The Experts below are selected from a list of 24318 Experts worldwide ranked by ideXlab platform
Xiao Song Zhang - One of the best experts on this subject based on the ideXlab platform.
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Experimental study and correlations for heat and mass transfer coefficients in the dehumidifier of a frost-free heat pump system
International Journal of Heat and Mass Transfer, 2019Co-Authors: Bo Sun, Xiao Song ZhangAbstract:Abstract Decreasing the Humidity Ratio of ambient air can effectively prevent the frosting on the evaporator and improve the heat capacity of heat pump in winter. This paper conducts an experimental study and theoretical analysis on the heat and mass transfer performance of the cross-flow dehumidifier in a frost-free heat pump system. A mathematical model for predicting the heat and mass transfer performance in the dehumidifier is developed, and solved by finite difference method. Experimental study is carried out to analyze the influence of key parameters, including inlet air temperature, Humidity Ratio and flow rate, solution temperature, concentRation and flow rate, on the coupled heat and mass transfer performance under low temperature and Humidity Ratio conditions. Based on the mathematical models and experimental results, the correlations of heat and mass transfer coefficients are proposed, and the deviations are within ±20%. Moreover, the effects of the inlet conditions of the liquid desiccant and air on the heat and mass transfer performance are compared with the experimental results reported in literature.
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Analysis of the temperatures of heating and cooling sources and the air states in liquid desiccant dehumidification systems regenerated by return air
Energy, 2019Co-Authors: Xia Song, Lun Zhang, Xiao Song ZhangAbstract:Abstract A typical liquid desiccant (LD) dehumidification system regenerated by return air is driven by a heating source and a cooling source to supply air with the required temperature and Humidity Ratio. This paper analyzes the specific relationship between the heating and cooling sources and the air states by both an analytical method and simulations. The circulating solution is the medium to transfer heat and mass between the air and the heating and cooling sources. The analytical results demonstrate that certain air states (fresh air, supply air, and return air) correspond to one particular solution circulation, which can only be accomplished by a certain pair of temperatures for the heating and cooling sources. With respect to the temperatures of the heating and cooling sources, the supply air state is more influenced by the latter. At a fixed temperature, a lower Humidity Ratio of the supply air demands a significant increase in the temperature of the heating source and a slight decrease in the temperature of the cooling source, resulting in a greater temperature difference between the two sources. At a fixed Humidity Ratio, a lower temperature of the supply air requires lower temperatures for both sources, with a subtle reduction in the temperature difference. For a certain supply air state, the Humidity Ratio of the fresh air is the major factor that determines the temperatures of the two sources; however, a large change in the temperature of the fresh air has little effect on the temperatures of the two sources.
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experimental investigation on heat and mass transfer in heating tower solution regeneRation using packing tower
Energy and Buildings, 2018Co-Authors: Shifang Huang, Xiao Song Zhang, Zhenyu Lv, Caihua LiangAbstract:Abstract Heating towers which can take advantage of energy from air for heating supply is drawing more and more attention. However, the solution dilution problem exists in both open-type and closed-type heating towers, resulting an increasing risk of system freeze. This paper presents an alternative way for heating tower solution regeneRation based on packed beds. A cross-flow regenerator equipped with PVC structured packing was established and glycol aqueous solution was selected as the circulating fluid. The effects of the inlet parameters on moisture removal rate, Humidity effectiveness and thermal efficiency are experimentally investigated. Correlation expressions of heat and mass transfer coefficients are also proposed, which can be primary parameters for simulation and optimization. Besides, performance compaRation between heating tower solution regeneRation and liquid desiccant regeneRation available in the literature is figured out. The results indicate that the impacts of inlet parameters show similar tendency with those in liquid desiccant regeneRation. While the regeneRation temperature required in heating tower is much lower than that in liquid desiccant regeneRation, due to the lower required solution equivalent Humidity Ratio and regenerated air Humidity Ratio. That makes it possible to utilize low-grade energy.
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The Performance Analysis of Single Water Droplet Evaporative Supercooled Process for Ice Slurry Production
Applied Mechanics and Materials, 2013Co-Authors: Jun Hai Yan, Xiao Song ZhangAbstract:To analyze evaporative supercooled process of single water droplet in the air with low temperature and low Humidity Ratio, a mathematical model was constructed to simulate the evaporative process of single water droplet. The droplet temperature during its evapoRation process and the influence of different initial droplet diameter, initial water temperature, air temperature and air Humidity Ratio were analyzed. The evaporative process of droplet in supercooled stage was simulated through the mathematical model, results from modeling basically tallies with the experiment. The numerical results show that lower initial temperature of water droplet can lessen the supercooled time of reaching steady state evapoRation stage. Additionally it can not only lessen the supercooled time but also acquire lower supercooled temperature of water droplet by reducing air Humidity Ratio or lowering air temperature. Furthermore, the smaller initial diameter of water droplet is, the shorter supercooled time of reaching steady state evapoRation stage becomes.
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a new method for determining coupled heat and mass transfer coefficients between air and liquid desiccant
International Journal of Heat and Mass Transfer, 2008Co-Authors: Xiao Song ZhangAbstract:This paper presented the characteristic of liquid desiccant dehumidification based on NTU–Le model. The results showed that the Lewis number Le had little effect on air outlet Humidity Ratio during desiccant solution dehumidification process. A new method called hD–Le separative evaluation method was developed for determining coupled heat and mass transfer coefficients between air and liquid desiccant, through which the heat and mass transfer coefficients between air and liquid desiccant were calculated to obtain from experimental inlet and outlet parameters of air and desiccant solution. The effects of the air volume flow rate, temperature, Humidity Ratio and the solution concentRation, temperature on the Lewis number, heat and mass transfer coefficient were analyzed according to experimental data and the hD–Le separative evaluation method. Based on the computation results, it was concluded that the Lewis number greatly depended on the opeRation parameters and conditions of the air and desiccant. In addition, the correlations of the heat and mass transfer coefficients were developed. The additional 74 groups of experiments validated the developed correlations by comparison of air/solution parameters change with the calculation data.
Pradeep K. Sahoo - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation on solid desiccant–vapor compression hybrid air-conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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experimental investigation on solid desiccant vapor compression hybrid air conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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Performance prediction of rotary solid desiccant dehumidifier in hybrid air-conditioning system using artificial neural network
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Desiccant air conditioning systems are considered as better alternatives to the conventional air conditioning system because of the independent control of temperature and Humidity and being environment friendly. An artificial neural network (ANN) model has been developed to predict the performance of a rotary desiccant dehumidifier for different process air inlet conditions. Dry bulb temperature, Humidity Ratio and flow rate of the process as well as regeneRation air streams of dehumidifier and regeneRation temperatures are used as inputs to the model. The outputs of the model are outlet dry bulb temperature and Humidity Ratio of process as well as regeneRation air streams of dehumidifier, the moisture removal rate and the effectiveness of the dehumidifier. Moisture removal rate and effectiveness of the dehumidifier are considered as the performance indicators of the system. Experiments are also conducted to investigate the performance of the desiccant wheel and the test results are used as target data to train the ANN model. Performance predictions through ANN are compared with the experimental test results and a close agreement is observed.
D B Jani - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation on solid desiccant–vapor compression hybrid air-conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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experimental investigation on solid desiccant vapor compression hybrid air conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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Performance prediction of rotary solid desiccant dehumidifier in hybrid air-conditioning system using artificial neural network
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Desiccant air conditioning systems are considered as better alternatives to the conventional air conditioning system because of the independent control of temperature and Humidity and being environment friendly. An artificial neural network (ANN) model has been developed to predict the performance of a rotary desiccant dehumidifier for different process air inlet conditions. Dry bulb temperature, Humidity Ratio and flow rate of the process as well as regeneRation air streams of dehumidifier and regeneRation temperatures are used as inputs to the model. The outputs of the model are outlet dry bulb temperature and Humidity Ratio of process as well as regeneRation air streams of dehumidifier, the moisture removal rate and the effectiveness of the dehumidifier. Moisture removal rate and effectiveness of the dehumidifier are considered as the performance indicators of the system. Experiments are also conducted to investigate the performance of the desiccant wheel and the test results are used as target data to train the ANN model. Performance predictions through ANN are compared with the experimental test results and a close agreement is observed.
Yasumitsu Tanaka - One of the best experts on this subject based on the ideXlab platform.
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performance of solar desiccant cooling system with silica gel sio2 and titanium dioxide tio2 desiccant wheel applied in east asian climates
Solar Energy, 2012Co-Authors: Napoleon Enteria, Hiroshi Yonekura, Teruaki Mitamura, Hiroshi Yoshino, Akira Satake, Akashi Mochida, Rie Takaki, Ryuichiro Yoshie, Yasumitsu TanakaAbstract:This paper shows the numerical investigation of the developed solar-desiccant cooling system applied in the East Asian climatic conditions with two different desiccant wheel coating materials – the Silica-Gel (SiO2) and the Titanium Dioxide (TiO2). The developed and validated numerical model of the system is currently used in the present study incorporating the two new materials in the desiccant wheel. The system was applied in temperate climate (Beijing and Tokyo), subtropical climate (Taipei and Hong Kong) and tropical climate (Manila and Singapore). The study showed that the specification of the solar-desiccant cooling system varies depending on the climatic conditions. It showed that the required flat plate collector area was getting larger from the temperate climate to the tropical climate. The storage tank requirement was getting bigger in the tropical climate compared to the subtropical and temperate climate. The volumetric flow rate of air was getting higher from temperate climate to tropical climate. In the comparison of the two materials, it was found that the Titanium Dioxide (TiO2) can support lower indoor temperature and Humidity Ratio than the Silica-Gel (SiO2) with the same specification of the solar thermal system and desiccant cooling system. In general, the solar-desiccant cooling system can provide the required indoor temperature and Humidity Ratio. However, for the hot and humid climate such as in tropical, large size of the solar thermal system is needed. In addition, higher volumetric flow of air to support the high cooling load is required. With regard to the new material, Titanium Dioxide, it is proven to be a good alternative material since it can provide lower indoor temperature and Humidity Ratio with higher cooling performance than the Silica-Gel.
Manish Mishra - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigation on solid desiccant–vapor compression hybrid air-conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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experimental investigation on solid desiccant vapor compression hybrid air conditioning system in hot and humid weather
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Solid desiccant–vapor compression hybrid air-conditioning systems are considered as promising alternative to the conventional air conditioning systems because of the independent control of temperature and Humidity and being environment friendly. In the present work, performance study of solid desiccant vapor compression hybrid air-conditioning system has been experimentally carried out for typical hot and humid weather of Roorkee. The overall system performance has also been evaluated for a cooling season from March to mid of October on the basis of various outdoor conditions. It is found that the hybrid cooling system highlights good performance in hot and humid climatic condition. The present system has ensured 61.7% reduction in process air Humidity Ratio at the outlet of desiccant wheel as compared to outdoor Humidity Ratio. The effect of variations in outdoor temperature on dehumidifier performance is also highlighted. The obtained results also show that the system performance is highly sensitive to the change in outside ambient condition.
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Performance prediction of rotary solid desiccant dehumidifier in hybrid air-conditioning system using artificial neural network
Applied Thermal Engineering, 2016Co-Authors: D B Jani, Manish Mishra, Pradeep K. SahooAbstract:Abstract Desiccant air conditioning systems are considered as better alternatives to the conventional air conditioning system because of the independent control of temperature and Humidity and being environment friendly. An artificial neural network (ANN) model has been developed to predict the performance of a rotary desiccant dehumidifier for different process air inlet conditions. Dry bulb temperature, Humidity Ratio and flow rate of the process as well as regeneRation air streams of dehumidifier and regeneRation temperatures are used as inputs to the model. The outputs of the model are outlet dry bulb temperature and Humidity Ratio of process as well as regeneRation air streams of dehumidifier, the moisture removal rate and the effectiveness of the dehumidifier. Moisture removal rate and effectiveness of the dehumidifier are considered as the performance indicators of the system. Experiments are also conducted to investigate the performance of the desiccant wheel and the test results are used as target data to train the ANN model. Performance predictions through ANN are compared with the experimental test results and a close agreement is observed.
