CN114543146A - Villages and small towns heating system based on phase change heat storage and multi-energy complementation - Google Patents

Abstract

The invention discloses a village and town heating system based on phase change heat storage and multi-energy complementation, which comprises a heat source side and a user side, wherein the heat source side comprises a solar heat collecting system, a middle-deep geothermal heat supply system, an electric heater and a phase change heat storage heat exchange box, the phase change heat storage heat exchange box is provided with two stages, the electric heater is arranged in the first stage, the solar heat collecting system is connected with the two stages of phase change heat storage heat exchange boxes to form a first heat storage loop and is connected with the second stage of phase change heat storage heat exchange box to form a second heat storage loop, a geothermal well of the middle-deep geothermal heat supply system is connected with the second stage of phase change heat storage heat exchange box to form a third heat storage loop, the two stages of phase change heat storage heat exchange boxes are connected with the user side to form a first heating loop, and the second stage of phase change heat storage heat exchange boxes is connected with the user side to form a second heating loop. The invention can meet the requirements that village and town residents adopt large temperature difference for heating at night and small temperature difference for heating in the daytime, and can ensure the continuity and stability of heating by adopting the complementation of two clean energy sources.

Description

A village heating system based on phase change heat storage and multi-energy complementation

technical field

The invention belongs to the technical field of heating, ventilation and air conditioning, and in particular relates to a village heating system based on phase-change heat storage and multi-energy complementation.

Background technique

The traditional heating system in villages and towns uses the flue gas generated by the stove for heating. Although it meets the heating needs of residents in winter to a certain extent, there are problems of poor continuous heating stability and environmental pollution. With the improvement of the indoor thermal environment requirements of village residents in winter and To protect the environment, it is imperative to make changes to the existing heating forms in villages and towns.

Due to the production and living habits of residents in villages and towns, people frequently enter and leave the room during the day, so the standard of clothing is that the outdoor activities will not feel cold in a short period of time. The results also show that most northern villagers believe that the temperature difference between indoor and outdoor should not be too large during the day in winter, which means that villagers and towns have different heating needs during the day and night. The existing heating system mostly adopts a constant temperature difference between the supply and return water to achieve stable heating. It is difficult to adapt to the actual needs of village residents for heating in winter.

As a clean and renewable energy, solar energy is widely distributed and has great potential for development and utilization. It is an excellent choice for heat sources in heating projects. However, a single solar energy system is greatly affected by the weather, and the energy supply is intermittent and unreliable. It cannot provide continuous and stable high-density energy at night and in rainy weather. When using it, it can be considered with other energy sources such as geothermal energy and thermal storage technology. combined use.

Energy storage technology can alleviate the mismatch between energy supply and demand in terms of time, space and intensity, while phase change energy storage technology refers to the use of phase change materials to absorb or release a large amount of latent heat in the process of changing the state of matter to achieve energy storage and release. , which greatly improves the energy storage density compared with sensible heat storage. The use of the phase change temperature control characteristics of the phase change material can also prolong the constant temperature time of heating, and the rational use of the phase change material can maintain the stability of the indoor temperature for a long time in the case of intermittent heating.

The Chinese patent with the patent number ZL202011005935.0 discloses a phase-change temperature-controlled kang suitable for heating in villages and towns in winter, including a kang plate, a metal bellows, and an electric heating wire. The metal bellows is filled with a phase-change material that has been melted at high temperature. The heated kang can basically maintain the constant temperature of the kang surface throughout the day by storing heat during cooking during the day, and the kang is heated by electric heating wires at night. Although the phase-change temperature-controlled heated kang makes good use of the phase-change heat storage technology, it is limited to heating during the day, and electric heating is used for heating at night when the demand is high, which is not economical. In addition, the end of the heated kang cannot bring a good thermal environment to the whole room, and with the rapid development of the countryside, the traditional bedding of the kang is being gradually replaced. Therefore, in the heating of villages and towns, phase change heat storage technology and new heating should be considered. end binding.

The Chinese patent with the patent number ZL201710830052.5 discloses a solar ground source heat pump combined energy supply system and its operation control method. The system mainly includes a solar heat collection system, a ground source heat pump system and a buried pipe system. By analyzing the domestic hot water demand, the user needs hot water supply time period, using solar energy and ground source heat pump to supply energy together; in the time period when domestic hot water supply is not required, the heat in the solar collector is used for soil heating. Although the system realizes the combined energy supply of solar energy and ground source heat pump, when the end users are relatively scattered, there is no law to follow in heat use, and it is difficult to achieve a balance between soil heat extraction and heat supplementation. In addition, the water tank is used to store heat, and the heat storage is small, and the solar energy cannot be fully utilized when the light conditions are good.

SUMMARY OF THE INVENTION

In order to solve the technical problems existing in the known technology, the present invention provides a village heating system based on phase-change heat storage and multi-energy complementation. It can not only ensure the continuity and stability of heating, but also will not pollute the environment.

The technical solution adopted by the present invention to solve the technical problems existing in the known technology is: a village heating system based on phase-change heat storage and multi-energy complementation, including two parts: a heat source side and a user side, and the heat source side includes solar energy A heat collection system, a mid-deep geothermal heating system, an electric heater, and a phase-change heat storage and heat exchange box. The phase-change heat storage and heat exchange box is provided with two stages. With the electric heater, the solar heat collection system is connected in series with the first-stage phase-change heat storage heat exchange box and the second-stage phase-change heat storage heat exchange box to form a first heat storage circuit, and the solar energy The heat collection system is connected with the second-stage phase-change heat storage heat exchange tank to form a second heat-storage circuit, and the mid-deep geothermal heating system is provided with a geothermal well, and the geothermal well is connected to the second-stage phase-change storage system. The heat exchange tanks are connected to form a third heat storage circuit, and the first-stage phase-change heat-storage heat-exchange tanks and the second-stage phase-change heat-storage heat exchange tanks connected in series are connected to the user side to form a first heating circuit, The second-stage phase-change heat storage and heat exchange tank is connected to the user side to form a second heating circuit; high temperature.

A heat exchange component is connected between the geothermal well and the second-stage phase-change heat storage heat exchange tank.

The heat exchange component is a primary heat exchange component, and the primary heat exchange component is a plate heat exchanger.

The heat exchange component further includes a secondary heat exchange component, and the secondary heat exchange component is a ground source heat pump unit.

The heating end on the user side adopts a floor heating structure, and the floor heating structure is provided with a structural layer, a thermal insulation layer, a heat storage layer and a leveling layer in sequence from bottom to top, and the heat storage layer is filled with phase change materials. A hot water coil is embedded in the phase change material of the heat storage layer, and the phase change temperature of the phase change material of the heat storage layer is higher than the phase change temperature of the phase change material filled in the second-stage phase change heat storage heat exchange tank. The variable temperature is lower and higher than the design temperature of the heating room.

The advantages and positive effects of the invention are as follows: the solar heat collection system and the middle-deep geothermal heating system are used as the main heat sources, which are used for heating the village and town residents in winter without polluting the environment; the phase change heat storage heat exchange box is used to use phase change materials Heat storage and heat release can alleviate the mismatch between energy supply and demand in terms of time and intensity; two-stage independent phase change heat storage and heat exchange boxes are used, and the phase change temperature of the phase change material in the two-stage phase change heat storage heat exchange box is adopted. Different, corresponding to the two-stage phase change heat storage heat exchange box, by designing different solar heat storage modes on the heat source side, complementing with geothermal energy, and using electric energy as auxiliary supplement at the same time, the continuity and stability of heating can be guaranteed. For the heating of the stage-change heat storage heat exchange box, different operating conditions are designed on the user side, and the temperature difference between the supply and return water at the end is changed through valve control, which can meet the different heating needs of village users in different periods of heating. Large temperature difference heating is used at night. , using small temperature difference heating during the day. To sum up, the present invention effectively utilizes solar energy and geothermal energy for heating in villages and towns on the basis of satisfying the heating needs of residents in different periods of time, and has good technical feasibility and broad application prospects.

Description of drawings

FIG. 1 is a schematic structural diagram of the present invention.

In the figure: 1. Solar water heater; 2. Geothermal well; 3. Plate heat exchanger; 4. Ground source heat pump unit; 5. Phase change heat storage and heat exchange box; 6. Electric heater; Heat storage and heat exchange tank; 8. Spiral pipe; 9. Second-stage phase change heat storage and heat exchange tank; 10. Water separator; 11. Water collector; 12. Leveling layer; 13. Hot water coil; 14. Heat storage layer; 15, insulation layer; 16, structural layer; P1~P5, circulating water pump; V1, combined valve; V2~V4, common valve; V5, confluence tee; V6, diverter tee.

Detailed ways

In order to further understand the content of the invention, features and effects of the present invention, the following embodiments are exemplified and described in detail with the accompanying drawings as follows:

Please refer to Figure 1, a village heating system based on phase change heat storage and multi-energy complementation, including two parts: the heat source side and the user side.

The heat source side includes a solar heat collection system, a mid-deep geothermal heating system, an electric heater 6 and a phase-change heat storage heat exchange box 5 .

The phase-change heat storage and heat exchange box 5 is provided with two stages, and the electric heater 6 is provided in the first-stage phase-change heat storage heat exchange box 7 .

The solar heat collection system is connected in series with the first-stage phase-change heat storage and heat exchange tank 7 and the second-stage phase-change heat storage heat exchange tank 9 in sequence to form a first heat storage circuit.

The solar heat collection system is connected with the second-stage phase-change heat storage heat exchange tank 9 to form a second heat storage circuit.

The middle-deep geothermal heating system is provided with a geothermal well 2, and the geothermal well 2 is connected with the second-stage phase-change heat storage and heat exchange tank 9 to form a third heat storage circuit.

The first-stage phase-change heat storage and heat exchange tank 7 and the second-stage phase-change heat storage heat exchange tank 9 are connected in series to the user side to form a first heating circuit.

The second-stage phase-change heat storage and heat exchange tank 9 is connected to the user side to form a second heating circuit.

The phase-change temperature of the first-stage phase-change heat storage and heat exchange tank is higher than that of the phase-change material filled in the second-stage phase-change heat storage and heat exchange tank.

The above system uses the solar heat collection system and the mid-deep geothermal heating system as the main heat sources to provide heat for the phase change heat storage and heat exchange box, and the user takes heat from the phase change heat storage heat exchange box. Heat and heat release, using solar energy and geothermal energy and other energy sources for heating in villages and towns.

In the above-mentioned first heating circuit, the first-stage phase-change heat storage and heat exchange tank 7 and the second-stage phase-change heat storage and heat exchange tank 9 are connected in series through a spiral tube 8 .

The heat collecting device of the solar heat collecting system adopts the solar water heater 1, which is more common in villages and towns. The solar water heater is equipped with a temperature sensor and a display interface. .

The effluent from the solar water heater flows into the phase change heat storage and heat exchange tank, where the heat is released to the phase change material in the heat storage heat exchange tank, and then returned to the solar water heater by the circulating pump for reheating. The heat storage tank is equipped with a corresponding valve on the pipeline. When the solar energy density is low, the effluent water can also be controlled to only enter the second-stage phase change heat storage and heat exchange tank.

The phase change heat storage heat exchange box 5 on the heat source side is provided with two-stage heat storage tanks, which are filled with phase change materials with different phase change temperatures respectively, so as to meet the heat storage of heat sources with different temperatures, effectively utilize low temperature heat sources, and meet the requirements for supply and return water on the user side. temperature difference requirements.

In this embodiment, in order to improve the heat exchange efficiency, a heat exchange component is connected between the geothermal well 2 and the second-stage phase change heat storage heat exchange tank 9 . More specifically, the heat exchange components may be provided with only primary heat exchange components, or may be provided with primary heat exchange components and secondary heat exchange components at the same time. In this embodiment, there are two heat exchange components, which are the primary heat exchange components- Plate heat exchanger 3 and secondary heat exchange component - ground source heat pump unit 4.

In this embodiment, the above-mentioned mid-deep geothermal heating system on the heat source side is mainly composed of a geothermal well 2, a plate heat exchanger 3, a ground source heat pump unit 4 and corresponding water pumps and valves. The secondary phase change heat storage heat exchange box stores heat. The process is as follows: the effluent water from the geothermal well first flows through the plate heat exchanger, and after one heat exchange in the heat exchanger, it flows into the ground source heat pump unit for cascade utilization to expand the utilization temperature difference of geothermal water, and then is pressurized and recharged by the circulating pump to ensure that the water is collected. Heat does not take water. The hot water obtained by the plate heat exchanger and the ground source heat pump unit flows into the second-stage phase change heat storage heat exchange box 9 after being combined by the three-way valve, and then releases heat to the phase change material and flows into the plate heat exchanger respectively through the split three-way With the heat pump unit, there are circulating pumps P3 and P4 at the return port of the plate heat exchanger and the heat pump unit to ensure the normal operation of the water system.

In order to save energy and realize intermittent heating, the heating terminal on the user side adopts a floor heating structure, and the floor heating structure is sequentially provided with a structural layer 16, a thermal insulation layer 15, a heat storage layer 14 and a leveling layer 12 from bottom to top. The layer 14 is filled with a phase change material, a hot water coil 13 is embedded in the heat storage layer 14, and the phase change temperature of the phase change material of the heat storage layer 14 is higher than that of the second-stage phase change. The phase change temperature of the phase change material filled in the heat storage heat exchange tank 9 is lower than the design temperature of the heating room. The heat storage layer at the heating end is different from the traditional radiant heating end. The heat storage layer is filled with phase change materials. Compared with the concrete sensible heat storage surface heat flow density, the phase change heat storage has less fluctuation and the heating time is long, which can be used in the daytime. Intermittent heating strategies are used when heating demand is low.

The above solar collector system has three operating modes:

1) When the solar radiation intensity is high, the hot water temperature is greater than the phase change temperature of the phase change material in the first-stage phase-change heat storage heat exchange box 7, close the valve V1, open the valve V2, and the hot water flows through the two-stage phase change in turn. After the heat is released from the variable heat storage heat exchange tank, it flows back to the solar water heater through the circulating pump P1.

2) When the solar radiation intensity is low, the temperature of the hot water is lower than the phase change temperature of the phase change material in the first-stage phase-change heat storage heat exchange tank 7, but higher than the phase change temperature in the second phase-change heat storage heat exchange tank 9 The phase change temperature of the material is changed. At this time, the valve V1 is opened and the valve V2 is closed, and the hot water directly enters the second phase change heat storage and heat exchange tank 9 for heat storage.

3) When in rainy weather, the hot water temperature is lower than the phase change temperature of the phase change material in the second phase change heat storage and heat exchange tank 9. At this time, temporarily close the valves V1, V2 and the water pump P1 and wait for the water temperature to rise.

For the mid-deep geothermal heating system, the effluent water from the geothermal well first flows through the plate heat exchanger 3, and then flows into the ground source heat pump unit 4 after heat exchange.

For the mid-deep geothermal heating system, the effluent from the user side of the plate heat exchanger and the effluent from the condensing side of the heat pump unit enter the second phase change heat storage and heat exchange tank 9 after passing through the confluence tee V5 for heat storage. The circulating water pumps P3 and P4 respectively flow back to the plate heat exchanger and the heat pump unit for reheating.

For the mid-deep geothermal heating system, if the solar hot water has met the heat storage requirements of the second phase change heat storage heat exchange tank 9, that is, the temperature in the second phase change heat storage heat exchange tank is already greater than the phase change temperature of its phase change material , there is no need to turn on the mid-deep geothermal heating system.

The electric heater 6 does not need to be turned on under normal circumstances, but the solar heat collection system cannot meet the temperature requirements of the first-stage phase change heat storage heat exchange box 7, that is, the temperature in the phase change heat storage heat exchange box 7 is lower than its phase change The phase transition temperature of the material, and there is a heating demand at night, that is, when the temperature of the heat storage layer 14 is lower than the phase transition temperature of its phase change material, the electric heater 6 is turned on for auxiliary heating.

The above-mentioned user-side heating can be divided into three operating conditions:

1) In the night heating condition, open the valve V3 and close the valve V4, and the return water on the user side flows into the second phase change heat storage and heat exchange tank and the first phase change heat storage heat exchange tank through the water collector 11 and the circulating water pump P5 in turn. After heating, it flows into the radiant end through the water separator 10 for heating. When heating at night, the return water of the water collector flows through the second-stage phase change heat storage heat exchange box and the first-stage phase change heat storage heat exchange box for heating, and then used for user heating. In this form, the temperature difference between the supply and return water is large. , suitable for terminal water supply when the night load is large and the heating demand temperature is high.

2) In the daytime heating condition, close the valve V3 and open the valve V4. After passing through the water collector 11 and the circulating water pump P5, the user-side return water only flows into the second phase-change heat storage and heat exchange tank and then flows into the water separator 10 after being heated. Radiation end, the implementation of small temperature difference heating. During the daytime heating, the return water of the water collector only flows through the second phase change heat storage heat exchange box for heating, and then is used for user heating. In this form, the temperature difference between the supply and return water is small, which is suitable for the daytime load is small and the heating demand temperature is higher. Terminal water supply when low.

3) In intermittent heating conditions, due to the existence of the phase change material filling layer 14, the heating time at the radiation end is extended. When the load is small during the day and the temperature of the heat storage layer is greater than the phase change temperature of the phase change material in the filling layer, the cycle can be closed. Pump P5, stop heating, and run as energy-saving as possible on the premise of meeting the thermal comfort requirements of residents.

The inlet water to the water separator on the user side of the system comes from the phase change heat storage heat exchange box, the effluent water enters the user terminal for heating, and the user side return water enters the phase change heat storage heat exchange box through the water collector for reheating. A circulating water pump P5 is set between the heat exchange boxes to meet the normal operation of the user-side water system.

On the user side of the system, based on two-stage heat storage tanks with different phase transition temperatures, three water supply and return conditions are set to meet the different heating needs of village residents during the day and night, as well as intermittent heating needs.

The following takes a specific operating condition as an example to describe the operation mode of the system in detail. For example, in the first-stage phase-change heat storage heat exchange box 7, a phase-change material with a phase-change temperature of 50°C is selected, and the second phase-change heat storage A phase change material with a phase change temperature of 40°C is selected in the heat exchange box 9 , and a phase change material with a phase change temperature of 29°C is selected in the heat storage layer 14 . The water temperature of the geothermal well is 50°C, and the temperature drops to 42°C after one heat exchange by the plate heat exchanger, and then the temperature drops to 30°C after the heat is taken by the heat pump unit. The operating conditions of the user side of the heat exchanger and the condensing side of the heat pump unit are both 45°C/40°C.

Based on the above working conditions, when the water temperature in the solar water heater is greater than 50°C, the solar hot water will store heat in the two-stage phase change heat storage and heat exchange tank in turn. When the water temperature in the solar water heater is lower than 40°C, the circulating water pump P3 will be stopped and the solar energy heat storage.

Based on the above working conditions, when the temperature in the second phase change heat storage heat exchange box is less than 40°C and the solar energy cannot meet the heat storage demand, the middle and deep geothermal heating is turned on, and the water temperature of the geothermal well is 50°C. After heat exchange, the temperature drops to 42°C, and then the temperature drops to 30°C after the heat is taken by the heat pump unit. The effluent water of the user side of the heat exchanger and the condensation side of the heat pump unit is both 45°C, and the water is cooled to 40°C after the heat is released in the second phase change heat storage and heat exchange box 9 for cyclic operation.

Based on the above working conditions, the return water at the end of the heating can be designed to be 35°C. During daytime heating, the return water at the end is heated to 40°C by the second phase change heat storage heat exchange box for water supply. The temperature difference between the supply and return water is 5°C, and the indoor design temperature When heating at night, the end return water is heated to 40°C by the second phase change heat storage and heat exchange box, and then enters the first phase change heat storage heat exchange box to be heated to 45°C for water supply, and 10°C is used for the return water. The water temperature difference, the indoor design temperature is 18 ℃.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments. Under the inspiration of the present invention, personnel can also make many forms without departing from the scope of the present invention and the protection scope of the claims, which all belong to the protection scope of the present invention.

Claims (5)

1. A heating system for villages and small towns based on phase change heat storage and multi-energy complementation is characterized by comprising a heat source side and a user side,

the heat source side comprises a solar heat collecting system, a middle-deep geothermal heat supply system, an electric heater and a phase-change heat storage heat exchange box,

the phase-change heat storage and exchange box is provided with two stages,

the electric heater is arranged in the first-stage phase-change heat storage heat exchange box,

the solar heat collecting system is sequentially connected with the first-stage phase-change heat storage and exchange box and the second-stage phase-change heat storage and exchange box in series to form a first heat storage loop,

the solar heat collection system is connected with the second-stage phase-change heat storage heat exchange box to form a second heat storage loop,

the medium-deep geothermal heating system is provided with a geothermal well, the geothermal well is connected with the second-stage phase-change heat storage heat exchange box to form a third heat storage loop,

the first-stage phase-change heat storage heat exchange box and the second-stage phase-change heat storage heat exchange box which are connected in series are connected with a user side to form a first heating loop,

the second-stage phase-change heat storage heat exchange box is connected with a user side to form a second heating loop;

the phase-change temperature of the phase-change material filled in the first-stage phase-change heat storage heat exchange box is higher than that of the phase-change material filled in the second-stage phase-change heat storage heat exchange box.

2. The village and town heating system based on phase change heat storage and multi-energy complementation of claim 1, wherein a heat exchange component is connected between the geothermal well and the second-stage phase change heat storage heat exchange tank.

3. The village and town heating system based on phase change heat storage and multi-energy complementation of claim 2, wherein said heat exchange component is a primary heat exchange component, and said primary heat exchange component is a plate heat exchanger.

4. The village and town heating system based on phase change heat storage and multi-energy complementation of claim 3, wherein the heat exchange component further comprises a secondary heat exchange component, and the secondary heat exchange component is a ground source heat pump unit.

5. The village and town heating system based on phase-change heat storage and multi-energy complementation of claim 1, wherein the heating end of the user side adopts a floor heating structure, the floor heating structure is sequentially provided with a structural layer, a heat preservation layer, a heat storage layer and a leveling layer from bottom to top, the heat storage layer is filled with a phase-change material, a hot water coil is embedded in the phase-change material of the heat storage layer, and the phase-change temperature of the phase-change material of the heat storage layer is lower than that of the phase-change material filled in the second-stage phase-change heat storage heat exchange box and higher than the indoor design temperature of heating.

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