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In this century, energy saving and environmental protection are the most interesting topics in scientific technology field. One of them is heat exchangers topic. Thus, nowadays, the conventional heat exchangers have been quickly replaced by microchannels heat sinks which giving smaller size and better heat transfer behaviors. Therefore, here are much researches focus on microchannels heat sinks, especially in boiling process, as present below.
6 p hcmute 24/03/2020 305 1
Từ khóa: Heat transfer, boiling, evaporation, pure water, distilled water, microchannel.
The heat transfer characteristics of a microtube evaporator use refrigerant R134a were studied experimentally. This evaporator was made from copper tubes and aluminum foils with overall dimensions (L*W*H) of 259.3*43*200mm. The evaporator has 10 passes, each pass including 8 copper pipes (with hydraulic diameter of 0.82mm) and 83 aluminum foils (with the thickness of 0.3 mm); the distance between the two foils is 2.6 mm. The experiment was...
6 p hcmute 09/01/2020 303 2
Từ khóa: Experimental Study, Heat Transfer, R134a, MultiMicro Tubes, Evaporator.
The experiment on the fluid flow characteristics of R134a in an evaporator with horizontal microtube was performed. In this study, the air volume flow rate and the ambient temperature has changed from 19 to 47.5 l/s and 26 to 32 0C, respectively. Besides, a comparison between the micro evaporator and the macro evaporator (FNA) was also conducted. The pressure drop of the macro evaporator is lower than that obtained from the micro evaporator....
7 p hcmute 09/01/2020 308 2
Từ khóa: Microtube; micro evaporator; R134a; fluid flow; microchannel.
The heat transfer characteristics of a microtube evaporator use refrigerant R134a were studied experimentally. This evaporator was made from copper tubes and aluminum foils with overall dimensions (L*W*H) of 259.3*43*200mm. The evaporator has 10 passes, each pass including 8 copper pipes (with hydraulic diameter of 0.82mm) and 83 aluminum foils (with the thickness of 0.3 mm); the distance between the two foils is 2.6 mm
8 p hcmute 23/05/2019 333 2
Từ khóa: Experimental Study, Heat Transfer, R134a, MultiMicro Tubes, Evaporator.
Experimental study on the pressure and the power input of a CO air conditioning system
The environmentally friendly refrigerants and high effectiveness heat exchangers are interesting topics for scientists. For natural refrigerants, the carbon dioxide (R744-CO ) is considered as a good candidate in order to replace HCFC (Hydrochlofluorocarbon) or HFC (Hydrofluorocarbon). Besides, the compact heat exchangers with high heat transfer efficiency would be used widely in the future
12 p hcmute 23/05/2019 370 2
Từ khóa: Air conditioning, CO2 refrigerant, pressure, power input, evaporator, heat transfer
Experiments on Expansion and Superheat Processes of a Co 2 Cycle Using Microchannel Evaporator
Experiments on expansion and superheat processes of a transcritical CO2 air conditioning system were done. In this study, the cross-sectional area of the expansion valve reduces from 8.195 to 0.091mm2, the cooler pressure increases and the evaporator pressure decreases; the pressure difference between cooler and evaporator increases. Besides, the power input of compressor increases as decreasing the crosssectional area.It is also observed that...
25 p hcmute 01/06/2018 539 2
Từ khóa: Experiment, CO 2 refrigerant, expansion, superheat, evaporator, microchannel
An Experiment on a CO Air Conditioning System with Copper Heat Exchangers 2
This paper presented an experiment on a CO air conditioning system with copper heat exchangers. In this study, the compressor and cooler were tested with hydraulic method to determine the deformed and torn temperatures. The results show that conventional compressor is not suitable for using high pressure, due to the COP of cycle is very low (0.5 only). With CO2 compressor, the cycle can achieved COP of 3.07 at the evaporative temperature of...
7 p hcmute 01/06/2018 493 2
Từ khóa: air conditioning system, heat exchanger, cooler, evaporator, CO refrigerant. 2
The investigation presented a numerical simulation on heat transfer behaviors in microchannel evaporator of a CO air conditioning system. The conditions for numerical simulation were applied by the experimental data of a CO 2 air conditioning cycle. This cycle worked with the cooler pressure of 85 bar, evaporator pressure of 37 bar, and the CO 2 flow rate of 5.2 g/s. The temperature and pressure in microchannels are uniform; they are suitable...
8 p hcmute 01/06/2018 424 1
Từ khóa: Numerical simulation, CO refrigerant, air conditioning system, heat transfer, evaporator
Experiments on expansion and superheat processes of a CO2 cycle using microchannel evaporator
Experiments on expansion and superheat processes of a transcritical CO2 air conditioning system were done. In this study, the cross-sectional area of the expansion valve reduces from 8.195 to 0.091 mm2, the cooler pressure increases and the evaporator pressure decreases; the pressure difference between cooler and evaporator increases
25 p hcmute 16/05/2018 402 1
Từ khóa: Experiment, CO refrigerant, expansion, superheat, evaporator, microchannel
An experiment on a co2 air conditioning system with copper heat exchangers
This paper presented an experiment on a CO2 air conditioning system with copper heat exchangers. In this study, the compressor and cooler were tested with hydraulic method to determine the deformed and torn temperatures. The results show that conventional compressor is not suitable for using high pressure, due to the COP of cycle is very low (0.5 only). With CO2 compressor, the cycle can achieved COP of 3.07 at the evaporative temperature of...
7 p hcmute 16/05/2018 447 1
Từ khóa: air conditioning system, heat exchanger, cooler, evaporator, CO2 refrigerant.
The investigation presented a numerical simulation on heat transfer behaviors in microchannel evaporator of a CO2 air conditioning system. The conditions for numerical simulation were applied by the experimental data of a CO2 air conditioning cycle. This cycle worked with the cooler pressure of 85 bar, evaporator pressure of 37 bar, and the CO2 flow rate of 5.2 g/s.
8 p hcmute 16/05/2018 508 1
Từ khóa: Numerical simulation, CO refrigerant, air conditioning system, heat transfer, evaporator
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