Circulating water heating system of secondary pump

Abstract

The invention provides a circulating water heating system of a secondary pump, consisting of a heating medium water inlet pipe, a heating medium water return pipe, a heat exchanger, a primary pump, a secondary pump, a bypass flow water mixer, a temperature control valve, a control cabinet and a tail-end heat user. The circulating water heating system is characterized in that the heating medium water inlet pipe is connected with a primary side inlet of the heat exchanger through the temperature control valve; the heating medium water return pipe is connected with the primary side outlet of the heat exchanger; a secondary side outlet of the heat exchanger is connected with a primary water inlet of the bypass flow water mixer through the primary water supply pipe; the primary water outlet of the bypass flow mixer is connected with the primary pump through the primary water return pipe and than is butted with a secondary side inlet of the heat exchanger. The invention adopts the primary pump constant flow and the secondary pump constant flow to operate so as to ensure that the system can automatically adapt to the load change of the tail-end heat user, controls the water supply temperature of the primary water supply pipe by matching outdoor temperature variation, and has the characteristics of reasonable design, reliable operation, high efficiency, energy saving, capability of automatically adapting to the flow variation of the secondary side tail-end heat user, and the like. The invention is particularly suitable for large and medium circulating water heating systems.

Description

1. Technical field [0001] The invention relates to a circulating water heating system, in particular to a secondary pump circulating water heating system for indirect heat exchange with a heat medium. 2. Background technology [0002] Most of the circulating water heating systems in the prior art are in the primary pump circulating water heating mode, that is, a primary circulating water pump is used for pressurized circulation on the secondary side of the heat exchanger, and the circulating water pump is controlled by constant flow or variable flow. When the circulating water pump adopts constant flow control, there is high energy consumption in operation, and it is not convenient for household metering or the variable flow demand of end heat users; when the circulating water pump adopts variable flow control, that is, the secondary side circulating water has a variable flow throughout the process. In this way, the flow rate through the secondary side of the heat exchanger ...

AI Technical Summary

Problems solved by technology

[0002] Most of the circulating water heating systems in the prior art are in the primary pump circulating water heating mode, that is, a primary circulating water pump is used for pressurized circulation on the secondary side of the heat exchanger, and the circulating water pump is controlled by constant flow or variable flow. When the circulating water pump adopts constant flow control, there is high energy consumption in operation, and it is not convenient for household metering or the variable flow demand of end heat users; when the circulating water pump adopts variable flow control, that is, the secondary side circulating water has a variable flow throughout the process. In this way, the flow rate through the secondary side of the heat exchanger also changes with the change of the circulating water flow rate, and the change of the flow rate of the heat exchanger will affect its heat transfer coefficient. When the flow rate of the heat exchanger is small, its heat transfer coefficient is small , the heat exchange efficiency of the heat exchanger is low, and in large and medium-sized circulating water systems, if the system is operated at part load or small load, it is easy to cause secondary side "small temperature difference, large flow, high point consumption" and secondary Hydraulic imbalance of the secondary side circulation pipe network

In order to overcome the problems of high lift and high pump power of the primary circulating water pump, a few secondary circulating water pumps are connected in series in the secondary side circulating water system. In fact, the pumping head of a system is completely divided into the primary pump and the primary pump. Compared with the primary pump circulating water system, the partial pressure operation of the secondary pump series circulation only simply reduces the head of the circulating water pump, but correspondingly increases the initial investment and failure points of the circulating water pump and the control system, and increases the system complexity

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