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New refrigeration system using CO vapor-solid as refrigerant

HUANG Dongping, DING Guoliang, QUACK Hans

《能源前沿(英文)》 2008年 第2卷 第4期   页码 494-498 doi: 10.1007/s11708-008-0070-x

摘要: A refrigerant must be in the vapor-liquid phase in a vapor-compression refrigeration system, therefore, CO cannot be used as a refrigerant for temperatures lower than -56°C because solid CO will form under the triple point temperature of -56°C. A refrigeration system with CO vapor-solid particles as refrigerant is put forward, by which a temperature lower than the triple point is achieved. An adjustable nozzle, a sublimator, a high-pressure regulating valve and a low-pressure regulating valve are used to replace the conventional evaporator. Theoretical cycle analysis of the refrigeration system shows that its COP can be 50% higher than that of the conventional one.

关键词: refrigerant     adjustable     temperature     vapor-compression refrigeration     sublimator    

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

《能源前沿(英文)》 2019年 第13卷 第1期   页码 185-192 doi: 10.1007/s11708-017-0452-z

摘要: Solar absorption-subcooled compression hybrid refrigeration system is a new type of efficient and economical solar refrigeration device which always meets the demand of cooling load with the change of solar irradiance. The performance of the hybrid system is higher due to the improvement of evaporator temperature of absorption subsystem. But simultaneously, the variation of working process as well as performance is complicated since the absorption and compression subsystems are coupled strongly. Based on the measured meteorological data of Guangzhou, a subtropical city in south China, a corresponding parametric model has been developed for the hybrid refrigeration system, and a program written by Fortran has been used to analyze the performance of the hybrid system under different external conditions. As the condensation temperature ranges from 38°C to 50°C, the working time fraction of the absorption subsystem increases from 75% to 85%. Besides, the energy saving fraction also increases from 5.31% to 6.02%. The average COP of the absorption subsystem is improved from 0.366 to 0.407. However, when the temperature of the absorption increases from 36°C to 48°C, the average COP of hybrid system decreases from 2.703 to 2.312. Moreover, the working time fraction of the absorption subsystem decreases from 80% to 71.7%. The energy saving fraction falls from 5.67% to 5.08%. In addition, when the evaporate temperature increases from 4°C to 14°C, the average COP of the absorption subsystem decreases from 0.384 to 0.365. The work of the compressor decreases from 48.2 kW to 32.8 kW and the corresponding average COP of the absorption subsystem is improved from 2.591 to 3.082.

关键词: solar     absorption-subcooled     compression hybrid     dynamic simulation     performance analysis    

Polymeric nanocomposites for electrocaloric refrigeration

《能源前沿(英文)》 2023年 第17卷 第4期   页码 450-462 doi: 10.1007/s11708-022-0858-0

摘要: Electrocaloric refrigeration represents an alternative solid-state cooling technology that has the potential to reach the ultimate goal of achieving zero-global-warming potential, highly efficient refrigeration, and heat pumps. To date, both polymeric and inorganic oxides have demonstrated giant electrocaloric effect as well as respective cooling devices. Although both polymeric and inorganic oxides have been identified as promising cooling methods that are distinguishable from the traditional ones, they still pose many challenges to more practical applications. From an electrocaloric material point of view, electrocaloric nanocomposites may provide a solution to combine the beneficial effects of both organic and inorganic electrocaloric materials. This article reviews the recent advancements in polymer-based electrocaloric composites and the state-of-the-art cooling devices operating these nanocomposites. From a device point of view, it discusses the existing challenges and potential opportunities of electrocaloric nanocomposites.

关键词: nanocomposites     electrocaloric     refrigeration     polymer    

Heat transfer characteristics of high heat flux vapor chamber

Dongchuan MO, Shushen LU, Haoliang ZHENG, Chite CHIN,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 166-170 doi: 10.1007/s11708-009-0076-z

摘要: To meet the challenge of heat spreading in electronic products, highly efficient high heat flux heat transfer vapor chambers have been manufactured and their heat transfer characteristics have been studied by a fast test system. A solid copper block with the same shape as the vapor chamber is used to compare the performance of the vapor chamber. The result shows that, it will take about 5min to achieve a steady state in the fast test system. The heat transfer characteristics of the vapor chamber are more superior to those of the copper block. In this paper, total thermal resistance of the test system is used to evaluate the heat transfer characteristics of the vapor chamber, because it has already been used to consider both the spreading thermal resistance and the flatness of the vapor chamber.

关键词: high heat flux     vapor chamber (VC)     heat transfer characteristics     fast test    

analysis of cogeneration systems based on micro gas turbine (MGT), organic Rankine cycle and ejector refrigeration

Zemin BO, Kai ZHANG, Peijie SUN, Xiaojing LV, Yiwu WENG

《能源前沿(英文)》 2019年 第13卷 第1期   页码 54-63 doi: 10.1007/s11708-018-0606-7

摘要: In this paper, the operation performance of three novel kinds of cogeneration systems under design and off-design condition was investigated. The systems are MGT (micro gas turbine) + ORC (organic Rankine cycle) for electricity demand, MGT+ ERC (ejector refrigeration cycle) for electricity and cooling demand, and MGT+ ORC+ ERC for electricity and cooling demand. The effect of 5 different working fluids on cogeneration systems was studied. The results show that under the design condition, when using R600 in the bottoming cycle, the MGT+ ORC system has the lowest total output of 117.1 kW with a thermal efficiency of 0.334, and the MGT+ ERC system has the largest total output of 142.6 kW with a thermal efficiency of 0.408. For the MGT+ ORC+ ERC system, the total output is between the other two systems, which is 129.3 kW with a thermal efficiency of 0.370. For the effect of different working fluids, R123 is the most suitable working fluid for MGT+ ORC with the maximum electricity output power and R600 is the most suitable working fluid for MGT+ ERC with the maximum cooling capacity, while both R600 and R123 can make MGT+ ORC+ ERC achieve a good comprehensive performance of refrigeration and electricity. The thermal efficiency of three cogeneration systems can be effectively improved under off-design condition because the bottoming cycle can compensate for the power decrease of MGT. The results obtained in this paper can provide a reference for the design and operation of the cogeneration system for distributed energy systems (DES).

关键词: cogeneration system     different working fluids     micro gas turbine (MGT)     organic Rankine cycle (ORC)     ejector refrigeration cycle (ERC)    

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1415-1425 doi: 10.1007/s11709-021-0786-9

摘要: To study the behavior of coral aggregate concrete (CAC) column under axial and eccentric compression, the compression behavior of CAC column with different types of steel and initial eccentricity (ei) were tested, and the deformation behavior and ultimate bearing capacity (Nu) were studied. The results showed that as the ei increases, the Nu of CAC column decreases nonlinearly. Besides, the steel corrosion in CAC column is severe, which reduces the steel section and steel strength, and decreases the Nu of CAC column. The durability of CAC structures can be improved by using new organic coated steel. Considering the influence of steel corrosion and interfacial bond deterioration, the calculation models of Nu under axial and eccentric compression were presented.

关键词: coral aggregate concrete column     axial compression     eccentric compression     steel corrosion     calculation model    

Available energy analysis of new tandem double-capillary tube refrigeration system for refrigerator-freezers

HE Maogang, ZHANG Ying, SONG Xinzhou, ZHANG Jiantao

《能源前沿(英文)》 2008年 第2卷 第1期   页码 36-42 doi: 10.1007/s11708-008-0013-6

摘要: A new tandem double-capillary tube refrigeration system for refrigerator-freezers is proposed. A capillary tube was added between the two evaporators in the fresh and frozen food storage chests to raise the evaporation temperature of the refrigerating chamber, and reduce the heat exchange temperature difference and the available energy loss. Peng-Robinson (P-R) equation of state was adopted to calculate the thermodynamic properties of the refrigerants, and the available energy analysis of the vapor compression refrigeration cycle was programmed to calculate the thermodynamic performances of the new and the conventional refrigeration cycle of the refrigerator-freezer. The calculation results show that the available energy efficiency of the conventional refrigeration cycle of the refrigerator-freezer is 21.20% and 20.57%, respectively when the refrigerant is R12 and R134a, while that of the double-capillary tube refrigeration cycle of the refrigerator-freezer is 23.97% and 23.44%, respectively. By comparison, the available energy efficiency of the new refrigeration system increases by 13.07% and 13.95%, respectively.

Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension

WANG Huailiang, SONG Yupu

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 323-328 doi: 10.1007/s11709-008-0043-5

摘要: In order to meet the requirement for nonlinear analysis and design of mass concrete structures, the deformation behavior and strength of three-graded concrete specimens 250 mm × 250 mm × 400 mm with a maximum aggregate size of 80 mm and the corresponding wet-screened concrete specimens 150 mm × 150 mm × 300 mm with a maximum aggregate size of 40 mm were studied experimentally. Specimens subjected to biaxial compression-tension (C-T) and triaxial compression-compression-tension (C-C-T) stress states. Test data indicate that both the deformation and strength of the mass concrete specimens are lower than those of the corresponding wet-screened concrete small specimens, but the initial tangent modulus of the stress-strain curve of the former is greater than that of the latter. Test results show that the wet-screened effect and size effect of the specimens under complex stress states are obvious such that these should be considered in the design of mass concrete structures. In addition, respective failure criteria for mass concrete in principal stress space and octahedron stress space are proposed.

关键词: requirement     wet-screened concrete     compression-tension     maximum aggregate     principal    

Modeling of coal swelling induced by water vapor adsorption

Zhejun PAN

《化学科学与工程前沿(英文)》 2012年 第6卷 第1期   页码 94-103 doi: 10.1007/s11705-011-1172-2

摘要: Gas adsorption-induced coal swelling is a well-know phenomenon. Coal swelling or shrinkage by adsorption or desorption of water vapor has not been well understood but has significant implications on gas drainage process for underground coal mining and for primary and enhanced coalbed methane production. Decreased matrix moisture content leads to coal shrinkage and thus the change of cleat porosity and permeability under reservoir conditions. Unlike gas adsorption in coal which usually forms a single layer of adsorbed molecules, water vapor adsorption in the coal micropores forms multilayer of adsorbed molecules. In this work, a model has been developed to describe the coal swelling strain with respect to the amount of moisture intake by the coal matrix. The model extended an energy balance approach for gas adsorption-induced coal swelling to water vapor adsorption-induced coal swelling, assuming that only the first layer of adsorbed molecules of the multilayer adsorption changes the surface energy, which thus causes coal to swell. The model is applied to describe the experimental swelling strain data measured on an Australian coal. The results show good agreement between the model and the experimental data.

关键词: multilayer adsorption     vapour pressure     coal shrinkage     relative humidity     permeability    

Research on performance of mixed absorption refrigeration for solar air-conditioning

WAN Zhongmin, SHU Shuiming, HU Xinhua, WANG Biaohua

《能源前沿(英文)》 2008年 第2卷 第2期   页码 222-226 doi: 10.1007/s11708-008-0017-2

摘要: A novel lithium bromide/water mixed absorption refrigeration cycle that is suitable for the utilization of solar air-conditioning and can overcome the drawbacks of low system overall efficiency of traditional solar absorption refrigeration air-condition systems is presented. The accessorial high pressure generator was added in the cycle. The lithium bromide solution flowing out from the high pressure generator was mixed with the solution from the low pressure absorber to increase lithium bromide solution concentration and decrease pressure in the high pressure absorber. The performance of a mixed absorption refrigeration cycle was analyzed. The theoretical analysis shows that the highest COP is 0.61, while the highest available temperature difference of heat resource is 33.2°C. The whole coefficient of performance of the solar air-conditioning using mixed absorption cycle is 94.5% higher than that of two-stage absorption. The advantages of solar air-conditioning can be markedly made use of by the cycle.

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

D. SENDIL KUMAR,R. ELANSEZHIAN

《机械工程前沿(英文)》 2014年 第9卷 第1期   页码 75-80 doi: 10.1007/s11465-014-0285-y

摘要:

In this paper the reliability and performance of a vapour compression refrigeration system with ZnO nanoparticles in the working fluid was investigated experimentally. Nanorefrigerant was synthesized on the basis of the concept of the nanofluids, which was prepared by mixing ZnO nanoparticles with R152a refrigerant. The conventional refrigerant R134a has a global warming potential (GWP) of 1300 whereas R152a has a significant reduced value of GWP of 140 only. An experimental test rig is designed and fabricated indigenously in the laboratory to carry out the investigations. ZnO nanoparticles with refrigerant mixture were used in HFC R152a refrigeration system. The system performance with nanoparticles was then investigated. The concentration of nano ZnO ranges in the order of 0.1% v, 0.3% v and 0.5%v with particle size of 50 nm and 150 g of R152a was charged and tests were conducted. The compressor suction pressure, discharge pressure and evaporator temperature were measured. The results indicated that ZnO nanorefrigerant works normally and safely in the system. The ZnO nanoparticle concentration is an important factor considered for heat transfer enhancement in the refrigeration system. The performance of the system was significantly improved with 21% less energy consumption when 0.5%v ZnO-R152a refrigerant. Both the suction pressure and discharge pressure were lowered by 10.5% when nanorefrigerant was used. The evaporator temperature was reduced by 6% with the use of nanorefrigerant. Hence ZnO nanoparticles could be used in refrigeration system to considerably reduce energy consumption. The usage of R152a with zero ozone depleting potential (ODP) and very less GWP and thus provides a green and clean environment. The complete experimental results and their analysis are reported in the main paper.

关键词: ZnO nanorefrigerant     reduced GWP     COP     pressure ratio green energy    

Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

《能源前沿(英文)》 2007年 第1卷 第4期   页码 463-467 doi: 10.1007/s11708-007-0068-0

摘要: The effects of homogeneous charge compression ignition (HCCI) engine compression ratio on its combustion characteristics were studied experimentally on a modified TY1100 single cylinder engine fueled with dimethyl ether. The resul

关键词: homogeneous     cylinder     combustion     compression     dimethyl    

Thermodynamic study on dynamic water and organic vapor sorption on amorphous valnemulin hydrochloride

Jinbo OUYANG, Jingkang WANG, Yongli WANG, Qiuxiang YIN, Hongxun HAO

《化学科学与工程前沿(英文)》 2015年 第9卷 第1期   页码 94-104 doi: 10.1007/s11705-015-1460-3

摘要: The sorption of water and organic vapors on valnemulin hydrochloride was determined by dynamic vapor sorption at 25 °C. The adsorption-desorption behavior of water vapor and a series of organic vapors was investigated to probe the structural changes in valnemulin hydrochloride before and after sorption. The isothermal adsorption equilibrium data was evaluated using Guggenheim-Anderson-deBoer (GAB) and Brunauer-Emmett-Teller (BET) models. The BET model is applicable only at low relative pressures (0.1≤RP≤0.4) while the GAB model is applicable in the whole range of RPs (0.1≤RP≤0.9). The sorption kinetics at high RPs was determined by fitting the sorption data to the Avrami equation and the sorption content time relationship could be predicted by the Avrami equation. Finally, the possible sorption mechanism of valnemulin hydrochloride was also discussed.

关键词: valnemulin hydrochloride     water vapor     organic vapors     sorption     kinetics    

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 432-439 doi: 10.1007/s11708-009-0050-9

摘要: A detailed chemical dynamical mechanism of oxidation of n-heptane was implemented into kiva-3 code to study the ignition mechanism of a high-temperature, high-pressure, three-dimensional-space, transient turbulent, non-homogeneous, mono-component fuel in the engine. By testing the quantity of the heat released by the chemical reaction within the cylinder cell, the elementary reaction showing an obvious increase in the cell temperature was defined as ignition reaction and the corresponding cell as ignition position. The main pathway of the ignition reaction was studied by using the reverse deducing method. The result shows that the ignition in the engine can be divided into low-temperature ignition and high-temperature ignition, both of which follow the same rule in releasing heat, called the impulse heat releasing feature. Low-temperature ignition reaction, whose ignition reaction is c5h9o1-4=ch3cho+c3h5-a, follows the oxidation mechanism, while high-temperature ignition reaction, whose ignition reaction is c2h3o1-2=ch3co, follows the decomposition mechanism. No matter which ignition it is in, the chemical reaction that restrains the ignition reaction from lasting is the deoxidization reaction of alkylperoxy radicals.

关键词: compression-ignition engine     ignition mechanism     elementary reaction     n-heptane    

of carbon nanotubes in a continuous inclined mobile-bed rotating reactor via the catalytic chemical vapor

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 280-289 doi: 10.1007/s11705-017-1635-1

摘要: This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes (CNTs) via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词: carbon nanotubes     catalytic chemical vapor deposition     inclined rotating reactor     industrial process     scaling-up    

标题 作者 时间 类型 操作

New refrigeration system using CO vapor-solid as refrigerant

HUANG Dongping, DING Guoliang, QUACK Hans

期刊论文

Performance analysis of solar absorption-subcooled compression hybrid refrigeration system in subtropical

Xiangyang YE,Liming LIU,Zeyu LI

期刊论文

Polymeric nanocomposites for electrocaloric refrigeration

期刊论文

Heat transfer characteristics of high heat flux vapor chamber

Dongchuan MO, Shushen LU, Haoliang ZHENG, Chite CHIN,

期刊论文

analysis of cogeneration systems based on micro gas turbine (MGT), organic Rankine cycle and ejector refrigeration

Zemin BO, Kai ZHANG, Peijie SUN, Xiaojing LV, Yiwu WENG

期刊论文

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete

期刊论文

Available energy analysis of new tandem double-capillary tube refrigeration system for refrigerator-freezers

HE Maogang, ZHANG Ying, SONG Xinzhou, ZHANG Jiantao

期刊论文

Behavior of dam concrete under biaxial compression-tension and triaxial compression-compression-tension

WANG Huailiang, SONG Yupu

期刊论文

Modeling of coal swelling induced by water vapor adsorption

Zhejun PAN

期刊论文

Research on performance of mixed absorption refrigeration for solar air-conditioning

WAN Zhongmin, SHU Shuiming, HU Xinhua, WANG Biaohua

期刊论文

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

D. SENDIL KUMAR,R. ELANSEZHIAN

期刊论文

Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

期刊论文

Thermodynamic study on dynamic water and organic vapor sorption on amorphous valnemulin hydrochloride

Jinbo OUYANG, Jingkang WANG, Yongli WANG, Qiuxiang YIN, Hongxun HAO

期刊论文

Numerical study of ignition mechanism of n-heptane direct injection compression-ignition engine

Xiaoping GUO, Zhanjie WANG,

期刊论文

of carbon nanotubes in a continuous inclined mobile-bed rotating reactor via the catalytic chemical vapor

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

期刊论文