Energy and exergy analyses of LiBr/H2O absorption cooling system having recto-trapezoidal profile absorber plate

Author(s):  
Rahul Roy ◽  
Balaram Kundu

This paper develops a theoretical model for energy and exergy analyses of a solar-powered Lithium-water absorption refrigeration system using a recto-trapezoidal flat plate solar collector. The effect of collector fluid inlet temperature is to examine the overall performance of the solar collector and the vapour absorption system for a wide range of design variables. The parameters computed are energy and exergy efficiencies of the solar collector plate, coefficient of performance, cooling efficiency, exergy destruction rates, thermal exergy loss rates, irreversibility, and exergetic efficiency of the absorption refrigeration cycle. The simulation results indicate that there exists an optimum inlet temperature of collector fluid for the maximum system coefficient of performance and exergetic efficiency. When the cooling system runs at this temperature, the absorber plate volume attains a minimum value. Furthermore, the performance results are significantly better when a higher absorber plate thickness parameter is for the recto-trapezoidal profile. Finally, a comparative study analyzes the collector performance parameters of an absorber plate having rectangular, triangular, or trapezoidal profile by selecting their respective parameters of geometries. When an additional constraint imposes on the plate volume, it found that using a recto-trapezoidal profile instead of a rectangular profile saves at least 30% or more collector material, and also it may have better performance than a triangular or trapezoidal profile.

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 3037 ◽  
Author(s):  
Ren ◽  
Qian ◽  
Yao ◽  
Gan ◽  
Zhang

An absorption refrigeration system (ARS) is an alternative to the conventional mechanical compression system for cold production. This study developed a novel calculation model using the Matlab language for the thermodynamic analysis of ARS. It was found to be reliable in LiCl-H2O and LiBr-H2O ARS simulations and the parametric study was performed in detail. Moreover, two 50 kW water-cooled single effect absorption chillers were simply designed to analyze their off-design behaviors. The results indicate that LiCl-H2O ARS had a higher coefficient of performance (COP) and exergetic efficiency, particularly in the lower generator or higher condenser temperature conditions, but it operated more restrictively due to crystallization. The off-design analyses revealed that the preponderant performance of LiCl-H2O ARS was mainly due to its better solution properties because the temperature of each component was almost the same for both chillers in the operation. The optimum inlet temperature of hot water for LiCl-H2O (83 °C) was lower than that of LiBr-H2O (98 °C). The cooling water inlet temperature should be controlled within 41 °C, otherwise the performances are discounted heavily. The COP and cooling capacity could be improved by increasing the temperature of hot water or chilled water properly, contrary to the exergetic efficiency.


2006 ◽  
Vol 17 (3) ◽  
pp. 65-70 ◽  
Author(s):  
V Mittal ◽  
K S Kasana ◽  
N S Thakur

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.


KnE Energy ◽  
2015 ◽  
Vol 2 (2) ◽  
pp. 22
Author(s):  
Andang Widiharto ◽  
Didit Setyo Pamuji ◽  
Atik Nurul Laila ◽  
Fiki Rahmatika Salis ◽  
Luthfi Zharif ◽  
...  

<p>Air conditioning (AC) is one of the most building’s energy consumer, included in building of Engineering Physisc’s Departement, Universitas Gadjah Mada (UGM). The declining of fossil fuel reserves and the increasing effects of global warming, forcing the world to switch to renewable energy sources. This paper discusses the design of solar absorption cooling system to replace conventional AC in seven lecture halls of Engineering Physic’s Departement, UGM. There are some steps that have been done to design the solar absorption cooling, i.e. do a study of the potential availability of solar energy, calculate the cooling loads, analyze the thermodynamic process of the system, determine the type of collector to be used and calculate area of solar collector needed. The thermal coefficient of performance (COP) of the system designed was about 0.84 which could use some types of flat plate solar collector with each area corresponding to each efficiency values. </p><p><strong>Keyword</strong> : Air conditioning; global warming; solar absorption cooling; solar collector</p>


2018 ◽  
Vol 7 (2) ◽  
pp. 94
Author(s):  
Tulus Burhanuddin Sitorus

The performance of a flat plate collector on adsorption refrigerator driven by the solar collector was investigated in the present work. Based on a study conducted no researcher studies the performance of solar collectors used in adsorption cooling system. The adsorbent used in the collector was 20 kg ordinary powder activated carbon of coconut shell produced in the Sumatera Utara province of Indonesia, 5 liters of methanol as adsorbate and 6 liters of water as the medium that was cooled. The experiments were carried out under varying weather conditions with total solar radiation about 12619-17807 kJ/m2/cycle in Medan city. The experimental results show that the values of collector efficiency obtained were about 52.11-53.92%. The values of coefficient of performance (COP) obtained were in the range of 0.0318-0.0449. The results of the statistical study suggest that the effect of the weather conditions on collector efficiency thereabout 96%.


2020 ◽  
Vol 113 ◽  
pp. 174-186 ◽  
Author(s):  
Reza Haghbakhsh ◽  
Hamed Peyrovedin ◽  
Sona Raeissi ◽  
Ana Rita C. Duarte ◽  
Alireza Shariati

2017 ◽  
Vol 6 (4) ◽  
pp. 91 ◽  
Author(s):  
Luke Ajuka ◽  
Moradeyo Odunfa ◽  
Olayinka Ohunakin ◽  
Miracle Oyewola

The experimental study investigated the energy and exergy performance of a domestic refrigerator using eco-friendly hydrocarbon refrigerants R600a and LPG (R290/R600a: 50%/50%) at 0, 0.05, 0.15 and 0.3wt % concentrations of 15nm particle size of TiO2 nano-lubricant, and R134a. The effects of evaporator temperature on power consumption, coefficients of performance, exergetic efficiency and efficiency defects in the compressor, condenser, capillary tube and evaporator of the system were examined. The results showed that LPG + TiO2 (0.15wt %) and R600a + TiO2 (0. 15wt %) had the best of performances with an average of 27.6% and 14.3% higher coefficient of Performance, 34.6% and 35.15% lower power consumption, 13.8% and 17.53% higher exergetic efficiency, a total exergetic defect of 45.8% and 64.7% lower compared to R134a. The exergetic defects in the evaporator, compressor, condenser, and capillary tube were 38.27% and 35.5%, 49.19% and 55.56%, 29.7% and 33.7%, 39.1% and 73.8% lower in the system when compared to R134a respectively. Generally, the refrigerants with nano-lubricant mixture gave better results with an appreciable reduction in the exergy defect in the compressor than the pure refrigerants, and LPG + TiO2 (0. 15wt %) gave the best result in the refrigeration system based on energy and exergy analysis.


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