Performance of a Single Effect Solar Absorption Cooling System (Libr-H2O)

Ketfi, Omar; Merzouk, M.; Merzouk, Nachida Kasbadji; Metenani, S. El

doi:10.1016/j.egypro.2015.07.534

Cited by 32 publications

(20 citation statements)

References 8 publications

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“…The mathematical model represented in [11] for H 2 0/LiBr operation predicts COP th = 0.77 for T s = 90 ºC, T c = 40 ºC and T AC = 7 ºC, this set of conditions repeats the data of the experimental measurements in Finland [3] with very similar thermal COP considered above. However, this model does not cover electrical energy consumption expressed by ESF or EER.…”

Section: Methodssupporting

confidence: 54%

“…Balancing the absorption chiller output and the cooling power consumption is possible by using the cold water storage 6 in Fig.2. The calculation results according to equations (10)(11)(12) and the experimental data [3] are presented in Fig. 3.…”

Section: Resultsmentioning

confidence: 99%

“…where A 0 , A 1 and A2 -collector constants from data sheet [11]; I -solar radiation in plane of collector array, W·m -2 ; η col -solar collector efficiency (unitless); T mean -mean temperature of flow in solar collector, ºC; T amb -ambient air temperature near collector array, ºC.…”

Section: T Ac T C T Smentioning

confidence: 99%

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Evaluation of solar sorption refrigeration system performance in Latvia

Rusovs¹,

Jaundālders²,

Stanka³

2017

Engineering for Rural Development

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Abstract. There are many well known researches and commercial products for solar air-conditioning (SAC) units of small and medium power (up to 100 kW). Solar energy application for refrigeration by using of the sorption cycle for Latvian climate conditions was considered in the presented paper. Advantages of lithiumbromide and ammonia-water fluids were compared taking in account the difference between real and ideal performance of the sorption systems. Since heat rejection in thermally driven chillers is bigger than in conventional vapor compression refrigeration, the climate conditions have big influence on the total system performance. As the solar radiation level in Latvia is less than 400 W·m -2 dual sources of driving heat (biofuel combustion and solar energy) for the sorption cycle were evaluated. Computer modeling of sorption chillers results in development of a new temperature threshold criterion for efficient use of solar cooling systems at different energy costs and various temperature levels.Keywords: solar energy, air-conditioning, refrigeration, absorption, adsorption. IntroductionSolar energy from the sun heat collector can provide the thermal driving power for different sorption refrigeration cycles.In case of absorption process refrigerant vapor after evaporator (cooling duty) becomes incorporated in liquid mixture forming strong solution in the absorber (exothermic process) and in the desorber refrigerant steam left solution by endothermic reaction is supported by external heat from the solar collector. In the aqua ammonia (NH 3 /H 2 O) refrigeration cycle water performs as an absorbent and ammonia is used as the refrigerant agent. This mixture can provide refrigeration to negative temperature up to -60 ºC. The second common pair is water-lithium bromide solution(H 2 O/LiBr), where water servesas the refrigerant agent and strong mixture (H 2 O/LiBr) performs as absorber.The sorption cyclescan be realized also by the adsorption process, when gas (the refrigerant) interacts with a solid body (the adsorbent) by physical or chemical forces. The mostly used pairs are represented by silica gel-waterandzeolite-water.The absorption and adsorption systems are mainly used for close cooling cycles. Desiccant cooling, which consists of combination of dehumidification and evaporation processes, is used in case of the open sorption cycle. In this case, fresh and warm air is directly involved in the process. There are solid and liquid desiccations used in cooling.Market research shows that the absorption cycle takes about 71 % share of all solar sorption chillers market, the desiccant cooling share is 16 % and the rest13 % belong to the adsorption system.For efficiency indicators SF (solar fraction), COP (coefficient of performance) and seasonal SCOP or solar thermal COP th represented by the ratio of the cooling energy and heat from the solar collector during the cooling season are used. Electrical energy consumption described by COP el representsthe ratio of cooling energy per unit of the consumed electrical...

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Section: Methodssupporting

confidence: 54%

Section: Resultsmentioning

confidence: 99%

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Evaluation of solar sorption refrigeration system performance in Latvia

Rusovs¹,

Jaundālders²,

Stanka³

2017

Engineering for Rural Development

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“…[30][31][32] The efficiency of absorption cooling systems can further be improved by two to three times by adopting a solar steam regeneration method on absorbent solutions. 33 Ketfi et al 34 calculated that the COP of a 70 kW Yazaki absorption cooling machine working with water-lithium bromide mixture, has reached a maximum of 0.77 at a generator temperature of 92 C. Two generators coupled in series to increase the amount of refrigerant vapour for an equivalent amount of heat input in a series flow double effect LiBr-H 2 O absorption system. 35 It observed that double-effect systems have a higher COP value of 1-1.28 than the single effect absorption systems.…”

Section: Introductionmentioning

confidence: 99%

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

Roy

Kundu

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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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.

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“…Mathematical methods were employed to calculate solar collector efficiency in order to be used as an input parameter in transient system software or analytical methods for solar cooling systems [5,18]. In most research, thermal efficiency was calculated without taking into account the flowrate of the solar collector, which affects the accuracy of the overall evaluation of the solar cooling system.…”

Section: Introductionmentioning

confidence: 99%

Determining the Effect of Inlet Flow Conditions on the Thermal Efficiency of a Flat Plate Solar Collector

Alobaid

Hughes

Heyes

et al. 2018

Fluids

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The main objective of this study was to investigate the effect of inlet temperature (Tin) and flowrate ( m ˙ ) on thermal efficiency ( η t h ) of flat plate collectors (FPC). Computational Fluid Dynamics (CFD) was employed to simulate a FPC and the results were validated with experimental data from literature. The FPC was examined for high and low level flowrates and for inlet temperatures which varied from 298 to 373 K. Thermal efficiency of 93% and 65% was achieved at 298 K and 370 K inlet temperature’s respectively. A maximum temperature increase of 62 K in the inlet temperature was achieved at a flowrate of 5 × 10−4 kg/s inside the riser pipe. Tin and m ˙ were optimised in order to achieve the minimum required feed temperature for a 10 kW absorption chiller.

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Performance of a Single Effect Solar Absorption Cooling System (Libr-H2O)

Cited by 32 publications

References 8 publications

Evaluation of solar sorption refrigeration system performance in Latvia

Evaluation of solar sorption refrigeration system performance in Latvia

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

Determining the Effect of Inlet Flow Conditions on the Thermal Efficiency of a Flat Plate Solar Collector

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Performance of a Single Effect Solar Absorption Cooling System (Libr-H2O)

Cited by 32 publications

References 8 publications

Evaluation of solar sorption refrigeration system performance in Latvia

Evaluation of solar sorption refrigeration system performance in Latvia

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

Determining the Effect of Inlet Flow Conditions on the Thermal Efficiency of a Flat Plate Solar Collector

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