Research on variable pressure difference control method based on terminal load monitoring

Since the air conditioning water system always runs under partial load, a pipeline network pressure difference control strategy is proposed, which can meet the most unfavorable thermodynamic terminal demand. It can detect the required flow and pressure difference of all the terminals through real-time load monitoring. This method is applied to a district cooling and heating system. The best operating temperature difference of each terminal is obtained by investigation, and the thermal stability time is determined by the experimental test. A hydraulic model of the loop pipe network of the case is built, and the constant pressure difference and the variable pressure difference control strategies are compared. The results show that the variable pressure difference control strategy keeps the valve opening of the terminal at about 90%. Compared with the constant pressure difference control strategy, the temperature difference between supply and return water increases 1 ℃, the energy consumption of the distribution system of water pumps decreases by 24.8%, which effectively realizes energy conservation and pollution emission reduction.