Solar-rich region islanded railway building cluster near-zero carbon energy supply system and method thereof

Abstract

The present application relates to a kind of solar energy rich area island type railway building group near zero carbon energy supply system and method thereof.In the system, solar collector and glycol-water plate heat exchanger one side form cycle, high-temperature direct supply water tank and low-temperature water tank and glycol-water plate heat exchanger the other side form cycle;High-temperature direct supply water tank and water-water plate heat exchanger one side form cycle, user and water-water plate heat exchanger the other side form cycle;Solar photovoltaic power generation panel photovoltaic backboard waste heat recovery unit is connected to air source heat pump by air pipe;Air source heat pump and high-temperature direct supply water tank and low-temperature water tank form cycle;High-temperature direct supply water tank and low-temperature water tank and water source heat pump evaporator form cycle, user and water source heat pump condenser form cycle.The system utilizes a variety of renewable energy sources, uses multiple modes to operate, effectively controls emission pollution, reduces power consumption, energy supply is stable, energy efficiency is higher, and can achieve railway station area building group near zero carbon target.

Description

Technical Field

[0001] This invention relates to the field of energy supply technology for railway building complexes, specifically to a near-zero carbon energy supply system and method for an isolated railway building complex in a solar-rich area. Background Technology

[0002] In northern regions, houses along railway lines are located far from urban areas, and heating users are scattered throughout the winter, making direct connection to centralized heating networks impossible. Using a single energy system for self-heating presents numerous drawbacks. For example, traditional oil-fired or coal-fired boilers cause severe pollution, electric boilers are costly and have low energy efficiency, solar energy resources are highly uncertain and volatile, and air-source heat pumps suffer from insufficient heating, increased heat loss, and decreased energy efficiency when outdoor temperatures are too low.

[0003] However, in areas rich in solar energy, with high solar radiation intensity and short periods of continuous cloudy days, it is necessary to prioritize the use of clean solar energy for power generation and thermal storage. Simultaneously, considering the advantages of various clean energy sources, it is crucial to leverage their strengths and compensate for their weaknesses by utilizing them in a coordinated manner. For isolated building complexes, a site-specific clean energy coupled power supply system should be established to improve overall energy utilization efficiency. Therefore, to achieve near-zero carbon emissions during the operation of railway building complexes, it is urgent to establish a more stable, reliable, and economically reasonable energy supply model to overcome the shortcomings of the aforementioned single-energy system and achieve the near-zero carbon target for railway station building complexes. Summary of the Invention

[0004] The purpose of this invention is to provide a near-zero carbon energy supply system and method for isolated railway building complexes in solar-rich areas, so as to solve the defects of using a single energy system for heating in railway building complexes.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A near-zero carbon energy supply system for an isolated railway building complex in a solar-rich area, the system comprising solar collectors, ethylene glycol-water plate heat exchangers, solar photovoltaic panels, air source heat pumps, high-temperature direct-supply water tanks, low-temperature water tanks, water source heat pumps, and water-to-water plate heat exchangers;

[0007] The solar collector forms a circulation loop with one side of the ethylene glycol-water plate heat exchanger, and the high-temperature direct supply water tank and the low-temperature water tank form a circulation loop with the other side of the ethylene glycol-water plate heat exchanger.

[0008] The high-temperature direct supply water tank forms a circulation with one side of the water-to-water plate heat exchanger, and the user forms a circulation with the other side of the water-to-water plate heat exchanger;

[0009] The waste heat recovery unit of the photovoltaic backsheet of the solar photovoltaic power generation panel is connected to the air source heat pump through a duct.

[0010] The air source heat pump forms a circulation system with the high-temperature direct-supply water tank and the low-temperature water tank;

[0011] The high-temperature direct-supply water tank and the low-temperature water tank form a loop with the evaporator of the water source heat pump, and the user forms a loop with the condenser of the water source heat pump.

[0012] Furthermore, the solar photovoltaic power generation panel is connected to the inverter as a power source;

[0013] The inverter is divided into two paths: one path supplies power to the system, and the other path is connected to the battery for energy storage.

[0014] Furthermore, a working fluid pump is provided between the solar collector and the ethylene glycol-water plate heat exchanger, and the circulating working fluid is ethylene glycol.

[0015] Furthermore, a first connecting pipe and a second connecting pipe are provided between the high-temperature direct supply water tank and the low-temperature water tank, and both the first connecting pipe and the second connecting pipe are equipped with butterfly valves;

[0016] The air source heat pump, together with the high-temperature direct-supply water tank, the low-temperature water tank, and the first connecting pipe, forms a circulation system;

[0017] The high-temperature direct-supply water tank, the low-temperature water tank, the second connecting pipe, and the evaporator of the water source heat pump form a circulation system.

[0018] Furthermore, water pumps are installed between the glycol-water plate heat exchanger and the low-temperature water tank, between the air source heat pump and the low-temperature water tank, between the high-temperature direct supply water tank and the water-water plate heat exchanger, between the high-temperature direct supply water tank and the evaporator of the water source heat pump, and between the user and the condenser of the water source heat pump.

[0019] Furthermore, in the circulation formed by the user and the water-to-water plate heat exchanger, electric valves are installed on both the inlet and return water pipes;

[0020] In the cycle formed by the user and the condenser of the water source heat pump, electric valves are installed on both the inlet and outlet water pipes.

[0021] On the other hand, a near-zero carbon energy supply method is provided for isolated railway building complexes in solar-rich areas. This method, implemented based on the aforementioned system, is a solar thermal collector cycle coupled with a high-temperature direct-supply water tank operating independently, including:

[0022] During the day, the solar collector receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector and the ethylene glycol-water plate heat exchanger is started. At the same time, water is drawn from the low-temperature water tank and passed through the ethylene glycol-water plate heat exchanger. The water after heat exchange is stored in the high-temperature direct supply water tank.

[0023] When the water in the high-temperature direct supply water tank reaches the set value, the circulation between the high-temperature direct supply water tank and the water-to-water plate heat exchanger, as well as the circulation between the user and the water-to-water plate heat exchanger, is activated, and heat is transferred to the user for heating and domestic hot water.

[0024] At night, the solar collectors stop operating, and the circulation of the high-temperature direct supply water tank, the low-temperature water tank, the second connecting pipe and the evaporator of the water source heat pump, as well as the circulation between the user and the condenser of the water source heat pump, is started, and the heat is delivered to the user for heating and domestic hot water.

[0025] On the other hand, a near-zero carbon energy supply method is provided for isolated railway building complexes in solar-rich areas. This method, implemented based on the aforementioned system, is a simultaneous operation mode of solar thermal collector cycles and water source heat pump units, including:

[0026] During the day, when the temperature difference between the circulating working fluid entering and leaving the solar collector is greater than the set value, the circulation of the solar collector and the ethylene glycol-water plate heat exchanger is started, and the heat is transferred to the high-temperature direct supply water tank. At the same time, the circulation of the high-temperature direct supply water tank, the low-temperature water tank and the evaporator of the water source heat pump is started.

[0027] Turn on the water source heat pump unit and start the circulation between the user and the condenser of the water source heat pump, so that heat can be transferred to the user for heating and domestic hot water.

[0028] At night, the solar collectors stop operating, and the circulation of the high-temperature direct supply water tank, the low-temperature water tank, the second connecting pipe and the evaporator of the water source heat pump, as well as the circulation of the user and the condenser of the water source heat pump, is started. The high-temperature direct supply water tank and the low-temperature water tank provide heat at the same time, and the heat is delivered to the user for heating and domestic hot water.

[0029] On the other hand, a near-zero carbon energy supply method is provided for isolated railway building complexes in solar-rich areas. This method, implemented based on the aforementioned system, is a combined operation mode of solar thermal collector circulation and air-source and water-source heat pumps, including:

[0030] During the day, the solar collector receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector and the ethylene glycol-water plate heat exchanger is started. At the same time, water is drawn from the low-temperature water tank and passed through the ethylene glycol-water plate heat exchanger. The water after heat exchange is stored in the high-temperature direct supply water tank.

[0031] During the day, the air source heat pump is activated to absorb heat from the waste heat recovery unit of the photovoltaic backsheet of the solar photovoltaic power generation panel, and to start the circulation of the air source heat pump, the high temperature direct supply water tank and the low temperature water tank.

[0032] During the day and night, the water source heat pump runs continuously, circulating the high-temperature direct supply water tank, the low-temperature water tank, the second connecting pipe and the evaporator of the water source heat pump, as well as the user and the condenser of the water source heat pump, so that heat can be delivered to the user for heating and domestic hot water.

[0033] On the other hand, a near-zero carbon energy supply method is provided for isolated railway building complexes in solar-rich areas. This method, implemented based on the aforementioned system, is a combined air-source heat pump and water-source heat pump unit operating mode with a high-temperature direct-supply water tank, including:

[0034] During the day and at night, the air source heat pump runs continuously, absorbing heat from the outdoor air and starting the circulation between the air source heat pump, the high-temperature direct supply water tank, the low-temperature water tank, and the first connecting pipe;

[0035] Meanwhile, the water source heat pump continues to operate, starting the circulation between the high-temperature direct supply water tank, the low-temperature water tank, the second connecting pipe and the evaporator of the water source heat pump, as well as the circulation between the user and the condenser of the water source heat pump, so that heat can be delivered to the user for heating and domestic hot water.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] This invention provides a near-zero carbon energy supply system and method for isolated railway building complexes in solar-rich areas. It comprehensively utilizes renewable energy sources such as solar thermal, photovoltaic, and air source heat pumps, minimizing emissions and effectively reducing electricity costs. Furthermore, by fully leveraging the temporal characteristics of solar and air source heat pumps in solar-rich areas, during days with higher temperatures and stronger solar radiation, it uses solar thermal collectors and air source heat pumps to store heat in water tanks, directly supplying heat to users. Alternatively, it employs a water source heat pump to raise the temperature of low-temperature hot water in the tanks before supplying heat, resulting in a more stable and efficient energy supply, effectively avoiding uncertainties and fluctuations in energy supply. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a system structure diagram of the present invention.

[0040] Figure 2 This is a schematic diagram of the operation of Mode 1 of the present invention.

[0041] Figure 3 This is a schematic diagram of the operation of Mode 2 of the present invention.

[0042] Figure 4 This is a schematic diagram of the operation of Mode 3 of the present invention.

[0043] Figure 5 This is a schematic diagram of the operation of Mode 4 of the present invention.

[0044] The diagram is labeled as follows:

[0045] 1-1 Solar collector, 1-2 Ethylene glycol-water plate heat exchanger;

[0046] 2-1 Solar photovoltaic power generation panel, 2-2 Inverter, 2-3 Energy storage device, 2-4 Photovoltaic backsheet waste heat recovery unit;

[0047] 3-1 Air source heat pump, 3-2 High temperature direct supply water tank, 3-3 Low temperature water tank, 3-4 Water source heat pump, 3-5 Water-to-water plate heat exchanger, 3-6 Air duct, 3-7 First connecting pipe, 3-8 Second connecting pipe;

[0048] 4-1 users;

[0049] SB1 working fluid pump, SB2 first water pump, SB3 second water pump, SB4 third water pump, SB5 fourth water pump, SB6 fifth water pump;

[0050] DDF1 is the first electric valve, DDF2 is the second electric valve, DDF3 is the third electric valve, and DDF4 is the fourth electric valve. Detailed Implementation

[0051] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0052] In the description of this invention, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Of course, such terms can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in a sequence other than those illustrated or described herein.

[0053] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0054] This invention provides a near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas. It comprehensively utilizes renewable energy sources such as solar thermal, photovoltaic, and air energy to construct an integrated energy supply system that combines air energy, solar energy, energy storage, and heat pump efficiency enhancement. This system provides electricity, heating, and domestic hot water to the railway station area (isolated) throughout the year, improves the overall energy efficiency of the energy supply system for railway station building complexes in northern China, and achieves near-zero carbon emissions for railway station building complexes.

[0055] The main equipment in this system includes a solar collector 1-1, an ethylene glycol-water plate heat exchanger 1-2, a solar photovoltaic panel 2-1, an air source heat pump 3-1, a high-temperature direct-supply water tank 3-2, a low-temperature water tank 3-3, a water source heat pump 3-4, and a water-to-water plate heat exchanger 3-5. The various devices are connected via liquid and electrical routes, forming several circulation loops. Valves, pumps, and other components along these loops allow the loops to switch between different operating modes. Specifically: Solar collector 1-1 forms a circulation with one side of ethylene glycol-water plate heat exchanger 1-2; high-temperature direct supply water tank 3-2, low-temperature water tank 3-3, and first connecting pipe 3-7 form a circulation with the other side of ethylene glycol-water plate heat exchanger 1-2; high-temperature direct supply water tank 3-2 forms a circulation with one side of water-water plate heat exchanger 3-5; user 4-1 forms a circulation with the other side of water-water plate heat exchanger 3-5; the photovoltaic backsheet waste heat recovery unit 2-4 of solar photovoltaic power generation panel 2-1 is connected to air source heat pump 3-1 through duct 3-6; air source heat pump 3-1 forms a circulation with high-temperature direct supply water tank 3-2, low-temperature water tank 3-3, and first connecting pipe 3-7; high-temperature direct supply water tank 3-2, low-temperature water tank 3-3, and second connecting pipe 3-8 form a circulation with the evaporator of water source heat pump 3-4; user 4-1 forms a circulation with the condenser of water source heat pump 3-4.

[0056] The solar photovoltaic power generation panel 2-1 is connected to the inverter 2-2 as a power source. The inverter 2-2 is divided into two paths: one path supplies power to the system, and the other path is connected to the battery 2-3 for energy storage.

[0057] The switching components include: a working fluid pump SB1 is installed between the solar collector 1-1 and the ethylene glycol-water plate heat exchanger 1-2, with ethylene glycol as the circulating working fluid. Pumps are installed between the ethylene glycol-water plate heat exchanger 1-2 and the low-temperature water tank 3-3, between the air source heat pump 3-1 and the low-temperature water tank 3-3, between the high-temperature direct supply water tank 3-2 and the water-water plate heat exchanger 3-5, between the high-temperature direct supply water tank 3-2 and the evaporator of the water source heat pump 3-4, and between user 4-1 and the condenser of the water source heat pump 3-4. Butterfly valves are installed on both the first connecting pipe 3-7 and the second connecting pipe 3-8. In the cycle formed by user 4-1 and the water-water plate heat exchanger 3-5, electric valves are installed on both the inlet and return water pipes; in the cycle formed by user 4-1 and the condenser of the water source heat pump 3-4, electric valves are installed on both the inlet and return water pipes.

[0058] Specifically, such as Figure 1 This system comprises four main modules: production capacity system, energy storage system, efficiency enhancement system, and energy consumption system.

[0059] The production capacity system comprises three modules: a solar thermal production capacity module, a photovoltaic production capacity module, and an air source heat pump production capacity module. The solar thermal production capacity module consists of a solar collector 1-1, an ethylene glycol-water plate heat exchanger 1-2, a working fluid pump SB1, and a first water pump SB2. The photovoltaic production capacity module consists of a solar photovoltaic panel 2-1, an inverter 2-2, and an energy storage device 2-3. The air source heat pump production capacity module is an air source heat pump 3-1. This invention separates the solar thermal and photovoltaic production capacity modules, unlike the combined modules in existing technologies. Generally, the principles of solar thermal and photovoltaic conversion are different; solar thermal conversion requires a working fluid to flow through the solar thermal panel, while photovoltaic conversion does not. By separating the solar thermal and photovoltaic production capacity modules, this invention can provide more operating modes through different control logics.

[0060] The energy storage system includes a water tank thermal storage module and an energy storage module. The water tank thermal storage module consists of a high-temperature direct-supply water tank 3-2 and a low-temperature water tank 3-3. The energy storage module consists of a solar photovoltaic power generation panel 2-1, an inverter 2-2, and an energy storage device 2-3. This invention adopts a system architecture with the high-temperature direct-supply water tank and the low-temperature water tank operating in tandem. On the working fluid pump side of the solar thermal collector circulation, water is drawn from the low-temperature water tank, heat-exchanged, and then supplied to the high-temperature direct-supply water tank. The water then flows back to the low-temperature water tank through a circulation pipe, which facilitates energy grading of the heat from the high and low temperature water tanks. For the evaporator of the water source heat pump, water can be drawn from the high-temperature direct-supply water tank. After absorbing the low-temperature heat source from the high-temperature direct-supply water tank through the evaporator, the water flows back to the low-temperature water tank through a circulation pipe. Drawing water from the relatively higher-temperature water tank increases the temperature of the heat source section, which is beneficial for improving the energy efficiency of the water source heat pump.

[0061] The efficiency enhancement system includes a photovoltaic backsheet waste heat utilization unit and a water source heat pump efficiency enhancement module. The photovoltaic backsheet waste heat utilization unit consists of a solar photovoltaic power generation panel 2-1 and a duct 3-6. The water source heat pump efficiency enhancement module consists of a high-temperature direct supply water tank 3-2, a low-temperature water tank 3-3, and a water source heat pump 3-4.

[0062] The energy system includes a direct heating system and a combined heating system. The direct heating system consists of a high-temperature direct supply water tank 3-2, a water-to-water plate heat exchanger 3-5, and a user 4-1. The combined heating system consists of a high-temperature direct supply water tank 3-2, a low-temperature water tank 3-2, a water source heat pump 3-4, and a user.

[0063] The four modules are interconnected and coordinated by utilizing the characteristics of various renewable energy sources to form an independent and complete near-zero carbon energy supply model.

[0064] The above systems all use equipment and materials commonly used in this field.

[0065] like Figure 1 Specifically, this system can form a centralized functional loop, including:

[0066] Solar thermal heating cycle: Solar collector 1-1 is connected to the left side of ethylene glycol-water plate heat exchanger 1-2 via working fluid pump SB1. The circulating working fluid is ethylene glycol, and working fluid pump SB1 is installed on the circulation pipeline. The right side of ethylene glycol-water plate heat exchanger 1-2 is connected to high-temperature direct supply water tank 3-2, and a first water pump SB2 is installed on the circulation pipeline. High-temperature direct supply water tank 3-2 is connected to water-water plate heat exchanger 3-5 for heat exchange to user 4-1. Unlike traditional direct heating, this invention adopts a closed-loop indirect solar heating method, effectively avoiding the problem of lack of antifreeze function in direct heating. In direct heating, glass tubes are prone to freezing and cracking in low-temperature environments, thus affecting overall heating and supply, which is not conducive to use in northern regions.

[0067] Photovoltaic power supply unit: Solar photovoltaic power generation panel 2-1 is connected to inverter 2-2 as a power source. From the inverter, there are two paths. One path directly supplies energy to the energy-consuming equipment and users, including SB1~SB6, air source heat pump 3-1, water source heat pump 3-4, DDF1~DDF4. The other path connects the inverter 2-2 to the energy storage device 2-3 (battery) for energy storage, and then connects to the energy-consuming equipment and users through the battery.

[0068] Air source heat pump heating cycle: A photovoltaic backsheet waste heat recovery unit 2-4 is installed under the photovoltaic backsheet. Hot air, as a low-temperature heat source, is delivered to the air source heat pump 3-1 through the air duct 3-6, where the heat is increased. Simultaneously, the second water pump SB-3 draws water from the low-temperature water tank 3-3, exchanges heat through the air source heat pump 3-1, and the water flows to the high-temperature direct supply water tank 3-2. The high-temperature direct supply water tank 3-2 is connected to the first connecting pipe 3-7 of the low-temperature water tank 3-3, allowing water from the high-temperature direct supply water tank 3-2 to flow to the low-temperature water tank 3-3. Through this cycle, the water in the high and low temperature water tanks can be heated by the air source heat pump 3-1 for heat storage. This invention features heat sources with different coupling forms at the air source heat pump evaporator end. One is the daytime heating mode, in which a fan provides power to exchange heat with the working fluid pipeline to increase the air temperature on the evaporator side of the air source heat pump, thereby reducing the frosting problem of the air source heat pump. Secondly, there is the nighttime heating mode. This mode utilizes the heat stored in the water tank during the day to provide a higher-temperature working fluid to the evaporator side of the water source heat pump at night, thereby improving the energy efficiency of the water source heat pump and the entire heating system. In summary, the low-temperature heat source of this invention is the low-temperature air from the photovoltaic backsheet provided to the air source heat pump. The heat pump heats the water in the high and low temperature water tanks, which is then further heated by the water source heat pump before being supplied to the user. Therefore, for the user end, the heating source is a combination of multiple energy forms, including solar energy, air energy, and water tank thermal storage, rather than a single form of air thermal energy.

[0069] High-temperature water tank direct supply circulation: According to the energy priority relationship, this near-zero carbon composite energy supply system prioritizes the use of clean and environmentally friendly solar energy resources during operation. When the water temperature of the high-temperature direct supply water tank reaches 60℃, the third water pump SB4 is turned on and directly supplies water to user 4-1 through the water-to-water plate heat exchanger 3-5. At this time, the first electric valve DDF1 and the second electric valve DDF2 are opened, and the third electric valve DDF3 and the fourth electric valve DDF4 are closed.

[0070] Water source heat pump efficiency enhancement cycle: Water source heat pump 3-4 draws water from high temperature direct supply water tank 3-2, exchanges heat with the evaporator inside water source heat pump 3-4, and then flows to low temperature water tank 3-3. Through the energy enhancement of water source heat pump 3-4, hot water is supplied to user 4-1. At this time, the third electric valve DDF3 and the fourth electric valve DDF4 are opened, and the first electric valve DDF1 and the second electric valve DDF2 are closed.

[0071] Based on energy priority, this near-zero carbon composite energy supply system prioritizes the use of clean and environmentally friendly solar energy resources during operation. When solar energy resources cannot meet the users' heating and domestic hot water needs, air source heat pumps or hot water units are used for auxiliary energy supply, mainly including the following four operating modes:

[0072] The solar thermal collector circulation coupled with a high-temperature direct supply water tank operates in a standalone mode, including:

[0073] 1. During the day, the solar collector 1-1 receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector 1-1 and the ethylene glycol-water plate heat exchanger 1-2 is started. At the same time, water is drawn from the low-temperature water tank 3-3 and passed through the ethylene glycol-water plate heat exchanger 1-2. The water after heat exchange is stored in the high-temperature direct supply water tank 3-2.

[0074] 2. When the water in the high-temperature direct supply water tank 3-2 reaches the set value, the circulation between the high-temperature direct supply water tank 3-2 and the water-to-water plate heat exchanger 3-5, as well as the circulation between user 4-1 and the water-to-water plate heat exchanger 3-5, is started, and heat is transferred to user 4-1 for heating and domestic hot water.

[0075] 3. At night, solar collector 1-1 stops operating, and the circulation of the evaporators of high-temperature direct supply water tank 3-2, low-temperature water tank 3-3 and water source heat pump 3-4, as well as the circulation of the condenser of user 4-1 and water source heat pump 3-4, is started, and heat is transferred to user 4-1 for heating and domestic hot water.

[0076] Simultaneous operation modes of solar thermal collectors and water source heat pump units include:

[0077] 1. During the day, when the temperature difference between the circulating working fluid entering and exiting the solar collector 1-1 is greater than the set value, the circulation of the solar collector 1-1 and the ethylene glycol-water plate heat exchanger 1-2 is started, and the heat is transferred to the high-temperature direct supply water tank 3-2. At the same time, the circulation of the evaporators of the high-temperature direct supply water tank 3-2, the low-temperature water tank 3-3 and the water source heat pump 3-4 is started.

[0078] 2. Start the water source heat pump unit 3-4 and start the circulation between the condenser of user 4-1 and water source heat pump 3-4, so that heat can be transferred to user 4-1 for heating and domestic hot water.

[0079] 3. At night, solar collector 1-1 stops operating, and the circulation of the evaporators of high-temperature direct supply water tank 3-2, low-temperature water tank 3-3 and water source heat pump 3-4, as well as the circulation of the condenser of user 4-1 and water source heat pump 3-4, is started. High-temperature direct supply water tank 3-2 and low-temperature water tank 3-3 provide heat at the same time, and the heat is delivered to user 4-1 for heating and domestic hot water.

[0080] The combined operation mode of solar thermal collector circulation and air-source and water-source heat pumps includes:

[0081] 1. During the day, the solar collector 1-1 receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector 1-1 and the ethylene glycol-water plate heat exchanger 1-2 is started. At the same time, water is drawn from the low-temperature water tank 3-3 and passed through the ethylene glycol-water plate heat exchanger 1-2. The water after heat exchange is stored in the high-temperature direct supply water tank 3-2.

[0082] 2. During the day, the air source heat pump 3-1 is started to absorb heat from the waste heat recovery unit 2-4 of the photovoltaic back panel of the solar photovoltaic power generation panel 2-1, and to start the circulation of the air source heat pump 3-1, the high temperature direct supply water tank 3-2 and the low temperature water tank 3-3.

[0083] 3. During the day and night, the water source heat pump 3-4 runs continuously, opening the circulation between the high-temperature direct supply water tank 3-2, the low-temperature water tank 3-3 and the evaporator of the water source heat pump 3-4, as well as the circulation between user 4-1 and the condenser of the water source heat pump 3-4, so that heat can be delivered to user 4-1 for heating and domestic hot water.

[0084] The operating modes of air source heat pump combined with water source heat pump units include:

[0085] 1. During the day and at night, the air source heat pump 3-1 runs continuously, absorbing heat from the outdoor air and starting the circulation of the air source heat pump 3-1, the high temperature direct supply water tank 3-2 and the low temperature water tank 3-3;

[0086] 2. At the same time, the water source heat pump 3-4 continues to operate, starting the circulation of the high-temperature direct supply water tank 3-2, the low-temperature water tank 3-3 and the evaporator of the water source heat pump 3-4, as well as the circulation of the user 4-1 and the condenser of the water source heat pump 3-4, so that heat can be transferred to the user 4-1 for heating and domestic hot water.

[0087] In each mode, during the day, the solar photovoltaic panel 2-1 generates electricity from solar energy, which is then converted from direct current to alternating current by the inverter 2-2. A portion of this electricity is supplied to the electrical facilities of the aforementioned system, while the remainder is stored in the battery. At night, the battery supplies power to the electrical facilities of the aforementioned system.

[0088] like Figure 2 When the weather is sunny and solar radiation is sufficient, the preferred operating mode is a solar thermal collector circulation coupled with a high-temperature direct supply water tank operating independently. The control method for this mode is as follows:

[0089] (1) The daytime solar collector 1-1 receives solar energy when the solar radiation intensity reaches 200W / m 2 At the same time, the working fluid pump SB1 starts, and the working fluid on the heat collection side flows clockwise from the working fluid pump SB1 to the ethylene glycol-water plate heat exchanger 1-2. At the same time, SB2 starts, drawing water from the low-temperature water tank and passing it through the ethylene glycol-water plate heat exchanger 1-2. The water after heat exchange is stored in the high-temperature direct supply water tank 3-2.

[0090] (2) When the water in the high temperature direct supply water tank 3-2 reaches 60℃, turn on the third water pump SB4 on the other side of the high temperature direct supply water tank 3-2. After that, the heat from the high temperature direct supply water tank 3-2 is transferred to the user 4-1 for heating and domestic hot water through the water-to-water plate heat exchanger 3-5. At this time, the electric valves DDF1 and DDF2 are turned on and DDF3 and DDF4 are turned off.

[0091] (3) At night, the solar thermal cycle does not run. Stop water pumps SB1 and SB2, close the butterfly valve on the first connecting pipe 3-7, and use the energy stored in the high-temperature direct supply water tank 3-2 during the day as a low-temperature heat source. Start the fourth water pump SB5 to draw water from the high-temperature direct supply water tank 3-2. After the water source heat pump 3-4 unit absorbs heat, the water flows back to the low-temperature water tank 3-3. After the water source heat pump 3-4 heats up, open the electric valves DDF3 and DDF4 and the fifth water pump SB6 to deliver the heat to the users, and close the electric valves DDF1 and DDF2.

[0092] (4) During the day, solar photovoltaic panels 2-1 generate electricity from solar energy, which is then converted from direct current to alternating current by inverter 2-2. A portion of this electricity is supplied to SB1, SB2, SB4, DDF1, DDF2 and other electrical facilities on the user side of the system, while the remainder is stored in energy storage device 2-3. At night, energy storage device 2-3 supplies power to water source heat pumps 3-4, SB5, SB6, DDF3, DDF4 and the user.

[0093] This mode utilizes the high intensity of solar radiation during the day, storing the heat from the solar collector cycle in a water tank. It prioritizes drawing water from the low-temperature water tank for heat exchange with the solar collector, and then transports the high-temperature hot water to the high-temperature direct supply water tank. During the day, the high-temperature water tank directly supplies the user, while at night, a water source heat pump extracts the stored heat from the high-temperature water tank to further raise the temperature to a certain level before supplying the user. This dual-tank mode facilitates energy grading of the stored heat, reduces energy mixing, and helps improve the overall energy utilization efficiency of the system under this condition.

[0094] like Figure 3 When weather conditions are good and solar radiation intensity is low, using solar thermal collectors alone may not meet the standard for direct supply. In this case, the solar thermal collector circulation and water source heat pump unit will be operated simultaneously. In this mode, the air source heat pump unit 3-1 and the water-to-water plate heat exchanger 3-5 will not be turned on.

[0095] (1) When the temperature difference between the ethylene glycol solution entering and exiting the solar collector 1-1 is greater than 5°C, the ethylene glycol working fluid pump SB1 is started. The ethylene glycol working fluid is heated by the solar collector 1-1, and then the heat is transferred to the high-temperature direct supply water tank 3-2 through the ethylene glycol-water plate heat exchanger 1-2. At the same time, the fourth water pump SB5 connecting the high-temperature direct supply water tank 3-2 and the low-temperature water tank 3-3 is turned on.

[0096] (2) Turn on the water source heat pump 3-4. The water source heat pump evaporator further transfers the heat from the water tank to the condenser side of the water source heat pump. The water source heat pump heat exchange system further increases the temperature of the hot water from the high-temperature direct supply water tank 3-2. Then, turn on the electric valves DDF3 and DDF4, turn on the fifth water pump SB6, and finally deliver the heat to the user 4-1.

[0097] (3) The solar thermal cycle is not turned on at night. Only the heat stored in the high and low temperature water tanks during the day is used for heating. The hot water in the high temperature direct supply water tank 3-2 is transported to the water source heat pump evaporator by the fourth water pump SB5. The low temperature water tank 3-3 is connected to the high temperature direct supply water tank 3-2 through the second connecting pipe 3-8. The water source heat pump 3-4 is turned on. The water source heat pump evaporator further transfers the heat of the water tank to the water source heat pump condenser. After the water temperature rises, the electric valves DDF3 and DDF4 are turned on, the fifth water pump SB6 is turned on, and finally the heat is delivered to the user 4-1.

[0098] (4) During the day, solar photovoltaic panels 2-1 generate electricity from solar energy, which is then converted from direct current to alternating current by inverter 2-2. A portion of this electricity is supplied to SB1, SB2, SB5, SB6, DDF3, DDF4, and other electrical facilities of user 4-1 in the aforementioned system, while the remainder is stored in energy storage device 2-3. At night, energy storage device 2-3 supplies power to water source heat pumps 3-4, SB2, SB5, DDF3, DDF4, and users.

[0099] Even when the radiation intensity is not high, this mode still prioritizes the use of solar energy and uses its stored heat as a low-temperature heat source. Combined with the high coefficient of performance of water source heat pumps, it meets the user's heating and domestic hot water needs.

[0100] like Figure 4 When weather conditions are unfavorable and solar radiation is insufficient, the temperature of hot water stored by solar thermal collectors alone is insufficient to meet the temperature required for the water source heat pump evaporator to absorb low-temperature heat sources. Therefore, it is necessary to combine solar thermal collectors and air source heat pumps to store heat in the water tank at the same time.

[0101] (1) During the day, local solar energy resources are still prioritized for maximum utilization. During the daytime, solar collector 1-1 receives solar energy. When the solar radiation intensity reaches 200W / m 2 At this time, the working fluid pump SB1 starts, and the working fluid on the heat collector side flows clockwise from the working fluid pump SB1 to the ethylene glycol-water plate heat exchanger 1-2. At the same time, the first water pump SB2 starts, drawing water from the low-temperature water tank 3-3 and passing it through the ethylene glycol-water plate heat exchanger 1-2. The water after heat exchange is stored in the high-temperature direct supply water tank 3-2.

[0102] (2) Since the water temperature of the high-temperature direct supply water tank 3-2 does not meet the heat absorption temperature requirements of the water source heat pump 3-4, the air source heat pump 3-1 needs to be run during the day. First, heat is absorbed from the photovoltaic back panel waste heat recovery unit 2-4, and after being heated by the air source heat pump 3-1, it exchanges heat with water absorbed from the low-temperature water tank 3-3. The water after heat exchange flows to the high-temperature direct supply water tank 3-2 for supplementary heating. At this time, the butterfly valve of the first connecting pipe 3-7 is opened.

[0103] (3) During the day and night, the water source heat pump 3-4 runs continuously, and the fourth water pump SB5 is activated to draw water from the high-temperature direct supply water tank 3-2. After absorbing heat through the evaporator of the water source heat pump 3-4 unit, the water flows back to the low-temperature water tank 3-3, and then flows back to the high-temperature direct supply water tank 3-2 via the second connecting pipe 3-8. After the water source heat pump 3-4 heats up the water, the electric valves DDF3 and DDF4 and the fifth water pump SB6 are activated to supply heat to users, and the electric valves DDF1 and DDF2 are closed. At night, the solar thermal collector circulation does not run, the water pumps SB1 and SB2 are stopped, and the butterfly valve of the first connecting pipe 3-7 is closed.

[0104] (4) In this working condition, the solar photovoltaic power generation panel 2-1 receives solar energy to generate electricity, and the DC power is converted into AC power by the inverter 2-2. During the day, the DC power is directly supplied to various electrical equipment and users from the inverter 2-2. If there is excess electricity, it will be stored in the energy storage device and supplied to the corresponding equipment and users at night.

[0105] Even when radiation intensity is insufficient, this mode still prioritizes the use of solar thermal collectors coupled with air source heat pumps to store heat as a low-temperature heat source. Combined with the high coefficient of performance of water source heat pumps, it meets users' heating and domestic hot water needs.

[0106] like Figure 5 When there are cloudy or rainy days, there is almost no solar radiation. At this time, the air source heat pump unit is started to store heat in the high-temperature direct supply water tank. At the same time, the water source heat pump unit draws water from the high-temperature direct supply water tank and exchanges heat with the evaporator of the water source heat pump to further increase the water temperature before supplying it to the heat users.

[0107] (1) During the day and at night, the air source heat pump 3-1 first absorbs heat from the outdoor air, and after the heat is raised, it exchanges heat with water drawn from the low temperature water tank 3-3. The water after heat exchange flows to the high temperature direct supply water tank 3-2 for heat storage. At this time, the butterfly valve of the first connecting pipe 3-7 is opened.

[0108] (2) The water source heat pump 3-4 operates continuously under this condition. Simultaneously, the fourth water pump SB5 draws water from the high-temperature direct supply water tank 3-2. After absorbing heat through the evaporator of the water source heat pump 3-4 unit, the water flows back to the low-temperature water tank 3-3 and then back to the high-temperature direct supply water tank 3-2 via the second connecting pipe 3-8. Afterward, the water source heat pump 3-4 heats the water, opening electric valves DDF3 and DDF4 and the fifth water pump SB6 to supply heat to users, while closing electric valves DDF1 and DDF2. At night, the solar thermal collector circulation does not operate; water pumps SB1 and SB2 are stopped, and the butterfly valve on the first connecting pipe 3-7 is closed.

[0109] (3) Under this operating condition, the solar photovoltaic power generation panel 2-1 cannot generate electricity during the day. During the day and night, it can only supply electricity to various electrical equipment and users from the energy storage device 2-3. If the energy storage device is insufficient, external power will be introduced to supply the electrical equipment and users of the system.

[0110] Since solar-rich areas rarely experience consecutive cloudy or rainy days, the four commonly used operating modes of the near-zero carbon composite energy supply system comprehensively utilize various clean energy sources to ensure a continuous and stable output of heating and domestic hot water for users. At the same time, it maximizes the use of solar energy resources in solar-rich areas to achieve near-zero carbon emissions for island-style building complexes.

[0111] This system, by adopting the above-mentioned multiple operating modes, has the following technical advantages:

[0112] 1. Fluctuations are the most important factor affecting the safe and stable operation of the system. This system fully utilizes the temporal characteristics of solar and air energy in solar-rich areas. During the daytime when temperatures are high and solar radiation is strong, it uses solar thermal collectors and air-source heat pumps to store heat in the water tank, directly supplying heat to users, or uses a water-source heat pump to raise the temperature of the low-temperature hot water in the tank before supplying heat. The coupling of solar collectors and heat pump units fully leverages the advantages of both solar thermal and heat pump technologies, further addressing the limitations imposed by seasonal and weather factors when using solar and air thermal energy alone. This results in a more stable energy supply and higher efficiency.

[0113] 2. This system incorporates a photovoltaic backsheet waste heat recovery device. Fluid channels are laid on the backsheet of the photovoltaic modules to increase airflow velocity and remove the heat generated by the photovoltaic panels. The waste heat recovery unit not only reduces the temperature of the photovoltaic modules, improving their lifespan, photoelectric conversion efficiency, and overall solar energy utilization efficiency, but also effectively utilizes the heat carried away by the air as an evaporative heat source for the air source heat pump. This improves the air source heat pump's energy efficiency ratio, reduces its susceptibility to ambient temperature limitations, and decreases the required air source heat pump capacity.

[0114] 3. This system employs a high-temperature direct-supply water tank and a low-temperature water tank. In this dual-tank configuration, water is drawn from the low-temperature water tank on the pump side of the solar collector's circulating working fluid. After heat exchange, the water is supplied to the high-temperature water tank and then flows back to the low-temperature water tank through the first connecting pipe. This facilitates energy stratification of the heat from the high and low temperature tanks. For the water source heat pump evaporator, water can be drawn from the high-temperature water tank, absorbed from the low-temperature heat source in the high-temperature water tank, and then flowed back to the low-temperature water tank through the second connecting pipe. The relatively higher water tank draws water, increasing the temperature of the heat source section and improving the energy efficiency of the water source heat pump. Therefore, the dual-tank system mode is beneficial for energy stratification and improves the overall system's energy efficiency ratio.

[0115] 4. This system employs photovoltaic power generation devices to generate electricity to power energy-consuming equipment and users when solar radiation intensity is high. Excess electricity is stored in energy storage devices for use at night or on cloudy days. The system also utilizes thermal and electrical storage devices, organically coupling heat and electricity demand with production output. This self-sufficiency in energy production solves the problem of energy supply to isolated areas of railway station complexes, while simultaneously reducing carbon emissions in the station areas, achieving a near-zero carbon goal for railway station complexes.

[0116] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas, characterized by: The system includes a solar collector (1-1), an ethylene glycol-water plate heat exchanger (1-2), a solar photovoltaic power generation panel (2-1), an air source heat pump (3-1), a high-temperature direct-supply water tank (3-2), a low-temperature water tank (3-3), a water source heat pump (3-4), and a water-to-water plate heat exchanger (3-5). The solar collector (1-1) and the ethylene glycol-water plate heat exchanger (1-2) form a circulation on one side, and the high-temperature direct supply water tank (3-2) and the low-temperature water tank (3-3) and the ethylene glycol-water plate heat exchanger (1-2) form a circulation on the other side. The high-temperature direct-supply water tank (3-2) forms a circulation with one side of the water-to-water plate heat exchanger (3-5), and the user (4-1) forms a circulation with the other side of the water-to-water plate heat exchanger (3-5); the high-temperature direct-supply water tank (3-2) and the low-temperature water tank (3-3) form a dual-tank system for system energy grading; the high-temperature direct-supply water tank (3-2) and the low-temperature water tank (3-3) form a circulation through a first connecting pipe (3-7) and a second connecting pipe (3-8), and both the first connecting pipe (3-7) and the second connecting pipe (3-8) are equipped with butterfly valves; The waste heat recovery unit (2-4) of the photovoltaic backsheet of the solar photovoltaic power generation panel (2-1) is connected to the air source heat pump (3-1) through the air duct (3-6). The air source heat pump (3-1) forms a circulation system with the high-temperature direct-supply water tank (3-2) and the low-temperature water tank (3-3); The high-temperature direct-supply water tank (3-2) and the low-temperature water tank (3-3) form a cycle with the evaporator of the water source heat pump (3-4), and the user (4-1) forms a cycle with the condenser of the water source heat pump (3-4).

2. The near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas according to claim 1, characterized in that: The solar photovoltaic power generation panel (2-1) is connected to the inverter (2-2) as a power source. The inverter (2-2) is divided into two paths: one path supplies power to the system, and the other path is connected to the battery (2-3) for energy storage.

3. The near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas according to claim 1, characterized in that: A working fluid pump (SB1) is provided between the solar collector (1-1) and the ethylene glycol-water plate heat exchanger (1-2), and the circulating working fluid is ethylene glycol.

4. The near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas according to claim 1, characterized in that: Water pumps are installed between the ethylene glycol-water plate heat exchanger (1-2) and the low-temperature water tank (3-3), between the air source heat pump (3-1) and the low-temperature water tank (3-3), between the high-temperature direct supply water tank (3-2) and the water-water plate heat exchanger (3-5), between the high-temperature direct supply water tank (3-2) and the evaporator of the water source heat pump (3-4), and between the user (4-1) and the condenser of the water source heat pump (3-4).

5. The near-zero carbon energy supply system for isolated railway building complexes in solar-rich areas according to claim 1, characterized in that: In the cycle formed by the user (4-1) and the water-to-water plate heat exchanger (3-5), electric valves are installed on both the inlet and return water pipes; In the cycle formed by the user (4-1) and the condenser of the water source heat pump (3-4), electric valves are installed on both the inlet and outlet water pipes.

6. A near-zero carbon energy supply method for isolated railway building complexes in solar-rich areas, characterized by: The method is implemented based on the system described in claim 1, and is a solar thermal collection cycle coupled with a high-temperature direct-supply water tank operating mode, including: During the day, the solar collector (1-1) receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector (1-1) and the ethylene glycol-water plate heat exchanger (1-2) is started. At the same time, water is drawn from the low-temperature water tank (3-3) and passed through the ethylene glycol-water plate heat exchanger (1-2). The water after heat exchange is stored in the high-temperature direct supply water tank (3-2). When the water in the high-temperature direct supply water tank (3-2) reaches the set value, the circulation between the high-temperature direct supply water tank (3-2) and the water-to-water plate heat exchanger (3-5) and the user (4-1) and the water-to-water plate heat exchanger (3-5) are started, and the heat is transferred to the user (4-1) for heating and domestic hot water. At night, the solar collector (1-1) stops operating, and the circulation of the evaporators of the high-temperature direct supply water tank (3-2), the low-temperature water tank (3-3), and the water source heat pump (3-4) is turned on, as well as the circulation of the condenser of the user (4-1) and the water source heat pump (3-4), so that heat is delivered to the user (4-1) for heating and domestic hot water.

7. A near-zero carbon energy supply method for isolated railway building complexes in solar-rich areas, characterized by: The method is implemented based on the system described in claim 1, and is a mode in which the solar thermal collector cycle and the water source heat pump unit operate simultaneously, including: During the day, when the temperature difference between the circulating working fluid entering and exiting the solar collector (1-1) is greater than the set value, the circulation of the solar collector (1-1) and the ethylene glycol-water plate heat exchanger (1-2) is started, and the heat is transferred to the high-temperature direct supply water tank (3-2). At the same time, the circulation of the evaporators of the high-temperature direct supply water tank (3-2), the low-temperature water tank (3-3) and the water source heat pump (3-4) is started, and the high-temperature direct supply water tank (3-2) and the low-temperature water tank (3-3) store heat at the same time. Turn on the water source heat pump (3-4) and start the circulation between the user (4-1) and the condenser of the water source heat pump (3-4), so that the heat is delivered to the user (4-1) for heating and domestic hot water; At night, the solar collector (1-1) stops operating, and the circulation of the evaporators of the high-temperature direct supply water tank (3-2), the low-temperature water tank (3-3), and the water source heat pump (3-4) is turned on, as well as the circulation of the condenser of the user (4-1) and the water source heat pump (3-4). The high-temperature direct supply water tank (3-2) and the low-temperature water tank (3-3) provide heat at the same time, and the heat is delivered to the user (4-1) for heating and domestic hot water.

8. A near-zero carbon energy supply method for isolated railway building complexes in solar-rich areas, characterized by: The method is implemented based on the system described in claim 1, and is a combined operation mode of solar thermal cycle and air source heat pump, including: During the day, the solar collector (1-1) receives solar energy. When the solar radiation intensity reaches the set value, the circulation between the solar collector (1-1) and the ethylene glycol-water plate heat exchanger (1-2) is started. At the same time, water is drawn from the low-temperature water tank (3-3) and passed through the ethylene glycol-water plate heat exchanger (1-2). The water after heat exchange is stored in the high-temperature direct supply water tank (3-2). During the daytime, the air source heat pump (3-1) is started to absorb heat from the waste heat recovery unit (2-4) of the photovoltaic back panel of the solar photovoltaic power generation panel (2-1) and start the circulation of the air source heat pump (3-1), the high temperature direct supply water tank (3-2) and the low temperature water tank (3-3); During the day and night, the water source heat pump (3-4) runs continuously, opening the circulation of the high-temperature direct supply water tank (3-2), the low-temperature water tank (3-3) and the evaporator of the water source heat pump (3-4), as well as the circulation of the user (4-1) and the condenser of the water source heat pump (3-4), so that heat is delivered to the user (4-1) for heating and domestic hot water.

9. A near-zero carbon energy supply method for isolated railway building complexes in solar-rich areas, characterized by: The method is implemented based on the system described in claim 1, and is an operation mode of air source heat pump combined with water source heat pump unit and high temperature direct supply water tank, including: During the day and at night, the air source heat pump (3-1) runs continuously, absorbing heat from the outdoor air and starting the circulation of the air source heat pump (3-1), the high-temperature direct supply water tank (3-2), and the low-temperature water tank (3-3); Meanwhile, the water source heat pump (3-4) continues to operate, opening the circulation of the high-temperature direct supply water tank (3-2), the low-temperature water tank (3-3) and the evaporator of the water source heat pump (3-4), as well as the circulation of the user (4-1) and the condenser of the water source heat pump (3-4), and the heat is delivered to the user (4-1) for heating and domestic hot water.

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