Maximum Exergetic Efficiency Operation of a Solar Powered H2O-LiBr Absorption Cooling System

Stanciu, Camelia; Stanciu, Dorin; Gheorghian, Adina-Teodora; Tănase, Elena-Beatrice; Dobre, Cătălina; Spiroiu, Marius Adrian

doi:10.3390/e19120676

Cited by 5 publications

(10 citation statements)

References 19 publications

(22 reference statements)

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“…According to the author's results, for the longest continuous operation of the NH 3 -H 2 O cooling system (from 09:00 to 17:10) 10 m × 2.9 m parabolic trough collector (PTC) aperture dimensions with a 0.16 m 3 storage tank volume were calculated at 10 • C of evaporator temperature. In the same year, Stanciu et al [4] simulated a solar driven cooling system consisting of a single effect H 2 O-LiBr absorption cooling system, a parabolic trough collector, and a storage tank module was analyzed for one full operation day. The simulation was constrained to operate at the maximum exergetic efficiency of the absorption system, under a time-dependent cooling load.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Simulation of an Absorption Cooling System with Different Working Mixtures

et al. 2018

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High consumption of electricity represents an economic and social problem in warm places, caused by the massive use of cooling machines. Absorption systems are a sustainable method for air conditioning applications. However, environmental conditions should be analyzed to avoid crystallization problems of the working mixture. This article presents a thermal analysis of a solar absorption cooling system in dynamic conditions using NH 3 -H 2 O, H 2 O-LiBr, NH 3 -NaSCN, NH 3 -LiNO 3 , and H 2 O-LiCl working mixtures using Equation Engineering Solver (EES) and TRaNsient SYstem Simulation (TRNSYS) software. A solar collector area of 42.5 m 2 was selected to carry out the thermal analysis. The results showed that H 2 O-LiCl obtained the maximum solar (0.67) and minimum heating (0.33) fraction. However, it obtained the maximum lost heat fraction (0.12), in spite of obtaining the best coefficient of performance (COP) among the other working mixtures, due mainly to a crystallization problem. The gain fraction (GF) parameter was used to select the adequate solar collector number for each working mixture. NH 3 -LiNO 3 and NH 3 -H 2 O obtained the highest GF (up 6), and both obtained the maximum solar (0.91) and minimum heating (0.09) fraction, respectively, using 88.8 and 100.4 m 2 of solar collector area, respectively.

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Section: Introductionmentioning

confidence: 99%

Dynamic Simulation of an Absorption Cooling System with Different Working Mixtures

et al. 2018

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“…The most widespread version of LiBr-H2O SACS is the single effect one and several studies are dedicated to this type of equipment by experiment [4,11] or by modelling [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Another operating problem of SACS is providing a minimum concentrations difference between the diluted and the concentrated solution, named degassing zone. This parameter is important because the solutions flow rates depend on the degassing zone, and low values of degassing zone determines high solutions flow rates [7,10,13]. Despite the dependence between the degassing zone and the solutions flow rates for the LiBr-H2O, recommendations for the minimum acceptable degassing zone are not available in the literature.…”

Section: Introductionmentioning

confidence: 99%

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New Perspective on Performances and Limits of Solar Fresh Air Cooling in Different Climatic Conditions

Abrudan¹,

Pop²,

Şerban³

et al. 2019

Preprint

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The study carried out by simulation, concerns the thermal behavior of an office building’s solar fresh air cooling system, based on a LiBr-H2O absorption chiller in different climatic conditions. The coefficient of performance (COP) and the solar fraction were considered performance parameters and were analyzed with respect to the operating limits: risk of crystallization and maintaining at least a minimum degassing zone. A new correlation between the required solar hot temperature and the cooling water temperature was established and then embedded in another new correlation between the COP and the cooling water temperature that was used in simulations during the whole cooling season corresponding to each location. It was found that: the solar hot water should be maintained in the range of (80-100) °C depending on the cooling water temperature, the COP of the solar LiBr-H2O absorption chiller with or without cold storage tank can reach (76.5-82.4) % depending on the location, and the solar fraction can reach (29.5-62.0) % without cold storage tank and can exceed 100 % with cold storage tank, the excess cooling power being available to cover other types of cooling loads: through the building envelope, from lighting, from occupants, etc.

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“…As the water tank temperature was very sensitive to ACS load, instability in system daily operation was emphasized. Thus, the importance of ensuring a constant temperature for the ACS desorber was found as being crucial not only for the system performances, but also for the system operation [10][11][12]. PCM storage could be used instead to maintain a constant input temperature to the ACS desorber.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of a phase change material melting process

Stanciu

Apostol

et al. 2019

E3S Web Conf.

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Storage processes are usually integrated in solar energy systems applications due to daily variation of this energy source availability. Among different thermal storage solutions, phase change materials (PCM) lately became more extensively used covering a wide range of operating temperatures. In this regard, a numerical simulation of a PCM melting process is performed under ANSYS CFD environment. A particular configuration is considered consisting in a 2m length annular tube having a 5.48 cm external diameter. The tube is filled with paraffin chosen as PCM. A concentric interior tube of 2.54 cm diameter is used for transporting the heat transfer fluid (HTF) from the solar collector. Heat is transferred through the 1 mm thick pipe wall to the PCM placed all around the HTF tube. The numerical results reveal the melting process of the PCM at different instances and tube sections. The time variation of the PCM liquid fraction is emphasized. The results describe the dynamic behavior of a PCM melting process and might be further integrated in any solar power plant storage charging process simulation.

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Maximum Exergetic Efficiency Operation of a Solar Powered H2O-LiBr Absorption Cooling System

Cited by 5 publications

References 19 publications

Dynamic Simulation of an Absorption Cooling System with Different Working Mixtures

Dynamic Simulation of an Absorption Cooling System with Different Working Mixtures

New Perspective on Performances and Limits of Solar Fresh Air Cooling in Different Climatic Conditions

Numerical simulation of a phase change material melting process

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