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.

Mixed Programming Using FORTRAN and VB of Pipe Network for Heating and Air Condition Water System

2012 ◽  
Vol 610-613 ◽  
pp. 2478-2482
Author(s):  
Yang Cui ◽  
Lei Huang
Keyword(s):  
Air Conditioning ◽  
Simulation Analysis ◽  
Water System ◽  
Pipe Network ◽  
Air Conditioning System ◽  
Mixed Programming ◽  
Simulating Analysis ◽  
Chilled Water ◽  
Fortran Language ◽  
Chilled Water System

As the scale of the air conditioning system is constantly increasing, some problems still exist and remain to be solved in the chilled water system. Among them, the leading problems lie in the insufficient research of the overall character on the user side and lack of simulation analysis. Corresponding calculating procedures are mixed programmed using VB and FORTRAN language to conduct to simulating analysis, to testify reliability and feasibility of the method.

Mixed Programming Using VB and FORTRAN of Pipe Network for Heating and Air Condition Water System

2012 ◽  
Vol 170-173 ◽  
pp. 2564-2567
Author(s):  
Huai Ming Ning ◽  
Guo Feng
Keyword(s):  
Air Conditioning ◽  
Water System ◽  
Pipe Network ◽  
Air Conditioning System ◽  
Mixed Programming ◽  
Simulating Analysis ◽  
Chilled Water ◽  
Fortran Language ◽  
Chilled Water System

Heating and Air Condition, Pipe Network, VB,FORTRAN,Mixed Programming Abstract:As the scale of the air conditioning system is constantly increasing, some problems still exist and remain to be solved in the chilled water system. Among them, the leading problems lie in the insufficient research of the overall character on the user side and lack of simualtion analysis. Corresponding calculating procedures are Mixed programmed using VB and FORTRAN language to conduct to simulating analysis, to testify reliability and feasibility of the method.

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.

Lifecycle Cost Analysis for Better Air Conditioning Choice in Kuwait Residential Sector

2015 ◽  
Author(s):  
Hamad H. Almutairi ◽  
Jonathan Dewsbury ◽  
Gregory F. Lane-Serff
Keyword(s):  
Cost Analysis ◽  
Air Conditioning ◽  
Water System ◽  
Cost Effective ◽  
Electrical Energy ◽  
Direct Expansion ◽  
Air Conditioning System ◽  
Residential Sector ◽  
Chilled Water ◽  
Chilled Water System

Residential air conditioning consumes a huge amount of the produced electrical power from fossil fuel power plants in Kuwait. Energy availability and the consequences on Kuwait’s expenditure associated with producing electricity is a hot topic in this oil producing country. The predominant air conditioning type in Kuwait’s residential sector is packaged direct expansion. An intention to shift to chilled water air conditioning system for future’s houses was announced as a promising solution to save energy. This work is presented to demonstrate how lifecycle cost analysis can be performed to underline tentative issues before shifting to a new air conditioning system for houses in Kuwait. No previous attempts have been made to assess the feasibility of chilled water air conditioning system for houses in Kuwait based on lifecycle cost analysis. The work considered the air conditioning requirements for a block of six typical houses as a baseline for the evaluation. The total cooling load of the studied block of houses was used to estimate the annual electrical energy associated with each air conditioning alternative. This was made by the help of DOE EnergyPlus thermal simulation engine through its interface with DesignBuilder software. Actual financial inputs were penetrated in the analysis; which includes installation, operation and maintenance costs for each studied air conditioning alternative. It was found that chilled water system can conserve about 40% of the annual electrical energy required to operate packaged direct expansion air conditioning. But, due to high installation cost, chilled water system is not cost effective for consumers. The outcomes from the lifecycle cost analysis indicated that it would be cost effective for the government to subsidy the installation of chilled water systems for consumers. This will help to conserve electrical energy associated with conventional systems that are currently in use.

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