Alberto Coronas

Universitat Rovira i Virgili | URV · Department of Mechanical Engineering

Today, the petroleum sector is considered among the most polluting industries. The gas flaring impacts directly the air pollution due to the rejected energy with high temperature, volatile organic compounds as well as greenhouse gas emission. Therefore, the valorisation of flare gas is investigated as a potential solution to decarbonise the downstr...

The aim of this study is to analyze the feasibility of the single-effect H2O/LiBr absorption heat pump cycle to produce combined heating and cooling. To achieve this, first, the main changes that the absorption cycle requires are described in comparison with the conventional single-effect absorption chiller. Then, the cycle’s operational limits in...

World population growth, climate change, and water scarcity will increase food vulnerability, especially in developed countries. Therefore, increasing crop productivity is one of the main challenges to be addressed in the next years. In this sense, intensive horticulture will play a key role to supply the growing demand for food. In greenhouse farm...

World population growth, climate change, and water scarcity will increase food vulnerability, especially in the developed countries. Therefore, increasing crop productivity is one of the main challenges to be addressed in the next years. In this sense, intensive horticulture will play a key role to supply the growing demand for food with high produ...

Ionic liquids are promising absorbents for closed absorption heat pumps because of their suitable properties, such as low vapor pressure, specific solubility for the refrigerants, etc., although they also present some drawbacks as high viscosity and low mass diffusivity. As the absorber is one of the key components of the absorption heat pumps, it...

This paper presents an experimentally validated, dynamic model of a hybrid liquid desiccant system. For this purpose, we developed new components for the air-solution contactors, which are of the non-adiabatic falling-film type with horizontal tubes (made of improved polypropylene) and the solution tanks. We also provide new experimental correlatio...

Absorption chillers require precise models for their control and optimization. The present work analyzes the behavior of a 10-kW absorption chiller by means of four different methods that use the external fluid temperatures to situate the machine operating conditions, either through a characteristic temperature difference or through the COPcarnot....

This paper presents the experimental investigation and development of a general semi empirical scroll expander model for different working fluids. Initially, the characterization and modelling of a scroll expander with R134a working fluid is performed. The influence of key operating variables on the main performance indicators such as isentropic ef...

Compression/resorption refrigeration systems are similar to conventional vapor compression systems but using zeotropic mixtures with large boiling temperature difference, similar to the refrigerant/absorbent mixtures used in absorption technology. A resorber and a desorber replace the conventional condenser and evaporator, respectively. As the satu...

In applications where latent loads or ambient humidity are high, liquid desiccant systems combined with vapor compression systems are a suitable alternative to conventional HVAC systems because they can efficiently control air temperature and humidity. In this sense, an optimal integration in terms of working conditions and energy management of bot...

Ammonia/water absorption–resorption refrigeration systems are an interesting technological alternative to conventional absorption systems thanks to their additional degree of freedom, which makes operation more flexible and can significantly reduce the typically high working pressure, so cheaper assembly materials can be used. This paper aims to re...

The water activities of sodium molybdate in aqueous solutions at T = (303.15, 313.15, 323.15 and 333.15) K were determined, using vapor pressure osmometry. The range of salt concentration was from 0.06 to 2.2 mol kg⁻¹. The results show that sodium molybdate has a significant effect on the water activity. Values of the vapor pressure, osmotic and ac...

This paper presents a theoretical and experimental study of the adiabatic absorption process of ammonia into an ammonia/water solution using a polymeric hollow fiber membrane module (Liqui-Cel G501 2.5x8 Extra-Flow) as a contactor. An experimental test bench was designed and built and the effect of the subcooling conditions of the inlet solution an...

It has been estimated that the world's consumption of Liquefied Natural Gas (LNG) will increase significantly over the next 20 years, thus making exergy recovery from the regasification process a fundamental issue. When LNG is regasified in order to distribute the fuel through a pipeline network, a large amount of exergy is released. Three combined...

This paper explores the consequence of silver nanoparticles morphology (nanowires, nanoplates, and nanospheres) on density, viscosity and thermal conductivity of nanofluids and IoNanoFluids. Nuclear magnetic resonance spectroscopy results reveal that hydroxyl group in cation relates to silver nanoparticle surface of silver IoNanoFluid. Effect on bo...

A new, an efficient and reusable combination of imidazolium based Brønsted acidic ionic liquids (ILs) as a co-catalyst with 5% Ru/C was employed for selective aqueous phase hydrogenation of levulinic acid. Activity and selectivity performance in the hydrogenation of levulinic acid were found to be a function of acidities of ionic liquids. A combina...

In the present paper, we report new data on the vapour pressure of ammonia with 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate [EtOHmim][BF4], 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EtOHmim]-[Tf2N], choline bis(trifluoromethylsulfonyl)imide [N111(2OH)][Tf2N], and trimethyl-N-propylammonium bis(trifluorom...

Liquefied Natural Gas (LNG) has a high exergetic potential because of its low temperature (around −162 °C), although usually the cold released from LNG regasification is wasted. In this paper, the LNG supply chain and the conventional regasification technologies are reviewed and analyzed to identify the cold recovery opportunities. Also, an overvie...

Typical agro-food value chains are equipped with electric refrigeration systems. In many non-industrialized countries, the cold chain is often not guaranteed due to lack of electricity access or unreliable electricity grids. In such cases, refrigeration systems must be equipped with electrical backups or other form of energy storage. This study ana...

Heat exchange systems based on the falling film configuration need a detailed analysis of the design variables and operation of the distributor, which will ensure a homogeneous falling film pattern on a tube bank. The objective of this research was to determine the falling film thickness of the LiBr/H2O at 55wt%, asa function of the convective heat...

This paper discusses the development and implementation of a method based on NIR spectroscopy for the in-situ determination of the ammonia mass fraction of ammonia/water mixtures in an absorber test bench. The calibration model was established using a static measuring system. A cell was designed and constructed to prepare and measure samples at the...

A hydrophobic microporous membrane contactor was proposed and studied as an absorber for an ammonia/water absorption cycle. The heat and mass transfer process in the adiabatic flat sheet membrane module was investigated experimentally and analytically. For the experimental study, a membrane absorber test bench was designed and built. Moreover, a un...

This paper presents and discusses the performance improvement and operational flexibility of a Single-Stage Combined Absorption Power and Refrigeration Cycle (SSAPRC) with an integrated compression booster. The compression booster is placed between the absorber and the evaporator. A mechanical compressor and later a thermal compressor (vapor-ejecto...

Currently, the electrical efficiency of photovoltaic (PV) solar cells ranges between 5–25%. One of the most important parameters that affects the electrical efficiency of a PV collector is the temperature of its cells: the higher temperature, the lower is the efficiency. Photovoltaic/thermal (PV/T) technology is a potential solution to ensure an ac...

The objective of this study is to evaluate the performance of an on-grid PV/T system in a dairy farm located in Osorno (Chile), operated under the Net-Metering scheme. All equipment installed in the farm is driven by electricity and the daily average electric consumption is 235 kWh. The study analyses first the existing installation, second a conve...

An experimental investigation was undertaken to study the actual useful output and performance of a combined power and cooling system that uses low-grade energy. The cycle used was a combination of NH3-H2O absorption refrigeration cycle and Kalina extraction turbine cycle. The expected performance characteristics of the dual output system were firs...

This paper evaluates the experimental performance of two falling-film absorbers with horizontal tubes of a liquid desiccant system. Both absorbers are made of polypropylene in order to avoid corrosion when the LiCl-H2O solution is in contact with them. To improve their wettability, and hence the heat and mass transfer, the tubes from one of the abs...

In this work, experimental tests were executed to analyze the performance of an absorption heat transformer using a quaternary mixture of Lithium salts (LiBr + LiI + LiNO3 + LiCl) with H2O. The high solubility of the quaternary mixture allows the operation of the absorber at a higher salt concentration than with the conventional absorption mixture...

The integration of absorption chillers in micro-cogeneration systems based on micro-gas turbines can be useful as an appropriate strategy to increase the total system energy efficiency. Since it is an area intensive in technology, it is necessary to develop and use models of simulation, which can predict the behavior of the whole system and of each...

An electrolyte solution of Lithium Bromide (LiBr) water was chosen for study because of its wide use in prototype absorption machines. The LiBr must be operated close to the temperature and mass fraction at which lithium bromide achieves the highest efficiency. For the purpose of establishing the concentration in a prototype absorption machines, me...

In this paper ionic liquids are proposed as a novel absorbent for absorption refrigeration application with ammonia as refrigerant. The main objective of this work is to develop a measurement setup to study the absorption capacity of the ammonia vapour in ionic liquids in a pool type absorber. This investigation is essential in order to identify th...

This study presents the first results of composition measurement in an ammonia/water mixture determined at real time using near-infrared (NIR) spectroscopy in an absorber test bench. Two cells were designed and constructed; a static cell for calibrating and a dynamic cell for measuring in the absorber test bench. The ammonia absorption band was not...

Trigeneration plants can use different types of chillers in the same plant, typically single effect and double effect absorption chillers, vapour compression chillers and also cooling storage systems. The highly variable cooling demand of the buildings connected to a district heating and cooling (DHC) network has to be distributed among these chill...

The separation of the air in its components by cryogenic distillation has a high electric consumption due to the required air compression process. This work analyses the energy recovery of the heat dissipated at the intercooling stages of the main compressor by the integration of two types of heat pumps: an Absorption Heat Transformer (AHT) and a V...

The performance of a hybrid liquid desiccant prototype with non-adiabatic air-solution contactors is analyzed in this paper. In order to avoid corrosion all the components that are in direct contact with the liquid desiccant are made of plastic, especially the air-solution contactors that are made of polypropylene. The hybrid liquid desiccant syste...

Solar electrical systems are an efficiency way to reduce the power consumption, therefore, the operational costs of conventional system. In this study, simulation and analysis of an independent solar cooling system are carried out. An air conditioner of the direct expansion type is connected to PV module without using storage batteries. Furthermore...

Present study demonstrates the effect of anions namely Chloride, Bromide, Iodide and tetrafluoroborate on the formation and stabilization of ruthenium nanoparticles in ionic liquid having 1-Butyl-3-methyl imidazolium cation [C4mim]+. UV-visible absorption and IR spectral assignments reflect the role of both cation and anion on stabilization of ruth...

The hydration process of lithium iodide, lithium bromide, lithium chloride and lithium nitrate in water was analyzed quantitatively by applying multivariate curve resolution alternating least squares (MCR-ALS) to their near infrared spectra recorded between 850 nm and 1100 nm. The experiments were carried out using solutions with a salt mass fracti...

The presented work proposes a calculation method to estimate the transient performance of a small on-farm milk cooling system for PV applications. The system employs 3 kg ice for fast cooling of 17 L milk in conventional 20-L-milk-cans. Two units of a commercial DC refrigerator operate at −10 °C and at 4 °C for ice production and milk preservation...

The combination of liquid desiccant systems with conventional vapour compression chillers, usually known as hybrid liquid desiccant systems (HLDS), is a promising alternative when temperature and humidity need to be controlled in air conditioning applications. One of the advantages of this technology is that different kinds of energy can be integra...

- The potential use of solar energy in the food industry has been recognized in several studies, because the processes in this sector require heat moderate temperatures in comparison to others such as chemical, textile and paper industries, and also due to its economic and social relevance. In the dairy industry many studies have been focused on th...

A combined power and cooling cycle can be driven by low grade solar heat to service power and cooling demands in buildings. By operating this cycle to match the building demands, the overall annual performance is improved. In the present study, the annual performance of a solar driven ammonia–water absorption power and cooling system with a biomass...

Mixtures of alkali nitrates in water have good potential to be used as working fluids in absorption refrigeration systems. In this study the extended version of the Brunauer, Emmett, and Teller (BET) model has been used to predict the saturation temperature and vapor pressure of LiNO3–KNO3–NaNO 3/H2O mixtures with two salt ratio values (53:28:19 an...

This paper proposes a methodology based on short-wave near-infrared spectroscopy to determine the ammonia content of ammonia/water mixtures with ammonia mass fraction in the range 0.35-0.65. Establishing this methodology meant modeling the relationship between the pressure bar (15-25) bar, temperature (20-50) °C and composition of the ammonia-water...

A pre-industrial prototype of a new water-cooled ammonia/lithium nitrate absorption chiller was characterised at part-load operation mode. The chiller was built using brazed plate heat exchangers in all its components, including the absorber and the generator.A test campaign was carried out varying the thermal load in the chilled water circuit and...

This article presents several combined absorption cycles proposed for the simultaneous and/or alternative production of power (mechanical or electrical) and refrigeration. The cycles are classified into two groups according to their driving heat source temperature range as low-grade (<200 degrees C (392 degrees F)) and mid-grade (<300 degrees C (57...

A composite of graphene oxide (GO) with mixed oxide (MnCo) was prepared by using a solvothermal method. During the synthesis, both the reduction of GO and growth of metal oxides took place simultaneously. The as-prepared composite material was highly selective for the liquid-phase oxidation of p-cresol to form p-hydroxybenzaldehyde in 71 % yield wi...

Measured values of ultrasonic velocity and density have been used to calculate the isothermal compressibilities (κT) of l-histidine/l-glutamic acid/l-tryptophan/glycylglycine + 2 mol L−1 aqueous KCl/KNO3 systems as a function of amino acid/di-peptide molal concentration and at temperatures in the range of 298.15–323.15 K. The trends of variations o...

Ammonia/lithium nitrate and ammonia/(lithium nitrate + water) have been proposed as suitable working pairs for absorption refrigeration systems driven by low-temperature heat sources. The use of water in the absorbent of the ternary mixture reduces the viscosity of the binary mixture and increases the affinity between the refrigerant (ammonia) and...

1. INTRODUCTION The use of waste heat in modern cogeneration plants achieves increase the energy efficiencies up to 90% or more [1-4]. New technologies and the improvement of existing allow a break in the Brazilian energy system. The economic development that the country had in recent years, and the prospects for future growth make the government,...

Thermodynamic analysis of two stage triple effect absorption cooling and power cycle employing ammonia-water as the working fluid is carried out. Two type of configurations namely type A (power sub-cycle in low temperature stage) and type B (power sub-cycle in high temperature stage) is analyzed. The cycle is simulated for various evaporator, sink...

Air-conditioning demand, especially in hot and humid climates, causes most of the energy consumption in buildings. In these applications, the latent load often constitutes a significant part of the total load. Conventional air-conditioning systems deal with the required dehumidification by cooling the moist air below its dew point and reheat it lat...

Two pre-industrial prototypes of a new ammonia/lithium nitrate absorption chiller, a water-cooled one and an air-cooled one, have been built and experimentally characterized. The single-effect configuration of the absorption refrigeration cycle was selected for both prototypes in which brazed plate heat exchangers were used in all thermal component...

Air conditioning and refrigeration industry can play a significant role in global energy conservation, especially in case of the regions with higher ambient temperature. This industry, currently dominated by electrically driven compression refrigeration systems, has a substantial share in power consumption [1]. Heat driven absorption refrigeration...

This paper proposes a method to characterize the impact of shape on the energy performance of office buildings, considering a wide range of climate types. 16 modular building shapes, from one to 25 stories height, but with the same useful floor area and volume, have been simulated in the 17 climatic zones defined by the ASHRAE Standard. The results...

The main objective of this paper is to simulate different solar absorption power-cooling systems that uses ammonia based working fluid mixture to simultaneously produce cooling and mechanical power with a single system. The power and cooling cycles through absorption are of great interest because they can use low temperature thermal energy sources...

Worldwide, new technologies with higher energy efficiency are needed to replace conventional technologies for either reducing the process costs or energy consumption. For last few years, new working pairs of cations and anions based on ionic liquids and water were studied for green energy technology development to replace the traditional salt solut...

Global environmental concerns and the escalating demand for energy, coupled with steady progress in renewable energy technologies, are opening up new opportunities for utilization of renewable energy resources. Hybrid energy (solar and wind) are the most abundant, inexhaustible and clean of all the renewable energy resources till date. Hybrid power...

A thermodynamic analysis of a two stage absorption cooling and power cycle using ammonia-water as the working fluid is carried out and is compared with that of a single stage cycle. The cycle is simulated for evaporator temperatures between -10°C, and 10°C, absorber and condenser temperatures between 25°C and 45°C. The cooling capacity and power ou...

The thermal stability of three ionic liquids (ILs) with the same anion and different lengths of imadazolium cations was investigated using thermogravimetric analysis to consider their usefulness for their potential application as absorbents in absorption heat pumps and refrigeration cycles. First, the influence of experimental conditions such as sa...

A variable-volume cell was designed, built and validated to measure the solubility of salts in liquid ammonia, using a polythermal method at high pressure. The apparatus is based on a cell made of stainless steel and fitted with a sapphire window to allow the solubility process to be visually controlled. The solubility of three systems was measured...

A modified generator absorber heat exchange (GAX) based absorption heat pump is analyzed in both heating and cooling modes powered by solar energy in this paper. The heat pump designed for a cooling capacity of 10.6 kW utilizes ammonia-water as the working fluid. The effects of the temperatures of absorber, condenser and evaporator on the coefficie...

The association of concentrated solar energy and biomass gasification has often been suggested as an interesting alternative to con-ventional autothermal processes where a significant portion of the biomass has to be used for heat generation to drive endothermic reac-tions. It is a clean process able to produce high quality synthesis gas with a hig...

Combined production of power and cooling can improve energy utilization efficiency significantly. In this paper, a new ammonia/water combined absorption power and cooling cycle is proposed for simultaneous generation of power and cooling. This cycle is a combination of absorption refrigeration and Kalina power cycles. The performance of the cycle w...

Predictive models for the design of falling film condensers and evaporators with water as refrigerant at vacuum operating conditions have been developed in the present work. The models developed in the EES (Engineering Equation Solver) environment will enable us to face the dimensioning and simulation of falling film evaporators and condensers usin...

This work deals with the characterization study of structural and morphological features of Zinc oxide and Titanium dioxide nanoparticles to better understand their role in anomalous properties of nanofluids and ionanofluids. These nanoparticles were purchased from IoLiTec (Ionic Liquids Technologies,Germany) and they have numerous potential applic...

The high energy consumption in buildings in Mediterranean countries, especially in the spring and summer months due to the extensive use of air conditioning, requires immediate actions to minimise energy costs and environmental impact given the current energy crisis. Solar cooling systems offer an attractive solution, but the main drawbacks of this...