CN116007093B - Solar energy storage multi-source heat pump air conditioning system and heating method - Google Patents

Abstract

The invention discloses a solar energy storage multi-source heat pump air conditioning system and a heating method, wherein the solar energy storage multi-source heat pump air conditioning system comprises an air processing unit, a solar preheating heat storage unit, a phase change energy storage unit and a multi-source heat pump unit; the air treatment unit comprises a fresh air pipeline and an exhaust pipeline, and the fresh air pipeline is provided with an air heater; the air flow in the fresh air pipeline is heated for the second time through the air heater; the solar preheating heat storage unit is used for absorbing solar energy, converting the solar energy into heat energy and providing the heat energy for the air treatment unit and/or the phase change energy storage unit; the multi-source heat pump unit is used for providing the heat energy converted by the air heater to the air treatment unit; the phase-change energy storage unit comprises a phase-change heat storage tank, a first heat storage heat exchanger and a second heat storage heat exchanger, and is used for realizing energy transfer and energy storage between the solar preheating heat storage unit and the multi-source heat pump unit; the device has high system stability and obvious energy-saving and environment-friendly effects, and is a clean and efficient heating ventilation air conditioning system.

Description

A solar energy storage multi-source heat pump air conditioning system and heating method

Technical Field

The present invention belongs to the technical field of heat pumps, and in particular relates to a solar energy storage multi-source heat pump air conditioning system and a heating method.

Background technique

At present, the energy market is facing huge opportunities and challenges, and energy conservation and carbon reduction have become a hot topic of social concern. Traditional fossil energy can no longer meet the needs of sustainable development in today's society due to its non-renewable nature, low utilization efficiency, and serious environmental pollution. In this context, it is imperative to accelerate energy transformation, develop clean energy, promote the cascade utilization of energy systems, and improve energy utilization efficiency.

Compression heat pump technology is widely used due to its advantages such as high efficiency, flexible equipment installation, and continuous and stable operation. However, traditional air source compression heat pumps are driven by consuming high-grade electricity, have poor low-temperature performance, and are unable to utilize the peak-valley electricity price difference, resulting in high operating costs. They do not have the obvious advantage of energy saving and carbon reduction.

As the world's largest renewable clean energy, solar energy has good economy and environmental friendliness, but the light resources are affected by meteorological conditions and have disadvantages such as intermittency and instability. Phase change thermal storage materials are increasingly widely used in the energy field because of their advantages such as constant temperature, large heat storage density, small volume change, and good stability. Phase change materials absorb heat from the surrounding environment during their phase change process and release heat to the surrounding environment when needed to achieve the purpose of energy storage and control the temperature of the surrounding environment, which can solve the contradiction of energy supply and demand mismatch in time and space. However, the solar-air source heat pump system in the prior art mainly relies on electric energy to drive the heat pump for heating, resulting in high energy consumption of the compressor, and the utilization of solar energy is still very limited, and the cascade utilization of energy in the air-conditioning system cannot be achieved, resulting in energy waste and low energy utilization.

Summary of the invention

The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and to provide a solar energy storage multi-source heat pump air-conditioning system and a heating method. The device has high system stability and significant energy-saving and environmental protection effects. It is a clean and efficient HVAC system with broad application prospects.

To achieve the above-mentioned object, the present invention adopts the following technical scheme: a solar energy storage multi-source heat pump air conditioning system, comprising an air handling unit, a solar energy preheating heat storage unit, a phase change energy storage unit and a multi-source heat pump unit;

The air handling unit comprises a fresh air duct and an exhaust air duct, wherein the fresh air duct is provided with an air heater; the air flow in the fresh air duct is heated by the air heater;

The solar preheating heat storage unit is used to absorb solar energy and convert it into thermal energy, and provide the thermal energy to the air handling unit and/or the phase change energy storage unit;

The multi-source heat pump unit provides the converted heat energy to the air handling unit through the air heater;

The phase change energy storage unit includes a phase change heat storage tank, a first heat storage heat exchanger and a second heat storage heat exchanger, which are used to realize energy transfer and energy storage between the solar preheating heat storage unit and the multi-source heat pump unit; the first heat storage heat exchanger and the second heat storage heat exchanger are arranged in the phase change heat storage tank, wherein the inlet and outlet ends of the second heat storage heat exchanger are connected to the solar preheating heat storage unit, and the inlet and outlet ends of the first heat storage heat exchanger are connected to the multi-source heat pump unit.

As a preferred embodiment, it also includes a solar thermal storage unit; the solar preheating thermal storage unit includes a solar collector and a first circulating water pump, the water inlet of the solar collector is connected to the pipeline outlet of the second thermal storage heat exchanger through the first circulating water pump; a fresh air preheater is also provided on the fresh air duct, the fresh air preheater is located on the air inlet side of the air heater, and the fresh air preheater is used to preheat the fresh air entering the fresh air duct; the fresh air preheater includes a water channel and an air channel, the water outlet of the solar collector is connected to the water channel inlet of the fresh air preheater, the water channel outlet of the fresh air preheater is connected to the inlet of the second thermal storage heat exchanger, and both ends of the air duct of the fresh air preheater are connected to the fresh air duct.

As a preferred embodiment, the multi-element heat pump unit includes a first compressor and a condenser, the first compressor includes a low-pressure air inlet, a medium-pressure air inlet and a high-pressure exhaust port, the condenser includes a water channel and a refrigerant channel, the refrigerant channel inlet of the condenser is connected to the high-pressure exhaust port of the first compressor, and the refrigerant channel outlet of the condenser is connected to the inlet of the first heat storage heat exchanger, the air heater includes a water channel and an air channel, the water channel inlet and outlet of the air heater are connected to the water channel inlet and outlet of the condenser, and both ends of the air channel of the air heater are connected to the fresh air duct for heat exchange with the medium in the air channel in the air heater to heat the air medium in the fresh air duct.

As a preferred embodiment, the outlet of the first heat storage heat exchanger is connected to the inlet of the flash separator, and the flash separator also includes a return air port and a discharge port. The return air port of the flash separator is connected to the medium-pressure air inlet of the first compressor, and the discharge port of the flash separator is connected to the refrigerant inlet of the air source evaporator after throttling and reducing the pressure through the third throttling component. The refrigerant outlet of the air source evaporator is connected to the low-pressure air inlet of the first compressor.

As a preferred embodiment, the air inlet end of the pipeline of the medium-pressure air inlet of the first compressor is a U-shaped tube, and the U-shaped tube is located below the liquid level of the flash separator. The end of the U-shaped tube is provided with the return air port, and a plurality of oil return holes are formed on the surface of the tube body of the U-shaped tube. The oil return holes are used to allow the lubricating oil in the liquid medium of the flash separator to enter the first compressor along with the return air.

As a preferred solution, an exhaust heat recovery device is provided on the exhaust duct, and the exhaust heat recovery device is used to recover the waste heat of the exhaust duct. The exhaust heat recovery device includes an air channel and a refrigerant channel. The air channel of the exhaust heat recovery device is connected to the exhaust duct, and the refrigerant channel of the exhaust heat recovery device is connected to the multi-source heat pump unit.

As a preferred embodiment, the multi-source heat pump unit also includes a second compressor, which has a low-pressure air inlet and a high-pressure exhaust port. The high-pressure exhaust port of the second compressor is connected to the inlet of the refrigerant channel of the condenser, and the low-pressure air inlet of the second compressor is connected to the outlet of the refrigerant channel of the exhaust heat recovery device.

As a preferred embodiment, it also includes an economizer, which has a low-pressure channel and a high-pressure channel capable of performing heat exchange, the inlet of the high-pressure channel of the economizer is connected to the outlet of the refrigerant channel of the condenser, and the outlet of the high-pressure channel of the economizer is connected to the inlet of the refrigerant channel of the exhaust heat recovery device through a second throttling component; the inlet of the low-pressure channel of the economizer is connected to the outlet of the refrigerant channel of the condenser through a first throttling component, and the outlet of the low-pressure channel of the economizer is connected to the inlet of the refrigerant channel of the first heat storage heat exchanger.

The second object of the present invention is to provide a heating method for a solar energy storage multi-source heat pump air conditioning system, wherein the specific operating steps of the heating method are as follows: operating in four modes: heat storage mode, heat storage and heat release coupling mode, heat release mode, and neither heat storage nor heat release mode;

Phase change thermal storage tank works in thermal storage mode:

The temperature of the hot water output by the solar collector is higher than the ambient temperature. The solar preheating and heat storage unit provides the heat required for preheating the fresh air and the heat required for energy storage in the phase change heat storage tank to the fresh air preheater. The heat energy of the hot water output by the solar collector is first used to preheat the fresh air through the fresh air preheater, and then used to heat the phase change material of the phase change heat storage tank and store heat energy through the second heat storage heat exchanger, thereby realizing the cascade utilization of low-temperature hot water heat energy; the first throttling component is fully opened, and the refrigerant flows through the first throttling component but does not throttle and reduce the pressure. The refrigerant flows through the first heat storage heat exchanger without heat exchange, and the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator; at the same time, the multi-source heat pump unit absorbs waste heat from the air conditioning exhaust through the exhaust heat recovery device, and the hot water produced by the two parallel heat pump cycles provides heating to the air heater to process the air supply of the air conditioning, thereby realizing the cascade compression heat pump cycle heating process of the compressor at double evaporation temperature, thereby reducing the energy consumption of the compressor;

The phase change thermal storage tank works in a coupled mode of heat storage and heat release:

The temperature of hot water output by the solar thermal collector is higher than the ambient temperature. The heat energy of the hot water output by the solar thermal collector is first used to preheat the fresh air through the fresh air preheater, and then used to heat the phase change material of the phase change heat storage tank and store heat energy through the second heat storage heat exchanger, so as to realize the cascade utilization of low-temperature hot water heat energy; when the multi-source heat pump unit with the phase change heat storage tank and the exhaust heat recovery device as the low-temperature heat source cannot meet the heating demand of the air handling unit, the phase change heat storage tank, the exhaust heat recovery device and the air source evaporator form a three-temperature heat source, the first heat storage heat exchanger absorbs the energy stored in the phase change material, the exhaust heat recovery device absorbs the exhaust waste heat, and the air source evaporator absorbs the outdoor environment heat, and the refrigerant is throttled and reduced in pressure by the first throttling component, the second throttling component and the third throttling component to obtain a three-level evaporation pressure; the hot water of a certain temperature produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, so as to realize the cascade compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor;

Alternatively, when the phase-change heat storage tank and exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water of a certain temperature to fully meet the heating demand of the air handling unit, the phase-change heat storage tank and exhaust air form a dual-temperature heat source, the first heat storage heat exchanger absorbs the energy stored in the phase-change material, and the exhaust air heat recovery device absorbs the exhaust air waste heat, the third throttling component is completely closed, and the refrigerant is throttled and depressurized by the first throttling component and the second throttling component to obtain a two-stage evaporation pressure, and the hot water produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at the dual evaporation temperature, thereby reducing the energy consumption of the compressor;

The phase-change heat storage tank works in a heat release mode: when there is no solar energy, the phase-change heat storage tank provides the heat required for preheating the fresh air to the fresh air preheater and provides the required part of the heat supply to the air heater, and the second heat storage heat exchanger absorbs the heat released by the phase change material in the phase-change heat storage tank, which is used to preheat the fresh air through the fresh air preheater; when the phase-change heat storage tank and the exhaust heat recovery device as dual sources cannot meet the heating demand of the air handling unit, the phase-change heat storage tank, the exhaust heat recovery device and the air source evaporator form a three-temperature heat source, the first heat storage heat exchanger absorbs the heat released by the phase change material, the exhaust heat recovery device absorbs the exhaust waste heat, and the air source evaporator absorbs the outdoor environment heat, and the refrigerant is throttled and reduced in pressure by the first throttling component, the second throttling component and the third throttling component to obtain a three-level evaporation pressure; thus, the hot water of a certain temperature produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor;

Alternatively, when the phase change heat storage tank and exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water at a certain temperature to fully meet the heating demand of the air handling unit, the phase change heat storage tank and exhaust air form a dual-temperature heat source, the first heat storage heat exchanger absorbs the heat released by the phase change material and the exhaust air heat recovery device absorbs the exhaust air waste heat, the third throttling component is completely closed, and the refrigerant is throttled and reduced in pressure through the first throttling component and the second throttling component to obtain a two-stage evaporation pressure. The hot water of a certain temperature produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater to process the air conditioning supply, realizing the stepped compression heat pump cycle heating process of the compressor at dual evaporation temperatures, thereby reducing the energy consumption of the compressor.

The phase change heat storage tank works in a mode of neither storing nor releasing heat: the solar thermal storage unit stops working, and is unable to provide the fresh air preheater with the heat required for preheating the fresh air. The fresh air preheater does not work, and the multi-source heat pump unit only uses the exhaust heat recovery device and the air source evaporator to form a dual-temperature heat source to meet the heating required by the air handling unit; the first throttling component is fully open, and the refrigerant flows through the first throttling component but does not throttle and reduce the pressure. The refrigerant flows through the first heat storage heat exchanger without heat exchange, and the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator, so that hot water of a certain temperature produced by the parallel heat pump cycle with high and low compression ratios provides heating to the air heater to process the air conditioning supply, realizing the step-compression heat pump cycle heating process of the compressor at dual evaporation temperatures, thereby reducing the energy consumption of the compressor.

The present invention has at least the following beneficial effects:

First, through improvement, the multi-source heat pump air-conditioning system of the present invention consists of four major parts, namely, a solar water heating circulation unit, a phase change energy storage unit, a multi-source heat pump unit and an air handling unit. The solar water heating circulation unit can provide heat to the fresh air preheater on the one hand, and bear the fresh air preheating load, and on the other hand, it can also provide heat to the phase change heat storage tank to store the heat, thereby realizing the cascade utilization of low-temperature hot water thermal energy; the phase change energy storage unit realizes the energy transfer and energy storage between the solar water heating circulation units and the multi-source heat pump units. The phase change energy storage unit stores heat, and on the one hand, it can bear the fresh air preheating load, and on the other hand, it can also provide the heat at a higher temperature required for the low compression ratio compression heat pump circulation heating process; the exhaust heat recovery device is used to recover the waste heat of the exhaust air in the air handling unit, and the temperature grade can be improved through the multi-source heat pump unit. The air-conditioning system of the present invention has high stability and remarkable energy-saving and environmental protection effects.

Secondly, this scheme optimizes the heating process of the multi-source heat pump air conditioning system. According to the four operating modes of the phase change heat storage tank, namely, the heat storage mode, the heat storage and heat release coupling mode, the heat release mode and the mode of neither heat storage nor heat release, the organic coupling operation of the solar water heating circulation unit, the energy storage unit and the multi-source heat pump unit can be realized, and the heat storage and cascade preparation can be realized. Combined with the multi-source heat pump air conditioning system with a specific structure mentioned above, the multi-source heat pump unit can obtain heat from multiple low-temperature heat sources of different grades such as a double-temperature heat source or a three-temperature heat source according to different operating modes to bear the building heat load and part (or all) of the fresh air heat load, and realize the cascade compression heat pump cycle heating process of the compressor at multiple evaporation temperatures such as double evaporation temperatures or three evaporation temperatures, which can significantly reduce the energy consumption of the compressor, improve the heating efficiency of the compression heat pump cycle and the utilization rate of solar energy, and overcome the intermittent and low energy utilization rate of traditional solar heating.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a structural diagram of a multi-source heat pump air conditioning system of the present invention;

Markings in the figure: 1. first compressor, 2. condenser, 3. economizer, 4. flash separator, 5. air source evaporator, 6. second compressor, 7. exhaust heat recovery device, 8. phase change heat storage tank, 9. first heat storage heat exchanger, 10. second heat storage heat exchanger, 11. first circulating water pump, 12. solar collector, 13. fresh air preheater, 14. air heater, 15. second circulating water pump, 16. air conditioning system, 101. first throttling component, 102. second throttling component, 103. third throttling component, 201. first one-way valve, 202. second one-way valve, 301. fresh air duct, 302. exhaust air duct, 303. circulating duct.

Detailed ways

The present invention is described in detail below by means of exemplary embodiments. However, it should be understood that, without further description, elements, structures and features in one embodiment may also be beneficially combined in other embodiments.

It should be noted that: unless otherwise defined, the technical terms or scientific terms used in this document shall have the usual meanings understood by persons with ordinary skills in the field to which the invention belongs. The words "one", "an" or "the" and the like used in the patent application specification and claims of the present invention do not express quantitative limitations, but indicate the existence of at least one. Words such as "include" or "comprise" indicate that the elements or objects appearing before "include" or "comprises" include the elements or objects listed after "include" or "comprises" and their equivalents, but do not exclude other elements or objects with the same function.

As shown in the figure, this embodiment provides a solar energy storage multi-source heat pump air conditioning system, which consists of four parts: a solar water heating circulation unit, an energy storage unit, a multi-source heat pump unit and an air handling unit. Among them, the solar water heating circulation unit includes a solar collector 12, which is used to absorb solar energy and convert it into heat energy, and provide heat to the air handling unit through a fresh air preheater 13, and can provide heat to the phase change energy storage unit through a second heat storage heat exchanger 10 located in the phase change energy storage unit; the multi-source heat pump unit provides the converted heat energy to the air handling unit through an air heater 14, and can provide heat to the phase change energy storage unit through a first heat storage heat exchanger 9.

In this solution, the air handling unit includes a fresh air duct 301 and an exhaust air duct 302, and the fresh air duct 301 is provided with a fresh air preheater 13 and an air heater 14; the air heater 14 is arranged on the exhaust side of the air preheater 13, and the air preheated in the fresh air duct 301 is mixed with the exhaust air of the exhaust duct 302, and then enters the fresh air duct 301 for secondary heating by the air heater 14. The fresh air preheater 13 is used to preheat the fresh air. The fresh air preheater 13 includes a water channel and a fresh air channel, wherein both ends of the fresh air channel are connected to the fresh air duct 301. The air heater 14 is used to bear the building heat load and part (or all) of the fresh air heat load. The air heater 14 includes a refrigerant channel and an air channel. Both ends of the air channel of the air heater 14 are connected to the fresh air duct 301. Both ends of the refrigerant channel of the air heater 14 are connected to the multi-source heat pump unit. An exhaust heat recovery device 7 is provided on the exhaust duct 302. The exhaust heat recovery device 7 is used to recover the waste heat of the exhaust air of the air conditioning system, and the temperature is increased by the multi-source heat pump unit, and the exhaust heat recovery device 7 is used as part of the heating amount of the air heater 14 for heating the air conditioning supply air. The exhaust heat recovery device 7 includes an exhaust channel and a refrigerant channel. Both ends of the exhaust channel of the exhaust heat recovery device 7 are connected to the exhaust duct 302, and the refrigerant channel of the exhaust heat recovery device 7 is connected to the multi-source heat pump unit.

In this solution, the air handling unit further includes a circulation duct 303, the two ends of which are respectively connected to the fresh air duct 301 and the exhaust duct 302, and are used to introduce the exhaust air circulation of part of the exhaust duct 302 into the fresh air duct, thereby forming a mixed airflow with the fresh air. One end of the circulation duct 303 is connected to the fresh air duct 301 between the fresh air preheater 13 and the air heater 14. The other end of the circulation duct 303 is connected to the exhaust duct 302 on the air inlet side of the exhaust heat recovery device 7.

In this solution, the exhaust heat recovery device 7 is located on the exhaust duct 302. The exhaust heat recovery device 7 is used to absorb and recover the waste heat of the exhaust duct 302. The exhaust heat recovery device 7 includes an air channel and a refrigerant channel. The air channel of the exhaust heat recovery device 7 is connected to the exhaust duct 302, and the refrigerant channel of the exhaust heat recovery device 7 is connected to the multi-source heat pump unit.

In this solution, the inlet and outlet ends of the hot water channel of the air heater 14 are respectively connected to the outlet of the second circulating water pump 15 and the inlet of the hot water channel of the condenser 2, and the outlet of the hot water channel of the condenser 2 is connected to the inlet of the second circulating water pump 15, so that the condenser 2, the second circulating water pump 15 and the air heater 14 form a circulation loop.

In this scheme, the specific structure of the phase change energy storage unit is as follows: the phase change energy storage unit includes a phase change heat storage tank 8, a first heat storage heat exchanger 9 and a second heat storage heat exchanger 10. The phase change heat storage tank 8 is used to fill the phase change heat storage filler, which is a material with relatively stable performance such as fatty acid, polyol, paraffin, graphite or expanded graphite. Among them, the first heat storage heat exchanger 9 and the second heat storage heat exchanger 10 are arranged in the phase change heat storage tank 8 and submerged in the phase change heat storage filler. The first heat storage heat exchanger 9 and the second heat storage heat exchanger 10 are coil heat exchangers or fin tube heat exchangers. The inlet and outlet ends of the first heat storage heat exchanger 9 are respectively connected to the multi-source heat pump unit, and the inlet and outlet ends of the second heat storage heat exchanger 10 are respectively connected to the air handling unit and the solar water heating circulation unit. The energy storage unit is used for heat storage and (or) heat release.

In this solution, the solar preheating and heat storage unit is used to absorb solar energy and convert it into thermal energy. The solar preheating and heat storage unit can provide thermal energy to the air handling unit through the fresh air preheater 13; it can also store the converted thermal energy in the box-type energy storage unit through the second heat storage heat exchanger 10. The solar preheating and heat storage unit includes a solar collector 12 and a first circulating water pump 11. The water inlet of the solar collector 12 is connected to the outlet of the second heat storage heat exchanger 10 through the first circulating water pump 11, and the water outlet of the solar collector 12 is connected to the water channel inlet of the fresh air preheater 13, and the water channel outlet of the fresh air preheater 13 is connected to the inlet of the second heat storage heat exchanger 10.

In this scheme, the specific structure of the multi-source heat pump unit is as follows: the multi-source heat pump unit includes a first compressor 1, a second compressor 6, a condenser 2, an economizer 3, a flash separator 4, an air source evaporator 5, a first heat storage heat exchanger 9, and an exhaust heat recovery device 7, wherein the first compressor 1 has a low-pressure air intake port, a medium-pressure air intake port and a high-pressure air exhaust port, and the second compressor 6 has a low-pressure air intake port and a high-pressure air exhaust port; the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 are connected to the refrigerant channel inlet of the condenser 2, and the refrigerant channel outlet of the condenser 2 is divided into two branches, one of which is connected to the low-pressure side channel inlet of the economizer 3 through the first throttling component 101, and the low-pressure side channel outlet of the economizer 3 is connected to the inlet of the first heat storage heat exchanger 9, and the outlet of the first heat storage heat exchanger 9 is connected to the inlet of the flash separator 4, and the other branch of the refrigerant channel outlet of the condenser 2 is connected to the high-pressure side channel inlet of the economizer 3, and the high-pressure side channel outlet of the economizer 3 is connected to the exhaust heat recovery device 7 through the second throttling component 102. The refrigerant channel inlet of the recovery device 7 is connected, and the refrigerant channel outlet of the exhaust heat recovery device 7 is connected to the low-pressure air intake port of the second compressor 6; the return air port of the flash separator 4 is connected to the medium-pressure air intake port of the first compressor 1, and the bottom liquid outlet of the flash separator 4 is connected to the inlet of the air source evaporator 5 through the third throttling component 103, and the refrigerant outlet of the air source evaporator 5 is connected to the low-pressure air intake port of the first compressor 1; the first one-way valve 201 is set at the high-pressure exhaust port of the first compressor 1, and the second one-way valve 202 is set at the high-pressure exhaust port of the second compressor 6, and the outlets of the first one-way valve 201 and the second one-way valve 202 are connected to the refrigerant channel inlet of the condenser 2.

In this solution, the air inlet end of the pipeline of the medium-pressure air intake port of the first compressor 1 is a U-shaped tube, and the U-shaped tube is located below the liquid level inside the flash separator 4. The U-shaped tube has an air inlet, and a plurality of oil return holes are formed on the tube body of the U-shaped tube. The purpose of such design is: considering that lubricating oil may be accumulated at the bottom of the flash separator 4, and the lubricating oil flows with the refrigerant, by providing the oil return hole on the tube body of the U-shaped tube, the U-shaped tube is not only used for the gas above the flash separator 4 to return to the medium-pressure air intake port of the second compressor 1, but also the lubricating oil contained in the liquid phase part accumulated in the lower part of the flash separator 4 can be returned to the first compressor 1 through the oil return hole of the U-shaped tube, thereby avoiding the loss of lubricating oil. If there is no dual structure of the air intake port and the oil return hole of the U-shaped tube, this part of the lubricating oil cannot return to the compressor. The design value of this solution can avoid the problem of insufficient lubrication of the compressor caused by the loss of lubricating oil during operation.

This embodiment also provides a heating method for a solar energy storage multi-source heat pump air conditioning system, in which the phase change heat storage tank 8 operates in four modes: heat storage mode, heat storage and heat release coupling mode, heat release mode, and neither heat storage nor heat release mode. The specific operation modes are as follows:

First, the phase change heat storage tank 8 works in heat storage mode: the temperature of the hot water output by the solar thermal collector 12 is higher than the ambient temperature, the solar hot water circulation unit provides the fresh air preheater 13 with the heat required for preheating the fresh air and the heat required for energy storage in the phase change heat storage tank 8, the heat energy of the hot water output by the solar thermal collector 12 is first used to preheat the fresh air through the fresh air preheater 13, and then used to heat the phase change material of the phase change heat storage tank 8 and store energy through the second heat storage heat exchanger 10, thereby realizing the cascade utilization of low-temperature hot water heat energy; the first throttling component 101 is fully opened, the refrigerant flows through the first throttling component 101 but does not throttle and reduce the pressure, the refrigerant flows through the first heat storage heat exchanger 9 without heat exchange, the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator 5, and the heat is supplied by the first compressor 1, the first A one-way valve 201, a condenser 2, a first throttling component 101, an economizer 3, a first heat storage heat exchanger 9, a flash separator 4, a third throttling component 103 and an air source evaporator 5 form a heat pump cycle with an intermediate compression ratio to produce hot water above 50°C. At the same time, the multi-source heat pump unit absorbs waste heat from the air-conditioning exhaust through the exhaust heat recovery device 7. A second compressor 6, a second one-way valve 202, a condenser 2, a second throttling component 102 and an exhaust heat recovery device 7 form a heat pump cycle with a low compression ratio to produce hot water above 50°C. The hot water above 50°C produced by the two parallel heat pump cycles provides heating to the air heater 14 to process the air supply of the air conditioner, thereby realizing the step-compression heat pump cycle heating process of the compressor at double evaporation temperatures, thereby reducing the energy consumption of the compressor.

Secondly, the phase change heat storage tank 8 works in a heat storage and heat release coupling mode: the hot water temperature output by the solar thermal collector 12 is higher than the ambient temperature, and the heat energy of the hot water output by the solar thermal collector 12 is first used to preheat the fresh air through the fresh air preheater 13, and then used to heat the phase change material of the phase change heat storage tank 8 and store heat energy through the second heat storage heat exchanger 10, thereby realizing the cascade utilization of low-temperature hot water heat energy; when the phase change heat storage tank 8 and the exhaust air dual source as the heat pump unit of the low-temperature heat source produce hot water above 50°C and cannot meet the heating demand of the air handling unit, the phase change heat storage tank 8, the exhaust air and the outdoor environment form a three-temperature heat source, the first heat storage heat exchanger 9 absorbs the stored energy of the phase change material, and the exhaust air heat recovery device 7 absorbs the exhaust air waste heat and the air The air source evaporator 5 absorbs the heat of the outdoor environment, and the refrigerant is throttled and depressurized by the first throttling component 101, the second throttling component 102 and the third throttling component 103 to obtain a three-stage evaporation pressure. The heat pump cycle with an intermediate compression ratio composed of the second compressor 6, the second non-return valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust heat recovery device 7 produces hot water above 50°C. The double-source two-stage heat pump cycle with high compression ratio and low compression ratio composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5 produces hot water above 50°C, thereby Hot water above 50°C produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor; or, when the phase-change heat storage tank 8 and the exhaust air are used as the low-temperature dual-source heat pump unit to produce hot water above 50°C to fully meet the heating demand of the air handling unit, the phase-change heat storage tank 8 and the exhaust air form a dual-temperature heat source, the first heat storage heat exchanger 9 absorbs the stored energy of the phase change material and the exhaust heat recovery device 7 absorbs the exhaust waste heat, the third throttling component 103 is completely closed, and the refrigerant is throttled and reduced in pressure by the first throttling component 101 and the second throttling component 102 to obtain two The heat pump cycle with an intermediate compression ratio composed of the second compressor 6, the second non-return valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust heat recovery device 7 produces hot water above 50°C, and the single-stage heat pump cycle with a low compression ratio composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9 and the flash separator 4 produces hot water above 50°C, so that the hot water above 50°C produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater 14 to process the air conditioning supply, realizing the step-compression heat pump cycle heating process of the compressor at the double evaporation temperature, thereby reducing the energy consumption of the compressor.

Third, the phase change heat storage tank 8 works in a heat release mode: when there is no solar energy, such as at night, the phase change heat storage tank 8 of the solar hot water circulation unit provides the heat required for preheating the fresh air to the fresh air preheater 13 and provides the required part of the heat supply to the air heater 14, and the second heat storage heat exchanger 10 absorbs the heat released by the phase change material in the phase change heat storage tank, which is used to preheat the fresh air through the fresh air preheater 13; when the phase change heat storage tank 8 and the exhaust air dual source as the heat pump unit of the low-temperature heat source produce hot water above 50°C and cannot meet the heating demand of the air handling unit, the phase change heat storage tank 8, the exhaust air and the outdoor environment form a three-temperature heat source, the first heat storage heat exchanger 9 absorbs the heat released by the phase change material, the exhaust air heat recovery device 7 absorbs the exhaust air waste heat and The air source evaporator 5 absorbs heat from the outdoor environment, and the refrigerant is throttled and depressurized through the first throttling component 101, the second throttling component 102 and the third throttling component 103 to obtain a three-stage evaporation pressure. The heat pump cycle with an intermediate compression ratio composed of the second compressor 6, the second one-way valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust heat recovery device 7 produces hot water above 50°C. The dual-source two-stage heat pump cycle with high compression ratio and low compression ratio composed of the first compressor 1, the first one-way valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5 produces hot water above 50°C. The hot water above 50°C produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor; or, when the phase change heat storage tank 8 and the exhaust air are used as the low-temperature dual-source heat pump unit to produce hot water above 50°C to fully meet the heating demand of the air handling unit, the phase change heat storage tank 8 and the exhaust air form a dual-temperature heat source, the first heat storage heat exchanger 9 absorbs the heat released by the phase change material and the exhaust heat recovery device 7 absorbs the exhaust waste heat, the third throttling component 103 is completely closed, and the refrigerant is throttled and reduced in pressure by the first throttling component 101 and the second throttling component 102 to obtain two The heat pump cycle with an intermediate compression ratio composed of the second compressor 6, the second non-return valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust heat recovery device 7 produces hot water above 50°C, and the single-stage heat pump cycle with a low compression ratio composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9 and the flash separator 4 produces hot water above 50°C. Therefore, the hot water above 50°C produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at the double evaporation temperature, thereby reducing the energy consumption of the compressor.

Fourth, the phase-change heat storage tank 8 works in a mode of neither storing nor releasing heat: the solar water heating circulation unit stops working, and at this time, it is unable to provide the heat required for preheating the fresh air to the fresh air preheater 13, and the fresh air preheater 13 does not work. The multi-source heat pump unit produces hot water above 50°C and only uses the exhaust air and the outdoor environment to form a dual-temperature heat source to meet the heating required by the air handling unit; the first throttling component 101 is fully opened, and the refrigerant flows through the first throttling component but does not throttle and reduce the pressure. The refrigerant flows through the first heat storage heat exchanger 9 without heat exchange. The multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator 5, and is composed of the first compressor 1, the first check valve 201, the condenser 2, the first throttling component 101, and the economic The heat pump 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5 form a high compression ratio heat pump cycle to produce hot water above 50°C. At the same time, the multi-source heat pump unit absorbs waste heat from the air-conditioning exhaust through the exhaust heat recovery device 7, and the second compressor 6, the second one-way valve 202, the condenser 2, the second throttling component 102, and the exhaust heat recovery device 7 form a low compression ratio heat pump cycle to produce hot water above 50°C. The hot water above 50°C produced by the high and low compression ratio parallel heat pump cycles provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step compression heat pump cycle heating process of the compressor at double evaporation temperatures, thereby reducing the energy consumption of the compressor.

The scheme works as follows:

Operation mode 1: The phase change heat storage tank 8 works in heat storage mode. The hot water temperature output by the solar collector 12 is higher than the ambient temperature. The heat energy of the hot water output by the solar collector 12 is first used to preheat the fresh air through the fresh air preheater 13, and then used to heat the phase change material of the phase change heat storage tank 8 and store heat energy through the second heat storage heat exchanger 10, so as to realize the cascade utilization of low-temperature hot water heat energy; the first throttling component 101 is fully opened, the refrigerant flows through the first throttling component 101 but does not throttle and reduce pressure, and the refrigerant flows through the first heat storage heat exchanger 9 without heat exchange, and the multi-source heat pump unit receives the heat from the outdoor environment through the air source evaporator 5. The heat pump cycle with an intermediate compression ratio is composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5. At the same time, the multi-source heat pump unit absorbs waste heat from the air conditioning exhaust through the exhaust heat recovery device 7, and the heat pump cycle with a low compression ratio is composed of the second compressor 6, the second non-return valve 202, the condenser 2, the second throttling component 102, and the exhaust heat recovery device 7. The specific cycle process The high-temperature and high-pressure refrigerant vapor is respectively discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 and respectively passes through the first non-return valve 201 and the second non-return valve 202, and then flows into the refrigerant channel of the condenser 2 to be condensed into a high-temperature and high-pressure refrigerant liquid. The liquid outlet is divided into two branches. One branch flows into the economizer 3 after throttling and reducing the pressure through the first throttling component 101, and does not exchange heat with the first heat storage heat exchanger 9, and then flows into the flash separator 4 for gas-liquid separation. The flash separator 4 has a low temperature at the bottom. The medium-pressure refrigerant liquid passes through the liquid outlet, is throttled and depressurized by the third throttling component 103, and then flows into the air source evaporator 5, absorbs heat from the outdoor ambient air, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the first compressor 1; the other branch passes through the economizer 3 for heat exchange, and flows into the exhaust heat recovery device 7 after throttling and depressurization by the second throttling component 102, absorbs the waste heat of the air conditioning exhaust, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the second compressor 6, completing the two parallel heat pump cycle processes. Therefore, the hot water above 50°C produced by the two parallel heat pump cycles provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step compression heat pump cycle heating process of the compressor at the double evaporation temperature, thereby reducing the energy consumption of the compressor.

Operation mode 2: The phase change heat storage tank 8 works in a heat storage and heat release coupling mode. The hot water temperature output by the solar collector 12 is higher than the ambient temperature. The heat energy of the hot water output by the solar collector 12 is first used to preheat the fresh air through the fresh air preheater 13, and then used to heat the phase change material of the phase change heat storage tank 8 and store heat energy through the second heat storage heat exchanger 10; when the phase change heat storage tank 8 and the exhaust air dual source as the low-temperature heat source heat pump unit to produce hot water above 50°C cannot meet the heating demand of the air handling unit, the phase change heat storage tank 8, the exhaust air and the outdoor environment form a three-temperature heat source, which is composed of the second compressor 6, the second one-way valve 202, the condenser 2, and the economizer. 3, the second throttling component 102, and the exhaust heat recovery device 7 form a heat pump cycle with an intermediate compression ratio, and the double-source two-stage heat pump cycle with a high compression ratio and a low compression ratio is composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5. Specifically, the high-temperature and high-pressure refrigerant vapor is respectively discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 and respectively passes through the first non-return valve 201 and the second non-return valve 202. After being mixed and discharged to valve 202, the refrigerant channel flowing into condenser 2 is condensed into high-temperature and high-pressure refrigerant liquid. The liquid outlet is divided into two branches. One branch flows into economizer 3 after throttling and reducing pressure through the first throttling component 101, and then absorbs the heat released by the phase change material undergoing phase change through the first heat storage heat exchanger 9, evaporates into medium-temperature and medium-pressure refrigerant vapor, and then flows into flash separator 4 for gas-liquid separation. The medium-temperature and medium-pressure refrigerant saturated vapor at the upper part of flash separator 4 is sucked into the medium-pressure air intake port of the first compressor 1 through the gas outlet, and the bottom of flash separator 4 is sucked into the medium-pressure air intake port of the first compressor 1 through the gas outlet. The medium-temperature and medium-pressure refrigerant liquid passes through the liquid outlet, is throttled and depressurized by the third throttling component 103, and then flows into the air source evaporator 5, absorbs heat from the low-temperature ambient air, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the first compressor 1; the other branch passes through the economizer 3 for heat exchange, and flows into the exhaust heat recovery device 7 after throttling and depressurizing by the second throttling component 102, absorbs the exhaust heat of the air conditioner, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the second compressor 6, completing the three-source heat pump cycle process with high, medium and low compression ratios. Therefore, the hot water above 50°C produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor. Alternatively, when the phase-change heat storage tank 8 and the exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water above 50°C to fully meet the heating demand of the air handling unit, the phase-change heat storage tank 8 and the exhaust air form a dual-temperature heat source, and the second compressor 6, the second one-way valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust air heat recovery device 7 form a heat pump cycle with an intermediate compression ratio to produce hot water above 50°C, and the first compressor 1, the first one-way valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9 and the flash separator 4 form a single-stage heat pump cycle with a low compression ratio to produce hot water above 50°C. Specifically, high-temperature and high-pressure refrigerant vapor is respectively discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 and passes through the first one-way valve 201 and the second one-way valve 202 respectively. After the mixed gas is discharged through valve 202, the refrigerant channel flowing into the condenser 2 is condensed into a high-temperature and high-pressure refrigerant liquid, and the liquid outlet is divided into two branches. One branch flows into the economizer 3 after throttling and reducing the pressure through the first throttling component 101, and then absorbs the heat released by the phase change material undergoing phase change through the first heat storage heat exchanger 9, evaporates into medium-temperature and medium-pressure refrigerant vapor, and then flows into the flash separator 4, so that it is completely converted into medium-temperature and medium-pressure refrigerant saturated vapor, and is sucked into the medium-pressure air intake port of the first compressor 1 through the upper gas outlet of the flash separator 4; the other branch exchanges heat through the economizer 3, and flows into the exhaust heat recovery device 7 after throttling and reducing the pressure through the second throttling component 102, absorbs the exhaust waste heat of the air conditioner, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake port of the second compressor 6, completing the dual-source heat pump cycle process with medium and low compression ratios. Therefore, hot water above 50°C produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater 14 to process the air conditioning supply, realizing the step-compression heat pump cycle heating process of the compressor at double evaporation temperatures, thereby reducing the energy consumption of the compressor.

Operation mode three: The phase change heat storage tank 8 works in the heat release mode. When there is no solar energy, such as at night, the phase change heat storage tank 8 of the solar hot water circulation unit provides the heat required for preheating the fresh air to the fresh air preheater 13 and provides the required part of the heat supply to the air heater 14. The second heat storage heat exchanger 10 absorbs the heat released by the phase change material in the phase change heat storage tank, which is used to preheat the fresh air through the fresh air preheater 13; when the phase change heat storage tank 8 and the exhaust air dual source as the heat pump unit of the low-temperature heat source produce hot water above 50°C and cannot meet the heating demand of the air handling unit, the phase change heat storage tank 8, the exhaust air and the outdoor environment form a three-temperature heat source, which is composed of the second compressor 6, The second one-way valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust heat recovery device 7 form a heat pump cycle with an intermediate compression ratio, and the first compressor 1, the first one-way valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5 form a dual-source two-stage heat pump cycle with a high compression ratio and a low compression ratio, specifically: the high-temperature and high-pressure refrigerant vapor is respectively discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 and respectively passes through the first After the mixture is discharged from the first check valve 201 and the second check valve 202, the refrigerant channel flowing into the condenser 2 is condensed into a high-temperature and high-pressure refrigerant liquid. The liquid outlet is divided into two branches. One branch flows into the economizer 3 after throttling and reducing the pressure through the first throttling component 101, and then absorbs the heat released by the phase change material undergoing phase change through the first heat storage heat exchanger 9, evaporates into medium-temperature and medium-pressure refrigerant vapor, and then flows into the flash separator 4 for gas-liquid separation. The medium-temperature and medium-pressure refrigerant saturated vapor at the upper part of the flash separator 4 is sucked into the medium-pressure air intake port of the first compressor 1 through the gas outlet, and the flash separator 4 is sucked into the medium-pressure air intake port of the first compressor 1 through the gas outlet. The medium-temperature and medium-pressure refrigerant liquid at the bottom of the separator 4 passes through the liquid outlet, is throttled and depressurized by the third throttling component 103, and then flows into the air source evaporator 5, absorbs heat from the low-temperature ambient air, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the first compressor 1; the other branch passes through the economizer 3 for heat exchange, and flows into the exhaust heat recovery device 7 after throttling and depressurizing by the second throttling component 102, absorbs the waste heat of the air conditioning exhaust, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake of the second compressor 6, completing the high, medium and low compression ratio three-source heat pump cycle process. Therefore, the hot water above 50°C produced by the high, medium and low compression ratio three-source heat pump cycle provides heating to the air heater 14 to process the air supply of the air conditioner, realizing the step compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor. Alternatively, when the phase-change heat storage tank 8 and the exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water above 50°C to fully meet the heating demand of the air handling unit, the phase-change heat storage tank 8 and the exhaust air form a dual-temperature heat source, and the second compressor 6, the second one-way valve 202, the condenser 2, the economizer 3, the second throttling component 102, and the exhaust air heat recovery device 7 form a heat pump cycle with an intermediate compression ratio to produce hot water above 50°C, and the first compressor 1, the first one-way valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9 and the flash separator 4 form a single-stage heat pump cycle with a low compression ratio to produce hot water above 50°C. Specifically, high-temperature and high-pressure refrigerant vapor is respectively discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 and passes through the first one-way valve 201 and the second one-way valve 202 respectively. After the mixed gas is discharged through valve 202, the refrigerant channel flowing into the condenser 2 is condensed into a high-temperature and high-pressure refrigerant liquid, and the liquid outlet is divided into two branches. One branch flows into the economizer 3 after throttling and reducing the pressure through the first throttling component 101, and then absorbs the heat released by the phase change material undergoing phase change through the first heat storage heat exchanger 9, evaporates into medium-temperature and medium-pressure refrigerant vapor, and then flows into the flash separator 4, so that it is completely converted into medium-temperature and medium-pressure refrigerant saturated vapor, and is sucked into the medium-pressure air intake port of the first compressor 1 through the upper gas outlet of the flash separator 4; the other branch exchanges heat through the economizer 3, and flows into the exhaust heat recovery device 7 after throttling and reducing the pressure through the second throttling component 102, absorbs the exhaust waste heat of the air conditioner, evaporates into low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake port of the second compressor 6, completing the dual-source heat pump cycle process with medium and low compression ratios. Therefore, hot water above 50°C produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater 14 to process the air conditioning supply, realizing the step-compression heat pump cycle heating process of the compressor at double evaporation temperatures, thereby reducing the energy consumption of the compressor.

Operation mode 4: The phase-change heat storage tank 8 works in a mode that neither stores nor releases heat. The solar water heating circulation unit stops working, and is unable to provide the fresh air preheater 13 with the heat required to preheat the fresh air. The fresh air preheater 13 does not work, and the multi-source heat pump unit produces hot water above 50°C only through exhaust air and the outdoor environment to form a dual-temperature heat source to meet the heating required by the air handling unit; the first throttling component 101 is fully open, and the refrigerant flows through the first throttling component but does not throttle and reduce pressure. The refrigerant flows through the first heat storage heat exchanger 9 without heat exchange, and the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator 5. The heat pump cycle with a high compression ratio is composed of the first compressor 1, the first non-return valve 201, the condenser 2, the first throttling component 101, the economizer 3, the first heat storage heat exchanger 9, the flash separator 4, the third throttling component 103 and the air source evaporator 5. At the same time, the multi-source heat pump unit absorbs waste heat from the air conditioning exhaust through the exhaust heat recovery device 7, and the heat pump cycle with a low compression ratio is composed of the second compressor 6, the second non-return valve 202, the condenser 2, the second throttling component 102, and the exhaust heat recovery device 7. Specifically, the high temperature and high pressure After the refrigerant vapor is mixed and discharged from the high-pressure exhaust port of the first compressor 1 and the high-pressure exhaust port of the second compressor 6 respectively and passes through the first non-return valve 201 and the second non-return valve 202 respectively, it flows into the refrigerant channel of the condenser 2 and is condensed into a high-temperature and high-pressure refrigerant liquid. The liquid outlet is divided into two branches. One branch flows into the economizer 3 after throttling and reducing the pressure through the first throttling component 101, and does not exchange heat with the first heat storage heat exchanger 9, and then flows into the flash separator 4. The medium-temperature and medium-pressure refrigerant liquid at the bottom of the flash separator 4 passes through the liquid outlet and is throttled and reduced in pressure through the third throttling component 103, and then flows into the air source evaporator 5, absorbs heat from the outdoor ambient air, evaporates into a low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake port of the first compressor 1; the other branch exchanges heat through the economizer 3, and flows into the exhaust heat recovery device 7 after throttling and reducing the pressure through the second throttling component 102, absorbs the exhaust waste heat of the air conditioner, evaporates into a low-temperature and low-pressure refrigerant vapor, and is sucked into the low-pressure air intake port of the second compressor 6, completing the high and low compression ratio parallel heat pump cycle process. Therefore, hot water above 50°C produced by the parallel heat pump cycle with high and low compression ratios provides heating to the air heater 14 to process the air conditioning supply, realizing the step compression heat pump cycle heating process of the compressor at double evaporation temperatures, thereby reducing the energy consumption of the compressor.

The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims (4)

1. A solar energy storage multi-source heat pump air conditioning system, characterized by: comprising an air handling unit, a solar preheating and heat storage unit, a phase change energy storage unit and a multi-source heat pump unit; The air handling unit comprises a fresh air duct and an exhaust duct, wherein the fresh air duct is provided with an air heater; the air flow in the fresh air duct is heated by the air heater; a fresh air preheater is also provided on the fresh air duct, wherein the fresh air preheater is located at the air inlet side of the air heater, and the fresh air preheater is used to preheat the fresh air entering the fresh air duct; the fresh air preheater comprises a water channel and an air channel, the water outlet of the solar collector is connected to the water channel inlet of the fresh air preheater, the water channel outlet of the fresh air preheater is connected to the inlet of the second heat storage heat exchanger, and both ends of the air duct of the fresh air preheater are connected to the fresh air duct; The exhaust duct is provided with an exhaust heat recovery device, which is used to recover the waste heat of the exhaust duct. The exhaust heat recovery device includes an air channel and a refrigerant channel. The air channel of the exhaust heat recovery device is connected to the exhaust duct, and the refrigerant channel of the exhaust heat recovery device is connected to the multi-source heat pump unit. The solar preheating heat storage unit is used to absorb solar energy and convert it into thermal energy, and provide the thermal energy to the air handling unit and/or the phase change energy storage unit; The multi-source heat pump unit provides the converted heat energy to the air handling unit through the air heater; the multi-source heat pump unit includes a first compressor, a second compressor, a condenser and an economizer, the first compressor includes a low-pressure air inlet, a medium-pressure air inlet and a high-pressure exhaust port, the condenser includes a water channel and a refrigerant channel, the refrigerant channel inlet of the condenser is connected to the high-pressure exhaust port of the first compressor, the refrigerant channel outlet of the condenser is connected to the inlet of the first heat storage heat exchanger, the air heater includes a water channel and an air channel, the water channel inlet and outlet of the air heater are connected to the water channel inlet and outlet of the condenser, and both ends of the air channel of the air heater are connected to the fresh air duct for heat exchange with the medium in the air channel of the air heater to heat the air medium in the fresh air duct; The second compressor has a low-pressure air inlet and a high-pressure air outlet, the high-pressure air outlet of the second compressor is connected to the inlet of the refrigerant channel of the condenser, and the low-pressure air inlet of the second compressor is connected to the outlet of the refrigerant channel of the exhaust heat recovery device; The economizer has a low-pressure channel and a high-pressure channel capable of heat exchange, the high-pressure channel inlet of the economizer is connected to the refrigerant channel outlet of the condenser, and the high-pressure channel outlet of the economizer is connected to the refrigerant channel inlet of the exhaust heat recovery device through a second throttling component; the low-pressure channel inlet of the economizer is connected to the refrigerant channel outlet of the condenser through a first throttling component, and the low-pressure channel outlet of the economizer is connected to the refrigerant channel inlet of the first heat storage heat exchanger; The phase-change energy storage unit comprises a phase-change heat storage tank, a first heat storage heat exchanger and a second heat storage heat exchanger, which are used to realize energy transfer and energy storage between the solar preheating heat storage unit and the multi-source heat pump unit; the first heat storage heat exchanger and the second heat storage heat exchanger are arranged in the phase-change heat storage tank, wherein the inlet and outlet ends of the second heat storage heat exchanger are connected to the solar preheating heat storage unit, and the inlet and outlet ends of the first heat storage heat exchanger are connected to the multi-source heat pump unit; The outlet of the first heat storage heat exchanger is connected to the inlet of the flash separator, and the flash separator also includes a return air port and a discharge port. The return air port of the flash separator is connected to the medium-pressure air inlet of the first compressor, and the discharge port of the flash separator is connected to the refrigerant inlet of the air source evaporator after throttling and pressure reduction by the third throttling component. The refrigerant outlet of the air source evaporator is connected to the low-pressure air inlet of the first compressor. 2. A solar energy storage multi-source heat pump air conditioning system according to claim 1, characterized in that: the solar preheating heat storage unit includes a solar collector and a first circulating water pump, and the water inlet of the solar collector is connected to the pipeline outlet of the second heat storage heat exchanger through the first circulating water pump. 3. A solar energy storage multi-source heat pump air conditioning system according to claim 1, characterized in that: the air inlet end of the pipeline of the medium-pressure air inlet of the first compressor is a U-shaped tube, and the U-shaped tube is located below the liquid level of the flash separator, the end of the U-shaped tube is provided with the return air port, and a plurality of oil return holes are formed on the surface of the tube body of the U-shaped tube, and the oil return holes are used to allow the lubricating oil in the liquid medium of the flash separator to enter the first compressor along with the return air. 4. A heating method for a solar energy storage multi-source heat pump air conditioning system according to claim 1, characterized in that: the specific operating steps of the heating method are as follows: operating in four modes, namely, heat storage mode, heat storage and heat release coupling mode, heat release mode, and neither heat storage nor heat release mode; Phase change thermal storage tank works in thermal storage mode: The temperature of the hot water output by the solar collector is higher than the ambient temperature. The solar preheating and heat storage unit provides the heat required for preheating the fresh air and the heat required for energy storage in the phase change heat storage tank to the fresh air preheater. The heat energy of the hot water output by the solar collector is first used to preheat the fresh air through the fresh air preheater, and then used to heat the phase change material of the phase change heat storage tank and store heat energy through the second heat storage heat exchanger, thereby realizing the cascade utilization of low-temperature hot water heat energy; the first throttling component is fully opened, and the refrigerant flows through the first throttling component but does not throttle and reduce the pressure. The refrigerant flows through the first heat storage heat exchanger without heat exchange, and the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator; at the same time, the multi-source heat pump unit absorbs waste heat from the air conditioning exhaust through the exhaust heat recovery device, and the hot water produced by the two parallel heat pump cycles provides heating to the air heater to process the air supply of the air conditioning, thereby realizing the cascade compression heat pump cycle heating process of the compressor at double evaporation temperature, thereby reducing the energy consumption of the compressor; The phase change thermal storage tank works in a coupled mode of heat storage and heat release: The temperature of hot water output by the solar thermal collector is higher than the ambient temperature. The heat energy of the hot water output by the solar thermal collector is first used to preheat the fresh air through the fresh air preheater, and then used to heat the phase change material of the phase change heat storage tank and store heat energy through the second heat storage heat exchanger, so as to realize the cascade utilization of low-temperature hot water heat energy; when the multi-source heat pump unit with the phase change heat storage tank and the exhaust heat recovery device as the low-temperature heat source cannot meet the heating demand of the air handling unit, the phase change heat storage tank, the exhaust heat recovery device and the air source evaporator form a three-temperature heat source, the first heat storage heat exchanger absorbs the energy stored in the phase change material, the exhaust heat recovery device absorbs the exhaust waste heat, and the air source evaporator absorbs the outdoor environment heat, and the refrigerant is throttled and reduced in pressure by the first throttling component, the second throttling component and the third throttling component to obtain a three-level evaporation pressure; the hot water of a certain temperature produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, so as to realize the cascade compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor; Alternatively, when the phase-change heat storage tank and exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water of a certain temperature to fully meet the heating demand of the air handling unit, the phase-change heat storage tank and exhaust air form a dual-temperature heat source, the first heat storage heat exchanger absorbs the energy stored in the phase-change material, and the exhaust air heat recovery device absorbs the exhaust air waste heat, the third throttling component is completely closed, and the refrigerant is throttled and depressurized by the first throttling component and the second throttling component to obtain a two-stage evaporation pressure, and the hot water produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at the dual evaporation temperature, thereby reducing the energy consumption of the compressor; Phase change thermal storage tank works in heat release mode: When there is no solar energy, the phase change heat storage tank provides the heat required for preheating the fresh air to the fresh air preheater and provides the required part of the heat supply to the air heater. The second heat storage heat exchanger absorbs the heat released by the phase change material in the phase change heat storage tank, and uses it to preheat the fresh air through the fresh air preheater. When the dual sources of the phase change heat storage tank and the exhaust heat recovery device cannot meet the heating demand of the air handling unit, the phase change heat storage tank, the exhaust heat recovery device and the air source evaporator form a three-temperature heat source. The first heat storage heat exchanger absorbs the heat released by the phase change material, the exhaust heat recovery device absorbs the exhaust waste heat, and the air source evaporator absorbs the outdoor environment heat. The refrigerant is throttled and reduced in pressure by the first throttling component, the second throttling component and the third throttling component to obtain a three-level evaporation pressure. Therefore, the hot water of a certain temperature produced by the three-source heat pump cycle with high, medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at three evaporation temperatures, thereby reducing the energy consumption of the compressor. Alternatively, when the phase-change heat storage tank and the exhaust air are used as a low-temperature dual-source heat pump unit to produce hot water of a certain temperature to fully meet the heating demand of the air handling unit, the phase-change heat storage tank and the exhaust air form a dual-temperature heat source, the first heat storage heat exchanger absorbs the heat released by the phase-change material and the exhaust air heat recovery device absorbs the exhaust air waste heat, the third throttling component is completely closed, and the refrigerant is throttled and depressurized by the first throttling component and the second throttling component to obtain a two-stage evaporation pressure, and the hot water of a certain temperature produced by the dual-source heat pump cycle with medium and low compression ratios provides heating to the air heater to process the air supply of the air conditioner, realizing the step-compression heat pump cycle heating process of the compressor at the dual evaporation temperature, thereby reducing the energy consumption of the compressor; The phase change thermal storage tank works in a mode that neither stores nor releases heat: The solar thermal energy storage unit stops working and cannot provide the fresh air preheater with the heat required to preheat the fresh air. The fresh air preheater does not work, and the multi-source heat pump unit only uses the exhaust heat recovery device and the air source evaporator to form a dual-temperature heat source to meet the heating required by the air handling unit; the first throttling component is fully open, and the refrigerant flows through the first throttling component but does not throttle and reduce the pressure. The refrigerant flows through the first heat storage heat exchanger without heat exchange, and the multi-source heat pump unit absorbs heat from the outdoor environment through the air source evaporator, so that the hot water of a certain temperature produced by the parallel heat pump cycle with high and low compression ratios provides heating to the air heater to process the air conditioning supply, realizing the step-compression heat pump cycle heating process of the compressor at dual evaporation temperatures, thereby reducing the energy consumption of the compressor.