A concentrating solar seasonal sand high-temperature heat storage heating and hot water system

Abstract

The present invention relates to a concentrating solar seasonal sand high-temperature heat storage heating and hot water system, which includes a low-temperature sand storage tank, a high-temperature sand storage tank in winter, a high-temperature sand storage tank in summer, a sand heater, a tower heliostat, a first and a second heat exchanger and their pipeline systems. The low-temperature sand storage tank is placed on the top side, and the high-temperature sand storage tank in summer is placed on the bottom side. The two are respectively connected to the high-temperature sand storage tank in winter through the sand heater and pipelines; the high-temperature sand storage tank is connected to the low-temperature sand storage tank through a variable-frequency sand pump to form a circulation loop; the tower heliostat is placed around the high-temperature sand storage tank; the heat transfer oil ends of the first and the second heat exchanger and their pipeline systems exchange heat with the sand in the inner cavity of the high-temperature sand storage tank, and the water ends are respectively connected to the building heating equipment and the building hot water pipeline to form a circulation loop. The present invention supplies building hot water in the non-heating season and is used for building heating in the heating season, realizing the seasonal use of solar energy.

Description

Technical Field

[0001] This invention patent relates to a concentrating solar seasonal heating and hot water system, and particularly to a concentrating solar seasonal heating and hot water system integrated with the function of high-temperature heat storage in sand. Background Technique

[0002] At present, building energy consumption in China accounts for about 30-40% of the total social energy consumption and is expected to continue to increase. Among them, heating that mainly uses fossil fuels and electricity is an important part of building energy consumption in winter. To slow down climate change and reduce the use of fossil fuels, renewable energy technologies have developed rapidly in recent years. However, many of these technologies have scheduling problems such as intermittency and unpredictability. Therefore, the application of large-scale renewable energy technologies is closely related to energy storage to improve their dispatchability.

[0003] In terms of thermal energy, one of the most commonly used technologies is sensible heat energy storage, including solid material heat storage and packed bed heat storage. The development and research of both aim to find suitable storage materials and efficient systems, and the price of the storage materials themselves is the main part of the investment cost. Storing heat in solid particles is a commonly used method for thermal energy storage, which allows the storage and distribution of thermal energy from ambient temperature to over 1000°C. Currently, common storage materials include molten salts, phase change materials, etc. Molten salts have a relatively high freezing temperature and are prone to decomposition at high temperatures, so they cannot achieve high-temperature heat storage; although phase change materials have a relatively high heat storage density and can exchange heat within a relatively narrow range, their cost is high and they are not suitable for application in large-scale thermal energy storage systems. Sand, on the other hand, has a low cost, a high melting point, good heat capacity values, can achieve high-temperature heat storage and is easily obtained. It can be obtained from local natural resources, thus eliminating the cost of this part of imported materials and requiring almost no pretreatment. Utilizing the characteristics of high-temperature heat storage in sand, a concentrating solar seasonal high-temperature sand heat storage heating and hot water system is proposed, which can store and use solar energy through sand as the heat storage medium.

[0004] Through a literature search of the prior art, it is found that for the Chinese patent application No. 201821498926.8, the utility model name is: Sand Heat Storage Filling Machine. This technology discloses a sand heat storage filling machine that uses off-peak electricity to store heat in sand and releases heat during peak electricity consumption for winter heating. Inside the device, there is a sealed cavity filled with sand. Inside the cavity, multiple high-temperature resistant seamless steel pipes are evenly arranged. Inside the steel pipes, there are heating pipes. The two ends of the electric heating wires in the heating pipes are connected to the power supply. During the low electricity consumption period, the power supply is turned on to store heat in the sand bed. During the peak electricity consumption period, the sand exchanges heat with the heat transfer oil in the heat transfer oil pipes evenly arranged in the cavity, and the released heat is used for building winter heating. However, this device has a complex structure, requires external electrical energy supply for heat storage, does not directly utilize renewable energy such as solar energy, and has limited application scenarios. It can be seen that for the above-mentioned sand heat storage filling machine that uses off-peak electricity for heat storage, although it can reduce costs and usage costs, there are problems such as a complex structure, high energy consumption for electric heat storage, and insufficient energy conservation. The concentrating solar seasonal sand high-temperature heat storage heating and hot water system proposed in the present invention can store the solar energy collected in summer in sand, supply building hot water during the non-heating season, and then release this energy through a heat exchanger during the heating season for building heating. Its structure is simple, easy to install, does not require external energy supply, and can achieve a high degree of building energy conservation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a concentrating solar seasonal sand high-temperature heat storage heating and hot water system that collects solar energy and stores it in sand during the non-heating season, and partially uses it to supply building hot water; and releases this energy through a heat exchanger during the heating season to achieve the purpose of building heating.

[0006] The present invention is realized through the following technical solutions. The present invention relates to a concentrating solar seasonal sand high-temperature heat storage heating and hot water system, which includes: a low-temperature sand storage tank, a winter high-temperature sand storage tank, a summer high-temperature sand storage tank, a first heat exchanger and its pipeline system, a second heat exchanger and its pipeline system, a sand heater, and a tower heliostat.

[0007] The lower part of the low-temperature sand storage tank is funnel-shaped and is placed above the winter high-temperature sand storage tank, and the two are connected by the sand heater; the lower part of the winter high-temperature sand storage tank is funnel-shaped and is placed above the summer high-temperature sand storage tank, and the two are connected by a pipeline. The outer sides of both are provided with adiabatic insulation layers with low heat conductivity, such as polyurethane, glass wool, rubber and plastic, etc., and valves are provided at the pipeline. The winter high-temperature sand storage tank and the summer high-temperature sand storage tank are respectively connected to a variable-frequency sand pump through pipelines, and a pipeline connection between the variable-frequency sand pump and the low-temperature sand storage tank forms a circulation loop.

[0008] The described first heat exchanger and its pipeline system include a first heat exchanger, a circulation pipeline, and a first heat transfer oil heat exchange tube, which are used for heat exchange between sand and heat transfer oil, and between heat transfer oil and water; it has a heat transfer oil end and a water end. The heat transfer oil at the heat transfer oil end exchanges heat with the sand in the inner cavity of the winter high-temperature sand storage tank at the first heat transfer oil heat exchange tube through a circulation pump and a circulation pipeline and forms a circulation loop. The water end is connected to a building heating device through a circulation pump and a circulation pipeline and forms a circulation loop.

[0009] The described second heat exchanger and its pipeline system include a second heat exchanger, a circulation pipeline, and a second heat transfer oil heat exchange tube, which are used for heat exchange between sand and heat transfer oil, and between heat transfer oil and water; it has a heat transfer oil end and a water end. The heat transfer oil at the heat transfer oil end exchanges heat with the sand in the inner cavity of the summer high-temperature sand storage tank at the second heat transfer oil heat exchange tube through a circulation pump and a circulation pipeline and forms a circulation loop. The water end is connected to a building hot water pipeline through a circulation pump and a circulation pipeline and forms a circulation loop.

[0010] The described tower-type heliostat is composed of a tracking controller, a mechanical support structure, and a reflector, which is arranged around the high-temperature sand storage tank, and always maintains an optimal angle with the sun, so as to collect solar energy with the highest efficiency and reflect the sun's rays to the described sand heater, which can heat the sand in the sand heater to 800 °C.

[0011] The described sand heater is located at the focus of the described tower-type heliostat, and an electric valve is provided near the low-temperature sand storage tank, and a temperature sensor is provided near the winter high-temperature sand storage tank. The temperature sensor is used to collect the temperature of the sand heating, and the electric valve is connected through a lead wire, and the flow rate of the sand in the sand heater is controlled by the electric valve according to the sand temperature, so as to realize the heating temperature of the sand temperature.

[0012] From the above technical solutions, it can be seen that the present invention has the following advantages compared with the prior art:

[0013] 1. The present invention uses sand as a heat storage material, which has the advantages of low cost, high melting point, good heat capacity value, easy handling or transportation, etc., allowing the storage and distribution of thermal energy from ambient temperature to over 1000 °C. Compared with the commonly used storage materials, sand is more easily obtained and can be obtained from local natural resources, thus eliminating the cost of this part of imported materials and requiring almost no pretreatment, which is more economical.

[0014] 2. The present invention uses a tower-type heliostat, which has a relatively high light concentration ratio, can reflect the sun's rays to the sand heater, and heat the sand to a high temperature above 800 °C; the high temperature can increase the heat storage density of the sand, reduce the required volume of the heat storage tank, reduce the cost and facilitate the application in buildings.

[0015] 3. The concentrating solar seasonal sand high-temperature thermal energy storage heating and hot water system involved in the present invention can achieve seasonal energy storage. It starts collecting solar energy at the beginning of March and stores it in the sand. Part of the energy is used to supply building hot water before the heating season, and these energies are released during the heating season for building heating. The seasonal energy storage characteristics of this system can solve the scheduling problems such as intermittency and unpredictability of solar energy, and it does not require external energy supply, enabling a large degree of building energy conservation.

[0016] 4. In terms of structural design, the concentrating solar seasonal sand high-temperature thermal energy storage heating and hot water system involved in the present invention has a flexible design, simple structure, easy installation, stable operation state and high efficiency. Brief Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the present invention.

[0018] Legend Explanation

[0019] 1. Low-temperature sand storage tank 2. Heat insulation layer

[0020] 3. Winter high-temperature sand storage tank 4. First heat transfer oil heat exchange tube

[0021] 5. Heat insulation layer 6. Summer high-temperature sand storage tank

[0022] 7. Second heat transfer oil heat exchange tube 8. First heat exchanger

[0023] 9. Second heat exchanger 10. Tower-type heliostat

[0024] 11. Sand heater 12, 13, 14, 15. Circulation pump

[0025] 16. Variable-frequency sand pump 17, 18, 19. Electric valve

[0026] 20, 21, 22, 23, 24, 25, 26, 27, 28. Valve

[0027] 29, 30, 31. Temperature sensor 32. Ultrasonic sensor Detailed Embodiment

[0028] The following will describe in detail the embodiments of the present invention with reference to the drawings.

[0029] As Figure 1 shown, a concentrating solar seasonal sand high-temperature thermal energy storage heating and hot water system of the present invention includes a low-temperature sand storage tank 1, a winter high-temperature sand storage tank 3, a summer high-temperature sand storage tank 6, a sand heater 11, a tower-type heliostat 10, a first heat transfer oil heat exchange tube 4, a second heat transfer oil heat exchange tube 7, a first heat exchanger 8 and a second heat exchanger 9.

[0030] The lower part of the low-temperature sand storage tank 1 is funnel-shaped and is placed above the winter high-temperature sand storage tank 3, and the two are connected by the sand heater 11; an electric valve 17 is provided near the low-temperature sand storage tank 1 on the sand heater 11, and a temperature sensor 29 is provided near the winter high-temperature sand storage tank 3. The lower part of the winter high-temperature sand storage tank 3 is funnel-shaped and is placed above the summer high-temperature sand storage tank 6, and the two are connected by a pipeline, and a valve 28 is provided on the pipeline. The winter high-temperature sand storage tank 3 and the summer high-temperature sand storage tank 6 are respectively connected to the variable-frequency sand pump 16 through pipelines, and a circulation loop is formed by connecting the variable-frequency sand pump 16 and the low-temperature sand storage tank 1 through a pipeline; a valve 26 is provided on the pipeline between the winter high-temperature sand storage tank 3 and the variable-frequency sand pump 16, and a valve 27 is provided on the pipeline between the summer high-temperature sand storage tank 6 and the variable-frequency sand pump 16.

[0031] The first heat-conducting oil heat exchange tube 4 is installed inside the winter high-temperature sand storage tank 3. Its heat-conducting oil output end is connected to the heat-conducting oil input end of the first heat exchanger 8 through a circulation pump 14 and a pipeline, and its heat-conducting oil input end is connected to the heat-conducting oil output end of the first heat exchanger 8 through a pipeline; a valve 21 is provided on the pipeline between the circulation pump 14 and the first heat exchanger 8, and a valve 20 is provided on the pipeline between the first heat exchanger 8 and the first heat-conducting oil heat exchange tube 4. The water output end of the first heat exchanger 8 is connected to the water input end of the building heating equipment through a temperature sensor 30 and a pipeline, and its water input end is connected to the water output end of the building heating equipment through a circulation pump 12 and a pipeline; a valve 22 is provided on the pipeline between the temperature sensor 30 and the first heat exchanger 8, and an electric valve 18 is provided on the pipeline between the circulation pump 12 and the first heat exchanger 8.

[0032] The second heat-conducting oil heat exchange tube 7 is installed inside the summer high-temperature sand storage tank 6. Its heat-conducting oil output end is connected to the heat-conducting oil input end of the second heat exchanger 9 through a circulation pump 15 and a pipeline, and its heat-conducting oil input end is connected to the heat-conducting oil output end of the second heat exchanger 9 through a pipeline; a valve 24 is provided on the pipeline between the circulation pump 15 and the second heat exchanger 9, and a valve 23 is provided on the pipeline between the second heat exchanger 9 and the second heat-conducting oil heat exchange tube 7. The water output end of the second heat exchanger 9 is connected to the water input end of the building hot water pipeline through a temperature sensor 31 and a pipeline, and its water input end is connected to the water output end of the building hot water pipeline through a circulation pump 13 and a pipeline; a valve 25 is provided on the pipeline between the temperature sensor 31 and the second heat exchanger 9, and an electric valve 19 is provided on the pipeline between the circulation pump 13 and the second heat exchanger 9.

[0033] An ultrasonic sensor 32 is provided on the top of the summer high-temperature sand storage tank 6.

[0034] Its working principle is as follows: As Figure 1 shown, starting from early March every year, after all the sand is transported to the low-temperature sand storage tank 1, the electric valve 17 and the valve 28 are opened, and the rest of the electric valves and valves are closed; the tower heliostat 10 reflects the sun's rays into the sand heater 11, and the sand flowing out of the low-temperature sand storage tank 1 at 200 °C is quickly heated to 800 °C, and is stored in the summer high-temperature sand storage tank 6 through the winter high-temperature sand storage tank 3. Until the ultrasonic sensor 32 set at the top of the summer high-temperature sand storage tank 6 collects that its inner cavity is full of sand, the valves 23 and 24 are opened, and the control system starts the circulation pump 15 to make the heat-conducting oil in the second heat-conducting oil heat exchange tube 7 fully exchange heat with the sand stored in the inner cavity of the summer high-temperature sand storage tank 6; the electric valve 19 and the valve 25 are opened, and the control system starts the circulation pump 13, and the heat-conducting oil and water exchange heat in the second heat exchanger 9 to heat the water to its delivery temperature and deliver the hot water to the building hot water pipeline for supplying building hot water. The water delivery temperature is collected according to the temperature sensor 31 set at the water circuit end, and the water flow rate is controlled by the electric valve 19 in the circuit. If the water temperature is too low compared to the required heating temperature, the valve 27 is opened, and the variable-frequency sand pump 16 is used to transport the sand in the summer high-temperature sand storage tank 6 to the low-temperature sand storage tank 1, and this cycle is repeated until the end of the heating season.

[0035] In the heating season, the valves 28, 23, 24, 25 and the electric valves 17, 19 are closed, the valves 20 and 21 are opened, and the control system starts the circulation pump 14 to make the heat-conducting oil in the first heat-conducting oil heat exchange tube 4 fully exchange heat with the sand stored in the inner cavity of the winter high-temperature sand storage tank 4; the electric valve 18 and the valve 22 are opened, and the control system starts the circulation pump 12, and the heat-conducting oil and water exchange heat in the first heat exchanger 8 to heat the water to its delivery temperature and deliver it to the building heating equipment for building heating. The water delivery temperature is collected according to the temperature sensor 30 set at the water circuit end, and the water flow rate is controlled by the electric valve 18 in the circuit, so as to realize the heating temperature of the water temperature.

[0036] After the heating season ends until March of the next year, the valves 26 and 27 are opened, and the rest of the valves and electric valves are closed. The control system starts the variable-frequency sand pump 16 to transport all the sand in the winter high-temperature sand storage tank 3 and the summer high-temperature sand storage tank 6 to the low-temperature sand storage tank 1.

[0037] When the temperature sensor 29 measures that the inlet temperature of the winter high-temperature sand storage tank 3 is lower than 800 °C, the electric valve 17 controls to reduce the flow rate of the sand in the sand heater 11 and increase the heat exchange time between the sand and the solar radiation, so as to realize the heating temperature of the sand temperature.

Claims

1. A concentrating solar seasonal sand high-temperature heat storage heating and hot water system, characterized in that It includes a low-temperature sand storage tank, a high-temperature sand storage tank for winter, a high-temperature sand storage tank for summer, a first heat exchanger and its pipeline system, a second heat exchanger and its pipeline system, a sand heater, and a tower heliostat; the lower part of the low-temperature sand storage tank is funnel-shaped and is placed above the high-temperature sand storage tank for winter, and the two are connected by the sand heater; the lower part of the high-temperature sand storage tank for winter is funnel-shaped and is placed above the high-temperature sand storage tank for summer, and the two are connected by a pipeline; the high-temperature sand storage tank for winter and the high-temperature sand storage tank for summer are respectively connected to a variable-frequency sand pump through pipelines, and a pipeline connection between the variable-frequency sand pump and the low-temperature sand storage tank forms a circulation loop; the first heat exchanger and its pipeline system are provided with a heat transfer oil end and a water end, the heat transfer oil end exchanges heat with the sand in the inner cavity of the high-temperature sand storage tank for winter through a circulation pump and a circulation pipeline and forms a circulation loop, and the water end is connected to a building heating device through a circulation pump and a circulation pipeline and forms a circulation loop; the second heat exchanger and its pipeline system are provided with a heat transfer oil end and a water end, the heat transfer oil end exchanges heat with the sand in the inner cavity of the high-temperature sand storage tank for summer through a circulation pump and a circulation pipeline and forms a circulation loop, and the water end is connected to a building hot water pipeline through a circulation pump and a circulation pipeline and forms a circulation loop; for the concentrating solar seasonal sand high-temperature heat storage heating and hot water system, starting from early March every year, the sand flowing out of the low-temperature sand storage tank is heated by the sand heater and stored in the high-temperature sand storage tank for summer until the ultrasonic sensor set at the top of the high-temperature sand storage tank for summer collects that its inner cavity is full of sand; start the circulation pump at the heat transfer oil end of the second heat exchanger and its pipeline system to realize the heat exchange between the sand in the inner cavity of the high-temperature sand storage tank for summer and the heat transfer oil, and then start the circulation pump at the water end to heat the water to its delivery temperature and deliver the hot water to the building hot water pipeline; collect the water delivery temperature according to the temperature sensor set at the water end and control the water flow rate by using the electric valve in the loop. If the water temperature is too low compared with the required heating temperature, use the variable-frequency sand pump to transport the sand in the high-temperature sand storage tank for summer to the low-temperature sand storage tank, and so on in a cycle until the end of the heating season; during the heating season, close the valve on the pipeline connecting the high-temperature sand storage tank for winter and the high-temperature sand storage tank for summer and the second heat exchanger and its pipeline system, start the circulation pump at the heat transfer oil end of the first heat exchanger and its pipeline system to realize the heat exchange between the sand in the inner cavity of the high-temperature sand storage tank for winter and the heat transfer oil, and then start the circulation pump at the water end to heat the water to its delivery temperature and deliver the hot water to the building heating device; collect the water delivery temperature according to the temperature sensor set at the water end and control the water flow rate by using the electric valve in the loop to realize the heating temperature of the water; after the heating season ends at the beginning of March of the next year, close the first heat exchanger and its pipeline system, and use the variable-frequency sand pump to transport the sand in the high-temperature sand storage tank for winter and the high-temperature sand storage tank for summer to the low-temperature sand storage tank.

2. The concentrating solar seasonal sand high-temperature heat storage heating and hot water system according to claim 1, characterized in that, The tower heliostat is composed of a tracking controller, a mechanical support structure, and a reflector, and is arranged around the high-temperature sand storage tank to reflect the sun's rays to the sand heater, and can heat the sand in the sand heater to 800 °C.

3. The concentrating solar seasonal sand high-temperature heat storage heating and hot water system according to claim 1, characterized in that The described sand heater is located at the focus of the described tower heliostat, and an electric valve is provided near the low-temperature sand storage tank, and a temperature sensor is provided near the high-temperature sand storage tank in winter. The temperature sensor is used to collect the temperature of the heated sand, and the electric valve is used to control the sand flow rate in the sand heater according to the sand temperature, so as to realize the heating temperature of the sand temperature.

4. The concentrating solar seasonal sand high-temperature heat storage heating and hot water system according to claim 1, characterized in that The outer sides of the high-temperature sand storage tank in winter, the high-temperature sand storage tank in summer and the pipeline connecting the two are all provided with adiabatic insulation layers, and valves are provided at the pipelines.

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