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  • 1.
    Abas, N.
    et al.
    University of Gujrat, Hafiz Hayat Campus, Gujrat, Pakistan.
    Kalair, A. R.
    COMSATS University Islamabad, Islamabad, Pakistan.
    Seyedmahmoudian, M.
    Swinburne University, Australia.
    Naqvi, M.
    Karlstad University.
    Campana, Pietro Elia
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Khan, N.
    COMSATS University Islamabad, Islamabad, Pakistan.
    Dynamic simulation of solar water heating system using supercritical CO2 as mediating fluid under sub-zero temperature conditions2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 161, article id 114152Article in journal (Refereed)
    Abstract [en]

    CO2 is becoming increasingly important as a mediating fluid, and simulation studies are indispensable for corresponding developments. In this study, a simulation-based performance investigation of a solar water heating system using CO2 as a mediating fluid under sub-zero temperature condition is performed using the TRNSYS® software. The maximum performance is achieved at a solar savings fraction of 0.83 during July. The as lowest solar savingss fraction of 0.41 is obtained during December. The annual heat production of the proposed system under Fargo climate is estimated to be about 2545 kWh. An evacuated glass tube solar collector is designed, fabricated and tested for various climate conditions. Moreover, a detailed comparison of the system's performance at sub/supercritical and supercritical pressures shows that the annual heat transfer efficiency of the modeled system is 10% higher at supercritical pressure than at sub/supercritical pressures. This result can be attributd to the strong convection flow of CO2 caused by density inhomogeneities, especially in the near critical region. This condition resuls in high heat transfer rates.

  • 2.
    Blackman, Corey
    et al.
    SaltX Technology, Hägersten, Stockholm, Sweden; Dalarna University, Borlänge, Sweden.
    Gluesenkamp, K. R.
    Oak Ridge National Laboratory, Oak Ridge, TN, United States.
    Malhotra, M.
    Oak Ridge National Laboratory, Oak Ridge, TN, United States.
    Yang, Z.
    Oak Ridge National Laboratory, Oak Ridge, TN, United States; Purdue University, West Lafayette, IN, United States.
    Study of optimal sizing for residential sorption heat pump system2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 150, p. 421-432Article in journal (Refereed)
    Abstract [en]

    Gas-driven sorption heat pumps (GDSHP) show significant potential to reduce primary energy use, associated emissions and energy costs for space heating and domestic hot water production in residential applications. This study considered a bivalent heating system consisting of a sorption heat pump and a condensing boiler, and focuses on the optimal heating capacity of each of these components relative to each other. Two bivalent systems were considered: one based on a solid chemisorption cycle (GDSHPA), and one based on a resorption cycle (GDSHPB). Simulations of year-round space heating loads for two single-family houses, one in New York and the other Minnesota, were carried out and the seasonal gas coefficient of performance (SGCOP) calculated. The sorption heat pump's design heating capacity as a fraction of the bivalent system's total heating capacity was varied from 0 to 100%. Results show that SGCOP was effectively constant for sorption heat pump design capacity greater than 41% of the peak bivalent GDSHPA design capacity in Minnesota, and 32% for GDSHPB. In New York, these values were 42% and 34% for GDSHPA and GDSHPB respectively. The payback period was also evaluated based on postulated sorption heat pump component costs. The fastest payback was achieved with sorption heat pump design capacity between 22 and 44%.

  • 3.
    Fan, Chuan Gang
    et al.
    School of Transportation Engineering, Hefei University of Technology, Hefei, China.
    Li, Ying Zhen
    Fire Research, SP Technical Research Institute of Sweden, Borås, Sweden.
    Ingason, Haukur
    Fire Research, SP Technical Research Institute of Sweden, Borås, Sweden.
    Lönnermark, Anders
    Fire Research, SP Technical Research Institute of Sweden, Borås, Sweden.
    Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate2016In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 93, p. 405-415Article in journal (Refereed)
    Abstract [en]

    Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

  • 4.
    Ji, X.
    et al.
    Royal Institute of Technology, Sweden.
    Yan, Jinyue
    Mälardalen University, School of Sustainable Development of Society and Technology. Royal Institute of Technology, Sweden.
    Thermodynamic properties for humid gases from 298 to 573 K and up to 200 bar2006In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 26, no 2-3, p. 251-258Article in journal (Refereed)
    Abstract [en]

    For the needs of process design, the model proposed in our previous papers was extended to calculate the thermodynamic properties of humidity, heat capacity, molar volume, partial pressure of water vapour, enthalpy and entropy for humid gases (nitrogen, oxygen, air or a nitrogen-oxygen mixture). The comparison with other models from 300 to 473 K and I to 100 bar shows that the results calculated with different models are consistent within 50 bar and 400 K; out of this range, there is some difference. Meanwhile, mole ratios of nitrogen to oxygen in the saturated humid air were calculated from 323 to 523 K and 50 to 250 bar. It is found that the mole ratio of nitrogen to oxygen keeps almost constant, and the effect of the slight changes in the ratio of nitrogen to oxygen on the humidity, enthalpy and entropy of humid air is small enough to be neglected. Moreover, the enthalpy of dry air was predicted, and the comparison with other models again proved the reasonable assumptions and prediction capability of the new model. (c) 2005 Elsevier Ltd. All rights reserved.

  • 5.
    Liu, Shengchun
    et al.
    Tianjin University of Commerce.
    Li, Zheng
    Tianjin University of Commerce.
    Dai, Baomin
    Tianjin University of Commerce.
    Zhong, Zhifeng
    Tianjin University of Commerce.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Song, Mengjie
    Sun, Zhili
    Energetic, economic and environmental analysis of air source transcritical CO2 heat pump system for residential heating in China2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 148, p. 1425-1439Article in journal (Refereed)
    Abstract [en]

    Using air source heat pump system for residential heating is a practical way to replace coal-fired boiler in China to alleviate the haze problem, and CO2 is a promising candidate to replace hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFCs) charged into the system. A mathematical model is developed to comprehensively evaluate the energetic, economical and environmental performances of CO2 heat pump system compared with other three traditional heating methods. The results indicate that the primary energy ratio of CO2 heat pump is the highest and it is a rational way to utilize renewable energy with the renewable energy contribution ratio of 0.60–0.69. The initial capital cost of CO2 heat pump is much higher due to the dominant compressor cost. The emission of CO2 heat pump is lower than that of coal-fired boiler at seasonal performance factor above 2.44. The initial and operation cost can be gradually reduced with the mass production and energy efficiency improvement of CO2 heat pump. It is believe that air source CO2 heat pump system can be employed for home heating in China, especial for the hot summer and cold winter region.

  • 6.
    Shengchun, L.
    et al.
    Tianjin Key Laboratory of Refrigeration Technology, School of Mechanical Engineering, Tianjin University of Commerce, Tianjin, China.
    Xueqiang, L.
    School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
    Mengjie, S.
    Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin Key Laboratory of Refrigeration Technology, School of Mechanical Engineering, Tianjin University of Commerce, Tianjin, China.
    Zhili, S.
    ianjin Key Laboratory of Refrigeration Technology, School of Mechanical Engineering, Tianjin University of Commerce, Tianjin, China.
    Experimental investigation on drying performance of an existed enclosed fixed frequency air source heat pump drying system2018In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 130, p. 735-744Article in journal (Refereed)
    Abstract [en]

    As the quick development of industry drying technology, different heat pump drying systems were proposed in recent decades. Enclosed heat pump drying system was considered as the most widely used system. For an existed enclosed fixed frequency heat pump drying system, drying time could be decreased by increasing air temperature at inlet of drying chamber. However, as a fundamental problem, system drying performance influenced by air flow ratio was not tested and reported in open literatures. Therefore, basing on adding an air bypass duct, drying performance of an enclosed system was experimental investigated in this study, with 15 mm thickness fresh carrot chips used. Furthermore, qualitatively and quantitatively comparisons and discussions on experimental results were conducted. A whole drying process were firstly divided into three stages by different water content ratios, preheating stage at 98–100%, fast drying stage at 20–98%, and later drying stage at 0–20%, respectively. For the inlet air temperature of drying chamber is fixed at 40 °C, material drying time for water content ratio reaching 20% could be effectively decreased as much as 42 min, or 15.0%, by the strategy of hot air bypassed. After the drying time shortened, the calculated energy consumption for compressor was also decreased from 4.27 kWh for AFR at 1.0 to 3.63 kWh for AFR at 0.6. Contributions of this study can guide low temperature material drying process. Clearly, system control optimization and energy saving were both expected.

  • 7.
    Takami, Kourosh Mousavi
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Danielsson, Orjan
    Kanthal AB, SE-73427 Hallstahammar, Sweden.
    Mahmoudi, Jafar
    Mälardalen University, School of Sustainable Development of Society and Technology.
    High power reflector simulation to optimise electrical energy consumption and temperature profile2011In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 31, no 4, p. 477-486Article in journal (Refereed)
    Abstract [en]

    The high power reflector is a new heating solution for use in high power heating systems. It consists of a vacuum formed ceramic fibre hood with an integrated Kanthal (R) Super ceramic heating element. This paper describes simulations that have been performed to optimise characteristics of the high power reflector with respect to output heat power and temperature distribution. The main motivation for this task is to use this system in the annealing furnaces of Surahammar Bruks AB. Simulations of heat transfer were performed with different reflector configurations in the COMSOL (R) software environment. We examined six different types of proposed reflector using a two dimensional model approach. The temperature variations with distance above the reflectors and the temperature profiles in surfaces 20 cm above the elements were simulated. Optimum shapes and dimensions were found that produced the highest peak temperature, mean temperature, and uniform temperature distribution in the surface above the element. 3D simulations were performed to verify the accuracy of the 20 simulations. The maximum difference between the 2D and 3D results was about 5%. The results showed a satisfactory fit with average furnace temperatures. (C) 2010 Elsevier Ltd. All rights reserved.

  • 8.
    Tan, Y.
    et al.
    School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Nookuea, Worrada
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Evaluation of viscosity and thermal conductivity models for CO2 mixtures applied in CO2 cryogenic process in carbon capture and storage (CCS)2017In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 123, p. 721-733Article in journal (Refereed)
    Abstract [en]

    The cryogenic process is used for CO2 purification in oxy-fuel combustion power plant, and multi-stream heat exchanger is one of the most important components. Viscosity and thermal conductivity are key transport properties in the design of plate-fin multi-stream heat exchanger. It is necessary to evaluate the impacts of viscosity and thermal conductivity models on the design of the heat exchanger. In this paper, different viscosity models and thermal conductivity models for CO2 mixtures with non-condensable impurities were first evaluated separately by comparing the calculated results with experimental data. Results show that for viscosity, the absolute average deviation of KRW model is the smallest, which is 1.3%. For thermal conductivity, model developed by Ely and Hanley, with absolute average deviation of 3.5%, is recommended. The impact of property models on the design of plate-fin multi-stream heat exchanger was also analyzed. The thermal conductivity model has a noticeable impact on the plate-fin multi-stream heat exchanger design, and the deviation in design size of heat exchanger by using different thermal conductivity models may reach up to 7.5%. The future work on how to improve the property models was discussed. © 2017 Elsevier Ltd

  • 9. Tan, Y.
    et al.
    Nookuea, Worrada
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, China.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Impacts of thermos-physical properties on plate-fin multi-stream heat exchanger design in cryogenic process for CO2 capture2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 149, p. 1445-1453Article in journal (Refereed)
    Abstract [en]

    Oxy-fuel combustion is one of the most promising technologies for CO2 capture for power plants. In oxy-fuel combustion plants, cryogenic process can be applied for CO2 purification because the main impurities in flue gas are non-condensable gases. The multi-stream plate-fin heat exchanger is one of the most important components in the CO2 cryogenic system. In-depth understanding of the impacts of property on the heat exchanger is of importance for appropriate design. In order to investigate the impacts of properties on sizing the heat exchanger and to further identify the key properties to be prioritized for the property model development, this paper presented the design procedure for the plate-fin multi-stream heat exchanger for the CO2 cryogenic process. Sensitivity study was conducted to analyze the impacts of thermos-physical properties including density, viscosity, heat capacity and thermal conductivity. The results show that thermal conductivity has the most significant impact and hence, developing a more accurate thermal conductivity model is more important for the heat exchanger design. In addition, even though viscosity has less significant impact compared to other properties, the larger deviation range of current viscosity models may lead to higher uncertainties in volume design and annual capital cost of heat exchanger. 

  • 10.
    Wang, Y.
    et al.
    Tianjin University of Commerce, Tianjin, China.
    Wang, B.
    Tianjin University of Commerce, Tianjin, China.
    Zhu, K.
    Tianjin University of Commerce, Tianjin, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin University of Commerce, Tianjin, China.
    He, W.
    Tianjin University of Commerce, Tianjin, China.
    Liu, S.
    Tianjin University of Commerce, Tianjin, China.
    Energy saving potential of using heat pipes for CPU cooling2018In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 143, p. 630-638Article in journal (Refereed)
    Abstract [en]

    Air cooling is the most common cooling solution for central processing units (CPUs). However, the heat dissipation capacity of conventional air-cooled heatsinks is limited because of non-uniform temperature distribution in the base of heatsinks. Embedded heat pipes into the heatsink is an effective method to improve the heat dissipation of the CPU and make the temperature distribution of the heatsink base more uniform. This work studied the cooling performance of the heat pipe embedded heatsinks, including the surface temperature, the average temperature of base, the thermal resistance and the power consumption. The impact of the different arrangements of heat pipes on the temperature distribution was also investigated. Results show that to obtain the same CPU temperature, a lower air velocity was needed for the heatsink with embedded heat pipe at the same heat flux. The minimum thermal resistance of the studied heat pipe embedded heatsinks was 0.15 °C/W, which is lower than that of the reference conventional heatsink, 0.22 °C/W. In addition, the heatsink with H-shape arrangement of embedded heat pipes had the best overall performance, which cooling capacity was increased by 22.5% and the weight of the heatsink was reduced by 30.1% compared with the heatsink without heat pipes. The energy saving potential was also evaluated based on the measured real operating status of CPUs. The dynamic simulation results show that the total fan power consumption can be effectively reduced when using a heat pipe embedded heatsink to replace the conventional heatsink, which can be up to 66.2%. 

  • 11. Widarsson, Björn
    et al.
    Dotzauer, Erik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Bayesian network-based early-warning for leakage in recovery boilers2008In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 28, no 7, p. 754-760Article in journal (Refereed)
    Abstract [en]

    Early-warning for leakage in a recovery boiler can help the process operator to detect faults and take action when a dangerous situation is developing. By analysing the mass-balances on both the steam and combustion side of the boiler in a Bayesian network, the probability of leakage can be determined and used as an early-warning. The method is tested with real plant data combined with leakage simulations. The results show that it is possible to detect considerably smaller leakages using this method than using the type of simple steam-side mass-balance method that is in use today. Bayesian network is an efficient tool to combine information from measurement signals and calculations giving an early-warning system that is robust to signal faults

  • 12.
    Yang, X.
    et al.
    Xi'an Jiaotong University, Xi'an, China.
    Niu, Z.
    Xi'an Jiaotong University, Xi'an, China.
    Bai, Q.
    Xi'an Jiaotong University, Xi'an, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Cui, X.
    Xi'an Jiaotong University, Xi'an, China.
    He, Y. -L
    Xi'an Jiaotong University, Xi'an, China.
    Experimental study on the solidification process of fluid saturated in fin-foam composites for cold storage2019In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 161, article id 114163Article in journal (Refereed)
    Abstract [en]

    Cold storage can effectively turn electricity to cold energy during off peak hours and reduce electricity peak load by supplying cold energy for air conditioning. Solid-liquid phase change rate is seriously encumbered by the relatively-low thermal conductivity of phase change materials (PCMs). A novel fin-foam structure was established to enhance solidification heat transfer and the solidification characteristics were experimentally explored. An experimental system visualizing solid-liquid interface and temperature monitoring was built. The parameters of fin-foam structure, including fin sizes, fin pitch and number were investigated experimentally. Particular attention was paid to justifying the local thermal equilibrium state via measuring temperature on metallic ligament surface and the saturating fluid in pore space. Results showed that inserting fins into metal foam can make a promotional improvement on solidification rate of water by 28.35%. The solid-liquid interface became locally curved after inserting fins. Thermal adhesive and insulation adhesive did not affect the accuracy at pore-scale temperature measurement. Solidification process can be further enhanced through increasing fin width and number rather than fin pitch. © 2019 Elsevier Ltd

  • 13.
    Zhao, R.
    et al.
    Ministry of Education of China, Tianjin, China.
    Deng, S.
    Ministry of Education of China, Tianjin, China.
    Wang, S.
    Tianjin University, Tianjin, China.
    Zhao, L.
    Ministry of Education of China, Tianjin, China.
    Zhang, Y.
    Ministry of Education of China, Tianjin, China.
    Liu, B.
    Ministry of Education of China, Tianjin, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yu, Z.
    University of Stavanger, Stavanger, Norway.
    Thermodynamic research of adsorbent materials on energy efficiency of vacuum-pressure swing adsorption cycle for CO2 capture2018In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 128, p. 818-829Article in journal (Refereed)
    Abstract [en]

    This paper presents a comprehensive thermodynamic research on energy efficiency of vacuum-pressure swing adsorption (VPSA). The study examined the influence from four types of typical adsorbent materials on the energy efficiency of VPSA by cycle parameters. The selected adsorbent materials are activated carbons, zeolite 5A, zeolite 13X, silica gels, and metal-organic frameworks (MOFs). The study also analyzes the effects of separation temperature, adsorption pressure, desorption pressure, CO2 concentration and percent of unused bed on the energy-efficiency of VPSA cycle. The examined performance parameters are CO2 working capacity, proportionality factor, energy consumption and second-law efficiency. The results show that the energy consumption is approximately 2.0–4.5 MJ/kg and the second-law efficiencies are 4–7% for VPSA cycles using the five adsorbent materials. The effect of adsorbent materials on the energy efficiency mainly depends on the proportionality factor of CO2 working capacity (β) of VPSA cycle, which is important to screen materials at the fixed cyclic boundary conditions and preliminary calculation of second-law efficiency for VPSA cycles. For existing adsorbent materials which are Type I commonly, the lower values of β would lead to the higher second-law efficiencies. The development of new adsorbents of Type III would be extremely urgent in near future. 

  • 14.
    Zhu, K.
    et al.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Li, Xueqiang
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Chen, X.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Wang, Y.
    Key Laboratory of Refrigeration Technology of Tianjin, Tianjin University of Commerce, Tianjin, China.
    Experimental and theoretical study of a novel loop heat pipe2018In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 130, p. 354-362Article in journal (Refereed)
    Abstract [en]

    In order to reduce the heat leakage from the evaporator and achieve a longer transport distance, a new type of loop heat pipe (LHP) has been proposed based on a hypothesis that the circulation of working fluids is driven by not only the capillary head, but also the pressure head due to evaporation. In the evaporator, the wick is separated from the heating surface by a chamber, which can effectively use the pressure head generated by evaporation. In this work, a prototype of such a LHP was studied experimentally and theoretically. In order to understand the mechanism of operation, a new mathematical model was established. Comparing the simulated results with the experimental data about the operation temperature, a good agreement was observed that the average absolute deviation and the maximum absolute deviation were in ranges of 0.67–1.21 °C and −1.3 to 6 °C, respectively. With the validated model, the two driving forces were investigated. Results showed that the ratio of the pressure head of evaporation to the capillary head was in a range of 59–54% corresponding to heating powers from 30 W to 110 W. It confirms that the pressure head due to evaporation plays an important role in the circulation of working fluids.

  • 15.
    Zhu, Kai
    et al.
    Tianjin University of Commerce, Tianjin, China .
    Chen, Xiaoqing
    Tianjin University of Commerce, Tianjin, China .
    Dai, Baomin
    Tianjin University of Commerce, Tianjin, China .
    Zheng, Mingzhu
    Tianjin University of Commerce, Tianjin, China .
    Wang, Yabo
    Tianjin University of Commerce, Tianjin, China .
    Li, Hailong
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Tianjin University of Commerce, Tianjin, China .
    Operation characteristics of a new-type loop heat pipe (LHP) with wick separated from heating surface in the evaporator2017In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 123, p. 1034-1041Article in journal (Refereed)
    Abstract [en]

    The loop heat pipe (LHP) has been widely used for cooling devices with high heat flux. In addition to the capillary pumping force, the pressure head due to evaporation has been assumed to play an important role in the circulation of working fluid. Based on such a hypothesis, a new LHP is designed, in which the wick is separated from the heating surface in the evaporator. Experiments show that such a LHP can start up successfully and reach steady operation, which indirectly verified the hypothesis. The influences of heating power, height of steam chamber, pore radius and porosity of wick are comprehensively investigated. The results show that the start-up time of the new-designed LHP is shorter and the temperature fluctuation is smaller at higher heating power. The steam chamber height has clear impacts on the start-up time and the thermal resistance. The start-up time with the steam chamber height of 2 mm is shorter than that of 3 mm, but the thermal resistance is relatively higher. Moreover, a larger pore radius and a higher porosity of the wick can lead to a shorter start-up time and a smaller thermal resistance of the new LHP.

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