scholarly journals Optimization of the Refrigerant Charge and the Expansion Valve Opening for the Soft Ice Cream Machine Using R-404A

2016 ◽  
Vol 17 (8) ◽  
pp. 728-734 ◽  
Author(s):  
Nae-Hyun Kim
Keyword(s):  
Ice Cream ◽  
Expansion Valve ◽  
Valve Opening

Application of the Natural Refrigerant Mixture R-290/DME to a Soft Ice Cream Refrigerator

2016 ◽  
Vol 24 (04) ◽  
pp. 1650027 ◽  
Author(s):  
Nae-Hyun Kim
Keyword(s):  
Ozone Depletion ◽  
Ice Cream ◽  
Formation Time ◽  
Actual Usage ◽  
Refrigerant Mixture ◽  
Expansion Valve ◽  
Valve Opening ◽  
Natural Refrigerant ◽  
Optimum Charge

Due to the ozone depletion issue, R-502, which had long been used as the refrigerant of an ice cream refrigerator, has been replaced by R-404A. However, global warming potential (GWP) of R-404A is high, and thus, a replacement refrigerant is necessary in the long term. Natural refrigerants, such as R-290 or DME (dimethylether), could be a choice. In this study, an ice cream refrigerator cycle was optimized using R-290/DME mixture (mass fraction 65/35). The optimization was accomplished through a search for the proper refrigerant charge amount and the opening of the expansion valve. For the present ice cream refrigerator having 2.8[Formula: see text]L freezer volume, the optimum charge amount was 900[Formula: see text]g, and the optimum valve opening was [Formula: see text]120[Formula: see text]. At this configuration, the ice cream formation time was 3[Formula: see text] 6[Formula: see text] and COP was 2.0. The ice cream formation time was much shorter than when R-404A was used, and the COP was increased by more than 100%. For actual usage of the refrigerant, however, the flammability issue of the R-290/DME mixture should be cleared.

Research on Electronic Expansion Valve Opening Mechanical Properties of Multi-Link Inverter Air-Con Based on Neural Network

2013 ◽  
Vol 644 ◽  
pp. 64-67
Author(s):  
Li Hui Guo ◽  
Wan Qiang Hu
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Pid Controller ◽  
Control Mode ◽  
Expansion Valve ◽  
Valve Opening

The effects are unsatisfactory to adopt plain control mode for air-con refrigerating system with large lagging and nonlinearit features. The mechanical properties of electronic expansion valve are not sensible. In this article, BP-PID controller is adopted to control the system’s electronic expansion valve opening mechanical properties. The controller is designed. The experiment results show the controller is simple and effective, and well fulfills the users’ actual needs.

Experimental analysis of the low-GWP refrigerant R1234yf as a drop-in replacement for R134a in a typical mobile air conditioning system

2012 ◽  
Vol 226 (11) ◽  
pp. 2713-2725 ◽  
Author(s):  
Yu Zhao ◽  
Zhaogang Qi ◽  
Jiangping Chen ◽  
Baixing Xu ◽  
Bin He
Keyword(s):  
Working Conditions ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Laminated Plate ◽  
Improve Performance ◽  
Air Conditioning System ◽  
Expansion Valve ◽  
Variable Displacement ◽  
Valve Opening

This study investigated the performance of a typical mobile air conditioning system using R134a and R1234yf as the working fluids under different working conditions. The system is composed of a microchannel parallel flow condenser, a laminated plate evaporator, a variable displacement compressor, and a thermal expansion valve. The different working cycles of each refrigerant were comprehensively compared. The optimum refrigerant charge amount of the R1234yf system was approximately 95% of the R134a system during drop-in tests. The performance of the R134a system was a little higher than that of the R1234yf system. The cooling capacity and system coefficient of performance of the R134a system were 12.4% and 9% larger, respectively. This result is mainly because of the thermophysical property differences between the two refrigerants and the improper expansion valve opening of R1234yf. Analysis on the whole cycle revealed that the R1234yf system could obtain a higher evaporating pressure and a larger superheat and subcooling. Redesigning the expansion valve for R1234yf could improve performance of the system.

scholarly journals Experimental investigation of transcritical CO2 heat pump for simultaneous water cooling and heating

2010 ◽  
Vol 14 (1) ◽  
pp. 57-64 ◽  
Author(s):  
Jahar Sarkar ◽  
Souvik Bhattacharyya ◽  
Mudali Ramgopal
Keyword(s):  
Mass Flow Rate ◽  
Heat Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Water Mass ◽  
Inlet Temperature ◽  
Water Cooling ◽  
Expansion Valve ◽  
Valve Opening ◽  
Water Mass Flow Rate

This paper presents the experimental performances of a transcritical CO2 heat pump prototype for simultaneous water cooling and heating applications. System behavior and performances such as cooling capacity, heating capacity, and system coefficient of performance (COP) have been studied experimentally for various operating parameters such as water mass flow rate, water inlet temperature for both evaporator and gas cooler, and expansion valve opening. Performance is also compared with previous test data. Test indicates that the expansion valve opening has a significant effect as well near the full valve closing condition (up to 20?). Study shows that both the water mass flow rate and inlet temperature have significant effect on system performances. Test results show that, at gas cooler pressure of 90 bar, the effect of evaporator water mass flow rate on the system performances is more pronounced (COP increases 0.6 for 1 kg/min.) compared to the gas cooler water mass flow rate (COP increases 0.4 for 1 kg/min.) and the effect of gas cooler water inlet temperature is more significant (COP decreases 0.48 for given ranges) compared to the evaporator water inlet temperature (COP increases 0.43 for given ranges).

Optimization of the Water Spray Nozzle, Refrigerant Charge Amount and Expansion Valve Opening for a Unitary Ice Maker Using R-404A

2017 ◽  
Vol 25 (03) ◽  
pp. 1750025 ◽  
Author(s):  
Nae-Hyun Kim
Keyword(s):  
Ozone Depletion ◽  
Heat Transfer Performance ◽  
Condensation Temperature ◽  
Refrigeration Cycle ◽  
Evaporation And Condensation ◽  
Start Up ◽  
Expansion Valve ◽  
Valve Opening ◽  
Ice Production ◽  
Optimum Charge

R-502, which had long been used as the refrigerant of a unitary ice maker, has been replaced by R-404A due to ozone depletion. In this study, the refrigeration cycle of a unitary ice maker was optimized using R-404A. The optimization was accomplished through a search for the proper refrigerant charge amount and the opening of the expansion valve. For the present ice maker having 24 ice cups, the optimum charge amount was 580[Formula: see text]g and the optimum valve opening was “0”. At this configuration, the ice making time was 12[Formula: see text]min 55[Formula: see text]sec, ice production was 4.46[Formula: see text]kg/h and COP was 0.439. After the initial start-up period, both condensation and evaporation temperature gradually decrease with time. As ice builds up in the cup, the heat transfer performance of the evaporator decreases, which results in the decrease of the evaporation and condensation temperature. Through CFD and relevant experiments, optimum nozzle slit width and nozzle to cup distance were obtained.

scholarly journals Modelling and Simulation of a Retail Commercial Refrigeration System

2021 ◽  
pp. 1-27
Author(s):  
Oliver Brownbridge ◽  
Matthew Sully ◽  
Joshua Noons ◽  
Ibrahim Albayati
Keyword(s):  
Research Centre ◽  
Refrigeration System ◽  
Total Energy Consumption ◽  
Holistic View ◽  
Expansion Valve ◽  
Suction Line ◽  
Valve Opening ◽  
The Uk ◽  
High Level ◽  
The University

Abstract Commercial food outlets in the UK are responsible for 3% of the UK total energy consumption, with refrigeration systems account for 29% of this total. This highlights the potential and importance of huge energy saving within commercial refrigeration systems. In this paper, a validated model that simulates a commercial refrigeration system installed over 2000 sqft to mimic a real express store installed at Riseholme Refrigeration Research Centre at the University of Lincoln, UK, is developed and presented. The detailed modelling of the display case using a temperature model comprising of three states include air inside the display case, products, and the evaporator. Additionally, the model presents a holistic view of the whole system with each subsystem cohesively linked together. Further focus has been given on the high temperature (HT) system due to the high level of installations of this system found in retail commercial refrigeration stores as well as low temperature (LT) systems featuring doors which decrease the heat transfer from the store into the cases. It is concluded that the trends of the simulation results for the display case temperatures, expansion valve opening degree, suction line pressures, and compressors power consumption, all have high resemblance to the trends of collected data obtained from Riseholme Refrigeration Research Centre. This supports the validation of the developed model.

scholarly journals Effects of compressor speed and electronic expansion valve opening on the performance of R410a water chiller system

2020 ◽  
Vol 8 (1) ◽  
pp. 12-20
Author(s):  
Ahmed H. Al-Hassani ◽  
Alaa R. Al-Badri
Keyword(s):  
Electrical Energy ◽  
Cooling Capacity ◽  
System Stability ◽  
Coefficient Of Performance ◽  
Rotary Compressor ◽  
Variable Speed ◽  
Global Power ◽  
Expansion Valve ◽  
Valve Opening ◽  
Air Conditioning Systems

Refrigeration and air conditioning systems consume high rates of electrical energy of the total global power consumption. The major part of this energy is used by compressor which is the main equipment in vapor compression refrigeration systems. In this study, the performance of a variable speed chilled water refrigeration system with electronic expansion valve (EEV) is experimentally investigated. The system is composed of variable speed rotary compressor, water cooled condenser, electronic expansion valve, and evaporator with refrigerant R410a for one tone cooling capacity. The results showed that the EEV opening was related to the compressor speed at limits of refrigerant subcool and system stability to achieve better performance. Refrigerant superheats increased with closing the EEV at constant compressor speed. Moreover, the degree of superheat was inversely proportional to the compressor speed at constant EEV opening. The coefficient of performance (COP) was improved by about 2.2 to 4.0% by controlling the EEV at constant compressor speed. Increasing compressor speed from 1200 to 3600 rpm resulted in decreasing system COP from 5.2 to 2.35 due to the increase of the power consumed by compressor.

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