A coordinate control approach for energy saving of central variable- frequency air conditioning systems

Author(s):  
Kuei-I Tsai ◽  
Ching-Chih Tsai
Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 81
Author(s):  
Rongjiang Ma ◽  
Shen Yang ◽  
Xianlin Wang ◽  
Xi-Cheng Wang ◽  
Ming Shan ◽  
...  

Air-conditioning systems contribute the most to energy consumption among building equipment. Hence, energy saving for air-conditioning systems would be the essence of reducing building energy consumption. The conventional energy-saving diagnosis method through observation, test, and identification (OTI) has several drawbacks such as time consumption and narrow focus. To overcome these problems, this study proposed a systematic method for energy-saving diagnosis in air-conditioning systems based on data mining. The method mainly includes seven steps: (1) data collection, (2) data preprocessing, (3) recognition of variable-speed equipment, (4) recognition of system operation mode, (5) regression analysis of energy consumption data, (6) constraints analysis of system running, and (7) energy-saving potential analysis. A case study with a complicated air-conditioning system coupled with an ice storage system demonstrated the effectiveness of the proposed method. Compared with the traditional OTI method, the data-mining-based method can provide a more comprehensive analysis of energy-saving potential with less time cost, although it strongly relies on data quality in all steps and lacks flexibility for diagnosing specific equipment for energy-saving potential analysis. The results can deepen the understanding of the operating data characteristics of air-conditioning systems.


Author(s):  
Jéssica Duarte ◽  
Lara Werncke Vieira ◽  
Rafael Zanardo ◽  
Augusto Delavald Marques ◽  
Paulo Smith Schneider

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Yan Zhang ◽  
Xiaoli Chu ◽  
Yongqiang Liu

Chilled water system of central air conditioning is a typical hybrid system; variable frequency behavior with amplitude limited of pumps reflects continuous and discrete dynamic characteristics. The way of energy-saving is variable water volume, via variable frequency behavior of pumps to gain adjustment of power consumption. Facing the situation of the variable frequency pumps with parallel operation, single continuous or discrete modeling cannot reflect the hybrid features. Thus, the control method will have some questions, such as bad energy-saving effect, difficult accurate adjustment of cold capacity, and low running energy efficiency. However, hybrid system modeling can reflect hybrid dynamic behavior of pumps, which is combining continuous and discrete features. The questions of nonlinear and multiparameters can be solved by control method based on hybrid system. Here, an optimum control method is proposed with the principle of the minimum, by setting the minimum power consumption as the performance function in fixed time, which realizes variable control of pumps and accurate adjustment of temperature inside room. At last, it shows the system characteristics and energy-saving affection by hybrid system modeling and the optimum control method.


2020 ◽  
Vol 10 (4) ◽  
pp. 1513 ◽  
Author(s):  
Daniel Sánchez-García ◽  
David Bienvenido-Huertas ◽  
Jesús A. Pulido-Arcas ◽  
Carlos Rubio-Bellido

Reports of Intergovernmental Panel on Climate Change have set various greenhouse gas emissions scenarios, through which the evolution of the temperature of the planet can be estimated throughout the 21st century. The reduction of the emissions from the different activities carried out by mankind is crucial to mitigate greenhouse gas emissions. One of the most significant activities is users’ behaviour within buildings, particularly the use of Heating, Ventilation and Air-Conditioning systems. Modifying users’ behaviour patterns to guarantee acceptable thermal conditions inside buildings could lead to considerable energy saving percentages, and adaptive thermal comfort models could be an opportunity to achieve important savings. For this reason, this study analyzes the potential to apply adaptive thermal comfort models to use artificial air-conditioning systems by modifying setpoint temperatures. The analysis was conducted in five major European cities (Barcelona, Berlin, Bern, Rome, and Vienna) and in five climate change scenarios in the year 2050. The results showed that, in general, the energy saving achieved by adaptive strategies was larger in the cities with a greater cooling demand. Also, in both Representative Concentration Pathways (RCP) of the Fifth Assessment Report (AR5) considered, the energy saving were decreased in the cities of Barcelona and Rome, with values lower than those of the Fourth Assessment Report (AR4) scenarios considered, whereas in the cities of Berlin, Bern, and Vienna, the saving in the RCP scenarios is greater than those in the other scenarios.


2014 ◽  
Vol 945-949 ◽  
pp. 2629-2632
Author(s):  
Ze Qin Liu ◽  
Zhen Jing Wu

This paper setup the hybrid automata control model of variable-frequency air conditioning by adopting Stateflow simulation toolbox of Matlab. The regulated quickness of the hybrid automata control model was simulated and validated by comparing PID control in Simulink. The hybrid automata control strategy was proposed in this paper for exploring hybrid features of the frequency conversion air conditioning control system. Comparing the traditional PID model, the result indicated the convergence speed of hybrid automata control strategy was faster to control the compressor operating frequency, better to simulate indoor energy balance, and to control the operation frequency state of the compressor. The paper showed the control strategy of hybrid automata control could achieve temperature control better, and the studied model has the better effects.


2021 ◽  
Author(s):  
Mohamed Elhelw ◽  
Wael M. El-Maghlany ◽  
Mohamed Shawky Ismail ‎

Abstract This paper introduces novel modification for conventional air conditioning systems through utilizing a thermal ice storage system integrated with solar panels. Alexandria and Aswan, cities in Egypt, are chosen to represent two climates for hot-humid and hot-dry climates respectively. The governing equations for both heat and mass transfer are theoretically solved. Exergy analysis is performed for the proposed solar-ice thermal storage system via determining exergy destruction on ice and solar components as well as the total destruction based on transient analysis. This study was carried out on two common types of air conditioning systems, an air handling unit and fan coil unit. Results showed that, solar-ice storage system is more effective approach in hot-humid climate than hot-dry climate and more efficient with all-water air conditioning system than with all-air conditioning system. The maximum energy saving is 205.16 GJ having a percent of 27.5% in August for all water system in case of Alexandria city and 224.67 GJ with a percent of 25.38% in August for all-water system in case of Aswan city. All air system simulation showed maximum energy saving of 175.05 GJ with a percent of 18.13 % in case of August for Alexandria and 175.45 GJ having a percentage of 17.43% in case of Aswan in August. Moreover, the all-water system achieved a reduction in CO2 emissions by 467 tons/year in Aswan city and 390 tons/year in case of Alexandria city. While these reductions decrease to be 435 and 353 tons/year when the all-air system used for the same two cities.


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