet temperature were modified...

Single-effect absorption refrigeration hybridized with mechanical vapor compression in a vapor circuit is known as the absorption cycle with an integrated booster compressor. In this study, the compressor is located between the evaporator and the absorber. This paper presents a numerical model of this cycle with ammonia-lithium nitrate solution as...

This paper unveils inherent limits on the dynamic range of the spatial scales that the PIV velocimetry technique is able to resolve in presence of turbulence. This provides PIV setup guidelines to take into account for optimizing the measurement parameters. If these physical constraints are not taken into account, deficiencies on the information co...

The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide–water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the per...

PIV (particle image velocimetry) is a measurement technique with growing application to the study of complex flows with relevance to industry. This work is focused on the assessment of some significant PIV measurement errors. In particular, procedures are proposed for estimating, and sometimes correcting, errors coming from the sensor geometry and...

The lean premixed prevaporized (LPP) burner concept is now used in most of the new generation gas turbines to reduce flame temperature and pollutants by operating near the lean blow-off limit. The common strategy to assure stable combustion is to resort to swirl stabilized flames in the burner. Nevertheless, the vortex breakdown phenomenon in react...

This work presents and characterizes the existence of two different regimes in the spreading and break-up of liquid flat-fan sheets when discharging in low-density atmospheres. The motivation of the study is the improvement on the absorption phenomena of lithium bromide aqueous solution when discharging in a 600–1,500Pa water vapor environment. Thi...

Air conditioning (AC) is spreading in Spain, where summer weather reaches temperatures above 35 °C. This causes the increase, not only of electricity consumption, but also organic refrigerant leakage due to the use of vapour-compression machines.An experimental research on solar absorption cooling has been carried out at Universidad Carlos III de M...

Particle image velocimetry with local field correction (LFC PIV) has been tested in the past to obtain two components of velocity in a two dimensional domain (2D2C). When compared to conventional correlation based algorithms, this advanced technique has shown improvements in three important aspects: robustness, resolution and ability to cope with l...

Solar thermal installations can provide a significant contribution to the energy needs of cooling demand of single family buildings. Unfortunately oversizing facility elements is not uncommon. Most of the design flaws concern collector field or auxiliary elements, such as backup boilers or electric resistances inside storage devices. This leads to...