scholarly journals Methodology for determining of the main characteristics of a refrigeration system with condensation heat removal by radiative cooling

Author(s):  
A. P. Tsoy ◽  
A. S. Granovskiy ◽  
R. A. Jamasheva

To reduce the condensation pressure of the refrigerant in the summer, refrigeration system has been developed, in which, during periods of high air temperature, the heat of condensation is removed to the coolant, which was pre-cooled at night due to radiative cooling. A methodology has been developed for determining the main characteristics of the elements of the proposed system and calculating its daily energy consumption. The calculation shows that the proposed system with a nominal refrigerating capacity of 10 kW, using the R404a refrigerant, allows in the climate of the city of Shymkent to reduce the condensation temperature to +32.9°C, and daily energy consumption by 6.5% compared to an ordinary vapor compression refrigeration machine.

2019 ◽  
Vol 27 (04) ◽  
pp. 1950040
Author(s):  
D. Senthilkumar

This paper studies the performance of vapor compression refrigeration system using hydrocarbon refrigerant (HCR) mixture (R600a and R290), hydrocarbon nanorefrigerant mixture (R600a and R290/TiC) and cryogenically treated hydrocarbon nanorefrigerant mixture (R600a and R290/Cryo TiC). The COP of HCR (R600a and R290) system is 1.2960, whereas, COP of R600a and R290/TiC nanorefrigerant system is 1.5223. The TiC nanopowder is cryogenically treated at [Formula: see text]C for 24[Formula: see text]h. The treated TiC is dispersed in HCR mixture. Hence, the COP of R600a and R290- Cryo TiC system is further increased to 1.5801. The energy consumption of R600a and R290-TiC is reduced by 10.3% when compared with HCR. Further, it is reduced by 12.69% with respect to cryogenically treated refrigerant (R600a and R290/Cryo TiC) system. The COP is enhanced due to deep cryogenic of TiC nanopowder.


2017 ◽  
Vol 25 (01) ◽  
pp. 1750007 ◽  
Author(s):  
D. Senthilkumar

This paper deals with the influence of silicon carbide (SiC) nanopowder in R134 a refrigerant used in a vapor compression refrigeration system. The performance study was done by mixing a SiC nanopowder in R134a refrigerant. The energy consumption of the R134a refrigerant with SiC nanoparticles mixture saves 20% energy with 0.25% mass fraction of SiC nanoparticles when compared to the R134a system. The COP of the refrigerant R134a system is 1.24 whereas COP for R134a-SiC nanopowder is 1.81. The SiC nanopowder is cryogenically treated at [Formula: see text]C for 24 h and the COP is found out. The results show that the COP of R134a-SiC nanopowder and R134a-cryo SiC (cryogenically treated silicon carbide nanopowder) is increased when compared to the R134a conventional refrigeration system.


2021 ◽  
Vol 287 ◽  
pp. 03002
Author(s):  
Shuhaimi Mahadzir ◽  
Rasel Ahmed

Multistage refrigeration system plays a vital role in industrial refrigeration for the chemical, petrochemical, pharmaceuticals and food industries. Modern chemical industries are complex, and the problems are commonly multi-dimensional, non-linear and time-consuming. This study presents the application of evolutionary computation techniques, namely PSO (particle swarm optimization), GA (Genetic Algorithm) and SA (Simulated Annealing) to solve a design problem of a two-stage vapor compression refrigeration system. Two objectives are evaluated, namely the minimization of total energy consumption and maximization of the coefficient of performance (COP) of the system. The basis of design for the two-stage refrigeration system is built from and validated against data from published literature. The mass flow ratio, evaporator and condenser temperature, parameters for subcooling and desuperheating, and the coefficient of performance for the basis of design show acceptable results. The errors are below 5% against the data from published literature, which are within errors of significant figures in the calculations. In this work, the optimum solutions show a reduction of the required amount of energy consumption by 30.8% and an increase of the COP by nearly 77% with respect to the basis of design. Further improvements are made to the optimization procedures to prevent early convergence and to increase the search efficiency for finding the global optima. The findings by PSO, GA and SA are in agreement, and all evolutionary techniques achieved proper convergence of the two objective functions. It is also found that PSO requires lower computational effort, less computation time and is also easier to implement compared to GA and SA.


2021 ◽  
Vol 21 (2) ◽  
pp. 74-80
Author(s):  
Juli Mrihardjono ◽  
Didik Ariwibowo ◽  
Sutrisno Sutrisno ◽  
Dista Yoel Tadeus

Atmosphere Water Harvester (AWH) was investigated to get water collected from air in elevated performance. Improvement was performed by introducing a series-arrangement of two evaporators. Air flew through the evaporators in cross-flow. This arrangement would influence performance of the AWH system in title of COP, MHI, and specific energy consumption. The AWH was designed using vapor compression refrigeration system. Parameter measured to the system were refrigerant temperature in suction and discharge line, inlet and outlet pipe wall temperatures at evaporator and condenser, air velocity enter into evaporator, and electrical energy consumption. Instrument used in this research were refrigerant pressure-temperature gauge, K-type digital thermometer, digital fan anemometer, thermo-hygro meter, and kWh meter. Air temperature and RH data were 36,5 oC, 40%, and 19 oC, 42 %  for inlet and outlet air stram at evaporator, subsequently. With air velocity 1.5 m/s, the COP of the system was 3.7. Water collected  from AWH was 1.1 litres/hour with energy consumption of 1.24 kWh. The AWH could be considered as a water harvester with value of specific energy of 1.13 kWh/litre and MHI of 0,2.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 946
Author(s):  
Bartosz Gil ◽  
Anna Szczepanowska ◽  
Sabina Rosiek

In this work, which is related to the current European Parliament Regulation on restrictions affecting refrigeration, four new three-component refrigerants have been proposed; all were created using low Global Warming Potential(GWP) synthetic and natural refrigerants. The considered mixtures consisted of R32, R41, R161, R152a, R1234ze (E), R1234yf, R1243zf, and RE170. These mixtures were theoretically tested with a 10% step in mass fraction using a triangular design. The analysis covered two theoretical cooling cycles at evaporating temperatures of 0 and −30 °C, and a 30 °C constant condensing temperature. The final stage of the work was the determination of the best mixture compositions by thermodynamic and operational parameters. R1234yf–R152a–RE170 with a weight share of 0.1/0.5/0.4 was determined to be the optimal mixture for potentially replacing the existing refrigerants.


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