Development and Application of the Control Technology for VAV Air-Conditioning System

2011 ◽  
Vol 374-377 ◽  
pp. 543-546
Author(s):  
Shi Zhong Yang ◽  
Qing Chang Ren ◽  
Xia Li
Keyword(s):  
Air Conditioning ◽  
Large Scale ◽  
Control Strategies ◽  
Hot Spot ◽  
Time Lag ◽  
Water System ◽  
Developed Countries ◽  
Research Progress ◽  
Air Conditioning System ◽  
Saving Effect

The variable air volume (VAV) air-conditioning system with its superior energy saving effect has been applied in many developed countries, also drawn more and more attention in China. Due to the characteristics of VAV air-conditioning system are nonlinear, large time lag, strong coupling, multi-variable and multi-disturbance, the control complexity of the VAV system increase greatly. The energy conservation and comfort of the VAV air-conditioning system can not fully been embodied in application. The research on the VAV system has become the hot spot in the science and technology workers, many new methods and strategies have emerged. From the three aspects: the air system, the water system and the large scale system, the paper describes the control strategies, the control methods and the research progress about the VAV air-conditioning system.

Application of the Self-Adjusting Fuzzy Control in Water System of Central Air-Conditioner for Saving Energy

2014 ◽  
Vol 1070-1072 ◽  
pp. 2010-2016 ◽  
Author(s):  
Yuan Yuan Zhang ◽  
Yu Nong Shen
Keyword(s):  
Air Conditioning ◽  
Fuzzy Controller ◽  
Control Strategies ◽  
Water System ◽  
Response Speed ◽  
The Self ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Central Air Conditioning ◽  
Saving Effect

Central air conditioning system with multi variable, nonlinear, time-varying, large time-delay characteristics using the traditional control strategy is difficult to control and good energy saving effect. For these features of central air conditioning system, self-adjustment fuzzy controller is studied based on the fuzzy controller. The simulation can be seen, the self-adjustment fuzzy controller has a faster response speed and smaller steady-state error, while there is a certain adaptive capacity. Its control performance is superior to conventional control strategies and conventional fuzzy controller. Central air-conditioning system uses the parameter self-adjusting fuzzy controller strategy combined with inverter technology. According to load changes, central air conditioning water system can automatically real-timely control the pumps to ensure that the comfort of central air-conditioning provided a significant reduction in energy consumption.

Modeling and Simulation of Chilled Water System for Central Air Conditioning

2012 ◽  
Vol 204-208 ◽  
pp. 4280-4285 ◽  
Author(s):  
Jian Min Sun ◽  
Chun Dong Zhang ◽  
Ze Yang Zhou
Keyword(s):  
Control System ◽  
Energy Saving ◽  
Pid Control ◽  
Air Conditioning ◽  
Water System ◽  
Air Conditioning System ◽  
Chilled Water ◽  
Central Air Conditioning ◽  
Chilled Water System ◽  
Saving Effect

Considering the central air conditioning system is highly susceptible to interferences from external environment, this paper established a dynamic mathematical model for chilled water system with the air conditioning area, fan coil unit and air conditioning area interference factors. Selection of chilled water system as a controlled object, designed the energy saving control system for central air-conditioning. The inputs of PID controller are deviation of actual temperature and setting temperature, and the change rate of the deviation; output is operation frequency of pump. Experiment shows that, PID control system in 90% time operating at a frequency of 10Hz-40Hz, average is 32.5Hz. Compared with no control system, the pump power consumption was reduced 33.9%.In conclusion, PID control in the central air conditioning system have a good energy saving effect.

Optimal Control Strategy for Ice-Storage System Based on Hourly Dynamic Load Simulation

2013 ◽  
Vol 671-674 ◽  
pp. 2515-2519
Author(s):  
Xue Mei Wang ◽  
Zhen Hai Wang ◽  
Xing Long Wu
Keyword(s):  
Optimal Control ◽  
Air Conditioning ◽  
Control Strategies ◽  
Storage System ◽  
Simulation Software ◽  
Ice Storage ◽  
Optimal Control Strategy ◽  
Air Conditioning System ◽  
Energy Plus ◽  
Load Simulation

This project aims to study the optimal control model of the ice-storage system which is theoretically close to the optimal control and also applicable to actual engineering. Using Energy Plus, the energy consumption simulation software, and the simple solution method of optimal control, researchers can analyze and compare the annual operation costs of the ice-storage air-conditioning system of a project in Beijing under different control strategies. Researchers obtained the power rates of the air-conditioning system in the office building under the conditions of chiller-priority and optimal contro1 throughout the cooling season. Through analysis and comparison, they find that after the implementation of optimal control, the annually saved power bills mainly result from non-design conditions, especially in the transitional seasons.

Application Study of Load Forecasting of Central Air-Conditioning System Based on Time Sequence Analysis Method

2012 ◽  
Vol 220-223 ◽  
pp. 622-625
Author(s):  
Xue Li Zhu ◽  
Bo Dong ◽  
Yong Jun Zhu
Keyword(s):  
Sequence Analysis ◽  
Air Conditioning ◽  
Time Lag ◽  
Load Forecasting ◽  
Time Sequence ◽  
Analysis Method ◽  
Air Conditioning System ◽  
Central Air Conditioning ◽  
Heating Load ◽  
Time Sequence Analysis

With the characteristics of non-stationarity, non-linearity, time-lag of refrigeration/ heating supplying in minds, load forecasting of central air-conditioning system is carried using time sequence analysis method. Firstly, acquisition sample data of central air-conditioning system is pretreated, and random time sequence AR model of system is formulated. Then, forecasting of AR refrigeration/heating load based on Yule-walker method is conducted. In order to enhance forecasting accuracy, crossover forecasting is introduced into the load forecasting, that is, to use vertical forecasting to follow household demands for load and horizontal forecasting to track changes of weather. Then, weight cross is made to vertical and horizontal forecasting results. Finally, refrigeration/heating load forecasting software of central air-conditioning system is developed, which is used in energy-saving monitoring and control of central air-conditioning system.

Air Conditioning System Water Quality and Equipment Condition Investigation and Analysis of Energy Saving Measures

2012 ◽  
Vol 516-517 ◽  
pp. 1224-1228
Author(s):  
Na Liang ◽  
Rui Li
Keyword(s):  
Energy Saving ◽  
Air Conditioning ◽  
Water System ◽  
Building Energy ◽  
Development Trend ◽  
Air Conditioning System ◽  
Effective Utilization ◽  
Energy Saving Potential ◽  
Central Air Conditioning ◽  
Points Of View

Due to energy reserves reduces gradually and uneven distribution, all countries pay more and more attention to energy saving and improve the effective utilization of energy, China also attaches great important to this. Energy saving of buildings is a necessary development trend. Air conditioning system as a large important part of building energy consumption has a huge energy-saving potential. This article mainly introduced the related strategies of energy saving in central air conditioning water system from the following three points of view: the water treatment, the cooling tower, and the variable frequency pump.

Energy-saving effect of utilizing recirculated air in electric vehicle air conditioning system

2019 ◽  
Vol 102 ◽  
pp. 122-129 ◽  
Author(s):  
Leyan Pan ◽  
Cichong Liu ◽  
Ziqi Zhang ◽  
Tianying Wang ◽  
Junye Shi ◽  
...  
Keyword(s):  
Energy Saving ◽  
Electric Vehicle ◽  
Air Conditioning ◽  
Air Conditioning System ◽  
Saving Effect

scholarly journals Simplified Thermal Model and Optimal Control for Chilled Water Pipe in Air-Conditioning System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhida Zhao ◽  
Nanyang Yu ◽  
Tao Yu ◽  
Lisha Ye
Keyword(s):  
Control Strategy ◽  
Thermal Model ◽  
Air Conditioning ◽  
Thermal Characteristic ◽  
State Space Model ◽  
Water System ◽  
Water Pipe ◽  
Preview Control ◽  
Air Conditioning System ◽  
Chilled Water

As an important subsystem in air-conditioning system, water system connects the chiller and terminal equipment. Therefore, it is necessary to develop an accurate thermal model for chilled water pipe to create the suitable indoor temperature and humidity environment. In this paper, the thermal model of the pipe was considered by utilizing the simplified thermal time-delay state-space model with the mass, energy balance, and heat consumption equations. Based on this improved model, the preview control as control strategy for water pipe temperature was proposed, and its robustness and stability were discussed. Subsequently, the performances of this model and control strategy were tested in a fan-coil system simulating with MATLAB and TRNSYS (Transient System Simulation Program). Explicitly, the results show that this model accurately predicts the thermal characteristic, and the average mean squared errors for water temperature were 11.14% and 12.82%, respectively. Meanwhile, the tracking effect of valve controller was better than the control strategy with no preview control.

scholarly journals Dynamic simulation of indirect air conditioning systems with optimized computational time

2019 ◽  
Vol 111 ◽  
pp. 04042
Author(s):  
Nicolás Ablanque ◽  
Santiago Torras ◽  
Carles Oliet ◽  
Joaquim Rigola ◽  
Carlos-David Pérez-Segarra
Keyword(s):  
Air Conditioning ◽  
Energy Savings ◽  
Control Strategies ◽  
Model Potential ◽  
Hvac Systems ◽  
Object Oriented Programming ◽  
Computational Time ◽  
Air Conditioning System ◽  
Numerical Resolution ◽  
Air Conditioning Systems

The simulation of HVAC systems is a powerful tool to improve the energy efficiency in buildings. The modelling of such systems faces several obstacles due to both the physical phenomenology present and the numerical resolution difficulties. The present work is an attempt to develop a robust, fast, and accurate model for HVAC systems that can interact with the other relevant systems involved in buildings thermal management. The whole system model has been developed in the form of libraries under the Modelica language to exploit its advantageous characteristics: object-oriented programming, equationbased modelling, and handling of multi-physics. The global resolution is carried out dynamically so that not only steady-state predictions can be conducted but also control strategies can be studied over meaningful periods of time. This latter aspect is crucial for optimizing energy savings. The libraries include models for all the system individual components such as pumps, compressors or heat exchangers (operating with twophase flows and/or moist air) and also models assemblies to account for vapour compression units and liquid circuits. An illustrative example of an indirect air conditioning system is detailed in the present work in order to highlight the model potential.

scholarly journals Apple harvesting robot under information technology: A review

2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092531 ◽  
Author(s):  
Weikuan Jia ◽  
Yan Zhang ◽  
Jian Lian ◽  
Yuanjie Zheng ◽  
Dean Zhao ◽  
...  
Keyword(s):  
Information Technology ◽  
Control Strategies ◽  
Hot Spot ◽  
Operation Mode ◽  
Research Progress ◽  
Clear Understanding ◽  
Intelligent Computing ◽  
Operation Process ◽  
Harvesting Efficiency ◽  
Harvesting Robot

It has been more than 30 years since the French pioneered the research of the apple harvesting robot, and with the joint efforts of scholars all around the world, a variety of prototypes have been developed. However, the existing apple harvesting robot prototype is still in the experimental research stage because of its low harvesting efficiency. With the help of information technology, the related research has ushered in a milestone development, and it is full of opportunities and challenges for apple harvesting robotic researchers. In this article, it briefly introduced the development history, structure, and composition of apple harvesting robots and the operation process, which makes readers have a clear understanding of apple harvesting robot and its harvesting principle. Then systematically summarizing the research results of apple harvesting robots both at domestic and at foreign, we carried out in following three aspects: rapid and accurate recognition and positioning of target fruit, all-weather operation mode, and application of intelligent computing theory in apple harvesting robots, and it analyzes the research progress of apple harvesting robot in detail. The results show that improving the harvesting efficiency is the key and hot spot for the research on apple harvesting robots. Under the impetus of information technology, how to achieve fast and accurate recognition of the fruits of multienvironment and multiple information, obtain reasonable path planning, and further optimization of control strategies are all important research directions.

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