Results 161 to 170 of about 703,374 (204)
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Heat pump control with zeotropic mixtures
1999Zeotropic mixtures offer the possibility of being changed in composition by rectification methods which can be applied to the control of heat pump systems. Cycle calculations were done with various fluids commercially available in order to find the best mixture combination under the aspect of a wide control range as well as of a maximum achievable COP.
Halm NP, Kruse H, Bobbo S, Camporese R
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Simulation of Isothermal and Adiabatic Leak Processes of Zeotropic Refrigerant Mixtures
HVAC&R Research, 1995Nonflammable zeotropic mixtures of flammable and nonflammable refrigerants are possible alternative refrigerants for use in domestic heat pumps and air conditioners. Refrigerant leakage from such a system is of paramount concern since it is possible that a mixture composition will shift to a flammable range.
M. S. Kim, D. A. Didion
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International Journal of Refrigeration, 1999
Abstract In a recent study, it was shown by the authors that perfect glide matching of heat transfer fluid and the refrigerant is difficult in condensers and evaporators for many zeotropic mixtures and also that pinch points can occur in both the condensers and evaporators due to the non-linear variation of enthalpy during phase change.
G Venkatarathnam, S Srinivasa Murthy
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Abstract In a recent study, it was shown by the authors that perfect glide matching of heat transfer fluid and the refrigerant is difficult in condensers and evaporators for many zeotropic mixtures and also that pinch points can occur in both the condensers and evaporators due to the non-linear variation of enthalpy during phase change.
G Venkatarathnam, S Srinivasa Murthy
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Theoretical evaluation of performance of zeotropic mixtures in refrigerating cycles
1995Zeotropic mixtures sometimes in the past have been proposed in order to improve the energy efficiency of refrigeration processes when a fluid need to be cooled in an extended tem¬perature range; moreover they offer also the possibility of a stepless and energy effective capacity modulation, by means of a change in the composition of the operating fluid,
S. Bobbo +3 more
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Potential of zeotropic mixtures as working fluids in organic Rankine cycles
Energy, 2012Abstract The effect of using mixtures as working fluids in organic Rankine cycles (ORCs) is examined with a simulation model of the cycle that includes all elements of an actual installation. We consider several of the commonly used pure ORC fluids as potential components, discuss a mixture selection method, and suggest optimal concentrations.
M. Chys +3 more
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Zeotropic mixture active design method for organic Rankine cycle
Applied Thermal Engineering, 2018Abstract Using mixture working fluids has been proven to be an effective way to improve the performance of organic Rankine cycles (ORC). Instead of recommending mixtures or compositions for a specific heat source, this work is focused on providing preliminary design guidelines of zeotropic mixture working fluids for ORC.
Huixing Zhai, Qingsong An, Lin Shi
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Konovalov’s first law validity for nonideal multicomponent zeotropic mixtures
Theoretical Foundations of Chemical Engineering, 2008Complete conditions for the validity of Konovalov’s first law in nonideal multicomponent zeotropic systems are found.
L. A. Serafimov +2 more
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Evaluation of Zeotropic Refrigerant Mixtures R32/R134A in Flow Condensation
Advanced Energy Systems, 1997Abstract Experiments on flow condensation have been conducted with pure R32, R134a and R32/R134a mixtures. The results have been represented in form of local and mean heat transfer coefficient, as well as pressure drop. The heat transfer data is compared with the prediction from correlations in literature. An analysis is also carried out
D. W. Shao, E. Granryd
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Condensation of ternary low GWP zeotropic mixtures inside channels
International Journal of Refrigeration, 2019Abstract The condensation heat transfer coefficient and two-phase frictional pressure drop of ternary zeotropic mixtures R455A (R32, R1234yf and R744 at 21.5/75.5/3.0% by mass composition) and R452B (R32, R1234yf and R125 at 67.0/26.0/7.0% by mass composition) have been measured inside a minichannel (0.96 mm diameter) and a conventional tube (8.0 mm ...
Azzolin, Marco +4 more
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At Nucleate Boiling Heat Transfer Zeotropic Mixtures A Horizontal Tubes
Siberian Journal of Physics, 2016Despite numerous empirical relationships, currently there is no sufficiently reliable and physically reasonable methodology for calculating the heat transfer coefficient at boiling the zeotropic binary blends. The main reason is the complexity of the boiling process mechanism. Zeotropic blends have the non-isothermal phase transition or the temperature
Nadezhda Mezentseva +2 more
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