Modelling and Simulation of a Solar Single Effect Absorption Cooling System in Aspen Hysys®

2016 ◽  
Author(s):  
Erni S. Ramos ◽  
Guillermo E. Valencia ◽  
Adriana M. Jiménez ◽  
Marisol Osorio ◽  
Marley C. Vanegas
Keyword(s):  
Loss Rate ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Second Law ◽  
Total Solar Radiation ◽  
Steady State Condition ◽  
Aspen Hysys ◽  
Absorption Cooling ◽  
Single Effect

As an alternative to conventional vapor compression cooling systems, a thermodynamic analysis with the integration of Aspen Hysys® and MatLab® to a solar driven single effect LiBr - Water absorption cooling is conducted in this paper under meteorological conditions for Barranquilla in Colombia supplied with a solar captive system integrated by 15 flat plat solar collectors Barilla F22AR. First law and second law of thermodynamic are applied to system in order to calculate the thermodynamic states and exergy of each stream of the system, in addition to the Coefficient of performance and second law exergy efficiency of the chiller, and exergy loss rate for every component and the whole system. The influence of monthly variation of total solar irradiance on COP, exergy efficiency and exergy loss rate is evaluated in this study under steady state condition for each month of the year. The results of this study show a proportional relationship between heat loads calculated in each component and the heat flow supplied by the solar captive system to the generator, moreover the total solar radiation is directly related to the COP and inversely proportional exergy efficiency.

scholarly journals Exergy Analyses of Onion Drying by Convection: Influence of Dryer Parameters on Its Performance

2018 ◽  
Author(s):  
María Castro ◽  
Celia Román ◽  
Marcelo Echegaray ◽  
Germán Mazza ◽  
Rosa Rodriguez
Keyword(s):  
Flow Rate ◽  
Loss Rate ◽  
Air Flow ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Air Flow Rate ◽  
Sustainability Index ◽  
Improvement Potential ◽  
Drying Chamber ◽  
Potential Rate

This research work is concerned in the exergy analysis of the continuous-convection drying of onion. The influence of temperature and air flow rate was studied in terms of exergy parameters. The energy and exergy balances were carried out taking into account the onion drying chamber. Its behaviour was analysed based on exergy efficiency, exergy loss rate, exergetic improvement potential rate and sustainability index. The exergy loss rates increase with the temperature and air flow rate augmentation. Exergy loss rate is augmented at higher drying air temperatures and flow rates because the overall heat transfer coefficient increase. On the other hand, the exergy efficiency increases with the air flow rate augmentation. This behavior is due to the energy utilization was improved because the most amount of supplied energy was utilized for the moisture evaporation. However, the exergy efficiency decreases with the temperature augmentation due to the free moisture is less, then, the moisture begins diffusing from the internal structure to the surface. The exergetic improvement potential rate values show that the onion drying process presents a high potential to improve the exergy efficiency. The sustainability index of the drying chamber varied from 1.9 to 5.1. To reduce the environmental impact of the process, the parameters must be modified in order to ameliorate the exergy efficiency of the process.

Optimal Ecological Performance Investigation of a Quantum Harmonic Oscillator Brayton Refrigerator

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaowei Liu ◽  
Lingen Chen ◽  
Shuhuan Wei ◽  
Fankai Meng
Keyword(s):  
Harmonic Oscillator ◽  
Loss Rate ◽  
Ecological Function ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Cooling Load ◽  
Ecological Performance ◽  
Heat Leakage ◽  
Classical Approximation ◽  
Quantum Friction

Abstract A model for the quantum Brayton refrigerator that takes the harmonic oscillator system as the working substance is established. Expressions of cooling load, coefficient of performance (COP), and ecological function are derived. With numerical illustrations, the optimal ecological performance is investigated. At the same time, effects of heat leakage and quantum friction are also studied. For the case with the classical approximation, the optimal ecological performance, and effects of heat leakage and quantum friction are also investigated. For both general cases and the case with classical approximation, the results indicate that the ecological function has a maximum. The irreversible losses decrease the ecological performance, while having different effects on the optimal ecological performance. For the case with classical approximation, numerical calculation with friction coefficient μ = 0.02 and heat leakage coefficient Ce = 0.01 shows that the cooling load (RE) at the maximum ecological function is 6.23% smaller than the maximum cooling load (Rmax). The COP is also increased by 12.1%, and the exergy loss rate is decreased by 27.6%. Compared with the maximum COP state, the COP (ɛE) at the maximum ecological function is 0.55% smaller than the maximum COP (ɛmax) and that makes 7.63% increase in exergy loss rate, but also makes 6.17% increase in cooling load and 6.20% increase in exergy output rate.

Design of a Multigenerational System With Absorption Cooling for a Residential Community: A Case Study

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Andre Bolt ◽  
Branson Chea ◽  
Ibrahim Dincer ◽  
Martin Agelin-Chaab ◽  
Marc Rosen
Keyword(s):  
British Columbia ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Residential Community ◽  
Heating And Cooling ◽  
Absorption Cooling ◽  
Energy And Exergy

Abstract In this paper, a multigeneration system is proposed, which utilizes geothermal energy and a lithium-bromide absorption cooling cycle. The proposed system is capable of providing electricity, heating, cooling, and domestic hot water to a small residential community in Vancouver, British Columbia, Canada. The performance of the system's heating and cooling capabilities were evaluated energetically and exergetically. A case study is presented by considering human occupancy loads and the impact of building material conditions on heating and cooling. System performance was investigated using parametric studies, where the operating conditions and ambient conditions were varied. Similar systems in the open literature were found to have an energetic and exergetic coefficient of performance (COP) of 0.8 and 0.3 for heating, while the proposed multigeneration system resulted in an energetic and exergetic coefficient of performance of 1.14 and 0.63 for heating, an increase of 30–52%. Additionally, the literature revealed that some systems resulted in an energy and exergy efficiency of 26.2% and 36.6%. The proposed multigeneration system achieved an energy and exergy efficiency of 31.86% and 63.33%, an improvement of 5.66–26.73%. The study was able to utilize the existing recommendations made by British Columbia to determine the necessary heating and cooling loads while also being able to successfully generate four useful outputs with a smaller footprint than those in the literature.

scholarly journals Performance Analysis of Multipurpose Refrigeration System (MRS) on Fishing Vessel

2016 ◽  
Vol 23 (2) ◽  
pp. 48-56 ◽  
Author(s):  
Y. Ust ◽  
A. Sinan Karakurt ◽  
U. Gunes
Keyword(s):  
Performance Analysis ◽  
Loss Rate ◽  
Industrial Applications ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Parallel Operation ◽  
Refrigeration System ◽  
Energy Saving Potential ◽  
Operation Conditions

Abstract The use of efficient refrigerator/freezers helps considerably to reduce the amount of the emitted greenhouse gas. A two-circuit refrigerator-freezer cycle (RF) reveals a higher energy saving potential than a conventional cycle with a single loop of serial evaporators, owing to pressure drop in each evaporator during refrigeration operation and low compression ratio. Therefore, several industrial applications and fish storage systems have been utilized by using multipurpose refrigeration cycle. That is why a theoretical performance analysis based on the exergetic performance coefficient, coefficient of performance (COP), exergy efficiency and exergy destruction ratio criteria, has been carried out for a multipurpose refrigeration system by using different refrigerants in serial and parallel operation conditions. The exergetic performance coefficient criterion is defined as the ratio of exergy output to the total exergy destruction rate (or loss rate of availability). According to the results of the study, the refrigerant R32 shows the best performance in terms of exergetic performance coefficient, COP, exergy efficiency, and exergy destruction ratio from among the other refrigerants (R1234yf, R1234ze, R404A, R407C, R410A, R143A and R502). The effects of the condenser, freezer-evaporator and refrigerator-evaporator temperatures on the exergetic performance coefficient, COP, exergy efficiency and exergy destruction ratios have been fully analyzed for the refrigerant R32.

Modeling and performance analysis of a hybrid conventional solar still–adsorption desalination system

2021 ◽  
pp. 095440622110007
Author(s):  
P Abhishek ◽  
V Baiju
Keyword(s):  
Performance Analysis ◽  
Hybrid System ◽  
Water Productivity ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Scale Model ◽  
Small Scale ◽  
Solar Still ◽  
And Performance

This study presents a thermodynamic modeling and performance analysis of a hybrid desalination system consisting of a conventional solar still (CSS) and an adsorption desalination system (ADS). To evaluate the performance of the system, a small scale model of a hybrid CSS-ADS system is designed, fabricated and tested under the meteorological condition of Kollam, Kerala, India. Water productivity of the hybrid CSS-ADS, followed by, assessing the coefficient of performance of the system is also carried out. The maximum water productivity of the system is estimated as 750 ml. The proposed hybrid system is able to produce the cooling effect along with desalination during its operation. The coefficient of performance (COP) is obtained as 0.58. The performance of the system is also assessed based on the second law of thermodynamics to study exergy loss and exergy efficiency of each and every component of the system. It is observed that the main sources of exergy destruction in the hybrid system occurs in the solar still basin and adsorbent bed of ADS. The total exergy loss and exergy efficiency of the hybrid system is found to be 0.224 W and 29.6%, respectively. Variation of brine water temperature, heat transfer coefficients, water productivity of CSS and ADS are also presented in this study. The study aims at a formidable solution to the low performance of conventional solar still.

Performance and Exergy Analysis of Open Absorption Heat Pump

2014 ◽  
Vol 953-954 ◽  
pp. 667-672
Author(s):  
Fan Wei ◽  
Shi Jie Zhang ◽  
Yun Han Xiao
Keyword(s):  
Heat Pump ◽  
Flue Gas ◽  
Heat Recovery ◽  
Exergy Analysis ◽  
Cooling Water ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Coefficient Of Performance ◽  
Absorption Heat Pump ◽  
Simulation Results

An open absorption heat pump(OAHP) in second type was built in this paper in order to recycle the heat and water from the flue gas. the coefficient of performance(COP) and the exergy efficiency were analyzed with the method of process simulation. Results showed the COP is 0.64, and latent heat recovery ratio is 19.6%. The temperature and humidity of flue gas, the temperature and flowrate of cooling water would influence on the COP. The increase of these parameters would lead to COP increase. The exergy efficiency of the system was 19.2%. The absorber, the generator and the condenser produce most exergy loss. The exergy efficiency of condensation was 0, which was using to recovery condensation water. The exergy efficiency would be strengthen by reducing the exergy loss of absorber and generator.

THERMODYNAMIC ANALYSIS OF SINGLE- AND DOUBLE-EFFECT ABSORPTION REFRIGERATION SYSTEMS FOR COOLING ETHANOL FERMENTATION PROCESS

2014 ◽  
Vol 22 (04) ◽  
pp. 1450020 ◽  
Author(s):  
HUGO VALENÇA DE ARAÚJO ◽  
JOSÉ VICENTE HALLAK D'ANGELO
Keyword(s):  
Thermodynamic Analysis ◽  
Fermentation Process ◽  
Alcoholic Fermentation ◽  
Double Effect ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Second Law ◽  
Base Case ◽  
Absorption Refrigeration ◽  
Single Effect

Alcoholic fermentation is one of the most important stages in industrial ethanol production process, involving a biochemical and exothermic reaction. Sometimes cooling towers are not capable of supplying a cold utility with a temperature low enough to maintain the fermentative medium temperature in a desirable range. Absorption Refrigeration Systems (ARS) appears to be a good alternative to obtain the necessary refrigeration for the fermentation process. The aim of the present paper was to carry out a thermodynamic analysis of ARS, evaluating their performance through the First and Second Laws of Thermodynamics. ARS with different configurations were studied (single-effect and double-effect with series, parallel and reverse parallel flows), all of them operating with water/lithium bromide mixture as working pair, under different operating conditions in order to satisfy the cooling load required by an industrial alcoholic fermentation process. Another objective of this paper was to investigate the risk of LiBr crystallization, which can result in scaling formation, with the aid of the solid–liquid phase equilibrium curve of H 2 O / LiBr mixture. Among the double-effect configurations studied, it was observed that series flow presents the more significant crystallization risk, which represents a limit to improve its First and Second Law performances. It was verified that the Second Law performance for the single-and double-effect ARS analyzed are similar, but their First Law performance are considerably different. This is due to the amount and quality of the heat consumed in the first effect generators of these systems. For a base case studied, First Law performance measured by coefficient of performance (COP) of double-effect ARS is 72% greater than the one for single-effect, while for Second Law performance, measured by exergetic efficiency, an increase of 5% was observed.

scholarly journals Exergy Analysis of Polymer Electrolyte Fuel Cell Systems Using Methanol

2003 ◽  
Author(s):  
Akimitsu Ishihara ◽  
Shigenori Mitsushima ◽  
Nobuyuki Kamiya ◽  
Ken-Ichiro Ota
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Steam Reforming ◽  
Waste Heat ◽  
Material Balance ◽  
Cell Voltage ◽  
Exergy Efficiency ◽  
Exergy Loss ◽  
Polymer Electrolyte Fuel Cell ◽  
The Difference

An exergy (available energy) analysis has been conducted on a typical polymer electrolyte fuel cell (PEFC) system using methanol. The material balance and enthalpy balance were calculated for the PEFC system using methanol steam reforming, and the exergy flow was obtained. Based on these results, the exergy loss in each unit was obtained, and the difference between the enthalpy and exergy was discussed. The exergy loss in this system was calculated to be 178kJ/mole MeOH for the steam reforming process of methanol. Although the enthalpy efficiency approached unity as the recovery rate of the waste heat from the cell approached unity, the exergy efficiency remained around 0.45 since the cell’s operating temperature of 80°C is low. It was also found that the cell voltage should exceed 0.82V in order to obtain the exergy efficiency of 0.5 or higher. A direct methanol fuel cell (DMFC) was analyzed using the exergy and compared with the methanol reforming PEFC. In order to obtain the exergy efficiency higher than that of PEFC with steam reforming, the cell voltage of the DMFC should be 0.48V or greater at the current density of 600mA/cm2.

scholarly journals Modelling and simulation of a solar absorption cooling system for India

2006 ◽  
Vol 17 (3) ◽  
pp. 65-70 ◽  
Author(s):  
V Mittal ◽  
K S Kasana ◽  
N S Thakur
Keyword(s):  
Surface Area ◽  
Cooling System ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Reference Temperature ◽  
Inlet Temperature ◽  
Solar Absorption ◽  
Absorption Cooling ◽  
Solar Absorption Cooling ◽  
Absorption Cooling System

This paper presents modelling and simulation of a solar absorption cooling system. In this paper, the modelling of a solar-powered, single stage, absorption cooling system, using a flat plate collector and water–lithium bromide solution, is done. A computer program has been developed for the absorption system to simulate various cycle configurations with the help of various weather data for the village Bahal, District Bhiwani, Haryana, India. The effects of hot water inlet temperatures on the coefficient of performance (COP) and the surface area of the absorption cooling component are studied. The hot water inlet temperature is found to affect the surface area of some of the system components. Moreover the effect of the reference temperature which is the minimum allowable hot water inlet temperature on the fraction of total load met by non-purchased energy (FNP) and coefficient of performance (COP) is studied and it is found that high reference temperature increases the system COP and decreases the surface area of system components but lower reference temperature gives better results for FNP than high reference temperatures.

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