Heating system based on combination of phase change energy storage and air source heat pump

Abstract

The invention discloses a heating system based on phase change energy storage combined with an air source heat pump, and aims to solve the problems that a traditional heating system is high in investment cost and harsh in geological requirement and works discontinuously and unstably due to the influence of power supply fluctuation. The air cooling heating unit and the phase change heat storage water tank are combined, so that the electricity utilization flexibility of the heating system is improved, and the problem of power supply fluctuation is solved. Through flexible control of the multiple pipelines, the electromagnetic valve, the water pump and other assemblies, heat can be distributed according to needs. And meanwhile, multiple modes are set according to user power supply, and it is ensured that the heating system can operate efficiently under different working conditions while the user requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of heating and cooling, and in particular to a heating system based on phase change energy storage combined with an air source heat pump. Background Art

[0002] With the deepening implementation of the strategic goals of "carbon peak" and "carbon neutrality," the low-carbon transformation of building energy systems has become a key breakthrough in achieving an energy revolution. Current building air conditioning systems face three technical contradictions: first, the fundamental conflict between the intermittent nature of renewable energy generation and the stability requirements of traditional power grids; second, the structural mismatch between rigid energy supply equipment and the need for dynamic load response; and third, the systemic contradiction between the absorption bottleneck caused by a high proportion of renewable energy access and the insufficient equipment control capabilities. According to statistics, the renewable energy curtailment rate in my country's building sector, resulting from the temporal and spatial mismatch between supply and demand, has reached 23.4%. This contradiction is particularly prominent in complex climate zones with hot summers, cold winters, and large diurnal temperature differences. There is an urgent need to develop and build intelligent energy supply systems with dynamic response capabilities.

[0003] The prior art (patent document number CN204665459U) proposes a solar water source heat pump system. Although it realizes the utilization of renewable energy, it still has significant technical bottlenecks: First, the efficiency of solar thermal collection is highly geographically dependent. Taking the typical area of ​​40° north latitude as an example, the effective thermal collection time in winter accounts for only 32.7% of the available daytime period, and the thermal collection efficiency decays by more than 62% under cloudy conditions; second, when using water medium for heat storage, its volumetric heat storage density is only 18%-27% of that of typical phase change materials such as sodium acetate trihydrate, resulting in the volume of the heat storage device generally exceeding the 17.5%-21% specified in the design specifications for building equipment rooms; third, the system has obvious thermal inertia characteristics, and the measured temperature control response delay is as long as 45-92 minutes, which makes it difficult to meet the rapid peak regulation needs under the time-of-use electricity price mechanism.

[0004] To overcome these limitations, the ground-source heat pump hybrid system proposed in patent document CN218915073U, while utilizing buried pipe heat exchangers to increase heat storage density, presents new technical challenges. First, the construction cost of the underground vertical pipes accounts for a staggering 41.3% of the total investment. In granite geological areas, the increased drilling difficulty increases the unit cost by 82%. Second, the system's coefficient of performance (COP) decays exponentially with underground heat accumulation, with the heat pump unit efficiency decreasing by 12.7%-18.3% after 36 months of continuous operation. Third, using R410A refrigerant, with its global warming potential (GWP) of 2088, results in an annual leakage of 1.5kg per 100kW unit, resulting in equivalent CO2 emissions of 3.13 tons. More importantly, the system's equipment footprint to energy supply area ratio is 1:3.2, limiting its application in urban core areas with floor area ratios greater than 3.5.

[0005] An analysis of technical pain points reveals that existing renewable energy supply systems are plagued by three-dimensional technical constraints: In terms of energy efficiency, fluctuations in environmental parameters cause fluctuations in the system's overall energy efficiency ratio (EER) by as much as ±18%. In terms of regulation, a lack of predictive control strategies based on multi-source heterogeneous data fusion leads to equipment startup and shutdown response times exceeding the grid dispatch cycle (15 minutes). In terms of space, the contradiction between equipment volume density and building functional space is prominent. The volume modulus of underground thermal storage devices reaches 0.85 m³ / kW, far exceeding the urban underground space development intensity standard. In particular, when participating in grid ancillary services, the existing system's power regulation rate is less than 0.4 Hz, making it unable to adapt to the second-level load tracking requirements of the virtual power plant (VPP) architecture. This has become a core technical obstacle to deep decarbonization in the building sector.

[0006] The information disclosed in this background technology section is only used to deepen the understanding of the background technology of the present disclosure and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0007] In view of at least one of the above technical problems, the present disclosure provides a heating system based on phase change energy storage combined with air source heat pump, which aims to solve the problems of high investment cost and harsh geological requirements of traditional heating systems, as well as discontinuous and unstable operation due to power supply fluctuations.

[0008] According to one aspect of the present disclosure, a heating system based on phase change energy storage combined with an air source heat pump is provided, comprising: An air-cooled heating unit connected to the user-side floor heating pipe coil to form a heating circuit.

[0009] A phase-change water storage tank connected to the air-cooled heating unit forms a heat storage circuit. The phase-change water storage tank is equipped with a phase-change material with a temperature higher than the operating temperature of the air-cooled heating unit, a spiral coil heat medium water pipeline and a phase-change water storage pump. The phase-change water storage tank is connected to the user-end floor heating pipe coil through a heat release branch.

[0010] Control module, the control module according to the power supply P 供电 User heat load Q 用户 The dynamic relationship between the heating system and the valves and pumps is controlled to switch the following modes: a. When P 供电 ≥( Q 用户 + Q 蓄热箱max ) / COP, the full load thermal storage mode is started.

[0011] b. When Q用户 / COP< P 供电＜ ( Q 用户 + Q 蓄热箱max ) / COP, start partial heat storage mode.

[0012] c. When P 供电 = Q 用户 / COP, the heat preservation mode is activated.

[0013] e.when P 供电 < Q 用户 / COP, start the combined heating mode.

[0014] d. When P 供电 When ≈0, the heat storage heating mode is started.

[0015] in, COP It is the energy efficiency ratio of the system, that is, the ratio of heating capacity to power supply.

[0016] In some embodiments of the present disclosure, the air-cooled heating unit includes an evaporator and its supporting fan, a condenser and its supporting fan and a compressor, a first liquid inlet pipeline and a first liquid return pipeline are connected between the evaporator and its supporting fan and the condenser and its supporting fan, a four-way valve is provided on the first liquid inlet pipeline, which is connected to the compressor through a compression liquid inlet pipeline and a compression liquid return pipeline, an expansion valve and a first solenoid valve are provided on the first liquid return pipeline, a second liquid inlet pipeline and a second liquid return pipeline are connected between the condenser and its supporting fan and the user-end floor heating pipe coil, and a second solenoid valve and a hot water pump are provided on the second liquid inlet pipeline.

[0017] In some embodiments of the present disclosure, the heat storage circuit includes a heat storage liquid inlet branch and a heat storage liquid return branch, the second liquid inlet pipeline is connected to the phase change water storage tank through the heat storage liquid inlet branch, a third solenoid valve is provided on the heat storage liquid inlet branch, and the second liquid return pipeline is connected to the phase change water storage tank through the heat storage liquid return branch.

[0018] In some embodiments of the present disclosure, a fourth solenoid valve, a check valve and a heat-releasing water pump are provided on the heat-releasing branch circuit.

[0019] In some embodiments of the present disclosure, the user-end floor heating pipe coil is a capillary network structure with a pipe diameter of 3-5 mm and a laying spacing of 80-120 mm, and is designed with the same pipe diameter as the spiral coil of the phase change water storage tank.

[0020] In some embodiments of the present disclosure, the phase change material is an organic fatty acid complex with a phase change temperature of 42~44°C and a latent heat value ≥190 kJ / kg, and the components include tristearin (45%-55%), tripalmitin (30%-40%) and trimyristin (10%-20%).

[0021] In some embodiments of the present disclosure, the method for constructing a heating system based on phase change energy storage combined with an air source heat pump includes: (1) Selection of air-cooled heating unit: Based on the total heat consumption M0 of the target building, M 0 ≤80% of the rated heating capacity of the unit.

[0022] (2) Phase change water storage tank selection: based on the duration of extreme operating conditions of power supply fluctuations t , combined with the latent heat value of the phase change material h and density ρ , calculate the volume V of the thermal storage tank using the following formula: .

[0023] Where Q0 is the theoretical heat consumption per unit time during the building's peak electricity consumption period, and ε is the energy storage efficiency, which is between 60% and 80%.

[0024] (3) Water pump selection: based on the total resistance Δ of the heat release branch P and traffic q , with Δ P The water pump is selected for safety redundancy of ×1.2, and the specific friction resistance of the hot water system is required to be controlled within a reasonable range of 80~120Pa / m. The calculation formula for the specific friction resistance is as follows: .

[0025] Where, d is the pipe diameter, and C is the Hessian-Williams coefficient (C=120 for closed steel pipe system and C=100 for open system).

[0026] In some embodiments of the present disclosure, the control method of the temperature control system based on phase change energy storage and air source heat pump includes: When in full-load heat storage mode, the first solenoid valve, the second solenoid valve and the third solenoid valve are opened, the fourth solenoid valve is closed, and the expansion valve is fully opened; In the partial load heat storage mode, the first solenoid valve is opened, the second solenoid valve is opened, the third solenoid valve is partially opened, the fourth solenoid valve is closed, and the expansion valve is fully opened; In heat preservation mode, the first solenoid valve is opened, the second solenoid valve is opened, the third solenoid valve and the fourth solenoid valve are closed, and the expansion valve is fully opened; When in combined heating mode, the first solenoid valve, the second solenoid valve and the fourth solenoid valve are opened, the third solenoid valve is closed, and the expansion valve is partially opened; When in the heat storage heating mode, only the fourth solenoid valve is opened, and the first solenoid valve, the second solenoid valve, the third solenoid valve and the expansion valve are closed.

[0027] In some embodiments of the present disclosure, in the combined heating mode, the heat supply of the heat storage tank is adjusted in real time by the PID algorithm, and the objective function is: min| Q 用户 −( COP × P 供电 + Q 蓄热 )∣; adjustment cycle ≤10s.

[0028] One or more technical solutions provided in the embodiments of this application have at least any of the following technical effects or advantages: 1. By combining an air-cooled heating unit with a phase-change water storage tank, the two complement and collaborate, improving the unit's power flexibility and its ability to cope with power supply fluctuations. Furthermore, the active heat storage in the phase-change water storage tank and the passive heat storage in the user-side floor heating coils effectively extend the system's heating time, enhancing the system's reliability and stability.

[0029] 2. By selecting a phase change material (organic fatty acid complex) with a higher operating temperature than the air-cooled heating unit, the air-cooled heating unit can be used to directly charge the phase change material, ensuring the normal operation of the air-cooled heating unit while not adding any additional volume to the heat storage tank. Furthermore, the phase change heat storage tank adopts an open structure, which facilitates the replacement of phase change materials with different phase change temperatures within the tank and also facilitates the inspection of the phase change material's condition within the tank. This also reduces the manufacturing difficulty and cost of the phase change heat storage tank. The heat transfer water flows within the heat transfer water pipeline without contact with the external environment, effectively preventing contamination of the heat transfer water and blockage of the heat transfer water pipeline.

[0030] 3. By setting multiple modes and combining the user's power supply status, the system operation strategy is optimized to meet user needs, ensuring that the heating system can operate efficiently under different power supply conditions, and achieving energy conservation and emission reduction during the operation stage of the air-cooled heating unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a system principle diagram of a temperature control system in one embodiment of the present application.

[0032] Figure 2 This is a diagram of the internal structure of a phase change water storage tank in one embodiment of the present application.

[0033] Figure 3 This is a left view of a phase-change water storage tank in one embodiment of the present application.

[0034] Figure 4 This is a top view of a phase-change water storage tank in one embodiment of the present application.

[0035] Figure 5 This is an operating logic diagram of the system working mode in one embodiment of the present application.

[0036] In the above figures, 1 is the user-end floor heating pipe coil, 2 is the evaporator, 3 is the condenser, 4 is the compressor, 5 is the four-way valve, 6 is the expansion valve, 7 is the first solenoid valve, 8 is the second solenoid valve, 9 is the hot water supply pump, 10 is the phase change water storage tank, 11 is the third solenoid valve, 12 is the phase change material, 13 is the heat medium water pipeline, 14 is the fourth solenoid valve, 15 is the check valve, and 16 is the heat release water pump. DETAILED DESCRIPTION

[0037] In the description of this application, it should be understood that the terms "upper," "lower," "front," "back," "left," "right," "top," "bottom," "inside," "outside," "vertical," "horizontal," "clockwise," "counterclockwise," and the like, indicating positions or locations, are based on the positions or locations shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Unless otherwise specified, the terms "connection" and "coupling" referred to in this application include both direct and indirect connections (couplings).

[0038] Unless otherwise specified, the unit modules, components, structures, mechanisms, sensors and other devices involved in the following embodiments are conventional commercially available products.

[0039] The present application discloses a heating system based on phase change energy storage combined with an air source heat pump, which aims to solve the problems of high investment cost and strict geological requirements of traditional heating systems, as well as discontinuous and unstable operation due to power supply fluctuations.

[0040] The technical solution in the embodiments of the present application is to solve the above problems. The overall idea is as follows: by combining an air-cooled heating unit and a phase-change water storage tank, the flexibility of the system's electricity consumption is improved and the problem of power supply fluctuations is solved; multiple power supply modes are set according to user needs, while meeting user needs and solving the problem of discontinuity and instability of the heating system when the power supply fluctuates.

[0041] In order to better understand the technical solution of the present application, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0042] Example 1 This example discloses a heating system based on phase change energy storage combined with air source heat pump, such as Figure 1 Shown, including: An air-cooled heating unit connects to the user-side floor heating coil 1 to form a heating circuit. This unit offers high energy efficiency, a high energy efficiency ratio, excellent low-temperature heating performance, high comfort, easy installation, reduced greenhouse gas emissions, and energy and resource conservation. It also boasts low operating costs and a long service life. Compared to traditional radiators, floor heating coils offer energy-saving and comfortable indoor comfort, uniform temperature, and minimal floor space occupation. They also passively store energy, allowing continued heating during power outages or when the air-cooled heating unit shuts down, extending heating time and improving system reliability and stability.

[0043] The air-cooled heating unit includes an evaporator 2 and its associated fan, a condenser 3 and its associated fan, and a compressor 4. A first liquid inlet line and a first liquid return line are connected between the evaporator 2 and its associated fan, and the condenser 3 and its associated fan. These first liquid inlet and first liquid return lines circulate the medium in the evaporator 2 between the evaporator and condenser 3. Preferably, the medium in the evaporator 1 is a refrigerant. A four-way valve 5 is provided on the first liquid inlet line, connected to the compressor 4 via a compression liquid inlet line and a compression liquid return line. An expansion valve 6 and a first solenoid valve 7 are provided on the first liquid return line. The first solenoid valve 7 controls the opening and closing of the first liquid return line. The expansion valve 6 is an electronic expansion valve that controls the flow of the medium in the first liquid return line, thereby controlling the operating load of the air-cooled heating unit. A second liquid inlet and second liquid return line are connected between the condenser 3 and its associated fan and the user-end floor heating coil 1. These second liquid inlet and second liquid return lines circulate the medium in the condenser 3 between the user-end floor heating coil 1 and the condenser 3 and its associated fan. Preferably, the medium in the condenser 3 is thermal water. A second solenoid valve 8 and a hot water pump 9 are provided on the second liquid inlet line. The second solenoid valve 8 is responsible for controlling the on / off state of the second liquid inlet line. The hot water pump 9 increases the pressure of the medium, promoting its flow and achieving rapid heating.

[0044] The phase-change water storage tank 10 is connected to the air-cooled heating unit to form a heat storage circuit. The excess energy of the air-cooled heating unit is stored in the phase-change water storage tank 10 through the heat storage circuit, thereby reducing unnecessary energy waste. The heat storage circuit includes a heat storage liquid inlet branch and a heat storage liquid return branch. The second liquid inlet pipeline is connected to the phase-change water storage tank through the heat storage liquid inlet branch, and the second liquid return pipeline is connected to the phase-change water storage tank through the heat storage liquid return branch. When the medium flows through the second liquid inlet pipeline and the second liquid return pipeline to heat the user-end floor heating coil, the excess heat energy is transferred to the phase-change water storage tank 10 through the heat storage liquid inlet branch and the heat storage liquid return branch for storage. A third solenoid valve 11 is provided on the heat storage liquid inlet branch, which is responsible for controlling the on and off of the heat storage liquid inlet branch.

[0045] like Figure 2 、 3 As shown in Figures 4 and 5, the phase-change water storage tank 10 contains a phase-change material 12 with a temperature higher than the operating temperature of the air-cooled heating unit, a spiral coil heat medium water pipeline 13, and a phase-change water storage pump. The phase-change material 12 is used to store energy. Considering that the maximum return water temperature of the air-cooled heat pump unit in winter is 45°C, a phase-change material 12 with a phase-change temperature lower than the maximum return water temperature of the air conditioner is selected to directly utilize the air-cooled heating unit for energy storage. This ensures that the phase-change material 12 inside the phase-change water storage tank 10 is completely liquefied during heat storage. Phase-change heat storage promotes the flow of the medium in the phase-change water storage tank 10, increasing the flow rate and achieving rapid heat storage. Preferably, the medium in the phase change water storage tank 10 is heat transfer water. The heat transfer water flows in the heat transfer water pipeline 13 in the phase change water storage tank 10 and is connected to the user-end floor heating pipe disc 1 through a heat release branch, so that the heat energy stored in the phase change water storage tank 10 is transferred to the user-end floor heating pipe disc 1 in the form of heat transfer water, which can improve the flexibility of the electricity demand of the air-cooled heating unit.

[0046] The shell of the phase-change water storage tank 10 is preferably made of 304 stainless steel, with an open top and removable lid for easy filling of the phase-change material 12. A drain port is provided at the bottom of the phase-change water storage tank to drain the phase-change material, facilitating replacement of phase-change material 12 with different phase-change temperatures. The steel plate of the phase-change water storage tank 10 is coated with insulation material to reduce heat loss. This insulation material is wrapped with a layer of polished aluminum foil to reduce radiative heat dissipation. Openings are located on the upper and lower sides of the right side of the phase-change water storage tank 10, connected to manifolds, allowing air-conditioning water to flow in and out of the tank 10. Each manifold is connected to a flexible coil within the tank that folds vertically. The phase-change material 12 is stored within the shell of the phase-change water storage tank 10, and the air-conditioning water can flow through the manifolds within the coils within the tank. The heat medium water pipeline in the phase change water storage tank 10 adopts a corrugated pipe, which can increase the heat exchange area and enhance the heat exchange effect between the air-conditioning water in the pipe and the phase change material 12 in the water tank.

[0047] The phase-change heat storage tank 10 is connected to the user-side floor heating coil 1 via a heat release branch. The heat energy stored in the phase-change heat storage tank is directly provided to the user via the heat release branch. When the air-cooled heating unit is affected by power supply fluctuations, the phase-change heat storage tank 10 can provide supplemental heat. This increases the flexibility of the air-cooled heating unit's electricity demand, allowing the air-cooled heating unit to cope with power supply fluctuations, improving the unit's energy efficiency and thus reducing the heating system's operational carbon emissions. The heat release branch is equipped with a fourth solenoid valve 14, a check valve 15, and a heat release pump 16. The fourth solenoid valve 14 controls the opening and closing of the heat release branch for easy control; the check valve 15 prevents backflow of the medium in the heat release branch, improving flow efficiency; and the heat release pump 16 accelerates the flow of the medium in the heat release branch, increasing flow rate and achieving rapid heat release. Compared to traditional energy storage, phase-change heat storage technology offers greater energy storage capacity and higher energy storage efficiency. By using phase-change energy storage equipment to store excess energy from the air-cooled heating unit, energy waste is reduced and economic benefits are improved.

[0048] Control modules such as Figure 5 As shown, the control module is based on the power supply P 供电 User heat load Q 用户 The dynamic relationship between the heating system and the valves and pumps is controlled to switch the following modes: a. when P 供电 ≥( Q 用户 + Q 蓄热箱max ) / COP, that is, the power supply is greater than or equal to the total power demand of the user's heat load and the phase change water storage tank's full-load heat storage; the full-load heat storage mode is started.

[0049] b. When Q 用户 / COP< P 供电＜ ( Q 用户 + Q 蓄热箱max ) / COP, that is, the power supply is less than the total power demand of the user's heat load plus the phase change thermal storage tank at full load, but it is still greater than the user's heat load; the partial heat storage mode is started.

[0050] c. When P 供电 = Q 用户 / COP, that is, the power supply is equal to the power demand of the user's heat load; the heat preservation mode is activated.

[0051] d. When P 供电 < Q用户 / COP, that is, the power supply is less than the power demand of the user's heat load; the combined heating mode is started.

[0052] e. when P 供电 When ≈0, the power supply is tight; the heat storage heating mode is started. COP It is the energy efficiency ratio of the system, that is, the ratio of heating capacity to power supply.

[0053] Furthermore, the user-end floor heating pipe plate is a capillary network structure with a pipe diameter of 3-5 mm and a laying spacing of 80-120 mm.

[0054] Example 2 Based on the first embodiment, this embodiment further optimizes and discloses a method for selecting and calculating a temperature control system based on a phase change energy storage coupled with an air source heat pump, including: (1) Heat pump unit selection First determine the total heat consumption M0 of the target building, then determine the total load of the air source heat pump system to meet M 0 ≤80% of the rated heating capacity of the unit. Taking a three-story office building as an example, first determine the total heat consumption M0 of the target building to be 57kw, then select the air-cooled heating unit model MAC210DRS to meet the heat consumption.

[0055] (2) Phase change thermal storage tank selection: The theoretical heat consumption per unit time, Q0, can be derived from the temperature change during the building's peak electricity consumption period (T1-T2). Unlike large-scale thermal storage equipment that can cope with long power outages, the main purpose of this invention is to improve the real-time power flexibility of the air source heat pump system. Therefore, the selection calculation is based on the most unfavorable operating condition of 120 minutes of severe power shortage. The calculation is performed using the following formula: ; The thermal storage material of this embodiment is a phase change material (organic fatty acid composite phase change material, the main components of which are tristearin, tripalmitin, and trimyristin) with a phase change latent heat cPCM of 190 kJ / kg and a phase change temperature of 43°C. This thermal storage material has the advantages of being safe and non-toxic, having a suitable phase change temperature, a large phase change potential, and a low price.

[0056] According to the duration of extreme working conditions of power supply fluctuation t , combined with the latent heat value of the phase change material h and density ρ The mass of phase change material and volume of phase change water tank required for continuous heating for 120 minutes are calculated using the following formula, and the detailed calculation process is as follows: ; Where ρ is the density of the phase change material, kg / m 3 ; V is the volume of the phase change material, m 3 h is the phase change latent heat of the phase change material (kJ / kg); Q0 is the theoretical heat consumption per unit time during the building's peak electricity consumption period; t is the duration of the extreme operating condition; ε is the energy storage efficiency, which is 60% to 80%. The extreme operating condition duration t is dynamically adjusted based on the grid demand response signal, and a 10%-15% safety margin is added to the thermal storage tank volume V.

[0057] (3) Water pump selection: Based on the total resistance Δ of the heat release branch P and traffic q , with Δ P The water pump is selected with a safety margin of ×1.2. In this embodiment, taking the heat release branch water pump as an example, the water resistance of the floor heating coil in the most unfavorable loop is 15kPa, and the flow rate is 1278kg / h. The resistance of the connecting pipe between the surface cooler and the water coil in the phase change tank is calculated using conventional flow resistance calculation methods. According to Article 5.8.3 of the "National Civil Building Engineering Design Technical Measures", the specific friction resistance of the hot water system must be controlled within a reasonable range of 80-120Pa / m. The specific friction resistance calculation formula is as follows: ; Where, d is the pipe diameter, q is the flow rate, C is the Hessian-Williams coefficient, C=120 for the closed steel pipe system and C=100 for the open system.

[0058] According to the formula for specific friction resistance and the required range of specific friction resistance, the range of pipe diameters is deduced. DN15 is selected as the main pipe size, with a specific friction resistance of 214 Pa / m, which meets the technical requirements. The maximum length of the water pipe is 15 m; the equivalent length of 4 elbows is 2 m; the valve loss is 5.5 m; and the total loss is 4.815 kPa.

[0059] The water coils in the phase change water tank are connected in parallel with multiple water channels. Based on the resistance calculation for the parallel pipes, a three-way pipe was selected, with a specific friction resistance of 201 Pa / m, meeting the technical requirements. A single pipe length of 5 m was chosen. Eleven elbows were calculated, with the equivalent length of the three-way 180° elbow being 0.8 m, for a total of 8.8 m. The equivalent length of the parallel pipe tee was 2 m. The total loss was 3.175 kPa. The total water resistance of the water loop was 22.99 kPa.

[0060] The formula for calculating water pump power consumption is as follows. The design pressure head and design flow rate are usually selected based on 80% of the nameplate value: ; Based on the above calculation results, the appropriate model of water pump can be selected to build the system according to the overall water resistance of the water loop, i.e. the head, and the water pump power consumption, i.e. the power.

[0061] It's worth noting that, on the one hand, the actual operation of an air-source heat pump system doesn't involve continuous heating at the end. That is, once the indoor temperature reaches the user's set point, the air-source heat pump system stops heating. Therefore, a phase-change thermal storage tank selected based on a 15-minute continuous heating schedule will actually provide heating for significantly longer than 15 minutes. On the other hand, the selection calculations were based on the extreme operating condition of complete cooling provided by the thermal storage tank. Therefore, if the system is used as a supplemental heating device during power outages, the dimensions of the thermal storage tank, water pump, and other key components will be significantly reduced.

[0062] Example 3 Further optimizing the technology of Example 1, this embodiment discloses a control method for a temperature control system based on a phase change energy storage coupled with an air source heat pump, including: In full-load heat storage mode, the heating load of the user-side floor heating coil 1 is entirely borne by the air-cooled heating unit. After absorbing heat in the evaporator 2 and its supporting fan, the refrigerant enters the first liquid inlet pipeline. Under the action of the four-way valve 5, it flows through the compressor 4 through the compression liquid inlet pipeline and the compression return liquid pipeline. After the refrigerant passes through the compressor 4 and becomes a high-temperature and high-pressure refrigerant, it enters the condenser 3 and its supporting fan through the four-way valve 5 to release heat. Open the first solenoid valve 7 and fully open the expansion valve 6. After releasing heat, the refrigerant returns to the evaporator 2 and its supporting fan through the first return liquid pipeline in the form of low temperature and low pressure under the action of the expansion valve 6. Open the second solenoid valve 8. After the heat medium water in the condenser 3 and its supporting fan is heated by the refrigerant in the evaporator 2 and its supporting fan, it enters the user-side floor heating coil 1 through the second liquid inlet pipeline under the action of the hot water pump 9 to flow and supply heat. The heat medium water returns to the condenser 3 and its supporting fan through the second return liquid pipeline. The third solenoid valve 11 is fully opened, and the phase change water storage tank is in a full-load heat storage state; the heat medium water in the condenser 3 and its supporting fan enters the heat medium water pipeline 13 in the phase change water storage tank 10 through the heat storage liquid inlet branch, and the excess heat energy is transferred and stored in the phase change material 12. The heat medium water returns to the condenser 3 and its supporting fan through the heat storage liquid return branch.

[0063] In partial load heat storage mode, the heating load of the user-side floor heating coil 1 is entirely borne by the air-cooled heating unit. After absorbing heat in the evaporator 2 and its supporting fan, the refrigerant enters the first liquid inlet pipeline. Under the action of the four-way valve 5, it flows through the compression liquid inlet pipeline and the compression return liquid pipeline through the compressor 4. After the refrigerant passes through the compressor 4 and becomes a high-temperature and high-pressure refrigerant, it enters the condenser 3 and its supporting fan through the four-way valve 5 to release heat. The first solenoid valve 7 is opened and the expansion valve 6 is fully opened. The refrigerant after releasing heat returns to the evaporator 2 and its supporting fan through the first return liquid pipeline in the form of low temperature and low pressure under the action of the expansion valve 6. The second solenoid valve 8 is opened. After the heat medium water in the condenser 3 and its supporting fan is heated by the refrigerant in the evaporator 2 and its supporting fan, it enters the user-side floor heating coil 1 through the second liquid inlet pipeline under the action of the hot water pump 9 to flow and provide heat. The heat medium water returns to the condenser 3 and its supporting fan through the second return liquid pipeline. The third solenoid valve 11 is partially opened, and the phase change energy storage device is in a partial load heat storage state; the heat medium water in the condenser 3 and its supporting fan enters the heat medium water pipeline 13 in the phase change water storage tank through the heat storage liquid inlet branch, and the excess heat energy is transferred and stored in the phase change material 12, and the heat medium water returns to the condenser 3 and its supporting fan through the heat storage liquid return branch.

[0064] In heat preservation mode, the cooling load of the user-side floor heating coil 1 is entirely borne by the air-cooled heating unit. After absorbing heat in the evaporator 2 and its supporting fan, the refrigerant enters the first liquid inlet line. Under the action of the four-way valve 5, it flows through the compression liquid inlet line and the compression return liquid line through the compressor 4. After the refrigerant passes through the compressor 4 and becomes a high-temperature and high-pressure refrigerant, it enters the condenser 3 and its supporting fan through the four-way valve 5 to release heat. The first solenoid valve 7 is opened and the expansion valve 6 is fully opened. The refrigerant, after releasing heat, returns to the evaporator 2 and its supporting fan through the first return liquid line in the form of low temperature and low pressure under the action of the expansion valve 6. The second solenoid valve 8 is opened. After the heat transfer water in the condenser 3 and its supporting fan is heated by the refrigerant in the evaporator 3 and its supporting fan, it enters the user-side floor heating coil 1 through the second liquid inlet line under the action of the hot water pump 8 to flow and provide heat. The heat transfer water returns to the condenser 3 and its supporting fan through the second return liquid line. The phase change water storage tank 10 is in a heat preservation state.

[0065] In combined heating mode, the heating load of the user-side floor heating coil 1 is shared by the air-cooled heating unit and the phase-change water storage tank 10. After absorbing heat in the evaporator 2 and its supporting fan, the refrigerant enters the first liquid inlet line. Under the action of the four-way valve 5, it flows through the compression liquid inlet line and the compression return line through the compressor 4. After being converted into high-temperature and high-pressure refrigerant by the compressor, the refrigerant then enters the condenser 3 and its supporting fan through the four-way valve 5 to release heat. The first solenoid valve 7 is opened, and the expansion valve 6 is partially opened. After releasing heat, the refrigerant returns to the evaporator 2 and its supporting fan through the first return line at low temperature and low pressure under the action of the expansion valve 6. The second solenoid valve 8 is opened, and the heat transfer water in the condenser 3 and its supporting fan is heated by the refrigerant in the evaporator 2 and its supporting fan. Then, under the action of the hot water pump 9, it enters the user-side floor heating coil through the second liquid inlet line to flow and provide heat. The heat transfer water returns to the condenser 3 and its supporting fan through the second return line. The fourth solenoid valve 14 and the check valve 15 are opened automatically. The heat medium water in the phase change water storage tank 10 carries the heat energy stored in the phase change material 12 and enters the user-end floor heating pipe plate 1 through the heat release liquid inlet branch under the action of the heat release water pump 16 for circulation heating. The heat medium water returns to the phase change water storage tank 10 through the heat storage return liquid branch.

[0066] In thermal storage heating mode, the heating load of the user-side floor heating coil 1 is entirely borne by the phase-change water storage tank 10. The fourth solenoid valve 14 is opened, and the check valve 15 automatically opens. The thermal water in the phase-change water storage tank 10 absorbs the heat energy stored in the phase-change material 12 in the thermal water pipeline. Driven by the heat-dissipating water pump 16, the thermal water enters the user-side floor heating coil 1 through the heat-dissipating liquid inlet branch for a heating cycle. The thermal water then returns to the phase-change energy storage device through the heat-dissipating liquid return branch.

[0067] Although some preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0068] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the inventive concept. Thus, if such modifications and variations of the present disclosure fall within the scope of the claims and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A heating system based on phase change energy storage combined with air source heat pump, characterized in that: include: An air-cooled heating unit connected to the user-side floor heating coil to form a heating circuit; A phase-change water storage tank connected to the air-cooled heating unit to form a heat storage loop. The phase-change water storage tank contains a phase-change material with a higher operating temperature than the air-cooled heating unit, a spiral coil heat medium water pipeline, and a phase-change water storage pump. The phase-change water storage tank is connected to the user-end floor heating coil via a heat release branch. Control module, used to adjust the power supply P 供电 User heat load Q 用户 Dynamic relationships to switch between the following modes: a.when P 供电 ≥( Q 用户 + Q 蓄热箱max ) / COP, start the full load heat storage mode; b. When Q 用户 / COP< P 供电＜ ( Q 用户 + Q 蓄热箱max ) / COP, start partial heat storage mode; c. When P 供电 = Q 用户 / COP, start the heat preservation mode; d. When P 供电 < Q 用户 / COP, start the combined heating mode; e.when P 供电 When ≈0, the heat storage heating mode is started; in, COP It is the energy efficiency ratio of the system, that is, the ratio of heating capacity to power supply.

2. The heating system based on phase change energy storage combined with air source heat pump according to claim 1 is characterized in that: The air-cooled heating unit includes an evaporator and its supporting fan, a condenser and its supporting fan and a compressor. A first liquid inlet pipeline and a first liquid return pipeline are connected between the evaporator and its supporting fan and the condenser and its supporting fan. A four-way valve is provided on the first liquid inlet pipeline, which is connected to the compressor through a compression liquid inlet pipeline and a compression liquid return pipeline. An expansion valve and a first solenoid valve are provided on the first liquid return pipeline. A second liquid inlet pipeline and a second liquid return pipeline are connected between the condenser and its supporting fan and the user-end floor heating pipe coil. A second solenoid valve and a hot water pump are provided on the second liquid inlet pipeline.

3. The heating system based on phase change energy storage combined with air source heat pump according to claim 2 is characterized in that: The heat storage circuit includes a heat storage liquid inlet branch and a heat storage liquid return branch. The second liquid inlet pipeline is connected to the phase change water storage tank through the heat storage liquid inlet branch. A third solenoid valve is provided on the heat storage liquid inlet branch. The second liquid return pipeline is connected to the phase change water storage tank through the heat storage liquid return branch.

4. The heating system based on phase change energy storage combined with air source heat pump according to claim 3 is characterized in that: The heat release branch is provided with a fourth electromagnetic valve, a check valve and a heat release water pump.

5. The temperature control system based on phase change energy storage and air source heat pump according to claim 4 is characterized in that: The user-end floor heating pipe coil is a capillary network structure with a pipe diameter of 3~5 mm and a laying spacing of 80~120 mm, and is designed with the same pipe diameter as the spiral coil of the phase change water storage tank.

6. The temperature control system based on phase change energy storage and air source heat pump according to claim 1 is characterized in that: The phase change material is an organic fatty acid complex with a phase change temperature of 42-44°C and a latent heat value of ≥190 kJ / kg. The components include 45%-55% tristearin, 30%-40% tripalmitin, and 10%-20% trimyristin.

7. The method for constructing a heating system based on phase change energy storage combined with an air source heat pump according to claim 1, characterized in that: include: (1) Selection of air-cooled heating unit: Based on the total heat consumption M0 of the target building, M 0 ≤80% of the rated heating capacity of the unit; (2) Phase change water storage tank selection: based on the duration of extreme operating conditions of power supply fluctuations t , combined with the latent heat value of the phase change material h and density ρ , calculate the volume V of the thermal storage tank using the following formula: ； Where Q0 is the theoretical heat consumption per unit time during the building's peak electricity consumption period, and ε is the energy storage efficiency, which is between 60% and 80%. (3) Water pump selection: based on the total resistance Δ of the heat release branch P and traffic q , with Δ P The water pump is selected for safety redundancy of ×1.2, and the specific friction resistance of the hot water system is required to be controlled within a reasonable range of 80~120Pa / m. The calculation formula for the specific friction resistance is as follows: ； Where, d is the pipe diameter, C is the Hessian-Williams coefficient, and C=100 for an open system.

8. The method for constructing a temperature control system based on a phase change energy storage coupled with an air source heat pump according to claim 5, characterized in that: In step (1), the total heat consumption of the building M 0 Determined through dynamic load simulation, it includes the correction value of the heat transfer coefficient of the enclosure structure, lighting density and personnel density fluctuation coefficient.

9. A control method for a temperature control system based on a phase change energy storage coupled with an air source heat pump according to claim 1, characterized in that: include: When in full-load heat storage mode, the first solenoid valve, the second solenoid valve and the third solenoid valve are opened, the fourth solenoid valve is closed, and the expansion valve is fully opened; In the partial load heat storage mode, the first solenoid valve is opened, the second solenoid valve is opened, the third solenoid valve is partially opened, the fourth solenoid valve is closed, and the expansion valve is fully opened; In heat preservation mode, the first solenoid valve is opened, the second solenoid valve is opened, the third solenoid valve and the fourth solenoid valve are closed, and the expansion valve is fully opened; When in combined heating mode, the first solenoid valve, the second solenoid valve and the fourth solenoid valve are opened, the third solenoid valve is closed, and the expansion valve is partially opened; When in the heat storage heating mode, only the fourth solenoid valve is opened, and the first solenoid valve, the second solenoid valve, the third solenoid valve and the expansion valve are closed.

10. The coordinated temperature control method according to claim 9, characterized in that: In the combined heating mode, the heat supply of the heat storage tank is adjusted in real time by the PID algorithm, and the objective function is: min| Q 用户 −( COP × P 供电 + Q 蓄热 )∣; adjustment cycle ≤10s.

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