The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform

Yao-hua Zhao - One of the best experts on this subject based on the ideXlab platform.

  • numerical and experimental investigations of latent thermal energy storage device based on a flat Micro Heat Pipe array metal foam composite structure
    Renewable Energy, 2020
    Co-Authors: Lin Liang, Y H Diao, Yao-hua Zhao, Zeyu Wang, Fanfei Bai
    Abstract:

    Abstract Latent Heat thermal energy storage (LHTES) is crucial in the application of renewable energy and waste Heat recovery. A novel LHTES device with a flat Micro-Heat Pipe array (FMHPA)–metal foam composite structure is designed in this study to obtain excellent Heat transfer performance. An evaluation standard called integrated power is proposed to assess and compare the structural advantages of the LHTES device with others. Performances of FMHPA, temperature distribution, effort of inlet temperature and velocity of Heat transfer fluid (HTF) are also studied in the experiments. A three-dimensional numerical model is developed to investigate the effort of porosity and pore density of metal foam on the charging process. Results show that the FMHPA–copper foam composite structure improves the performance of the LHTES device. This structure exhibits stronger Heat transfer performance than that of other devices. The increasing inlet temperature of HTF has a better promotion effect on power than raising HTF velocity. High porosity is conducive to natural convection but detrimental to Heat conduction. High pore density is disadvantageous to natural convection and does not affect Heat conduction.

  • thermal performance of integrated collector storage solar air Heater with evacuated tube and lap joint type flat Micro Heat Pipe arrays
    Applied Energy, 2020
    Co-Authors: Zeyu Wang, Yan-hua Diao, Yao-hua Zhao, Lin Liang, Chuanqi Chen, Tengyue Wang
    Abstract:

    Abstract To alleviate the problem of global warming and the energy crisis, this study proposed an integrated collector storage solar air Heater that uses evacuated tubes as solar absorbers and paraffin as thermal storage material. In the proposed unit, lap joint-type flat Micro-Heat Pipe arrays serve as Heat conductors that transmit the solar energy absorbed by the evacuated tubes to the thermal storage tank or transfer the Heat stored in the tank to the air flow channel. Outdoor experiments were carried out to obtain the thermal performance of the proposed device during charging and discharging. The effects of weather conditions, supply air flow rates, and inlet temperature on the thermal response of the integrated collector storage solar air Heater were reported. The thermal storage efficiency during the experiment period ranged from 56.1% to 67.5% when the mean outdoor temperature ranged from −5.7 °C to 36.2 °C. The mean thermal extraction power and thermal released efficiency reached 1268.8 W and 98.5%, respectively. The results of the energy conversion process analysis and mathematical fitting showed that the mean charging efficiency was linear with the normalized temperature difference. The mean outlet temperature and mean extraction power were linear with the inlet temperature and exponential with the air flow rate. A conceptual design of an air Heating system using the integrated collector storage solar air Heater for a 9.9 m2 building was presented. The benefit pre-evaluation revealed that the system can reduce carbon emissions by approximately 5.8 tons over its life cycle.

  • thermal performance and energy saving analysis of indoor air water Heat exchanger based on Micro Heat Pipe array for data center
    Energies, 2020
    Co-Authors: Heran Jing, Zhenhua Quan, Lincheng Wang, Yao-hua Zhao, Ruyang Ren, Zichu Liu
    Abstract:

    According to the temperature regulations and high energy consumption of air conditioning (AC) system in data centers (DCs), natural cold energy becomes the focus of energy saving in data center in winter and transition season. A new type of air–water Heat exchanger (AWHE) for the indoor side of DCs was designed to use natural cold energy in order to reduce the power consumption of AC. The AWHE applied Micro-Heat Pipe arrays (MHPAs) with serrated fins on its surface to enhance Heat transfer. The performance of MHPA-AWHE for different inlet water temperatures, water and air flow rates was investigated, respectively. The results showed that the maximum efficiency of the Heat exchanger was 81.4% by using the effectiveness number of transfer units (e-NTU) method. When the max air flow rate was 3000 m3/h and the water inlet temperature was 5 °C, the maximum Heat transfer rate was 9.29 kW. The maximum pressure drop of the air side and water side were 339.8 Pa and 8.86 kPa, respectively. The comprehensive evaluation index j/f1/2 of the MHPA-AWHE increased by 10.8% compared to the plate–fin Heat exchanger with louvered fins. The energy saving characteristics of an example DCs in Beijing was analyzed, and when the air flow rate was 2500 m3/h and the number of MHPA-AWHE modules was five, the minimum payback period of the MHPA-AWHE system was 2.3 years, which was the shortest and the most economical recorded. The maximum comprehensive energy efficiency ratio (EER) of the system after the transformation was 21.8, the electric power reduced by 28.3% compared to the system before the transformation, and the control strategy was carried out. The comprehensive performance provides a reference for MHPA-AWHE application in data centers.

  • performance of a flat plate Micro Heat Pipe at different filling ratios and working fluids
    Applied Thermal Engineering, 2019
    Co-Authors: Gang Wang, Zhenhua Quan, Yao-hua Zhao, Hongyan Wang
    Abstract:

    Abstract An experiment was carried out to study the effect of liquid filling ratio, inclination angle, and type of working fluid on the performance of a novel flat-plate Micro Heat Pipe (FPMHP). The FPMHP is developed based on a multiport Micro/minichannel flat tube, capable of the advantages such as the simple manufacturing process, flexible structure, good isothermal performance and Heat transport with a long distance. Results shows that a filling ratio has a significant effect on thermal performance, and a FPMHP with a filling ratio of 20% has the best performance. The temperature distribution along the adiabatic section showed nearly no difference between two measuring points, indicating that the FPMHP is able to employed as a high-efficiency Heat transfer equipment of phase change. FPMHP performance was improved remarkably when the inclination angle increased from 0° to 20° due to the effect of gravitational and buoyancy force, but the performance difference was negligible when the inclination angle increased from 20° to 90°. For different working fluids, the higher transmission factor, the better working fluids thermal performance. Thus, the FPMHP using methanol has the best performance, with a minimum thermal resistance of 0.18 K/W and a maximum thermal conductivity of 8539 W/mK, respectively.

  • Thermal Performance of a Low-Temperature Heat Exchanger Using a Micro Heat Pipe Array
    MDPI AG, 2019
    Co-Authors: Jingang Yang, Yao-hua Zhao, Aoxue Che, Zhenhua Qua
    Abstract:

    Domestic Heat exchangers, even though widely used in industry, are not adequate for studies on low-temperature flue-gas use technologies. Despite spite their limitations, very few theoretical models have been investigated based on practical applications. Moreover, most of the existing studies on Heat exchangers have focused particularly on one-dimensional and two-dimensional Heat transfer models, while limited studies focus on three-dimensional ones. Therefore, this study aims at investigating the thermal performance of a low-temperature flue-gas Heat recovery unit in the cold regions. Specifically, this study was conducted in the context of Changchun of Jilin Province, China, a city with the mean ambient temperature of −14 °C and mean diurnal temperature of −10 °C during winter. Experimental results showed that the thermal efficiency of the Heat exchanger was higher than 60%. Through assessing the Heat exchange coefficient and Heat exchange efficiency of the Heat exchanger, it is found that the thermal efficiency had been improved up to 0.77⁻0.83. Furthermore, the ICEPAK software and the standard k-ε RNG turbulence model were used to carry out simulations. The velocity and outlet temperature of fresh airflow and polluted airflow were simulated through setting different inlet temperatures of fresh air and polluted air inlet. Numerical results further indicated that the flow state was laminar flow. The Micro Heat Pipe array side had small eddies and the Heat transfer was significantly improved due to the flow of air along the surface of the Micro Heat Pipe

Zhenhua Quan - One of the best experts on this subject based on the ideXlab platform.

  • thermal performance and energy saving analysis of indoor air water Heat exchanger based on Micro Heat Pipe array for data center
    Energies, 2020
    Co-Authors: Heran Jing, Zhenhua Quan, Lincheng Wang, Yao-hua Zhao, Ruyang Ren, Zichu Liu
    Abstract:

    According to the temperature regulations and high energy consumption of air conditioning (AC) system in data centers (DCs), natural cold energy becomes the focus of energy saving in data center in winter and transition season. A new type of air–water Heat exchanger (AWHE) for the indoor side of DCs was designed to use natural cold energy in order to reduce the power consumption of AC. The AWHE applied Micro-Heat Pipe arrays (MHPAs) with serrated fins on its surface to enhance Heat transfer. The performance of MHPA-AWHE for different inlet water temperatures, water and air flow rates was investigated, respectively. The results showed that the maximum efficiency of the Heat exchanger was 81.4% by using the effectiveness number of transfer units (e-NTU) method. When the max air flow rate was 3000 m3/h and the water inlet temperature was 5 °C, the maximum Heat transfer rate was 9.29 kW. The maximum pressure drop of the air side and water side were 339.8 Pa and 8.86 kPa, respectively. The comprehensive evaluation index j/f1/2 of the MHPA-AWHE increased by 10.8% compared to the plate–fin Heat exchanger with louvered fins. The energy saving characteristics of an example DCs in Beijing was analyzed, and when the air flow rate was 2500 m3/h and the number of MHPA-AWHE modules was five, the minimum payback period of the MHPA-AWHE system was 2.3 years, which was the shortest and the most economical recorded. The maximum comprehensive energy efficiency ratio (EER) of the system after the transformation was 21.8, the electric power reduced by 28.3% compared to the system before the transformation, and the control strategy was carried out. The comprehensive performance provides a reference for MHPA-AWHE application in data centers.

  • performance of a flat plate Micro Heat Pipe at different filling ratios and working fluids
    Applied Thermal Engineering, 2019
    Co-Authors: Gang Wang, Zhenhua Quan, Yao-hua Zhao, Hongyan Wang
    Abstract:

    Abstract An experiment was carried out to study the effect of liquid filling ratio, inclination angle, and type of working fluid on the performance of a novel flat-plate Micro Heat Pipe (FPMHP). The FPMHP is developed based on a multiport Micro/minichannel flat tube, capable of the advantages such as the simple manufacturing process, flexible structure, good isothermal performance and Heat transport with a long distance. Results shows that a filling ratio has a significant effect on thermal performance, and a FPMHP with a filling ratio of 20% has the best performance. The temperature distribution along the adiabatic section showed nearly no difference between two measuring points, indicating that the FPMHP is able to employed as a high-efficiency Heat transfer equipment of phase change. FPMHP performance was improved remarkably when the inclination angle increased from 0° to 20° due to the effect of gravitational and buoyancy force, but the performance difference was negligible when the inclination angle increased from 20° to 90°. For different working fluids, the higher transmission factor, the better working fluids thermal performance. Thus, the FPMHP using methanol has the best performance, with a minimum thermal resistance of 0.18 K/W and a maximum thermal conductivity of 8539 W/mK, respectively.

  • Experimental study on Heat dissipation for lithium-ion battery based on Micro Heat Pipe array (MHPA)
    Applied Thermal Engineering, 2018
    Co-Authors: Xin Ye, Yao-hua Zhao, Zhenhua Quan
    Abstract:

    Abstract Safe containment and management of appreciable Heat effects associated with lithium-ion (Li-ion) batteries in high-power applications remain a challenge before widespread commercialization can occur. In this study, experiments utilizing Li-ion battery packs were conducted under sealed conditions with constant current of 18 A. Temperatures were measured with and without Micro Heat Pipe arrays (MHPAs) during the charge–discharge cycle. The temperature results of the Li-ion battery packs validated the effectiveness of the cooling system based on MHPAs in lowering the temperature increase rate of battery packs at 1C rate and minimizing the temperature difference inside battery packs and cells during operation. Based on the experimental data, the Heat generation and dissipation of Li-ion battery pack are analyzed. The results of experiments and calculation revealed enhanced stability and safety of battery during the continuous charge–discharge cycle. This novel MHPA based on a cooling system possessed the characteristics of high energy efficiency, an easy-to-manufacture process and compactness.

  • thermal management system of lithium ion battery module based on Micro Heat Pipe array
    International Journal of Energy Research, 2018
    Co-Authors: Yao-hua Zhao, Zhenhua Quan
    Abstract:

    Summary Temperature affects the performance of electric vehicle battery. To solve this problem, Micro Heat Pipe arrays are utilized in a thermal management system that cools and Heats battery modules. In the present study, the Heat generation of a battery module during a charge-discharge cycle under a constant current of 36 A (2C) was computed. Then, the cooling area of the condenser was calculated and experimentally validated. At rates of 1C and 2C, the thermal management system effectively reduced the temperature of the module to less than 40°C, and the temperature difference was controlled less than 5°C between battery surfaces of the module. A Heating plate with 30-W power effectively improved charge performance at low temperature within a short Heating time and with uniform temperature distribution. Charge capacity obviously increased after Heating when battery temperature was below 0°C. This study presents a new way to enhance the stability and safety of a battery module during the continuous charge-discharge cycle at high temperatures and low temperatures accordingly.

  • experimental investigation and performance evaluation of a vacuum tube solar air collector based on Micro Heat Pipe arrays
    Journal of Cleaner Production, 2017
    Co-Authors: Ting Ting Zhu, Y H Diao, Feng-fei Li, Yao-hua Zhao, Zhenhua Quan
    Abstract:

    Abstract An experimental study was conducted to evaluate the thermal performance of a vacuum tube solar air collector that is based on Micro Heat Pipe arrays (MHPA) and features wavelike fins attached to the condenser section of the MHPA. The experimental results were used to analyze the thermal performance of the collector, particularly the temperature distribution in the different localizations of the air collector. The Heat loss analysis provided a useful parameter to evaluate the Heat loss of the collector. Results showed that a decrease in the inlet, will led to an increase in efficiency because of the reduced Heat losses to the environment. The daily thermal efficiency varied between 50% and 70%. In the performance analysis of the MHPA collector, varying flow rates were employed to observe the change in efficiency, outlet temperature, MHPA temperature behavior variation vs. solar radiation, and air flow rate. The utilization of the collector can reduce the amount of emissions of gaseous waste emissions, which has large energy saving potential and environmental benefits. The proposed MHPA-based vacuum tube solar air collector shows good potential in large-scale applications, such as in the room Heating of farmhouses, industrial buildings, and remote outposts, as well as in the agricultural sector.

Ting Ting Zhu - One of the best experts on this subject based on the ideXlab platform.

  • experimental study on an integrated collector storage solar air Heater based on flat Micro Heat Pipe arrays
    Energy and Buildings, 2017
    Co-Authors: Zeyu Wang, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Lin Liang, F W Bai
    Abstract:

    Abstract This study investigated the performance of an integrated collector storage solar air Heater based on latent Heat storage and flat Micro-Heat Pipe arrays. The structure and working principle of the device were explained in detail. The effective area of the collector is 0.93 m 2 , and the mass of the phase change material (PCM) is 45.8 kg. An integrated collector storage experimental system was set up, and outdoor experiments were conducted to demonstrate the feasibility of the device for energy storage and air Heating. The temperature distribution of the PCM was recorded during charging and discharging to monitor the propagation of the melting and freezing front. Efficiency and power during charging and discharging were also calculated. The integrative device exhibited 59% and 91.6% efficiencies for solar air charging and discharging at 393 and 344 W power, respectively.

  • thermal performance of solar air collection storage system with phase change material based on flat Micro Heat Pipe arrays
    Energy Conversion and Management, 2017
    Co-Authors: Tengyue Wang, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Jing Liu, Xiangqian Wei
    Abstract:

    Abstract In this study, a new type of solar air collection-storage thermal system (ACSTS) with phase change material (PCM) is designed using flat Micro-Heat Pipe arrays (FMHPA) as the Heat transfer core element. The solar air collector comprises FMHPA and vacuum tubes. The latent thermal storage device (LTSD) utilizes lauric acid, which is a type of fatty acid, as PCM. The experiments test the performance of collector efficiency and charging and discharging time of thermal storage device through different air volume flow rates. After a range of tests, high air volume flow rate is concluded to contribute to high collector efficiency and short charging and discharging time and enhance instantaneous Heat transfer, whereas an air volume flow rate of 60 m 3 /h during discharging provides a steady outlet temperature. The cumulative Heat transfer during discharging is between 4210 and 4300 kJ.

  • performance evaluation of a novel flat plate solar air collector with Micro Heat Pipe arrays mhpa
    Applied Thermal Engineering, 2017
    Co-Authors: Ting Ting Zhu, Yan-hua Diao, Yao-hua Zhao
    Abstract:

    Abstract This paper proposes a new type of a flat-plate solar air collector (SAC) with Micro-Heat Pipe arrays (MHPA), which consist of a Heat collection and transfer section and an air ventilation and Heat exchange section. In the unique structure, the Heat exchange of air is separated from Heat collection and transmission. This work experimentally and theoretically investigates the Heat transfer and friction factor characteristics of the proposed MHPA-flat plate solar air collector. Numerical simulation and experimental results are compared to show the instantaneous performance of the collector under quasi-steady state conditions. Efficiency, time constant, inlet temperature, outlet temperature, absorber temperature, and glass cover temperature are obtained. The effects of weather condition, and operational parameters are evaluated on the basis of thermal efficiency, outlet temperature, Heat loss, and Heat transfer. Results reveal that the average efficiency is approximately 69% at a flow rate of 290 m3/h. In the testing range of the air flow rate, the frictional coefficient varies from 0.05 to 0.18.

  • experimental investigation and performance evaluation of a vacuum tube solar air collector based on Micro Heat Pipe arrays
    Journal of Cleaner Production, 2017
    Co-Authors: Ting Ting Zhu, Y H Diao, Feng-fei Li, Yao-hua Zhao, Zhenhua Quan
    Abstract:

    Abstract An experimental study was conducted to evaluate the thermal performance of a vacuum tube solar air collector that is based on Micro Heat Pipe arrays (MHPA) and features wavelike fins attached to the condenser section of the MHPA. The experimental results were used to analyze the thermal performance of the collector, particularly the temperature distribution in the different localizations of the air collector. The Heat loss analysis provided a useful parameter to evaluate the Heat loss of the collector. Results showed that a decrease in the inlet, will led to an increase in efficiency because of the reduced Heat losses to the environment. The daily thermal efficiency varied between 50% and 70%. In the performance analysis of the MHPA collector, varying flow rates were employed to observe the change in efficiency, outlet temperature, MHPA temperature behavior variation vs. solar radiation, and air flow rate. The utilization of the collector can reduce the amount of emissions of gaseous waste emissions, which has large energy saving potential and environmental benefits. The proposed MHPA-based vacuum tube solar air collector shows good potential in large-scale applications, such as in the room Heating of farmhouses, industrial buildings, and remote outposts, as well as in the agricultural sector.

  • Experimental study on the thermal performance of a new type of thermal energy storage based on flat Micro-Heat Pipe array
    Energy Conversion and Management, 2016
    Co-Authors: Feng-fei Li, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Jing Liu
    Abstract:

    The thermal performance of an air-based phase change storage unit is analyzed and discussed in this study. The thermal energy storage uses flat Micro-Heat Pipe array (FMHPA) as the core Heat transfer component and lauric acid as phase change material (PCM). An experimental system is devised to test the Heat storage–release property of the storage unit under different inlet temperatures and flow rates of the Heat transfer medium. The performance of the storage unit and the melting/solidification curves of the phase change material are obtained based on extensive experimental data. Experimental results indicate that the flat Micro-Heat Pipe array exhibits excellent temperature uniformity in the Heat storage–release process, and the performance of the storage unit is efficient and steady.

Yan-hua Diao - One of the best experts on this subject based on the ideXlab platform.

  • thermal performance of integrated collector storage solar air Heater with evacuated tube and lap joint type flat Micro Heat Pipe arrays
    Applied Energy, 2020
    Co-Authors: Zeyu Wang, Yan-hua Diao, Yao-hua Zhao, Lin Liang, Chuanqi Chen, Tengyue Wang
    Abstract:

    Abstract To alleviate the problem of global warming and the energy crisis, this study proposed an integrated collector storage solar air Heater that uses evacuated tubes as solar absorbers and paraffin as thermal storage material. In the proposed unit, lap joint-type flat Micro-Heat Pipe arrays serve as Heat conductors that transmit the solar energy absorbed by the evacuated tubes to the thermal storage tank or transfer the Heat stored in the tank to the air flow channel. Outdoor experiments were carried out to obtain the thermal performance of the proposed device during charging and discharging. The effects of weather conditions, supply air flow rates, and inlet temperature on the thermal response of the integrated collector storage solar air Heater were reported. The thermal storage efficiency during the experiment period ranged from 56.1% to 67.5% when the mean outdoor temperature ranged from −5.7 °C to 36.2 °C. The mean thermal extraction power and thermal released efficiency reached 1268.8 W and 98.5%, respectively. The results of the energy conversion process analysis and mathematical fitting showed that the mean charging efficiency was linear with the normalized temperature difference. The mean outlet temperature and mean extraction power were linear with the inlet temperature and exponential with the air flow rate. A conceptual design of an air Heating system using the integrated collector storage solar air Heater for a 9.9 m2 building was presented. The benefit pre-evaluation revealed that the system can reduce carbon emissions by approximately 5.8 tons over its life cycle.

  • experimental study on an integrated collector storage solar air Heater based on flat Micro Heat Pipe arrays
    Energy and Buildings, 2017
    Co-Authors: Zeyu Wang, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Lin Liang, F W Bai
    Abstract:

    Abstract This study investigated the performance of an integrated collector storage solar air Heater based on latent Heat storage and flat Micro-Heat Pipe arrays. The structure and working principle of the device were explained in detail. The effective area of the collector is 0.93 m 2 , and the mass of the phase change material (PCM) is 45.8 kg. An integrated collector storage experimental system was set up, and outdoor experiments were conducted to demonstrate the feasibility of the device for energy storage and air Heating. The temperature distribution of the PCM was recorded during charging and discharging to monitor the propagation of the melting and freezing front. Efficiency and power during charging and discharging were also calculated. The integrative device exhibited 59% and 91.6% efficiencies for solar air charging and discharging at 393 and 344 W power, respectively.

  • thermal performance of solar air collection storage system with phase change material based on flat Micro Heat Pipe arrays
    Energy Conversion and Management, 2017
    Co-Authors: Tengyue Wang, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Jing Liu, Xiangqian Wei
    Abstract:

    Abstract In this study, a new type of solar air collection-storage thermal system (ACSTS) with phase change material (PCM) is designed using flat Micro-Heat Pipe arrays (FMHPA) as the Heat transfer core element. The solar air collector comprises FMHPA and vacuum tubes. The latent thermal storage device (LTSD) utilizes lauric acid, which is a type of fatty acid, as PCM. The experiments test the performance of collector efficiency and charging and discharging time of thermal storage device through different air volume flow rates. After a range of tests, high air volume flow rate is concluded to contribute to high collector efficiency and short charging and discharging time and enhance instantaneous Heat transfer, whereas an air volume flow rate of 60 m 3 /h during discharging provides a steady outlet temperature. The cumulative Heat transfer during discharging is between 4210 and 4300 kJ.

  • performance evaluation of a novel flat plate solar air collector with Micro Heat Pipe arrays mhpa
    Applied Thermal Engineering, 2017
    Co-Authors: Ting Ting Zhu, Yan-hua Diao, Yao-hua Zhao
    Abstract:

    Abstract This paper proposes a new type of a flat-plate solar air collector (SAC) with Micro-Heat Pipe arrays (MHPA), which consist of a Heat collection and transfer section and an air ventilation and Heat exchange section. In the unique structure, the Heat exchange of air is separated from Heat collection and transmission. This work experimentally and theoretically investigates the Heat transfer and friction factor characteristics of the proposed MHPA-flat plate solar air collector. Numerical simulation and experimental results are compared to show the instantaneous performance of the collector under quasi-steady state conditions. Efficiency, time constant, inlet temperature, outlet temperature, absorber temperature, and glass cover temperature are obtained. The effects of weather condition, and operational parameters are evaluated on the basis of thermal efficiency, outlet temperature, Heat loss, and Heat transfer. Results reveal that the average efficiency is approximately 69% at a flow rate of 290 m3/h. In the testing range of the air flow rate, the frictional coefficient varies from 0.05 to 0.18.

  • Experimental study on the thermal performance of a new type of thermal energy storage based on flat Micro-Heat Pipe array
    Energy Conversion and Management, 2016
    Co-Authors: Feng-fei Li, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Jing Liu
    Abstract:

    The thermal performance of an air-based phase change storage unit is analyzed and discussed in this study. The thermal energy storage uses flat Micro-Heat Pipe array (FMHPA) as the core Heat transfer component and lauric acid as phase change material (PCM). An experimental system is devised to test the Heat storage–release property of the storage unit under different inlet temperatures and flow rates of the Heat transfer medium. The performance of the storage unit and the melting/solidification curves of the phase change material are obtained based on extensive experimental data. Experimental results indicate that the flat Micro-Heat Pipe array exhibits excellent temperature uniformity in the Heat storage–release process, and the performance of the storage unit is efficient and steady.

Zeyu Wang - One of the best experts on this subject based on the ideXlab platform.

  • numerical and experimental investigations of latent thermal energy storage device based on a flat Micro Heat Pipe array metal foam composite structure
    Renewable Energy, 2020
    Co-Authors: Lin Liang, Y H Diao, Yao-hua Zhao, Zeyu Wang, Fanfei Bai
    Abstract:

    Abstract Latent Heat thermal energy storage (LHTES) is crucial in the application of renewable energy and waste Heat recovery. A novel LHTES device with a flat Micro-Heat Pipe array (FMHPA)–metal foam composite structure is designed in this study to obtain excellent Heat transfer performance. An evaluation standard called integrated power is proposed to assess and compare the structural advantages of the LHTES device with others. Performances of FMHPA, temperature distribution, effort of inlet temperature and velocity of Heat transfer fluid (HTF) are also studied in the experiments. A three-dimensional numerical model is developed to investigate the effort of porosity and pore density of metal foam on the charging process. Results show that the FMHPA–copper foam composite structure improves the performance of the LHTES device. This structure exhibits stronger Heat transfer performance than that of other devices. The increasing inlet temperature of HTF has a better promotion effect on power than raising HTF velocity. High porosity is conducive to natural convection but detrimental to Heat conduction. High pore density is disadvantageous to natural convection and does not affect Heat conduction.

  • thermal performance of integrated collector storage solar air Heater with evacuated tube and lap joint type flat Micro Heat Pipe arrays
    Applied Energy, 2020
    Co-Authors: Zeyu Wang, Yan-hua Diao, Yao-hua Zhao, Lin Liang, Chuanqi Chen, Tengyue Wang
    Abstract:

    Abstract To alleviate the problem of global warming and the energy crisis, this study proposed an integrated collector storage solar air Heater that uses evacuated tubes as solar absorbers and paraffin as thermal storage material. In the proposed unit, lap joint-type flat Micro-Heat Pipe arrays serve as Heat conductors that transmit the solar energy absorbed by the evacuated tubes to the thermal storage tank or transfer the Heat stored in the tank to the air flow channel. Outdoor experiments were carried out to obtain the thermal performance of the proposed device during charging and discharging. The effects of weather conditions, supply air flow rates, and inlet temperature on the thermal response of the integrated collector storage solar air Heater were reported. The thermal storage efficiency during the experiment period ranged from 56.1% to 67.5% when the mean outdoor temperature ranged from −5.7 °C to 36.2 °C. The mean thermal extraction power and thermal released efficiency reached 1268.8 W and 98.5%, respectively. The results of the energy conversion process analysis and mathematical fitting showed that the mean charging efficiency was linear with the normalized temperature difference. The mean outlet temperature and mean extraction power were linear with the inlet temperature and exponential with the air flow rate. A conceptual design of an air Heating system using the integrated collector storage solar air Heater for a 9.9 m2 building was presented. The benefit pre-evaluation revealed that the system can reduce carbon emissions by approximately 5.8 tons over its life cycle.

  • numerical investigation of the thermal performance enhancement of latent Heat thermal energy storage using longitudinal rectangular fins and flat Micro Heat Pipe arrays
    Applied Energy, 2019
    Co-Authors: Y H Diao, Zeyu Wang, Lin Liang, Yue Zhao, Fanfei Bai
    Abstract:

    Abstract The performance of a new type of latent Heat thermal energy storage (LHTS) device based on flat Micro-Heat Pipe arrays (FMHPAs) with longitudinal rectangular fins is numerically studied by enthalpy–porosity technique based on finite volume method (FVM) in this research. The numerical model is verified correct. The temperature distribution and phase transition process in different directions of the interior of a thermal storage tank and the effects of fin height, spacing, and thickness on charging power and thermal storage capacity are also analyzed numerically. Results show that phase interface is presented in U type in the horizontal direction. In the vertical direction, the phase change material (PCM) among fins melts from up to down when the fin spacing is larger than 6 mm, and the opposite occurs when the fin spacing is less than 6 mm. The thermal storage capacity of the LHTS device is reduced drastically when the fin spacing is less than 4.14 mm. For fin height, the structure of multiple rows of FMHPAs with dwarf fins is recommended because it exhibits large power and exerts a small negative effect on thermal storage capacity. Fin thickness has a minimal effect on charging power and thermal storage capacity. The study results provide optimization design guidance for LHTS devices based on FMHPAs under various application backgrounds, such as solving the contradiction between energy supply and demand in solar thermal systems and the peak load shifting of electricity in Heat pump systems.

  • experimental study on an integrated collector storage solar air Heater based on flat Micro Heat Pipe arrays
    Energy and Buildings, 2017
    Co-Authors: Zeyu Wang, Yan-hua Diao, Ting Ting Zhu, Yao-hua Zhao, Lin Liang, F W Bai
    Abstract:

    Abstract This study investigated the performance of an integrated collector storage solar air Heater based on latent Heat storage and flat Micro-Heat Pipe arrays. The structure and working principle of the device were explained in detail. The effective area of the collector is 0.93 m 2 , and the mass of the phase change material (PCM) is 45.8 kg. An integrated collector storage experimental system was set up, and outdoor experiments were conducted to demonstrate the feasibility of the device for energy storage and air Heating. The temperature distribution of the PCM was recorded during charging and discharging to monitor the propagation of the melting and freezing front. Efficiency and power during charging and discharging were also calculated. The integrative device exhibited 59% and 91.6% efficiencies for solar air charging and discharging at 393 and 344 W power, respectively.