User frequency conversion distributed water mixing access system for area cooling system and method thereof

Abstract

The invention discloses a user frequency conversion distributed water mixing access system for an area cooling system and a method thereof. The system comprises distributed variable frequency water pumps, a static flow balance valve, a self-operated pressure difference control valve, a proportional integral electric valve, a temperature transmitter, a PID controller and a water mixing pipe; the distributed variable frequency water pumps are installed on a water mixing pipe or a user water supply pipe of each user according to user requirements, the proportional integral electric valve is respectively arranged on a water supply pipe-level water mixing pipe of each user branch supply cold primary side pipe network, the temperature transmitter is installed on a water return pipe of the cold water secondary side pipe network of each user, the temperature transmitter transmits detected temperature information to the PID controller, the PID controller controls the operation frequency of thevariable-frequency water pump and the valve opening degree of the proportional integral electric valve according to the detected temperature. According to the system, the water inlet flow and the pressure of the water inlet flow are adjusted to be within the working range of the proportional integral electric valve, and automatic control is facilitated.

Description

technical field [0001] The invention relates to the field of district cooling, in particular to a user frequency conversion distributed mixed water access system and method for district cooling. Background technique [0002] As a means of intensive and large-scale utilization of resources, district cooling also has the functions of "shaving peaks and filling valleys" and "improving energy utilization rate" and other energy-saving and emission-reducing functions, and is gradually being promoted in China. Different from central heating, regional cooling supplies chilled water for air conditioning, and the temperature difference between supply and return water is small. Therefore, under the same conditions, the water delivery volume is large, the energy consumption of water pump delivery and the cooling loss of the pipe network are large, and the coverage radius is small. [0003] Considering that branched pipe networks are often used in district cooling, multiple users have di...

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Problems solved by technology

Compared with the direct connection method often used in central heating, the indirect connection of plate heat exchangers is used to ensure that the main network and the user system are relatively independent, and the operating conditions and water quality do not affect each other; The ground area is large, and there is a difference in heat exchange between the fluids on both sides of the plate heat exchanger, which will inevitably cause unnecessary energy waste. In addition, the secondary pump and the user circulation pump must bear the resistance loss of the heat exchanger, which affects the operating efficiency of the system

At the same time, due to the branched pipe network, the head of the secondary pump needs to meet the pressure head of the most unfavorable user. As a result, the near-end users separated by plate replacement need to adopt decompression measures to eliminate the redundant secondary pump head, which further causes energy waste. , and increase the complexity of the system, which is not conducive to maintenance and operation management

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