This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger(IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX(EJE-...This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger(IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX(EJE-IHX-S) . The comparison includes the effects of changes in operating conditions such as cooling water flow rate and inlet temperature. Experiments are conducted to assess the influence of the IHX on the heating coefficient of performance(COPr) ,heating capacity,entrainment ratio,pressure lift,and other parameters. The primary flow rate of the EJE-IHX-S is higher than that of the EJE-S. The pressure lift and actual ejector work recovery are reduced when the IHX is added to the transcritical CO2 ejector system. Using a more practical performance calculation,the compression ratio in the EJE-S is reduced by 10.0%-12.1%,while that of EJE-IHX-S is reduced only by 5.6%-6.7% compared to that of a conventional transcritical CO2 system. Experimental results are used to validate the findings that the IHX weakens the contribution of the ejector to the system performance.展开更多
The complementary of biomass and solar energy in combined cooling,heating and power(CCHP)system provides an efficient solution to address the energy crisis and environmental pollutants.This work aims to propose a mult...The complementary of biomass and solar energy in combined cooling,heating and power(CCHP)system provides an efficient solution to address the energy crisis and environmental pollutants.This work aims to propose a multi-objective optimization model based on the life cycle assessment(LCA)method for the optimal design of hybrid solar and biomass system.The life-cycle process of the poly-generation system is divided into six phases to analyze energy consumption and greenhouse gas emissions.The comprehensive performances of the hybrid system are optimized by incorporating the evaluation criteria,including environmental impact in the whole life cycle,renewable energy contribution and economic benefit.The non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ)with the technique for order preference by similarity to ideal solution(TOPSIS)method is employed to search the Pareto frontier result and thereby achieve optimal performance.The developed optimization methodology is used for a case study in an industrial park.The results indicate that the best performance from the optimized hybrid system is reached with the environmental impact load reduction rate(EILRR)of 46.03%,renewable energy contribution proportion(RECP)of 92.73%and annual total cost saving rate(ATCSR)of35.75%,respectively.By comparing pollutant-eq emissions of different stages,the operation phase emits the largest pollutant followed by the phase of raw material acquisition.Overall,this study reveals that the proposed multi-objective optimization model integrated with LCA method delivers an alternative path for the design and optimization of more sustainable CCHP system.展开更多
The design and potential application analysis of the novel solar-absorbing integrated facade module and its corresponding building-integrated solar facade water heating system are presented in this study.Compared with...The design and potential application analysis of the novel solar-absorbing integrated facade module and its corresponding building-integrated solar facade water heating system are presented in this study.Compared with the conventional building envelope,the main novities of the proposed facade module lie in its contributions towards the supplied water preheating to loads and the internal heat gain reduction.Besides,the proposed building-integrated solar facade water heating system broadens the combination modes of the solar thermal system and the building envelope.A dynamic model is introduced first for system design and performance prediction.To evaluate the energy-saving potential and feasibility of the implementation of the proposed facade module,this paper carried out a suitable case study by replacing the conventional facade module in the ongoing retrofitting project of a kitchen,part of the canteen of a graduate school.The detailed thermal performances of three system design options are compared in the typical winter and summer weeks and throughout the year,and then,with the preferred system design,the economic,energy,and environmental effects of the proposed system are evaluated.It was found that the system with a high flow rate of the circulating water is suggested.The annual electricity saved reaches 4175.3 kWh with yearly average thermal efficiency at 46.9%,and its corresponding cost payback time,energy payback time,and greenhouse gas payback time are 3.8,1.7,1.7 years,respectively.This study confirms the feasibility and long-term benefits of the proposed building-integrated solar facade water heating system in buildings.展开更多
The relation of interannual anomaly of East Asian monsoon to the ENSO cycle is investigated in terms of even and odd symmetry analysis over a tropical heating field based on the past 30-year data. Evidence suggests th...The relation of interannual anomaly of East Asian monsoon to the ENSO cycle is investigated in terms of even and odd symmetry analysis over a tropical heating field based on the past 30-year data. Evidence suggests that odd and even symmetry components related to the monsoon and Walker heating, respectively, effectively describe the East Asian monsoon circulation and Pacific Walker analog, with the monsoon intensity index corresponding to its heating vigor and western Pacific Walker heating vigor to ENSO phase change, both types of heating marked by pronounced seasonal variation and phase-locking; the key region for linking monsoon-ENSO interaction is the western Pacific warm pool; the monsoon effect upon ENSO cycle is affected jointly by the seasonal evolution and interannual anomaly of the heating components; the superimposition of an anti-Walker circulation phase produced by interannual winter monsoon perturbation upon a weaker Walker phase on a seasonal basis leads to an El Nino happening in March-April and plays a significant role in maintaining a warm ENSO phase.展开更多
基金Project supported by the National Basic Research Program (973) of China (No.2010CB227304)the National Key Technologies R & D Program in China (No.2006BAJ01A10)
文摘This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger(IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX(EJE-IHX-S) . The comparison includes the effects of changes in operating conditions such as cooling water flow rate and inlet temperature. Experiments are conducted to assess the influence of the IHX on the heating coefficient of performance(COPr) ,heating capacity,entrainment ratio,pressure lift,and other parameters. The primary flow rate of the EJE-IHX-S is higher than that of the EJE-S. The pressure lift and actual ejector work recovery are reduced when the IHX is added to the transcritical CO2 ejector system. Using a more practical performance calculation,the compression ratio in the EJE-S is reduced by 10.0%-12.1%,while that of EJE-IHX-S is reduced only by 5.6%-6.7% compared to that of a conventional transcritical CO2 system. Experimental results are used to validate the findings that the IHX weakens the contribution of the ejector to the system performance.
基金supported by the National Natural Science Foundation of China(Grant No.51976164)。
文摘The complementary of biomass and solar energy in combined cooling,heating and power(CCHP)system provides an efficient solution to address the energy crisis and environmental pollutants.This work aims to propose a multi-objective optimization model based on the life cycle assessment(LCA)method for the optimal design of hybrid solar and biomass system.The life-cycle process of the poly-generation system is divided into six phases to analyze energy consumption and greenhouse gas emissions.The comprehensive performances of the hybrid system are optimized by incorporating the evaluation criteria,including environmental impact in the whole life cycle,renewable energy contribution and economic benefit.The non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ)with the technique for order preference by similarity to ideal solution(TOPSIS)method is employed to search the Pareto frontier result and thereby achieve optimal performance.The developed optimization methodology is used for a case study in an industrial park.The results indicate that the best performance from the optimized hybrid system is reached with the environmental impact load reduction rate(EILRR)of 46.03%,renewable energy contribution proportion(RECP)of 92.73%and annual total cost saving rate(ATCSR)of35.75%,respectively.By comparing pollutant-eq emissions of different stages,the operation phase emits the largest pollutant followed by the phase of raw material acquisition.Overall,this study reveals that the proposed multi-objective optimization model integrated with LCA method delivers an alternative path for the design and optimization of more sustainable CCHP system.
基金the financial supports from Foshan Science and Technology Innovation Project(2018IT100363)Guangdong Basic and Applied Basic Research Foundation(2022A1515110180)Guangdong Technology-transfer Center for the Commercialization of University-Innovations(zc01010000059).
文摘The design and potential application analysis of the novel solar-absorbing integrated facade module and its corresponding building-integrated solar facade water heating system are presented in this study.Compared with the conventional building envelope,the main novities of the proposed facade module lie in its contributions towards the supplied water preheating to loads and the internal heat gain reduction.Besides,the proposed building-integrated solar facade water heating system broadens the combination modes of the solar thermal system and the building envelope.A dynamic model is introduced first for system design and performance prediction.To evaluate the energy-saving potential and feasibility of the implementation of the proposed facade module,this paper carried out a suitable case study by replacing the conventional facade module in the ongoing retrofitting project of a kitchen,part of the canteen of a graduate school.The detailed thermal performances of three system design options are compared in the typical winter and summer weeks and throughout the year,and then,with the preferred system design,the economic,energy,and environmental effects of the proposed system are evaluated.It was found that the system with a high flow rate of the circulating water is suggested.The annual electricity saved reaches 4175.3 kWh with yearly average thermal efficiency at 46.9%,and its corresponding cost payback time,energy payback time,and greenhouse gas payback time are 3.8,1.7,1.7 years,respectively.This study confirms the feasibility and long-term benefits of the proposed building-integrated solar facade water heating system in buildings.
文摘The relation of interannual anomaly of East Asian monsoon to the ENSO cycle is investigated in terms of even and odd symmetry analysis over a tropical heating field based on the past 30-year data. Evidence suggests that odd and even symmetry components related to the monsoon and Walker heating, respectively, effectively describe the East Asian monsoon circulation and Pacific Walker analog, with the monsoon intensity index corresponding to its heating vigor and western Pacific Walker heating vigor to ENSO phase change, both types of heating marked by pronounced seasonal variation and phase-locking; the key region for linking monsoon-ENSO interaction is the western Pacific warm pool; the monsoon effect upon ENSO cycle is affected jointly by the seasonal evolution and interannual anomaly of the heating components; the superimposition of an anti-Walker circulation phase produced by interannual winter monsoon perturbation upon a weaker Walker phase on a seasonal basis leads to an El Nino happening in March-April and plays a significant role in maintaining a warm ENSO phase.
