International Journal of Refrigeration最新文献

Tribological and residential air conditioning performance using SiO2-TiO2/PVE nanolubricant 使用 SiO2-TiO2/PVE 纳米润滑剂的摩擦学性能和住宅空调性能

International Journal of Refrigeration Pub Date : 2024-01-06 DOI: 10.1016/j.ijrefrig.2024.01.002

W.H. Azmi, M.F. Ismail, N.N.M. Zawawi, R. Mamat, S. Safril

{"title":"Tribological and residential air conditioning performance using SiO2-TiO2/PVE nanolubricant","authors":"W.H. Azmi, M.F. Ismail, N.N.M. Zawawi, R. Mamat, S. Safril","doi":"10.1016/j.ijrefrig.2024.01.002","DOIUrl":"https://doi.org/10.1016/j.ijrefrig.2024.01.002","url":null,"abstract":"Applying nanoparticles as an additive may increase the lubrication performance of the oil. The present paper evaluates the tribological performance of SiO2-TiO2 nanoparticles in PVE lubricant and its effect on the system's performance in residential air conditioning (RAC). The hybrid nanolubricants with a concentration from 0.003 to 0.01% at a 50:50 ratio were tested using the four-ball tribological method and then applied in a customised RAC test rig. The friction coefficient and wear scar diameter were evaluated to synthesise nanolubricant anti-wear effect on a paired surface. The coefficient of performance (COP), cooling capacity, power consumption, and energy efficiency ratio (EER) were analysed to understand the influence of SiO2-TiO2/PVE nanolubricant in the RAC system. About 25% reduction in frictional coefficient was discovered when the nanoparticles were added into lubricant with a concentration of 0.005%. Applying nanolubricant in the RAC system can reduce compressor work and power consumption, increase the refrigerant flow rate and cooling capacity, and increase the COP and EER. Maximum enhancement of 39.2% and 52.7% for COP and EER were found for nanolubricant at concentrations of 0.005%. The 0.005% concentration is the nanoparticle's concentration threshold for SiO2-TiO2/PVE, as the higher concentration may lead to the performance of a pure lubricant.","PeriodicalId":14367,"journal":{"name":"International Journal of Refrigeration","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139376317","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: 0

A 2 kW-class free-piston Stirling heat pump prototype suitable for cold regions for domestic heating 适用于寒冷地区家庭供暖的 2 千瓦级自由活塞斯特林热泵样机

International Journal of Refrigeration Pub Date : 2023-12-22 DOI: 10.1016/j.ijrefrig.2023.12.030

Longran Dai, Kaiqi Luo, Yanlei Sun, Jianying Hu, Limin Zhang, Zhanghua Wu, Ercang Luo

{"title":"A 2 kW-class free-piston Stirling heat pump prototype suitable for cold regions for domestic heating","authors":"Longran Dai, Kaiqi Luo, Yanlei Sun, Jianying Hu, Limin Zhang, Zhanghua Wu, Ercang Luo","doi":"10.1016/j.ijrefrig.2023.12.030","DOIUrl":"https://doi.org/10.1016/j.ijrefrig.2023.12.030","url":null,"abstract":"Compared with conventional vapour-compression heat pump technology, the free-piston Stirling heat pump technology attracts wide attention for its high efficiency, reliability, and environmental friendliness. In this work, a free-piston Stirling heat pump prototype with a two-kilowatt capacity, which can operate with an outside ambient temperature ranging from -20 to 10 °C, was designed, built and tested. First, numerical simulations were carried out to explore the distributions of the acoustic field and exergy loss. Second, the effects of several operating parameters on the heating performance were numerically investigated in detail. Finally, to validate the accuracy of the simulation results, verification experiments were conducted on the experimental platform of a free-piston Stirling heat pump driven by a dual-opposed linear compressor. Experimental data show that with a hot-end temperature of 45 °C and outside ambient temperature of 0 °C, the prototype achieved a heating capacity of 2253 W with a corresponding COPh of 2.76 (based on PV power input) and a relative Carnot efficiency of 39.1%; in particular, the prototype was able to achieve a COPh of 2.5 when pumping heat from -20 °C to 45 °C for 3.25 MPa mean pressure. The simulation and experimental results demonstrated that the free-piston Stirling heat pump system has good potential to achieve high efficiency as a heating supply in a cold region.","PeriodicalId":14367,"journal":{"name":"International Journal of Refrigeration","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029517","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: 0

Experimental investigation on boiling heat transfer characteristics of R1234yf/R1336mzz(Z) in horizontal flow 水平流动中 R1234yf/R1336mzz(Z) 沸腾传热特性的实验研究

International Journal of Refrigeration Pub Date : 2023-12-22 DOI: 10.1016/j.ijrefrig.2023.12.016

Mengtao Liu, Li Guo, Wei Li, Weicong Xu, Li Zhao

{"title":"Experimental investigation on boiling heat transfer characteristics of R1234yf/R1336mzz(Z) in horizontal flow","authors":"Mengtao Liu, Li Guo, Wei Li, Weicong Xu, Li Zhao","doi":"10.1016/j.ijrefrig.2023.12.016","DOIUrl":"https://doi.org/10.1016/j.ijrefrig.2023.12.016","url":null,"abstract":"Due to the inclusion of 18 HFCs, including R134a and R245fa, in the Kigali Amendment as controlled working fluids, the search for excellent alternatives to R134a and R245fa is urgent. R1234yf and R1336mzz(Z) are potential alternative working fluids to R134a and R245fa, but most studies have focused on the comparison of thermodynamic performance and boiling heat transfer capability of these pure working fluids. There is limited research on the boiling heat transfer performance of their mixed working fluids. Therefore, this study focuses on the flow boiling heat transfer characteristics of the mixed working fluid R134a/R245fa under non-azeotropic conditions. Experimental methods were employed to investigate the boiling heat transfer performance of the alternative working fluids R1234yf/R1336mzz(Z) (including R245fa/R1234yf and R1234yf/R1336mzz(Z) mixed working fluids) and evaluate the feasibility of R1234yf and R1336mzz(Z) as substitutes for R134a and R245fa. The results indicate that among the three mixed refrigerants, R134a/R245fa exhibits the highest heat transfer coefficient, while R1234yf/R1336mzz(Z) shows the lowest heat transfer coefficient. However, the differences in heat transfer coefficients among these three are relatively small, and their overall trends under different operating conditions are similar. It is evident that R134a/R245fa, with its good thermodynamic performance and stability, still holds potential as a transitional working fluid. R1234yf/R1336mzz(Z), with similar physical and thermodynamic properties, is an excellent alternative to R134a/R245fa.","PeriodicalId":14367,"journal":{"name":"International Journal of Refrigeration","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029283","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: 0

Two-phase flow condensation heat transfer characteristics of R-134a inside three-dimensional cylindrical micropillar enhanced tube 三维圆柱形微柱增强管内 R-134a 的两相流冷凝传热特性

International Journal of Refrigeration Pub Date : 2023-12-22 DOI: 10.1016/j.ijrefrig.2023.12.029

Anil Kumar, Ravi Kumar, Arup Kumar Das

{"title":"Two-phase flow condensation heat transfer characteristics of R-134a inside three-dimensional cylindrical micropillar enhanced tube","authors":"Anil Kumar, Ravi Kumar, Arup Kumar Das","doi":"10.1016/j.ijrefrig.2023.12.029","DOIUrl":"https://doi.org/10.1016/j.ijrefrig.2023.12.029","url":null,"abstract":"This paper presents an experimental investigation for evaluation of heat transfer coefficient, frictional pressure drops and flow regimes with their transitions during the condensation of R-134a inside a smooth, two microfins (MF1 and MF2) and a newly developed micropillar (MP) tubes. The experiments are carried out for a range of mass flux at an average saturation temperature of 35°C. Micropillar tube has produced the maximum heat transfer coefficient, while the microfin (MF1) tube resulted the highest frictional pressure gradient compared to other tubes. The experimental observations of microfin and micropillar tubes are plotted on the mass flux versus vapor quality flow map and Taitel and Duckler flow map to discuss the transitions within different flow patterns achieved. Visual inspection of the flow regimes with varying mass flux and vapor quality showed stratified-wavy, intermittent, and annular flow regimes. The occurrence of annular flow is found to be more in MF1 and MP tube. A performance evaluation factor (PEF) is defined to evaluate the thermal-hydraulic performance of the tubes. Using the same, it has been observed that the newly developed MP tube has a PEF value greater than unity which suggest augmentation of heat transfer coefficient at the expense of lesser pressure drop penalty.","PeriodicalId":14367,"journal":{"name":"International Journal of Refrigeration","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029315","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: 0

Thermal design and optimization of high-temperature heat pump integrated with district heating benchmarked in Denmark for process heat supply: “Optimisation d'une pompe à chaleur haute température en cascade intégrée au chauffage urbain, référencée au Danemark pour l'approvisionnement en chaleur industrielle: conception thermique et sélection du fluide de travail” 高温热泵的热设计和优化与丹麦的区域供热相结合，用于工艺供热："Optimisation d'une pompe à chaleur haute température en cascade intégrée au chauffage urbain, référencée au Danemark pour l'approvisionnement en chaleur industrielle: conception thermique et sélection du fluide de travail"。

International Journal of Refrigeration Pub Date : 2023-12-21 DOI: 10.1016/j.ijrefrig.2023.12.025

Mohsen Sadeghi, Tage Petersen, Zhenyu Yang, Benjamin Zühlsdorf, Kim Stenholdt Madsen

{"title":"Thermal design and optimization of high-temperature heat pump integrated with district heating benchmarked in Denmark for process heat supply: “Optimisation d'une pompe à chaleur haute température en cascade intégrée au chauffage urbain, référencée au Danemark pour l'approvisionnement en chaleur industrielle: conception thermique et sélection du fluide de travail”","authors":"Mohsen Sadeghi, Tage Petersen, Zhenyu Yang, Benjamin Zühlsdorf, Kim Stenholdt Madsen","doi":"10.1016/j.ijrefrig.2023.12.025","DOIUrl":"https://doi.org/10.1016/j.ijrefrig.2023.12.025","url":null,"abstract":"This work aims to assess and optimize the performance of cascade high-temperature heat pump (HTHP) integrated with district heating (DH) to produce 1 MW steam at 160°C for the industrial processes. The heat available in the primary loop of the DH network at 80 °C is considered as the heat source; which is cooled down 70 °C through the HTHP evaporator, before supplying the DH secondary loop. The use of alternative hydrocarbons in the low-temperature loop are examined; and considering the gas compressor limitation, the HTHP performance of using each refrigerant is optimized and compared to each other.The optimization results reveal that pentane- hydrocarbon with the highest critical temperature- is the most promising refrigerant to be paired with steam in the high-temperature loop, reaching the highest COP of 2.66. However, concerning safety and compressor sizing issues, butane is an excellent candidate; with volumetric heating capacity (VHC) of about two times more than that of pentane, in the expense of just about 4 % reduction in the HTHP COP. In addition, water injection theoretically controls the steam compressor discharge temperature successfully, with just 0.9 K superheating at the compressor outlet; and reduces its power consumption and the HTHP COP up to 4.3 % and 1.7 %, respectively. Moreover, techno-economic analysis demonstrates that the HTHP technology shows a better business case compared to the conventional natural gas and electric boilers.","PeriodicalId":14367,"journal":{"name":"International Journal of Refrigeration","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139029102","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: 0

Real-Time Multi-Variable Optimization of the Interstage Subcooling Vapor-injection Based Transcritical CO2 HPWH: an Integrated Model Predictive Control Approach 基于蒸汽喷射的跨临界二氧化碳 HPWH 级间过冷实时多变量优化：综合模型预测控制方法

International Journal of Refrigeration Pub Date : 2023-12-01 DOI: 10.1016/j.ijrefrig.2023.12.026

Ce Cui, Haowei Xing, Yulong Song, M. Rampazzo, Wenyi Wang, Xiang Yin, Feng Cao

引用次数: 0