Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a ...Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a multi-time scale optimal scheduling strategy based on model predictive control(MPC)is proposed under the consideration of load optimization.First,load optimization is achieved by controlling the charging time of electric vehicles as well as adjusting the air conditioning operation temperature,and the photovoltaic energy storage building system model is constructed to propose a day-ahead scheduling strategy with the lowest daily operation cost.Second,considering inter-day to intra-day source-load prediction error,an intraday rolling optimal scheduling strategy based on MPC is proposed that dynamically corrects the day-ahead dispatch results to stabilize system power fluctuations and promote photovoltaic consumption.Finally,taking an office building on a summer work day as an example,the effectiveness of the proposed scheduling strategy is verified.The results of the example show that the strategy reduces the total operating cost of the photovoltaic energy storage building system by 17.11%,improves the carbon emission reduction by 7.99%,and the photovoltaic consumption rate reaches 98.57%,improving the system’s low-carbon and economic performance.展开更多
Cement-based materials are the foundation of modern buildings but suffer from intensive energy consumption.Utilizing cement-based materials for efficient energy storage is one of the most promising strategies for real...Cement-based materials are the foundation of modern buildings but suffer from intensive energy consumption.Utilizing cement-based materials for efficient energy storage is one of the most promising strategies for realizing zero-energy buildings.However,cement-based materials encounter challenges in achieving excellent electrochemical performance without compromising mechanical properties.Here,we introduce a biomimetic cement-based solid-state electrolyte(labeled as l-CPSSE)with artificially organized layered microstructures by proposing an in situ ice-templating strategy upon the cement hydration,in which the layered micropores are further filled with fast-ion-conducting hydrogels and serve as ion diffusion highways.With these merits,the obtained l-CPSSE not only presents marked specific bending and compressive strength(2.2 and 1.2 times that of traditional cement,respectively)but also exhibits excellent ionic conductivity(27.8 mS·cm^(-1)),overwhelming most previously reported cement-based and hydrogel-based electrolytes.As a proof-of-concept demonstration,we assemble the l-CPSSE electrolytes with cement-based electrodes to achieve all-cement-based solid-state energy storage devices,delivering an outstanding full-cell specific capacity of 72.2 mF·cm^(-2).More importantly,a 5×5 cm^(2) sized building model is successfully fabricated and operated by connecting 4 l-CPSSE-based full cells in series,showcasing its great potential in self-energy-storage buildings.This work provides a general methodology for preparing revolutionary cement-based electrolytes and may pave the way for achieving zero-carbon buildings.展开更多
In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface...In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface modifier, and organic EV（OEV） with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic（CA-SA）/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC）, thermal gravimetry（TG）, and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density（112.52 J/g）, suitable melting temperature（20.49 ℃）, good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.展开更多
Salt-cavern underground gas storage is technically faced with non-uniform distribution of stratified salt rocks,complex solution mining mechanism,difficult control of solution mining process,less operation safety and ...Salt-cavern underground gas storage is technically faced with non-uniform distribution of stratified salt rocks,complex solution mining mechanism,difficult control of solution mining process,less operation safety and stability of caverns and difficult reconstruction and utilization of old caverns.In view of these technical difficulties,the design concept was fully updated based on the design experience and field practice of Jintan gas storage in Jiangsu,for purpose of maximizing salt layer utilization ratio,improving solution mining efficiency,shortening construction time and ensuring cavity safety.Based on the updated design concept,five series of key technologies were proposed in site evaluation,cavern design and control,stability assessment and storage capacity parameter design,old cavern screening and utilization,and gas storage operation and monitoring.The following results were obtained from the actual application of these key technologies to the Jintan gas storage.First,the actual drilling coincidence rate of geological program is high.Second,the cavern is morphologically coincident with the design.Third,the cavern deformation retract rate is in line with the stability evaluation result.Fourth,old caverns are successfully reconstructed and utilized.Fifth,the arrangement of the monitoring network ensures the operation safety of salt-cavern underground gas storage and makes an important contribution to the peak shaving and supply guarantee of natural gas in the Yangtze River Delta region.In conclusion,the research results provide guidance for the design and engineering implementation of salt-cavern underground gas storage construction program,as well as a theoretical and technical support for the construction of similar gas storages.展开更多
The Photovoltaic Energy storage Direct current and Flexibility(PEDF)system has attracted significant attention in recent years.In this system,charging piles,air conditioning,building energy storage,and photovoltaic ar...The Photovoltaic Energy storage Direct current and Flexibility(PEDF)system has attracted significant attention in recent years.In this system,charging piles,air conditioning,building energy storage,and photovoltaic are connected to the direct current bus,with flexible adjustment capabilities.The increasing presence of flexible loads complicates the calculation of electrical balance in buildings.Building energy storage is a crucial component of the PEDF system,and its storage capacity(kWh)and power(kW)are parameters that need to be determined during the design phase.This study focuses on the energy storage system of PEDF,considering both electricity and cooling storage methods,with the goal of optimizing capacity and power for economy.A dual-layer optimization model of“operational-design optimization”is proposed.The operational optimization model enables the calculation of power supply and demand balance involving multiple flexible loads over the entire year of 8760 hours.In the design optimization model,equipment investment is considered based on the operational optimization model,and particle swarm optimization(PSO)is employed to achieve the design optimization of energy storage system.This study uses a Shenzhen office building as a case study,demonstrating that the installation of battery and cooling storage facility can enhance system economic efficiency,while the scale of photovoltaic installation and time-of-use tariff significantly impact the design of building energy storage solutions.展开更多
With an increasing integration of intermittent distributed energy resources(DERs),the consequent voltage excursion and thermal overloading issues limit the self-sufficiency of distribution networks(DNs).The concept of...With an increasing integration of intermittent distributed energy resources(DERs),the consequent voltage excursion and thermal overloading issues limit the self-sufficiency of distribution networks(DNs).The concept of soft open point(SOP)has been proposed as a promising solution to improve the hosting capacity of DNs.In this paper,considering the ability of building thermal storage(BTS)to increase the penetration of renewable energy in DNs,we provide an optimal planning framework for SOP and DER.The optimal planning model is aimed at minimizing the investment and operational costs while respecting various constraints,including the self-sufficiency requirement of the DN,SOP,building thermal storage capacity and DER operations,etc.A steady-state SOP model is formulated and linearized to be incorporated into the planning framework.To make full use of the BTS flexibility provided by ubiquitous buildings,a differential equation model for building thermal dynamics is formulated.A hybrid stochastic/robust optimization approach is adopted to depict the uncertainties in renewable energy and market prices.IEEE 33-bus feeder and a realistic DN in the metropolitan area of Caracas are tested to validate the effectiveness of the proposed framework and method.Case studies show that SOP/BTS plays a complementary and coordinated coupling role in the thermo-electric system,thereby effectively improving the hosting capacity and self-sufficiency of DNs.展开更多
The presence or absence of occupants in a building has a direct effect on its energy use,as it influences the operation of various building energy systems.Buildings with high occupancy variability,such as universities...The presence or absence of occupants in a building has a direct effect on its energy use,as it influences the operation of various building energy systems.Buildings with high occupancy variability,such as universities,where fluctuations occur throughout the day and across the year,can pose challenges in developing control strategies that aim to balance comfort and energy efficiency.This situation becomes even more complex when such buildings are integrated with renewable energy technologies,due to the inherently intermittent nature of these energy source.To promote widespread integration of renewable energy sources in such buildings,the adoption of advanced control strategies such as model predictive control(MPC)is imperative.However,the variable nature of occupancy patterns must be considered in its design.In response to this,the present study evaluates a price responsive MPC strategy for a solar thermal heating system integrated with thermal energy storage(TES)for buildings with high occupancy variability.The coupled system supplies the building heating through a low temperature underfloor heating system.A case study University building in Nottingham,UK was employed for evaluating the feasibility of the proposed heating system controlled by MPC strategy.The MPC controller aims to optimize the solar heating system’s operation by dynamically adjusting to forecasted weather,occupancy,and solar availability,balancing indoor comfort with energy efficiency.By effectively integrating with thermal energy storage,it maximizes solar energy utilization,reducing reliance on non-renewable sources and ultimately lowering energy costs.The developed model has undergone verification and validation process,utilizing both numerical simulations and experimental data.The result shows that the solar hot water system provided 63%heating energy in total for the case study classroom and saved more than half of the electricity cost compared with that of the original building heating system.The electricity cost saving has been confirmed resulting from the energy shifting from high price periods to medium to low price periods through both active and passive heating energy storages.展开更多
文摘Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a multi-time scale optimal scheduling strategy based on model predictive control(MPC)is proposed under the consideration of load optimization.First,load optimization is achieved by controlling the charging time of electric vehicles as well as adjusting the air conditioning operation temperature,and the photovoltaic energy storage building system model is constructed to propose a day-ahead scheduling strategy with the lowest daily operation cost.Second,considering inter-day to intra-day source-load prediction error,an intraday rolling optimal scheduling strategy based on MPC is proposed that dynamically corrects the day-ahead dispatch results to stabilize system power fluctuations and promote photovoltaic consumption.Finally,taking an office building on a summer work day as an example,the effectiveness of the proposed scheduling strategy is verified.The results of the example show that the strategy reduces the total operating cost of the photovoltaic energy storage building system by 17.11%,improves the carbon emission reduction by 7.99%,and the photovoltaic consumption rate reaches 98.57%,improving the system’s low-carbon and economic performance.
基金support from the National Natural Science Foundation of China(Grant Nos.:52250010 and 52050128)the Natural Science Foundation of Jiangsu Province(Grant No.:BK20230086)+3 种基金L.P.acknowledges support from the National Natural Science Foundation of China(Grant No.:52201242)the Young Elite Scientists Sponsorship Program by CAST(No.2021QNRC001)the Fund of Key Laboratory of Advanced Materials of Ministry of Education(No.AdvMat-2023-12)Z.M.S.acknowledges support from the National Natural Science Foundation of China(Grant No.:U23A20574).
文摘Cement-based materials are the foundation of modern buildings but suffer from intensive energy consumption.Utilizing cement-based materials for efficient energy storage is one of the most promising strategies for realizing zero-energy buildings.However,cement-based materials encounter challenges in achieving excellent electrochemical performance without compromising mechanical properties.Here,we introduce a biomimetic cement-based solid-state electrolyte(labeled as l-CPSSE)with artificially organized layered microstructures by proposing an in situ ice-templating strategy upon the cement hydration,in which the layered micropores are further filled with fast-ion-conducting hydrogels and serve as ion diffusion highways.With these merits,the obtained l-CPSSE not only presents marked specific bending and compressive strength(2.2 and 1.2 times that of traditional cement,respectively)but also exhibits excellent ionic conductivity(27.8 mS·cm^(-1)),overwhelming most previously reported cement-based and hydrogel-based electrolytes.As a proof-of-concept demonstration,we assemble the l-CPSSE electrolytes with cement-based electrodes to achieve all-cement-based solid-state energy storage devices,delivering an outstanding full-cell specific capacity of 72.2 mF·cm^(-2).More importantly,a 5×5 cm^(2) sized building model is successfully fabricated and operated by connecting 4 l-CPSSE-based full cells in series,showcasing its great potential in self-energy-storage buildings.This work provides a general methodology for preparing revolutionary cement-based electrolytes and may pave the way for achieving zero-carbon buildings.
基金Funded by the Major State Research Development Program of China during the 13th Five-Year Plan Period(No.2016YFC0700904)the Science and Technology Support Program of Hubei Province(Nos.2014BAA134 and 2015BAA107)
文摘In order to improve the thermal storage capacity of expanded vermiculite（EV） based formstable composite PCM（FS-PCM） via organic modification of EV, first, EV was modified with a sodium stearate（Na St） as surface modifier, and organic EV（OEV） with hydrophobicity and higher adsorption capacity for fatty acid was obtained. A novel capric-stearic acid eutectic（CA-SA）/OEV FS-PCM with high thermal storage capacity was then developed. OEV and CA-SA/OEV were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, differential scanning calorimetry（DSC）, thermal gravimetry（TG）, and thermal cycling test. Results showed that OEV has obvious hydrophobicity and a higher adsorption capacity for fatty acid. Its adsorption ratio has increased by 48.71% compared with that of EV. CA-SA/OEV possesses high thermal storage density（112.52 J/g）, suitable melting temperature（20.49 ℃）, good chemical compatibility, excellent thermal stability and reliability, indicating great application potential for building energy efficiency. Moreover, organic modification of inorganic matrix may offer novel options for improving its adsorption capacity for organic PCMs and increasing heat storage capacity of corresponding FS-PCMs.
基金supported by the CNPC Major Science and Technology Project“Research and Application of Key Technologies in Geology and Gas Reservoir Engineering of Underground Gas Storage”(No.:2015E-400201).
文摘Salt-cavern underground gas storage is technically faced with non-uniform distribution of stratified salt rocks,complex solution mining mechanism,difficult control of solution mining process,less operation safety and stability of caverns and difficult reconstruction and utilization of old caverns.In view of these technical difficulties,the design concept was fully updated based on the design experience and field practice of Jintan gas storage in Jiangsu,for purpose of maximizing salt layer utilization ratio,improving solution mining efficiency,shortening construction time and ensuring cavity safety.Based on the updated design concept,five series of key technologies were proposed in site evaluation,cavern design and control,stability assessment and storage capacity parameter design,old cavern screening and utilization,and gas storage operation and monitoring.The following results were obtained from the actual application of these key technologies to the Jintan gas storage.First,the actual drilling coincidence rate of geological program is high.Second,the cavern is morphologically coincident with the design.Third,the cavern deformation retract rate is in line with the stability evaluation result.Fourth,old caverns are successfully reconstructed and utilized.Fifth,the arrangement of the monitoring network ensures the operation safety of salt-cavern underground gas storage and makes an important contribution to the peak shaving and supply guarantee of natural gas in the Yangtze River Delta region.In conclusion,the research results provide guidance for the design and engineering implementation of salt-cavern underground gas storage construction program,as well as a theoretical and technical support for the construction of similar gas storages.
基金supported by the National Key Research and Development Program of China(2023YFC3807002)。
文摘The Photovoltaic Energy storage Direct current and Flexibility(PEDF)system has attracted significant attention in recent years.In this system,charging piles,air conditioning,building energy storage,and photovoltaic are connected to the direct current bus,with flexible adjustment capabilities.The increasing presence of flexible loads complicates the calculation of electrical balance in buildings.Building energy storage is a crucial component of the PEDF system,and its storage capacity(kWh)and power(kW)are parameters that need to be determined during the design phase.This study focuses on the energy storage system of PEDF,considering both electricity and cooling storage methods,with the goal of optimizing capacity and power for economy.A dual-layer optimization model of“operational-design optimization”is proposed.The operational optimization model enables the calculation of power supply and demand balance involving multiple flexible loads over the entire year of 8760 hours.In the design optimization model,equipment investment is considered based on the operational optimization model,and particle swarm optimization(PSO)is employed to achieve the design optimization of energy storage system.This study uses a Shenzhen office building as a case study,demonstrating that the installation of battery and cooling storage facility can enhance system economic efficiency,while the scale of photovoltaic installation and time-of-use tariff significantly impact the design of building energy storage solutions.
基金This work was supported in part by the Smart Grid Joint Foundation Program of National Science Foundation of China and State Grid Corporation of China(No.U1966204)in part by National Natural Science Foundation of China(No.51907064)。
文摘With an increasing integration of intermittent distributed energy resources(DERs),the consequent voltage excursion and thermal overloading issues limit the self-sufficiency of distribution networks(DNs).The concept of soft open point(SOP)has been proposed as a promising solution to improve the hosting capacity of DNs.In this paper,considering the ability of building thermal storage(BTS)to increase the penetration of renewable energy in DNs,we provide an optimal planning framework for SOP and DER.The optimal planning model is aimed at minimizing the investment and operational costs while respecting various constraints,including the self-sufficiency requirement of the DN,SOP,building thermal storage capacity and DER operations,etc.A steady-state SOP model is formulated and linearized to be incorporated into the planning framework.To make full use of the BTS flexibility provided by ubiquitous buildings,a differential equation model for building thermal dynamics is formulated.A hybrid stochastic/robust optimization approach is adopted to depict the uncertainties in renewable energy and market prices.IEEE 33-bus feeder and a realistic DN in the metropolitan area of Caracas are tested to validate the effectiveness of the proposed framework and method.Case studies show that SOP/BTS plays a complementary and coordinated coupling role in the thermo-electric system,thereby effectively improving the hosting capacity and self-sufficiency of DNs.
文摘The presence or absence of occupants in a building has a direct effect on its energy use,as it influences the operation of various building energy systems.Buildings with high occupancy variability,such as universities,where fluctuations occur throughout the day and across the year,can pose challenges in developing control strategies that aim to balance comfort and energy efficiency.This situation becomes even more complex when such buildings are integrated with renewable energy technologies,due to the inherently intermittent nature of these energy source.To promote widespread integration of renewable energy sources in such buildings,the adoption of advanced control strategies such as model predictive control(MPC)is imperative.However,the variable nature of occupancy patterns must be considered in its design.In response to this,the present study evaluates a price responsive MPC strategy for a solar thermal heating system integrated with thermal energy storage(TES)for buildings with high occupancy variability.The coupled system supplies the building heating through a low temperature underfloor heating system.A case study University building in Nottingham,UK was employed for evaluating the feasibility of the proposed heating system controlled by MPC strategy.The MPC controller aims to optimize the solar heating system’s operation by dynamically adjusting to forecasted weather,occupancy,and solar availability,balancing indoor comfort with energy efficiency.By effectively integrating with thermal energy storage,it maximizes solar energy utilization,reducing reliance on non-renewable sources and ultimately lowering energy costs.The developed model has undergone verification and validation process,utilizing both numerical simulations and experimental data.The result shows that the solar hot water system provided 63%heating energy in total for the case study classroom and saved more than half of the electricity cost compared with that of the original building heating system.The electricity cost saving has been confirmed resulting from the energy shifting from high price periods to medium to low price periods through both active and passive heating energy storages.
