Abstract--Vapor compression refrigeration cycle （VCC） system is a high dimensional coupling thermodynamic system for which the controller design is a great challenge. In this paper, a model predictive control based ...Abstract--Vapor compression refrigeration cycle （VCC） system is a high dimensional coupling thermodynamic system for which the controller design is a great challenge. In this paper, a model predictive control based energy efficient control strategy which aims at maximizing the system efficiency is proposed. Firstly, according to the mass and energy conservation law, an analysis on the nonlinear relationship between superheat and cooling load is carried out, which can produce the maximal effect on the system performance. Then a model predictive control （MPC） based controller is developed for tracking the calculated setting curve of superheat degree and pressure difference based on model identified from data which can be obtained from an experimental rig. The proposed control strategy maximizes the coefficient of performance （COP） which depends on operating conditions, in the meantime, it meets the changing demands of cooling capacity. The effectiveness of the control performance is validated on the experimental rig. Index Terms--Cooling load, model predictive control （MPC）, superheat, vapor compression refrigeration cycle （VCC）.展开更多
DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate ...DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.展开更多
Several important developing phases of the formulas for mobility calculation based on constraints are introduced. The shortcoming of the mobility formulas based on common constraints of loops of a mechanism is that vi...Several important developing phases of the formulas for mobility calculation based on constraints are introduced. The shortcoming of the mobility formulas based on common constraints of loops of a mechanism is that virtual constraints must be calculated before determining the mobility of a mechanism with virtual constraints. In order to avoid the shortcoming, some new concepts including virtual loop, virtual-loop constraint and general-kinematic-pair constraint are used to analyze the relationship between mobility of links and constraint of kinematic pairs and a mobility formula based on common constraints of virtual loops is proposed. The formula is that the number of mobility of a mechanism is the sum of mobility of all links in the mecha-nism minus the sum of constraints of all kinematic pairs plus the sum of the common constraints of all virtual loops. The sum of over constraints of a mechanism is the sum of constraints of all virtual loops in the mechanism. This mobility formula expressed in terms of common constraints of virtual loops in a mechanism can avoid calculating virtual constraints. It is proved that the new formula is correct, simple and effective through the analysis of several different kinds of mechanisms.展开更多
The deep overflow through the Luzon Strait drives the cyclonic deep circulation in the South China Sea(SCS). In the mean time, the intruding Pacific deep water transforms and upwells due to enhanced diapycnal mixing i...The deep overflow through the Luzon Strait drives the cyclonic deep circulation in the South China Sea(SCS). In the mean time, the intruding Pacific deep water transforms and upwells due to enhanced diapycnal mixing in the SCS. Both processes greatly contribute to the SCS meridional overturning circulation(SCSMOC). At the same time, both the deep circulation and meridional overturning circulation are modulated by rough topography in the SCS. Furthermore, the spatial structure of the SCSMOC infers a link between the upper-layer circulation and deep circulation in the SCS. This paper reviews recent advances in the SCS deep circulation and meridional overturning circulation, including the driving mechanism of the SCS deep circulation and its modulation by topography, as well as the spatial structure of the SCSMOC and its dynamical mechanism.展开更多
基金supported by the National Natural Science Foundation of China(61233004,61221003,61374109,61473184,61703223,61703238)the National Basic Research Program of China(973 Program)(2013CB035500)+1 种基金Shandong Provincial Natural Science Foundation of China(ZR2017BF014,ZR2017MF017)the National Research Foundation of Singapore(NRF-2011,NRF-CRP001-090)
文摘Abstract--Vapor compression refrigeration cycle （VCC） system is a high dimensional coupling thermodynamic system for which the controller design is a great challenge. In this paper, a model predictive control based energy efficient control strategy which aims at maximizing the system efficiency is proposed. Firstly, according to the mass and energy conservation law, an analysis on the nonlinear relationship between superheat and cooling load is carried out, which can produce the maximal effect on the system performance. Then a model predictive control （MPC） based controller is developed for tracking the calculated setting curve of superheat degree and pressure difference based on model identified from data which can be obtained from an experimental rig. The proposed control strategy maximizes the coefficient of performance （COP） which depends on operating conditions, in the meantime, it meets the changing demands of cooling capacity. The effectiveness of the control performance is validated on the experimental rig. Index Terms--Cooling load, model predictive control （MPC）, superheat, vapor compression refrigeration cycle （VCC）.
文摘DAR （diffusion absorption refrigeration） cycle is driven by heat and has no moving parts. It is based on refrigerant and absorbent as the working fluid together with hydrogen as an auxiliary inert gas. To circulate the working fluid without a mechanical pump, the diffusion absorption cycle relies on a bubble pump. Experimental system was designed and operated. Its aim was to investigate the performance of a bubble pump operating with three lifting tubes. The experimental results of the system were compared to existing models. The comparison showed that there was a bad agreement between the experimental and the theoretical results.
基金supported by the Natural Science Foundation of Hebei Province of China (Grant No. E2011203193)
文摘Several important developing phases of the formulas for mobility calculation based on constraints are introduced. The shortcoming of the mobility formulas based on common constraints of loops of a mechanism is that virtual constraints must be calculated before determining the mobility of a mechanism with virtual constraints. In order to avoid the shortcoming, some new concepts including virtual loop, virtual-loop constraint and general-kinematic-pair constraint are used to analyze the relationship between mobility of links and constraint of kinematic pairs and a mobility formula based on common constraints of virtual loops is proposed. The formula is that the number of mobility of a mechanism is the sum of mobility of all links in the mecha-nism minus the sum of constraints of all kinematic pairs plus the sum of the common constraints of all virtual loops. The sum of over constraints of a mechanism is the sum of constraints of all virtual loops in the mechanism. This mobility formula expressed in terms of common constraints of virtual loops in a mechanism can avoid calculating virtual constraints. It is proved that the new formula is correct, simple and effective through the analysis of several different kinds of mechanisms.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB06020102)the National Natural Science Foundation of China (Grant Nos. 41276024 & 91228202)+1 种基金the Knowledge Innovation Engineering Frontier Project of the Sanya Institute of Deep Sea Science and Engineering (Grant No. SIDSSE-201205)the project of Guangdong Provincial Department of Science and Technology (Grant No. 2012A032100004)
文摘The deep overflow through the Luzon Strait drives the cyclonic deep circulation in the South China Sea(SCS). In the mean time, the intruding Pacific deep water transforms and upwells due to enhanced diapycnal mixing in the SCS. Both processes greatly contribute to the SCS meridional overturning circulation(SCSMOC). At the same time, both the deep circulation and meridional overturning circulation are modulated by rough topography in the SCS. Furthermore, the spatial structure of the SCSMOC infers a link between the upper-layer circulation and deep circulation in the SCS. This paper reviews recent advances in the SCS deep circulation and meridional overturning circulation, including the driving mechanism of the SCS deep circulation and its modulation by topography, as well as the spatial structure of the SCSMOC and its dynamical mechanism.
