Heating method, device and system combining solar heat storage and building transformation

Abstract

The invention relates to the technical field of heat energy storage and heating, and provides a heating method, device and system combining solar heat storage and building renovation, and the method comprises the steps that a heat storage wall is arranged in a building outer wall structure, and building thermal inertia is enhanced to reduce heating loads; heat is collected in the daytime through the solar heat collection unit and stored in the phase change heat storage unit preferentially, and energy distribution is controlled based on a heat conduction oil temperature threshold value; on the basis of a night time-of-use electricity price strategy, heat is supplemented to the phase change heat storage unit through the heating unit in the off-peak period, and the heat storage temperature is maintained to be not lower than 40 DEG C; a heating loop is dynamically adjusted through a multi-loop temperature control unit, when the indoor temperature of a building is lower than 20 DEG C, phase change latent heat is released preferentially, and when sensible heat storage is insufficient, a heating unit is triggered to supply heat in an auxiliary mode; the solar energy utilization rate is increased, the indoor heating time is prolonged, more stable energy supply, higher solar energy proportion and lower operation cost are provided, and the solar heat storage system has wide application prospects in heat storage systems of small residences.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal energy storage heating, and in particular to a heating method, device and system combining solar energy heat storage with building renovation. Background Art

[0002] As the impact of global warming intensifies worldwide, reducing carbon emissions requires a concerted effort from all countries. Extreme weather events caused by climate change have exposed the vulnerability of global heating and cooling infrastructure. Increased energy consumption has led to energy shortages and exacerbated environmental pollution, making it one of the world's most pressing challenges. According to statistics, heating accounts for over 75% of final energy consumption in the building and industrial sectors. Therefore, improving the energy efficiency of building heating systems is crucial to achieving carbon peak and neutrality goals. To address the energy conservation challenges faced by buildings, many scholars have proposed energy-efficient designs through various research methods. These can be broadly categorized into the following areas: optimizing building materials, passive building design, and more. While these studies can reduce building energy consumption to a certain extent, extensive experiments are still required to demonstrate the effectiveness and cost-effectiveness of the materials used, as well as the effectiveness of fully passive buildings.

[0003] The drawbacks of solar energy are its instability and volatility. Using thermal storage systems is one of the keys to economically and stably utilizing solar energy. Building design modifications are also a key approach to reducing building carbon emissions. Existing research has primarily analyzed materials, local modifications, and design strategies, making significant progress and promising results. However, this relatively narrow focus, lacking the integration of diverse solar energy utilization methods, has limited its impact on reducing indoor heating consumption.

[0004] Therefore, how to combine passive heating and solar heat storage for winter heating of houses, solve the efficiency loss problem of traditional heat storage systems, improve solar energy utilization, extend indoor heating time, and come up with a full life cycle cost optimization plan has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] In view of this, the main purpose of the present invention is to provide a heating method, device and system that combines solar heat storage with building renovation, aiming to solve the efficiency loss problem of traditional heat storage systems, improve the utilization rate of solar energy, extend the indoor heating time, and obtain a full life cycle cost optimization solution.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a heating method combining solar thermal storage with building renovation, comprising the following steps: S1, setting a heat storage wall in the building exterior wall structure to enhance the thermal inertia of the building to reduce the heating load; S2, collecting heat during the day through a solar thermal collection unit, preferentially storing it in a phase change thermal storage unit, and controlling energy distribution based on the thermal oil temperature threshold; S3, based on a night-time time-of-use electricity price strategy, supplementing heat to the phase change thermal storage unit during off-peak hours through a heating unit to maintain a heat storage temperature of not less than 40°C; S4, dynamically adjusting the heating circuit through a multi-circuit temperature control unit, preferentially releasing the phase change latent heat when the indoor temperature of the building is lower than 20°C, and triggering the heating unit to assist in heating when the sensible heat reserve is insufficient; S5, coupling the GenOpt algorithm with the TRNSYS dynamic simulation algorithm, optimizing the parameters of the solar thermal collection unit and / or the phase change thermal storage unit through the Hooke-Jeeves search method, and outputting a full life cycle cost minimization strategy.

[0007] In the second aspect, the present invention provides a heating device that combines solar heat storage and building renovation, including: a heat storage wall, which is arranged at the building unit; a solar heat collection unit, in which heat transfer oil is provided; a phase change heat storage unit, which is connected to the solar heat collection unit and is used to collect heat from the solar heat collection unit and heat the building unit; a heating unit, which is connected to the phase change heat storage unit through a multi-circuit temperature control unit, and is used to supplement heat during non-peak hours at night and when the sensible heat reserve is insufficient; a multi-circuit temperature control unit, which is respectively connected to the heating unit and the phase change heat storage unit, and is used to switch the heating mode according to the temperature and time-of-use electricity price strategy.

[0008] In a third aspect, the present invention provides a heating system combining solar thermal storage and building renovation, comprising: the heating device combining solar thermal storage and building renovation disclosed in the second aspect above; a TRNSYS dynamic simulation module for constructing a building heat load model and a heating system comparative analysis model; a time-of-use electricity price response module for controlling the start and stop of the heating unit and the heating and heat release of the phase change heat storage unit according to the electricity price period, maintaining the heat storage temperature at not less than 40°C; a PID dynamic adjustment module for releasing phase change latent heat and triggering auxiliary heating of the heating unit according to the indoor temperature and sensible heat reserve; a GenOpt cost optimization module for optimizing the parameters of the solar thermal collection unit and / or the phase change heat storage unit to obtain a full life cycle cost minimization strategy.

[0009] In a fourth aspect, the present invention provides an electronic device comprising a memory and a processor, wherein: the memory is used to store a computer program; and the processor is used to execute the computer program to implement the heating method combining solar heat storage and building renovation as disclosed in the third aspect.

[0010] In a fifth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program is used to be executed by a processor to implement the heating method combining solar thermal storage and building renovation as disclosed in the third aspect.

[0011] The technical solution provided by this invention reduces winter heating costs by transforming traditional houses into low-carbon buildings and combining them with solar thermal storage and heating. This approach raises indoor temperatures by increasing indoor solar radiation, and utilizes the thermal insulation properties of thermal storage materials and thermal storage tanks to store solar energy, thereby improving solar energy utilization and extending indoor heating time. A multi-loop dynamic coupling simulation model was constructed based on the TRNSYS platform, employing a time-sharing and zoning control strategy to effectively address the efficiency losses of traditional thermal storage systems. Compared to traditional systems, the technical solution proposed in this application demonstrates a more stable energy supply, a higher solar energy share, and reduced operating costs, and has broad application prospects in thermal storage systems for small homes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] One or more embodiments are exemplarily illustrated by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0013] Figure 1 A room plan of a building unit disclosed in an embodiment of the present application;

[0014] Figure 2 A three-dimensional plan view of a building unit disclosed in an embodiment of the present application;

[0015] Figure 3 Schematic diagram of the TRNSYS dynamic simulation process disclosed in the embodiment of this application;

[0016] Figure 4 This is a schematic diagram of monthly heat load comparison disclosed in the embodiments of this application;

[0017] Figure 5 A schematic diagram of the system disclosed in the embodiment of this application;

[0018] Figure 6 A schematic diagram of the TRNSYS system modeling disclosed in the embodiments of the present application;

[0019] Figure 7 This is a schematic diagram of the simulation workflow disclosed in the embodiments of this application;

[0020] Figure 8 This is a schematic diagram of the supply and return water temperature and outdoor temperature disclosed in the embodiment of this application;

[0021] Figure 9A schematic diagram of energy and temperature changes in a heat storage tank disclosed in an embodiment of the present application;

[0022] Figure 10 This is a schematic diagram of the temperature from January 11 to 13 disclosed in the embodiments of this application;

[0023] Figure 11 This is a schematic diagram of the water tank change analysis disclosed in the embodiment of this application;

[0024] Figure 12 This is a schematic diagram of energy analysis of the heat storage tank disclosed in the embodiment of this application;

[0025] Figure 13 This is a schematic diagram of temperature changes under different weather conditions disclosed in the embodiments of this application;

[0026] Figure 14 This is a schematic diagram of the power consumption of the pump disclosed in the embodiment of this application;

[0027] Figure 15 A schematic diagram of the system operating costs disclosed in the embodiments of this application;

[0028] Figure 16 This is a schematic diagram of the thickness variation of the thermal storage wall disclosed in the embodiment of this application;

[0029] Figure 17 A schematic diagram of the operating costs of the system 2 disclosed in the embodiment of this application;

[0030] Figure 18 Schematic diagram of the heat release and heat storage process of the system 2 disclosed in the embodiment of the present application;

[0031] Figure 19 Schematic diagram of modeling of the system 3TRNSYS disclosed in the embodiment of the present application;

[0032] Figure 20 This is a schematic diagram of the operating costs of the system 3 disclosed in the embodiment of the present application;

[0033] Figure 21 This is a schematic diagram of energy analysis of system 2 disclosed in an embodiment of the present application;

[0034] Figure 22 This is a schematic diagram of energy analysis of the system 1 disclosed in the embodiment of the present application;

[0035] Figure 23 This is a schematic diagram of the Genopt optimization process disclosed in the examples of this application;

[0036] Figure 24 This is a schematic diagram of the influence of the collector area disclosed in the embodiment of this application;

[0037] Figure 25A schematic diagram of the accumulated operating costs disclosed in the embodiments of this application;

[0038] Figure 26 This is a schematic diagram of the heat collection and storage disclosed in the embodiments of this application;

[0039] Figure 27 A schematic diagram showing a comparison of power consumption disclosed in the embodiments of this application;

[0040] Figure 28 A schematic diagram of comparative analysis of system optimization disclosed in the embodiments of this application;

[0041] Figure 29 A cash flow diagram of the proposed system disclosed in the embodiment of this application;

[0042] Figure 30 This is a flow chart of a heating method combining solar thermal storage and building renovation disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0043] To facilitate understanding of the present invention, the present invention is described in more detail below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly attached to the other element, or one or more elements can be interposed therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more elements can be interposed therebetween. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and similar expressions used in this specification are for illustrative purposes only. In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or implicitly specifying the number of technical features indicated. Therefore, unless otherwise specified, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; "plurality" means two or more. The term "comprising" and any variations thereof are intended to be non-exclusive, and one or more other features, integers, steps, operations, units, components, and / or combinations thereof may be present or added.

[0044] In addition, unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or internal communication between two components. All technical and scientific terms used in this specification have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0045] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Example 1: To achieve the above-mentioned objectives, an embodiment of the present invention provides a heating method combining solar thermal storage with building renovation, comprising the following steps: S1, setting a heat storage wall in the building's exterior wall structure to enhance the building's thermal inertia to reduce the heating load; S2, collecting heat during the day through a solar thermal collection unit, preferentially storing it in a phase change thermal storage unit, and controlling energy distribution based on the thermal oil temperature threshold; S3, based on a night-time time-of-use electricity price strategy, supplementing heat to the phase change thermal storage unit during off-peak hours through a heating unit to maintain a heat storage temperature of not less than 40°C; S4, dynamically adjusting the heating circuit through a multi-circuit temperature control unit, preferentially releasing the phase change latent heat when the indoor temperature of the building is below 20°C, and triggering the heating unit to assist in heating when the sensible heat reserve is insufficient; S5, coupling the GenOpt algorithm with the TRNSYS dynamic simulation algorithm, optimizing the parameters of the solar thermal collection unit and / or the phase change thermal storage unit through the Hooke-Jeeves search method, and outputting a full life cycle cost minimization strategy. In some embodiments, the thermal oil temperature threshold control strategy in step S2 is as follows: when the thermal oil temperature is between the heating demand temperature and the phase change temperature, the collected thermal energy is stored in the phase-changeable heat storage unit; when the thermal oil temperature exceeds the phase change temperature, the phase-changeable heat storage unit switches to the heating circuit. In some embodiments, the parameters optimized for the solar thermal collection unit in step S5 include the area and tilt angle of the solar thermal collection unit, and the parameters optimized for the phase change heat storage unit include the height and volume of the phase change heat storage unit.

[0047] Example 2: A heating device that combines solar heat storage with building renovation, comprising: a heat storage wall, which is arranged at the building unit; a solar heat collection unit, in which heat transfer oil is arranged; a phase change heat storage unit, which is connected to the solar heat collection unit, and is used to collect heat from the solar heat collection unit and heat the building unit; a heating unit, which is connected to the phase change heat storage unit through a multi-circuit temperature control unit, and is used to supplement heat during non-peak hours at night and when the sensible heat reserve is insufficient; a multi-circuit temperature control unit, which is respectively connected to the heating unit and the phase change heat storage unit, and is used to switch the heating mode according to the temperature and the time-of-use electricity price strategy. In some embodiments, the thickness of the heat storage wall is 0.2m, the thermal conductivity is 0.55W / m·K, the heat capacity is 3000kJ / m3·K, and the solar absorption rate is 0.7. In some embodiments, the solar heat collection unit is a vacuum tube collector, and the surface area of ​​the solar heat collection unit is 45m 2 , with an inclination of 30°.

[0048] Example 3: A heating system combining solar thermal storage and building renovation, comprising: the heating device combining solar thermal storage and building renovation disclosed in Example 2 above; a TRNSYS dynamic simulation module for constructing a building heat load model and a heating system comparative analysis model; a time-of-use electricity price response module for controlling the start and stop of the heating unit and the heat supply and release of the phase change heat storage unit according to the electricity price period, maintaining the heat storage temperature at or above 40°C; a PID dynamic adjustment module for releasing phase change latent heat and triggering auxiliary heating of the heating unit based on the indoor temperature and sensible heat reserve; and a GenOpt cost optimization module for optimizing the parameters of the solar thermal collection unit and / or the phase change heat storage unit to obtain a lifecycle cost minimization strategy. In some embodiments, the GenOpt cost optimization module is coupled with the TRNSYS dynamic simulation module and uses the Hooke-Jeeves search method as an optimization method to optimize the parameters of the solar thermal collection unit, the phase change heat storage unit, the supplementary heat strategy, and the heating system comparative analysis model, with the objective function being to minimize operating cost. In some embodiments, the time-of-use electricity price response module is set as follows: during the daytime, when the temperature of the thermal oil is between the heating demand temperature and the phase change temperature, the collected heat energy is stored in the phase-changing heat storage unit; when the temperature of the thermal oil is higher than the phase change temperature, the phase-changing heat storage unit switches to the heating circuit; during the nighttime period, from 23:00 to 7:00, combined with the night-time time-of-use electricity price strategy, the electric boiler is started to supplement heat, and the temperature of the heat storage tank is maintained at not less than 40°C through the dynamic adjustment module. When the indoor temperature is below 20°C, the phase change latent heat is released first, and when the sensible heat reserve is insufficient, the electric boiler is triggered to assist in heating.

[0049] Example 4: A heating system that combines solar thermal storage with building renovation, with a building area of ​​105 square meters. The building is located in southern Shaanxi. Most of the traditional houses there have sloping roofs, with one or two floors of earthenware or brick-concrete structures, and the indoor temperature is low in winter. Power equipment such as air conditioners are not popular, so passive heating is a good choice. Taking into account the characteristics of traditional houses in southern Shaanxi, the building is renovated: the walls are made of thermal insulation materials, with a floor height of 3.5 meters. A skylight is added on one side of the roof to increase the sunlight exposure rate. The window-to-wall ratio of the house is changed to maximize the reception of solar energy. A vacuum tube solar collector is arranged on the south side of the house and connected to the phase change heat storage tank on the ground. The model is established in this way. Table 1 shows the main dimensions and room information of the building.

[0050] The four exterior walls of the building unit face four directions and are rectangular in shape.

[0051] composition living room Room 1 Room 2 Other rooms Total area area <![CDATA[67.5m 2 ]]> 3.6m×3.2m 3.9m×3.2m 3m×4.5m 14m×7.5m

[0052] Table 1: Main dimensions and room information of the building

[0053] Assume the equipment power is approximately 1.5kW, the number of people in the room is 5, and the lighting power is 1kW. The windows are double-glazed with 70% internal shading, located in the east, south, and west directions. Figure 1 , Figure 2 The plan and perspective views of the building are given. The wall structure has a great influence on the heat load, as shown in Tables 2, 3, 4 and

[0054] Table 5 describes the wall structure.

[0055]

[0056] Table 2: Common wall parameters

[0057]

[0058] Table 3: Roof parameters

[0059]

[0060] Table 4: Floor parameters

[0061] Thickness (m) Thermal conductivity (W / m·K) <![CDATA[Heat capacity (kJ / m 3 ·K)]]> Solar absorptivity 0.2 0.55 3000 0.7

[0062] Table 5: Thermal storage wall parameters

[0063] The thermal conductivity (U value) of each window is 1.4W / m 2 ·K, the thermal conductivity of the roof is 0.233W / m2·K, and the heat load of the building is calculated by TRNSYS18. Figure 3The flowchart for programming the transient thermal behavior of the cold storage room is shown. In the TRNSYS simulation environment, the building rooms will be processed and exported to the TRNSYS building component (type 56) and described using TRNBuild definitions. Building materials, orientation, ventilation, permeability, external and internal heat gains, and the building's set humidity and temperature can all be accounted for by combining TRNBuild with multi-zone building modeling of the building component (type 56). The designed building component (type 56) generates the temperature and sensible heat load output required by the simulated heating system to maintain the specified room conditions. In order to achieve high-quality thermal comfort conditions, a temperature setting of 22°C is required. At this temperature level, the building's peak hourly heat load is approximately 4379kJ, while the original building's maximum heat load is 6537kJ, a reduction of approximately 33%. Figure 4 A significant reduction in monthly heating loads was shown.

[0064] In terms of system layout and operation, the system is as follows: Figure 5 As shown in the figure, it consists of a vacuum tube collector, a water tank, a phase change heat storage tank, an electric boiler and a multi-circuit temperature control unit, and realizes dynamic energy scheduling based on the thermal oil temperature threshold control strategy. During the day, the thermal oil temperature is between the heating demand temperature (35°C) and the phase change temperature (50°C). When the phase change temperature is higher than the phase change temperature, it switches to the PCM heat storage circuit for heating. Combined with the night time electricity price strategy (23:00-7:00), the electric boiler is started to supplement heat, and the temperature of the hot water storage tank is maintained at no less than 40°C through PID control. When the indoor temperature is below 20°C, the phase change latent heat is released first, and when the sensible heat reserve is insufficient, the electric boiler is triggered to assist in heating.

[0065] In terms of mathematical models, regarding solar thermal collectors: Thermal modeling of solar thermal collectors is based on the generated useful energy flow and the efficiency of the collector. The energy efficiency of the solar thermal collector can be derived from formula (1):

[0066]

[0067] Where: η – solar energy collection efficiency; Q u – Heat output of the collector, W; A – Solar collector area, m 2 ;I T – Hemispherical solar irradiance on the collector plane, W / m 2 ; F R – Thermal efficiency coefficient of the collector; U L – Heat loss coefficient per unit area of ​​the collector; α – Absorption rate; T0 – Collector inlet temperature; T a – Ambient temperature; Calculate the radiation intensity on the collector surface:

[0068]

[0069] Where: IT – Solar radiation intensity; I Dθ – Direct radiation intensity; I dθ – scattered radiation intensity; I Rθ – Ground reflected radiation intensity; I DH – solar radiation intensity on the horizontal plane; θ T – angle of incidence; I dH – scattering intensity on the horizontal plane; – Ground reflectance; due to heat loss coefficient U L Changes with temperature. Considering the linear relationship between the loss coefficient and the temperature difference, formula (1) can be written as follows:

[0070]

[0071] The general solar collector thermal efficiency equation can be calculated according to formula (4);

[0072]

[0073] Where: a0 – the maximum efficiency of the solar thermal collector, dimensionless; a1 – (T0 – T a )=0, W / (m 2 ·K); a2 – temperature-related heat transfer coefficient, W / (m 2 ·K 2 );

[0074] Regarding the water tank: Assume that the type 158 water tank used in this application consists of N (N = 4) fully mixed equal-volume segments, which can be modeled. A heat exchanger is installed within the tank. The energy balance for each segment i is given by Equation 5:

[0075]

[0076] Where: M i is the mass flow rate of the fluid in section i (kg·h -1 ), T i is the temperature of the water tank in section i (℃), Q useful Energ y is the useful energy generated by the solar collector and flowing into the water tank, Q load Q is the energy of hot water leaving the tank and flowing to the floor radiant pipe. losses Energy lost to the environment.

[0077] Q useful_Energy =α i m h C P (T t -T i )(6)

[0078] Q load =β i m l C P (T i -T b ) (7)

[0079] Q losses =U i A i (T i -T a )(8)

[0080] Among them, m h is the mass flow rate of the fluid leaving the solar collector (kg·h -1 ), m l is the mass flow rate of fluid leaving the tank and flowing to the building, T t and T b are the temperatures at the top and bottom of the tank respectively. i is the heat loss coefficient between the ith water tank node and the environment (kJ·h -1 ·m -2 ·K -1 ), A i is the surface of the i-th tank segment (m2).

[0081]

[0082] α i , β i and γ i There are three control functions. If the i-th segment corresponds to the top of the water tank, then α i =1, otherwise 0. If the i-th segment corresponds to the tank bottom, then β i =1, otherwise 0. If γ i +0, then C i =γ i C P (T i-1 -T i ), otherwise γ i C P (T i -T i+1 ).

[0083] Regarding buildings: Energy gains and losses determine the energy balance of a building. It is possible to utilize energy from a variety of sources, including internal energy generated by humans, electrical appliances, and the use of solar energy. Energy losses are caused by transmission and ventilation. The net heat gain per air node is calculated by Hamdaoui et al.:

[0084] Q l =Q surf +Qair +Q gain +Q solar +Q cond (10)

[0085] Where: Q surf – Convective heat from all interior surfaces (kJ / h); Q air – Heat gained through external wall penetration and ventilation (kJ / h); Q solar – internal gain (through people, equipment, lighting, etc., equal to a constant value when the building is occupied and zero otherwise) (kJ / h); Q solar – Solar radiation heat absorbed by the window (kJ / h); Q cond – heat transferred through the building envelope (kJ / h);

[0086] About solar energy guarantee rate:

[0087]

[0088] Q totalload is the heat load required by the building, Q aux The energy consumption of electric heaters, water pumps and other heating facilities.

[0089] About Phase Change Thermal Storage Tanks: Heat is transferred or delivered to a tank via two different fluids, one of which mixes with the liquid in the tank and the other transfers the heat to the tank via an immersion heat exchanger.

[0090]

[0091] Among them, Q in,tank – Heat of the fluid at the inlet (kJ); Q out,tank – Heat of the fluid at the outlet (kJ); T Tank – Ambient temperature (℃); C Tank –Specific heat capacity of the liquid in the tank (kJ / (kg·°C));

[0092] In the two-phase region, the energy balance solution is different because the temperature of the fluid does not change, the amount of solid matter increases or decreases, and the total energy also changes accordingly. The net change in energy of the two-phase fluid is given by (13);

[0093]

[0094] Q loss,bottom =(A bottom ·U bottom )·(T tank -T env,bottom )

[0095] Q loss,edges=(A edges ·U edges )·(T tank -T env,edges )(14)

[0096] Where: A top– Heat loss surface area of ​​tank top (volume divided by height); A bottom – heat loss surface area of ​​the tank bottom (volume divided by height); A edge – heat loss surface area of ​​the tank edge (perimeter multiplied by height); U top – Heat loss coefficient of the tank top; U bottom – Heat loss coefficient of tank bottom; U edge – Heat loss coefficient of tank edge; T tank – Storage tank temperature (℃); T env,top – Tank ambient temperature lost through the tank top (°C); T env,bottom – Ambient temperature of the tank when the tank bottom is lost (°C); T env,top – Tank ambient temperature, used to measure the loss through the tank edge (°C);

[0097] The liquid flow is completely mixed with the fluid in the tank, leaving the remaining fluid at the tank temperature but in a completely liquid state. The inlet fluid is assumed to have the same properties as the tank fluid. By definition, the outlet mass flow rate is equal to the inlet mass flow rate.

[0098]

[0099] Where: m in –Inlet mass flow rate into the tank (kg / kJ); C p –Specific heat of the tank fluid (kJ / (kg·℃)); T in – Inlet fluid temperature into the gas tank (°C); T tank – Storage tank temperature (°C);

[0100] To alleviate the difficulty of heat exchange between the fluid flowing in the immersion heat exchanger and the melting / freezing fluid, the model assumes that the heat transfer of the heat exchanger is set to: do not consider the mass of the fluid in the heat exchanger, and always assume that the fluid in the heat exchanger has the minimum dielectric constant. The heat transfer rate transferred to the heat storage tank can be expressed as Equation (16):

[0101]

[0102] When no fluid passes through the heat exchanger, the outlet temperature can be expressed as formula (17);

[0103]

[0104] Where: –Inlet mass flow rate into the tank (kg / kJ); C p,hx –Specific heat of the heat exchanger fluid (kJ / (kg·℃)); T in,hx – Temperature of the fluid entering the immersion heat exchanger (°C); T out,hx – Temperature of the fluid leaving the immersion heat exchanger (°C); T tank – Tank temperature (℃);

[0105] About water pumps:

[0106]

[0107] Among them H w is the pump head, P is the pump power, G is the pump flow rate, which is the frequency ratio of the pump; ρ is the fluid density, g is the acceleration of gravity, η is the total efficiency of the pump, F is the actual operating frequency, and F0 is the rated frequency.

[0108] About TRNSYS simulation: This application constructs a comparative analysis model of three typical heating systems. Phase change thermal storage system combined with building thermal storage structure (system 1), traditional building phase change thermal storage system (system 2) and traditional non-thermal storage system (system 3). The focus is on evaluating the differences in key indicators such as thermodynamic performance, solar guarantee factor (SF) and auxiliary energy consumption of different technology combinations. System 1 adopts a collaborative control strategy of active thermal storage and passive envelope structure. System 2 and system 3 are characterized by conventional electric direct heating mode. Through dynamic simulation under all working conditions, the quantitative improvement mechanism of phase change thermal storage technology on system energy efficiency and its coupling effect with building thermal inertia are revealed. Model such as Figure 6 As shown: The main energy source of the system is the solar thermal collector (SC). The amount of heat collected by the solar thermal collector depends mainly on solar radiation. During the heating season, the average monthly solar radiation is 240,000 kJ / (m 2 d). Due to the low outdoor temperatures in the region during winter, the use of water as a heat transfer fluid in the collector has inherent limitations. Therefore, thermal oil is used instead of water to enable the system to operate reliably below 0°C. Specific parameters are detailed in Table 6.

[0109] Collector surface area Fluid specific heat Interception efficiency slope Test flow parameter <![CDATA[45m 2 ]]> 1.67kJ / kg·K 0.8 30 degrees <![CDATA[15kg / h·m 2 ]]>

[0110] Table 6: Flat plate collector parameters

[0111] The system consists of two water tanks: Tank 1 is used to heat the room during the day using solar energy. Tank 1 contains thermal oil, which transfers heat energy to the heating circuit through an oil-water heat exchanger. Tank 2 is used to integrate supplementary heat from the hot water storage tank and electric boiler into the system. The specific data of Tank 1 are: Tank volume 1m 3 , water tank height 1.6m, top loss coefficient 0.08W / m 2K, edge loss coefficient 0.08W / m 2 K, bottom loss coefficient 0.08W / m 2 ·K, fluid specific heat 1.67kJ / kg·K, fluid density 995kg / m 3 , fluid thermal conductivity 0.1204W / m·K, fluid viscosity 1.7908kg / m·h; the specific parameters of water tank 2 are: water tank volume 1.2m 3 , water tank height 1m, top loss coefficient 0.08W / m 2 K, edge loss coefficient 0.08W / m 2 K, bottom loss coefficient 0.08W / m 2 ·K, fluid specific heat 4.19kJ / kg·K, fluid density 1000kg / m 3 , fluid thermal conductivity 0.618W / m·K, fluid viscosity 2.3508kg / m·h. The thermal storage tank stores excess solar heat collected during the day and provides heating for the room when energy is scarce. The electric boiler is connected to the thermal storage tank through two circuits, enabling it to heat the thermal storage tank at night when electricity prices are off-peak, thereby compensating for the problem of insufficient solar energy supply. The specific parameters of the phase change thermal storage tank are: thermal storage tank volume 0.494m 3 , heat storage tank height 1m, top loss coefficient 0.083W / m 2 K, edge loss coefficient 0.083W / m 2 K, bottom loss coefficient 0.083W / m 2 ·K, liquid specific heat 2.384kJ / kg·K, liquid density 760kg / m 3 , latent heat of fusion 213kJ / kg, phase transition temperature 50℃, solid specific heat 1.850kJ / kg·K, solid density 880kg / m 3 The specific parameters of the electric boiler are: rated flow rate 8000 kJ / h, fluid specific heat 4.19 kJ / kg·K, set temperature 53°C, and boiler efficiency 0.85. The room must meet occupancy requirements. Please refer to Table 7 for specific room parameter settings.

[0112]

[0113] Table 7: Room specific settings

[0114] The system is controlled by the start and stop operation of the switch. The control function generated by the switch type differential controller (2B type) has two possible output states: 1 (on) and 0 (off). The control signal value is obtained by comparing the two dead zone temperature differences (D Th and D T1 ) and the upper and lower threshold temperature difference (T h and T l) is determined. The control function value input at the previous time step determines the updated value of the control function. When the temperature difference exceeds 10℃ (T h -T l ≥10℃), the water pump starts. When the temperature difference is lower than 2℃(T h -T l ≤2°C), the pump is deactivated. This controller is equipped with an upper limit cutoff. If the upper limit condition is exceeded, the control function is set to 0 (off) regardless of the deadband condition. The maximum tank cutoff temperature is 90°C.

[0115] Simulation process: Detailed workflow such as Figure 7 Meteorological data files were generated using Meteonorm software, and a system model was constructed based on the system schematic. The model's main components include solar thermal collectors, a heat storage tank, a circulation pump, a temperature controller, a phase-change thermal storage tank, a boiler, and a heat exchanger. The analysis was based on the winter heating period, from November 15th to March 15th of the following year. Actual operating data was used to assign reasonable initial input values ​​to the system components. Calculations included: heating duration (operating time requirement), heating efficiency, equilibrium temperature (steady-state thermal balance), thermal storage tank performance (e.g., capacity, charge and discharge rate), and heating efficiency verification (e.g., solar thermal conversion rate). Simulation results were output in the form of real-time graphical output (e.g., temperature curves, energy flow trends). Regarding the system's heating operating conditions in the basic heating analysis, for the retrofitted building, during the heating season, the solar thermal collectors collected 1685.92 kWh of thermal energy, while the total room heat load was 1639.64 kWh. Due to energy losses during the storage process, additional energy input was required. The electric boiler charges the thermal storage tank during off-peak electricity price periods at night to make up for the losses and ensure that the room's heat demand is met. Figure 8 Displays the outdoor temperature, indoor heating temperature, and supply / return water temperatures during the heating season. The indoor temperature fluctuates between 17.12°C and 27.02°C, generally meeting winter heating requirements. The lowest indoor temperature coincides with the peak heat load during extreme cold outdoor conditions. The heating water supply temperature remains stable at 35°C, unaffected by external environmental fluctuations, demonstrating robust system control capabilities. The return water temperature remains between 20.21°C and 27.2°C, generally meeting the indoor supply and return water temperature differential requirements for winter heating.

[0116] Figure 9The figure shows the temperature changes and heat storage of a phase-change thermal storage tank during the heating season. The red line represents the average temperature within the tank. Green represents electric boiler heating, yellow represents solar charging, and purple represents tank discharge. The average temperature within the tank is determined by the energy input from the solar energy and electric boiler, as well as the heat discharged from the tank. When heating is insufficient, the tank releases stored heat. During periods of peak sunlight, solar energy replenishes the stored heat. The temperature reached a peak of 84.32°C in February. This was due to strong solar radiation in the first two days, which met indoor heating needs and caused the tank temperature to rise rapidly. In the following two days, solar radiation weakened, increasing the temperature difference between the tank and the surrounding environment and heat loss. This led to a significant heat loss in the tank, causing the temperature to drop sharply. The amount of heat supplied by the electric boiler is affected by the temperature of the thermal storage tank from the previous day. When the average tank temperature is high, the energy stored in the tank is sufficient to meet indoor heating needs, eliminating the need for the boiler to operate at full capacity. In most cases, the tank temperature remains at 50°C, which coincides with the phase-change temperature of the material. Achieving this phase-change temperature improves thermal storage efficiency because the material absorbs or releases latent heat during the phase-change process.

[0117] Analysis of system operation characteristics within 72 hours of the coldest month: Figure 10 The system's dynamic response characteristics under typical low-temperature operating conditions for 72 hours are shown. During this period, external temperature influences caused the temperature difference between the collector inlet and outlet to increase. When the collector temperature exceeded 50°C, heat was stored in the thermal storage tank, while when it exceeded 35°C, the heat was directed to indoor heating. On the first day, the solar collector operated at low temperatures, resulting in minimal heat transfer to the thermal storage tank. To compensate, the electric boiler operated at full capacity to supplement the thermal energy in the thermal storage tank. From 7:00 AM to 12:00 AM, the majority of the heating load was provided by heat stored in the thermal storage tank. During this period, the solid-to-liquid ratio of the phase change material in the thermal storage tank increased from 0.03 to 0.44, indicating that most of the liquid phase transformed into a solid phase, releasing latent heat to meet the heating demand. After 11:00 PM, the electric boiler heated the thermal storage tank, causing the solid-to-liquid ratio of the phase change material to decrease from 0.44 to 0.12. On the second day, solar radiation levels were high. Starting at 32:00 AM, the solar collector primarily provided daytime heating, storing excess heat in the thermal storage tank. The solid-to-liquid ratio in the thermal storage tank further decreases, reaching complete liquefaction. The average tank temperature rises to 80°C, reaching its peak at 40 hours. At 4:00 PM, sunset reduces the solar heat source, lowering the tank temperature and releasing energy. The sensible heat in the tank is dissipated. After 56 hours, the sensible heat is completely depleted. Because the solar temperature remains insufficient, the tank continues to release latent heat, causing the solid-to-liquid ratio to increase. This cycle repeats. Figure 11The temperature change of the hot water tank is shown. The hot water tank is connected to the indoor heating circuit through a heat exchanger. The yellow and red lines in the figure represent the temperature change of the hot end. The blue and cyan lines represent the temperature change of the cold end. The supply side fluid changes from red to yellow when transferring heat through the heat exchanger. The red curve represents the inlet temperature and the yellow curve represents the outlet temperature after energy transfer. On the user side, the fluid temperature changes from blue to cyan, and the cyan curve stabilizes at 35°C, which meets the requirements of winter heating. The brown line represents the heating flow rate, which is consistent with the Figure 10 The cyan curve in the figure is consistent with the cyan curve in the figure, which activates when solar utilization is low to compensate for reduced energy input. As the outlet temperature of the heating tank gradually increases, the temperature difference between the red and yellow curves reflects the amount of heat delivered to the user. When there is fluid flow, the heating supply increases, while when the flow rate drops to zero, the heating supply decreases. The cold-side temperature of the heat exchanger is affected by the level of solar radiation, with a significant increase at the 12th, 36th, 40th, and 60th hours. When the solar radiation temperature exceeds 40°C, the fluid entering the room is preheated, increasing its temperature and reducing the heat load on the water storage tank. Figure 12 A phase change thermal storage tank was analyzed. The line graph shows flow rate changes, and the shaded area represents energy changes. During the nighttime off-peak electricity price period, the electric boiler was activated, simultaneously heating the PCM storage tank and the liquid. After 47 hours, the heating input to the tank decreased significantly, reaching zero after 50 hours. This is because the excessive solar charge from the previous day ensured that the stored energy in the tank was sufficient to meet heating demand, eliminating the need for additional boiler input. Solar energy above 50°C was used to heat the thermal storage tank, reaching a peak at 3:00 PM. Due to energy losses, the stored heat must be slightly greater than the thermal storage discharge to meet demand. Peak electricity prices are from 7:00 AM to 11:00 PM, while off-peak electricity prices are from 11:00 PM to 1:00 AM. The thermal storage tank releases energy during high-price periods to meet demand, as shown in the cyan portion of the graph. At 12:00 PM, the solar temperature exceeds the heating demand, so no energy is required from the thermal storage tank. At 4:00 PM, the solar temperature reaches its lowest point, and the thermal storage tank provides most of the room's energy needs, reaching its maximum energy release. Part of the solar energy exceeding 50°C is used to heat the heat storage tank, reaching the charging peak at 37 hours. Due to energy loss, the stored heat is slightly higher than the discharged heat to ensure that it meets the system requirements. During the peak electricity price period (7:00-23:00), the heat storage tank releases the stored energy (indicated by the cyan part in the figure) to supplement the heating demand. Within 12 hours, when the solar-driven heating temperature exceeds the heating requirement, the water tank will not release energy. By 42 hours, when the solar-driven heating temperature drops to the lowest, the water tank will provide most of the room's heating needs, achieving peak discharge to compensate for the lack of solar energy.

[0118] About heating temperature under different weather conditions: This simulation analyzes the changes in heating temperature and indoor temperature under different weather conditions in January, such as Figure 13 As shown. In the coldest case, the indoor temperature fluctuates between 15℃ and 18℃, while the heating temperature is affected, temporarily dropping at 5 hours and then returning to 35℃ at 10 hours. Due to the low outdoor temperature, the heat load reaches its peak, and the indoor temperature is not high, but also tends to be stable. The heating temperature is most affected by the outdoor changes on cloudy days. During normal periods, the heating temperature is hardly affected, and the room temperature is maintained at 20℃±2℃, which meets the heating needs. About the system energy consumption and operating costs: Figure 14 and 15 The total power consumption of the water pumps and the system operating costs are shown separately. The electric boiler operates during the off-peak electricity price period (23:00-01:00), as shown in Table 8. The other water pumps are controlled by different control signals, resulting in different operating times. The heating water pump and the auxiliary heating water pump have longer operating times. These components account for the highest proportion of total consumption in the data. Figure 15 As shown in Figure 2, the system operating cost includes the energy consumption of the pump and the electricity consumption of the electric boiler for heating. During the entire heating season (November 15th to March 15th of the following year), the daily energy consumption of the water pump remains almost the same, which is consistent with the Figure 14 The conclusion is consistent with the previous one. Electric boiler electricity consumption accounts for the majority of operating costs, and its usage is adjusted based on the daily changes in the amount of heat stored in the water tank. Over the entire heating season, the cumulative operating costs totaled 624.20 yuan.

[0119] Power consumption (kWh) Peak (7:00-23:00) (yuan / kWh) Valley value (23:00-7:00) (yuan / kWh) 0-1260 0.5483 0.2983 1261-2450 0.5983 0.3483 2451 or more 0.8343 0.5983

[0120] Table 8: Electricity Prices

[0121] In terms of the comparison of different systems, regarding the impact of thermal storage walls: thermal storage structures can have a significant impact on the heat load of a building, among which the thickness change of the thermal storage wall is the most significant, such as Figure 16 When the thickness increases, the total heat capacity of the thermal storage material increases, and more solar energy can be stored. In areas with large temperature differences between day and night, the heat absorbed during the day is released at night, reducing the demand for heating and thus reducing the heat load. If the heat release time is delayed for too long (such as more than 24 hours), the heat may not be used in time, and additional heating may be required. The thicker the material, the lower the thermal resistance. As the temperature rises, heat transfer slows. In cloudy or continuously cold conditions, thermal storage walls absorb insufficient heat. Excessively thick walls can hinder indoor heat retention due to excessive thermal resistance, increasing the heat load. The relationship between thermal storage wall thickness and heat load is nonlinear, and an optimal solution exists. In suitable climates, moderately increasing the thickness can reduce the heat load; however, exceeding a critical value can increase the heat load due to thermal resistance and delay effects. After comprehensive consideration, a thickness of 0.2m was selected.

[0122] Regarding the operating costs of System 2: System 2 is a system that combines a building that has not undergone thermal storage renovation with heat storage. Under the same conditions, the system without thermal storage renovation cannot meet the heating requirements. After meeting the heating requirements, the required cost consumption is as follows: Figure 17 Compared with the original system, the energy consumption of the system without thermal storage wall is significantly increased. Due to the increase in the heat load of the system, the solar heat supply is insufficient compared with the heat load required by the room, and the increase in the proportion of electric heating increases the energy consumption of the system. Figure 18 The system's heat storage is significantly higher than that of the system with thermal storage wall, and the heat release is also significantly improved. Regarding the operating cost of System 3: System 3 is a traditional heating system. The system absorbs heat through solar collectors, transfers it to the hot water tank, and then heats the user side. When the temperature is insufficient, auxiliary heating is performed. The system is modeled in TRNSYS as follows Figure 19 Under the same conditions, system 3 cannot meet the heating requirements. After meeting the heating requirements, the required cost consumption is as follows Figure 20 .and Figure 15 , Figure 17 In comparison, the system's auxiliary heating energy consumption has increased significantly, with the maximum daily cost rising from 7.4 yuan, 18.5 yuan to 31.2 yuan. The system's heat storage facilities are imperfect, the water tank's heat storage capacity is smaller than that of the phase change heat storage tank, and the solar energy fluctuates greatly. When the external environment is low, the required auxiliary heating amount increases.

[0123] Regarding system energy consumption evaluation: This application uses the solar energy guarantee rate (SF) as the evaluation index of system energy consumption, that is, the ratio of solar energy to system heat load, which is also the percentage of solar energy in the total system energy. Figure 21 ,25 In system 1, the average value of SF is 54.5%, in system 2 the average value is 40.6%, and in system 3, SF is only 29.3%, which is 25.2% lower than that of system 1. In system 1, the total operating time of the electric boiler is the shortest, with a total operating time of 227h, accounting for 7.9% of the total heating season, and providing 1407.21kWh of heat for the system. In system 2, the operating time of the electric boiler increases by 537h, with a total operating time of 764 hours, providing 2409.99kWh of heat for the system, an increase of 70.3% compared with system 1, accounting for 26.5% of the total heating season. The electric boiler in system 3 provides 3691.61kWh of heat, which is 34.7% higher than that of system 2. Figure 17 ,20 costs can be concluded that the heat storage system plays an important role in solar heating. The main reason for the large cost difference is the increase in electricity consumption. The secondary reason is that without the heat storage system, the operation time of the electric boiler has changed from night operation to operation when solar energy is insufficient, and it also works during the day when electricity prices are high. Figure 22 It can be seen that the solar energy supply for System 1 mostly exceeds 75%. Only on a few cloudy days, when solar radiation is low, the fluid temperature after heating is not high, and there is no gain in the heating system. The main heating is provided by electric heating and stored solar energy from the previous day.

[0124] About model optimization: Genopt is a Java-based optimization program that minimizes cost objective functions and can be used in conjunction with text-based simulation programs. This application uses the TrnOpt interface component of TRNSYS to connect to the external optimization program Genopt. The Hooke-Jeeves search method is selected as the optimization method. This method can use probe search and pattern conversion to quickly solve unconstrained optimization problems with few variables. The optimization process is as follows Figure 23 The purpose of the detection search is to find a point that is better than the surrounding reference points, so as to determine the direction of progress that is conducive to the result. The objective function is continuously optimized along this direction and gradually moves towards the optimal result. The main direction of optimization is to change the tilt angle and area of ​​the solar collector, and comprehensively consider the system cost to achieve the goal. In order to save operating costs, different heat supplement strategies and different forms of the system are compared and analyzed, such as Figure 24 , 25. Changing the collector tilt angle has little impact on the system, while changing the collector area has a significant impact. First, assuming other conditions remain unchanged, such as solar radiation intensity, ambient temperature, and collector efficiency, the amount of heat collected should be proportional to the area. In this case, the relationship should be linear, but when the collector area increases to a certain extent, heat loss will increase. A larger area means more surface area in contact with the surrounding environment, which may lead to greater heat loss. In this case, as the area increases, the growth of the amount of heat collected may no longer remain linear, but may gradually slow down, because the increased heat loss will offset some of the collected heat. In this case, it may exhibit sublinear growth, that is, a slower growth rate. However, it is also necessary to consider whether other parts of the system can accommodate the larger area. If the collector area increases without a corresponding increase in the heat transfer fluid flow rate or the storage system capacity, a bottleneck may be reached, limiting the increase in the amount of heat collected. This may result in the amount of heat collected stagnating after a certain area increase, or even reaching a plateau. Figure 24 , 26 shows that the heat collection area is 20m 2 It can maintain basic linear growth at 25m 2 Then increase the lifting capacity and gradually reduce it, but if the system supply and return water temperature is to be kept in the normal range, the collector area needs to be within 30m 2 As the collector area increases, the operating cost of the system will continue to decrease. Figure 25 , 27. Increasing the collector area increases the initial cost, while reducing the collector area increases the operating cost. After comprehensive comparison, 37m 2 collector area.

[0125] The heat replenishment control strategy, which is affected by the unit's operating status, will result in a short heat replenishment time, which will cause the water tank temperature to be too high. Therefore, the system's heat replenishment control is changed to start the heat replenishment normally when the unit is running and the heat storage tank reaches the set temperature. In addition, in order to solve the problem of low system energy efficiency due to high EC of the pump, the operation regulation of the pump was improved. After comprehensive improvements, Figure 28 , the system's operating costs were reduced from 624.20 yuan to 498.16 yuan, a decrease of 20.2%. SF increased during daily operation, with the average value increasing from 54.5% to 61.8%. Regarding carbon emission calculation: The system's carbon emission reduction can be calculated according to formula (21):

[0126] ΔC=C t -(C y +C f ) (twenty one)

[0127] Where: ΔC – net emission reduction (kgCO2 / year); C t – Solar energy replaces traditional energy to reduce emissions (kgCO2 / year); C y – Average annual carbon emissions of solar energy systems (kgCO2 / year); C f – Carbon emissions from auxiliary energy (kgCO2 / year);

[0128] C t =Q total η solar EF substitute (twenty two)

[0129] Where: Q total – Total annual heating demand (kWh); η solar –Solar energy guarantee rate (%); EF substitute – Carbon emission coefficient of alternative energy (kgCO2 / kWh);

[0130]

[0131] Among them: A i – Area or quantity of the i-th material / component (e.g. collector area (m 2 ), number of water storage tanks); EF cl,i –Specific embodied carbon emissions of material / component type i (kg CO2 / m 2 or kg CO2 / unit); N – system service life (years);

[0132] C f =Q total ·(1-η solar )·EF aux (twenty four)

[0133] Among them, EF aux – Carbon emission coefficient of auxiliary energy (kgCO2 / kWh); calculated, 1189.07 kgCO2 can be reduced annually. These results highlight the system’s enormous energy-saving potential and broad long-term application prospects.

[0134] Regarding economic analysis: The net present value of the financial valuation is derived from formula (25). It is the sum of the capital cost C0 and the annual operating cost. To calculate the operating cost, the annual electricity savings P el Multiply it by the electricity cost C1, and then multiply it by the coefficient [1 / (1+γ)]. The last coefficient represents the impact of the discount coefficient γ in the operating cost.

[0135]

[0136] The main costs of the system are the renovation of the thermal storage wall and the cost of the thermal storage tank and the evacuated tube collector. The solar evacuated tube collector area is 37m 2 The cost is about 16780 yuan. The cost of thermal storage wall is 160 yuan / m 2 After renovation, the building area is 56m 2 , the total cost is calculated to be 8960 yuan. The capacity of the heat storage tank is 0.494m3, which is sufficient to meet the maximum daily heat storage demand. The mass of paraffin is 375.5kg, and the total cost of the water tank is about 10,500 yuan. The system includes 6 water pumps, which cost 6,000 yuan, and the total initial investment is 42,240 yuan. The rural clean energy heating transformation policy subsidy is about 20,000 yuan, and the net investment cost is reduced to 22,240 yuan. Figure 29 As shown in Figure 2, the system achieves a return on investment (ROI) through reduced operating energy consumption, with an estimated payback period of 13 years. This payback period could be further shortened if more favorable regional policies are implemented.

[0137] In general, in order to explore the application of the heating system combining solar thermal storage with local building renovation, a multi-loop dynamic coupling simulation model was constructed based on the TRNSYS platform. A time-sharing and partitioning control strategy was adopted (solar energy is used for priority heat storage during the day, electric boilers are used for supplementary heat storage at night, and heat is released on demand on the demand side), which effectively solved the efficiency loss problem of the traditional heat storage system. Taking typical rural houses in Xi'an as the research object, through dynamic simulation of the whole heating season, the research results show that compared with the traditional system, the system proposed in this application shows a more stable energy supply, a higher proportion of solar energy and less operating costs, and has broad application prospects in the heat storage system of small houses. The main conclusions are as follows: (1) The heat load of the low-carbon building with thermal storage wall during the heating period is 1639.64kWh, which is 48.1% lower than the heat load of 3159.02kWh during the heating period of the traditional building. (2) The solar energy fraction of the system with thermal storage wall was the highest, accounting for 54.5% of the system energy, while that of the system with thermal storage was 40.6%. In the system without thermal storage, the SF was only 29.3%, which was 25.2% lower than that of the phase change thermal storage tank system. (3) In the low-carbon building system with thermal storage, the total operating time of the electric boiler was the shortest, with a total operating time of 227 hours, accounting for 7.9% of the total heating season, and providing 1407.21kWh of heat to the system. In the normal building system, the operating time of the electric boiler increased by 537 hours, with a total operating time of 764 hours, providing 2409.99kWh of heat to the system, an increase of 70.3% compared to the modified system, accounting for 26.5% of the total heating season. In the system without phase change thermal storage and without modification, the electric boiler provided 3691.61kWh of heat, which was 34.7% higher than that of the system with thermal storage. (4) In the heating system, the area of ​​the solar collector and the system control strategy have a great influence on the power consumption of the system. When the solar collector area is changed to 37 m2 and the heating temperature control is changed to the temperature control of the phase change tank, the solar fraction of the system is increased from 54.5% to 61.8%, the initial investment is reduced, and the system can heat the building normally while using less auxiliary heat sources to provide additional heat, and the stability is greatly improved.

[0138] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0139] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0140] The above is a detailed introduction to the heating method, device, system, product, equipment and medium that combines solar heat storage and building renovation provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A heating method combining solar thermal storage and building renovation, characterized in that: The following steps are involved: S1, installing thermal storage walls in the building's exterior wall structure to enhance the building's thermal inertia and reduce heating load; S2, collects heat during the day through the solar thermal collection unit, stores it preferentially in the phase change thermal storage unit, and controls energy distribution based on the thermal oil temperature threshold; S3, based on the night-time time-of-use electricity price strategy, uses the heating unit to supplement heat to the phase change thermal storage unit during off-peak hours to maintain the thermal storage temperature at no less than 40°C; S4 dynamically adjusts the heating circuit through a multi-circuit temperature control unit. When the indoor temperature of the building is below 20°C, the latent heat of phase change is released first. When the sensible heat reserve is insufficient, the heating unit is triggered to provide auxiliary heating. S5, through the coupling of GenOpt algorithm and TRNSYS dynamic simulation algorithm, optimizes the parameters of solar thermal collection unit and / or phase change thermal storage unit through Hooke-Jeeves search method, and outputs the full life cycle cost minimization strategy.

2. The heating method combining solar thermal storage and building renovation as claimed in claim 1, characterized in that: The thermal oil temperature threshold control strategy in step S2 is: when the thermal oil temperature is between the heating demand temperature and the phase change temperature, the collected thermal energy is stored in the phase-changing heat storage unit; when the thermal oil temperature is higher than the phase change temperature, the phase-changing heat storage unit switches to the heating circuit.

3. The heating method combining solar thermal storage and building renovation as claimed in claim 1, characterized in that: The parameters of the solar thermal collection unit optimized in step S5 include the area and tilt angle of the solar thermal collection unit, and the parameters of the phase change heat storage unit optimized include the height and volume of the phase change heat storage unit.

4. A heating device combining solar thermal storage and building renovation, characterized in that: include: Thermal storage walls are installed at building units; A solar heat collection unit, wherein heat transfer oil is provided in the solar heat collection unit; a phase change heat storage unit connected to the solar thermal collection unit, for collecting heat from the solar thermal collection unit and heating the building unit; The heating unit is connected to the phase change heat storage unit through the control of the multi-circuit temperature control unit, and is used to supplement heat during non-peak hours at night and when the sensible heat reserve is insufficient; The multi-circuit temperature control unit is connected to the heating unit and the phase change heat storage unit respectively, and is used to switch the heating mode according to the temperature and time-of-use electricity price strategy.

5. The heating device combining solar thermal storage and building renovation as claimed in claim 4, characterized in that: The thickness of the heat storage wall is 0.2m, the thermal conductivity is 0.55W / m·K, the heat capacity is 3000kJ / m3·K, and the solar absorptivity is 0.

7.

6. The heating device combining solar thermal storage and building renovation as claimed in claim 4, characterized in that: The solar heat collection unit is a vacuum tube collector with a surface area of ​​45m 2 , with an inclination of 30°.

7. A heating system combining solar thermal storage and building renovation, characterized in that: include: A heating device combining solar thermal storage and building renovation as described in any one of claims 4 to 6; TRNSYS dynamic simulation module is used to build building heat load models and heating system comparative analysis models; The time-of-use electricity price response module is used to control the start and stop of the heating unit and the heat supply and release of the phase change heat storage unit according to the electricity price period, maintaining the heat storage temperature at not less than 40°C; PID dynamic adjustment module, used to release phase change latent heat and trigger heating unit to provide auxiliary heating according to indoor temperature and sensible heat reserve; The GenOpt cost optimization module is used to optimize the parameters of the solar thermal collection unit and / or the phase change thermal storage unit to obtain a full life cycle cost minimization strategy.

8. The heating system combining solar thermal storage and building renovation as claimed in claim 7, characterized in that: The GenOpt cost optimization module is coupled with the TRNSYS dynamic simulation module, and the Hooke-Jeeves search method is used as the optimization method to optimize the parameters of the solar thermal collection unit, the parameters of the phase change heat storage unit, the heat supplement strategy, and the heating system comparative analysis model. The objective function is to minimize the operating cost.

9. The heating system combining solar thermal storage and building renovation as claimed in claim 7, characterized in that: The time-of-use electricity price response module is set as follows: during the daytime, when the temperature of the thermal oil is between the heating demand temperature and the phase change temperature, the collected thermal energy is stored in the phase-changing heat storage unit; when the temperature of the thermal oil is higher than the phase change temperature, the phase-changing heat storage unit switches to the heating circuit; during the nighttime period, from 23:00 to 7:00, combined with the nighttime time-of-use electricity price strategy, the electric boiler is started to supplement heat, and the temperature of the hot water storage tank is maintained at no less than 40°C through the dynamic adjustment module. When the indoor temperature is below 20°C, the phase change latent heat is released first, and when the sensible heat reserve is insufficient, the electric boiler is triggered to assist in heating.

10. An electronic device, characterized in that: It comprises a memory and a processor, wherein: the memory is used to store a computer program; the processor is used to execute the computer program to implement the heating method combining solar thermal storage and building renovation as described in any one of claims 1 to 3.

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