Optimal Pump Speed Control in a Chilled Water System

Author(s):  
Bin Zheng ◽  
Mingsheng Liu

Traditionally, chilled water pump speed is modulated to maintain the water loop differential pressure set point and the control valve at the air handling unit (AHU) is modulated to maintain the supply air temperature. This paper introduces a new VFD pump speed control algorithm, optimal pump head control strategy. The algorithm focuses on minimizing the water loop differential pressure in order to reduce the overall pump energy consumption. The new algorithm is implemented in a real chilled water system. The pump power consumption is compared between the traditional algorithm and new algorithm. The implementing result demonstrates that the new algorithm results in improved pump efficiency, reduced pump head and pump speed and remarkable energy savings.

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):  
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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