International Journal of Air-conditioning and Refrigeration最新文献_第10页

Assessment of a Simpler Friction Factor in an Algebraic Solution for Adiabatic Coiled Capillary Tubes 绝热毛细管的一个更简单的摩擦系数的代数解的评估

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-11-25 DOI: 10.1142/s2010132520500339

Thiago Torres Martins Rocha, S. I. D. M. Resende, Hélio Augusto Goulart Diniz, F. A. R. Filho, Raphael Nunes de Oliveira

{"title":"Assessment of a Simpler Friction Factor in an Algebraic Solution for Adiabatic Coiled Capillary Tubes","authors":"Thiago Torres Martins Rocha, S. I. D. M. Resende, Hélio Augusto Goulart Diniz, F. A. R. Filho, Raphael Nunes de Oliveira","doi":"10.1142/s2010132520500339","DOIUrl":"https://doi.org/10.1142/s2010132520500339","url":null,"abstract":"In this work, the performance of an existing algebraic solution for adiabatic coiled capillary tubes, in subcritical cycles, is investigated. However, the C-M&N friction factor, commonly used, was replaced by Schmidt friction factor, which is less complex. Two existing dimensionless correlations were also evaluated for comparison. To assess the effect of altering the friction factor, experimental data collected in the literature were used as reference. Analyzing the present results and that with C-M&N friction factor, it was observed that adopting the Schmidt friction factor does not cause a relevant impact on the solution. The deviations of the predicted versus experimental mass flow rates were comprised in a range between –8% and 12%, with average deviation (AD), absolute average deviation (AAD) and root mean square (RMS) error of –0.1%, 2.7% and 3.4%, respectively. The empirical correlations presented unsatisfactory results, with maximum deviation around 40%. Therefore, it was concluded that using the Schmidt friction factor is adequate to reduce the complexity of the algebraic solution and to maintain the accuracy.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":"12 1","pages":"2050033"},"PeriodicalIF":1.0,"publicationDate":"2020-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87685807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Effects of Hydrophobicity and Drainage Velocity on Water Retention Behaviour in Porous Media: A Computational Study 疏水性和排水速度对多孔介质保水行为影响的计算研究

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-11-23 DOI: 10.1142/s2010132520500340

K. W. Yong, P. Ganesan, E. Hamidi, S. Kazi, S. Ramesh

引用次数: 0

Optimized Refrigerant Flow Rate and Dimensions of the Ejector Employed in a Modified Ejector Vapor Compression System 改进的喷射器蒸汽压缩系统中喷射器的优化制冷剂流量和尺寸

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-11-20 DOI: 10.1142/s2010132520500388

Dishant Sharma, G. Sachdeva, D. K. Saini

引用次数: 2

Rotary Compressor Performance at Low Ambient Temperatures 旋转压缩机在低温环境下的性能

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-11-18 DOI: 10.1142/s2010132520500376

S. Lowrey, G. Reboux

{"title":"Rotary Compressor Performance at Low Ambient Temperatures","authors":"S. Lowrey, G. Reboux","doi":"10.1142/s2010132520500376","DOIUrl":"https://doi.org/10.1142/s2010132520500376","url":null,"abstract":"Small rotary compressors are used in domestic heat pump appliances, for example, in domestic dehumidifiers and heat pump clothes dryers. Compressor performance curves provided by the manufacturer can be based on testing at relatively high ambient temperatures, in some cases as high as 35∘C. This can be much higher compared with the ambient temperature in which the compressor operates when, for example, it is installed in a domestic dehumidifier which can operate in ambient temperatures as low as 10∘C. We have developed a compressor calorimeter to test a small R134a rotary compressor extracted from a commercial domestic dehumidifier and use this to measure compressor performance parameters including the isentropic and volumetric efficiencies and the compressor heat loss fraction. The performance testing has been carried out at ambient temperatures 10∘C, 15∘C, 20∘C and 25∘C for a fixed relative humidity of 70% to compare how the compressor performance varies with the ambient temperature, and to determine how well the compressor performs outside of the performance envelope provided by the manufacturer. The results show that isentropic and volumetric efficiency of these small compressors is relatively insensitive to variation in ambient temperature, even outside of the performance envelope provided by the manufacturer. However, the compressor heat loss fraction can, on average, double from 15% to 30%, between operation at ambient 25∘C and ambient 10∘C. The data obtained in this work is used to construct compressor sub-models for certain ambient temperatures. We show how these sub-models can be used to improve a domestic dehumidifier model for operation at low ambient conditions within the evaporator frosting regime and good agreement is obtained between experimental and simulated data. The authors are not aware of a domestic dehumidifier model designed to work at ambient temperatures within the frosting regime.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81924580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Multi-Objective Optimization of Cascade Refrigeration System Using the Concept of Modified and Advanced Exergy, Risk Level and Thermal Inventory 基于改进和先进火用、风险水平和热库存概念的梯级制冷系统多目标优化

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-11-11 DOI: 10.1142/s2010132520500364

V. Jain, Rajiv Rawat, G. Sachdeva, V. Kumar

{"title":"Multi-Objective Optimization of Cascade Refrigeration System Using the Concept of Modified and Advanced Exergy, Risk Level and Thermal Inventory","authors":"V. Jain, Rajiv Rawat, G. Sachdeva, V. Kumar","doi":"10.1142/s2010132520500364","DOIUrl":"https://doi.org/10.1142/s2010132520500364","url":null,"abstract":"This work conceives the performance of vapor compression cascaded refrigeration system (CRS) from the exergy, safety and thermal inventory points of view employing the theory of effective temperature ([Formula: see text] than environment temperature ([Formula: see text] in Gouy–Stodola equation. Comparative results show that the actual irreversible loss in CRS is 8.1% higher. Further, advanced exergy analysis results showed that 17.985[Formula: see text]kW irreversible loss (out of 33.737[Formula: see text]kW irreversible loss) in the system is evadable with improvement in the system design. Besides, the vulnerability of toxic fluid R717 is reported in terms of the total risk level. Moreover, the economy matter is expressed in terms of its total thermal inventory. At the base case, total risk level and total thermal inventory are determined to be 454.3 US$ and 48.86[Formula: see text]kW/K, respectively. First, sensitivity analysis is carried out to evaluate the variation in irreversible loss, total risk level and thermal inventory at different evaporator and condenser temperatures with different degrees of overlap (decision variables). A total of nine simulations are designed using the Taguchi technique. Later, multi-objective optimization is employed. The optimization process reduced the total irreversibility and annual risk level of CRS by 10.2% and 8.9%, respectively, with 6.8% increase in thermal inventory.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":"36 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84373514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Experimental Evaluation of Window-Type Air-Conditioning Unit with New Expansion Device and R404A Alternative Refrigerant 新型膨胀装置和R404A替代制冷剂的开窗空调机组试验评价

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-10-27 DOI: 10.1142/s2010132520500315

A. Al-Sayyab

引用次数: 2

Analysis of Additive Alignment in a 90∘ Elbow Channel 90°肘形通道的加性对齐分析

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-10-21 DOI: 10.1142/S2010132520500327

H. Nguyen, D. Oh

引用次数: 1

Potential Alternative Materials used in Evaporative Coolers for Sustainable Energy Applications: A Review 可持续能源蒸发冷却器中潜在替代材料的研究进展

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-10-21 DOI: 10.1142/S2010132520300062

Shiva Kumar, J. Singh, Jogendra Siyag, S. Rambhatla

引用次数: 6

Effects of Nanostructure Additives on Supercooling and Freezing of Distilled Water 纳米结构添加剂对蒸馏水过冷和过冻的影响

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-10-21 DOI: 10.1142/s2010132520500297

Donggyu Lee, Donghyun Kim, Chaedong Kang

{"title":"Effects of Nanostructure Additives on Supercooling and Freezing of Distilled Water","authors":"Donggyu Lee, Donghyun Kim, Chaedong Kang","doi":"10.1142/s2010132520500297","DOIUrl":"https://doi.org/10.1142/s2010132520500297","url":null,"abstract":"The phenomenon of supercooling, which prevents freezing of water below the freezing point, is an obstacle to the production of inexpensive ice. In the case of ice heat storage systems using bio-preservation, low-temperature refrigeration of food and ice capsules in the HVAC industry, the supercooled water in capsules that indirectly come into contact with the outside is one of the problems that must be solved to maintain energy costs and the quality of food or organs. To improve this, experimental evaluation of additives that serve as crude nuclear agents is needed. However, research on this area needs to be supported because the types of additives are limited and their physical properties are unstable. In this paper, the effect of distilled water containing an additive of average diameter nanometer size on solution (frozen) supercooled below the freezing point was investigated. The supercooling time and supercooling level of each specimen were analyzed after addition of kaolin, strontium hydroxide, oxidizing mineral and nano-sized single-wall carbon nanotubes (SWCNT) as mineral fine particles in the distilled water. As a result, it has been confirmed that kaolin and SWCNT can be used as nuclear materials to release supercooling of water. In addition, when kaolin, a mineral fine particle, is used as a nuclear material, its size affects the performance of nuclearization. This confirmed the impact of nuclear material particle size and structure on overcooled emissions.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":"6 6 1","pages":"2050029"},"PeriodicalIF":1.0,"publicationDate":"2020-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84009860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Energy, Exergy, and Exergoeconomic Analysis of Solar Thermal Power Plant Hybrid with Designed PCM Storage 设计PCM储能的太阳能热电厂的能量、火用和耗力经济分析

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International Journal of Air-conditioning and Refrigeration Pub Date : 2020-10-19 DOI: 10.1142/s2010132520500303

M. Fani, N. Norouzi, Molood Ramezani

{"title":"Energy, Exergy, and Exergoeconomic Analysis of Solar Thermal Power Plant Hybrid with Designed PCM Storage","authors":"M. Fani, N. Norouzi, Molood Ramezani","doi":"10.1142/s2010132520500303","DOIUrl":"https://doi.org/10.1142/s2010132520500303","url":null,"abstract":"The tendency of renewable energies is one of the consequences of changing attitudes towards global energy issues. As a result, solar energy, which is the leader among renewable energies based on availability and potential, plays a crucial role in thoroughly filing global needs. Significant problems with the solar thermal power plants (STPP) are the operation time, which is limited by daylight and is approximately half of the power plants with fossil fuels, and the capital cost. In the present study, a new suggested sketch of adding latent heat storage (LHS) filled with commercial phase change material (PCM) to a 500-kW STPP case study has been investigated. Solar system details and irradiation amounts for a case study, including total and beam radiation have been determined. Also, the theoretical energetic and exergetic analysis of adding PCM storage to STTP is conducted, which showed a 19% improvement in the exergetic efficiency of the power plant to reach 30%. Besides, an optimized storage tank and appropriate PCM material have been investigated and selected concerning the practical limitations of the case study. By designing a new cycle, the LHS will be charged during daylight and will be discharged at night, doubling power plant operation time up to 2500[Formula: see text]h. Finally, exergoeconomic survey of STPP hybrid with PCM storage was carried out using Engineering Equation Solver (EES) program with genetic algorithm (GA) for three different scenarios, based on eight decision variables, which led us to decrease final product cost (electricity) in optimized scenario up to 30% compared to base case scenario from 28.99 to 20.27 $/kWh for the case study. Also, a comparison is made to demonstrate the effectiveness of the proposed new cycle on 250, 500, 1000, and 2000 kW STTPs.","PeriodicalId":13757,"journal":{"name":"International Journal of Air-conditioning and Refrigeration","volume":"28 1","pages":"2050030"},"PeriodicalIF":1.0,"publicationDate":"2020-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82848520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10