Photovoltaic photo-thermal-ground source heat pump coupling system and implementation method thereof

Abstract

The invention discloses a photovoltaic photo-thermal-ground source heat pump coupling system and an implementation method thereof.The photovoltaic photo-thermal-ground source heat pump coupling system comprises a building energy consumption terminal, a PVT system, a ground source heat pump air conditioning system and a hot water supply system, and cooperative work of the photovoltaic photo-thermal-ground source heat pump air conditioning system and the ground source heat pump air conditioning system is achieved by controlling an operation strategy. The implementation method comprises the following steps: S1, establishing a three-dimensional geometric model of a building by using SketchUp; s2, the annual hourly load of the target building is solved through a TRNBuild module, and the heating, refrigeration and domestic hot water requirements of the building are analyzed; the photovoltaic photo-thermal area, the inclination angle, the azimuth angle, the storage battery capacity and the water tank volume serve as main parameters, an objective function is constructed, and the optimal type parameters are obtained through a Hooke-Jeves algorithm; and S3, a TRNSYS simulation platform is adopted to build a photovoltaic photo-thermal-ground source heat pump coupling system, and simulation is carried out for evaluation. By means of the system, efficient utilization of building energy is achieved in different seasons.

Description

Technical Field

[0001] The present invention relates to the technical field of building energy conservation, and in particular to a photovoltaic-thermal-ground source heat pump coupling system and an implementation method thereof. Background Art

[0002] As the proportion of building operation energy consumption continues to rise, photovoltaic power generation, solar thermal collectors and ground source heat pump systems have been widely used in low-rise residential buildings. Photovoltaic power generation systems provide clean renewable electricity to buildings by converting solar energy into electrical energy; solar thermal collectors provide waste heat to buildings by absorbing solar heat. These two technologies are usually applied to building systems in an independent manner, but effective integrated optimization has not yet been achieved. Photovoltaic thermal (PVT) components combine power generation with heat generation functions, which can make full use of the roof resources of low-rise residential buildings, provide electricity and heat energy to buildings at the same time, and increase system energy efficiency.

[0003] At present, low-rise residential buildings in some areas generally adopt traditional energy solutions consisting of air-conditioning systems and gas-fired wall-mounted boilers. This solution relies on fossil energy, has problems such as low energy efficiency and high carbon emissions, and lacks an overall solution that integrates solar energy, electricity and waste heat. On the other hand, the ground source heat pump system extracts or releases soil heat through underground pipes to provide efficient heating and cooling services for buildings. In theory, the combination of photovoltaic thermal systems and ground source heat pumps can further improve energy efficiency, but the existing system usually operates the two separately and lacks an effective coordination mechanism.

[0004] Traditional photovoltaic power generation systems only generate electricity, while solar thermal systems only provide heat. They operate independently of each other, fail to fully utilize building roof resources, and are difficult to achieve multi-energy synergy. Most systems are a single combination of the two. Although PVT components integrate power generation and heat production, they do not integrate solar energy, electricity, and waste heat systems. The ground-source heat pump system extracts soil heat through underground pipes to provide heating and cooling solutions.

[0005] At present, it is still necessary to develop a system architecture that deeply couples photovoltaic thermal energy with ground-source heat pump systems, builds an efficient and coordinated operation and management mechanism, and realizes efficient utilization and optimal allocation of energy. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a photovoltaic thermal-ground source heat pump coupling system and its implementation method, integrating the photovoltaic thermal system with the ground source heat pump system to achieve efficient utilization and optimal allocation of energy, thereby reducing operating costs and carbon emissions and improving the overall energy efficiency of the building.

[0007] Technical solution: A photovoltaic-thermal-ground source heat pump coupling system, including building energy terminals, PVT system, ground source heat pump air conditioning system and hot water supply system. Through the control operation strategy, the photovoltaic PVT system and the ground source heat pump air conditioning system can work together;

[0008] The building energy consumption terminal is a household low-rise residential building, and its parameters mainly include meteorological data, building model, soil temperature, cold and heat load output, and meteorological parameters mainly include dry-bulb and wet-bulb temperature, effective sky radiation, humidity and wind speed;

[0009] The PVT system uses solar energy to supply electricity and waste heat to the building energy terminals, ground source heat pump air conditioning system and hot water supply system;

[0010] The ground source heat pump air conditioning system is mainly responsible for cooling and heating of the building;

[0011] The hot water supply system includes a gas wall-mounted boiler and a hot water tank, which are used to provide hot water for bathing and normal use;

[0012] The operation strategy is divided into cooling season, heating season and transition season, which are as follows:

[0013] Heating season: In the heating part, the PVT system generates electricity and the municipal power grid provides electricity for the ground source heat pump to drive it to heat the building; the waste heat generated by the PVT system is stored in the water tank to provide an auxiliary heat source for the ground source heat pump; the PVT system gives priority to meeting the demand for domestic hot water, and the water tank stores heat to balance the hot water supply; when the solar thermal heat is insufficient, the auxiliary heating equipment gas wall-mounted boiler is started as an auxiliary heating equipment for domestic hot water;

[0014] Cooling season: In the cooling part, the PVT system generates electricity and the municipal power grid provides electricity for the ground source heat pump, driving it to cool the building; the heat of the PVT system is used first to meet the demand for domestic hot water, and the heat is stored in the domestic hot water tank for timely supply; when the solar thermal heat is insufficient, the auxiliary heating equipment gas wall-mounted boiler is used as a supplementary heat source for the hot water system;

[0015] Transition season: The system does not provide heating and cooling, and the heat pump does not start; the PVT system generates electricity mainly for the daily lighting needs of the building, and the excess electricity is stored in the battery for use at other times; the heat of the PVT system is stored in the water tank to meet the hot water supply.

[0016] A method for implementing a photovoltaic-thermal-ground source heat pump coupling system is based on the TRNSYS simulation platform and uses systematic modeling and simulation to analyze the performance and operation effect evaluation of the photovoltaic-thermal-ground source heat pump coupling system; the steps are as follows:

[0017] S1, use SketchUp to build a 3D geometric model of the building;

[0018] S2, solve the hourly load of the target building throughout the year through the TRNBuild module to analyze the building heating, cooling and domestic hot water needs;

[0019] Taking photovoltaic thermal area, inclination angle, azimuth angle, battery capacity and water tank volume as the main parameters, the objective function is constructed, and the Hooke-Jeeves algorithm is used to find the optimal model parameters;

[0020] S3, using the TRNSYS simulation platform to build and simulate the photovoltaic thermal-ground source heat pump coupling system, under the premise that the indoor temperature of the residence meets the design requirements and the hot water load is met, the evaluation objective function reaches the minimum value.

[0021] Further, in step S1, the thermal parameters of the building maintenance structure and the indoor temperature and humidity design standards are imported through the TRNBuild module;

[0022] Divide the internal space of the building into functional areas and mark the cooling and heating load requirements of each area; divide the air-conditioned area rooms into bedrooms, living rooms, and living rooms, and mark the energy requirements and operating characteristics of different areas.

[0023] Further, in step S2, meteorological data of the selected area is retrieved through meteorological database software, including temperature, humidity, sunshine, wind speed and solar radiation;

[0024] Set design parameters for heating and cooling seasons, including occupancy rates, lighting schedules, hot water demand schedules, and indoor design temperatures, to calculate hour-by-hour building heating and cooling load distribution throughout the year.

[0025] Furthermore, the objective function includes the following indicators:

[0026] Economic evaluation:

[0027] Z=C c +C f +C m

[0028] In the formula, Z is the annual cost of the system, C c is the annual value of the investment in various equipment of the system, RMB; C f is the annual operating cost of the system, RMB; C m is the annual maintenance cost of the system, RMB;

[0029]

[0030] In the formula, i is the annual loan interest rate; n is the system operation period; L 0 is the total equipment investment cost, yuan;

[0031] L 0=A pvt S pvt +A soc S soc +V tank S tank +C e

[0032] In the formula, A pvt is the photovoltaic thermal area, m 2 ; S pvt The photovoltaic thermal price per unit area is RMB / m 2 ; A soc is the battery capacity, kWh; S soc Price per unit battery capacity, yuan / kWh; V tank is the volume of the water tank, m 3 ; S tank Water tank price, yuan / m 3 ; C e Investment costs for other fixed equipment;

[0033] Photovoltaic thermal power generation, including the system's own consumption and the income from accessing the grid, is calculated as follows:

[0034] P pvt =η pvt A pvt G

[0035] Where P pvt is photovoltaic thermal power generation, kWh; η pvt is the photovoltaic thermal power generation efficiency; G is the photovoltaic thermal surface solar radiation intensity, MJ / m 2 ;

[0036] The photovoltaic thermal energy collected, including the amount of water tank heating and water tank hot water supply, is calculated as follows:

[0037] Q pvt =η S A pvt G

[0038] In the formula, Q pvt is the photovoltaic thermal energy collection amount, kWh; η s is the photovoltaic thermal collection efficiency;

[0039] C f =c g p g +c p p p -c s p s

[0040] In the formula, c g Natural gas unit price, yuan / m 3;p g Annual natural gas consumption, m 3 ;c p Municipal electricity purchase price, yuan / kWh; p p Municipal electricity consumption, kWh; c s On-grid electricity price, yuan / kWh; p s Online electricity, kWh;

[0041] C m =aL 0

[0042] In the formula, a is the maintenance coefficient ratio;

[0043] Environmental assessment:

[0044]

[0045] Where M co2 is the annual carbon dioxide emissions of the system, kgCO 2 ;p r is the annual operating natural gas heat of the system, Tj; b e Carbon dioxide emission factor for natural gas, kgCO 2 / TJ;b g is the carbon dioxide emission factor for electricity, kgco 2 / kWh;

[0046] Therefore, the objective function of comprehensive multi-objective optimization is as follows:

[0047]

[0048] In the formula, F is the objective function; ω is the weight factor; Z 0 is the annual value of the benchmark system cost; M 0 CO2 is the annual operating carbon dioxide emissions of the benchmark system; the benchmark system is a ground source heat pump system without PVT coupling.

[0049] Compared with the prior art, the present invention has the following significant effects:

[0050] 1. Design of low-rise residential buildings in hot summer and cold winter areas that require cooling, heating and domestic hot water. The system design of the present invention uses a gas wall-mounted boiler as an auxiliary heating device to solve the problem of unstable solar heating throughout the year. A specific and detailed design scheme and specific operation strategy are designed according to the specific building.

[0051] 2. The system of the present invention takes into account the two major energy consumption parts of low-rise residential buildings: air conditioning and hot water. It takes into account a comprehensive approach, adds a gas-fired wall-mounted boiler hot water supply device that is more common in hot summer and cold winter areas, and couples the energy supply of multiple components of the PVT and ground source heat pump air conditioning system to achieve the coordinated and optimized utilization of electrical energy and thermal energy; comprehensively utilizes multiple energy sources, fully utilizes solar energy resources, gives full play to the advantages of power generation, solar thermal utilization and underground pipe heat exchange in PVT, and uses natural gas as an auxiliary method to meet the annual energy consumption needs of household-type low-rise residential buildings, as well as the stability of solar energy utilization;

[0052] 3. The method of the present invention sets seasonal operation throughout the year, which is divided into cooling season, heating season and transition season operation strategies. By dynamically coordinating the supply and adjusting the priority of heating, cooling and domestic hot water supply, the system of the present invention realizes efficient utilization of building energy in different seasons, reduces traditional energy consumption and carbon emissions, and effectively arranges energy utilization methods;

[0053] 4. In the method of the present invention, after the application scenario is fixed, a multi-objective optimization model is set up, and economic functions and environmental functions are used to optimize PVT area, inclination, azimuth, water tank volume, battery capacity and other parameters to improve the power generation efficiency of PVT. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is the schematic diagram of the photovoltaic thermal-ground source heat pump coupling system;

[0055] Figure 2 This is the connection details diagram of the photovoltaic thermal-ground source heat pump coupling system;

[0056] Figure 3 This is a flow chart of the implementation process of the photovoltaic thermal-ground source heat pump coupling system;

[0057] Figure 4 Multi-objective optimization simulation flow chart;

[0058] Figure 5 Flowchart of the calculation steps for the Hooke-Jeeves algorithm. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0060] like Figure 1 , Figure 2As shown, the photovoltaic thermal-ground source heat pump coupling system of the present invention mainly includes the following four subsystems: building energy terminal, photovoltaic thermal (PVT) system, ground source heat pump air conditioning system and hot water supply system. By controlling the operation strategy, the coordinated work of the photovoltaic thermal (PVT) system and the ground source heat pump air conditioning system is realized. The photovoltaic components in the PVT system collect solar energy and convert it into electrical energy to drive the operation of the ground source heat pump, and store the excess heat energy in the hot water storage tank. The general benchmark system is composed of a ground source heat pump air conditioning system and a hot water supply system that operate independently of each other. After coupling it with photovoltaic thermal (PVT), by setting up a hot water storage tank, the photovoltaic thermal (PVT) is coordinated with the ground source heat pump and hot water supply respectively. This system approach improves energy utilization efficiency and reduces the consumption of traditional energy. Secondly, the carbon emissions of the building are significantly reduced during the operation of the coupling system, which helps to achieve the goal of sustainable development.

[0061] The building energy consumption terminal is a household low-rise residential building. Its parameters mainly include meteorological data, building model, soil temperature, cold and heat load output. Meteorological parameters mainly include dry and wet bulb temperature, effective sky radiation, humidity, wind speed, etc. In this embodiment, a household low-rise residential building in Nanjing is used as an example, and a family of seven is set. Sketchup is used for three-dimensional modeling, and Trnbuild is used to set HVAC parameters to solve the cold and heat loads; among them, the building model is a model established according to the building drawings, and TRNbuild software is used to set the meteorological parameters. TRNSYS runs the low-rise residential load to perform the building model.

[0062] The photovoltaic thermal (PVT) system includes meteorological data, photovoltaic thermal (PVT), inverter, battery, heat pump, first diverter, and water tank. It is mainly used to make full use of solar energy to supply electricity and waste heat to other systems (building energy terminals, ground source heat pump air conditioning system and hot water supply system).

[0063] The ground source heat pump air conditioning system includes: heat pump, buried pipe, second diverter, ground source side water pump, load side water pump, fan coil unit and lighting power system, which is mainly responsible for the cooling and heating part of the building.

[0064] The hot water supply system includes: a gas wall-mounted boiler and a hot water tank, which are used to provide bathing and normal hot water supply.

[0065] The operation strategies of the photovoltaic-ground source heat pump coupling system are divided into cooling season, heating season and transition season, as follows:

[0066] Heating season (November 15 to March 31): For heating, the photovoltaic solar thermal (PVT) system generates electricity and the municipal power grid to provide electricity for the ground source heat pump, which drives it to heat the building. The waste heat generated by the solar thermal part of the PVT system is stored in the water tank to provide an auxiliary heat source for the ground source heat pump, further improving the energy efficiency of the system. For the domestic hot water supply, the PVT system gives priority to meeting the demand for domestic hot water, and the water tank stores heat to balance the hot water supply. When the solar thermal heat is insufficient, the auxiliary heating equipment, the gas wall-mounted boiler, is started as an auxiliary heating equipment for domestic hot water.

[0067] Cooling season (April 15 to October 15): For cooling, the PVT system generates electricity and the municipal power grid to provide electricity for the ground source heat pump, driving it to cool the building. For domestic hot water supply, the heat from the solar thermal part of the PVT system is used first to meet the domestic hot water demand, and the heat is stored in the domestic hot water tank for timely supply. When the solar thermal heat is insufficient, the auxiliary heating equipment gas wall-mounted boiler serves as a supplementary heat source for the hot water system.

[0068] Transition season (rest of the year): The system does not provide heating and cooling, and the heat pump does not start. The power generated by the PVT system is mainly used for the daily lighting power demand of the building. The excess power is stored in the battery for use at other times, and the surplus power is connected to the grid to generate income. The heat of the solar thermal part of the PVT system is stored in the water tank to meet the hot water supply.

[0069] By dynamically coordinating and adjusting the priorities of heating, cooling and domestic hot water supply, the photovoltaic thermal-ground source heat pump coupling system of the present invention achieves efficient utilization of building energy in different seasons, reducing traditional energy consumption and carbon emissions.

[0070] The photovoltaic thermal-ground source heat pump coupling system implementation method of the present invention is based on the TRNSYS simulation platform. Figure 3 As shown, systematic modeling and simulation are used to comprehensively analyze system performance and evaluate operating effects. The specific steps include:

[0071] Step 1, constructing a building model;

[0072] In order to accurately reflect the building physical characteristics and operating environment of the research object, SketchUp is first used to establish a three-dimensional geometric model of the building. By simulating the physical characteristics of the building such as shape, spatial layout and orientation, the foundation is laid for subsequent simulation analysis.

[0073] Building physical parameter setting, through the TRNBuild module, import the thermal parameters of the building maintenance structure (wall heat transfer coefficient, window material, window frame ratio, etc.) and indoor temperature and humidity design standards to ensure that the simulation model accurately reflects the actual energy consumption characteristics of the building.

[0074] Functional zoning and load definition: divide the internal space of the building into functional areas, mark the cooling and heating load requirements of each area, and provide a basis for the design of system operation strategies. Divide the air-conditioned area into bedrooms, living rooms (living rooms, etc.), and mark the energy requirements and operation characteristics of different areas.

[0075] Step 2, load solution;

[0076] The TRNBuild module is used to solve the hourly load of the target building throughout the year and analyze the building's heating, cooling and domestic hot water needs.

[0077] Meteorological data import: The meteorological data of the selected area is retrieved through the meteorological database software Meteonorm (TMY), including parameters such as temperature, humidity, sunshine, wind speed and solar radiation, as simulated weather input conditions.

[0078] Load calculation, set the design parameters of the heating and cooling seasons, such as occupancy rate, lighting schedule, hot water demand schedule, indoor design temperature, etc., to calculate the building's annual cooling and heating load distribution hour by hour. TRNSYS calculates the annual cooling and heating loads based on the maintenance structure settings after house modeling, indoor temperature design (18 degrees in winter, 26 degrees in summer), etc., to match the system's terminal energy consumption. The implementation method is software simulation calculation.

[0079] A 3D house model was built through Sketchup, air conditioning parameters were set through TRNBuild, and TRNSYS software was used to simulate and run for 8760 hours throughout the year to solve the cooling and heating loads.

[0080] Result analysis: A low-rise residential load model is established in TRNSYS. The peak load and total seasonal load are analyzed through simulation results to provide data basis for subsequent equipment selection and system capacity configuration.

[0081] In the photovoltaic thermal-ground source heat pump coupling system of the present invention, equipment parameters such as the area, inclination, azimuth, battery capacity and water tank volume of the photovoltaic thermal system have a significant impact on the system performance, economic cost and carbon emissions during the operation stage. The photovoltaic thermal area, under ideal conditions without considering the investment cost and the requirements of specific application scenarios, the larger the area, the more power generation and heat collection, and the effective utilization rate of solar energy will also increase accordingly. However, when the area exceeds a certain threshold, the building heat terminal cannot consume too much heat in time, which will cause the photovoltaic thermal temperature to rise, thereby reducing the efficiency of photovoltaic power generation and causing waste of resources. Therefore, in a specific application scenario, there must be an optimal photovoltaic thermal area. After optimization, the annual cost value and carbon emissions are minimized; the inclination and azimuth directly determine the intensity of solar radiation received by the PVT surface. Different application scenarios vary due to factors such as geographical latitude and surrounding environment, and there are optimal inclination and azimuth that are adapted to them. The optimal values ​​of inclination and azimuth can maximize the intensity of solar radiation received by the surface, reduce the cost and carbon emissions caused by the additional consumption of other energy sources due to insufficient radiation, and thus improve the overall economic and environmental benefits of the system. After optimization, the annual cost value and carbon emissions are minimized; the battery plays the role of power regulation in the system. When the power generation exceeds the load, the excess power is stored, and the excess power will be subsequently incorporated into the power grid. When the load demand is greater than the power generation, the battery is discharged first to supply the load. As the battery capacity increases, the amount of electricity that can be stored increases, which can provide more electricity for the power load, reduce the amount of electricity purchased from the municipal power grid, and reduce the cost of purchasing electricity. However, if the other equipment parameters are fixed and the application scenario is determined, the increase in battery capacity reduces the revenue from selling electricity to the power grid, but reduces the cost of purchasing electricity. At the same time, the increase in battery capacity means higher investment costs. When the battery capacity exceeds the optimal value, the increase in investment costs may exceed the savings in electricity purchase costs, resulting in a decrease in the economy of the system. Therefore, it is necessary to optimize the system to minimize the annual cost and carbon emissions; the volume of the water tank also affects the performance, economy and environmental benefits of the system. The larger the volume of the water tank, the more heat it can store, which increases the heat storage capacity and helps stabilize the heating capacity of the system. Under the condition of a certain photovoltaic thermal area, if the volume of the water tank is too large and exceeds the effective heating range of the collector, it will not only increase the investment cost, but also fail to achieve the goal of energy saving and carbon reduction, because the additional investment does not bring about improved energy efficiency and reduced carbon emissions. Therefore, it is important to reasonably determine the volume of the water tank. Therefore, it is necessary to optimize the system to minimize the annual cost and carbon emissions.

[0082] Some other equipment is selected based on multi-objective function optimization. Parameters such as photovoltaic thermal area, inclination, azimuth, battery capacity, water tank volume, etc. are selected by using the algorithm of Genopt software. Figure 4As shown. In particular, the equations for solving conventional collectors are not accurate enough for collectors and need to be obtained under the dynamic optimization of the objective function. Photovoltaic thermal power generation can save electricity, reduce the amount of heat pumps, and reduce the amount of gas consumed by gas-fired wall-mounted boilers.

[0083] The objective function includes the following indicators:

[0084] Economic evaluation:

[0085] Z=C c +C f +C m (1)

[0086] Where: Z is the annual cost of the system, C c is the annual value of the investment in various equipment of the system, RMB; C f is the annual operating cost of the system, RMB; C m is the annual maintenance cost of the system, Yuan.

[0087]

[0088] Where: i is the annual loan interest rate, which is 0.05; n is the system operation period, which is 20 years; L 0 is the total equipment investment cost, Yuan.

[0089] L 0 =A pvt S pvt +A soc S soc +V tank S tank +C e (3)

[0090] Where: A pvt is the photovoltaic thermal area, m 2 ; S pvt The photovoltaic thermal price per unit area is RMB / m 2 ; A soc is the battery capacity, kWh; S soc Price per unit battery capacity, yuan / kWh; V tank is the volume of the water tank, m 3 ; S tank Water tank price, yuan / m 3 ; C e Investment costs for other fixed equipment.

[0091] Photovoltaic thermal power generation includes two parts: one part is consumed by the system itself, and the other part is connected to the grid to obtain income. The calculation formula is:

[0092] P pvt =η pvt A pvtG (4)

[0093] Where: P pvt is photovoltaic thermal power generation, kWh; η pvt is the photovoltaic thermal power generation efficiency; G is the photovoltaic thermal surface solar radiation intensity, MJ / m 2 ;

[0094] The photovoltaic thermal energy collected includes two parts, one for water tank heating and the other for water tank hot water supply. The calculation formula is:

[0095] Q pvt =η S A pvt G (5)

[0096] Where: Q pvt is the photovoltaic thermal energy collection amount, kWh; η s is the photovoltaic thermal collection efficiency.

[0097] C f =c g p g +c p p p -c s p s (6)

[0098] Where: c g Natural gas unit price, yuan / m 3 ;p g Annual natural gas consumption, m 3 ;c p Municipal electricity purchase price, yuan / kWh; p p Municipal electricity consumption, kWh; c s On-grid electricity price, yuan / kWh; p s Online electricity consumption, kWh.

[0099] C m =aL 0 (7)

[0100] Where: a is the maintenance coefficient ratio, which is 0.01.

[0101] Environmental assessment:

[0102]

[0103] Where M co2 is the annual carbon dioxide emissions of the system, kgCO 2 ;p r is the annual natural gas heat of the system, TJ; b e Carbon dioxide emission factor for natural gas, kgCO 2 / TJ;bg is the carbon dioxide emission factor for electricity, kgco 2 / kWh.

[0104] The objective function of comprehensive multi-objective optimization is as follows:

[0105]

[0106] Where: F is the objective function; ω is the weight factor; Z 0 is the annual cost of the benchmark system (ground source heat pump system without PVT coupling); M 0 CO2 is the annual carbon dioxide emissions of the benchmark system (ground source heat pump system without PVT coupling).

[0107] With the dual factors of economic evaluation and environmental evaluation, Genopt uses multi-objective functions to optimize the selection parameters of some equipment to achieve optimal performance. Genopt calls the Hooke-Jeeves algorithm, inputs the optimization variables photovoltaic thermal area Apvt, battery capacity Asoc, water tank volume Vtank, photovoltaic thermal inclination angle Slope, photovoltaic thermal azimuth, and sets the algorithm parameters as initial step size δ, acceleration factor α≥1, reduction rate β∈(0,1), and allowable error ε>0. The calculation step flow chart is as follows Figure 5 shown.

[0108] Step 3: Build the system and perform simulation;

[0109] The photovoltaic thermal-ground source heat pump coupling system is built using the TRNSYS simulation platform, which includes the following sub-modules: low-rise residential building energy terminal module, photovoltaic thermal (PVT) heating and power supply module, ground source heat pump air conditioning module, and hot water supply module.

[0110] The energy terminal module for low-rise residential buildings has been established in the load solution link, mainly including Type 56 building components, Type 77 ground temperature input components, and Type 15-2 weather components.

[0111] Photovoltaic thermal (PVT) heating and power supply module imports PVT performance parameters (such as power generation efficiency and heat collection efficiency, etc.), combines the building roof area and sunshine conditions, and calculates photovoltaic power and heat output. It mainly includes Type15-2 weather components, Type48b inverter components, Type50bPVT components, Type114 heat collection pump components, Type156 water tanks, and Type47a battery components.

[0112] The ground source heat pump air conditioning module sets the performance parameters of the underground pipe heat exchanger and the heat pump unit, simulates the water flow circulation on the source side and the load side of the heat pump, and the energy conversion and distribution process. It mainly includes Type 927 heat pump components, Type 557a underground pipe components, Type 146 fan components, Type 753e coil components, Type 156 water tank components, Type 114 load side water pump components and Type 114 ground source side water pump components.

[0113] The hot water supply module meets the dynamic demand for domestic hot water in buildings through auxiliary heating equipment, gas wall-mounted boilers and water storage tanks. It mainly includes Type 659 gas wall-mounted boiler components and Type 156 water tank components.

[0114] Based on the TRNSYS platform, the coupling system is dynamically simulated and analyzed to evaluate its comprehensive performance and operation effect throughout the year. Under the premise that the indoor temperature of the residence meets the design requirements and the hot water load is satisfied, the evaluation objective function reaches the minimum value. The whole year is set to 8760 hours, with a simulation step of 0.125 hours, and the operation results of the photovoltaic-ground source heat pump coupling system under the meteorological conditions and load levels in Nanjing, Jiangsu Province are analyzed, including PVT power generation, heat collection, and performance coefficient (COP) of the ground source heat pump.

[0115] In summary, the modeling and simulation research based on TRNSYS provides a scientific basis for the design, optimization and promotion and application of the system of the present invention, and significantly improves the operability and analyzability of the system.

Claims

1. A photovoltaic-thermal-ground source heat pump coupling system, characterized in that: Including building energy terminals, PVT system, ground source heat pump air conditioning system and hot water supply system, through the control operation strategy, the light PVT system and ground source heat pump air conditioning system can work together; The building energy consumption terminal is a household low-rise residential building, and its parameters mainly include meteorological data, building model, soil temperature, cold and heat load output, and meteorological parameters mainly include dry-bulb and wet-bulb temperature, effective sky radiation, humidity and wind speed; The PVT system uses solar energy to supply electricity and waste heat to the building energy terminals, ground source heat pump air conditioning system and hot water supply system; The ground source heat pump air conditioning system is mainly responsible for cooling and heating of the building; The hot water supply system includes a gas wall-mounted boiler and a hot water tank, which are used to provide hot water for bathing and normal use; The operation strategy is divided into cooling season, heating season and transition season, which are as follows: Heating season: In the heating part, the PVT system generates electricity and the municipal power grid provides electricity for the ground source heat pump to drive it to heat the building; the waste heat generated by the PVT system is stored in the water tank to provide an auxiliary heat source for the ground source heat pump; the PVT system gives priority to meeting the demand for domestic hot water, and the water tank stores heat to balance the hot water supply; when the solar thermal heat is insufficient, the auxiliary heating equipment gas wall-mounted boiler is started as an auxiliary heating equipment for domestic hot water; Cooling season: In the cooling part, the PVT system generates electricity and the municipal power grid provides electricity for the ground source heat pump, driving it to cool the building; the heat of the PVT system is used first to meet the demand for domestic hot water, and the heat is stored in the domestic hot water tank for timely supply; when the solar thermal heat is insufficient, the auxiliary heating equipment gas wall-mounted boiler is used as a supplementary heat source for the hot water system; Transition season: The system does not provide heating and cooling, and the heat pump does not start; the PVT system generates electricity mainly for the daily lighting needs of the building, and the excess electricity is stored in the battery for use at other times; the heat of the PVT system is stored in the water tank to meet the hot water supply.

2. A method for implementing a photovoltaic-thermal-ground source heat pump coupling system, based on the TRNSYS simulation platform, using systematic modeling and simulation to analyze the performance and operation effect evaluation of the photovoltaic-thermal-ground source heat pump coupling system as claimed in claim 1; characterized in that: The steps include: S1, use SketchUp to build a 3D geometric model of the building; S2, solve the hourly load of the target building throughout the year through the TRNBuild module to analyze the building heating, cooling and domestic hot water needs; Taking photovoltaic thermal area, inclination angle, azimuth angle, battery capacity and water tank volume as the main parameters, the objective function is constructed, and the Hooke-Jeeves algorithm is used to find the optimal model parameters; S3, using the TRNSYS simulation platform to build and simulate the photovoltaic thermal-ground source heat pump coupling system, under the premise that the indoor temperature of the residence meets the design requirements and the hot water load is met, the evaluation objective function reaches the minimum value.

3. The method for implementing the photovoltaic-geothermal heat pump coupling system according to claim 2, characterized in that: In step S1, the thermal parameters of the building maintenance structure and the indoor temperature and humidity design standards are imported through the TRNBuild module; Divide the internal space of the building into functional areas and mark the cooling and heating load requirements of each area; divide the air-conditioned area rooms into bedrooms and living rooms, and mark the energy requirements and operating characteristics of different areas.

4. The method for implementing the photovoltaic-ground source heat pump coupling system according to claim 2 is characterized in that: In step S2, meteorological data of the selected area is retrieved through meteorological database software, including temperature, humidity, sunshine, wind speed and solar radiation; Set design parameters for heating and cooling seasons, including occupancy rates, lighting schedules, hot water demand schedules, and indoor design temperatures, to calculate hour-by-hour building heating and cooling load distribution throughout the year.

5. The method for implementing the photovoltaic-geothermal heat pump coupling system according to claim 2, characterized in that: The objective function includes the following indicators: Economic evaluation: Z=C c +C f +C m In the formula, Z is the annual cost of the system, C c is the annual value of the investment in various equipment of the system, RMB; C f is the annual operating cost of the system, RMB; C m is the annual maintenance cost of the system, RMB; In the formula, i is the annual loan interest rate; n is the system operation period; L0 is the total equipment investment cost, yuan; L0=A pvt With pvt +A soc With soc +V tank With tank +C e In the formula, A pvt is the photovoltaic thermal area, m 2 ; S pvt The photovoltaic thermal price per unit area is RMB / m 2 ; A soc is the battery capacity, kWh; S soc Price per unit battery capacity, RMB / kWh; V tank is the volume of the water tank, m 3 ; S tank Water tank price, yuan / m 3 ; C e Investment costs for other fixed equipment; Photovoltaic thermal power generation, including the system's own consumption and the income from access to the Internet, is calculated as follows: P pvt =the pvt A pvt G Where P pvt is photovoltaic thermal power generation, kWh; η pvt is the photovoltaic thermal power generation efficiency; G is the photovoltaic thermal surface solar radiation intensity, MJ / m 2 ; The photovoltaic thermal energy collected includes the amount of water tank heating and water tank hot water supply. The calculation formula is: Q pvt =the S A pvt G In the formula, Q pvt is the photovoltaic thermal energy collection amount, kWh; η s is the photovoltaic thermal collection efficiency; C f =c g p g +c p p p -c s p s In the formula, c g Natural gas unit price, yuan / m 3 ; p g Annual natural gas consumption, m 3 ; c p Municipal electricity purchase price, yuan / kWh; p p Municipal electricity consumption, kWh; c s On-grid electricity price, yuan / kWh; p s Online electricity, kWh; C m =aL0 In the formula, a is the maintenance factor ratio; Environmental assessment: M co2 =p r b e +(p g -p s )b g Where M co2 is the annual carbon dioxide emission of the system, kgCO2; p r is the annual natural gas heat of the system, Tj; b e Carbon dioxide emission factor of natural gas, kgCO2 / TJ; b g is the CO2 emission factor for electricity, kgco2 / kWh; Therefore, the objective function of comprehensive multi-objective optimization is as follows: In the formula, F is the objective function; ω is the weight factor; Z 0 is the annual value of the benchmark system cost; M 0 CO2 is the annual operating carbon dioxide emissions of the benchmark system; The benchmark system is a ground source heat pump system without PVT coupling.

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