Device for carrying out cascade energy supply by utilizing solar energy

Abstract

The utility model discloses a device for carrying out cascade energy supply by utilizing solar energy. The device comprises a cold storage tank, a heat collection field, a plurality of hot storage tanks and a heat exchanger, the output end of the cold storage tank is communicated with the heat collection field, the heat collection field is communicated with the heat storage tanks which are connected in parallel, the heat storage tanks are communicated with a heat exchanger through a heat circulating pump, and the outlet end of the heat exchanger is communicated with the cold storage tank; and an electric heater is arranged in each heat storage tank. By means of the structural arrangement of the device, the purpose of efficient operation of the heat collector is achieved, and it is guaranteed that multi-parameter heat utilization requirements are met continuously and stably.

Description

Technical Field

[0001] The utility model belongs to the technical field of industrial heating, and in particular relates to a device for step-by-step energy supply using solar energy. Background Art

[0002] Fossil fuel-based medium- and low-temperature heating and steam supply equipment is gradually being replaced by clean energy devices, represented by wind and solar power. However, wind and solar power resources are unstable and cannot directly provide the high-quality heat source required for industrial production. Currently, the field of medium- and low-temperature solar thermal energy is still in the pilot stage and lacks large-scale industrial application. Low-temperature solar thermal utilization technologies, represented by vacuum tubes and flat-plate solar collectors, do not use concentrating and solar tracking technologies, so they are relatively low-cost and have been widely used for building heating and cooling in areas with good solar resources. However, solar resources directly affect the heat collection efficiency and outlet medium temperature of such technologies, making them difficult to directly apply in the industrial field.

[0003] Patent CN115962505A describes a comprehensive heating and cooling system for government campuses, which falls within the field of heating and cooling technology and also utilizes air energy as a supplement. This patent is primarily applicable to industrial production scenarios with higher heating parameters, using a stepped heating method to meet heating needs across different temperature ranges.

[0004] Patent CN213089897U describes a multi-energy combined medium-deep buried pipe heat source energy storage heating system with a manifold mounted on the top of the base, an electric heating box mounted on top of the manifold; a solar hot water storage tank mounted on top of the electric heating box. Spiral piping within the solar hot water storage tank enables combined geothermal energy storage and heating, ensuring the normal energy supply of the entire system. This patent utilizes electric heating to improve energy quality, fully utilizing the large amount of low-parameter heat collected by non-concentrating solar thermal technology to continuously and stably provide higher-parameter heat to back-end users.

[0005] The heat collection system of patent CN210601842U is a flat-plate solar collector equipped with an anti-freeze device and an anti-overheating system. It aims to solve the problem that the heating system cannot operate safely under overcooling or overheating conditions. It is different from the application scenarios and technical features targeted by this patent.

[0006] Patent CN107120711B has two modes: open and closed circulation, which have higher operating requirements and are different from the operating mode in this patent.

[0007] Patent CN209054628U combines deep geothermal and solar heat to power building heating systems, primarily used in the field of centralized heating systems. This patent utilizes a cascade heating method, using electricity to improve energy quality, to meet diverse heat and steam requirements.

[0008] Patent CN208794527U uses pure solar energy for heating, without external heat supplementation. This patent sets up a large-capacity heat storage device and an electric heating device to maintain stable and continuous operation of the system.

[0009] Patent CN208349387U features a trans-seasonal underground heat storage system that relies on soil heat storage to meet winter heating needs. This patent allows for flexible adjustment of heat storage capacity for different heating scenarios, achieving long-term heat storage and offsetting the volatility of solar energy resources.

[0010] Patent CN208282236 describes a method for controlling and operating a heating system, which continuously provides indoor heating through water pump switching. This patent uses solar energy to meet industrial heat and steam needs, without the need for water pump switching control to change operating modes.

[0011] The energy heating system in patent CN207334869U includes natural gas, off-peak electricity, and solar energy. Its unique feature is the ability to instantly adjust the energy heating system based on load. This patent primarily utilizes long-term heat storage to ensure continuous and stable energy supply.

[0012] Patent CN207112994U utilizes multiple heat source units, including solar energy collection units and industrial waste heat collection units, to heat the heat medium in the thermal storage tank and then supply heat to the heat-consuming units. This patent utilizes a cascade heating mode to specifically meet higher energy demands and maximize the use of renewable energy.

[0013] Traditional high-temperature solar thermal power generation technology has achieved large-scale commercial application in my country. Although low-temperature solar thermal utilization technology developed earlier in my country, for many years it was limited to domestic hot water supply and small-scale industrial demonstrations. This is due to the fact that the system performance of low-temperature solar thermal utilization is directly affected by solar energy resources, making it difficult to meet the requirements of industrial users who require continuous and stable energy supply. Secondly, while the current mainstream non-concentrating solar thermal utilization technology collects a large amount of heat, the energy quality is extremely low, generally around 70°C, and increasing the target temperature causes its collection efficiency to drop rapidly. Therefore, the operating temperature range of non-concentrating solar thermal utilization technology is relatively narrow, making it difficult to meet the diverse heating needs of many industrial users with a single device. Utility Model Content

[0014] The purpose of the utility model is to overcome the problems of the prior art and disclose a device that uses solar energy for cascade energy supply. The structural setting of the device achieves the goal of efficient operation of the collector and ensures continuous and stable adaptation to multi-parameter heat demand.

[0015] The purpose of this utility model is achieved through the following technical solutions:

[0016] A device for cascade energy supply using solar energy, comprising: a cold storage tank, a heat collection field, a plurality of hot storage tanks and a heat exchanger;

[0017] The output end of the cold storage tank is connected to the solar collector field, the solar collector field is connected to the parallel hot storage tanks, each hot storage tank is connected to the heat exchanger via a heat circulation pump, and the outlet end of the heat exchanger is connected to the cold storage tank; an electric heater is provided in each hot storage tank.

[0018] According to a preferred embodiment, the electric heater can be powered by a photovoltaic unit.

[0019] According to a preferred embodiment, a cold circulation pump is provided between the cold storage tank and the solar collector field.

[0020] According to a preferred embodiment, the heat collection field is composed of several heat collectors connected in parallel.

[0021] According to a preferred embodiment, the heat collector includes: a vacuum tube heat collector and a flat plate heat collector.

[0022] According to a preferred embodiment, the inlet and outlet of each heat storage tank are respectively provided with a valve body structure.

[0023] According to a preferred embodiment, the outlet end of the heat circulation pump is provided with a temperature regulating pipe connected to the cold storage tank, and the temperature regulating pipe is provided with a control valve.

[0024] According to a preferred embodiment, two parallel exhaust ports are further provided downstream of the heat circulation pump, including a first exhaust port and a second exhaust port, which can meet the needs of direct steam and hot water use.

[0025] According to a preferred embodiment, a control valve is provided between the first external discharge end and the heat circulation pump, and a pressure reducing valve is provided at the second external discharge end.

[0026] According to a preferred embodiment, a control valve is provided between the heat exchanger and the heat circulation pump.

[0027] The aforementioned main solution and its various further options can be freely combined to form multiple solutions, all of which are solutions that can be adopted and protected by this utility model. After understanding the solution of this utility model, those skilled in the art will understand that there are many combinations based on existing technology and common knowledge, all of which are technical solutions to be protected by this utility model, and these are not exhaustive here.

[0028] Beneficial effects of the utility model:

[0029] 1. By making full use of solar energy resources, heat can be stored for a long time and energy can be supplied continuously and stably.

[0030] 2. The electric heater can achieve step-by-step heating to meet the industrial heat and steam needs above 70°C.

[0031] 3. By setting different heat storage tank parameters, the different heat requirements of back-end users can be met.

[0032] 4. It can supply heat and steam to back-end users at the same time.

[0033] 5. By adjusting the temperature of the cold tank, the inlet temperature of the solar collector field can be kept constant, thus maximizing the efficiency of the solar collector system.

[0034] 6. The comprehensive utilization of two forms of solar energy application, namely, solar thermal and photovoltaic, can ensure 100% solar energy utilization and achieve low-carbon goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the principle structure of the device of the utility model;

[0036] Among them, 1-cold circulation pump, 2-collector field, 3-heat storage tank, 4-heat circulation pump, 5-pressure reducing valve, 6-heat exchanger, 7-temperature regulating pipe, 8-electric heater, 9-cold storage tank, 10-photovoltaic unit. DETAILED DESCRIPTION

[0037] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features within these embodiments may be combined with one another, unless they conflict.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0039] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is typically placed when in use. These terms are intended solely to facilitate the description of this utility model and to simplify the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0041] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0042] In addition, the present invention should point out that, in the present invention, unless the specific structure, connection relationship, position relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, position relationship, power source relationship, etc. involved in the present invention are all known to those skilled in the art based on the existing technology without creative work.

[0043] refer to Figure 1 As shown, the present application discloses a device for cascade energy supply using solar energy, which includes: a cold storage tank 9, a solar collector field 2, several hot storage tanks 3 and a heat exchanger 6.

[0044] The output end of the cold storage tank 9 is connected to the solar collector field 2, and the solar collector field 2 is connected to the parallel hot storage tanks 3. Each hot storage tank 3 is connected to the heat exchanger 6 via the heat circulation pump 4, and the outlet end of the heat exchanger 6 is connected to the cold storage tank 9.

[0045] Preferably, the outlet end of the heat circulation pump 4 is provided with a temperature regulating pipe 7 connected to the cold storage tank 9 , and the temperature regulating pipe 7 is provided with a control valve.

[0046] Preferably, two parallel external discharge ports are further provided downstream of the heat circulation pump 4, including a first external discharge port and a second external discharge port, which are used to discharge the liquid medium and the gaseous medium in the device respectively.

[0047] Furthermore, a control valve is provided between the first outlet port and the heat circulation pump 4, and a pressure reducing valve 5 is provided at the second outlet port. When the circulating medium is water, the pressurized hot water in the heat storage tank 3 can be directly decompressed and released to realize external steam supply.

[0048] Preferably, a control valve is provided between the heat exchanger 6 and the heat circulation pump 4 .

[0049] Preferably, the capacity of each heat storage tank 3 is equivalent to the daily heat load of the back-end user. Each heat storage tank 3 is equipped with an electric heater 8, which not only maintains the temperature of the heat storage tank 3 but also provides heat supplementation when the outlet temperature of the collector field 2 is low on rainy days. Because this system includes multiple heat storage tanks 3, the temperatures of each tank do not necessarily have to be the same. This allows the different heat requirements of back-end users to be met without wasting high-quality heat.

[0050] Preferably, the electric heater is powered by a photovoltaic unit 10. When the user's heat requirement exceeds the maximum temperature of the front-end solar field 2, the electric heater 8 powered by the photovoltaic unit 10 can be used for step-by-step heating, that is, to reheat the circulating medium at the outlet of the solar field 2 to the required temperature at the back-end, thereby fully utilizing solar energy resources.

[0051] Preferably, a cold circulation pump 1 is provided between the cold storage tank 9 and the solar collector field 2 .

[0052] Preferably, the solar field 2 is composed of multiple parallel-connected solar collectors. These collectors can be vacuum tube collectors, flat-plate collectors, or other solar thermal collectors. The pressurized solar field 2 absorbs solar energy to heat the circulating medium, ultimately delivering heat to the heat storage tank 3 after reaching the user's heat demand parameters.

[0053] Preferably, the inlet and outlet ends of each heat storage tank 3 are respectively provided with valve body structures to achieve independent control of each heat storage tank 3 .

[0054] In this application, the cold storage tank 9 is used to receive cold water after heat exchange, and can also receive the circulating medium of the hot storage tank 3, so that the inlet temperature of the collector field 2 is relatively constant, avoiding a significant drop in collector efficiency in winter.

[0055] Example 1

[0056] Under the design conditions, the circulating fluid parameters t1 and p1 at the inlet of the solar collector field 2 are equal to the rated inlet parameters. The cold circulation pump 1 can be used to adjust the circulation flow so that the outlet parameters t2 and p2 of the solar collector field 2 are equal to the rated outlet parameters, ensuring that the solar thermal conversion efficiency of the solar collector field 2 is in a higher range. When the main heat load uses the thermal parameters t4 = t3 = t2 (without considering heat loss), the circulating fluid that reaches the rated outlet parameters will be stored in a certain heat storage tank 3 and flow into the heat exchanger 6 through the heat circulation pump 4 to meet the user's heat load requirements. The circulating medium after heat release enters the cold storage tank 9. In addition, the cold and hot circulating media are mixed through the temperature regulating pipe 7 to ensure that the collector inlet temperature is constant, which can maximize the solar thermal conversion efficiency of the solar collector field.

[0057] Example 2

[0058] On other rainy days or other conditions of low solar radiation, even if the temperature control pipe 7 ensures that the circulating fluid parameters t1 and p1 at the inlet of the collector field 2 are equal to the rated inlet parameters, the outlet parameters t2 and p2 of the collector field 2 may still not reach the rated outlet parameters. This is when the main heat load parameter t4 = t3 > t2. The circulating fluid with parameters t2 and p2 will enter a heat storage tank 3, where it will be heated to the target heat parameter t3 using photovoltaic power before being supplied to the target heat user. This embodiment is also applicable to situations where solar radiation fluctuates significantly throughout the day due to weather. The system can timely switch to different heat storage tanks based on fluctuations in the collector field outlet parameters.

[0059] Example 3

[0060] When back-end heat users have different parameters and different forms of heat demand, if t4, t5, or t6 < t2, and t2 = t3 > t3', the system can flexibly switch heat storage tanks based on the different solar radiation conditions at different times, allowing the circulating medium at different times to be stored in the heat storage tank at t3 or t3', respectively, to maximize the utilization of the low-grade heat from the collector field. The insufficient heat is then converted and supplemented by the electric heater 8 driven by the photovoltaic 10. In particular, if the circulating medium is water, the system can reduce the pressure through the pressure reducing valve 5 and supply steam to the outside, or directly supply hot water to the outside.

[0061] Example 4

[0062] When the heat parameters of the back-end users are higher than the collector operating temperature range, that is, t4>t3, t5>t3, and t6>t3, the circulating medium is heated in the collector field 2 and then enters the heat storage tank 3 with different parameters, where it is further heated by the electric heater 8 to t4, t5, or t6 for storage and utilization.

[0063] This application utilizes a large thermal storage capacity design to ensure continuous and stable energy supply to back-end users. The capacity of a single thermal storage tank is designed to match the daily heat load. The multi-tank design allows for flexible switching based on the day's solar radiation conditions, enabling tiered storage and utilization of heat of varying energy grades, ideally achieving zero-power operation.

[0064] The electricity required for electric heating in this application is provided by the supporting photovoltaic system, ensuring 100% solar energy utilization. Unless the heat storage is exhausted during long rainy days, electricity will be purchased to ensure the back-end heating.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for cascade energy supply using solar energy, characterized in that: The device comprises: a cold storage tank (9), a heat collection field (2), a plurality of hot storage tanks (3) and a heat exchanger (6); The output end of the cold storage tank (9) is connected to the heat collection field (2), the heat collection field (2) is connected to each parallel hot storage tank (3), each hot storage tank (3) is connected to the heat exchanger (6) via a heat circulation pump (4), and the outlet end of the heat exchanger (6) is connected to the cold storage tank (9); and each hot storage tank (3) is provided with an electric heater (8).

2. The device according to claim 1, wherein The electric heater (8) can be powered by a photovoltaic unit (10).

3. The device according to claim 1, wherein A cold circulation pump (1) is provided between the cold storage tank (9) and the heat collection field (2).

4. The device according to claim 1, wherein The heat collecting field (2) is composed of several groups of heat collectors connected in parallel.

5. The device according to claim 4, characterized in that The collector includes but is not limited to: a vacuum tube collector and a flat plate collector.

6. The device according to claim 1, wherein The inlet and outlet ends of each heat storage tank (3) are respectively provided with a valve body structure.

7. The device according to claim 1, wherein The outlet end of the heat circulation pump (4) is provided with a temperature regulating pipe (7) connected to the cold storage tank (9), and the temperature regulating pipe (7) is provided with a control valve.

8. The device according to claim 1, wherein The downstream of the heat circulation pump (4) is also provided with two parallel external discharge ports, including a first external discharge port and a second external discharge port, which can meet the needs of direct steam and hot water use.

9. The device according to claim 8, wherein A control valve is provided between the first external discharge end and the heat circulation pump (4), and a pressure reducing valve (5) is provided at the second external discharge end.

10. The device according to claim 1, wherein A control valve is provided between the heat exchanger (6) and the heat circulation pump (4).

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