A control method for a double-tank solar water heating system with varying minimum water levels

Abstract

The invention discloses a control method for a lowest-water-level-changing double-water-tank solar water heating system. The control method includes the following steps that multiple parameters of the double-water-tank solar water heating system in all time periods in n days before a forecasting day are collected; calculation is conducted to obtain the water use amounts of all the time periods in the n days before the forecasting day by subtracting the water flow of a water return main pipe in the corresponding time periods from the water flow of a water supply main pipe of all the time periods in the n days before the forecasting day; with the combination of a statistical method of t distribution in applied mathematical statistics and under the set confidence coefficient, the following formulas are adopted for calculating the forecasting values of the water use amounts of all the time periods in the forecasting day; the water level set value of a gradient temperature control heat supply water tank in the forecasting day is calculated; heat collection circulation is conducted; a heat collection water tank supplements water to the heat supply water tank; water supplementation of the heat collection water tank is conducted; the heat collection water tank supplements water to the heat supply water tank; and gradient temperature control water supplementation and overheat protection are conducted. By the adoption of the method, the starting time of an auxiliary heat source is shortened, and it is expected that the energy is saved by 20% or higher than that of a single-water-tank solar water heating system.

Description

technical field [0001] The invention relates to a control method of a double water tank solar water heating system, in particular to a control method of a double water tank solar water heating system with variable minimum water levels. Background technique [0002] At present, the country is vigorously developing the utilization of renewable energy, and the solar water heating system is one of the most commonly used methods in solar energy utilization. However, the amount of solar radiation varies with seasons, day and night, and is also strongly affected by random factors such as weather changes. The hot water system is equipped with an auxiliary heat source, and the energy consumption of the auxiliary heat source has become the main energy consumption of the solar water heating system. How to minimize the opening time of the auxiliary heat source while meeting the water demand of users is to reduce the energy consumption of the solar water heating system main direction. ...

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Problems solved by technology

[0004] The operation principle of this kind of system is simple, and the control is convenient, but usually in order to ensure the higher water consumption requirements in summer, the minimum water level set in the water tank is much higher than the actual hourly water consumption, and the parameter setting value is a fixed value, It cannot change with the seasons and users' water habits, and the setting of parameters lacks scientificity and accuracy. The minimum water level of the system is the main factor affecting the heating time of the system's auxiliary heat source, which directly affects the energy consumption of the system. Due to seasons, weather and water consumption Uncertain factors such as the water volume in the water tank are much larger than the actual water volume at most of the time. In order to ensure the water temperature of a large amount of hot water in the water tank, the heating time of the auxiliary heat source is significantly increased, which increases the energy consumption of the system.

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