The Experts below are selected from a list of 33441 Experts worldwide ranked by ideXlab platform
Ma Guoyuan - One of the best experts on this subject based on the ideXlab platform.
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experimental study on two stage compression refrigeration Heat Pump System with dual cylinder rolling piston compressor
Applied Thermal Engineering, 2014Co-Authors: Xu Shuxue, Ma GuoyuanAbstract:Abstract A thermodynamically analytical model on the two-stage compression refrigeration/Heat Pump System with vapor injection was derived. The optimal volume ratio of the high-pressure cylinder to the low-pressure one has been discussed under both cooling and Heating conditions. Based on the above research, the prototype was developed and its experimental setup established. A comprehensive experiments for the prototype have been conducted, and the results show that, compared with the single-stage compression Heat Pump System, the cooling capacity and cooling COP can increase 5%–15% and 10–12%, respectively. Also, the Heating capacity with the evaporating temperature ranging from 0.3 to 3 °C is 92–95% of that under the rate condition with the evaporating temperature of 7 °C, and 58% when the evaporation temperature is between −28 °C and −24 °C.
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experiment study of an enhanced vapor injection refrigeration Heat Pump System using r32
International Journal of Thermal Sciences, 2013Co-Authors: Xu Shuxue, Ma Guoyuan, Liu Qi, Liu ZhongliangAbstract:Abstract R32, with an ozone depletion potential ( ODP ) of zero and a global warming potential ( GWP ) of 675, may be an acceptable working fluid for refrigeration/Heat Pump Systems to replace HFCs. The performance of an enhanced vapor injection refrigeration/Heat Pump System (EVI System) was experimentally investigated using R32. The results show that this System reduces the discharge temperatures for both cooling and Heating, with the Heating capacity of the EVI System using R32 3 – 9% higher than that of the single-stage System. The cooling capacity, cooling EER and Heating COP depend on the refrigerant intermediate pressure and the operating conditions so they can be bigger or smaller than for the single-stage System. The best range of relative vapor injection mass is 12 – 16% for the best overall cooling and Heating performance. Vapor injection changes the Systems operating conditions, and increases both the evaporating and condensing temperatures by 0.8 – 1 °C.
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exergy analysis for quasi two stage compression Heat Pump System coupled with ejector
Experimental Thermal and Fluid Science, 2011Co-Authors: Xu Shuxue, Ma GuoyuanAbstract:Abstract Ejectors are simple mechanical components, can utilize high pressure energy from liquid in the quasi two-stage compression Heat Pump System coupled with scroll compressor, and the performance of the Heat Pump System can be further improved. According to thermal analysis model based on the first and second law of thermodynamics, the Heat Pump prototype has been developed and comprehensively tested, the influence of ejector on the Heat Pump System was exergetically analyzed using experimental data of the prototype. The results show that, compressor has the greatest exergy loss, amounts to about 77% of the total exergy; ejector can recover the fluid pressure exergy in supplementary circuit compared with the throttling element in the quasi two-stage compression Heat Pump System, decreases the exergy loss of compressor; and the exergetic efficiency can be improved about 3–5%, while the exergy output remains nearly constant.
Xiaosong Zhang - One of the best experts on this subject based on the ideXlab platform.
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study on performance of a novel energy efficient Heat Pump System using liquid desiccant
Applied Energy, 2018Co-Authors: Nannan Shan, Yonggao Yin, Xiaosong ZhangAbstract:Abstract In this paper, a novel Heat Pump System is proposed, which operates as a Heat-source-tower Heat Pump with no frosting in winter, and as a hybrid refrigerant System consisting of a conventional chiller combined with a liquid desiccant dehumidification and evaporative cooling subSystem in summer. A validated mathematical model of the proposed System operating in summer is established to investigate the effects of key parameters, including solution to refrigerant flow ratio (FR), condensation Heat recovery ratio (Rcond) and ambient parameters, on the cooling performance. Besides, this paper analyzes key factors that should be considered in designing the Heat exchange area of the solution-cooled condenser (SCC). The results show that the maximum COP and ECOP of the Heat Pump System are 13.4% and 10.3% higher than those of conventional vapor compression refrigerant Systems under the typical summer condition of Nanjing, respectively. The recommended range of FR is from 1.2 to 6 and that for Rcond is from 16% to 40%. Moreover, the proposed System is more superior to conventional ones when applied in hot and humid regions.
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performance study of parallel type hybrid power gas engine driven Heat Pump System
Energy and Buildings, 2013Co-Authors: Yanwei Wang, Liang Cai, Xiaosong ZhangAbstract:Abstract This paper analyzes the operating principle and the advantages of the parallel-type hybrid-power gas engine-driven Heat Pump System (PHGHP) and builds test Systems to test the performance of the System in the Heating conditions and cooling conditions. PHGHP used Heat Pump System's cooling capacity, Heat capacity, fuel-consumed flow, fuel consumed-rate, thermal efficiency and reclaimed Heat as the economic analysis parameters. In addition, this paper puts forward the concept of the equivalent fuel-consumed flow and the equivalent output power of engine. The test results show, the speed and torque of gas engine which used the baseline control strategy and combined with a gas engine optimization curve control strategy are always in the designated economic. Fuel-consumed flow changes in 280–340 g (kW h)−1. With compressor speed increasing, the drive System thermal efficiency is maintained between 0.23 and 0.28.
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Study on the performance of a solar assisted air source Heat Pump System for building Heating
Energy and Buildings, 2011Co-Authors: Caihua Liang, Xiaosong Zhang, Xia ZhuAbstract:Abstract This paper proposed a new solar assisted air source Heat Pump System with flexible operational modes to improve the performance of the Heating System. A mathematical model was established on the solar assisted air source Heat Pump System for building Heating with a Heating capacity of 10 kW, and an air source Heat Pump unit was developed to validate the model. The effect of the solar collector area on the performance of the System running in Nanjing was studied. The results showed that the COP of the Heat Pump unit was enhanced with the increase of the solar radiation density during the typical sunny day in the Heating season. In addition, the COP also increased in proportion to the solar collector area. Compared with the case when the solar collector area was 0 m 2 , the COP increase of the Heat Pump and the energy-saving rate were 11.22% and 24% respectively when the solar collector area was 40 m 2 . Meanwhile, the solar equivalent generation power efficiency could reach 11.8%.
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soil temperature distribution around a u tube Heat exchanger in a multi function ground source Heat Pump System
Applied Thermal Engineering, 2009Co-Authors: Shuhong Li, Weihua Yang, Xiaosong ZhangAbstract:Abstract The imbalance of Heat extracted from the earth by the underground Heat exchangers in winter and ejected into it in summer is expected to affect the long term performance of conventional ground source Heat Pump (GSHP) in territories with a cold winter and a warm summer such as the middle and downstream areas of the Yangtze River in China. This paper presents a new multi-function ground source Heat Pump (MFGSHP) System which supplies hot water as well as space cooling/Heating to mitigate the soil imbalance of the extracted and ejected Heat by a ground source Heat Pump System. The Heat transfer characteristic is studied and the soil temperature around the underground Heat exchangers are simulated under a typical climatic condition of the Yangtze River. A three-dimensional model was constructed with the commercial computational fluid dynamics software FLUENT based on the inner Heat source theory. Temperature distribution and variation trend of a tube cluster of the underground Heat exchanger are simulated for the long term performance. The results show that the soil temperature around the underground tube keeps increasing due to the surplus Heat ejected into the earth in summer, which deteriorates the System performance and may lead to the eventual System deterioration. The simulation shows that MFGSHP can effectively alleviate the temperature rise by balancing the Heat ejected to/extracted from underground by the conventional ground source Heat Pump System. The new System also improves the energy efficiency.
Xu Shuxue - One of the best experts on this subject based on the ideXlab platform.
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experimental study on two stage compression refrigeration Heat Pump System with dual cylinder rolling piston compressor
Applied Thermal Engineering, 2014Co-Authors: Xu Shuxue, Ma GuoyuanAbstract:Abstract A thermodynamically analytical model on the two-stage compression refrigeration/Heat Pump System with vapor injection was derived. The optimal volume ratio of the high-pressure cylinder to the low-pressure one has been discussed under both cooling and Heating conditions. Based on the above research, the prototype was developed and its experimental setup established. A comprehensive experiments for the prototype have been conducted, and the results show that, compared with the single-stage compression Heat Pump System, the cooling capacity and cooling COP can increase 5%–15% and 10–12%, respectively. Also, the Heating capacity with the evaporating temperature ranging from 0.3 to 3 °C is 92–95% of that under the rate condition with the evaporating temperature of 7 °C, and 58% when the evaporation temperature is between −28 °C and −24 °C.
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experiment study of an enhanced vapor injection refrigeration Heat Pump System using r32
International Journal of Thermal Sciences, 2013Co-Authors: Xu Shuxue, Ma Guoyuan, Liu Qi, Liu ZhongliangAbstract:Abstract R32, with an ozone depletion potential ( ODP ) of zero and a global warming potential ( GWP ) of 675, may be an acceptable working fluid for refrigeration/Heat Pump Systems to replace HFCs. The performance of an enhanced vapor injection refrigeration/Heat Pump System (EVI System) was experimentally investigated using R32. The results show that this System reduces the discharge temperatures for both cooling and Heating, with the Heating capacity of the EVI System using R32 3 – 9% higher than that of the single-stage System. The cooling capacity, cooling EER and Heating COP depend on the refrigerant intermediate pressure and the operating conditions so they can be bigger or smaller than for the single-stage System. The best range of relative vapor injection mass is 12 – 16% for the best overall cooling and Heating performance. Vapor injection changes the Systems operating conditions, and increases both the evaporating and condensing temperatures by 0.8 – 1 °C.
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exergy analysis for quasi two stage compression Heat Pump System coupled with ejector
Experimental Thermal and Fluid Science, 2011Co-Authors: Xu Shuxue, Ma GuoyuanAbstract:Abstract Ejectors are simple mechanical components, can utilize high pressure energy from liquid in the quasi two-stage compression Heat Pump System coupled with scroll compressor, and the performance of the Heat Pump System can be further improved. According to thermal analysis model based on the first and second law of thermodynamics, the Heat Pump prototype has been developed and comprehensively tested, the influence of ejector on the Heat Pump System was exergetically analyzed using experimental data of the prototype. The results show that, compressor has the greatest exergy loss, amounts to about 77% of the total exergy; ejector can recover the fluid pressure exergy in supplementary circuit compared with the throttling element in the quasi two-stage compression Heat Pump System, decreases the exergy loss of compressor; and the exergetic efficiency can be improved about 3–5%, while the exergy output remains nearly constant.
Minsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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a theoretical refrigerant charge prediction equation for air source Heat Pump System based on sensor information
International Journal of Refrigeration-revue Internationale Du Froid, 2019Co-Authors: Sung Bin Hong, Jin Woo Yoo, Minsoo KimAbstract:Abstract The performance of the Heat Pump System varies greatly depending on the refrigerant charge amount. However, the refrigerant in the System slowly leaks during operation. Therefore, in order to guarantee System performance and life span, it is important to predict the charge amount in real time and recharge the shortage. Nevertheless, since the configuration and control of the Heat Pump System becomes more complicated, it is very difficult to predict the refrigerant charge amount. Various previous studies have been carried out to predict refrigerant charge amount, but most of them are empirical methods or theoretical, but require much experimental data for high accuracy. In this paper, a refrigerant charge amount prediction method which requires only a few experimental data for high prediction accuracy is proposed through theoretical analysis of the refrigerant charge. The proposed method was verified by experiments, and the root mean square error was 3.7% in cooling mode and 8.2% in Heating mode.
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comparison of the Heating performance of an inverter driven Heat Pump System using r410a vapor injection into accumulator and compressor
International Journal of Refrigeration-revue Internationale Du Froid, 2012Co-Authors: Chul Woo Roh, Minsoo KimAbstract:In cold regions, a refrigerant injection technique has been used for enhancing Heating capacity and avoiding the excessively high discharge temperature which is detrimental to reliability of a Heat Pump System. The Heat Pump System in this study having an additional refrigerant injection line into the accumulator was tested to compare with the Heating performances of classic vapor-injection cycle. The Heat Pump System was designed to inject vapor refrigerant into the compressor and accumulator, selectively. Although the refrigerant injection into the compressor (classic vapor-injection cycle) was more effective to enhance Heating capacity, the refrigerant injection into the accumulator could decrease discharge temperature and increase both Heating capacity and COP slightly at the condition of high compressor frequency. In terms of mass balance, the injection stream into the accumulator substituted the evaporator's suction stream flowing to the compressor, so the mass flow rate of condenser was not increased as much as the amount of injected refrigerant.
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capacity control of a Heat Pump System applying a fuzzy control method
Applied Thermal Engineering, 2011Co-Authors: Jong Won Choi, Gilbong Lee, Minsoo KimAbstract:Abstract This paper presents the capacity control of a Heat Pump System using the discharge superHeating of the compressor, concerns the design of a fuzzy controller for a Heat Pump at the outlet of a compressor and compares an optimized fuzzy controller with one that is not optimized. The design of a controller is based on a proper System identification model which determines the System modeling from inputs and outputs and completes the state-space System modeling. The type of input signals is pseudo-random binary sequence and the order of System is 7. The fuzzy controller is selected to modulate the discharge superHeating of the compressor, and then, genetic algorithm is used as a searching tool for obtaining the optimized fuzzy rule table. The experiment results show that the optimized fuzzy controller makes undershoot and overshoot alleviated significantly in the discharge superHeating, outlet temperature of secondary fluid and refrigerant mass flow rate.
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Heating performance enhancement of a co2 Heat Pump System recovering stack exhaust thermal energy in fuel cell vehicles
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Sungchul Kim, Minsoo Kim, In Chul Hwang, Tae Won LimAbstract:Abstract A CO2 Heat Pump System using recovered Heat from the stack coolant was provided for use in fuel cell vehicles, where the high temperature Heat source like in internal combustion engine vehicles is not available. The refrigerant loop consists of an electric drive compressor, a cabin Heater, an outdoor evaporator, an internal Heat exchanger, an expansion valve and an accumulator. The performance characteristics of the Heat Pump System were investigated and analyzed by experiments. The results of Heating experiments were discussed for the purpose of the development and efficiency improvement of a CO2 Heat Pump System, when recovering stack exhaust Heat in fuel cell vehicles. A Heater core using stack coolant was placed upstream of a cabin Heater to preHeat incoming air to the cabin Heater. The performance of the Heat Pump System with Heater core was compared with that of the conventional Heating System with Heater core and that of the Heat Pump System without Heater core, and the Heat Pump System with Heater core showed the best performance of the selected Heating Systems. Furthermore, the coolant to air Heat Pump System with Heater core showed a significantly better performance than the air to air Heat Pump System with Heater core.
Xudong Zhao - One of the best experts on this subject based on the ideXlab platform.
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numerical simulation and experimental validation of a micro channel pv t modules based direct expansion solar Heat Pump System
Renewable Energy, 2020Co-Authors: Xudong Zhao, Jinzhi Zhou, Yanping YuanAbstract:Abstract This paper presents a novel solar driven direct-expansion Heat Pump System employing micro-channel PV/T modules as the evaporator. The System can provide both the electrical power and thermal energy used for space Heating for buildings. Experimental work was carried out to investigate the performance of the System under real-life condition and numerical simulation work was carried out for the same condition as the experimentation using a two-dimensional model developed by the authors. This specialist simulation model contains energy balance calculation of individual models of components, i.e., models of the micro-channel PV/T module (evaporator), compressor, Heat storage tank (condenser), electric expansion valve and testing room. The experimental and simulation results showed a good agreement each other, with the maximum error of 7.2% which is the temperature of refrigerant at the outlet of PV/T modules. The experimental average electrical, thermal and overall efficiencies of the PV/T module are 13.1%, 56.6% and 69.7%, respectively. While the simulated results are 13.7%, 55.0% and 68.7%, respectively. The average experimental and simulated COP of the System is 4.7 and 5.0, respectively. With the solar Heat Pump System providing energy for the room of 150 m2 in the real-life testing condition, the temperature of the room can remain at 18.5 °C which was high enough for the space Heating. Comparison among the simulation and testing results indicated that the simulation model was reasonable for predicting the performance of the System and provided feasibility for analyzing the annual energy performance in the future.
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experimental investigation of a solar driven direct expansion Heat Pump System employing the novel pv micro channels evaporator modules
Applied Energy, 2016Co-Authors: Xudong Zhao, Jinzhi Zhou, Jie Ji, Zhenyu Du, Min YuAbstract:This paper aims to investigate a solar driven direct-expansion Heat Pump System employing the novel PV/micro-channels-evaporator modules, in terms of its solar thermal, electrical and overall efficiency, as well as coefficient of performance (COP), at the real-time operational condition. This work was undertaken through a dedicated System design, construction, field-testing and performance analysis. It was found that the novel PV/micro-channel-evaporator modules could achieve an average thermal, electrical and overall efficiency of 56.6%, 15.4% and 69.7% respectively at the specified operational condition, while average COP of the System reached 4.7. The innovative feature of the System lied in the structure of the evaporator that was made of the parallel-laid micro-channels. Such a structure created the reduced interior cross-sectional area and thus increased vapor flow velocity within the channels, while the high vapor velocity generated a higher shear stress exerted upon the liquid-vapor interface, leading to the reduced liquid film thickness, increased refrigerant evaporation rate, and increased electrical and Heat outputs. The research has provided the fundamental data and experience for developing a highly efficient and practically feasible solar Heat Pump System applicable to the cold climatic conditions, thus contributing to significant fossil fuel saving and carbon reduction in the global extent.
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dynamic performance of a novel solar photovoltaic loop Heat pipe Heat Pump System
Applied Energy, 2014Co-Authors: Xingxing Zhang, Xudong Zhao, Jingchun Shen, Jihuan Xu, Xiaotong YuAbstract:Objective of the paper is to present an investigation into the dynamic performance of a novel solar photovoltaic/loop-Heat-pipe (PV/LHP) Heat Pump System for potential use in space Heating or hot water generation. The methods used include theoretical computer simulation, experimental verification, analysis and comparison. The fundamental equations governing the transient processes of solar transmission, Heat transfer, fluid flow and photovoltaic (PV) power generation were appropriately integrated to address the energy balances occurring in different parts of the System, e.g., glazing cover, PV cells, fin sheet, loop Heat pipe, Heat Pump cycle and water tank. A dedicated computer model was developed to resolve the above grouping equations and consequently predict the System’s dynamic performance. An experimental rig was constructed and operated under the real weather conditions for over one week in Shanghai to evaluate the System living performance, which was undertaken by measurement of various operational parameters, e.g., solar radiation, photovoltaic power generation, temperatures and Heat Pump compressor consumption. On the basis of the first- (energetic) and second- (exergetic) thermodynamic laws, an overall evaluation approach was proposed and applied to conduct both quantitative and qualitative analysis of the PV/LHP module’s efficiency, which involved use of the basic thermal performance coefficient (COPth) and the advanced performance coefficient (COPPV/T) of such a System. Moreover, a simple comparison between the PV/LHP Heat-Pump System and conventional solar/air energy Systems was conducted. The research results indicated that under the testing outdoor conditions, the mean daily electrical, thermal and overall energetic and exergetic efficiencies of the PV/LHP module were 9.13%, 39.25%, 48.37% and 15.02% respectively, and the average values of COPth and COPPV/T were 5.51 and 8.71. The PV/LHP module was found to achieve 3–5% higher solar exergetic efficiency than standard PV Systems and about 7% higher overall solar energetic efficiency than the independent solar collector. Compared to the conventional solar/air Heat Pump Systems, the PV/LHP Heat Pump System could achieve a COP figure that is around 1.5–4 times that for the conventional Systems. It is concluded that the computer model is able to achieve a reasonable accuracy in predicting the System’s dynamic performance. The PV/LHP Heat Pump System is able to harvest significant amount of solar Heat and electricity, thus enabling achieving enhanced solar thermal and electrical efficiencies. All these indicate a positive implication that the proposed System has potential to be developed into a high performance PV/T technology that can contribute to significant fossil fuel energy saving and carbon emission.
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design fabrication and experimental study of a solar photovoltaic loop Heat pipe based Heat Pump System
Solar Energy, 2013Co-Authors: Xingxing Zhang, Xudong Zhao, Jingchun Shen, Xuezhi LiuAbstract:In this paper, a novel solar photovoltaic/loop-Heat-pipe (PV/LHP) module-based Heat Pump System was designed and fabricated for both electricity and hot water generation. A coated aluminium-alloy (Al-alloy) sheet was applied as the baseboard of PV cells for enhanced Heat dissipation to the surroundings, which was characterised by a series of laboratory-controlled conditions over the conventional Tedlar–Polyester–Tedlar (TPT) baseboard. The whole prototype System was subsequently evaluated in outdoor weather conditions throughout a consecutive period for about one week. Impact of several external parameters to the PV panel with different baseboards was discussed and the results showed that weaker incident radiation, lower air temperature, higher wind speed, and ground mounting solution, were propitious to the PV electrical performance. Given the specific indoor testing conditions, temperature of the Al-alloy based PV cells was observed at about 62.4 C, which was 5.2 C lower than that of the TPT based PV cells, and its corresponding PV efficiency was about 9.18%, nearly 0.26% higher than the TPT based type. During the outdoor testing, the mean daily electrical, thermal and overall energetic and exergetic efficiencies of the PV/LHP module were measured at 9.13%, 39.25%, 48.37% and 15.02% respectively. The basic-thermal System performance coefficient (COPth) was found at 5.51 and the advanced System performance coefficient (COPPV/T) was nearly 8.71. A simple comparison was also conducted between the PV/LHP based Heat-Pump System and those conventional solar/air energy Systems, which indicated that this advanced System harvests larger amount of solar energy and therefore enables enhanced solar efficiency and System performance. Basic analysis into the economic and environmental benefits of this prototype System further demonstrated such technology will be competitive in the future energy supply industry with a payback period of 16 (9) years and a life-cycle carbon reduction of 12.06 (2.94) tons in Shanghai (London). 2013 Elsevier Ltd. All rights reserved.
