Etude comparative de la performance des machines frigorifiques à absorption utilisant de l'energie thermique à très faible valeur exergétique

Thioye, Massamba

doi:10.1016/s0140-7007(97)00007-8

Cited by 9 publications

(1 citation statement)

References 9 publications

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“…The water-lithium bromide solution is highly corrosive and extremely viscous and viscosity-reducing agents are frequently required. The limitations of using common working fluids [2] for utilizing low potential heat sources (80-120°C) for cooling and refrigeration (< 0°C) are therefore self-evident.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer to sub-cooled binary solution in horizontal tube

Orian

Jelínek

Levy

2009

Applied Thermal Engineering

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Predicted heat transfer coefficients (HTC) are widely used for calculations of various heat transfer processes. Various empirical and semi-empirical models of non-dimensional groups are used for calculating the heat transfer coefficients. The common accuracy of the predicted heat transfer coefficient is usually about ±25%; however, the accuracy is failing by the inaccurate predictions of the fluid properties.In the present study the heat transfer coefficient of subcooled organic mixture chlorodifluoromethane (R22) -dimethylacetamide (DMAC) were predicted. While the solution's pressure-temperature-concentration, densitytemperature-concentration and viscosity-temperatureconcentration relations were previously measured in our laboratory and the heat capacity were calculated from the enthalpy of the solution, the only unknown property that was required for predicting the HTC was the mixture thermal conductivity. Various correlations and mixing rules for the mixture thermal conductivity were adopted for predicting the heat transfer coefficient. In order to validate the predicted heat transfer coefficients, an experimental system was designed, built and successfully operated. The heat transfer coefficient was measured experimentally and compared with the predicted one. Based on this comparison the best fitted thermal conductivity for the working fluid (R22-DMAC) is recommended. As a result, the deviations of the predicted heat transfer coefficients, obtained by the well-known Dittus-Boelter equation, from the experimental values were less than 15%.

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Section: Introductionmentioning

confidence: 99%

Heat transfer to sub-cooled binary solution in horizontal tube

Orian

Jelínek

Levy

2009

Applied Thermal Engineering

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An improved absorption refrigeration cycle driven by unsteady thermal sources below 100�C

Wang

Gao

Chen

2000

Int. J. Energy Res.

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Thermodynamic study of multistage absorption cycles using low-temperature heat

Venegas

Izquierdo

Vega

et al. 2002

Int. J. Energy Res.

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SUMMARYThe use of low-temperature heat (between 50 and 908C) is studied to drive absorption systems in two different applications: refrigeration and heat pump cycles. Double-and triple-stage absorption systems are modelled and simulated, allowing a comparison between the absorbent-refrigerant solutions H 2 O-NH 3 , LiNO 3 -NH 3 and NaSCN-NH 3 . The results obtained for the double-stage cycle show that in the refrigeration cycle the LiNO 3 -NH 3 solution operates with a COP of 0.32, the H 2 O-NH 3 pair with a COP of 0.29 and the NaSCN-NH 3 solution with a COP of 0.27, when it evaporates at À158C, condenses and absorbs refrigerant at 408C and generates vapour at 908C. The results are presented for double-and triplestage absorption systems with evaporation temperatures ranging between À40 and 08C and condensation temperatures ranging from 158C to 458C.The results obtained for the double-stage heat pump cycle show that the LiNO 3 -NH 3 solution reaches a COP of 1.32, the NaSCN-NH 3 pair a COP of 1.30 and the H 2 O-NH 3 mixture a COP of 1.24, when it condenses and absorbs refrigerant at 508C, evaporates at 08C and generates vapour at 908C. For the double-and triple-stage cycles, the results are presented for evaporation temperatures ranging between 0 and 158C. The minimum temperature required in the generators to operate the refrigeration and heat pump cycles are also presented.

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Etude comparative de la performance des machines frigorifiques à absorption utilisant de l'energie thermique à très faible valeur exergétique

Cited by 9 publications

References 9 publications

Heat transfer to sub-cooled binary solution in horizontal tube

Heat transfer to sub-cooled binary solution in horizontal tube

An improved absorption refrigeration cycle driven by unsteady thermal sources below 100�C

Thermodynamic study of multistage absorption cycles using low-temperature heat

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