The Experts below are selected from a list of 75 Experts worldwide ranked by ideXlab platform

Guangming Chen - One of the best experts on this subject based on the ideXlab platform.

  • Experimental study on two-stage ejector refrigeration system driven by two heat sources.
    International Journal of Refrigeration, 2017
    Co-Authors: Guangming Chen, Rongtao Zhang, Daibin Zhu, Chen Shaojie, Fang Lingyun, Xinyue Hao
    Abstract:

    Abstract In this paper, an experimental study on a two-stage ejector refrigeration system driven by two heat sources is carried out involving system design, setup, operation and experimental evaluation. It is looked at by means of changing temperatures of evaporation, condensation, low and high temperature generation independently for the variation tendency of system performance (including total entrainment ratio and COP) and comparison to the conventional single-stage ejector refrigeration system at variable condensation temperatures that is achieved by the valve switching in this system. In terms of refrigerants, R236fa is selected for stability of the system operation. Total entrainment ratio and COP are increasing as the temperatures of evaporation, high and low temperature generation go up. Different from the conventional single-stage ejector refrigeration system, this two-stage system is finally found to be capable of supplying more Refrigerating Effect in situations where the condensation temperature is lower than 21.7 °C.

  • an investigation of the mixing position in the recuperators on the performance of an auto cascade refrigerator operating with a rectifying column
    Cryogenics, 2012
    Co-Authors: Qin Wang, Jiangpu Wang, Fusheng Chen, Guangming Chen
    Abstract:

    Abstract Based on case studies, the paper investigated the influence of the low pressure refrigerant mixing position in recuperators on the performance of an auto-cascade refrigerator operating with a rectifying column in theory and experiment. From temperature profiles in recuperators with the heat recuperated, a stable region and two unstable regions was found along the recuperators. When the mixing position is within the stable region, the specific Refrigerating Effect determined by the pinch point of recuperators can be obtained at the specified Refrigerating temperature. But the given Refrigerating temperature cannot be maintained for the same specific Refrigerating Effect when the mixing position is within the unstable region. In the stable region, the optimum mixing position with the minimum heat transfer area required for the given specific Refrigerating Effect exists. The average temperature difference of the high and low pressure refrigerants within the recuperators is the largest as well as the heat recuperated for the optimum mixing position. Experimental results agree with key points of the theoretical analysis. The new approach employed and results obtained in the paper will be valuable to the optimum design and application of the auto-cascade refrigerator in future.

  • an investigation of the mixing position in the recuperators on the performance of an auto cascade refrigerator operating with a rectifying column
    Cryogenics, 2012
    Co-Authors: Qin Wang, Jiangpu Wang, Fusheng Chen, Guangming Chen
    Abstract:

    Abstract Based on case studies, the paper investigated the influence of the low pressure refrigerant mixing position in recuperators on the performance of an auto-cascade refrigerator operating with a rectifying column in theory and experiment. From temperature profiles in recuperators with the heat recuperated, a stable region and two unstable regions was found along the recuperators. When the mixing position is within the stable region, the specific Refrigerating Effect determined by the pinch point of recuperators can be obtained at the specified Refrigerating temperature. But the given Refrigerating temperature cannot be maintained for the same specific Refrigerating Effect when the mixing position is within the unstable region. In the stable region, the optimum mixing position with the minimum heat transfer area required for the given specific Refrigerating Effect exists. The average temperature difference of the high and low pressure refrigerants within the recuperators is the largest as well as the heat recuperated for the optimum mixing position. Experimental results agree with key points of the theoretical analysis. The new approach employed and results obtained in the paper will be valuable to the optimum design and application of the auto-cascade refrigerator in future.

  • cycle performance studies on a new hfc 161 125 143a mixture as an alternative refrigerant to r404a
    Journal of Zhejiang University Science, 2012
    Co-Authors: Yingjie Xu, Menyuan Zhao, Q Wang, Guangming Chen
    Abstract:

    In this paper, a new ternary non-azeotropic mixture of HFC-161/125/143a (0.15/0.45/0.40 in mass fraction), as a promising mixed refrigerant to R404A, is presented. The ozone depletion potential (ODP) of the new refrigerant is zero and its basic thermodynamic properties are similar to those of R404A, but its global warming potential (GWP) is much smaller than those of R507A and R404A. Meanwhile, theoretical calculations show that, under the working condition I (the average evaporation temperature: −23 °C, the average condensing temperature: 43 °C, the superheat temperature: 28 °C, the subcooling temperature: 5 °C), the volumetric Refrigerating Effect and specific Refrigerating Effect of the new mixture are 2.33% and 15.48% higher, respectively, than those of R404A. The coefficient of performance (COP) of the new mixture is 5.19% higher than that of R404A and the pressure ratio of the new mixture is 0.82% lower than that of R404A. Equally, under the working condition II (the average evaporation temperature: −40 °C, the average condensing temperature: 35 °C, the superheating temperature: 30 °C, the subcooling temperature: 5 °C), the volumetric Refrigerating Effect and specific Refrigerating Effect of the new mixture are 2.24% and 20.58% higher, respectively, than those of R404A. The COP of the new mixture is 4.60% higher than that of R404A and the pressure ratio of the new mixture is similar to that of R404A. The performances of the new mixture and R404A are compared in a vapor compressor refrigeration apparatus originally designed for R404A under several working conditions (condensing temperatures: 35–45 °C, evaporation temperatures: −40–−20 °C). Experimental results show that the new mixture can obtain a higher COP, by 6.3% to 12.1%, and a lower pressure ratio, by 1.8% to 6.6%, compared to R404A; although the discharge temperature of the new mixture is slightly higher than that of R404A. The advantages of the new mixture will be further verified in the actual system.

Predrag Stojan Hrnjak - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the condenser subcooling on the performance of vapor compression systems
    International Journal of Refrigeration-revue Internationale Du Froid, 2015
    Co-Authors: Gustavo Pottker, Predrag Stojan Hrnjak
    Abstract:

    Abstract This paper presents a theoretical study about the Effect of condenser subcooling on the performance of vapor-compression systems. It is shown that, as condenser subcooling increases, the COP reaches a maximum as a result of a trade-off between increasing Refrigerating Effect and specific compression work. The thermodynamic properties associated with the relative increase in Refrigerating Effect, i.e. liquid specific heat and latent heat of vaporization, are dominant to determine the maximum COP improvement with condenser subcooling. Refrigerants with large latent heat of vaporization tend to benefit less from condenser subcooling. For an air conditioning system, results indicate that the R1234yf (+8.4%) would benefit the most from condenser subcooling in comparison to R410A (7.0%), R134a (5.9%) and R717 (2.7%) due to its smaller latent heat of vaporization. On the other hand, the value of COP maximizing subcooling does not seem to be a strong function of thermodynamic properties.

Maamar Ouali - One of the best experts on this subject based on the ideXlab platform.

  • design and realization of a solar adsorption refrigeration machine powered by solar energy
    Energy Procedia, 2014
    Co-Authors: Mohand Berdja, Brahim Abbad, Ferhat Yahi, Fateh Bouzefour, Maamar Ouali
    Abstract:

    Abstract This work aims to the experimental realization of a refrigerator prototype that uses an adsorption tube collector for cooling, in which solar energy can be directly absorbed. The development of a software giving an estimate of the activated carbon and methanol quantities in the refrigeration system, the quantities of energy used in its various parts, their design, the refrigeration and solar performance coefficient was carried out, and this according to the temperature data, total radiation and the dimension of the refrigeration compartment to be cooled. The thermal COP of the prototype was founded equal to 0.49 depending thus on the Refrigerating Effect and the energy absorbed in the collector-adsorbor. The solar COP was founded equal to 0.081 depending on the Refrigerating Effect and the solar radiation.

Gustavo Pottker - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the condenser subcooling on the performance of vapor compression systems
    International Journal of Refrigeration-revue Internationale Du Froid, 2015
    Co-Authors: Gustavo Pottker, Predrag Stojan Hrnjak
    Abstract:

    Abstract This paper presents a theoretical study about the Effect of condenser subcooling on the performance of vapor-compression systems. It is shown that, as condenser subcooling increases, the COP reaches a maximum as a result of a trade-off between increasing Refrigerating Effect and specific compression work. The thermodynamic properties associated with the relative increase in Refrigerating Effect, i.e. liquid specific heat and latent heat of vaporization, are dominant to determine the maximum COP improvement with condenser subcooling. Refrigerants with large latent heat of vaporization tend to benefit less from condenser subcooling. For an air conditioning system, results indicate that the R1234yf (+8.4%) would benefit the most from condenser subcooling in comparison to R410A (7.0%), R134a (5.9%) and R717 (2.7%) due to its smaller latent heat of vaporization. On the other hand, the value of COP maximizing subcooling does not seem to be a strong function of thermodynamic properties.

Mohand Berdja - One of the best experts on this subject based on the ideXlab platform.

  • design and realization of a solar adsorption refrigeration machine powered by solar energy
    Energy Procedia, 2014
    Co-Authors: Mohand Berdja, Brahim Abbad, Ferhat Yahi, Fateh Bouzefour, Maamar Ouali
    Abstract:

    Abstract This work aims to the experimental realization of a refrigerator prototype that uses an adsorption tube collector for cooling, in which solar energy can be directly absorbed. The development of a software giving an estimate of the activated carbon and methanol quantities in the refrigeration system, the quantities of energy used in its various parts, their design, the refrigeration and solar performance coefficient was carried out, and this according to the temperature data, total radiation and the dimension of the refrigeration compartment to be cooled. The thermal COP of the prototype was founded equal to 0.49 depending thus on the Refrigerating Effect and the energy absorbed in the collector-adsorbor. The solar COP was founded equal to 0.081 depending on the Refrigerating Effect and the solar radiation.