This study experimentally validates a configuration integrating heat pipe heat exchangers (HPHEs) on both sides of the evaporator in open refrigerated display cabinets (ORDC), demonstrating significant performance improvements across three standardized ambient conditions (24°C/25°C/28°C, 60% RH). The system achieved a 4.7–10.8% reduction in defrost condensation mass, coupled with 5.9–11.8% lower energy consumption and a 30–40% decrease in compressor cycling frequency. Operational efficiency was enhanced through a 4% extension of refrigeration cycle duration and accelerated product temperature stabilization, which was 6.1% faster with post-stabilization fluctuations constrained within 2.4°C. Thermodynamic analysis confirmed improved heat transfer efficiency, evidenced by an overall heat transfer coefficient of 33.05 W/(m²·K). The integration of HPHEs enables passive precooling and dehumidification of incoming air, significantly suppressing frost formation and optimizing system stability without additional energy input. This research establishes HPHEs as a technically viable solution for achieving substantial energy savings and operational reliability in commercial refrigeration applications.
{"title":"Research on the influence of heat pipes on the performance and frosting characteristics of refrigeration systems in open refrigerated display cabinet","authors":"Pei Yuan, Zheng Gong, Zewen Wang, Fei Tang, Shaojie Wang, Yanli Lu","doi":"10.1016/j.ijrefrig.2026.01.007","DOIUrl":"10.1016/j.ijrefrig.2026.01.007","url":null,"abstract":"<div><div>This study experimentally validates a configuration integrating heat pipe heat exchangers (HPHEs) on both sides of the evaporator in open refrigerated display cabinets (ORDC), demonstrating significant performance improvements across three standardized ambient conditions (24°C/25°C/28°C, 60% RH). The system achieved a 4.7–10.8% reduction in defrost condensation mass, coupled with 5.9–11.8% lower energy consumption and a 30–40% decrease in compressor cycling frequency. Operational efficiency was enhanced through a 4% extension of refrigeration cycle duration and accelerated product temperature stabilization, which was 6.1% faster with post-stabilization fluctuations constrained within 2.4°C. Thermodynamic analysis confirmed improved heat transfer efficiency, evidenced by an overall heat transfer coefficient of 33.05 W/(m²·K). The integration of HPHEs enables passive precooling and dehumidification of incoming air, significantly suppressing frost formation and optimizing system stability without additional energy input. This research establishes HPHEs as a technically viable solution for achieving substantial energy savings and operational reliability in commercial refrigeration applications.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 221-230"},"PeriodicalIF":3.8,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ENOUGH tool is a web-based simulation platform designed to help reducing the carbon footprint of food supply chains while improving product quality. The tool dynamically calculates time-temperature profiles, energy consumption, and greenhouse gas (GHG) emissions across the supply chain. It models key elements such as refrigeration (considering COP, TEWI), transportation (using tonne-kilometre and the GLEC framework), and packaging. It also integrates food quality kinetic models. A significant advantage over traditional life cycle assessments (LCA) is its granular approach and unique incorporation of product quality alongside environmental impacts.
Two examples of case studies demonstrate its utility, highlighting transportation as a major GHG contributor. The first example is based on two scenarios for apple supply chains, with a long-distance imported product that has a higher environmental impact than local varieties. In the second example that focuses on yogurt's last-mile delivery, it is shown that local stores or e-commerce often result in lower emissions due to reduced consumer travel or more efficient logistics.
The objective of the ENOUGH tool is to empower users to identify and implement comprehensive strategies that make food supply systems more sustainable and environmentally friendly.
{"title":"Enough tool: decarbonizing food supply chains while improving product quality","authors":"Denis Leducq , Hong Minh Hoang , Pieter Verboven , Graciela Alvarez","doi":"10.1016/j.ijrefrig.2026.01.005","DOIUrl":"10.1016/j.ijrefrig.2026.01.005","url":null,"abstract":"<div><div>The ENOUGH tool is a web-based simulation platform designed to help reducing the carbon footprint of food supply chains while improving product quality. The tool dynamically calculates time-temperature profiles, energy consumption, and greenhouse gas (GHG) emissions across the supply chain. It models key elements such as refrigeration (considering COP, TEWI), transportation (using tonne-kilometre and the GLEC framework), and packaging. It also integrates food quality kinetic models. A significant advantage over traditional life cycle assessments (LCA) is its granular approach and unique incorporation of product quality alongside environmental impacts.</div><div>Two examples of case studies demonstrate its utility, highlighting transportation as a major GHG contributor. The first example is based on two scenarios for apple supply chains, with a long-distance imported product that has a higher environmental impact than local varieties. In the second example that focuses on yogurt's last-mile delivery, it is shown that local stores or e-commerce often result in lower emissions due to reduced consumer travel or more efficient logistics.</div><div>The objective of the ENOUGH tool is to empower users to identify and implement comprehensive strategies that make food supply systems more sustainable and environmentally friendly.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"184 ","pages":"Pages 159-167"},"PeriodicalIF":3.8,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.ijrefrig.2026.01.002
Sebastiano Tomassetti , Lorenzo Merlonghi , Tomoaki Imai , Giovanni Di Nicola , Chieko Kondou
This study provides 23 two-phase and 133 vapor-phase pressure-specific volume-temperature-composition (pvTz) measurements for the mixture containing carbon dioxide (CO2) and 1,1-difluoroethylene (R1132a), considered a potentially low global warming potential (GWP) alternative for ultralow temperature refrigeration systems. Vapor-liquid equilibrium (VLE) and vapor-phase pvTz properties predicted through molecular dynamics (MD) simulations are also presented. An isochoric apparatus was used to measure the properties for ten CO2 mole fractions along ten isochores with specific volumes equal to (0.016846, 0.018521, 0.028775, 0.029922, 0.029931, 0.032358, 0.037241, 0.039089, 0.052176, 0.083492) m3 kg−1 in the temperature and pressure ranges from (228.15 to 303.15) K and from (404.5 to 2519.9) kPa, respectively. The two-phase measurements were used to assess the VLE of the binary system by the flash method with the Peng-Robinson (PR) and PC-SAFT equations of state (EoSs), yielding average absolute relative deviations (AARDs) between experimental and calculated pressures of 0.20% and 0.19%, respectively. The values calculated with the PR and PC-SAFT EoSs showed qualitative agreement with the VLE properties from MD simulations, yielding AARD(p) of 3.44 % and 3.32 %, respectively. The measurements carried out in the superheated vapor region were compared with calculations from the PR and PC-SAFT EoSs, obtaining low deviations (AARD(p) of 0.38 % for the PR EoS and 0.33 % for the PC-SAFT EoS). Finally, a qualitatively good agreement between the MD simulations and the EoS calculations was also observed in the superheated vapor region (AARD(p) of 1.02 % for the PR EoS and 1.00 % for the PC-SAFT EoS).
{"title":"Experimental measurements and molecular simulations for pvTz properties of carbon dioxide (CO2) + 1,1-difluoroethylene (R1132a) binary system in the two-phase and superheated vapor regions","authors":"Sebastiano Tomassetti , Lorenzo Merlonghi , Tomoaki Imai , Giovanni Di Nicola , Chieko Kondou","doi":"10.1016/j.ijrefrig.2026.01.002","DOIUrl":"10.1016/j.ijrefrig.2026.01.002","url":null,"abstract":"<div><div>This study provides 23 two-phase and 133 vapor-phase pressure-specific volume-temperature-composition (<em>pvTz</em>) measurements for the mixture containing carbon dioxide (CO<sub>2</sub>) and 1,1-difluoroethylene (R1132a), considered a potentially low global warming potential (GWP) alternative for ultralow temperature refrigeration systems. Vapor-liquid equilibrium (VLE) and vapor-phase <em>pvTz</em> properties predicted through molecular dynamics (MD) simulations are also presented. An isochoric apparatus was used to measure the properties for ten CO<sub>2</sub> mole fractions along ten isochores with specific volumes equal to (0.016846, 0.018521, 0.028775, 0.029922, 0.029931, 0.032358, 0.037241, 0.039089, 0.052176, 0.083492) m<sup>3</sup> kg<sup>−1</sup> in the temperature and pressure ranges from (228.15 to 303.15) K and from (404.5 to 2519.9) kPa, respectively. The two-phase measurements were used to assess the VLE of the binary system by the flash method with the Peng-Robinson (PR) and PC-SAFT equations of state (EoSs), yielding average absolute relative deviations (AARDs) between experimental and calculated pressures of 0.20% and 0.19%, respectively. The values calculated with the PR and PC-SAFT EoSs showed qualitative agreement with the VLE properties from MD simulations, yielding AARD(<em>p</em>) of 3.44 % and 3.32 %, respectively. The measurements carried out in the superheated vapor region were compared with calculations from the PR and PC-SAFT EoSs, obtaining low deviations (AARD(<em>p</em>) of 0.38 % for the PR EoS and 0.33 % for the PC-SAFT EoS). Finally, a qualitatively good agreement between the MD simulations and the EoS calculations was also observed in the superheated vapor region (AARD(<em>p</em>) of 1.02 % for the PR EoS and 1.00 % for the PC-SAFT EoS).</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 188-198"},"PeriodicalIF":3.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-05DOI: 10.1016/j.ijrefrig.2026.01.006
Zhouhang Hu , Xuan Yu , Zhenxing Li , Mingsheng Tang , Huiming Zou , Jun Shen
As the core driving component of pulse tube cryocoolers (PTCs), free piston linear compressors are susceptible to piston offset in actual operation, affecting the stroke and performance. This paper employed a magnetic resonance linear compressor (MRLC) to drive PTC, utilizing the magnetic spring effect of magnetic resonance linear motor (MRLM) to suppress piston offset. Through a combination of experimental and finite element analysis (FEA), the paper systematically elucidated the piston offset characteristics of the linear compressor and optimized the MRLM structure. Research shows that piston offset is mainly driven by the mean pressure difference (MPD) between the compression pressure and back pressure. The MRLM exhibits a preload force of 54.1 N at the origin, and the magnetic spring stiffness has a non-symmetrical distribution with low stiffness on the left and high stiffness on the right. The magnetic spring effect in the MRLM, operating similarly to an eccentric spring, suppresses piston offset by utilizing the magnetic spring force at the origin (MSFO) and the asymmetry in magnetic spring stiffness on either side of the origin. The simulation demonstrated that the MRLC can maintain a negative offset of -0.75 mm under high charge pressure of 3.6 MPa, which is significantly lower than that of the Redlich-type linear compressor. Furthermore, by adjusting the dimensions of the linear motor, the MSFO can be regulated to reduce piston offset. This approach provides an alternative design strategy for suppressing piston offset in free piston linear compressors.
{"title":"Research on piston offset suppression and structure optimization for free piston linear compressors in pulse tube cryocoolers","authors":"Zhouhang Hu , Xuan Yu , Zhenxing Li , Mingsheng Tang , Huiming Zou , Jun Shen","doi":"10.1016/j.ijrefrig.2026.01.006","DOIUrl":"10.1016/j.ijrefrig.2026.01.006","url":null,"abstract":"<div><div>As the core driving component of pulse tube cryocoolers (PTCs), free piston linear compressors are susceptible to piston offset in actual operation, affecting the stroke and performance. This paper employed a magnetic resonance linear compressor (MRLC) to drive PTC, utilizing the magnetic spring effect of magnetic resonance linear motor (MRLM) to suppress piston offset. Through a combination of experimental and finite element analysis (FEA), the paper systematically elucidated the piston offset characteristics of the linear compressor and optimized the MRLM structure. Research shows that piston offset is mainly driven by the mean pressure difference (MPD) between the compression pressure and back pressure. The MRLM exhibits a preload force of 54.1 N at the origin, and the magnetic spring stiffness has a non-symmetrical distribution with low stiffness on the left and high stiffness on the right. The magnetic spring effect in the MRLM, operating similarly to an eccentric spring, suppresses piston offset by utilizing the magnetic spring force at the origin (MSFO) and the asymmetry in magnetic spring stiffness on either side of the origin. The simulation demonstrated that the MRLC can maintain a negative offset of -0.75 mm under high charge pressure of 3.6 MPa, which is significantly lower than that of the Redlich-type linear compressor. Furthermore, by adjusting the dimensions of the linear motor, the MSFO can be regulated to reduce piston offset. This approach provides an alternative design strategy for suppressing piston offset in free piston linear compressors.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 326-335"},"PeriodicalIF":3.8,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-03DOI: 10.1016/j.ijrefrig.2026.01.004
Chuang Pan , Shenghao Huang , Yunfeng Qiu , Shuhong Li , Teng Jia , Yanjun Li , Jun Wu , Gui Li
The absorber is a core component of the ammonia-water absorption refrigeration system (AARS). The ultrasonic atomizer can atomize the falling film solution into droplets, which is used to increase the effective mass transfer area between ammonia vapor and the solution. This paper proposes a new type of absorber with an ultrasonic atomizer installed inside the falling film tube and conducts simulation research. The results show that the ammonia absorption amounts of the in-tube parallel atomization absorber (Mode B) and the series atomization absorber (Mode C) are increased by 33.7% and 33.8% respectively. The ultrasonic atomizer significantly improves the absorption effect of the in-tube falling film absorber, which provides a new design idea and theoretical support for improving the performance of the absorber.
{"title":"A new type of absorber based on ultrasonic atomization enhanced in-tube falling film absorption process","authors":"Chuang Pan , Shenghao Huang , Yunfeng Qiu , Shuhong Li , Teng Jia , Yanjun Li , Jun Wu , Gui Li","doi":"10.1016/j.ijrefrig.2026.01.004","DOIUrl":"10.1016/j.ijrefrig.2026.01.004","url":null,"abstract":"<div><div>The absorber is a core component of the ammonia-water absorption refrigeration system (AARS). The ultrasonic atomizer can atomize the falling film solution into droplets, which is used to increase the effective mass transfer area between ammonia vapor and the solution. This paper proposes a new type of absorber with an ultrasonic atomizer installed inside the falling film tube and conducts simulation research. The results show that the ammonia absorption amounts of the in-tube parallel atomization absorber (Mode B) and the series atomization absorber (Mode C) are increased by 33.7% and 33.8% respectively. The ultrasonic atomizer significantly improves the absorption effect of the in-tube falling film absorber, which provides a new design idea and theoretical support for improving the performance of the absorber.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 81-94"},"PeriodicalIF":3.8,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-03DOI: 10.1016/j.ijrefrig.2026.01.003
S. Zebbar, D. Zebbar, Z. Rahmani
This paper details a computational fluid dynamics (CFD) simulation applied to the evaporator of a diffusion absorption refrigeration (DAR) system, using a water-ammonia mixture as the working fluid and helium as an auxiliary gas. Although hydrogen is traditionally preferred in DAR systems due to its favorable properties for separation in the absorber and enhanced mass transfer, its high flammability imposes safety constraints. Therefore, to address these concerns and improve system efficiency, helium is considered a safer alternative, particularly for high-power units. Moreover, building on a previously validated numerical model of the evaporator in CONVERGE CFD with the Reynolds-Averaged Navier-Stokes (RANS) approach, this study investigates the evaporator’s behavior across operating pressures of 10–25 bar, aiming to determine the optimal pressure when helium is used as the auxiliary gas.
A series of simulations were performed for total pressure values ranging from 10 to 25 bar. The findings indicate that lower total pressures result in reduced evaporation temperatures across the evaporator, leading to improved evaporation and heat transfer efficiency. Notably, a total pressure of 10-12 bar is identified as optimal for maximizing cooling capacity when helium is used as the auxiliary gas in a water-ammonia DAR system. These findings underscore the potential of helium in solar-driven absorption–diffusion refrigeration systems, despite its scarcity and high cost, particularly under the limited thermal input characteristic of renewable sources. The results indicate that helium’s unique properties make it an attractive option for enhancing both safety and efficiency, with the DAR system performing noticeably better when operated with helium than with hydrogen.
以水-氨混合物为工作流体，氦气为辅助气体，对扩散吸收式制冷（DAR）系统蒸发器进行了计算流体力学（CFD）模拟。传统上，氢气是DAR系统的首选，因为它在吸收器中具有良好的分离性能和增强的传质性，但其高可燃性限制了安全性。因此，为了解决这些问题并提高系统效率，氦气被认为是一种更安全的替代品，特别是对于大功率装置。此外，基于先前在CONVERGE CFD中使用reynolds - average Navier-Stokes （RANS）方法验证的蒸发器数值模型，本研究研究了蒸发器在10-25 bar工作压力下的行为，旨在确定使用氦气作为辅助气体时的最佳压力。对10 ~ 25bar的总压力值进行了一系列模拟。研究结果表明，较低的总压力会降低蒸发器的蒸发温度，从而提高蒸发和传热效率。值得注意的是，当在水-氨雷达系统中使用氦气作为辅助气体时，总压力为10-12 bar被认为是冷却能力最大化的最佳选择。这些发现强调了氦在太阳能驱动的吸收-扩散制冷系统中的潜力，尽管其稀缺和高成本，特别是在可再生能源有限的热输入特性下。结果表明，氦气的独特性质使其成为提高安全性和效率的有吸引力的选择，在使用氦气时，DAR系统的性能明显优于使用氢气时。
{"title":"CFD analysis of an evaporator in diffusion absorption refrigeration systems using helium as an auxiliary gas","authors":"S. Zebbar, D. Zebbar, Z. Rahmani","doi":"10.1016/j.ijrefrig.2026.01.003","DOIUrl":"10.1016/j.ijrefrig.2026.01.003","url":null,"abstract":"<div><div>This paper details a computational fluid dynamics (CFD) simulation applied to the evaporator of a diffusion absorption refrigeration (DAR) system, using a water-ammonia mixture as the working fluid and helium as an auxiliary gas. Although hydrogen is traditionally preferred in DAR systems due to its favorable properties for separation in the absorber and enhanced mass transfer, its high flammability imposes safety constraints. Therefore, to address these concerns and improve system efficiency, helium is considered a safer alternative, particularly for high-power units. Moreover, building on a previously validated numerical model of the evaporator in CONVERGE CFD with the Reynolds-Averaged Navier-Stokes (RANS) approach, this study investigates the evaporator’s behavior across operating pressures of 10–25 bar, aiming to determine the optimal pressure when helium is used as the auxiliary gas.</div><div>A series of simulations were performed for total pressure values ranging from 10 to 25 bar. The findings indicate that lower total pressures result in reduced evaporation temperatures across the evaporator, leading to improved evaporation and heat transfer efficiency. Notably, a total pressure of 10-12 bar is identified as optimal for maximizing cooling capacity when helium is used as the auxiliary gas in a water-ammonia DAR system. These findings underscore the potential of helium in solar-driven absorption–diffusion refrigeration systems, despite its scarcity and high cost, particularly under the limited thermal input characteristic of renewable sources. The results indicate that helium’s unique properties make it an attractive option for enhancing both safety and efficiency, with the DAR system performing noticeably better when operated with helium than with hydrogen.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 95-107"},"PeriodicalIF":3.8,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Corrigendum to ‘Numerical and experimental evaluation of the thermal and dynamic performance of a phase change material in an indirect solar dryer’ International Journal of Refrigeration 174 (2025) 98–110","authors":"Dounia Chaatouf , Mourad Salhi , Abir Bria , Benyounes Raillani , Samir Amraqui , Ahmed Mezrhab","doi":"10.1016/j.ijrefrig.2025.12.037","DOIUrl":"10.1016/j.ijrefrig.2025.12.037","url":null,"abstract":"","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Page 454"},"PeriodicalIF":3.8,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Portable air conditioners are popular for their convenience, high efficiency, and installation-free design. However, their unique structures present challenges, including drainage, heat dissipation, and limited energy efficiency, especially in condensate removal. Water wheel atomization (WWA) is often used to improve energy efficiency by evaporating condensate, but its effectiveness is limited, especially in high humidity, which can affect long-term operation. Building on our previous work on spray tube atomization (STA) for condensate removal, this paper compares the performance of different atomization methods in portable air conditioners. It highlights STA's advantages over WWA and its practical feasibility. Comparative experiments show a direct link between energy/exergy efficiency and condensate evaporation intensity. With its higher evaporation intensity, STA offers clear advantages in both energy/exergy efficiency and condensate removal. Under the rated conditions for condensate removal (27 °C/ 90%), STA outperformed other methods. Compared to air cooling (AC), STA increased cooling capacity by 13.2%, reduced power consumption by 7.8%, and improved the Energy Efficiency Ratio (EER) by 11.7%. To validate the results, we examined the effects of ambient temperature and humidity on STA, WWA, and AC. STA consistently outperformed the others.
{"title":"Energy and exergy analysis of the portable air conditioner with different atomization methods","authors":"Hui Chen , Jiaxin Yun , Siyu Wu, Changjiajin Huang, Yingwen Liu","doi":"10.1016/j.ijrefrig.2025.12.039","DOIUrl":"10.1016/j.ijrefrig.2025.12.039","url":null,"abstract":"<div><div>Portable air conditioners are popular for their convenience, high efficiency, and installation-free design. However, their unique structures present challenges, including drainage, heat dissipation, and limited energy efficiency, especially in condensate removal. Water wheel atomization (WWA) is often used to improve energy efficiency by evaporating condensate, but its effectiveness is limited, especially in high humidity, which can affect long-term operation. Building on our previous work on spray tube atomization (STA) for condensate removal, this paper compares the performance of different atomization methods in portable air conditioners. It highlights STA's advantages over WWA and its practical feasibility. Comparative experiments show a direct link between energy/exergy efficiency and condensate evaporation intensity. With its higher evaporation intensity, STA offers clear advantages in both energy/exergy efficiency and condensate removal. Under the rated conditions for condensate removal (27 °C/ 90%), STA outperformed other methods. Compared to air cooling (AC), STA increased cooling capacity by 13.2%, reduced power consumption by 7.8%, and improved the Energy Efficiency Ratio (EER) by 11.7%. To validate the results, we examined the effects of ambient temperature and humidity on STA, WWA, and AC. STA consistently outperformed the others.</div></div>","PeriodicalId":14274,"journal":{"name":"International Journal of Refrigeration-revue Internationale Du Froid","volume":"183 ","pages":"Pages 49-64"},"PeriodicalIF":3.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.ijrefrig.2026.01.001
Nima Irannezhad , Rasool Mohammadi , Luisa Rossetto , Andrea Diani
The impact of inclination on flow boiling inside a 7 mm outer diameter microfin tube is experimentally investigated and visualized for the low global warming refrigerant R515B. The heat transfer coefficient is evaluated at mass fluxes of 50, 100, 200, and 400 kg m–2 s–1, heat fluxes of 10, 30, and 50 kW m–2, at the saturation temperature of 30 °C, for vapor qualities ranging from 0.1 to 0.9. The investigated inclinations vary from +60° to –60° including the horizontal one. Under conditions of nucleate boiling dominance with the absence of strong convective boiling, the downward configurations experience an elevation of the heat transfer coefficient while the upward configurations have a lower heat transfer coefficient. Increasing the mass flux and heat flux to 400 kg m–2 s–1 and 50 kW m–2 nullifies the effect of inclination for all inclinations except for –60°. A noteworthy aspect with respect to –60° was the occurrence of thermal crisis at high vapor qualities, a unique phenomenon that did not occur at other inclinations at similar operating conditions, which was ascribed to the nature of the flow patterns. Two correlations (Irannezhad et al. (2024) and Mehendale (2017)) developed for flow boiling inside horizontal microfin tube were compared with the results which resulted in mean absolute error of 21.4% and 25.2% respectively. A dimensionless parameter, which is correlated with inclination factor (IF) was proposed, which could be utilized for further studies as a tool to predict the heat transfer coefficients for various inclinations.
采用低全球变暖制冷剂R515B，实验研究了倾角对7 mm外径微鳍管内流动沸腾的影响。在饱和温度为30°C时，质量通量为50、100、200和400 kg m-2 s-1，热通量为10、30和50 kW m-2，蒸汽质量范围为0.1至0.9时，传热系数进行了评估。所研究的倾角从+60°到-60°不等，包括水平倾角。在没有强对流沸腾的条件下，有核沸腾占主导地位，向下配置的传热系数升高，向上配置的传热系数降低。将质量通量和热通量增加到400 kg - m-2 s-1和50 kW - m-2，可以消除除-60°以外的所有倾角的倾角影响。关于-60°的一个值得注意的方面是在高蒸气质量下发生热危机，这是一种独特的现象，在类似的操作条件下，在其他倾角下不会发生，这归因于流动模式的性质。对水平微鳍管内流动沸腾的两种相关性（Irannezhad et al.（2024）和Mehendale(2017)）的结果进行比较，平均绝对误差分别为21.4%和25.2%。提出了一个与倾角因子（IF）相关的无量纲参数，该参数可作为预测不同倾角下换热系数的工具，为进一步研究提供依据。
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Pub Date : 2025-12-31DOI: 10.1016/j.ijrefrig.2025.12.035
Ali M. Ashour , Osama B. Ahmed , Saif Ali Kadhim , Adrián Mota-Babiloni , Farhan Lafta Rashid , Abdallah Bouabidi , Kaouther Ghachem , Walid Aich
Refrigeration systems are essential in daily life. However, increasing cooling demand requires developing more efficient systems with lower environmental footprints. The integration of a thermoelectric cooler with vapor compression refrigeration systems has recently attracted attention as a practical means to improve subcooling and enhance overall performance. The present study experimentally and predictively assesses a VCR system with thermoelectric subcooling (VCR-TECS) for several low-global warming potential (GWP) refrigerants. The VCR system was improved by attaching thermoelectric modules to the condenser outlet, and tests were performed at voltages ranging from 1 to 10 V and water flow rates of 1 to 3 L/min. The introduction of thermoelectric subcooling raised evaporator cooling capacity to 8% and improved the system COP by 5-7% at moderate voltages (4-6 V). Three statistical models (Random Forest, Gradient Boosting, and Linear Regression) were developed using experimental data and validated. This was the best performance by Gradient Boosting, with an R² of more than 0.996 and an RMSE of 0.02, effectively reproducing the nonlinear trends in performance. The proposed optimization is a score-based multi-objective one that maximizes cooling capacity and COP, and minimizes total power input to determine the optimal operating conditions. Maximum unified scores were obtained by R513A (0.37) and R1234yf (0.36) at 4 V, which is an improvement in the performance of 35-40 % as compared with other refrigerants. In summary, the VCR-TECS structure offers a novel, simple, efficient, and environmentally friendly approach to improve refrigeration performance during low-voltage operation.
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