Cooling panels are increasingly used in domestic residential buildings.To provide medium temperature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity ind...Cooling panels are increasingly used in domestic residential buildings.To provide medium temperature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity independent control air-conditioning unit was developed for single residential house by utilizing multi-variable technology.First,the supply air temperature was studied to determine the proper supply air flow rate for the humidity control.Then,the energy consumption of different temperature-humidity independent control systems was studied.The analysis indicates that unity evaporating temperature can be used to handle the moisture load and sensible heat load in two evaporators.So the unit scheme was put forward.Two evaporators were used to produce medium temperature water and dry air separately,and electric expansion valves were used to control the refrigerant distribution between the two evaporators.Then,experimental work was carried out to investigate the influence of compressor frequency,refrigerant distribution on the dehumidification capacity,energy efficiency and refrigeration capacity.In the end,the paper concludes that both compressor frequency and refrigerant distribution can control the dehumidification capacity,but the former influences the EER more than the latter,while the latter influences the refrigeration capacity more than the former.We can find a proper running point at certain sensible and latent cooling load by adjusting both compressor frequency and electric expansion valve.The energy consumption of this kind of unit was estimated and compared with present room air conditioners,which shows that it can save about 41% cooling energy consumption.展开更多
This paper deals with the application of decouple Control theory to temperature and humidi-ty control in air-conditioning system. The decouple control algorithm for bivariable systems isderived applicablly for air-con...This paper deals with the application of decouple Control theory to temperature and humidi-ty control in air-conditioning system. The decouple control algorithm for bivariable systems isderived applicablly for air-conditioning system. The algorithm is used to design a temperatureand humidity computer control system for the preprocessing chamber of air-conditioning testequipment. The results of the real-time control experiments indicate that the decouple controlalgorithm is feasible, the control quality is improved and high control precision is achieved.展开更多
Temperature and humidity independent control(THIC)air-conditioning system is a promising technology.In this work,a novel temperature and humidity independent control(THIC)system is proposed,namely VMD-ACERS,which inte...Temperature and humidity independent control(THIC)air-conditioning system is a promising technology.In this work,a novel temperature and humidity independent control(THIC)system is proposed,namely VMD-ACERS,which integrates vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning system.This work establishes a novel coefficient of performance(COP)model of VMD-ACERS.The main parameters affecting the COP of conventional fan coil unit cooling system(FCUCS)and VMD-ACERS are investigated.The performance of FCUCS and VMD-ACERS are compared,and the energy-saving potential of VMD-ACERS is proved.Results indicate that,for FCUCS,the importance ranking of parameters is basically stable.However,for VMD-ACERS,the importance ranking will be affected by FCU and refrigerant.The most important parameters of VMD-ACERS are condensation temperature and permeate side pressure.On the contrary,superheating,subcooling are relatively less important parameters.For VMD-ACERS,it is not necessary to pursue the membrane with very high selectivity,because the selectivity of membrane would also be a less important parameter when it reaches 500.The COP of VMD-ACERS is higher than that of FCUCS when the permeate side pressure is higher than 8 k Pa.The VMD-ACERS solves two technical problems about power-saving and thermal comfort of conventional THIC,and can extend the application of THIC air-conditioning system.展开更多
Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and opera...Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.展开更多
The processes of heat and humidity transfer between air and water are what to be studied mainly in the paper, we put forward some main factors which influence the processes of heat and humidity transfer in the air was...The processes of heat and humidity transfer between air and water are what to be studied mainly in the paper, we put forward some main factors which influence the processes of heat and humidity transfer in the air washer. We come to the conclusion that we can change these main factors to achieve different heat and humidity transfer processes and decide processes of heat and humidity transfer of air and water with the initial temperature of spraying water in the air washer. All these results can make things convenient for the air conditioning management.展开更多
Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of...Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.展开更多
The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time de...The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.展开更多
A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to d...A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to discuss the design of fuzzy controller using common microprogrammed control unit (MCU) in detail. Based on fuzzy theory the query control tables fixed in read only memory (ROM) of MCU are established to realize the energy saving in the room temperature controller and the reasoning procedure is analyzed. The diagram of hardware design and the flow chart of software of room temperature controller are presented. The results show that the proposed method is practical and effective to achieve the energy saving goal.展开更多
基金Supported by Research Fund of the 11th 5year Sci Tech National Support Project
文摘Cooling panels are increasingly used in domestic residential buildings.To provide medium temperature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity independent control air-conditioning unit was developed for single residential house by utilizing multi-variable technology.First,the supply air temperature was studied to determine the proper supply air flow rate for the humidity control.Then,the energy consumption of different temperature-humidity independent control systems was studied.The analysis indicates that unity evaporating temperature can be used to handle the moisture load and sensible heat load in two evaporators.So the unit scheme was put forward.Two evaporators were used to produce medium temperature water and dry air separately,and electric expansion valves were used to control the refrigerant distribution between the two evaporators.Then,experimental work was carried out to investigate the influence of compressor frequency,refrigerant distribution on the dehumidification capacity,energy efficiency and refrigeration capacity.In the end,the paper concludes that both compressor frequency and refrigerant distribution can control the dehumidification capacity,but the former influences the EER more than the latter,while the latter influences the refrigeration capacity more than the former.We can find a proper running point at certain sensible and latent cooling load by adjusting both compressor frequency and electric expansion valve.The energy consumption of this kind of unit was estimated and compared with present room air conditioners,which shows that it can save about 41% cooling energy consumption.
文摘This paper deals with the application of decouple Control theory to temperature and humidi-ty control in air-conditioning system. The decouple control algorithm for bivariable systems isderived applicablly for air-conditioning system. The algorithm is used to design a temperatureand humidity computer control system for the preprocessing chamber of air-conditioning testequipment. The results of the real-time control experiments indicate that the decouple controlalgorithm is feasible, the control quality is improved and high control precision is achieved.
基金The National Key Technology Support Program(2015BAJ03B01)the Hunan Provincial Innovation Foundation for Postgraduate Studies(CX20190287)。
文摘Temperature and humidity independent control(THIC)air-conditioning system is a promising technology.In this work,a novel temperature and humidity independent control(THIC)system is proposed,namely VMD-ACERS,which integrates vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning system.This work establishes a novel coefficient of performance(COP)model of VMD-ACERS.The main parameters affecting the COP of conventional fan coil unit cooling system(FCUCS)and VMD-ACERS are investigated.The performance of FCUCS and VMD-ACERS are compared,and the energy-saving potential of VMD-ACERS is proved.Results indicate that,for FCUCS,the importance ranking of parameters is basically stable.However,for VMD-ACERS,the importance ranking will be affected by FCU and refrigerant.The most important parameters of VMD-ACERS are condensation temperature and permeate side pressure.On the contrary,superheating,subcooling are relatively less important parameters.For VMD-ACERS,it is not necessary to pursue the membrane with very high selectivity,because the selectivity of membrane would also be a less important parameter when it reaches 500.The COP of VMD-ACERS is higher than that of FCUCS when the permeate side pressure is higher than 8 k Pa.The VMD-ACERS solves two technical problems about power-saving and thermal comfort of conventional THIC,and can extend the application of THIC air-conditioning system.
文摘Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.
文摘The processes of heat and humidity transfer between air and water are what to be studied mainly in the paper, we put forward some main factors which influence the processes of heat and humidity transfer in the air washer. We come to the conclusion that we can change these main factors to achieve different heat and humidity transfer processes and decide processes of heat and humidity transfer of air and water with the initial temperature of spraying water in the air washer. All these results can make things convenient for the air conditioning management.
文摘Analyzing observations of wintertime air temperature in both indoor and outdoor surroundings in Kunming, a city lying in low latitudes, characteristics of temperature and humidity have been studied for the interior of rooms facing north-south under different weather conditions. Significant warming effect has been identified in terms of lowest and daily-mean indoor temperature in the area of Kunming. The heating amplitude ranges from 7.7C to 10.0C and from 4.6C to 5.8C for the interior part of rooms facing the south and from 4.6C to 7.0C and from 1.3C to 4.4C for the interior part of rooms facing the north, respectively for the two elements. The highest air temperature is higher indoor than outdoor for rooms facing the south, but otherwise is usually true for rooms facing the north. Additional findings point out that buildings not only help maintain relatively warm indoor temperature but delay its variation. The diurnal cycle of temperature indoor is smaller and ranges by 40% ~ 48% for south-facing rooms, and by 20% ~ 30% for north-facing rooms, than outdoor, and the highest temperature is about 2 hours late inside the room than outside. It shows how inertly indoor temperature varies. The work also finds that relative humidity is less indoor in southward rooms than in northward ones and difference is the largest on fine days but the smallest when it is overcast. For the diurnal variation, the indoor relative humidity is large at nighttime with small amplitude but small during daytime with large amplitude. The above-presented results can be served as scientific foundation for more research on climate in low-latitude cities and rational design of urban architectures.
文摘The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.
文摘A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to discuss the design of fuzzy controller using common microprogrammed control unit (MCU) in detail. Based on fuzzy theory the query control tables fixed in read only memory (ROM) of MCU are established to realize the energy saving in the room temperature controller and the reasoning procedure is analyzed. The diagram of hardware design and the flow chart of software of room temperature controller are presented. The results show that the proposed method is practical and effective to achieve the energy saving goal.