An energy-saving oriented air balancing method for demand controlled ventilation systems with branch and black-box model. (15th April 2020)

• Record Type: Journal Article
• Authors: Cui, Can; Zhang, Xin; Cai, Wenjian
• Is Part Of: Applied energy. Volume 264(2020)
• Publication Date: 2020-04-15
• Subjects: Demand controlled ventilation system -- Over-ventilation -- Energy efficiency -- Air balancing -- Black-box -- Radial basis function; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2020.114734
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: A novel energy-saving oriented air balancing method is proposed for DCV systems. A simple and effective branch and black-box (B 2 ) model is proposed for air balancing. Detailed physical duct system information is not required in the proposed method. The air balancing accuracy is greatly improved by the proposed method. The over-ventilation problem and its related energy waste issues are both solved. Abstract: This paper proposes an energy-saving oriented air balancing method based on a branch and black-box (B 2 ) model for multi-zone demand controlled ventilation (DCV) systems. The proposed method can achieve accurate air flow control in each zone, which avoids unnecessary energy consumption caused by over-ventilation. The operating procedures of the proposed method are as follows: Building the B 2 model for the DCV system → Predicting the terminal static pressures under the given zone design flow values → Determining the damper angles of each zone based on the static pressure predictions. In the proposed air balancing method, the basic modelling unit is the duct branch, instead of the internal fittings in the previous model-based air balancing method. Therefore, the proposed method does not need to know the complicated fitting information (e.g., elbows, transitions, dampers, etc., ) in its modelling process and therefore becomes much simpler. In addition, the complexity of the proposed B 2 model is also greatly reduced since it is independent with the fitting numbers and does not need to calculate the fitting loss coefficients. Furthermore, the radial basis function (RBF) kernel is also utilized in the proposed method to guarantee the air balancing accuracy. Compared with the existing air balancing methods, the proposed method is more efficient and effective in practice. In the lab, the proposed air balancing method was validated on a real DCV system of 5 zones under various design flow conditions. The experimental results verified the effectiveness of the proposed method on both the air balancing control accuracy and the energy saving ability.