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Journal articles on the topic 'Refrigerant circulation'

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Author: Grafiati
Published: 30 May 2022
Last updated: 31 May 2022

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1

Hamad, Ahmed J. "Experimental Investigation of Vapor Compression Refrigeration System Performance Using Nano-Refrigerant." Wasit Journal of Engineering Sciences 2, no. 2 (October 2, 2014): 12–27. http://dx.doi.org/10.31185/ejuow.vol2.iss2.26.

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Experimental investigation of vapor compression refrigeration system performance using Nano-refrigerant is presented in this work. Nano-refrigerant was prepared in current work by mixing 50 nanometers diameter of copper oxide CuO nanoparticles with Polyolester lubrication oil and added to the compressor of the refrigeration system to be mixed with pure refrigerant R-134a during its circulation through refrigeration system. Three concentrations (0.1%, 0.25%, and 0.4%) of CuO-R134 a Nano-refrigerant are used to study the performance of the refrigeration system test rig and to investigate the effect of using Nano-refrigerant as a working fluid compared with pure refrigerant R-134a. The results showed that, the increasing in concentration of CuO nanoparticles in the Nano-refrigerant will significantly enhance the performance of the refrigeration system, as adding nanoparticles will increase the thermal conductivity, heat transfer and improve the thermo-physical properties of Nano-refrigerant. Investigation of performance parameters for refrigeration system using Nano-refrigerant with 0.4% concentration compared with that for pure refrigerant R-134a shows that, Nano-refrigerant has reflect higher performance in range of 10% and 1.5% increase in COP and refrigeration effect respectively and 7% reduction in power consumption for refrigeration system. It can be concluded that, Nano-refrigerants can be efficiently and economically feasible to be used in the vapor compression refrigeration systems.
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2

OKAMOTO, Yoshiyuki, Masahiko SUZUKI, Kiyoshi KAWAGUCHI, and Kouji KISHITA. "Boiling Refrigerant Type Panel Cooler. Refrigerant Circulation and Cooling Performance." Transactions of the Japan Society of Mechanical Engineers Series B 66, no. 645 (2000): 1447–52. http://dx.doi.org/10.1299/kikaib.66.1447.

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3

Okamoto, Yoshiyuki, Masahiko Suzuki, Kiyoshi Kawaguchi, and Kouji Kishita. "Boiling refrigerant-type panel cooler (refrigerant circulation and cooling performance)." Heat Transfer?Asian Research 33, no. 2 (2004): 94–105. http://dx.doi.org/10.1002/htj.20003.

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4

Jiang, Wei Jiang. "The Study of Heat-Engines Based on Refrigerant Phase-Change Circulation." Applied Mechanics and Materials 66-68 (July 2011): 649–53. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.649.

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This paper firstly introduces the principles of Stirling heat engines based on refrigerant phase-change circulation. This heat engines use two external heat reservoire. When the refrigerant in an engine cylinder absorbs heat from high-temperature heat sources, refrigerant is transformed from liquid to gas and the volume of the refrigerant expands to drive the piston apply work. When the refrigerant releases heat to low-temperature sources, the volume of the refrigerant shrinks. Therefore, phase change thermal engine technology using solar energy, industrial waste heat and heat produced by combustion of any fuel to work, no gas emissions, high thermal efficiency and environmental advantages. Thermal phase transition and thus the engine technology will be in the field of energy and power of a cutting-edge technology, great development potential and prospects.
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5

Chen, J., and H. Kruse. "Calculating Circulation Concentration of Zeotropic Refrigerant Mixtures." HVAC&R Research 1, no. 3 (July 1, 1995): 219–31. http://dx.doi.org/10.1080/10789669.1995.10391320.

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6

Xie, Y., S. Nagai, T. Okamura, and N. Hirano. "Refrigerant circulation system for cooling a HTS coil." Journal of Physics: Conference Series 1559 (June 2020): 012094. http://dx.doi.org/10.1088/1742-6596/1559/1/012094.

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7

Sologubenko, O., J. Hemrle, and L. Kaufmann. "Passive system of cooling and refrigerant fluid circulation, assisted by capillary pumping." Journal of Physics: Conference Series 2116, no. 1 (November 1, 2021): 012092. http://dx.doi.org/10.1088/1742-6596/2116/1/012092.

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Abstract We propose a concept design of a cooling system, primarily targeting gas-insulated switchgear enclosures which use a mixture of a refrigerant fluid, such as Novec™ 649, and a non-condensable gas for electrical insulation. The novel open-loop system relies on evaporative cooling assisted by capillary pumping, and refrigerant vapor condensation on the walls of the system enclosure. The results of experiments on a laboratory prototype are presented and discussed. Besides cooling, a major benefit of the system is in facilitating the circulation of the gas mixture in the enclosure.
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8

Tsoy, Alexandr, Alexandr Granovskiy, Diana Tsoy, and Dmitriy Koretskiy. "Cooling capacity of experimental system with natural refrigerant circulation and condenser radiative cooling." Eastern-European Journal of Enterprise Technologies 2, no. 8 (116) (April 30, 2022): 45–53. http://dx.doi.org/10.15587/1729-4061.2022.253651.

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The surface of the Earth is a source of radiation of thermal energy, which, passing through the atmosphere, is partially absorbed while the bulk of the energy is released into the surrounding outer space. A cooling technique based on this physical phenomenon is known as radiative cooling (RC). It is possible to reduce the consumption of electricity for cooling, as well as to reduce capital costs, by integrating the unit with radiative cooling directly into the circulation circuit of the refrigerant of the refrigeration machine. An experimental refrigeration system has been designed, in which in the cold periods of the year the removal of heat from the cooled object is carried out due to the mode of natural circulation of the refrigerant from the evaporator to the heat exchanger, cooled by radiative cooling. A refrigeration system with natural circulation and radiative cooling of the refrigerant R134a was experimentally studied during the autumn period in Almaty. The experimental study established that the chamber is cooled with the help of the examined system while the temperature in the cooled volume is maintained by 5...7 K above ambient air temperature at night. The dependence of the air temperature in the refrigerating chamber on the temperature of the atmospheric air has been determined. A procedure for assessing the cooling capacity of the system has been devised. The study reported here demonstrated the possibility of using radiative cooling to remove heat under the mode of natural circulation of the refrigerant. The refrigeration system reduces energy consumption in the cold seasons by diverting heat to the environment without the compressor operating
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9

Lee, Seok-Ju, Hae-Jin Sung, Minwon Park, DuYean Won, Jaeun Yoo, and Hyung Suk Yang. "Analysis of the Temperature Characteristics of Three-Phase Coaxial Superconducting Power Cable according to a Liquid Nitrogen Circulation Method for Real-Grid Application in Korea." Energies 12, no. 9 (May 8, 2019): 1740. http://dx.doi.org/10.3390/en12091740.

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Large-capacity superconducting power cables are in the spotlight to replace existing underground transmission power cables for energy power transmission. Among them, the three-phase coaxial superconducting power cable has the economic advantage of reducing the superconducting shielding layer by enabling magnetic shielding when the three phases are homogeneous without an independent superconducting shielding layer for magnetic shielding. In order to develop the three-phase coaxial superconducting power cable, the electrical and structural design should be carried out to construct the superconducting layer. However, the thermal design and analysis for the cooling of the three-phase coaxial superconducting power cable must be done first, so that the electrical design can be made using the temperature transferred to the superconducting layer. The three-phase coaxial superconducting cable requires a cooling system to circulate the cryogenic refrigerant for cooling below a certain temperature, and the structure of the cable through which the cryogenic refrigerant travels must also be analyzed. In this paper, the authors conducted a longitudinal temperature analysis according to the structure of the refrigerant circulation system of the cable and proposed a refrigerant circulation system suitable for this development. The temperature profile according to this analysis was then used as a function of temperature for the electrical (superconducting and insulating layers) design of the three-phase coaxial superconducting power cable. It is also expected to be used to analyze the cooling structure of the three-phase coaxial superconducting power cable installed in the real grid system.
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10

Sun, Liying, and Liang Liu. "Establishment and solution of the RNC flow network model." International Journal of Modeling, Simulation, and Scientific Computing 05, no. 04 (September 29, 2014): 1471001. http://dx.doi.org/10.1142/s1793962314710019.

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Refrigerant natural circulation (RNC) system is a closed loop recycling system which is composed of evaporator, condenser, gas pipe and the liquid pipe. The difference in indoor and outdoor temperatures will lead to the refrigerant phase-change, and the gravity difference caused by different heights of condenser and evaporator will make the low boiling point refrigerants carry on natural circulation to realize the indoor heating or cooling. In order to analyze the effect of changes in the RNC system upon the working conditions of the indoor and outdoor units as well as the function of the indoor unit, this paper describes the incidence relations among the various components of the RNC system, and establishes gas–liquid two-phase fluid network mathematical model by using the method of fluid network; besides utilizing the model, it also conducts simulator investigation of coupling characteristics of the RNC system's refrigeration condition, and makes an analysis of indoor temperature, indoor unit's air volume, the number of indoor units and the indoor unit capacity and other factors' changes on the coupling characteristics of the RNC system. The results show that under refrigeration conditions, the increase in the air volume of a single indoor unit or room temperature will result in an increase in the cooling capacity of its own indoor units, a decrease in the cooling capacity of other indoor units and a reduction in the total cooling capacity of indoor units of the RNC system; however, the decrease in the outdoor units' inlet temperature will lead to a drop in the evaporation temperature of the system and increase in the cooling capacity.
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11

Lin, Bichao, Jiwen Cen, and Fangming Jiang. "Thermal Performance of a Cylindrical Lithium-Ion Battery Module Cooled by Two-Phase Refrigerant Circulation." Energies 14, no. 23 (December 3, 2021): 8094. http://dx.doi.org/10.3390/en14238094.

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It is important for the safety and good performance of a Li-ion battery module/pack to have an efficient thermal management system. In this paper, a battery thermal management system with a two-phase refrigerant circulated by a pump was developed. A battery module consisting of 240 18650-type Li-ion batteries was fabricated based on a finned-tube heat-exchanger structure. This structural design offers the potential to reduce the weight of the battery thermal management system. The cooling performance of the battery module was experimentally studied under different charge/discharge C-rates and with different refrigerant circulation pump operation frequencies. The results demonstrated the effectiveness of the cooling system. It was found that the refrigerant-based battery thermal management system could maintain the battery module maximum temperature under 38 °C and the temperature non-uniformity within 2.5 °C for the various operation conditions considered. The experimental results with 0.5 C charging and a US06 drive cycle showed that the thermal management system could reduce the maximum temperature difference in the battery module from an initial value of 4.5 °C to 2.6 °C, and from the initial 1.3 °C to 1.1 °C, respectively. In addition, the variable pump frequency mode was found to be effective at controlling the battery module, functioning at a desirable constant temperature and at the same time minimizing the pump work consumption.
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12

Zhang, Hui, Wen Dong Xu, Yun Long Teng, and Cheng Ming An. "Development and Engineering Design of Technology for Utilization of Liquefied Natural Gas (LNG) Cold Energy in Ice-Making." Advanced Materials Research 805-806 (September 2013): 519–25. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.519.

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A process of using LNG cold energy for ice-making was proposed, the process consisted of three parts: LNG vaporization system, the refrigerant circulation system and ice-making system. And LNG cold energy was delivered to ice-maker by refrigerant. Through design and optimization, the optimum temperature was confirmed in the ice-making process, the benefit of power saving was calculated, and the efficiency of energy utilization was analyzed by exergy analysis method. The research results showed that the average ice quantity was 1.59t/h with vaporization amount of 1000kg/h LNG. Taking ethylene glycol aqueous solution as refrigerant, when its temperature changed from-15°C to-6°C, the energy efficiency was higher with 18°C temperature difference. And the benefit of electricity saving was 112 kW and the efficiency of cold exergy was 5.52%. The process can be designed into skid-mounted, which can flexibly operate between different LNG vaporization stations.
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13

OKAJIMA, Junnosuke, Atsuki KOMIYA, and Shigenao MARUYAMA. "J024023 Control of frozen region by ultrafine cryoprobe utilizing refrigerant circulation system." Proceedings of Mechanical Engineering Congress, Japan 2011 (2011): _J024023–1—_J024023–4. http://dx.doi.org/10.1299/jsmemecj.2011._j024023-1.

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14

Pan, Cheng Jun, and Yi Da Tang. "Effect of Condenser Temperature and Speed on one A/C System." Advanced Materials Research 314-316 (August 2011): 686–90. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.686.

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This study describes the results on the performance of one vehicle air conditioning system. The coefficient of performance, evaporator cooling capacity, compressor power consumption, total mass flow rate, vapor mass flow rate, liquid mass flow rate and oil in circulation, pressures and temperatures of refrigerant at every component (inlets and outlets) are measured and analyzed with the variation of the outside temperatures at the evaporator and condenser, the speed of the compressor, refrigerant charge and oil charge. The systematical experimental results obtained from this real-size test system depict the relations between the above parameters in a vehicle air conditioning system, which constitute a useful source for vehicle air conditioning systems design and analysis. The vapor quality (two-phase flow) measurements realized in this work provide an extremely important tool for diagnosing the system performances.
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15

Pan, Cheng Jun, and Yi Da Tang. "Effect of Refrigerant Charge and Inlet Air Temperature on One A/C System." Applied Mechanics and Materials 71-78 (July 2011): 2142–46. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.2142.

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This study describes the results on the performance of one vehicle air conditioning system. The coefficient of performance, evaporator cooling capacity, compressor power consumption, total mass flow rate, vapor mass flow rate, liquid mass flow rate and oil in circulation, pressures and temperatures of refrigerant at every component (inlets and outlets) are measured and analyzed with the variation of the outside temperatures at the evaporator and condenser, the speed of the compressor, refrigerant charge and oil charge. The systematical experimental results obtained from this real-size test system depict the relations between the above parameters in a vehicle air conditioning system, which constitute a useful source for vehicle air conditioning systems design and analysis. The vapor quality (two-phase flow) measurements realized in this work provide an extremely important tool for diagnosing the system performances.
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16

Yu, Xin Qi, Zhi Xu, Qing Gang Liu, Dong Dong Yuan, and Jia Hui Yu. "Application of Cold Water Cycle for Indoor Cooling System." Advanced Materials Research 953-954 (June 2014): 809–12. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.809.

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A small indoor cooling system through cold water circulation is introduced in this paper. The system mainly includes cooling pool, cold water circulation equipment, indoor heat exchanger, temperature measurement equipment and induction controlling equipment. The indoor cooling is achieved by heat transfer between the natural underground water of lower temperature and indoor air of higher temperature, and it is different from the traditional compression refrigeration system in which a great amount of electric energy is consumed while the refrigerant is compressed. Compared with the ordinary air conditioning system, this system has obvious advantages on economy, application potential and energy conservation in rural developing areas.
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17

Suzuki, Masahiko, Kiyoshi Kawaguchi, Takahide Ohara, and Hiroyuki Osakabe. "Compact thermosyphon using multistacked radiator cores for automobiles: Refrigerant circulation and cooling performance." Heat Transfer?Asian Research 29, no. 3 (May 2000): 204–17. http://dx.doi.org/10.1002/(sici)1523-1496(200005)29:3<204::aid-htj5>3.0.co;2-m.

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18

LI, K. N., M. W. TONG, and K. LIN. "EXPERIMENTAL RESEARCH ON THE INFLUENCE OF JET PUMP ON THE COOLING STORAGE PROPERTY OF GAS HYDRATES." International Journal of Modern Physics B 19, no. 01n03 (January 30, 2005): 507–9. http://dx.doi.org/10.1142/s021797920502892x.

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In this experimental research, jet pump is added to the cooling storage circulation of gas hydrates for the first time. The research result shows that: jet pump strengthened the mixture of water and refrigerant and formed the hydrate nucleus in jet pump. Compared with the circling without jet, the sub-cooled nucleation temperature reduced 2~4°C, the mixture time of hydrates shortened 13%~25% in the experimental parameter. There is a best jet proportion, which is about 0.4.
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19

KASHIWAGI, Takao, Koji OMATA, Yoshikazu NAGAOKA, Kikutaro FUJIKURA, and Noriyuki NISHIYAMA. "High-performance absorption cycle with the circulation of auxiliary refrigerant. 1st report, Cycle Simulation." Transactions of the Japan Society of Mechanical Engineers Series B 56, no. 530 (1990): 3018–25. http://dx.doi.org/10.1299/kikaib.56.3018.

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20

SUZUKI, Masahiko, Kiyoshi KAWAGUCHI, Takahide OHARA, and Hiroyuki OSAKABE. "Cmopact Thermosyphon using Multi-stacked Radiator Cores for Automobile. Refrigerant Circulation and Cooling Performance." Transactions of the Japan Society of Mechanical Engineers Series B 64, no. 622 (1998): 1861–66. http://dx.doi.org/10.1299/kikaib.64.1861.

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21

Gorelik, J. B., A. K. Khabitov, and I. V. Zemerov. "EFFICIENCY OF SURFACE COOLING OF FROZEN SOIL FOUNDATION USING A FORCED REFRIGERANT CIRCULATION UNIT." Криосфера Земли 25, no. 4 (2021): 36–46. http://dx.doi.org/10.15372/kz20210404.

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22

Sreenivas, Bura, H. Gurudath Nayak, and G. Venkatarathnam. "Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode." Cryogenics 81 (January 2017): 42–46. http://dx.doi.org/10.1016/j.cryogenics.2016.11.007.

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23

Xiong, Liu. "Study on the Hybrid Liquid Desiccant Evaporative Cooling Air-Conditioning Refrigeration Circulation System." Advanced Materials Research 516-517 (May 2012): 1250–56. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1250.

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This article presents a new hybrid evaporative cooling air-conditioning refrigeration system using two-stage liquid desiccant, and carries off the theoretical study on it. Compared with the conventional liquid desiccant air-conditioning refrigeration system, the new system adopts direct mixing heat transfer technology and evaporative cooling technology instead of water-cooled or air-cooled technology. Thus the cooling water usage is reduced. Using the two-stage adiabatic absorber and using refrigerant rather than water as the cooling medium of desiccant solution, the pressure difference of mass transfer is increased. Compared with the conventional system, the heat of regenerating solution is decreased because the mass ratio of air to desiccant solution is increased which gives rise to the decline of solution's mass rate. The results of theoretical calculation show that the new system has the better performance in power consumption, usage of water and equivalent coefficient of performance than the conventional system.
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24

NAGAOKA, Yoshikazu, Kikutaro FUJIKURA, Noriyuki NISHIYAMA, Takao KASHIWAGI, and Koji OMATA. "High-performance absorption cycle with the circulation of auxiliary refrigerant. 2nd reoprt, Experiments and characteristic analysis." Transactions of the Japan Society of Mechanical Engineers Series B 56, no. 530 (1990): 3026–33. http://dx.doi.org/10.1299/kikaib.56.3026.

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25

Sun, Li Ying, Li Tao Xiao, and Yi Tong Li. "Experimental Study on Heat Pipe Heat Recovery Type of Fresh Air Ventilator." Advanced Materials Research 608-609 (December 2012): 1172–76. http://dx.doi.org/10.4028/www.scientific.net/amr.608-609.1172.

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Have proposed a heat recovery of fresh air ventilator system form,which is based on the technology of refrigerant natural circulation named heat-pipe. Describes the working principle of the unit, designs a new type of heat recovery air ventilator test equipment,and carries out a experimental study on its running performance.Have come to the effect of air flow and the temperature difference between indoor and outdoor for the heat recovery rate. Experimental results show that this equipment has a high heat recovery efficiency and a good effect on energy-saving . Through experimenting on the performance, laying a foundation for further optimization of unit design.
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26

Obstawski, Paweł, Tomasz Bakoń, and Anna Kozikowska. "Influence of circulating pump efficiency on the heat exchange process in a plate heat exchanger used in a solar heating installation." E3S Web of Conferences 154 (2020): 05008. http://dx.doi.org/10.1051/e3sconf/202015405008.

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In solar heating systems with an absorber area of more than 20 m2, a plate heat exchanger is used as a separator between the primary glycol-based refrigerant and secondary water. The use of a plate heat exchanger enables an increase in the heat exchange area compared to the standard coil heat exchangers located inside the domestic hot water tank. An important problem is to determine the volume flow rate on both the primary and secondary side of the exchanger. The paper presents an analysis of the influence of the circulation pump efficiency on the primary and secondary side of the heat exchanger installed in a solar heating installation on the intensity of the heat exchange process.
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27

UTAKA, Yoshio, Akio SAITO, and Takashi SEKI. "Cool Energy Storage of Gas Hydrate Using Natural Circulation of Refrigerant with Direct Contact Boiling and Condensation." Transactions of the Japan Society of Mechanical Engineers Series B 57, no. 543 (1991): 3911–15. http://dx.doi.org/10.1299/kikaib.57.3911.

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28

GOTO, Makoto, Koji TANIFUJI, Masahiro FUJITA, Tomohiro YAMAUCHI, Satoshi OHUCHIDA, Kenji NAGATA, Isao UENO, and Tatsuya HASEGAWA. "Observation of Circulation of Immiscible Mineral Lubricant Oil in an Air-Conditioning Machine Charged with HFC Refrigerant." Journal of Environment and Engineering 4, no. 1 (2009): 47–56. http://dx.doi.org/10.1299/jee.4.47.

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29

GOTO, Makoto, Koji TANIFUJI, Masahiro FUJITA, Tomohiro YAMAUCHI, Satoshi OHUCHIDA, Kenji NAGATA, Isao UENO, and Tatsuya HASEGAWA. "Observation of Circulation of Immiscible Mineral Lubricant Oil in an Air Conditioning Machine Charged with HFC Refrigerant." Transactions of the Japan Society of Mechanical Engineers Series B 73, no. 725 (2007): 291–97. http://dx.doi.org/10.1299/kikaib.73.291.

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30

Kadhim, Mustafa Mohammed. "Manufacturing a Refrigerator with Heat Recovery Unit." Journal of University of Babylon for Engineering Sciences 26, no. 4 (February 18, 2018): 104–23. http://dx.doi.org/10.29196/jub.v26i4.788.

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This study aims to exploite the rejected heating energy from condenser and benefit from it to reheat the foods and other materials. It can also be employed to improve the coefficient of performance of a refrigerator at the same time by using approximately the same consumption electrical energy used to operate the compressor and refrigerator in general. This idea has been implemented by manufacturing of a refrigerator with using additional part has the same metal and condenser pipe diameters but its surface area does not exceed 40% from total surface area of the condenser and its design as an insulated cabinet from all sides to prevent heat leakage through it and located between the compressor and the condenser. Small electrical fan has been added inside this cabinet to provide a suitable air circulation and a homogenous temperature distribution inside the cabinet space. It is expected that the super heating energy of refrigerant (R134a) which comes out of the compressor would be removed inside this cabinet and this insist to condensate the refrigerant (cooling fluid) with a rate higher than that used in the normal refrigerator only. Three magnetic valves have been used in order to control the refrigerant flow in state of operation the refrigerator only or to gather with heating cabinet. To measure the temperatures at each process of the simple vapor compression refrigeration cycle, nine temperature sensors at input and output of each compressor, condenser and an evaporator in additional to input of cabinet and inside it and on evaporator surface have been provided. Five pressure gages have been used to measure the value of pressure and compare it for the two states of operation. The consumption of electrical energy can be calculated by adding an ammeter and a voltmeter and compare between the consumption energy of both states. The obtained results show that there is an improvement in the coeffecient of performance in state of operation the refrigerator with heat recovery cabinet by 20% more than that of the operation of refrigerator only. This improvement is due to the reduction in the condenser exit temperature by 4 to 6 C˚, and the super heat removing process in reheating cabinet. The temperature of the cabinet reachs to 60 C˚ which is a sufficient for the food heating. A small amount of refrigerant pressure reduction due to these additions, and its effect on the preformace of the refrigerator may be not considerable.
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31

Xiao, Lu, and Jinhua Chen. "Experimental Study on Distillation Column Parameters for Liquefaction Device of Low Concentration Coalbed Methane." Processes 9, no. 4 (March 30, 2021): 606. http://dx.doi.org/10.3390/pr9040606.

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The input-output ratio and comprehensive energy consumption of low concentration coalbed methane cryogenic liquefaction devices are determined by the process parameters in control of the distillation column. In order to accurately control the actual operation process of the distillation column, the effect of the operating temperature of the distillation column on the liquefaction performance of a cold box was studied experimentally, and the optimal control parameters of the distillation column were obtained. The results show that the recovery rate of methane decreases with the increase in temperature at the top of the distillation column, and when this temperature is higher than −178 °C, the methane recovery rate drops sharply to below 90%. When the temperature at the bottom of the distillation column rises from −154 °C to −142.7 °C, the purity of LNG products is improved, and when this temperature is increased to −143.5 °C, the purity of products at the bottom of the distillation column reaches the standard, and can be stored safely. In actual operation, the evaporation temperature at the bottom of the column should not be higher than −140 °C. In the process of industrial plant design, measures should be taken to reduce the interaction of the temperature regulation at the top and bottom of the distillation column. When selecting the refrigerant circulation compressor, the leakage of the refrigerant should be considered to maintain the operating pressure of the refrigeration cycle.
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32

SYED ABDUL HAMEED, SYED DANISH, and D. C. VISHWAKARMA. "Performance Enhancement techniques in vapour Compression refrigeration system by various evaporator loads and thermoelectric sub cooling." Journal of Ultra Scientist of Physical Sciences Section B 32, no. 4 (October 19, 2020): 21–30. http://dx.doi.org/10.22147/jusps-b/320401.

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Part load performance analysis on simple VCR system using selected refrigerant mixture at different loading conditions is completed to identify the economic mode of loading in the evaporator. In this research work, evaporator has been loaded at different loading (thermal loading – cooling of liquid substance in the evaporator) conditions like 25, 50, 75 and 100% of its capacity based on its volume and water is considered as a substance to be cooled in the evaporator for analyzing the performance of the refrigeration system at different loading conditions. The cooling temperature C and the condensation process has range of water is considered from 26 to 2 been carried out by Atmospheric Air Circulation (AAC) mode. The various performance indexes of refrigeration systems namely work input to the compressor, condenser heat rejection rate, refrigerating effect and COP are obtained based on unit mass flow rate of the refrigerant in this analysis. Experimental results. Experimental analysis has been carried out with 3oC of subcooling in the VCR system with thermoelectric subcooling and various performance indexes are investigated with reference to water temperature in the evaporator at different loading conditions. Significant improvements in various performance indexes have been obtained for VCR system with thermoelectric subcooling. The experimental results clearly state that 75% loading condition gives the highest COP at lowest temperature of evaporator substance. Among various loading conditions, COP of 75% loading condition is about 6.7, 3.9 and 25.13% higher than that of 25, 50 and 100% loading conditions respectively. suggest that 75% loading condition is the significant one among other loading conditions in the evaporator.
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33

Belyaev, Aleksey, Georgiy Prokhorov, and Anna Arkhitskaya. "CRYOSURGERY IN THE TREATMENT OF PATIENTS WITH BONE TUMORS." Problems in oncology 65, no. 2 (February 1, 2019): 165–71. http://dx.doi.org/10.37469/0507-3758-2019-65-2-165-171.

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A review of the literature shows that surgical procedures will remain the standard treatment for primary bone tumors. Analysis of studies on the assessment of long-term results shows that additional double cryogenic treatment of the curettage cavity can improve the treatment outcomes of patients with giant cell tumors, dysplastic diseases and some forms of malignant lesions. The traditional execution of the procedure is associated with the open installation of liquid nitrogen in the bone cavity, which requires special skills in handling aggressive refrigerant from the staff and does not exclude complications. In case of multiple metastatic bone lesions, surgical treatment is not indicated. The recent emergence in clinical practice of new equipment with a closed liquid nitrogen circulation circuit inside cryoprobes resumes interest in cryoabla-tion of bone tumor lesions using modern minimally invasive puncture cryotechnology and expanding indications for its use in patients with severe comorbidities.
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34

Okazaki, Yodai, Masazumi Noguchi, Takumi Takazawa, Tetsuji Okamura, and Naoki Hirano. "Research of Combined Use of Magnetic Refrigeration Technology With a Refrigerant Circulation System for Cooling a High Temperature Superconducting Coil." IEEE Transactions on Applied Superconductivity 32, no. 6 (September 2022): 1–5. http://dx.doi.org/10.1109/tasc.2022.3155516.

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Siregar, Devi Marietta, Yiseul Park, Yong Sun Won, and Jun Heok Lim. "Removal of HFC-134a from Brackish Water Using a Semi Batch Jet Loop Reactor." Energies 12, no. 2 (January 19, 2019): 311. http://dx.doi.org/10.3390/en12020311.

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Mineral salt components (Na+, Ca2+, K+, Mg2+, etc.) are naturally excluded during the gas hydrate in which water molecules form cavities by hydrogen bonding and guest gas molecules are encapsulated into the cavities to stabilize the overall gas hydrate structure. However, when using refrigerant hydrofluorocarbon-134a (HFC-134a) for guest gas, it resided in resulting brackish water after the desalination process because of its high solubility in water. Jet loop reactors (JLRs) are frequently employed in many commercial applications because of their high mass transfer capabilities. In this study, a semi-batch type JLR was introduced to improve the degassing of HFC-134a from brackish water. The effect of parameters, such as the initial HFC-134a concentration (200–772 mg/L), liquid circulation (40–80 L/min) rate, and air flow rate (10–30 L/min), were studied in this JLR. The removal efficiency and overall volumetric transfer were calculated and it was determined that increasing the air flow rate has a high effect on KLa.
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Коновалов, Дмитро Вікторович, Роман Миколайович Радченко, Сергій Георгійович Фордуй, Віктор Павлович Халдобін, Олексій Олегович Зєліков, and Олександр Анатолійович Різун. "ВДОСКОНАЛЕННЯ ТЕПЛОВИКОРИСТОВУЮЧИХ ЕЖЕКТОРНИХ ХОЛОДИЛЬНИХ МАШИН ЗАСТОСУВАННЯМ АЕРОТЕРМОПРЕСОРНИХ ТЕХНОЛОГІЙ." Aerospace technic and technology, no. 1 (February 26, 2021): 60–66. http://dx.doi.org/10.32620/aktt.2021.1.06.

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The paper shows and analyzes circuit solutions for improving the existing schemes of ejector heat-using refrigeration machines, which are used as part of cogeneration plants. One of the promising areas is the use of an aerothermopressor, which implements the effect of thermogasdynamic compression, which is to increase the pressure while reducing the temperature in the evaporation of liquid, which injected into the flow of vapor moving at speed near the sound. To analyze the efficiency of ejector refrigeration machines, the developed calculation model was used, which takes into account the use of an aerothermopressor in the cycles of refrigeration machines with the features of the calculations of cycles and circuits. To select and determine possible circuit solutions, the efficiency of an aerothermopressor for different refrigerants was evaluated and a comparative analysis of the characteristic parameters of the efficiency of an aerothermopressor in the range of cooling temperature differences is 20–100 oC was made. It is possible to increase the efficiency of ejector heat-using refrigeration machines when using an aerothermopressor by providing a temperature difference of 60–100 oC. The analysis showed that the most important are: R717, R134a, R227ea, R1234ze (E), R1234yf (2–4%). It is possible to provide a higher thermal coefficient for ejector heat-using refrigeration machines by using an aerothermopressor in the circuit using the circulation of liquid refrigerant. The corresponding increase in the thermal coefficient is 1.5–2.0%. The use of an aerothermopressor in the scheme with heat recovery allows removing additional overheating of vapor before suctioning into the ejector with a corresponding increase in the thermal coefficient by 4-8%. The analysis shows that the total increase in the thermal coefficient due to the combined use of an aerothermopressor, heat recovery, and recirculation is 10–15% at a base value of 0.30–0.40.
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Navarro, E., J. F. Urchueguía, J. Gonzálvez, and J. M. Corberán. "Test results of performance and oil circulation rate of commercial reciprocating compressors of different capacities working with propane (R290) as refrigerant." International Journal of Refrigeration 28, no. 6 (September 2005): 881–88. http://dx.doi.org/10.1016/j.ijrefrig.2005.01.010.

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38

UDAGAWA, Yosuke, Keisuke SEKIGUCHI, and Masahide YANAGI. "435 Development of an Packaged Air Conditioner for Data Centers with Outdoor Air Cooling : Verification about the amount of refrigerant circulation." Proceedings of the Symposium on Environmental Engineering 2013.23 (2013): 384–85. http://dx.doi.org/10.1299/jsmeenv.2013.23.384.

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39

Utaka, Yoshio, Akio Saito, and Takashi Seki. "Gas Hydrate Cold Storage Using Direct-Contact Heat Transfer of Liquid-Vapor Phase Change and Natural Circulation of Refrigerant in Closed Vessel." JSME International Journal Series B 36, no. 1 (1993): 150–55. http://dx.doi.org/10.1299/jsmeb.36.150.

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40

Korotkiy, Igor, Evgeniy Neverov, Ludmila Lifentseva, and Alexandr Raschepkin. "Analysis of energy consumption during convective drying of fruits and berries." E3S Web of Conferences 273 (2021): 07027. http://dx.doi.org/10.1051/e3sconf/202127307027.

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The work is dedicated to the calculation of energy costs for the realization of the process of convective drying of fruits and berries in a suspended layer. The energy consumption for the fan drive for organizing the air flow, providing the phenomenon of fluidization of fruits and berries, as well as the costs for supplying heat to the dehydration object have been calculated. The energy consumption was determined for various options of energy supply: using a heat pump and due to the operation of thermoelectric heaters (TEH). It is found that the largest proportion of the energy consumption for air circulation organization. It has been established that from the energy point of view, of all the investigated freons, the refrigerant R410 is the most efficient, the total energy consumption for dehydration of 1 kg of irgi berries with it is 7102 kJ, for honeysuckle - 9765 kJ / kg, for lingonberry - 7989 kJ / kg. Comparative analysis revealed that the use of a heat pump installation of convective drying fruits and berries in the fluidized bed reduces the power consumption by an average of 13% in comparison with drying by using heaters to heat the coolant.
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41

Tangwe, S., and K. Kusakana. "Evaluation of the coefficient of performance of an air source heat pump unit and an air to water heat pump." Journal of Energy in Southern Africa 32, no. 1 (February 18, 2021): 27–40. http://dx.doi.org/10.17159/2413-3051/2021/v32i1a7935.

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Air source heat pump (ASHP) water heaters are efficient devices for sanitary hot water heating. The coefficient of performance (COP) of the air to water heat pump (AWHP) is constantly lower than that of the corresponding ASHP unit. The study focused on determining the COP of both the ASHP unit and the AWHP. This was achieved by the implementation of both experimental and simulation methods, with the help of a data acquisition system and the REFPROP software. The system comprised of a 1.2 kW split type ASHP unit and a 150 L high pressure geyser. A power meter, flow meters, temperature sensors, pressure sensors, ambient temperature and relative humidity sensor were installed at precise locations on the split type AWHP. Controlled volumes of 150, 50 and 100 L were drawn off from the AWHP during the morning, afternoon and evening for a year. The average COP for the summer and winter, in terms of the input electrical and output thermal energies of the AWHP were 3.02 and 2.30. The COPs of the ASHP unit, in terms of the change in the enthalpies of the refrigerant at the inlet and the outlet of the condenser and the evaporator, were 3.52 and 2.65 respectively. The study showed that the difference between the COP of the ASHP unit and that of the AWHP could be ascribed to the electrical energy consumed by the fan and the water circulation pump during the vapour compression refrigeration cycles. The work provides an energy optimisation opportunity to the manufacturers of this technology, helping to enhance the efficiency and COP of ASHP water heaters. Highlights The COPt of the ASHP unit was higher than the COPe of the AWHP. The COPe of the AWHP was the ratio of the input electrical energy consumed and the output thermal energy gained by the stored water. The COPt of the ASHP unit was enthalpies-dependent and a function of inlet and outlet enthalpies of the evaporator and condenser. The inlet and outlet refrigerant temperatures profiles of the condenser confirmed thermal energy dissipation.
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42

Abdi Pranata, I. Gede, Kadek Rihendra Dantes, and I. Nyoman Pasek Nugraha. "STUDI KOMPARASI PERBANDINGAN AIR DAN UDARA SEBAGAI MEDIA PENDINGIN KONDENSOR TERHADAP PENCAPAIAN SUHU OPTIMAL SIKLUS PRIMER PADA PROTOTIPE WATER CHILLER." Jurnal Pendidikan Teknik Mesin Undiksha 7, no. 1 (September 4, 2019): 18. http://dx.doi.org/10.23887/jjtm.v7i1.18754.

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Kondensor adalah sebuah alat pada sistem refrigerasi mesin pendingin yang berfungsi sebagai pemindah panas pada refrigerant yang memiliki temperatur tinggi akan diserap lalu dihembuskan oleh media penghambat panas yang ada pada kondensor sehingga menyebakan uap refrigerant mengembun menjadi cair. Air merupakan media pendinginan yang tepat sebagai media pendinginan untuk kondensor, karena air memiliki konduktifitas termal lebih baik dibandingkan dengan udara yaitu dengan nilai air 0,56 J/m.s.̊C dan udara 0,023 J/m.s.̊C . Sehingga laju perpindahan panas lebih cepat dan suhu yang dihasilkan dengan rentang waktu 20 menit kerja pada chilled water tank supply. Penelitian dilakukan secara eksperimen dengan posisi kondensor didalam air yang dialiri air bersikulasi melalui saluran dari wadah kondensor, lalu mengalir ke wadah 1 dan 2 yang sudah disediakan, kemudian disirkulasikan kembali menuju wadah kondensor. Hasil yang didapat dari penelitian menunjukan suhu yang dihasilkan oleh air pendingin kondensor dengan nilai 6,725 ̊C lebih baik dibandingkan dengan udara pendingin kondensor dengan nilai 14,25 ̊C dalam waktu 20 menitKata Kunci : Kondensor, air, suhu, air pendingin kondensor, udara pendingin kondensor The condenser is a device in the refrigeration system that functions as a heat transfer machine in refrigerants that have high temperatures will be absorbed and then exhaled by heat inhibiting media that are on the condenser so that the refrigerant vapor condenses into liquid. Water is the right cooling medium as a cooling medium for condensers, because water has better thermal conductivity than air, with a water value of 0.56 J / m.Co and air 0.023 J / m.Co. So that the heat transfer rate is faster and the temperature produced with a span of 20 minutes works on the chilled water tank supply. The study was carried out experimentally with the condenser position in water circulating through water from the condenser container, then flowing into containers 1 and 2 that have been provided, then recirculated to the condenser container. The results obtained from the study showed that the temperature produced by the water cooled condenser with a value of 6.725 ̊C was better than the air cooled condenser with a value of 14.25 ̊C within 20 minuteskeyword : Condenser, water, temperature, water cooled condenser, air cooled condenser
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43

Nielson, Dennis L., Chris Delahunty, John W. Goodge, and Jeffery P. Severinghaus. "Facility for testing ice drills." Scientific Drilling 22 (May 31, 2017): 29–33. http://dx.doi.org/10.5194/sd-22-29-2017.

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Abstract. The Rapid Access Ice Drill (RAID) is designed for subsurface scientific investigations in Antarctica. Its objectives are to drill rapidly through ice, to core samples of the transition zone and bedrock, and to leave behind a borehole observatory. These objectives required the engineering and fabrication of an entirely new drilling system that included a modified mining-style coring rig, a unique fluid circulation system, a rod skid, a power unit, and a workshop with areas for the storage of supplies and consumables. An important milestone in fabrication of the RAID was the construction of a North American Test (NAT) facility where we were able to test drilling and fluid processing functions in an environment that is as close as possible to that expected in Antarctica. Our criteria for site selection was that the area should be cold during the winter months, be located in an area of low heat flow, and be at relatively high elevation. We selected a site for the facility near Bear Lake, Utah, USA. The general design of the NAT well (NAT-1) started with a 27.3 cm (10.75 in.) outer casing cemented in a 152 m deep hole. Within that casing, we hung a 14 cm (5.5 in.) casing string, and, within that casing, a column of ice was formed. The annulus between the 14 and 27.3 cm casings provided the path for circulation of a refrigerant. After in-depth study, we chose to use liquid CO2 to cool the hole. In order to minimize the likelihood of the casing splitting due to the volume increase associated with freezing water, the hole was first cooled and then ice was formed in increments from the bottom upward. First, ice cubes were placed in the inner liner and then water was added. Using this method, a column of ice was incrementally prepared for drilling tests. The drilling tests successfully demonstrated the functioning of the RAID system. Reproducing such a facility for testing of other ice drilling systems could be advantageous to other research programs in the future.
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Kunert, Anna T., Mark Lamneck, Frank Helleis, Ulrich Pöschl, Mira L. Pöhlker, and Janine Fröhlich-Nowoisky. "Twin-plate Ice Nucleation Assay (TINA) with infrared detection for high-throughput droplet freezing experiments with biological ice nuclei in laboratory and field samples." Atmospheric Measurement Techniques 11, no. 11 (November 23, 2018): 6327–37. http://dx.doi.org/10.5194/amt-11-6327-2018.

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Abstract. For efficient analysis and characterization of biological ice nuclei under immersion freezing conditions, we developed the Twin-plate Ice Nucleation Assay (TINA) for high-throughput droplet freezing experiments, in which the temperature profile and freezing of each droplet is tracked by an infrared detector. In the fully automated setup, a couple of independently cooled aluminum blocks carrying two 96-well plates and two 384-well plates, respectively, are available to study ice nucleation and freezing events simultaneously in hundreds of microliter-range droplets (0.1–40 µL). A cooling system with two refrigerant circulation loops is used for high-precision temperature control (uncertainty <0.2 K), enabling measurements over a wide range of temperatures (∼ 272–233 K) at variable cooling rates (up to 10 K min−1). The TINA instrument was tested and characterized in experiments with bacterial and fungal ice nuclei (IN) from Pseudomonas syringae (Snomax®) and Mortierella alpina, exhibiting freezing curves in good agreement with literature data. Moreover, TINA was applied to investigate the influence of chemical processing on the activity of biological IN, in particular the effects of oxidation and nitration reactions. Upon exposure of Snomax® to O3 and NO2, the cumulative number of IN active at 270–266 K decreased by more than 1 order of magnitude. Furthermore, TINA was used to study aqueous extracts of atmospheric aerosols, simultaneously investigating a multitude of samples that were pre-treated in different ways to distinguish different kinds of IN. For example, heat treatment and filtration indicated that most biological IN were larger than 5 µm. The results confirm that TINA is suitable for high-throughput experiments and efficient analysis of biological IN in laboratory and field samples.
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45

Mukhtar, Hamza K., and Saud Ghani. "Hybrid Ejector-Absorption Refrigeration Systems: A Review." Energies 14, no. 20 (October 13, 2021): 6576. http://dx.doi.org/10.3390/en14206576.

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Absorption Refrigeration Systems (ARS) are potential alternatives to direct expansion (DX) refrigeration systems. This review focused on the incorporation of an ejector into absorption refrigeration cycles to constitute Hybrid Ejector-Absorption Refrigeration Systems (HEARS). The ejector adds several advantages to the absorption refrigeration systems depending on its location in the cycle. The two prevalent configurations of HEARS are Triple pressure level (TPL-HEARS), and Low Pressure Condenser (LPC-HEARS). Previous studies revealed the preference of the latter configuration as it allows lower circulation ratios, enhances the refrigeration effect, and could achieve a COP up to 1. Moreover, LPC configuration is suitable with single, double, and variable-effect absorption systems with a COP of above unity. In turn, the TPL-HEARS notably enhances the absorption process, particularly when a variable geometry ejector is utilized. This configuration could obtain a COP around 1.1, but only with high-density refrigerant vapor. Lately, to attain the advantages of both configurations, some studies investigated the viability of adding two ejectors to the cycle. This paper meticulously reviews investigations conducted on the emerging dual ejectors-absorption refrigeration technology. This paper reveals the general performance trend and the maximum attainable COP by each type of hybrid ejector-absorption refrigeration system. DEARS and Ejector-driven absorption refrigeration systems (ED-ARS) could achieve COP that ranges between 1.2 and 1.46. The use of a flash tank and a RHE is essential in NH3/H2O HEARS. At high generator temperatures (of 120–170 °C), DEARS was found to be the system with less complexity and best performance. Nevertheless, the performance of the DEARS might drop significantly if the heat source temperature is fluctuating. Thence, the variable-effect HEARS is considered the best alternative. The capability of HEARS to be integrated with different power generation cycles is also highlighted. Finally, the review presents possible future research opportunities to improve the absorption refrigeration technology.
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46

Mukhtar, Hamza K., and Saud Ghani. "Hybrid Ejector-Absorption Refrigeration Systems: A Review." Energies 14, no. 20 (October 13, 2021): 6576. http://dx.doi.org/10.3390/en14206576.

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Absorption Refrigeration Systems (ARS) are potential alternatives to direct expansion (DX) refrigeration systems. This review focused on the incorporation of an ejector into absorption refrigeration cycles to constitute Hybrid Ejector-Absorption Refrigeration Systems (HEARS). The ejector adds several advantages to the absorption refrigeration systems depending on its location in the cycle. The two prevalent configurations of HEARS are Triple pressure level (TPL-HEARS), and Low Pressure Condenser (LPC-HEARS). Previous studies revealed the preference of the latter configuration as it allows lower circulation ratios, enhances the refrigeration effect, and could achieve a COP up to 1. Moreover, LPC configuration is suitable with single, double, and variable-effect absorption systems with a COP of above unity. In turn, the TPL-HEARS notably enhances the absorption process, particularly when a variable geometry ejector is utilized. This configuration could obtain a COP around 1.1, but only with high-density refrigerant vapor. Lately, to attain the advantages of both configurations, some studies investigated the viability of adding two ejectors to the cycle. This paper meticulously reviews investigations conducted on the emerging dual ejectors-absorption refrigeration technology. This paper reveals the general performance trend and the maximum attainable COP by each type of hybrid ejector-absorption refrigeration system. DEARS and Ejector-driven absorption refrigeration systems (ED-ARS) could achieve COP that ranges between 1.2 and 1.46. The use of a flash tank and a RHE is essential in NH3/H2O HEARS. At high generator temperatures (of 120–170 °C), DEARS was found to be the system with less complexity and best performance. Nevertheless, the performance of the DEARS might drop significantly if the heat source temperature is fluctuating. Thence, the variable-effect HEARS is considered the best alternative. The capability of HEARS to be integrated with different power generation cycles is also highlighted. Finally, the review presents possible future research opportunities to improve the absorption refrigeration technology.
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47

Luo, Win Jet, Kun Ying Li, Jeng Min Huang, and Chong Kai Yu. "Water Heating and Operational Mode Switching Effects on the Performance of a Multifunctional Heat Pump." Energies 13, no. 18 (September 18, 2020): 4896. http://dx.doi.org/10.3390/en13184896.

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In this study, a multifunctional air and water source heat pump system was developed with a parallel refrigerant piping arrangement, which possessed six operational functions: space cooling (SC), space heating (SH), water heating (WH), water cooling (WC) and two composite operational modes. The two composite operational modes were the SC/WH mode and the SH/WH mode. The performance of the multifuctional heat pump system under different ambient conditions was investigated based on the testing standards of CNS 14464 and CNS 15466. In this study, the effect of the direct water heating (DWH) and circulating water heating (CWH) methods on the performance was investigated. It was found that the water heating performance of the system by the DWH method is better than that of the system by the CWH method. The water heating capacity and COPw,h of the DWH method can be improvement by 2.6% to 22.1% and 2.9% to 50.8%, respectively. Moreover, this study developed a refrigerant pressure balance method to achieve an effective steady state of the refrigerant pressure after operational mode switching. By the refrigerant pressure balance method, the required time to attain the steady state could be greatly reduced—by 50%. However, the deviation of the refrigerant mass flow rate between the refrigerant pressure balance method and the refrigerant pump down method after operational mode switching ranged from 0.15% to 7.6%.
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48

Yamankaradeniz, Nurettin, Furkan Sokmen, Salih Coskun, Omer Kaynakli, and Bilsay Pastakkaya. "Performance analysis of a re-circulating heat pump dryer." Thermal Science 20, no. 1 (2016): 267–77. http://dx.doi.org/10.2298/tsci130426069y.

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A re-circulating heat pump dryer (HPD) system was designed, constructed and tested at steady state and transient conditions. Refrigerant 134a was used as a refrigerant in this system. The tests were performed to observe behavior of HPD system. So, changes of temperature and relative humidity of drying air through the dryer and heat pump operating temperatures were observed during the drying process and effects of bypass air ratio (BAR) on the system?s parameters as system performance and specific moisture extracted ratio (SMER) at steady state were investigated. The HPD system was also tested to investigate temperatures and relative humidity changes of drying air during drying process on the system?s parameters depend on time. Air flow rate circulated through the HPD system was 554m3/h during the all tests. According to test results, the system?s parameters did not change up to 40% of BAR. Then the COP and SMER values were decreased after 40% of BAR. While SMER values changed between 1.2 and 1.4, COPsys changed between 2.8 and 3.3 depend on BAR. As well as during the drying process, the COP and SMER values were also affected and decreased depend on time.
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49

Haque, Md Emdadul. "Ethylene Glycol Regeneration Plan: A Systematic Approach to Troubleshoot the Common Problems." Journal of Chemical Engineering 27 (July 27, 2013): 21–26. http://dx.doi.org/10.3329/jce.v27i1.15853.

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Mono Ethylene Glycol (MEG) is used primarily at low-temperature processing plant for extracting natural gas liquids. Typically a physical process plant comprises with gas dehydration system which allows for physical separation of water saturated gas by simple dew point depression and water condensation brought about by chilling from cross exchange with propane refrigerant. The resultant wet gas is prevented from freezing by injection of liquid desiccants to inhibit hydrate formation. The resulting dehydrated gas stream will have a dew point preciously equal to the saturated water volume of the gas at its coolest temperature. Mono Ethylene Glycol has been chosen as hydrate inhibitor because of its low volatility, low toxicity, low flammability, good thermodynamic behavior, and simple proven technology requirement and availability. But it has two common characteristic problems in regeneration plant that is fouling of equipment by iron carbonate, Ca+2/Mg+2 salt deposits and cross contamination of MEG and condensate contamination. MEG in condensate causes condensate specification problems, fouling of condensate stabilization equipment and contamination of wastewater streams. Condensate in MEG causes stripping effect due to condensate vaporization, lower operating temperature, higher MEG purities, and contamination of wastewater streams from MEG Regeneration system and burping of column due to condensate buildup. Another common problem is glycol losses due to carryover with dehydrated gas and which finally accumulates in pipelines and causes corrosion. Other reasons of glycol losses are higher column temperature, foaming, leaks at pump or pipe fittings, operated with excessive gas flow rates and rapid changes in gas flow rates. Column Flooding occurred if feed glycol circulation rate exceeded design limit and it does not allow proper separation of glycol and water separator and much glycol losses through vent line. This paper presents an experimental study of glycol losses. Effort has been made to investigate the causes and the study suggests some mitigation plans. Current study suggests the efficiency of the dehydration process depends on a large extent on the cleanliness of the glycol and the regular monitoring of glycol parameters such as glycol concentration, hydrocarbon content, salt content, solids content, pH stabilization, iron content, foaming tendency etc. Losses due to vaporization from reboiler can be minimized by adjusting operating parameters. By developing monitoring procedure and periodic maintenance about 90% operating problems of Glycol Regeneration Plant can be reduced. DOI: http://dx.doi.org/10.3329/jce.v27i1.15853 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 1, June 2012: 21-26
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50

Smirnov, Sergey, Mikhail Sinkevich, Yuri Antipov, and Hassan Khalife. "A method for evaluating the heat rejection efficiency in a Lunar power plant consisting of a free-piston Stirling engine (FPSE)." E3S Web of Conferences 313 (2021): 07001. http://dx.doi.org/10.1051/e3sconf/202131307001.

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A method for evaluating the heat rejection efficiency in a Lunar power plant consisting of a free-piston Stirling engine FPSE is proposed. The waste heat from the FPSE is absorbed by the refrigerant circulating in a closed pumped loop and then rejected through a radiator into space. The magnitude of the heat flux rejected through the radiator is determined by the temperature difference between the radiator fins and surrounding environment, as well as the surface areas of the radiator and the emissivity coefficient. The method developed is used to qualitatively evaluate the refrigerant efficiency based on calculating the average temperature of the radiator fin which is established during the heat exchange process in the radiator. The method allowed us to determine the most efficient refrigerant in terms of maximum heat rejection at a given operating temperature range without the need of detailed calculations like in the previous works of the authors. Computational studies in a two-dimensional formulation of the radiator, using helium or liquid ammonia as a refrigerant, to determine the quantitative characteristics of the heat rejection process and overall dimensions of the radiator were performed, and a comparative analysis of the results is presented.
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