Direct-flow type solar water-heating system and its water-flow control method

Abstract

A single flow solar water heating system includes heat storage water tank, heating collector, water circulating pump, temperature measuring set at heating collector outlet, and flow control unit connected with water circulating pump. Said system water flow control method includes according to preset heating collector outlet temperature T1 controlling said system water circulating pump working for controlling flow rate and keeping heating collector outlet temperature constant, when heating collector outlet temperature T1 >= upper temperature limit T (on), flow control unit controlling water circulating pump operation and according to heating collector temperature variation regulating water circulating pump flow rate making heating collector outlet water temperature constant as preset upper temperature limit T, when heating collector outlet temperature T1 <= preset lower temperature limit T (OFF), flow control unit stopping working and water circulating pump stopping operation. The present invention can effectively raise solar water heating system collection efficiency and prolong service life.

Description

technical field [0001] The invention belongs to the technical field of solar energy application, and in particular relates to a direct-flow solar water heating system and a water flow control method thereof. Background technique [0002] In the existing direct-flow solar water heating system, the water flow control method is to control the start and stop of the circulating water pump according to the preset temperature at the outlet of the heat collector, so as to provide hot water to the hot water storage tank. When the temperature at the outlet of the collector reaches the preset temperature, the circulating water pump starts to run, and the temperature at the outlet of the collector will rise gradually, and then it will far exceed the preset temperature. After a period of time, the collector The outlet temperature of the collector drops again. When the outlet temperature of the collector drops below the preset temperature, the circulating water pump stops running, and the...

AI Technical Summary

Problems solved by technology

[0004] First of all, since the sun's radiation intensity changes all the time, and the water flow into the collector is constant, the water temperature at the outlet of the collector changes with the solar irradiance: when the solar irradiance is high At this time, the temperature at the outlet of the collector is high, but the water supply of the circulating water pump remains unchanged, so the outlet water temperature of the collector is too high, that is, the actual water temperature in the hot water storage tank is much higher than the preset value at the outlet of the collector. The temperature upper limit T(on); and when the solar irradiance decreases, the temperature at the outlet of the collector is low, and the water supply of the circulating water pump remains unchanged, so that the water temperature at the outlet of the collector may be lower than that at the outlet of the collector Pre-set temperature lower limit T(off), which reduces the heat collection efficiency of the collector

[0005] In addition, since the temperature at the outlet of the collector is always changing, the changing process is in a parabolic shape, which makes the circulating water pump start and stop too frequently, and the circulating water pump cannot work continuously, which affects its service life

At the same time, the intermittent operation of the circulating water pump reduces the heat collection efficiency of the entire solar water heating system

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