Vacuum tube solar water heater achieving convection heat exchange and control method of vacuum tube solar water heater

Abstract

The invention relates to a vacuum tube solar water heater achieving convection heat exchange and a control method of the vacuum tube solar water heater. The vacuum tube solar water heater comprises awater box and multiple vacuum tubes communicating with the water box. The water box comprises a box body, a water inlet tube arranged on one side of the box body and a water outlet tube arranged on the other side of the box body, and one end of the water inlet tube is connected with a circulating assembly. Obliquely-arranged flow guide plates are arranged in the vacuum tubes, each vacuum tube is divided by the corresponding flow guide plate into a cold water bin and a hot water bin, the lower end of each flow guide plate smoothly extends towards the corresponding hot water bin to be provided with a flow guide portion, multiple fins are arranged between the side end of each flow guide plate and the inner wall of a metal inner tube and are distributed from top to bottom, openings of the finsin the hot water bins are arranged by facing the open ends of the vacuum tubes, and spiral faces are arranged at the bottoms of the inner walls of the metal inner tubes. The vacuum tube solar water heater has the following advantages that the vacuum tubes of special structures are adopted, rotational flow is formed when water passes through the vacuum tubes to achieve heat transfer, the contact faces with the vacuum tubes are improved, the heat transfer efficiency of the vacuum tubes is improved, and through additional mounting of the circulating assembly, the convection heat exchange efficiency in the water box is improved.

Description

Technical field: [0001] The invention belongs to the field of solar heat collectors, and in particular relates to a convective heat exchange vacuum tube solar water heater and a control method thereof. Background technique: [0002] Solar energy is a distributed and intermittent energy source. To make full use of it, energy storage technology is needed to store sufficient solar energy during the day for use at night or on cloudy days. A solar collector is a device that absorbs solar radiation energy and converts solar radiation into other forms of energy by absorbing solar radiation of a certain wavelength. At present, the vacuum tube structure used for solar collectors adopts double-layer glass tubes. One end is open and the other end is a long cylindrical pipe in a closed state. The closed end is placed downwards, and the open end is connected to the header of the solar collector. The double-layer glass tube The air interlayer between is vacuum treated to reduce heat loss...

AI Technical Summary

Problems solved by technology

[0003] In the existing vacuum tube solar water heater, the cold water in the water tank is larger than the hot water in the vacuum tube. After the water passes through the vacuum tube, the temperature rises and the density decreases, so the hot water in the vacuum tube moves to the water tank, while the water in the water tank The cold water moves to the vacuum tube. In the area where the vacuum tube is connected to the water tank, there are jets of hot fluid, inflow of cold fluid, and mixed flow of hot and cold fluid. There is a phenomenon of temperature stratification at the bottom of the water tank, and the average temperature of the water tank is low. To solve this problem, people came up with Technical scheme of setting deflector in vacuum tube

[0004] For example, in the patent No. 201110153073.0 vacuum tube diversion and circulation device, a diversion cover is installed at the end of the double-layer glass vacuum tube, and a header box is installed outside the diversion cover. Separated into cold water channel and hot water channel, this structure has the following defects: 1. The flow space of the water flow at the port of the vacuum tube is small, so that the convective heat transfer effect of the entire water tank is still not ideal; 2. The upper end of the partition passes through the guide cover and The vacuum tube is fixed, and the lower end of the partition extends into the vacuum tube. When the water flow circulates and exchanges heat in the vacuum tube, it will have a certain impact on the partition. Falling off into the vacuum tube will also cause impact damage to the vacuum tube; 3. The bottom of the vacuum tube has poor fluidity, and the bottom of the vacuum tube is prone to bursting due to thermal stress

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