Overall chilled water system energy consumption modeling and optimization

2021 ◽  
Vol 299 ◽  
pp. 117166
Author(s):  
Neal Trautman ◽  
Ali Razban ◽  
Jie Chen
2012 ◽  
Vol 614-615 ◽  
pp. 651-655
Author(s):  
Gang Wang

The article builds up the mathematics model about the fan coil chilled water system energy consumption. By the model, it calculates the energy consumption under the different flux ratio, the result shows that the optimal water parameter is different from the design parameter, it has relation with the chilled water pump head. When the pump head value is larger, adopting the smaller design flux’s parameter; when the pump head value is smaller, adopting the larger design flux’s parameter. So to make the energy consumption minimum, the water parameter should be computered.


Author(s):  
Ghanshyam Gaudani ◽  
Alex Quintal ◽  
Dragoljub Kosanovic

Chilled water systems constitute a major portion of energy consumption in air conditioning systems of the large buildings and process cooling of the manufacturing plants. These systems do not operate optimally in most of the cases because of the operating parameters set and/or the components used. The Chilled water system analysis tool software (CWSAT) is developed as a primary screening tool for energy evaluation. This tool quantifies the energy usage of the various chilled water systems and typical measures that can be applied to these systems to conserve energy. The tool requires minimum number of inputs to analyze the component-wise energy consumption and incurred overall cost. Both air-cooled and water-cooled systems can be analyzed with this tool; however, this paper focuses on water-cooled systems. The tool uses weather data of the chilled water system location and loading schedules to calculate the chilled water system energy consumption. The Air-Conditioning and Refrigeration Institute (ARI) standard 550/590 typical loading schedule is also incorporated for the chiller(s) loading. The tool is capable of comparing economics by analyzing the energy consumption and relevant cost of the existing system and the new system with cost reduction opportunities considered like: (1) increase chilled water temperature set point, (2) lowering the condenser cooing water supply temperature set point, (3) replace chiller(s), (4) Apply variable speed control to chilled and/or condenser water pumps, (5) upgrade cooling tower fan speed control, (6) Use free cooling when possible for water-cooled systems. The savings can be calculated separately for each cost reduction opportunity or can be combined. The economics comparison can be a primary decision criterion for further detailed engineering and cost analysis related with system changes. The comparison between actual system energy consumption and CWSAT results are also shown.


Author(s):  
Renata Portela de Abreu ◽  
Victor Hugo Lobo Correia ◽  
Adriano Marques ◽  
monica carvalho

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3608
Author(s):  
Yang Yuan ◽  
Neng Zhu ◽  
Haizhu Zhou ◽  
Hai Wang

To enhance the energy performance of a central air-conditioning system, an effective control method for the chilled water system is always essential. However, it is a real challenge to distribute exact cooling energy to multiple terminal units in different floors via a complex chilled water network. To mitigate hydraulic imbalance in a complex chilled water system, many throttle valves and variable-speed pumps are installed, which are usually regulated by PID-based controllers. Due to the severe hydraulic coupling among the valves and pumps, the hydraulic oscillation phenomena often occur while using those feedback-based controllers. Based on a data-calibrated water distribution model which can accurately predict the hydraulic behaviors of a chilled water system, a new Model Predictive Control (MPC) method is proposed in this study. The proposed method is validated by a real-life chilled water system in a 22-floor hotel. By the proposed method, the valves and pumps can be regulated safely without any hydraulic oscillations. Simultaneously, the hydraulic imbalance among different floors is also eliminated, which can save 23.3% electricity consumption of the pumps.


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