CN111981554A - Solar energy and phase change energy storage-based heat storage and supply system and control method - Google Patents

Abstract

The invention discloses a heat storage and heating system and a control method based on solar energy and phase-change energy storage. The solar energy and peak-to-valley electrical energy can be stored and reasonably controlled by utilizing the characteristics of phase change energy storage materials with high latent heat, and by utilizing the characteristics of phase change materials with constant phase transition temperature, only by controlling the outlet temperature of the solar collector, The monitoring of the outlet temperature of the water tank and the outlet temperature of the phase change energy storage tank, as well as the control of the relevant valves, can obtain a continuous and stable hot water supply with a constant temperature. The system contains only one circulating pump, and can reasonably store and utilize solar energy and peak-valley electric energy, so it has the characteristics of low energy consumption and energy saving. At the same time, since only four valves are involved in the operation, the operation is simple and easy to automate.

Description

A heat storage and heating system based on solar energy and phase change energy storage and its control method

technical field

The invention belongs to the technical field of new energy and energy saving, and in particular relates to a storage and heating system and a control method based on solar energy and phase change energy storage.

Background technique

my country has abundant solar energy resources. As a clean and renewable energy, it has received extensive attention in heating and other aspects. However, solar energy has inhomogeneity and intermittency in time and space, and there is a mismatch between its energy distribution and heating and heating. In order to continuously and effectively provide heating and heat, the application of thermal storage technology is particularly important.

Thermal energy storage can be divided into sensible heat storage and latent heat storage. In practical engineering applications, the solar heating system mainly uses water as the heat storage medium for sensible heat storage. Due to the limitation of its energy storage density, it is often necessary to equip a large-capacity hot water storage tank, and the heating temperature varies. stability issues. Latent heat storage utilizes the phase change of phase change materials to store heat, and phase change materials are able to release/absorb a large amount of latent heat during the phase change process, while maintaining the temperature constant or changing within a small temperature range during the phase change process. Therefore, the rational utilization of solar energy by using phase change materials can not only solve the problem of space-time matching between solar energy and heating and heating, but also improve the energy storage density and effectively control the heating and heating temperature.

CN209944492U discloses a small rural heating system based on solar heat absorption, phase change heat storage and electric auxiliary heat, but the water body to be heated in the system is directly connected to the solar heat collector for heating, which is easy to cause freezing and blockage of pipelines at night in winter question. In addition, the system places the phase change material directly in the tank body, and the hot water from the collector simultaneously heats the water and the phase change material in the water tank. Due to the large latent heat of the phase change material, the water temperature in the water tank changes slowly, that is, the temperature response is not sensitive enough. CN209978160U discloses a floor heating heating and hot water supply system based on phase-change heat storage, which also has the same problem of water freezing and clogging of pipes as in CN209944492U. At the same time, the structure and control of the system are extremely complicated. For example, 2 pumps and 11 solenoid valves need to be controlled. CN210107532U discloses an intelligent phase-change heating system, however, the system directly connects the solar collector, the phase-change heat storage and the water load (such as spray water supply, radiator) in series, so it cannot effectively control and control the solar energy. Effectively adjust the water temperature. CN208222845U discloses a heating system based on solar energy, high temperature phase change heat storage and electric auxiliary multi-energy complementary heating. Although the system uses heat transfer oil as the heat transfer medium after solar heat collection, the freezing problem of the water medium is avoided, but the system will There are many problems when the phase change material is placed in a high temperature heat storage tank. For example, when the solar thermal collector stops working at night and the phase change material starts to emit heat, the heat transfer oil still needs to pass through the solar thermal collector, resulting in a partial heat loss. In addition, the system only contains two pumps in the oil circuit system, so the operation energy consumption is high.

At present, the heating and storage systems based on solar energy and phase change energy storage generally have certain problems, such as operation and maintenance problems caused by the complexity of the system structure, energy consumption problems caused by the large number of pumps, and pipeline problems caused by unreasonable system design. Road freezing, unstable heating temperature, insufficient solar energy utilization and other problems. In view of this, it is of great significance to develop a storage and heating system with simple system structure and operation, low operating cost, stable heating supply and small temperature change for realizing energy conservation and environmental protection, and improving people's living standards.

SUMMARY OF THE INVENTION

The purpose of the present invention is to develop a low-cost storage device based on solar energy and phase-change energy storage, which is anti-freezing, simple in structure and operation, and only needs one pump to operate, aiming at the contradiction between solar energy and heating in time and space. Heating system.

The technical scheme provided by the present invention is as follows:

A storage and heating system based on solar energy and phase-change energy storage, comprising: a solar collector (1), a phase-change energy storage tank (2), a water tank (3), a pump (4), valves (5, 6, 7, 8), auxiliary heater (9), temperature sensor (10, 11, 12) and water tank heat exchanger (13). The outlet of the solar collector (1) is connected with the valve (5), and the inlet of the solar collector (1) is respectively connected with the outlet of the water tank heat exchanger (13) and the outlet of the phase change energy storage tank (2) through a three-way pipe. The low temperature interface is connected; the high temperature interface of the phase change energy storage tank (2) is connected with the valves (6) and (7) respectively through the three-way pipe; the inlet of the water tank heat exchanger (13) is connected with the valve (8); the pump (4) The inlet of the pump (4) is respectively connected with the valves (5) and (6) through the three-way pipe, and the outlet of the pump (4) is respectively connected with the valves (7) and (8) through the three-way pipe.

Moreover, the phase-change energy storage tank (2) is filled with a phase-change energy storage material with a phase-change temperature of 30-90° C., and auxiliary heating is provided in the phase-change energy storage tank (2) and the water tank (3) individually or simultaneously device.

Moreover, temperature sensors are respectively provided at the outlet of the solar heat collector (1), the high temperature interface of the phase change energy storage tank (2) and the water tank (3).

Moreover, water or heat-conducting oil, preferably anti-freezing heat-conducting oil, is passed into the pipes connecting each part of the system.

Moreover, the water tank heat exchanger (13) is placed inside the water tank (3), and the water tank (3) is provided with a cold water inlet (14) and a hot water outlet (15).

During the operation of the system, the valves (5, 6, 7, 8) are opened and closed according to the feedback temperature of the temperature sensors (10, 11, 12). When the solar energy is excessive, the energy is stored and released by the phase-change energy storage tank (2); when the solar energy is insufficient, the auxiliary heater (9) is used to supplement the energy.

The advantages and positive effects of the present invention are: the system only contains one pump, and only needs to control four valves during operation, so the system structure and operation are simple and the operation cost is low. In addition, the system can make full use of solar energy and peak-to-valley electric energy, and automatically obtain a stable outlet water temperature through the control of the phase change temperature of the phase change material.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the accompanying drawings:

Fig. 1 is the structure schematic diagram of the storage heating system in embodiment 1;

Fig. 2 is the use state diagram (state 1) of the storage and heating system in the embodiment 1;

Fig. 3 is the use state diagram (state 2) of the storage and heating system in the embodiment 1;

Fig. 4 is the use state diagram (state 3) of the heating storage and heating system in the embodiment 1;

Fig. 5 is the use state diagram (state 4) of the heating storage and heating system in the embodiment 1;

In the figure: 1. Solar collector; 2. Phase change energy storage tank; 3. Water tank; 4. Pump; 5-8. Valve; 9. Auxiliary heater; 10-12. Temperature sensor; 14. Cold water inlet; 15. Hot water outlet.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments. The specific embodiments are only used to further illustrate the present invention in detail, and do not limit the protection scope of the claims of the present application.

Example 1:

A heat storage and heating system based on solar energy and phase change energy storage, as shown in Figure 1, includes: a solar collector 1, a phase change energy storage tank 2, a water tank 3, a pump 4, valves 5, 6, 7, 8 , auxiliary heater 9 , temperature sensors 10 , 11 , 12 and water tank heat exchanger 13 . The outlet of the solar collector 1 is connected to the valve 5, and the inlet of the solar collector 1 is respectively connected to the outlet of the water tank heat exchanger 13 and the low temperature interface of the phase change energy storage tank 2 through a tee pipe; the phase change energy storage tank 2 The high temperature interface is connected with valves 6 and 7 through tee pipes; the inlet of water tank heat exchanger 13 is connected with valve 8; the inlet of pump 4 is connected with valves 5 and 6 through tee pipes, and the outlet of pump 4 is connected with valves 5 and 6 through tee pipes. The tubes are connected to valves 7 and 8, respectively.

The phase change energy storage tank 2 is filled with a phase change energy storage material with a phase change temperature of 55° C., and an auxiliary heater is arranged in the phase change energy storage tank 2 .

At the outlet of the solar collector 1, the high temperature interface of the phase change energy storage tank 2 and the water tank 3 are respectively provided with temperature sensors.

Pass the heat transfer oil into the pipes connecting each part of the system.

The water tank heat exchanger 13 is placed inside the water tank 3 , and the water tank 3 is provided with a cold water inlet 14 and a hot water outlet 15 .

According to different weather conditions or day and night differences, the system includes four working states.

State 1 (Fig. 2): When the weather conditions are good during the day, the outlet temperature T1 of the solar collector ₁ is ≥55°C, while the temperature T3 in the water tank ₃ is ≤55°C, open the valves 5 and 8, and close the valves 6 and 7 At this time, under the action of the pump 4, the heat collected by the solar collector 1 is transferred to the water tank 3 through the heat transfer oil, and the water in the water tank is heated by the heat exchanger 13.

State 2 (Fig. 3): When the weather conditions are good during the day, the outlet temperature T1 of the solar collector ₁ is ≥55°C, and the temperature T3 in the water tank ₃ is ≥55°C, open the valves 5 and 7, and close the valves 6 and 8 At this time, under the action of the pump 4, the heat collected by the solar collector 1 is transferred to the phase-change energy storage tank 2 through the heat-conducting oil, and the remaining solar energy is stored in the phase-change energy storage material.

State 3 (Figure 4): When the weather conditions are poor at night or during the day, the outlet temperature T ₁ of the solar collector 1 is <55°C, the outlet temperature T ₂ of the phase change energy storage tank 2 is ≥55° C, and the temperature T in the water tank 3 ₃ When <55℃, open valves 6 and 8 and close valves 5 and 7. At this time, under the action of pump 4, the heat stored in the phase change energy storage tank 2 is transferred to the water tank 3 through the heat transfer oil, and passes through the heat exchanger. 13 Heat the water in the tank.

State 4 (Fig. 5): When the weather conditions are poor at night or during the day, the outlet temperature of the solar collector 1 is T ₁ <55°C, the outlet temperature of the phase change energy storage tank 2 is T ₂ <55° C, and the temperature in the water tank 3 is T ₃ When <55℃, turn on the auxiliary heater 9, open the valves 6 and 8, close the valves 5 and 7, at this time, the phase change energy storage material is heated under the action of the auxiliary heater 9, and under the action of the pump 4, the heat The heat transfer oil is transferred to the water tank 3 and the water in the water tank is heated by the heat exchanger 13 .

When the outlet temperature T ₂ of the phase-change energy storage tank 2 is greater than or equal to 55° C., the auxiliary heater 9 is stopped, and the system returns to state 3 ( FIG. 4 ) at this time.

The embodiments of the present invention shown and described above, or the technical solutions of the accompanying drawings, all embody the advantages of the present invention and the simple and convenient storage and supply of thermal energy, as well as automatic adjustment of water temperature. It should be understood that the detailed description of the technical method of the present invention by the preferred embodiment is illustrative and not restrictive, and those skilled in the art can make improvements or transformations according to the above description on the basis of reading the description of the present invention. The valve is a solenoid valve and controlled by a controller, or the water tank is modified to provide heating water and domestic water at the same time. All these improvements and changes should belong to the protection scope of the appended claims of the present invention.

Claims (10)

1. A storage and heating system based on solar energy and phase-change energy storage, characterized in that: comprising a solar collector (1), a phase-change energy storage tank (2), a water tank (3), a pump (4), a valve (5, 6, 7, 8), the outlet of the solar collector (1) is connected to the valve (5), and the inlet of the solar collector (1) is respectively connected to the outlet of the water tank heat exchanger (13) and the phase change storage The low temperature interface of the energy box (2) is connected to the high temperature interface of the phase change energy storage box (2) respectively with the valves (6) and (7) through the three-way pipe; the inlet of the water tank heat exchanger (13) is connected to the valve (8) ) is connected; the inlet of the pump (4) is connected with the valves (5) and (6) respectively through the tee pipe, and the outlet of the pump (4) is respectively connected with the valves (7) and (8) through the tee pipe. 2 . The system according to claim 1 , wherein the phase change energy storage tank ( 2 ) is filled with phase change energy storage materials with a phase change temperature of 30-90° C. 3 . 3. The system according to claim 1, characterized in that: an auxiliary heater is provided in the phase-change energy storage tank (2) and/or the water tank (3). 4. The system according to claim 1, characterized in that: temperature sensors are respectively provided at the outlet of the solar collector (1), the high temperature interface of the phase change energy storage tank (2) and the water tank (3). 5. The system according to claim 1, characterized in that: water or heat-conducting oil is passed through the pipes connecting each part of the system. 6. The system according to claim 1, characterized in that: the water tank heat exchanger (13) is placed inside the water tank (3), and the water tank (3) is provided with a cold water inlet (14) and a hot water outlet (15). 7. The system control method according to claim 1, characterized in that: when the outlet temperature of the solar collector (1) is higher than the phase change temperature of the phase change material in the phase change energy storage tank (2), and the water tank When the temperature in (3) is lower than the phase change temperature of the phase change material, open the valves (5) and (8), and close the valves (6) and (7). At this time, under the action of the pump (4), the solar energy collects heat The heat collected by the device (1) is transferred to the water tank (3) through the heat conduction medium in the pipeline, and the water in the water tank is heated by the heat exchanger (13). 8. The control method of the system according to claim 1, characterized in that: when the outlet temperature of the solar collector (1) and the temperature in the water tank (3) are both higher than the phase change temperature of the phase change material, the valve is opened (5) and (7), close the valves (6) and (8). At this time, under the action of the pump (4), the heat collected by the solar collector (1) is transferred to the phase change storage device through the heat transfer medium in the pipeline. in the energy box (2), and the remaining solar energy is stored in the phase change energy storage material. 9. The system control method according to claim 1, characterized in that: when the outlet temperature of the solar collector (1) and the temperature in the water tank (3) are both lower than the phase change temperature of the phase change material, the phase change storage When the temperature of the high temperature interface of the energy box (2) is higher than the phase change temperature of the phase change material, open the valves (6) and (8), and close the valves (5) and (7). At this time, under the action of the pump (4) , the heat stored in the phase change energy storage tank (2) is transferred to the water tank (3) through the heat conduction medium in the pipeline, and the water in the water tank is heated by the heat exchanger (13). 10. The system control method according to claim 3, characterized in that: when the outlet temperature of the solar collector (1), the high temperature interface temperature of the phase-change energy storage tank (2) and the temperature in the water tank (3) are all the same When it is less than the phase change temperature of the phase change material, turn on the auxiliary heater (9), open the valves (6) and (8), and close the valves (5) and (7). At this time, under the action of the auxiliary heater (9) The phase change energy storage material is heated, and under the action of the pump (4), the heat is transferred to the water tank (3) through the heat conduction medium in the pipeline, and the water in the water tank is heated by the heat exchanger (13); When the temperature of the high temperature interface of the energy box (2) is higher than the phase change temperature of the phase change material, the auxiliary heater (9) is stopped.

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