A high-efficiency solar thermal collection system and control method based on heat pump technology

Abstract

The present invention belongs to the field of heat pump technology, and in particular, relates to a high-efficiency solar thermal collection system based on heat pump technology, specifically a solar heat pump thermal collection system and control method. The system of the present invention includes a heat pump subsystem and a solar thermal collection subsystem, and the two systems are connected through a thermal energy enhancer. The present invention optimizes the joint operation mode of the heat pump and the solar thermal collection subsystem according to the heat pump energy efficiency curve, ambient temperature, light intensity, etc., minimizes the heat loss of the collector, and uses the heat to increase the temperature of the evaporator heat exchange medium in the heat pump subsystem, thereby simultaneously improving the heat exchange efficiency of the solar thermal collection subsystem and the heat pump subsystem; adopts a slight energy increase rate, can absorb heat to the maximum extent following the changes in ambient temperature, sunlight intensity, etc., while reducing the overall solar thermal collection subsystem electric energy consumption; does not change the structure of the heat pump subsystem, simplifies the complexity of the combination of the solar thermal collection subsystem and the heat pump subsystem, and is flexible in design and debugging.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat pumps, and in particular relates to a high-efficiency solar heat collection system based on heat pump technology, specifically a solar heat pump heat collection system and a control method. Background Art

[0002] Solar energy can be utilized in two forms: photovoltaic and solar thermal. The COP (energy efficiency) of solar thermal is higher when the ambient temperature is high or the temperature difference between the heat exchange medium of the solar thermal collector and the ambient temperature is large. If the ambient temperature is low or the temperature difference between the heat exchange medium of the collector and the ambient temperature is small, the COP drops sharply.

[0003] The existing solar collector has a low COP when the temperature difference between the heat exchange medium and the ambient temperature is large, mainly because the large temperature difference causes the collector to dissipate more heat to the surrounding environment. The low COP of the heat pump in a low temperature environment is related to the small amount of heat that can be absorbed from the environment and the high power consumption. In addition, the existing solar energy combined with heat pump technology simply connects the solar collector panel and the evaporator in series, and converts the low-quality heat of the collector into high-quality heat for collection through the heat pump, without considering the problem of reducing the heat dissipation of the collector, and usually uses refrigerant heat exchange, which makes the cost higher, and also does not consider the energy consumption during operation.

[0004] Therefore, the disadvantages of solar energy such as low energy density and low efficiency restrict its further promotion and application in cold regions. Heat pumps have similar problems to solar thermal. When the ambient temperature is high or the temperature difference between the refrigerant temperature of the heat pump evaporator and the ambient temperature is large, the COP (energy efficiency) is high. If the ambient temperature is low or the temperature difference is small, the COP is low. Summary of the invention

[0005] In view of the shortcomings of the above-mentioned prior art, the present invention provides a high-efficiency solar thermal collection system and control method based on heat pump technology. The purpose is to simplify the complexity of combining the solar thermal collection subsystem with the heat pump subsystem without changing the structure of the heat pump subsystem, and to minimize the heat loss of the collector.

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0007] A high-energy-efficiency solar thermal collection system based on heat pump technology comprises a heat pump subsystem and a solar thermal collection subsystem, wherein the solar thermal collection subsystem is connected to an evaporator of the heat pump subsystem via a thermal energy amplifier.

[0008] Furthermore, the thermal energy enhancer includes a waste heat collector, an air preheater, or a heat collection device integrated in a heat pump subsystem or a solar thermal collection subsystem.

[0009] Furthermore, the evaporator includes an induced draft fan or a circulation pump, and the evaporator is an energy enhancer.

[0010] Furthermore, the solar thermal collection subsystem is an integrated system for heat collection and power generation, which is integrated into the evaporator in the heat pump subsystem through a thermal energy amplifier, thereby combining the solar thermal collection subsystem with the heat pump subsystem.

[0011] Furthermore, the heat pump subsystem is composed of a compressor, a condenser, an expansion valve, and an evaporator connected in sequence through pipelines; wherein the exhaust port of the compressor is connected to the primary side inlet of the condenser, the primary side outlet of the condenser is connected to the inlet of the expansion valve, the outlet of the expansion valve is connected to the heating chamber inlet of the evaporator, and the evaporation chamber outlet of the evaporator is connected to the suction port of the compressor, forming a closed-loop pipeline; the pipeline contains refrigerant.

[0012] Furthermore, the condenser is a shell-and-tube heat exchanger.

[0013] Furthermore, the solar thermal collection subsystem includes a hot water storage tank, a collector, an induced draft fan, a first electrically controlled valve, a second electrically controlled valve, a third electrically controlled valve, a first three-way valve, an air inlet, a temperature control switch, an air outlet, a second three-way valve, a third three-way valve, a heat exchanger, a heat exchanger and a second circulating water system; wherein the air outlet of the collector is connected to the inlet of the induced draft fan, the outlet of the induced draft fan is connected to the confluence of the third three-way valve, a branch port of the third three-way valve is connected to the primary side air duct inlet of the heat exchanger, and the outlet of the third three-way valve is connected to the confluence of the third three-way valve. Another branch port is connected to the primary side air duct inlet of the evaporator; the primary side air duct outlet of the heat exchanger and the primary side air duct outlet of the evaporator are connected to the second three-way valve confluence port after confluence, one branch port of the second three-way valve is connected to the exhaust port, and the other branch port of the second three-way valve is connected to the inlet of the temperature control switch; the outlet of the temperature control switch is connected to the first three-way valve confluence port, one branch port of the first three-way valve is connected to the exhaust port, and the other branch port of the first three-way valve is connected to the air inlet of the collector to form a heat exchange air duct;

[0014] Among them, the first electric control valve, the second electric control valve, and the third electric control valve are connected in series, and after the wind ducts of the solar collector plates in the collector are connected in series in pairs, they are respectively connected in parallel with the first electric control valve, the second electric control valve, and the third electric control valve, and the on and off of the electric control valves are controlled as needed;

[0015] The inlet of the first circulating water pump is connected to the secondary side inlet of the condenser, and the outlet of the first circulating water pump is connected to the hot water storage tank; the secondary side outlet of the condenser is connected to the hot water storage tank to form a closed loop for heat storage;

[0016] The inlet of the second circulating water pump is connected to the secondary side inlet of the heat exchanger, and the outlet of the second circulating water pump is connected to the hot water storage tank; the secondary side outlet of the heat exchanger is connected to the hot water storage tank to form a closed loop for heat storage;

[0017] The third circulating water pump is connected to the outlet of the user, the outlet of the third circulating water pump is connected to the hot water storage tank, and the inlet of the user is connected to the hot water storage tank, forming a closed loop to supply heat to the user.

[0018] Furthermore, the heat exchanger is a finned heat exchanger; the heat exchanger and condenser are placed inside or outside the hot water tank for heat exchange; the user includes heating or floor heating.

[0019] A control method for a high-efficiency solar thermal collection system based on heat pump technology, including two operating states: independent operation and joint operation;

[0020] The independent operation refers to the operation of the solar thermal collector subsystem alone. First, the start and end time of the operation of the solar thermal collector subsystem is optimized, including: at noon when the sunlight is strong and the temperature is high, and the time period with the highest heat is selected for heat collection;

[0021] The joint operation refers to the joint operation of the heat pump and the thermal collector subsystem: the system operation time period is determined by the same method as the independent operation, the outlet temperature of the thermal energy enhancer is set according to user needs in combination with the ambient temperature, light intensity and the heat pump energy efficiency curve, and the speed and operation mode of the circulating heat exchange are adjusted according to the set temperature; when the amount of heat collected by the collector during the day does not meet the user's heat demand or the temperature of the hot water tank is quickly increased or when the ambient temperature is low, resulting in a low COP of the heat pump, the heat pump subsystem is operated jointly with the solar thermal collector subsystem.

[0022] Furthermore, the method for selecting the start and end time comprises the following steps:

[0023] Step 1. Calculate the user's heat demand;

[0024] The heat collected by the collector is calculated based on the ambient temperature, wind speed, and light intensity. The shortest time period for collecting heat to meet the user's heat demand is the start and end time of the solar thermal collection subsystem operation;

[0025] Step 2. Set the collector outlet temperature;

[0026] Set the collector outlet temperature according to the minimum heat dissipation of the collector system;

[0027] Step 3. According to the set collector outlet temperature, the series-parallel operation mode of the collector is changed by turning on and off the first, second and third electric-controlled valves, and the frequency conversion speed of the induced draft fan is controlled to change the heat exchange rate; when the first and third electric-controlled valves are turned on and the second electric-controlled valve is turned off, the collector is operated in series; when the first and second electric-controlled valves are turned on and the third electric-controlled valve is turned off, the collector is operated in parallel;

[0028] The joint operation includes the following steps:

[0029] Step (1) optimizing and selecting the start and end time of the operation of the solar thermal collection subsystem;

[0030] The optimization process is the same as that of independent operation, that is, the start and end time of the solar thermal collection subsystem operation is optimized according to the ambient temperature, wind speed and light intensity;

[0031] Step (2) setting the collector outlet temperature; based on the ambient temperature, wind speed, light intensity, and with reference to the heat pump energy efficiency curve, the collector outlet temperature value is set with the minimum energy consumption ratio of the collector system while meeting the user's thermal energy demand;

[0032] The solar collector subsystem and the heat pump subsystem are controlled separately. The solar collector subsystem controls the collector outlet temperature. If the collector outlet temperature rises, the wind speed of the induced draft fan is increased; otherwise, the wind speed of the induced draft fan is reduced. If the air temperature at the evaporator heat exchange outlet is lower than the ambient temperature, the heat exchanged air is directly discharged into the environment through the exhaust port, and the air heat exchange cycle is open-loop operation. If the air temperature at the evaporator heat exchange outlet is higher than the ambient temperature, the heat exchanged air is sent back to the collector through the temperature control switch, and the air heat exchange cycle is closed-loop operation.

[0033] The heat pump subsystem control is based on the heat pump heat increment rate, that is, the ratio dQ / dP of the heat pump subsystem heat collection increment ΔQ and the electric energy consumption increment ΔP. Specifically, the heat collection increment ΔQ of the heat exchanger is calculated by measuring the flow rate of the circulating water pump and the inlet and outlet water temperature difference, and dQ / dP is calculated by the corresponding heat pump electric energy consumption increment ΔP. When dQ / dP>0, the heat exchange rate of the heat pump is increased; when dQ / dP<0, the heat exchange rate of the heat pump is reduced.

[0034] Among them, d in the above formula represents the derivative, Q represents the heat, and P represents the energy consumption;

[0035] The collector outlet temperature and thermal energy booster outlet temperature values ​​are calculated by the optimization algorithm based on the optimization target set according to user needs;

[0036] Determine the series and parallel combination of the collector plates and the thermal energy enhancer in the collector subsystem according to the set values ​​of the collector outlet temperature and the thermal energy enhancer outlet temperature;

[0037] The solar energy collection subsystem adjusts the speed of the circulating heat exchange according to the set temperature, that is, if the temperature of the thermal energy booster increases, the flow speed of the heat exchange medium is increased; otherwise, the flow speed of the heat exchange medium is reduced;

[0038] The heat exchange rate of the heat pump subsystem is controlled according to the heat increment rate, which is the ratio of the heat collection increment to the corresponding energy consumption increment; the heat increment rate of the heat pump is measured, and when the heat increment rate of the heat pump subsystem is greater than zero, the heat exchange rate of the heat pump subsystem is increased; otherwise, the heat exchange rate of the heat pump subsystem is reduced.

[0039] The present invention has the following beneficial effects and advantages:

[0040] The present invention optimizes the joint operation of the heat pump and the solar thermal collection subsystem according to the heat pump energy efficiency curve, ambient temperature, light intensity, etc., minimizes the heat loss of the collector, and uses the heat to increase the temperature of the heat exchange medium of the evaporator in the heat pump subsystem, thereby simultaneously improving the heat exchange efficiency of the solar thermal collection subsystem and the heat pump subsystem; adopts a slight energy increase rate, can absorb heat to the maximum extent following the changes in ambient temperature, sunlight intensity, etc., while reducing the overall solar thermal collection subsystem electric energy consumption; does not change the structure of the heat pump subsystem, simplifies the complexity of the combination of the solar thermal collection subsystem and the heat pump subsystem, and is flexible in design and debugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0042] Figure 1 It is a structural schematic diagram of the present invention.

[0043] In the figure:

[0044] Compressor 1, condenser 2, expansion valve 3, evaporator 4, first circulating water pump 5, hot water storage tank 6, collector 7, induced draft fan 8, first electrically controlled valve 9, second electrically controlled valve 10, third electrically controlled valve 11, first three-way valve 12, air inlet 13, temperature control switch 14, air outlet 15, second three-way valve 16, third three-way valve 17, heat exchanger 18, second circulating water pump 19, third circulating water pump 20, user 21. DETAILED DESCRIPTION

[0045] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0046] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0047] Refer to the following Figure 1 The technical solutions of some embodiments of the present invention are described.

[0048] Example 1

[0049] The present invention is a high-efficiency solar thermal collection system based on heat pump technology. Figure 1 As shown, Figure 1 It is a structural schematic diagram of the present invention.

[0050] The system of the present invention includes two subsystems: a heat pump subsystem and a solar heat collection subsystem. The solar heat collection subsystem is connected to the evaporator of the heat pump subsystem via a heat energy enhancer. The heat energy enhancer can be a waste heat collector, an air preheater, or a heat collection device integrated in the heat pump subsystem and the solar heat collection subsystem. In this embodiment, the evaporator 4 includes an induced draft fan or a circulation pump to introduce heat in the heat energy enhancer to the evaporator.

[0051] The solar thermal collector subsystem is an integrated system of heat collection and power generation, namely PV / T. It is integrated into the evaporator in the heat pump subsystem through a thermal energy amplifier, combining the solar thermal collector subsystem with the heat pump subsystem. The solar thermal collector subsystem operates under negative pressure, reducing the amount of heat dissipated by the collector to the surrounding environment, and uses the heat to increase the temperature of the heat exchange medium of the heat pump, thereby improving its heat exchange efficiency. The heat pump subsystem and the solar thermal collector subsystem are jointly optimized to reduce operating energy consumption.

[0052] The heat pump subsystem is composed of a compressor 1, a condenser 2, an expansion valve 3, and an evaporator 4 connected in sequence through pipelines. Specifically, the exhaust port of the compressor 1 is connected to the primary side inlet of the condenser 2, the primary side outlet of the condenser 2 is connected to the inlet of the expansion valve 3, the outlet of the expansion valve 3 is connected to the heating chamber inlet of the evaporator 4, and the evaporation chamber outlet of the evaporator 4 is connected to the air intake of the compressor 1, forming a closed-loop pipeline with refrigerant in the pipeline.

[0053] The heat exchanger 18 and the condenser 2 are placed inside or outside the hot water storage tank 6 for heat exchange; by optimizing the operation of the heat pump subsystem and the solar heat collection subsystem, the heat dissipation of the system is reduced and the energy consumption is reduced.

[0054] The condenser 2 is a shell-and-tube heat exchanger; the evaporator 4 is an energy enhancer.

[0055] The solar thermal collection subsystem is composed of a hot water storage tank 6, a collector 7, an induced draft fan 8, a first electrically controlled valve 9, a second electrically controlled valve 10, a third electrically controlled valve 11, a first three-way valve 12, an air inlet 13, a temperature control switch 14, an air outlet 15, a second three-way valve 16, a third three-way valve 17, a heat exchanger 18, a heat exchanger 18, and a second circulating water 19. Specifically, the air outlet of the heat collector 7 is connected to the inlet of the induced draft fan 8, the outlet of the induced draft fan 8 is connected to the confluence port of the third three-way valve 17, one branch port of the third three-way valve 17 is connected to the inlet of the primary side air duct of the heat exchanger 18, and the other branch port of the third three-way valve 17 is connected to the inlet of the primary side air duct of the evaporator 4; the primary side air duct outlet of the heat exchanger 18 and the primary side air duct outlet of the evaporator 4 are connected to the confluence port of the second three-way valve 16 after confluence, one branch port of the second three-way valve 16 is connected to the exhaust port 15, and the other branch port of the second three-way valve 16 is connected to the inlet of the temperature control switch 14; the outlet of the temperature control switch 14 is connected to the confluence port of the first three-way valve 12, one branch port of the first three-way valve 12 is connected to the exhaust port 15, and the other branch port of the first three-way valve 12 is connected to the air inlet of the heat collector 7, so as to form a heat exchange air duct;

[0056] The first electrically controlled valve 9, the second electrically controlled valve 10, and the third electrically controlled valve 11 are connected in series. After the four solar collector air ducts in the collector 7 are connected in series in pairs, they are respectively connected in parallel with the first electrically controlled valve 9, the second electrically controlled valve 10, and the third electrically controlled valve 11 to control the on and off of the electrically controlled valves as needed.

[0057] The heat exchanger 18 is a finned heat exchanger.

[0058] The inlet of the first circulating water pump 5 is connected to the secondary side inlet of the condenser 2, and the outlet of the first circulating water pump 5 is connected to the hot water storage tank 6; the secondary side outlet of the condenser 2 is connected to the hot water storage tank 6, forming a closed loop for heat storage. The hot water storage tank 6, the heat exchanger 18, and the second circulating water pump 19 are connected in the same manner as the first circulating water pump 5, the condenser 2, and the hot water storage tank 6; the inlet of the third circulating water pump 20 is connected to the outlet of the user 21, the outlet of the third circulating water pump 20 is connected to the hot water storage tank 6, and the inlet of the user 21 is connected to the hot water storage tank 6, forming a closed loop to supply heat to the user.

[0059] The user 21 includes heating, floor heating, etc.

[0060] The heat pump subsystem and the solar thermal collection subsystem can be operated independently or in combination.

[0061] In specific implementation, when the solar thermal collection subsystem has high energy efficiency and meets the heat demand of the user 21, the solar thermal collection subsystem operates independently. When the solar thermal collection subsystem operates independently, according to the heat demand of the user 21, with reference to the historical data of operation, combined with the predicted temperature and light intensity, etc., the time period with the highest heat collection efficiency is selected for heat collection; the collector outlet temperature is set according to the user's needs, and the frequency conversion technology is used to optimize the operation.

[0062] When the solar thermal collector subsystem has low energy efficiency and cannot meet the user's heat demand or quickly increases the temperature of the heat storage tank or when the ambient temperature is low, resulting in a low COP of the heat pump, the heat pump subsystem and the solar thermal collector subsystem are combined and operated together. That is, in conjunction with the heat pump energy efficiency curve, the comprehensive heat exchange efficiency of the two can be improved. The outlet temperature of the thermal energy booster can be reasonably set to optimize the operation of the solar thermal collector subsystem so that the heat collected by the thermal energy booster is output at the set temperature. This heat heats and increases the temperature of the evaporator heat exchange medium, minimizing the heat loss of the solar thermal collector subsystem, thereby improving the comprehensive heat exchange efficiency of the collector and heat pump.

[0063] In addition, the heat pump subsystem adopts a micro-energy increase rate, which can absorb heat to the maximum extent by following the heat changes of the thermal energy amplifier, while reducing the overall electrical energy consumption of the thermal collection system; without changing the structure of the heat pump subsystem, the complexity of the combination of the solar thermal collection subsystem and the heat pump subsystem is simplified, making the debugging and operation of this system flexible.

[0064] Example 2

[0065] The present invention is a control method for a high-efficiency solar thermal collection system based on heat pump technology, which specifically includes two operating states: independent operation and joint operation.

[0066] Joint operation of heat pump and heat collection subsystem: The same method as independent operation is used to determine the system operation time period, and the outlet temperature of the heat energy enhancer is set according to user needs in combination with ambient temperature, light intensity and heat pump energy efficiency curve. The speed and operation mode of the circulation heat exchange are adjusted according to the set temperature;

[0067] The independent operation generally refers to the solar thermal collection subsystem operating alone.

[0068] First, optimize the start and end time of the solar thermal collection subsystem, including: strong sunlight and high temperature at noon, choose the time period with the highest heat for heat collection.

[0069] The method for selecting the start and end time comprises the following steps:

[0070] Step 1. First, calculate the user's heat demand, and then calculate the heat collected by the collector 7 according to the ambient temperature, wind speed, and light intensity. The shortest time period for collecting heat to meet the user's heat demand is the start and end time of the solar heat collection subsystem operation;

[0071] Step 2. Next, set the outlet temperature of the heat collector 7. Set the outlet temperature of the heat collector 7 according to the minimum heat dissipation of the heat collection system;

[0072] Step 3. Finally, according to the set collector outlet temperature, the series-parallel operation mode of the collector 7 is changed by turning on and off the first electrically controlled valve 9, the second electrically controlled valve 10, and the third electrically controlled valve 11, and the frequency conversion speed of the induced draft fan is controlled to change the heat exchange rate; when the first electrically controlled valve 9 and the third electrically controlled valve 11 are turned on and the second electrically controlled valve 10 is turned off, the operation is in series; when the first electrically controlled valve 9 and the second electrically controlled valve 10 are turned on and the third electrically controlled valve 11 is turned off, the operation is in parallel.

[0073] The combined operation is to operate the heat pump subsystem and the solar thermal collection subsystem together when the heat collected by the collector 7 during the day does not meet the user's heat demand or the temperature of the hot water storage tank 6 is quickly increased or when the ambient temperature is low resulting in a low COP of the heat pump.

[0074] The specific process includes the following steps:

[0075] Step (1) first optimizes and selects the start and end times of the solar thermal collection subsystem operation.

[0076] The optimization process is the same as that of independent operation, that is, the start and end time of the solar thermal collection subsystem operation is optimized according to the ambient temperature, wind speed, light intensity, etc.;

[0077] Step (2) Next, set the outlet temperature of the heat collector 7. According to the ambient temperature, wind speed, light intensity, and with reference to the heat pump energy efficiency curve, the outlet temperature of the heat collector 7 is set to minimize the energy consumption ratio of the heat collection system while meeting the user's heat energy demand.

[0078] The solar heat collection subsystem and the heat pump subsystem are controlled separately. The solar heat collection subsystem controls the outlet temperature of the collector 7. If the outlet temperature of the collector 7 rises, the wind speed of the induced draft fan 8 is increased; otherwise, the wind speed of the induced draft fan 8 is reduced; if the air temperature at the heat exchange outlet of the evaporator 4 is lower than the ambient temperature, the air after heat exchange is directly discharged into the environment through the exhaust port 15, and the air heat exchange cycle is open-loop operation; if the air temperature at the heat exchange outlet of the evaporator 4 is higher than the ambient temperature, the air after heat exchange is sent back to the collector 7 through the temperature control switch 14, and the air heat exchange cycle is closed-loop operation.

[0079] The heat pump subsystem is controlled based on the heat increment rate of the heat pump, that is, the ratio dQ / dP of the heat collection increment ΔQ of the heat pump subsystem to the electric energy consumption increment ΔP is measured. Specifically, the heat collection increment ΔQ of the heat exchanger is calculated by measuring the flow rate of the circulating water pump 5 and the inlet and outlet water temperature difference, and dQ / dP is calculated with the corresponding electric energy consumption increment ΔP of the heat pump. When dQ / dP>0, the heat exchange rate of the heat pump is increased; when dQ / dP<0, the heat exchange rate of the heat pump is reduced.

[0080] Among them, in the above formula, d represents derivation, Q represents heat, and P represents energy consumption.

[0081] The collector outlet temperature and the thermal energy booster outlet temperature values ​​are obtained by setting optimization targets based on user needs and calculating through an optimization algorithm.

[0082] The series and parallel combination of the collector plates and the thermal energy enhancer in the collector subsystem is determined according to the set values ​​of the collector outlet temperature and the thermal energy enhancer outlet temperature.

[0083] The solar energy heat collection subsystem adjusts the speed of the circulating heat exchange according to the set temperature, that is, if the temperature of the thermal energy booster increases, the flow speed of the heat exchange medium is increased; otherwise, the flow speed of the heat exchange medium is reduced.

[0084] The heat exchange rate of the heat pump subsystem is controlled according to the heat increment rate. The heat increment rate is the ratio of the heat collection increment to the corresponding energy consumption increment. The heat increment rate of the heat pump is measured. When the heat increment rate of the heat pump subsystem is greater than zero, the heat exchange rate of the heat pump subsystem is increased; otherwise, the heat exchange rate of the heat pump subsystem is reduced.

[0085] In the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] In the description of the present invention, it is necessary to understand that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0087] In the description of this specification, the description of the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0088] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a high-efficiency solar thermal collection system based on heat pump technology, which is implemented using a high-efficiency solar thermal collection system based on heat pump technology. Its characteristics are: Includes two operating states: independent operation and joint operation; The independent operation refers to the operation of the solar thermal collector subsystem alone. First, the start and end time of the operation of the solar thermal collector subsystem is optimized, including: at noon when the sunlight is strong and the temperature is high, the time period with the highest heat is selected for heat collection; the joint operation refers to the joint operation of the heat pump and the thermal collector subsystem: the system operation time period is determined by the same method as the independent operation, and the outlet temperature value of the thermal energy enhancer is set according to user needs in combination with the ambient temperature, light intensity and the heat pump energy efficiency curve, and the speed and operation mode of the circulating heat exchange are adjusted according to the set temperature; when the amount of heat collected by the collector during the day does not meet the user's heat demand or the temperature of the hot water storage tank is quickly increased or when the ambient temperature is low, resulting in a low COP of the heat pump, the heat pump subsystem and the solar thermal collector subsystem are operated jointly; The method for selecting the start and end time comprises the following steps: Step 1. Calculate the user's heat demand; calculate the heat collected by the collector based on the ambient temperature, wind speed, and light intensity. The shortest time period for collecting heat to meet the user's heat demand is the start and end time of the solar heat collection subsystem operation; Step 2. Set the collector outlet temperature; Set the collector outlet temperature according to the minimum heat dissipation of the collector system; Step 3. According to the set collector outlet temperature, the series-parallel operation mode of the collector is changed by turning on and off the first, second and third electric-controlled valves, and the frequency conversion speed of the induced draft fan is controlled to change the heat exchange rate; when the first and third electric-controlled valves are turned on and the second electric-controlled valve is turned off, the collector is operated in series; when the first and second electric-controlled valves are turned on and the third electric-controlled valve is turned off, the collector is operated in parallel; The joint operation includes the following steps: Step (1) optimizing and selecting the start and end time of the operation of the solar energy collection subsystem; the optimization process is the same as the independent operation, that is, optimizing and selecting the start and end time of the operation of the solar energy collection subsystem according to the ambient temperature, wind speed and light intensity; Step (2) setting the collector outlet temperature; based on the ambient temperature, wind speed, light intensity, and with reference to the heat pump energy efficiency curve, the collector outlet temperature is set to a minimum energy consumption ratio of the collector system under the premise of meeting the user's thermal energy demand; the solar collector subsystem and the heat pump subsystem are controlled separately, and the solar collector subsystem controls the collector outlet temperature; if the collector outlet temperature rises, the wind speed of the induced draft fan is increased; otherwise, the wind speed of the induced draft fan is reduced; if the air temperature at the evaporator heat exchange outlet is lower than the ambient temperature, the heat exchanged air is directly discharged into the environment through the exhaust port, wherein the air heat exchange cycle is open-loop operation; if the air temperature at the evaporator heat exchange outlet is higher than the ambient temperature, the heat exchanged air is sent back to the collector through the temperature control switch, and the air heat exchange cycle is closed-loop operation; The heat pump subsystem control is based on the heat pump heat increment rate, that is, the ratio dQ / dP of the heat pump subsystem heat collection increment ΔQ and the electric energy consumption increment ΔP is measured. Specifically, the heat collection increment ΔQ of the heat exchanger is calculated by measuring the flow rate of the circulating water pump and the inlet and outlet water temperature difference, and dQ / dP is calculated with the corresponding heat pump electric energy consumption increment ΔP. When dQ / dP>0, the heat exchange rate of the heat pump is increased; when dQ / dP<0, the heat exchange rate of the heat pump is reduced. In the above formula, d represents the derivative, Q represents the heat, and P' represents the energy consumption. The collector outlet temperature and the thermal energy enhancer outlet temperature values ​​are optimization targets set according to user needs and calculated through an optimization algorithm; the series and parallel combination of the collector plates and the thermal energy enhancer in the collector subsystem is determined according to the set values ​​of the collector outlet temperature and the thermal energy enhancer outlet temperature; the solar collector subsystem adjusts the speed of the circulating heat exchange according to the set temperature, that is, if the temperature of the thermal energy enhancer increases, the flow speed of the heat exchange medium is increased; otherwise, the flow speed of the heat exchange medium is reduced; the heat exchange rate of the heat pump subsystem is controlled according to the heat increment rate, which is the ratio of the collector heat increment to the corresponding energy consumption increment; the heat increment rate of the heat pump is measured, and when the heat increment rate of the heat pump subsystem is greater than zero, the heat exchange rate of the heat pump subsystem is increased; otherwise, the heat exchange rate of the heat pump subsystem is reduced.

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