Article
Thermodynamics
Kishor Deshmukh, Suhas Karmare, Pradeep Patil
Summary: The convective heat transfer performance of U-pipe evacuated tube solar thermal collector with TiN nanofluid was investigated in this study. TiN nanoparticles with sizes of 40-50 nm were dispersed in distilled water at different volume concentrations. The stability and thermophysical properties of TiN nanofluid were experimentally measured. The experimental investigation included the convective heat transfer coefficient, friction factor characteristic, and solar thermal efficiency at different volume concentrations and mass flow rates. The performance of the solar thermal collector was tested under outdoor conditions. A correlation was proposed to determine the Nusselt number, friction factor, and solar thermal efficiency in laminar flow. The TiN nanofluid was recommended for industrial solar thermal applications due to its notable improvement in convective heat transfer performance despite the friction factor penalty.
APPLIED THERMAL ENGINEERING
(2023)
Article
Green & Sustainable Science & Technology
Virendra Vishnu Bhagwat, Sujit Roy, Biplab Das, Nikhilkumar Shah, Avijit Chowdhury
Summary: This study investigated the performance of a heat pipe assisted parabolic trough collector with paraffin wax based phase change material for solar energy storage. The experiment was conducted in North-East India, comparing the system with and without circular fins in the heat pipe evaporator section. The presence of fins improved both charging and discharging efficiency of the latent heat storage system.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2021)
Article
Thermodynamics
Feng Yi, Yunhua Gan, Zhifeng Xin, Yong Li, Hanyin Chen
Summary: In this study, a novel double-layer wick structure consisting of sintered copper powder and spiral woven mesh was proposed to improve the thermal performance of ultra-thin heat pipes. The results showed that the double-layer wick structure exhibited an 11.1% increase in ultimate power compared to the single wick structure.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Hong-Jin Joo, Hee-Youl Kwak, Minsuk Kong
Summary: The present study experimentally investigates the effect of twisted tape inserts on the thermal performance of an eccentric inlet and outlet heat pipe evacuated-tube solar thermal collector (HP-ESTC). The results show that the addition of twisted tape inserts enhances heat transfer performance by eliminating stagnation flow, reducing flow skewness, and generating rotating flow. A comprehensive performance analysis considering both heat transfer and pressure drop characteristics confirms that using twisted tape inserts can improve overall performance by approximately 7.7%. To assess its applicability for commercial HP-ESTCs, an HP-ESTC containing twisted tape inserts was manufactured and tested outdoors.
Article
Thermodynamics
Prem Kumar, Mayur Gachake, Sameer Khandekar
Summary: The study focuses on reducing heat leak in loop heat pipes (LHP) by manipulating the properties of the copper wick, leading to improved thermal performance. It was found that the oxidized copper wick performs better thermally than the pure copper wick, attributed to the lower thermal conductivity of the oxidized porous wick reducing heat leak.
APPLIED THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
T. Zhang, Y. F. Zhang, Z. R. Shi, Q. F. Li, J. Y. Cai
Summary: A hybrid PV/T collector/evaporator was designed and a hybrid system named PV-SAHP/GHP was proposed. Outdoor experiments were conducted to compare the operating characteristics of different modes. The results showed that the GHP-PV/T mode had satisfactory energy-saving effect while the PV-SAHP mode met the temperature demand but had unsatisfactory energy conservation effect. It is recommended to operate the GHP-PV/T mode during intense radiation and the PV-SAHP mode otherwise to balance the thermal performance and energy-saving benefits.
Review
Thermodynamics
Jasinta Poonam Ekka, Disha Dewangan
Summary: Solar energy provides a sustainable solution to meet the increasing energy demand and address environmental concerns. Researchers have integrated heat pipes into solar collectors to improve their efficiency. This integration has various applications and offers improved performance, especially in high-temperature applications.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Hao Guo, Xianbing Ji, Yuanyuan Gan, Jinliang Xu
Summary: Particle morphology and wettability of porous wick have significant effects on the heat transfer performance of loop heat pipes (LHPs). The capillary performance of dendritic particle wick is better than that of spherical particle wick, and superhydrophilic wick has a higher climbing height compared to hydrophilic wick. The particle morphology also affects the uniformity of the working fluid distribution and the operating temperature of LHPs.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Review
Thermodynamics
Hong Li, Hongyuan Liu, Min Li
Summary: This paper provides a comprehensive overview of heat pipe based solar collectors (HP-SCs), summarizing their classification, performance evaluation and optimization, and effective improvements. It discusses the common features and relationships between HP-STCs and HP-PV/T technology. The paper concludes with remarks on application situations, performance analysis and comparison, and identifies new research directions and potentials in this field.
Article
Thermodynamics
Bagher Omidi, Nader Rahbar, Hadi Kargarsharifabad, Zahra Poolaei Moziraji
Summary: This study investigated a hybrid system that utilizes renewable energy to generate hot water and distilled water. The system uses a parabolic-trough heat pipe solar collector to produce hot water and provide drinking water. By increasing the temperature of the evaporator area and the condenser of the heat pipe, the system is able to directly connect to the desalination system's saltwater tank. The study evaluated the effects of water flow rate, number of heat pipes, and the filling porous medium of the vacuum tube on the system performance.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Energy & Fuels
A. Allouhi, M. Benzakour Amine
Summary: This study aims to characterize the performance of a heat pipe flat plate solar collector using different nanofluids, with CuO-based nanofluid showing the highest enhancements in energetic and exergetic efficiencies. The decrease in specific heat of nanofluids is identified as the main thermal property responsible for performance improvement.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Green & Sustainable Science & Technology
Sana Said, Sofiene Mellouli, Talal Alqahtani, Salem Algarni, Ridha Ajjel, Kaouther Ghachem, Lioua Kolsi
Summary: An experimental study evaluated the thermal performance of different types of evacuated tube solar collectors (ETSCs) for water heating. The results showed that the ETSC system performed well at higher solar irradiance and lower water flow rates. Furthermore, the helical tube-based ETSC demonstrated a higher thermal efficiency compared to other configurations, making it a promising heat exchanger for ETSCs.
Article
Thermodynamics
Shwin-Chung Wong, Mao-Shen Deng
Summary: Two types of novel triple composite mesh-groove-powder wicks were proposed and tested in a flat-plate heat pipe. The results showed that the powders in the mesh-groove evaporator increased flow resistance and caused partial dry-out in some grooves at high heat loads, but the powder-only evaporator improved the heat load.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Review
Engineering, Mechanical
N. Jayanthi, M. Venkatesh, R. Suresh Kumar, S. Sekar
Summary: Solar energy is abundantly available and widely utilized for various applications, with solar collectors being a fundamental tool in harnessing this energy. The efficiency of solar collectors can be enhanced by using heat pipes and nanofluids, which have been the subject of recent research to improve the working efficiency of heat pipe solar collectors.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING
(2021)
Article
Energy & Fuels
Moucun Yang, Liming Zhi, Kelong Diao, Yuezhao Zhu, Robert A. Taylor
Summary: A new solar collector was designed for producing mid-temperature heat, with a unique structure and coating. Genetic algorithm was used to optimize the collector's parameters, and theoretical and numerical analysis were conducted for its optical and thermal performance. The results showed that the collector had an optical efficiency of 57.6% and a thermal efficiency of 30.6% at 250 degrees C.
