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N. Velázquez-Limón
Centro de Estudios de las Energías Renovables, Instituto de Ingeniería, Universidad Autónoma de Baja California, Mexicali 21280, Mexico

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Journal article
Published: 01 August 2020 in Energies
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In this work, the analysis of a hybrid LiBr/H2O absorption-cooling and flash-desalination system, using solar thermal energy as heat source, is presented. An absorption open-cycle with three pressure levels is used in combination with a single-stage flash-desalination process to use the coolant as product water, resulting in an increase in cooling and desalination efficiency. For the application, a 20-room coastal hotel complex in San Felipe, Baja California, Mexico, is taken as a case study and the sizing of the solar collection and storage system is carried out for the operation of the proposed hybrid system, during the summer operative period. The operational dynamics during the week with the highest ambient temperatures are presented. The dimensioning of the solar collector’s area and the energy storage resulted in a collection area of 620 m2 with 30 m3, respectively, reaching a solar fraction of 69%. The absorption-cooling subprocess showed an increase of 13.88% in the average coefficient of performance (COP) compared to conventional LiBr/H2O absorption systems. Also, considering that the system provides cooling and desalination simultaneously, the average COPG is 1.64, which is 2.27 times higher than the COP of conventional LiBr/H2O single-effect absorption units. During the critical week, the system presented a desalinated water production of 16.94 m3 with an average performance ratio (PR) of 0.83, while the average daily water production was 2406 kg/day; enough to satisfy the daily water requirements of four people in a coastal hotel in Mexico or to cover the basic services of 24 people according to the World Health Organization.

ACS Style

Nicolás Velázquez-Limón; Ricardo López-Zavala; Luis Hernández-Callejo; Jesús A. Aguilar-Jiménez; Sara Ojeda-Benítez; Juan Ríos-Arriola. Study of a Hybrid Solar Absorption-Cooling and Flash-Desalination System. Energies 2020, 13, 3943 .

AMA Style

Nicolás Velázquez-Limón, Ricardo López-Zavala, Luis Hernández-Callejo, Jesús A. Aguilar-Jiménez, Sara Ojeda-Benítez, Juan Ríos-Arriola. Study of a Hybrid Solar Absorption-Cooling and Flash-Desalination System. Energies. 2020; 13 (15):3943.

Chicago/Turabian Style

Nicolás Velázquez-Limón; Ricardo López-Zavala; Luis Hernández-Callejo; Jesús A. Aguilar-Jiménez; Sara Ojeda-Benítez; Juan Ríos-Arriola. 2020. "Study of a Hybrid Solar Absorption-Cooling and Flash-Desalination System." Energies 13, no. 15: 3943.

Journal article
Published: 03 February 2020 in Applied Thermal Engineering
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This paper presents a study to determine the influence of design variable interactions on the performance of a Stirling engine, as well as a new methodology to identify and quantify such influence. An Alpha-type 2 kW Stirling engine was assessed using a second order model where the engine, heater, regenerator and cooler variables were simultaneously analyzed in pairs. The study includes 240 interactions corresponding to the 16 selected design variables. It was observed that the piston stroke and cylinder diameter variables have more significant interactions with the rest of the parameters due to their strong influence over mass flow. The piston crown length does not show significant interactions; however, it reduces individual thermal losses in the expansion zone. The cycle achieves its maximum net power at angles less than 90° due to pressure, heat losses, and the ratio between mass flow rates and swept volume. Finally, this work presents recommendations for the analyzed interactions. The global interactions scheme provides a qualitative and quantitative identification of the variables that affect the system, synthesized into a hierarchy of variables that indicates a critical path for their exploration for system design and optimization purposes.

ACS Style

Saúl Islas; Ricardo Beltran-Chacon; Nicolas Velazquez-Limon; Daniel Leal-Chávez; R. López-Zavala; Jesús Armando Aguilar. A numerical study of the influence of design variable interactions on the performance of a Stirling engine System. Applied Thermal Engineering 2020, 170, 115039 .

AMA Style

Saúl Islas, Ricardo Beltran-Chacon, Nicolas Velazquez-Limon, Daniel Leal-Chávez, R. López-Zavala, Jesús Armando Aguilar. A numerical study of the influence of design variable interactions on the performance of a Stirling engine System. Applied Thermal Engineering. 2020; 170 ():115039.

Chicago/Turabian Style

Saúl Islas; Ricardo Beltran-Chacon; Nicolas Velazquez-Limon; Daniel Leal-Chávez; R. López-Zavala; Jesús Armando Aguilar. 2020. "A numerical study of the influence of design variable interactions on the performance of a Stirling engine System." Applied Thermal Engineering 170, no. : 115039.

Conference paper
Published: 05 January 2020 in Communications in Computer and Information Science
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In this work, we present the study of seawater desalination potential using the energy surpluses of a microgrid based on renewable energies and a thermosolar absorption cooling system, installed in the isolated community of Puertecitos, Mexico and its primary school, respectively. Given the profile of electricity demand of the community in winter and the non-need for air conditioning, both systems can be used for the desalination of seawater, a resource greatly needed in the region because of the scarcity that is presented. Using the software TRNSYS and Aspen Plus, the simulation of the generating systems was carried out, activating a multiple-effect seawater desalination system during a typical week of February with measured data of electrical consumption. The results show that, with the energy available from both systems, it is possible to desalinate 2,500 kg/day of water with a thermal consumption of 25 kW, during 6 h daily operation. The electrical energy supplied by the microgrid contributes four times more to the desalination of water than the thermal solar field. With this production, it is possible to satisfy the basic requirements of hygiene, hydration and food for 25 people.

ACS Style

Jesús Armando Aguilar-Jiménez; Nicolas Velazquez-Limon; Ricardo Beltrán; Luis Hernández-Callejo; Ricardo López-Zavala; Edgar González-San Pedro. Potential for Thermal Water Desalination Using Microgrid and Solar Thermal Field Energy Surpluses in an Isolated Community. Communications in Computer and Information Science 2020, 162 -175.

AMA Style

Jesús Armando Aguilar-Jiménez, Nicolas Velazquez-Limon, Ricardo Beltrán, Luis Hernández-Callejo, Ricardo López-Zavala, Edgar González-San Pedro. Potential for Thermal Water Desalination Using Microgrid and Solar Thermal Field Energy Surpluses in an Isolated Community. Communications in Computer and Information Science. 2020; ():162-175.

Chicago/Turabian Style

Jesús Armando Aguilar-Jiménez; Nicolas Velazquez-Limon; Ricardo Beltrán; Luis Hernández-Callejo; Ricardo López-Zavala; Edgar González-San Pedro. 2020. "Potential for Thermal Water Desalination Using Microgrid and Solar Thermal Field Energy Surpluses in an Isolated Community." Communications in Computer and Information Science , no. : 162-175.

Journal article
Published: 13 December 2019 in Desalination
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This paper presents a novel energetic integration of a Multiple Effect Thermal Desalination System (MED) and an Organic Rankine Cycle (ORC) for simultaneous production of potable water and electrical energy, using low-temperature energetic sources. The thermal energy required for the system's operation is supplied by the MED's evaporator, while the ORC is activated using a fraction of the latent heat of condensation of the water vapor produced in the first effect of the MED. By doing this, the production of water in the first stage of the desalination system increases and, thus, the final production of distillate also increases. A simulation and validation of the proposal was conducted. The MED/ORC system has a 3.95% increase on the average Performance Ratio when the electrical energy production increases in 10 kW, presenting only a 1.57% increase on the total heat transfer area. MED/ORC system with an electrical energy production of 50 kW is 22% more efficient in water desalination than a MED system without integration, while requiring only 6.9% more heat transfer area. The results show that the MED/ORC energetic integration studied benefits both the final production of desalinized water, and the MED's efficiency without considerably increasing the required heat transfer area.

ACS Style

J.A. Aguilar-Jiménez; Nicolas Velazquez-Limon; R. López-Zavala; R. Beltrán; Luis Hernández Callejo; L.A. González-Uribe; V. Alonso-Gómez. Low-temperature multiple-effect desalination/organic Rankine cycle system with a novel integration for fresh water and electrical energy production. Desalination 2019, 477, 114269 .

AMA Style

J.A. Aguilar-Jiménez, Nicolas Velazquez-Limon, R. López-Zavala, R. Beltrán, Luis Hernández Callejo, L.A. González-Uribe, V. Alonso-Gómez. Low-temperature multiple-effect desalination/organic Rankine cycle system with a novel integration for fresh water and electrical energy production. Desalination. 2019; 477 ():114269.

Chicago/Turabian Style

J.A. Aguilar-Jiménez; Nicolas Velazquez-Limon; R. López-Zavala; R. Beltrán; Luis Hernández Callejo; L.A. González-Uribe; V. Alonso-Gómez. 2019. "Low-temperature multiple-effect desalination/organic Rankine cycle system with a novel integration for fresh water and electrical energy production." Desalination 477, no. : 114269.

Journal article
Published: 12 December 2019 in International Journal of Refrigeration
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In this work, we present the simulation study of a LiBr-H2O solar thermal absorption air conditioning system, installed in an isolated primary school in the community of Puertecitos, Mexico. The collection system consists of 110 m2 of evacuated tube solar collectors that produce the thermal energy needed to activate the chiller, while four cooling coils of 8.75 kW each cool the classrooms of the school with the chilled water produced. The characteristics of the system's equipment are used and a simulator is developed to determine the optimum operational strategies, given the conditions to which it will be subjected before the start-up of the plant. This is intended to ensure the comfort conditions of the students within the classrooms during the weekly class periods. The results show that the installed system is capable of satisfying the cooling needs of the school with the simulated strategies, but for a stable operation, periods of time must be dedicated for the recovery of energy inside the thermal storage tank. Some experiences are mentioned, both of the start-up and economic, related to an installation in an isolated community. The cost of the balance of plant was the highest with 36% of the total project, followed by the chiller and the solar field with 25 and 18%, respectively. The preliminary experimental results obtained during the implementation of the system are presented, where some of the operational strategies resulting from the simulation study can be confirmed.

ACS Style

J.A. Aguilar-Jiménez; Nicolas Velazquez-Limon; R. López-Zavala; L.A. González-Uribe; S. Islas; E. González; L. Ramírez; R. Beltrán. Optimum operational strategies for a solar absorption cooling system in an isolated school of Mexico. International Journal of Refrigeration 2019, 112, 1 -13.

AMA Style

J.A. Aguilar-Jiménez, Nicolas Velazquez-Limon, R. López-Zavala, L.A. González-Uribe, S. Islas, E. González, L. Ramírez, R. Beltrán. Optimum operational strategies for a solar absorption cooling system in an isolated school of Mexico. International Journal of Refrigeration. 2019; 112 ():1-13.

Chicago/Turabian Style

J.A. Aguilar-Jiménez; Nicolas Velazquez-Limon; R. López-Zavala; L.A. González-Uribe; S. Islas; E. González; L. Ramírez; R. Beltrán. 2019. "Optimum operational strategies for a solar absorption cooling system in an isolated school of Mexico." International Journal of Refrigeration 112, no. : 1-13.

Journal article
Published: 19 September 2019 in Entropy
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This paper proposes the configuration of an Organic Rankine Cycle (ORC) coupled to a solar domestic hot water system (SDHWS) with the purpose of analyzing the cogeneration capacity of the system. A simulation of the SDHWS was conducted at different temperatures, observing its performance to determine the amounts of useable heat generated by the solar collector; thus, from an energy balance point of view, the amount of heat that may be used by the ORC could be determined. The working fluid that would be suitable for the temperatures and pressures in the system was selected. The best fluid for the given conditions of superheated vapor at 120 °C and 604 kPa and a condensation temperature of 60 °C and 115 kPa was acetone. The main parameters for the expander thermodynamic design that may be used by the ORC were obtained, with the possibility of generating 443 kWh of annual electric energy with 6.65% global efficiency of solar to electric power, or an overall efficiency of the cogeneration system of 56.35% with a solar collector of 2.84 m2.

ACS Style

Daniel Leal-Chavez; Ricardo Beltran-Chacon; Paola Cardenas-Terrazas; Saúl Islas; Nicolas Velazquez-Limon. Design and Analysis of the Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System. Entropy 2019, 21, 911 .

AMA Style

Daniel Leal-Chavez, Ricardo Beltran-Chacon, Paola Cardenas-Terrazas, Saúl Islas, Nicolas Velazquez-Limon. Design and Analysis of the Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System. Entropy. 2019; 21 (9):911.

Chicago/Turabian Style

Daniel Leal-Chavez; Ricardo Beltran-Chacon; Paola Cardenas-Terrazas; Saúl Islas; Nicolas Velazquez-Limon. 2019. "Design and Analysis of the Domestic Micro-Cogeneration Potential for an ORC System Adapted to a Solar Domestic Hot Water System." Entropy 21, no. 9: 911.

Journal article
Published: 12 September 2019 in Desalination
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This paper presents a novel cooling and desalination system that uses seawater as coolant, and that has a high energetic and internal mass integration, as well as higher capacity and efficiency levels. The proposed system was simulated using Aspen Plus software; its operative behavior was also evaluated in order to prove its technical feasibility. Using a 23 kW simple-effect absorption cooling machine as a basis, and utilizing the produce of desalination as coolant, this technological approach increases the system's capacity by a factor of 87.4, to 2012 kW. It also increases the COP value to 6.15, 8.54 times greater than the 0.72 COP reported for this type of systems. Furthermore, the system produces 73,569 L/day of water, with an RR of 0.56 and a PR of 6.63. The proposed technology presents a setup that allows for a high energetic and internal mass integration, which increases the system's capacity and efficiency.

ACS Style

R. López-Zavala; N. Velázquez; L.A. González-Uribe; K.M. Quezada-Espinoza; Jesús Armando Aguilar; S. Islas; M. Nakasima-López; E. González. Absorption cooling and desalination system with a novel internal energetic and mass integration that increases capacity and efficiency. Desalination 2019, 471, 114144 .

AMA Style

R. López-Zavala, N. Velázquez, L.A. González-Uribe, K.M. Quezada-Espinoza, Jesús Armando Aguilar, S. Islas, M. Nakasima-López, E. González. Absorption cooling and desalination system with a novel internal energetic and mass integration that increases capacity and efficiency. Desalination. 2019; 471 ():114144.

Chicago/Turabian Style

R. López-Zavala; N. Velázquez; L.A. González-Uribe; K.M. Quezada-Espinoza; Jesús Armando Aguilar; S. Islas; M. Nakasima-López; E. González. 2019. "Absorption cooling and desalination system with a novel internal energetic and mass integration that increases capacity and efficiency." Desalination 471, no. : 114144.

Journal article
Published: 18 August 2019 in Applied Sciences
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In this work, we present an absorption cooling system with 35 kW capacity driven by solar thermal energy, installed in the school of Puertecitos, Mexico, an off-grid community with a high level of social marginalization. The cooling system provides thermal comfort to the school’s classrooms through four 8.75-kW cooling coils, while a 110-m2 field of evacuated tube solar collectors delivers the thermal energy needed to activate the cooling machine. The characteristics of the equipment installed in the school were used for simulation and operative analysis of the system under the influence of typical factors of an isolated coastal community, such as the influence of climate, thermal load, and water consumption in the cooling tower, among others. The aim of this simulation study was to determine the best operating conditions prior to system start-up, to establish the requirements for external heating and cooling services, and to quantify the freshwater requirements for the proper functioning of the system. The results show that, with the simulated strategies implemented, with a maximum load operation, the system can maintain thermal comfort in the classrooms for five days of classes. This is feasible as long as weekends are dedicated to raising the water temperature in the thermal storage tank. As the total capacity of the system is distributed in the four cooling coils, it is possible to control the cooling demand in order to extend the operation periods. Utilizing 75% or less of the cooling capacity, the system can operate continuously, taking advantage of stored energy. The cooling tower requires about 750 kg of water per day, which becomes critical given the scarcity of this resource in the community.

ACS Style

Jesús Armando Aguilar-Jiménez; Nicolás Velázquez; Ricardo López-Zavala; Luis A. González-Uribe; Ricardo Beltrán; Luis Hernández-Callejo. Simulation of a Solar-Assisted Air-Conditioning System Applied to a Remote School. Applied Sciences 2019, 9, 3398 .

AMA Style

Jesús Armando Aguilar-Jiménez, Nicolás Velázquez, Ricardo López-Zavala, Luis A. González-Uribe, Ricardo Beltrán, Luis Hernández-Callejo. Simulation of a Solar-Assisted Air-Conditioning System Applied to a Remote School. Applied Sciences. 2019; 9 (16):3398.

Chicago/Turabian Style

Jesús Armando Aguilar-Jiménez; Nicolás Velázquez; Ricardo López-Zavala; Luis A. González-Uribe; Ricardo Beltrán; Luis Hernández-Callejo. 2019. "Simulation of a Solar-Assisted Air-Conditioning System Applied to a Remote School." Applied Sciences 9, no. 16: 3398.

Journal article
Published: 05 January 2019 in International Journal of Refrigeration
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This paper presents a novel LiBr/H2O absorption cooling and desalination system with three pressure levels which uses seawater as a cooling medium and is activated by solar thermal energy. This system helps counteract coastal populations’ thermal conditioning and water supply problems. In order to show technical feasibility, Aspen Plus was used to simulate the system with the following parameters: a 23 kW cooling capacity; different seawater temperatures; and, a concentration of 35,000 ppm. It was found that the proposed technology has 19.4% more efficiency than a conventional single-effect absorption cooling system, with an FR of 0.08 and an R of 1.84, and produces 838 additional L/day of water, enough to satisfy the requirements of a household for up to 7 people. With the configuration of the proposed technology, which manages three levels of pressure, and using seawater as a cooling medium, the simultaneous production of cooling and desalination is benefited.

ACS Style

R. López-Zavala; N. Velázquez-Limón; L.A. González-Uribe; J.A. Aguilar-Jiménez; J. Alvarez-Mancilla; A. Acuña; S. Islas. A novel LiBr/H2O absorption cooling and desalination system with three pressure levels. International Journal of Refrigeration 2019, 99, 469 -478.

AMA Style

R. López-Zavala, N. Velázquez-Limón, L.A. González-Uribe, J.A. Aguilar-Jiménez, J. Alvarez-Mancilla, A. Acuña, S. Islas. A novel LiBr/H2O absorption cooling and desalination system with three pressure levels. International Journal of Refrigeration. 2019; 99 ():469-478.

Chicago/Turabian Style

R. López-Zavala; N. Velázquez-Limón; L.A. González-Uribe; J.A. Aguilar-Jiménez; J. Alvarez-Mancilla; A. Acuña; S. Islas. 2019. "A novel LiBr/H2O absorption cooling and desalination system with three pressure levels." International Journal of Refrigeration 99, no. : 469-478.

Journal article
Published: 05 September 2018 in Solar Energy
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In this work an economic and technical analysis on a hybrid Photovoltaic (PV) – Concentrated solar power (CSP) system, to be used as an energy source in isolated microgrids, is conducted using the microgrid in Puertecitos, Baja California, Mexico as a case study. The PV-CSP system uses a field of solar concentrators with thermal storage to activate a 30 kW organic Rankine cycle, which satisfies the community's energy demand during periods of low or no solar radiation. The PV field provides 73 kW to cover the electrical needs of the community during the daytime, the period in which the CSP field stores sensible heat in tanks for later use. An operational and economic study that compares the hybrid system to the one currently used in the microgrid is presented. The results show that, for the case study, the levelized cost of energy (LCOE) for the PV-CSP hybrid system is 0.524 USD/kWh, only 2% higher than the LCOE for the PV-Battery, 0.51 USD/kWh. However, if the PV-CSP were used in a community with an energy demand 50% larger, the LCOE would be of 0.506 USD/kWh. Furthermore, if the community’s demand exceeds 500 kW, the LCOE of the PV-CSP would be 26% lower. If the system is harnessed to its maximum capacity throughout the year, its LCOE can be comparable to, and as competitive as that of large commercial hybrid plants. The hybridization of these systems allows a manageability and complementarity of energy that, when applied to isolated microgrids, diminishes or eliminates the problem of battery storage, resulting in costs reduction during the useful life of the project.

ACS Style

Jesús Armando Aguilar; Nicolas Velazquez-Limon; A. Acuña; R. Cota; Luis Antonio Gonzalez-Uribe; Ricardo López-Zavala; S. Islas. Techno-economic analysis of a hybrid PV-CSP system with thermal energy storage applied to isolated microgrids. Solar Energy 2018, 174, 55 -65.

AMA Style

Jesús Armando Aguilar, Nicolas Velazquez-Limon, A. Acuña, R. Cota, Luis Antonio Gonzalez-Uribe, Ricardo López-Zavala, S. Islas. Techno-economic analysis of a hybrid PV-CSP system with thermal energy storage applied to isolated microgrids. Solar Energy. 2018; 174 ():55-65.

Chicago/Turabian Style

Jesús Armando Aguilar; Nicolas Velazquez-Limon; A. Acuña; R. Cota; Luis Antonio Gonzalez-Uribe; Ricardo López-Zavala; S. Islas. 2018. "Techno-economic analysis of a hybrid PV-CSP system with thermal energy storage applied to isolated microgrids." Solar Energy 174, no. : 55-65.

Journal article
Published: 01 February 2018 in Applied Thermal Engineering
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Jesús Armando Aguilar; Nicolas Velazquez-Limon; A. Acuña; Ricardo López-Zavala; Luis Antonio Gonzalez-Uribe. Effect of orientation of a CPC with concentric tube on efficiency. Applied Thermal Engineering 2018, 130, 221 -229.

AMA Style

Jesús Armando Aguilar, Nicolas Velazquez-Limon, A. Acuña, Ricardo López-Zavala, Luis Antonio Gonzalez-Uribe. Effect of orientation of a CPC with concentric tube on efficiency. Applied Thermal Engineering. 2018; 130 ():221-229.

Chicago/Turabian Style

Jesús Armando Aguilar; Nicolas Velazquez-Limon; A. Acuña; Ricardo López-Zavala; Luis Antonio Gonzalez-Uribe. 2018. "Effect of orientation of a CPC with concentric tube on efficiency." Applied Thermal Engineering 130, no. : 221-229.

Journal article
Published: 29 July 2017 in Sensors
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Solar collector technologies operate with better performance when the Sun beam direction is normal to the capturing surface, and for that to happen despite the relative movement of the Sun, solar tracking systems are used, therefore, there are rules and standards that need minimum accuracy for these tracking systems to be used in solar collectors’ evaluation. Obtaining accuracy is not an easy job, hence in this document the design, construction and characterization of a sensor based on a visual system that finds the relative azimuth error and height of the solar surface of interest, is presented. With these characteristics, the sensor can be used as a reference in control systems and their evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial measurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the sunrays’ direction as well as the tilt and sensor position. The sensor’s characterization proved how a measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426° and an uncertainty of 0.986%, which can be modified to reach an accuracy under 0.01°. The validation of this sensor was determined showing the focus error on one of the best commercial solar tracking systems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system meets the Sun detection requirements and components that meet the accuracy conditions to be used in solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic installations and solar collectors.

ACS Style

Adolfo Ruelas; Nicolás Velázquez; Carlos Villa-Angulo; Alexis Acuña; Pedro Rosales; José Suastegui. A Solar Position Sensor Based on Image Vision. Sensors 2017, 17, 1742 .

AMA Style

Adolfo Ruelas, Nicolás Velázquez, Carlos Villa-Angulo, Alexis Acuña, Pedro Rosales, José Suastegui. A Solar Position Sensor Based on Image Vision. Sensors. 2017; 17 (8):1742.

Chicago/Turabian Style

Adolfo Ruelas; Nicolás Velázquez; Carlos Villa-Angulo; Alexis Acuña; Pedro Rosales; José Suastegui. 2017. "A Solar Position Sensor Based on Image Vision." Sensors 17, no. 8: 1742.

Journal article
Published: 01 June 2017 in Journal of Energy Engineering
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Compound parabolic concentrators (CPCs) are technologies that allow heat exchange between solar radiation and a fluid. Incorporation of a concentric tube receiver has been proposed as a means of improving the performance of CPCs. Such geometry has been used to improve the processes of heat transfer in refrigeration tubes. Here, the authors report mathematical modeling, simulation, design, and construction of four CPCs with concentric tube receivers, as well as experimental study. The study begins with the proposal of a mathematical model based on heat transfer equations, as reported in the literature. Subsequently, the authors designed and built a test bank consisting of four CPCs. The test bank can be operated with the four CPCs, working as either a serial or parallel flow. Based on experimental results, it was possible to obtain the characteristic curves of the solar collector operating in both modes. After validating the mathematical model with the experimental results, a correlation to adjust the simulator removal factor of the CPCs with concentric tubes was added. This setting improved the simulator results by 68%. Once validated, the simulator was used to compare the performance of a concentric tube and a simple receiver tube. The results show that the concentric receiver tube outperforms the simple receiver tube.

ACS Style

A. Acuña; N. Velázquez; D. Sauceda; Jesús Armando Aguilar. Modeling, Construction, and Experimentation of a Compound Parabolic Concentrator with a Concentric Tube as the Absorber. Journal of Energy Engineering 2017, 143, 04016059 .

AMA Style

A. Acuña, N. Velázquez, D. Sauceda, Jesús Armando Aguilar. Modeling, Construction, and Experimentation of a Compound Parabolic Concentrator with a Concentric Tube as the Absorber. Journal of Energy Engineering. 2017; 143 (3):04016059.

Chicago/Turabian Style

A. Acuña; N. Velázquez; D. Sauceda; Jesús Armando Aguilar. 2017. "Modeling, Construction, and Experimentation of a Compound Parabolic Concentrator with a Concentric Tube as the Absorber." Journal of Energy Engineering 143, no. 3: 04016059.

Journal article
Published: 17 April 2017 in IEEE Power and Energy Magazine
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Increasing power system resilience at the distribution level is crucial due to the negative social impact of blackouts, as the undesired consequences get worse the longer the system restoration takes. Statistical records demonstrate that system recovery times after high-impact, low-probability events (e.g., earthquakes, tsunamis, and floods) are often faster for generation and transmission segments than for the distribution system. During the 2010 Chilean earthquake (8.8 Mw on the Richter scale), for example, the distribution system in the most affected area (almost 1.1 million customers) was not totally back in service until two weeks after the first major seismic event. In contrast, the transmission system rapidly recovered, with most of the bulk system buses re-energized by the end of the first day and the remainder during the second day. Additional installed generation capacity and repairing minor damage to most of the affected generation plants allowed for the recovery of most of the supply within a few days. Only 6.1% of the installed generation capacity required major repairs (which took up to six months to complete).

ACS Style

Guillermo Jimenez-Estevez; Alejandro Navarro-Espinosa; Rodrigo Palma-Behnke; Luigi Lanuzza; Nicolas Velazquez-Limon. Achieving Resilience at Distribution Level: Learning from Isolated Community Microgrids. IEEE Power and Energy Magazine 2017, 15, 64 -73.

AMA Style

Guillermo Jimenez-Estevez, Alejandro Navarro-Espinosa, Rodrigo Palma-Behnke, Luigi Lanuzza, Nicolas Velazquez-Limon. Achieving Resilience at Distribution Level: Learning from Isolated Community Microgrids. IEEE Power and Energy Magazine. 2017; 15 (3):64-73.

Chicago/Turabian Style

Guillermo Jimenez-Estevez; Alejandro Navarro-Espinosa; Rodrigo Palma-Behnke; Luigi Lanuzza; Nicolas Velazquez-Limon. 2017. "Achieving Resilience at Distribution Level: Learning from Isolated Community Microgrids." IEEE Power and Energy Magazine 15, no. 3: 64-73.

Journal article
Published: 01 April 2017 in International Journal of Refrigeration
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ACS Style

A. Acuña; F. Lara; P. Rosales; J. Suastegui; N. Velázquez; A. Ruelas. Impact of a vertical geothermal heat exchanger on the solar fraction of a solar cooling system. International Journal of Refrigeration 2017, 76, 63 -72.

AMA Style

A. Acuña, F. Lara, P. Rosales, J. Suastegui, N. Velázquez, A. Ruelas. Impact of a vertical geothermal heat exchanger on the solar fraction of a solar cooling system. International Journal of Refrigeration. 2017; 76 ():63-72.

Chicago/Turabian Style

A. Acuña; F. Lara; P. Rosales; J. Suastegui; N. Velázquez; A. Ruelas. 2017. "Impact of a vertical geothermal heat exchanger on the solar fraction of a solar cooling system." International Journal of Refrigeration 76, no. : 63-72.

Journal article
Published: 01 January 2017 in Información tecnológica
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ACS Style

Mydory Nakasima-López; Paul Taboada-González; Quetzalli Aguilar-Virgen; Nicolás Velázquez-Limón. Adaptación de Inóculos Durante el Arranque de la Digestión Anaerobia con Residuos Sólidos Orgánicos. Información tecnológica 2017, 28, 199 -208.

AMA Style

Mydory Nakasima-López, Paul Taboada-González, Quetzalli Aguilar-Virgen, Nicolás Velázquez-Limón. Adaptación de Inóculos Durante el Arranque de la Digestión Anaerobia con Residuos Sólidos Orgánicos. Información tecnológica. 2017; 28 (1):199-208.

Chicago/Turabian Style

Mydory Nakasima-López; Paul Taboada-González; Quetzalli Aguilar-Virgen; Nicolás Velázquez-Limón. 2017. "Adaptación de Inóculos Durante el Arranque de la Digestión Anaerobia con Residuos Sólidos Orgánicos." Información tecnológica 28, no. 1: 199-208.

Journal article
Published: 01 January 2017 in Solar Energy
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José Ruelas; Nicolas Velazquez-Limon; Ricardo Beltrán. Opto–geometric performance of fixed-focus solar concentrators. Solar Energy 2017, 141, 303 -310.

AMA Style

José Ruelas, Nicolas Velazquez-Limon, Ricardo Beltrán. Opto–geometric performance of fixed-focus solar concentrators. Solar Energy. 2017; 141 ():303-310.

Chicago/Turabian Style

José Ruelas; Nicolas Velazquez-Limon; Ricardo Beltrán. 2017. "Opto–geometric performance of fixed-focus solar concentrators." Solar Energy 141, no. : 303-310.

Journal article
Published: 07 April 2016 in Applied Thermal Engineering
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This article presents the performance of a diffusion absorption cooling system that uses a solar compound parabolic concentrator (CPC) as the heat source. The cooling system uses lithium nitrate (LiNO3) and sodium thiocyanate (NaSCN) absorbent substances, and ammonia (NH3) as a refrigerant. The heat transfer fluids between the CPC and the cooling system studied were glycerol–water (C3H8O3–H2O), ethylene glycol–water (C2H6O2–H2O) and propylene glycol–water (C3H8O2–H2O). For the study of the solar cooling system, a mathematical model was developed and a simulator validated with experimental results of a properly designed CPC. The effects of the heat transfer fluid concentration and mass flow rate were evaluated against the coefficient of performance (COP). In addition, the work includes assessing the influence of the solar radiation and the ambient temperature on the solar cooling system COP. According to the results, the best options were the NH3–LiNO3 working mixture and the C3H8O3–H2O heat transfer fluid.

ACS Style

A. Acuña; Nicolas Velazquez-Limon; D. Sauceda; P. Rosales; A. Suastegui; Alejandro-Sebastián Ortiz-Pérez. Influence of a compound parabolic concentrator in the performance of a solar diffusion absorption cooling system. Applied Thermal Engineering 2016, 102, 1374 -1383.

AMA Style

A. Acuña, Nicolas Velazquez-Limon, D. Sauceda, P. Rosales, A. Suastegui, Alejandro-Sebastián Ortiz-Pérez. Influence of a compound parabolic concentrator in the performance of a solar diffusion absorption cooling system. Applied Thermal Engineering. 2016; 102 ():1374-1383.

Chicago/Turabian Style

A. Acuña; Nicolas Velazquez-Limon; D. Sauceda; P. Rosales; A. Suastegui; Alejandro-Sebastián Ortiz-Pérez. 2016. "Influence of a compound parabolic concentrator in the performance of a solar diffusion absorption cooling system." Applied Thermal Engineering 102, no. : 1374-1383.

Communication
Published: 23 October 2015 in Atmosphere
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Net radiation is an essential forcing of climate in the lower layers of Earth’s atmosphere. In this paper, radiation balance is measured in clay soil and green grass, and is compared with three urban materials. These materials: asphalt, concrete and white painted elastomeric polystyrene roofing sheet are widely used in Mexicali, Baja California, México. This study was carried out during August of 2011, the hottest time of the year. The 24-hour average values of net radiation found were: 137.2 W·m−2 for asphalt, 119.1 for concrete, 104.6 for clay soil, 152 for green grass and 29.2 for the polystyrene insulation. The latter two types of materials are likely to be the most effective in reducing urban heat island effects. This variation in the radiation balance has widespread implications for human living conditions, as land cover change tends to be towards surfaces that have higher levels of net radiation.

ACS Style

Néstor Santillán-Soto; Rafael García-Cueto; Zalia Haro-Rincón; Sara Ojeda-Benítez; Margarito Quintero-Núñez; Nicolás Velázquez-Limón. Radiation Balance of Urban Materials and Their Thermal Impact in Semi-Desert Region: Mexicali, México Study Case. Atmosphere 2015, 6, 1578 -1589.

AMA Style

Néstor Santillán-Soto, Rafael García-Cueto, Zalia Haro-Rincón, Sara Ojeda-Benítez, Margarito Quintero-Núñez, Nicolás Velázquez-Limón. Radiation Balance of Urban Materials and Their Thermal Impact in Semi-Desert Region: Mexicali, México Study Case. Atmosphere. 2015; 6 (10):1578-1589.

Chicago/Turabian Style

Néstor Santillán-Soto; Rafael García-Cueto; Zalia Haro-Rincón; Sara Ojeda-Benítez; Margarito Quintero-Núñez; Nicolás Velázquez-Limón. 2015. "Radiation Balance of Urban Materials and Their Thermal Impact in Semi-Desert Region: Mexicali, México Study Case." Atmosphere 6, no. 10: 1578-1589.

Journal article
Published: 01 September 2014 in International Journal of Refrigeration
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Alexis Acuna; F. Lara; Nicolas Velazquez-Limon; Jesus Cerezo. Optimum generator temperature to couple different diffusion absorption solar cooling systems. International Journal of Refrigeration 2014, 45, 128 -135.

AMA Style

Alexis Acuna, F. Lara, Nicolas Velazquez-Limon, Jesus Cerezo. Optimum generator temperature to couple different diffusion absorption solar cooling systems. International Journal of Refrigeration. 2014; 45 ():128-135.

Chicago/Turabian Style

Alexis Acuna; F. Lara; Nicolas Velazquez-Limon; Jesus Cerezo. 2014. "Optimum generator temperature to couple different diffusion absorption solar cooling systems." International Journal of Refrigeration 45, no. : 128-135.