Article
Thermodynamics
Ahmad Zarei, Javid Zamani, Liya Hooshyari, Sohrab Zaboli
Summary: The world is facing a cooling crisis, and enhancing the efficiency of cooling systems is the most direct solution to reduce greenhouse gas emissions and costs. This study combined a vapor compression refrigeration cycle and an ejector-ARC to improve system efficiency. The proposed system showed much higher performance than the ARC, with significantly increased COP and ECOP.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Engineering, Chemical
Suset Vazquez-Aveledo, Rosenberg J. Romero, Moises Montiel-Gonzalez, Jesus Cerezo
Summary: Thermal energy recovery systems, including thermal absorption transformers, have the potential to mitigate CO2 emissions. These systems use lithium-water bromide as the working fluid. The Double Stage Heat Transformer (DSHT) is a thermal machine that recovers thermal energy at a higher temperature through the absorption of steam in a concentrated lithium bromide solution. Precise thermodynamic models are used to calculate the operating conditions of the DSHT.
Article
Thermodynamics
A. Huicochea
Summary: The coupling of two absorption heat pumps, one conventional and one unconventional, allows for simultaneous cooling and heating using low-grade heat. This novel advanced absorption heat pump operates with three pressure levels to manipulate the temperature of useful heat. The system achieves cooling temperatures between 14 and 20 degrees C and heating temperatures between 80 and 106 degrees C, utilizing water/lithium bromide as the working solution.
Article
Thermodynamics
Siqi Jing, Qi Chen, Youmiao Zhou, Jianlin Yu
Summary: This paper presents a modified booster-assisted ejector heat pump cycle with dual condensers for heat pump dryer applications. The cycle achieves dual-pressure condensation and improves cycle performance by providing heat duty at two different temperatures. The benefits of the modified cycle are evaluated using thermodynamics and compared with the original cycle. Results show significant improvements in heating coefficient of performance and total exergy destruction with the modified cycle. Additionally, the use of R1234ze(Z) as a refrigerant further enhances the performance of the cycle.
APPLIED THERMAL ENGINEERING
(2023)
Article
Green & Sustainable Science & Technology
Vaclav Novotny, Jan Spale, Jan Pavlicko, David J. Szucs, Michal Kolovratnik
Summary: Absorption cycles can be used for cooling and power generation, benefiting from temperature glide in heat exchangers and utilising low-temperature heat sources. This study presents the world's first absorption power cycle (APC) using a LiBr solution to directly convert low-temperature heat to power. A proof-of-concept system was built and operated with a 360 W design power output, achieving a turbine efficiency of 25% with potential for higher values. The maximal cycle efficiency could be around 5% and utilisation efficiency 0.5%.
Article
Thermodynamics
Pengtao Wang, Hongbin Ma, Jeremy Spitzenberger, Ahmad Abu-Heiba, Kashif Nawaz
Summary: A gas-fired air-to-water ejector heat pump for domestic hot water production was proposed and analyzed thermodynamically in this study. The use of binary fluids and active control of backpressure showed improvements in COP. The first-stage ejector plays a dominant role in system performance, and optimizing various parameters can enhance the EHP performance.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Green & Sustainable Science & Technology
Nazila Nematzadeh, Hadi Ghaebi, Ebrahim Abdi Aghdam
Summary: This paper proposes two novel integrated power cycles for converting low-temperature heat sources to high-temperature sources. A comprehensive simulation is conducted to analyze the energy efficiency, exergy efficiency, and cost of the cycles, as well as the effects of key parameters on their performance.
Article
Thermodynamics
Faustino Correa, Rodrigo Barraza, Yen Chean Soo Too, Ricardo Vasquez Padilla, Jose M. Cardemil
Summary: The study developed a power cycle model to assess the impact of fluctuations on a recompression sCO(2) Brayton cycle during off-design operation, finding that adjusting the recompression fraction according to heat addition and ambient temperature variations leads to superior performance, with up to 70% greater cycle efficiency when the heat addition ratio is reduced to 30%.
Article
Thermodynamics
Anil Kumar, Anish Modi
Summary: This paper proposes two novel configurations of an ejector-assisted compression-absorption-resorption refrigeration system, which includes absorption-resorption and compression sub-cycles. By calculating and comparing the coefficients of performance under different parameters, the results indicate that configuration C2 achieves the highest performance coefficient under specific conditions, and it can save a significant amount of electricity consumption compared to conventional compression refrigeration systems.
Article
Thermodynamics
Jianyong Wang, Zhuan Liu, Haojin Wang, Xiaoqin Liu
Summary: In this paper, a new combined cooling and power system based on the ammonia-water absorption refrigeration cycle is proposed. The system utilizes an ejector to lower the turbine back pressure and improve the net power output. Compared with other systems, the proposed system has a simple structure and good economy.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Su Ruizhi, Yu Zeting, Wang Daohan, Sun Bo, Sun Jia'nan
Summary: A novel power and cooling cogeneration system combining a supercritical CO2 recompression cycle, an ammonia-water absorption refrigeration cycle, and a Kalina cycle has been proposed for efficiently recovering medium-temperature waste heat. A steady-state mathematical model is built to analyze the system's performance. Parametric study reveals significant effects of compressor inlet pressure, SCRC pressure ratio, main compressor and turbine I inlet temperature, and AARC generator pressure on the system's thermodynamic and economic performance.
JOURNAL OF THERMAL SCIENCE
(2022)
Article
Thermodynamics
P. F. Arroiabe, Manex Martinez-Agirre, M. Mounir Bou-Ali
Summary: Various methodologies for determining absorbed vapour mass flux in falling film absorbers have been compared in this study. Three specific criteria were used to evaluate the methods and select the most suitable numerical model for LiBr-H2O absorbers in vertical tube-type falling film absorbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Baomin Dai, Chen Liu, Shengchun Liu, Dabiao Wang, Qilong Wang, Tonghua Zou, Xuan Zhou
Summary: This study proposes three novel transcritical CO2 high-temperature heat pump systems that achieve cascade heat absorption from the heat source through the technique of dual-temperature evaporation with an ejector. The life cycle performances of the new heat pump systems and fuel-fired boilers are comprehensively studied considering energetic, emissions, and economic perspectives. Results show that Ej-Evap2-C has the highest coefficient of performance (COP) and exergy efficiency, and the least pollutant emissions and life cycle cost among different heating methods. The dual-temperature evaporation CO2 high-temperature heat pump is a promising alternative to traditional fuel-fired boilers for generating high-temperature fluid in the future.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Dongpeng Zhao, Weicong Xu, Ruikai Zhao, Shuai Deng, Li Zhao
Summary: Recently, there has been increasing attention towards the combined power and cooling (CPC) cycle due to its higher overall efficiency and diversified energy output. However, there is room for improvement in the existing CPC cycles as they fail to ensure good temperature matching between the cycles and heat sources and sinks simultaneously. This study proposes a novel CPC cycle that integrates various components and meets the requirements for temperature matching under ideal conditions. The performance of the proposed CPC cycle using R600a/R601a mixtures in a geothermal application is analyzed, and the results demonstrate improved exergy efficiency compared to using pure R600a and R601a.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Ramy H. Mohammed, Ali Radwan, Ahmed Rezk, Abdul Ghani Olabi, Vikas Sharma, Abul Kalam Hossain, Abed Alaswad, Mohammad Ali Abdelkareem
Summary: This study computationally investigates an integrated adsorption-absorption system for cooling and desalination, utilizing waste heat. The adsorption cycle successfully utilizes the waste heat from the absorption subsystem, improving energy efficiency. Experimental results show that using a sinusoidal waste heat source enhances water production and cooling effects of the absorption and adsorption subsystems.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Review
Energy & Fuels
Mohamed Amine Zoui, Said Bentouba, John G. Stocholm, Mahmoud Bourouis
Article
Energy & Fuels
Said Bentouba, Mahmoud Bourouis
Summary: The study identified an effective way to use photovoltaic systems in remote arid areas to provide GSM services. Economic research showed that the best configuration included 6 kW photovoltaic panels, 4 kW converter, and 24 storage batteries.
JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Energy & Fuels
Omar Chogueur, Said Bentouba, Mahmoud Bourouis
Summary: The flower pollination algorithm (FPA) is used to improve the controller parameters of a doubly fed induction generator (DFIG), compared with genetic algorithm (GA) and proportional-integral (PI) controllers. Performance analysis of the DFIG is conducted in dynamic mode, showing that applying an optimized PI controller design can enhance the system's performance in the event of electrical disturbances.
JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Energy & Fuels
Maria E. Alvarez, Mahmoud Bourouis
Summary: A theoretical model was developed to study a falling-film absorber on horizontal tubes, showing good agreement with experimental data. Droplet formation and falling-film were found to be important in the absorption process.
Article
Energy & Fuels
Abdelkader Laafer, Djaffar Semmar, Abdelkader Hamid, Mahmoud Bourouis
Summary: This study focused on modeling convective and radiative heat transfer in an energy-efficient house to achieve a stable indoor temperature. The results showed that increasing the temperature of the heat transfer fluid in the floor heating system can stabilize the indoor air temperature, while surface radiosity gradually increased and reached a nearly constant value over time.
Review
Thermodynamics
Carlos Amaris, Mahmoud Bourouis
Summary: Absorption technology is an attractive option for cooling or heating when driven by solar thermal energy, residual heat, or geothermal energy, offering a more environmentally friendly alternative to mechanical compression systems. Desorbers, key components of absorption heat pump technologies, have seen advancements in design concepts to enhance heat and mass transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Said Bentouba, Mahmoud Bourouis, Nadjet Zioui, Arumugam Pirashanthan, Dhayalan Velauthapillai
Summary: The study evaluated the suitability of two commercial simulators, HOMER Pro and RETScreen Expert, for predicting the performance of a large-scale photovoltaic power plant in a hot climate. The results showed deviations in predicted versus actual performance, with temperature having a strong impact on power plant output. It was noted that future photovoltaic power plant designs for hot climates should take into consideration the influence of temperature on output.
Article
Thermodynamics
Adama Coulibaly, Nadjet Zioui, Said Bentouba, Sousso Kelouwani, Mahmoud Bourouis
Summary: Research demonstrates that using thermoelectric generators in vehicle braking can improve energy efficiency. Although only 0.3% of total thermal energy can be converted into electrical energy, it is enough to power on-board instrumentation and vehicle devices.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Andres Rodriguez-Toscano, Carlos Amaris, Alexis Sagastume-Gutierrez, Mahmoud Bourouis
Summary: This study discusses the feasibility of using absorption chillers driven by solar energy and/or natural gas in shopping malls in the Caribbean region of Colombia. The results show that absorption chillers can significantly reduce gas emissions and have good economic benefits.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Mohamed Amine Zoui, Said Bentouba, Dhayalan Velauthapillai, Nadjet Zioui, Mahmoud Bourouis
Summary: The aim of this study is to develop a compact and robust finned tubular thermoelectric generator that can be easily integrated into gas/liquid thermoelectric energy recovery systems. By utilizing a numerical model, the optimal heat exchanger performance was determined. In practical tests, the module successfully generated electricity from hot water.
Article
Energy & Fuels
Omar Ketfi, Hamid Abdi, Billel Lounici, Mahmoud Bourouis
Summary: This study investigates the use of a geothermal heat-sink for removing heat from single and double-effect water-LiBr absorption chillers in hot climates. The results show that both absorption chillers can operate steadily with the implementation of an underground heat-exchanger, providing cooling at inlet temperatures of 33 degrees C. The maximum coefficient of performance achieved is 0.76 and 1.25 for single- and double-effect absorption cycles, respectively, with chilled water at 7 degrees C. The required length of the underground-tube ranges from 4.5 to 18 m, depending on the system configuration and chilled water temperature.
Article
Thermodynamics
Paul Davila, Mahmoud Bourouis, Juan Francisco Nicolalde, Javier Martinez-Gomez
Summary: In this study, a compress-resorption heat pump cycle with a novel CO2/acetone mixture as the working fluid is proposed, aiming to utilize low-grade residual heat in an eco-friendly way. The modeling of the vapor-liquid equilibrium of the mixture and the mass and energy balance of the cycle were conducted using the Peng-Robinson equation and Engineering Equation Solver software. The results showed that the model has a correlation with the literature and the proposed CO2/acetone mixture has a high coefficient of performance.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Djamel Belatrache, Said Bentouba, Nadjet Zioui, Mahmoud Bourouis
Summary: This study examines the potential use of waste material from date palm trees as thermal insulation for buildings in arid climates. Experimental tests determined the thermal conductivity of bricks containing recycled date palm fiber (DPF) and date palm spikelet (DPS), with the sample containing 1.36% DPS demonstrating the best insulation properties. The research showed that buildings constructed with DPS and DPF materials significantly reduced cooling electricity consumption during summer months compared to those built with sand and clay. It was also found that the majority of thermal energy enters rooms through the roofs, with DPF proving to be the most effective thermal insulator.
Article
Thermodynamics
Mandi Mokrane, Mourad Lounis, Mohamed Announ, Maamar Ouali, Med Ali Djebiret, Mahmoud Bourouis
Summary: The study investigated the application of single-phase liquid cooling systems for heat dissipation, showcasing the heat dissipation capability of a micro-heat exchanger. The results demonstrated that under specified temperature and power conditions, the cooling system could effectively lower the temperature of electronic components.
JOURNAL OF THERMAL ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Housam Binous, Ahmed Bellagi
Summary: Liquid-liquid extraction is an important separation technique in chemical engineering, and predicting LLE data accurately is crucial for process design. This paper introduces a new methodology based on arc-length continuation numerical technique to compute LLE data efficiently. The proposed approach demonstrates high reliability and efficiency in predicting LLE data for various ternary systems.
ENGINEERING REPORTS
(2021)
Review
Thermodynamics
Shuling Guo, Ankuo Zhang
Summary: Low-temperature biopreservation is commonly used for medication storage to prolong their shelf life. However, cryo-injury can occur during cryopreservation, making it crucial to find a way to achieve long-term biopreservation without causing harm. The optimal storage temperature for different biomaterials should be investigated to improve storage efficiency. This review discusses the mechanisms of cryo-injury and biopreservation, as well as the reasons for storing biological tissues at various temperature zones. It provides valuable insights for the development of biostorage technology.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
M. Mohsin Tanveer, Craig R. Bradshaw, Joe Orosz, Greg Kemp
Summary: This study investigates the optimal geometric parameters for a spool compressor using simulation models, and the results indicate that a eccentricity ratio of 0.75 and L/D ratios between 1-1.5 can maximize the volumetric and isentropic efficiencies.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Kongkuai Ying, Zhenhua Jiang, Wenting Wu, Jinjian Chu, Shaoshuai Liu, Yinong Wu
Summary: The Stirling/pulse tube cryocooler (SPC) is a highly efficient and long-lasting cryocooler for space applications. It has the ability to adjust the inter-stage refrigeration capacity dynamically by controlling the Stirling displacer in the first stage. This paper proposes an SPC with a second-stage active phase shifter (APS) that can control the phase difference at the second-stage hot end in real time. The experimental results show that the SPC with the APS can provide refrigeration capacity at different temperatures, with a minimum temperature of 13.5K.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Ligeng Li, Hua Tian, Kai Liu, Yibo Wu, Xuan Wang, Xingyu Liang, Gequn Shu
Summary: This study focuses on improving the performance of carbon dioxide refrigeration systems by introducing a multi-ejector design with three controllable ejectors. Experimental analysis shows that the system's performance can be significantly improved by adopting an optimum pressure control strategy under different operating conditions.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Joseph Al Khoury, Rabih Al Haddad, Ghiwa Shakrina, Christelle Bou Malham, Haytham Sayah, Chakib Bouallou, Maroun Nemer
Summary: This study investigates two implementation methods for calculating refrigerant thermodynamic properties and compares their performance. The results show that the implicit fitting method significantly speeds up simulation time and offers greater flexibility for modeling complex energy systems.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Mariella Mateo-Villanueva, Rodolfo Echarri
Summary: This article details three models of different complexity levels for predicting the cold production of a solar cooling device and compares their advantages and disadvantages. The results show that the transient model underestimates the cold generation, while the equilibrium model and universal model overestimate it. The transient model is a useful tool for analyzing the impact of different variables in a solar adsorption refrigeration system, while the simpler models can be used for preliminary design and feasibility studies.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
Article
Thermodynamics
Amin M. Elsafi, Majid Bahrami
Summary: The novel spherical micro-absorbers offer high sorption capacity and surface-to-volume ratios, solving issues such as solution carryover and corrosion associated with conventional absorbers.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2024)
