Thermodynamic analysis of transcritical CO2 booster refrigeration systems in supermarket

Ge, Y.T.; Tassou, S.A.

doi:10.1016/j.enconman.2010.11.015

Cited by 107 publications

(42 citation statements)

References 10 publications

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“…Designed refrigeration system, including only one circuit at MT and LT levels with CO2 as only refrigerant is simple and cheap in comparison to the cascade system (Ge and Tassou, 2011). The performance of the CO 2 system depends on the surrounding temperature, which determines working condition of CO 2 in transcritical, or subcritical mode.…”

Section: R744 Transcritical Booster Systemmentioning

confidence: 99%

Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module

Haida

Banasiak

Smołka

et al. 2016

International Journal of Refrigeration

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Aim of this thesis is to present an experimental investigation of standard R744 supermarket refrigeration system, with the high-pressure electronic valve (HPV), and refrigeration system with multi-ejector expansion pack on the same vapour compression rack. Comparison of the R744 multi-ejector refrigeration system, was carried out based on energy performance characteristics: refrigeration capacity, power consumption, COP, and exergy efficiency. Apart from the system performance comparison, influence of the pressure level in the flash tank on the system performance for both alternatives was analysed.The experimental results indicated COP and exergy efficiency improvement of the multiejector refrigeration system up to 7% and 13.7%, respectively. The multi-ejector system was able to operate in smaller range of the tanks pressure lift than the standard system dependent on the refrigeration load and the exit gas cooler section parameters. The highest values of COP and exergy efficiency were obtained by the multi-ejector refrigeration system for the tanks pressure lift value close to the limit value. The values of the overall compressor efficiencies were significantly differentiated, dependent on the operation module (cooling load and heat rejection conditions), which strongly influenced the values of COP and exergy efficiency. Therefore, it was not possible to clearly define the optimum pressure in the flash tank. It was concluded that improvement of compressors efficiencies utilized in the multiejector system will indicate high energy performance of the refrigeration system.

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Section: R744 Transcritical Booster Systemmentioning

confidence: 99%

Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module

Haida

Banasiak

Smołka

et al. 2016

International Journal of Refrigeration

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“…In Denmark, most newly built refrigeration plants are designed much like the one previously presented in literature [8,28]. The refrigerant is Carbon Dioxide (R744).…”

Section: Numerical Modelmentioning

confidence: 99%

Two Thermoeconomic Diagnosis Methods Applied to Representative Operating Data of a Commercial Transcritical Refrigeration Plant

Ommen

Sigthorsson

Elmegaard

2017

Entropy

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Abstract:In order to investigate options for improving the maintenance protocol of commercial refrigeration plants, two thermoeconomic diagnosis methods were evaluated on a state-of-the-art refrigeration plant. A common relative indicator was proposed for the two methods in order to directly compare the quality of malfunction identification. Both methods were applicable to locate and categorise the malfunctions when using steady state data without measurement uncertainties. By introduction of measurement uncertainty, the categorisation of malfunctions became increasingly difficult, though depending on the magnitude of the uncertainties. Two different uncertainty scenarios were evaluated, as the use of repeated measurements yields a lower magnitude of uncertainty. The two methods show similar performance in the presented study for both of the considered measurement uncertainty scenarios. However, only in the low measurement uncertainty scenario, both methods are applicable to locate the causes of the malfunctions. For both the scenarios an outlier limit was found, which determines if it was possible to reject a high relative indicator based on measurement uncertainty. For high uncertainties, the threshold value of the relative indicator was 35, whereas for low uncertainties one of the methods resulted in a threshold at 8. Additionally, the contribution of different measuring instruments to the relative indicator in two central components was analysed. It shows that the contribution was component dependent.

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“…The receiver pressure is regulated by the high pressure valve CP HP. The detailed thermodynamic analysis of such systems is described in [9]. …”

Section: A Co 2 Booster Refrigeration Systemmentioning

confidence: 99%

Model predictive control for flexible power consumption of large-scale refrigeration systems

Shafiei

Stoustrup

Rasmussen

2014

2014 American Control Conference

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Abstract-A model predictive control (MPC) scheme is introduced to directly control the electrical power consumption of large-scale refrigeration systems. Deviation from the baseline of the consumption is corresponded to the storing and delivering of thermal energy. By virtue of such correspondence, the control method can be employed for regulating power services in the smart grid. The proposed scheme contains the control of cooling capacity as well as optimizing the efficiency factor of the system, which is in general a nonconvex optimization problem. By introducing a fictitious manipulated variable, and novel incorporation of the evaporation temperature set-point into optimization problem, the convex optimization problem is formulated within the MPC scheme. The method is applied to a simulation benchmark of large-scale refrigeration systems including several medium and low temperature cold reservoirs.

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Thermodynamic analysis of transcritical CO2 booster refrigeration systems in supermarket

Cited by 107 publications

References 10 publications

Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module

Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module

Two Thermoeconomic Diagnosis Methods Applied to Representative Operating Data of a Commercial Transcritical Refrigeration Plant

Model predictive control for flexible power consumption of large-scale refrigeration systems

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