A composite energy system for drying and refrigerating agricultural products in a wide temperature range

Abstract

The present invention relates to a composite energy system for drying and cold-keeping agricultural products in a wide temperature range, belonging to the technical field of drying and cold-keeping agricultural products. The present invention comprises a heat pump system and a ventilation system. The heat pump system performs heat exchange between the refrigerant in the heat pump system and the return air in the ventilation system according to the requirements of cold-keeping or drying, thereby heating or cooling the return air in the ventilation system. The ventilation system is used to adjust the temperature, air supply volume and humidity of the return air in the ventilation system as needed according to the temperature and humidity requirements of cold-keeping or drying. The return air pre-cooling device in the ventilation system of the present invention uses outdoor fresh air as a natural cold source to reduce the temperature of the incoming return air, fully condense the refrigerant vapor, and improve the heating performance and operational stability of the heat pump. The present invention increases the temperature range provided by the heat pump to meet the needs of drying or cold-keeping. After the agricultural products that need to be dried are processed, the drying room can be converted into a cold storage room, thereby reducing investment and improving equipment utilization.

Description

Technical Field

[0001] The invention relates to a composite energy system for drying and refrigerating agricultural products in a wide temperature range, belonging to the technical field of drying and refrigerating agricultural products. Background Art

[0002] Heat pump drying is widely used in agricultural product processing and is employed throughout China. In some agricultural product production areas, both products require primary processing and drying, as well as refrigerated storage and preservation. Current equipment used for agricultural product drying or refrigeration and preservation suffers from limited functionality and low utilization rates. Furthermore, equipping a production area with both drying and refrigeration equipment not only results in high initial investment and a long payback period, but also high maintenance costs. By installing a wide-temperature-range agricultural product drying and refrigeration and preservation combined energy system, the drying room can be converted into a refrigerated storage room after the dried products are processed, reducing investment and increasing equipment utilization.

[0003] Current heat pump systems struggle to meet the heating requirements of both drying and refrigeration, and heat pump drying also has some drawbacks. During the drying process, if the return air temperature is too high, the refrigerant vapor in the condenser will not condense effectively, causing the heat pump system's heating performance to rapidly decline and system operation to become unstable. Furthermore, large amounts of high-temperature, high-humidity air are directly discharged into the atmosphere, resulting in significant waste of excess heat. Summary of the Invention

[0004] To address the problems and shortcomings of current equipment used for drying or refrigerating agricultural products, the present invention provides a wide-temperature-range agricultural product drying and refrigeration preservation composite energy system. This system allows the drying chamber to be converted into a refrigerated storage chamber after the agricultural products to be dried are processed, reducing investment and improving equipment utilization. The pre-cooling device uses outdoor fresh air as a natural cooling source to lower the return air temperature entering the return air heat exchanger, allowing the refrigerant vapor therein to fully condense, reducing throttling losses and increasing the heat release of the refrigerant in the return air heat exchanger, thereby improving the heating performance and operational stability of the heat pump. The dehumidified air flow waste heat recovery device uses outdoor fresh air to recover waste heat from the dehumidified air flow, reducing heat energy loss and lowering the energy consumption of the drying system.

[0005] The technical solution of the present invention is: a composite energy system for drying and refrigerating agricultural products in a wide temperature range, including a heat pump system and a ventilation system;

[0006] The heat pump system performs heat exchange between the refrigerant in the heat pump system and the return air in the ventilation system according to the requirements of refrigeration or drying. The wide pressure drop ratio two-way throttle valve 13 in the heat pump system increases the heating and cooling temperature range of the heat pump, thereby heating or cooling the return air in the ventilation system. The interface state of the four-way reversing valve 10 in the heat pump system is adjusted to realize the system in the drying condition or the refrigeration condition.

[0007] The ventilation system is used to adjust the temperature, air supply volume and humidity of the return air in the ventilation system as needed according to the temperature and humidity requirements of refrigeration, preservation or drying; the return air pre-cooling device 9 in the ventilation system uses outdoor fresh air as a natural cold source to reduce the return air temperature entering the return air heat exchanger 4, thereby reducing throttling losses, increasing the heat release of the refrigerant in the return air heat exchanger, and ultimately improving the heating performance and operational stability of the heat pump; the dehumidified air flow waste heat recovery device 15 in the ventilation system uses outdoor fresh air to recover the waste heat of the dehumidified air flow.

[0008] As a further solution of the present invention, the heat pump system includes: a return air heat exchanger 4, a four-way reversing valve 10, a compressor 11, a refrigerant pipeline 12, a wide pressure drop ratio bidirectional throttling device 13, and a fresh air heat exchanger 14;

[0009] The four-way reversing valve 10 includes four interfaces a, b, c, and d, and the interfaces a, b, c, and d of the four-way reversing valve 10 are respectively connected to a refrigerant pipeline;

[0010] The wide pressure drop ratio bidirectional throttling device 13 includes a heating throttle valve 1304, a heating check valve 1303, a cooling throttle valve 1301, and a cooling check valve 1302;

[0011] The exhaust port of the compressor 11 is connected to the a interface of the four-way reversing valve 10 through the refrigerant pipe 12, the b interface of the reversing valve 10 is connected to the refrigerant inlet of the return air heat exchanger 4 through the refrigerant pipe 12, the refrigerant outlet of the return air heat exchanger 4 is connected to the wide pressure drop ratio two-way throttling device 13 through the refrigerant pipe 12, the wide pressure drop ratio two-way throttling device 13 is connected to the refrigerant inlet of the fresh air heat exchanger 14 through the refrigerant pipe 12, the refrigerant outlet of the fresh air heat exchanger 14 is connected to the d interface of the four-way reversing valve 10 through the refrigerant pipe 12, and the c interface of the four-way reversing valve 10 is connected to the suction port of the compressor 11 through the refrigerant pipe 12.

[0012] As a further embodiment of the present invention, the ventilation system includes: a drying and refrigeration dual-purpose chamber 1, an air supply port 2, a circulating fan 3, a return air direct ventilation valve I 5, a return air duct 6, a return air port 7, a return air pre-cooling air valve 8, a return air pre-cooling device 9, a dehumidification air flow waste heat recovery device 15, a fresh air fan 16, a fresh air duct 17, a fresh air valve 18, a dehumidification air valve 19, a dehumidification fan 20, and a return air direct ventilation valve II 21;

[0013] The outlet of the drying and refrigerating dual-purpose chamber 1 is connected to the return air outlet 7, the return air outlet 7 is connected to the inlet of the return air direct ventilation valve II 21 through the return air duct 6, the outlet of the return air direct ventilation valve II 21 is connected to the inlet of the return air direct ventilation valve I5 through the return air duct 6, the outlet of the return air direct ventilation valve I5 is connected to the return air inlet of the return air heat exchanger 4 through the return air duct 6, the return air outlet of the return air heat exchanger 4 is connected to the circulation fan 3 through the return air duct 6, the circulation fan 3 is connected to the air supply outlet 2 through the return air duct 6, and the air supply outlet 2 is provided on the drying and refrigerating dual-purpose chamber 1;

[0014] The return air port 7 is connected to the inlet of the dehumidification fan 20 through the return air duct 6, the dehumidification fan 20 is connected to the dehumidification air valve 19 through the return air duct 6, the dehumidification air valve 19 is connected to the inlet of the dehumidification air flow waste heat recovery device 15 through the return air duct 6, the outlet of the dehumidification air flow waste heat recovery device 15 is connected to the fresh air valve 18 through the return air duct 6, and the fresh air valve 18 is finally connected to the inlet of the return air direct ventilation valve I 5 through the return air duct 6; the dehumidification air flow waste heat recovery device 15 recovers the waste heat of the dehumidification air flow with outdoor fresh air, thereby reducing heat energy loss and reducing energy consumption of the drying system;

[0015] The return air direct ventilation valve II 21 outlet is also connected to the return air pre-cooling valve 8 through the return air duct 6, the return air pre-cooling valve 8 is connected to the return air inlet of the return air pre-cooling device 9, and the return air outlet of the return air pre-cooling device 9 is connected to the return air inlet of the return air heat exchanger 4 through the return air duct 6;

[0016] The fresh air outlet of the return air pre-cooling device 9 is connected to the inlet of the fresh air fan 16 via a fresh air duct 17, and the fresh air fan 16 is connected to the fresh air inlet of the fresh air heat exchanger 14. The return air pre-cooling device 9 uses the outdoor fresh air as a natural cooling source to reduce the temperature of the return air entering the return air heat exchanger, fully condensing the refrigerant vapor therein, thereby improving the heating performance and operational stability of the heat pump.

[0017] As a further embodiment of the present invention, the wide-pressure-drop-ratio bidirectional throttling device 13 is used to increase the heat pump's temperature range, enabling the system to meet the required temperatures for drying or refrigeration. When the system is operating in the drying mode, the refrigerant sequentially passes through the heating check valve 1303 and the heating throttle valve 1304 in the wide-pressure-drop-ratio bidirectional throttling device 13. When the system is operating in the refrigeration mode, the refrigerant sequentially passes through the cooling check valve 1302 and the cooling throttle valve 1301 in the wide-pressure-drop-ratio bidirectional throttling device 13. The type and model of the heating throttle valve 1304 are selected based on the required drying temperature range, while the type and model of the cooling throttle valve 1301 are selected based on the required refrigeration temperature range. This ensures that the temperature range of the agricultural product drying and refrigeration preservation composite energy system is met over a wide temperature range.

[0018] As a further embodiment of the present invention, during the drying operation, the high-temperature, high-pressure refrigerant passes through the refrigerant pipe 12, sequentially through the exhaust port of the compressor 11, the port a of the four-way reversing valve 10, and the port b of the four-way reversing valve 10, and enters the refrigerant inlet of the return air heat exchanger 4. The high-temperature, high-pressure refrigerant vapor enters the return air heat exchanger 4 and exchanges heat with the return air simultaneously entering the return air heat exchanger 4 from the return air pipe 6. The refrigerant temperature decreases and condenses into liquid refrigerant, and the return air temperature increases.

[0019] The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger 4, the heating one-way valve 1303, the heating throttle valve 1304, and the refrigerant inlet of the fresh air heat exchanger 14 through the refrigerant pipe 12 in sequence; the liquid refrigerant enters the fresh air heat exchanger 14 and exchanges heat with the fresh air entering the fresh air heat exchanger 14 from the fresh air pipe 17 at the same time. The refrigerant temperature rises to refrigerant vapor, and the fresh air temperature rises; the fresh air after heat exchange is discharged into the air;

[0020] The refrigerant vapor passes through the fresh air heat exchanger 14, the d interface of the four-way reversing valve 10, and the c interface of the four-way reversing valve 10 in sequence, enters the compressor 11 for compression, and generates high-temperature and high-pressure refrigerant vapor which is discharged from the exhaust port of the compressor 11.

[0021] As a further solution of the present invention, in the drying condition, when the return air temperature is low and dehumidification is not required, the return air pre-cooling air valve 8, the fresh air air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve I5 and the return air direct ventilation valve II 21 are opened;

[0022] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21 and the return air direct ventilation valve I 5 through the return air duct 6 to enter the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature increases, and the heated return air passes through the return air duct 6 and enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulation fan 3 to dry the materials.

[0023] As a further solution of the present invention, when the return air temperature reaches a certain set value during drying, the return air direct ventilation valve I5, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve II21, the return air pre-cooling air valve 8, and the fresh air fan 16 are opened;

[0024] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21, the return air pre-cooling valve 8, and enters the return air pre-cooling device 9 through the return air duct 6 to exchange heat with the fresh air. The cooled return air enters the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor to reduce the return air temperature entering the return air heat exchanger, so that the refrigerant therein is fully condensed to improve the heating performance and operational stability of the heat pump. At the same time, the outdoor fresh air after heat exchange is sent to the fresh air heat exchanger to exchange heat with the refrigerant to increase the evaporation temperature of the refrigerant; the return air temperature rises, and the heated return air enters the drying and refrigerating chamber 1 through the air supply port 2 under the traction of the circulation fan 3, and the fresh air is sent to the fresh air heat exchanger 14 under the traction of the fresh air fan 16.

[0025] As a further solution of the present invention, when dehumidification is required under dry working conditions, the return air pre-cooling air valve 8 and the return air direct ventilation valve II 21 are closed, and the return air direct ventilation valve I 5, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are opened;

[0026] The return air in the drying and refrigeration chamber 1 flows out from the return air port 7, and then passes through the return air duct 6 and the dehumidification air valve 19 under the traction of the dehumidification fan 20 to enter the dehumidification air flow waste heat recovery device 15 for heat exchange with the outdoor fresh air. The return air after heat exchange is discharged to the atmosphere, and the outdoor fresh air after heat exchange is sent to the return air heat exchanger for further heating to recover part of the dehumidification waste heat and reduce the drying energy consumption; the fresh air passes through the return air duct 6, passes through the fresh air valve 18 and the return air direct ventilation valve Ⅰ5, and enters the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature rises, and the heated return air enters the drying and refrigeration chamber 1 through the air supply port 2 under the traction of the circulation fan 3 to achieve the purpose of drying the materials and dehumidifying the return air.

[0027] As a further embodiment of the present invention, during refrigeration operation, high-temperature, high-pressure refrigerant passes through the refrigerant pipe 12, sequentially through the exhaust port of the compressor 11, the port a of the four-way reversing valve 10, and the port d of the four-way reversing valve 10, and enters the refrigerant inlet of the fresh air heat exchanger 14. The high-temperature, high-pressure refrigerant vapor enters the fresh air heat exchanger 14 and exchanges heat with the fresh air simultaneously entering the fresh air heat exchanger 14 from the fresh air pipe 17. The refrigerant temperature decreases and condenses into liquid refrigerant, while the fresh air temperature increases. The fresh air after heat exchange is discharged into the air.

[0028] The liquid refrigerant passes through the refrigerant outlet of the fresh air heat exchanger 14, the refrigeration check valve 1302, the refrigeration throttle valve 1301, and the refrigerant inlet of the return air heat exchanger 4 through the refrigerant pipe 12 in sequence; the liquid refrigerant enters the return air heat exchanger 4 and exchanges heat with the return air entering the return air heat exchanger 4 from the return air pipe 6 at the same time. The refrigerant temperature increases to refrigerant vapor, and the return air temperature decreases.

[0029] The refrigerant vapor passes through the outlet of the return air heat exchanger 4, the b interface of the four-way reversing valve 10, and the c interface of the four-way reversing valve 10 in sequence, enters the compressor 11 for compression, and generates high-temperature and high-pressure refrigerant vapor and is discharged from the exhaust port of the compressor 11.

[0030] As a further solution of the present invention, in the refrigeration working condition, the return air pre-cooling air valve 8, the fresh air air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve I5 and the return air direct ventilation valve II 21 are opened;

[0031] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21 and the return air direct ventilation valve I 5 through the return air duct 6 to enter the return air heat exchanger 4 to exchange heat with the liquid refrigerant. The return air temperature is reduced. The cooled return air enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulation fan 3 to refrigerate the materials.

[0032] The beneficial effects of the present invention are:

[0033] 1. Use a wide pressure drop ratio two-way throttling device to increase the temperature range that the heat pump system can provide to meet the needs of drying or refrigeration;

[0034] 2. Set up a return air pre-cooling device to reduce the return air temperature entering the return air heat exchanger under dry conditions, so that the refrigerant in the return air heat exchanger is fully condensed, which can effectively improve the heating performance and operation stability of the heat pump;

[0035] 3. Install a dehumidified airflow waste heat recovery device to recover the waste heat of the dehumidified airflow under drying conditions, reduce heat energy loss and thus reduce the energy consumption of the drying system;

[0036] 4. After the agricultural products that need to be dried are processed, the drying room can be converted into a cold storage room, reducing investment and improving equipment utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the composition of the present invention;

[0038] Figure 2 It is a structural diagram of a wide pressure drop ratio bidirectional throttling device.

[0039] Figure 1The reference numbers indicate in sequence: 1-drying and refrigeration chamber, 2-air supply outlet, 3-circulating fan, 4-return air heat exchanger, 5-return air direct ventilation valve I, 6-return air duct, 7-return air outlet, 8-return air pre-cooling valve, 9-return air pre-cooling device, 10-four-way reversing valve, 11-compressor, 12-refrigerant pipeline, 13-wide pressure drop ratio two-way throttling device, 14-fresh air heat exchanger, 15-exhaust heat recovery device, 16-fresh air fan, 17-fresh air duct, 18-fresh air valve, 19-exhaust air valve, 20-exhaust fan, 21-return air direct ventilation valve II;

[0040] Figure 2 The reference numerals represent in sequence: 1301 - cooling throttle valve, 1302 - cooling one-way valve, 1303 - heating one-way valve, 1304 - heating throttle valve. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] Example 1: Figure 1 As shown, a composite energy system for drying and refrigerating agricultural products in a wide temperature range includes a heat pump system and a ventilation system;

[0043] The heat pump system performs heat exchange between the refrigerant in the heat pump system and the return air in the ventilation system according to the requirements of refrigeration or drying. The wide pressure drop ratio two-way throttle valve 13 in the heat pump system increases the heating and cooling temperature range of the heat pump, thereby heating or cooling the return air in the ventilation system. The interface state of the four-way reversing valve 10 in the heat pump system is adjusted to realize the system in the drying condition or the refrigeration condition.

[0044] The ventilation system is used to adjust the temperature, air supply volume and humidity of the return air in the ventilation system as needed according to the temperature and humidity requirements of refrigeration, preservation or drying; the return air pre-cooling device 9 in the ventilation system uses outdoor fresh air as a natural cold source to reduce the return air temperature entering the return air heat exchanger 4, thereby reducing throttling losses, increasing the heat release of the refrigerant in the return air heat exchanger, and ultimately improving the heating performance and operational stability of the heat pump; the dehumidified air flow waste heat recovery device 15 in the ventilation system uses outdoor fresh air to recover the waste heat of the dehumidified air flow.

[0045] As a further solution of the present invention, the heat pump system includes: a return air heat exchanger 4, a four-way reversing valve 10, a compressor 11, a refrigerant pipeline 12, a wide pressure drop ratio bidirectional throttling device 13, and a fresh air heat exchanger 14;

[0046] The four-way reversing valve 10 includes four interfaces a, b, c, and d, and the interfaces a, b, c, and d of the four-way reversing valve 10 are respectively connected to a refrigerant pipeline;

[0047] The wide pressure drop ratio bidirectional throttling device 13 includes a heating throttle valve 1304, a heating check valve 1303, a cooling throttle valve 1301, and a cooling check valve 1302;

[0048] The exhaust port of the compressor 11 is connected to the a interface of the four-way reversing valve 10 through the refrigerant pipe 12, the b interface of the reversing valve 10 is connected to the refrigerant inlet of the return air heat exchanger 4 through the refrigerant pipe 12, the refrigerant outlet of the return air heat exchanger 4 is connected to the wide pressure drop ratio two-way throttling device 13 through the refrigerant pipe 12, the wide pressure drop ratio two-way throttling device 13 is connected to the refrigerant inlet of the fresh air heat exchanger 14 through the refrigerant pipe 12, the refrigerant outlet of the fresh air heat exchanger 14 is connected to the d interface of the four-way reversing valve 10 through the refrigerant pipe 12, and the c interface of the four-way reversing valve 10 is connected to the suction port of the compressor 11 through the refrigerant pipe 12.

[0049] As a further embodiment of the present invention, the ventilation system includes: a drying and refrigeration dual-purpose chamber 1, an air supply port 2, a circulating fan 3, a return air direct ventilation valve I 5, a return air duct 6, a return air port 7, a return air pre-cooling air valve 8, a return air pre-cooling device 9, a dehumidification air flow waste heat recovery device 15, a fresh air fan 16, a fresh air duct 17, a fresh air valve 18, a dehumidification air valve 19, a dehumidification fan 20, and a return air direct ventilation valve II 21;

[0050] The outlet of the drying and refrigerating dual-purpose chamber 1 is connected to the return air outlet 7, the return air outlet 7 is connected to the inlet of the return air direct ventilation valve II 21 through the return air duct 6, the outlet of the return air direct ventilation valve II 21 is connected to the inlet of the return air direct ventilation valve I5 through the return air duct 6, the outlet of the return air direct ventilation valve I5 is connected to the return air inlet of the return air heat exchanger 4 through the return air duct 6, the return air outlet of the return air heat exchanger 4 is connected to the circulation fan 3 through the return air duct 6, the circulation fan 3 is connected to the air supply outlet 2 through the return air duct 6, and the air supply outlet 2 is provided on the drying and refrigerating dual-purpose chamber 1;

[0051] The return air port 7 is connected to the inlet of the dehumidification fan 20 through the return air duct 6, the dehumidification fan 20 is connected to the dehumidification air valve 19 through the return air duct 6, the dehumidification air valve 19 is connected to the inlet of the dehumidification air flow waste heat recovery device 15 through the return air duct 6, the outlet of the dehumidification air flow waste heat recovery device 15 is connected to the fresh air valve 18 through the return air duct 6, and the fresh air valve 18 is finally connected to the inlet of the return air direct ventilation valve I 5 through the return air duct 6; the dehumidification air flow waste heat recovery device 15 recovers the waste heat of the dehumidification air flow with outdoor fresh air, thereby reducing heat energy loss and reducing energy consumption of the drying system;

[0052] The return air direct ventilation valve II 21 outlet is also connected to the return air pre-cooling valve 8 through the return air duct 6, the return air pre-cooling valve 8 is connected to the return air inlet of the return air pre-cooling device 9, and the return air outlet of the return air pre-cooling device 9 is connected to the return air inlet of the return air heat exchanger 4 through the return air duct 6;

[0053] The fresh air outlet of the return air pre-cooling device 9 is connected to the inlet of the fresh air fan 16 via a fresh air duct 17, and the fresh air fan 16 is connected to the fresh air inlet of the fresh air heat exchanger 14. The return air pre-cooling device 9 uses the outdoor fresh air as a natural cooling source to reduce the temperature of the return air entering the return air heat exchanger, fully condensing the refrigerant vapor therein, thereby improving the heating performance and operational stability of the heat pump.

[0054] As a further solution of the present invention, the wide pressure drop ratio two-way throttling device 13 is used to improve the temperature supply range of the heat pump so that the system can meet the temperature required for drying or refrigeration and preservation; when the system is in a drying condition, the refrigerant passes through the heating one-way valve 1303 and the heating throttle valve 1304 in the wide pressure drop ratio two-way throttling device 13 in sequence; when the system is in a refrigeration and preservation condition, the refrigerant passes through the refrigeration one-way valve 1302 and the refrigeration throttle valve 1301 in the wide pressure drop ratio two-way throttling device 13 in sequence.

[0055] As a further embodiment of the present invention, during the drying operation, the high-temperature, high-pressure refrigerant passes through the refrigerant pipe 12, sequentially through the exhaust port of the compressor 11, the port a of the four-way reversing valve 10, and the port b of the four-way reversing valve 10, and enters the refrigerant inlet of the return air heat exchanger 4. The high-temperature, high-pressure refrigerant vapor enters the return air heat exchanger 4 and exchanges heat with the return air simultaneously entering the return air heat exchanger 4 from the return air pipe 6. The refrigerant temperature decreases and condenses into liquid refrigerant, and the return air temperature increases.

[0056] The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger 4, the heating one-way valve 1303, the heating throttle valve 1304, and the refrigerant inlet of the fresh air heat exchanger 14 through the refrigerant pipe 12 in sequence; the liquid refrigerant enters the fresh air heat exchanger 14 and exchanges heat with the fresh air entering the fresh air heat exchanger 14 from the fresh air pipe 17 at the same time. The refrigerant temperature rises to refrigerant vapor, and the fresh air temperature rises; the fresh air after heat exchange is discharged into the air;

[0057] The refrigerant vapor passes through the fresh air heat exchanger 14, the d interface of the four-way reversing valve 10, and the c interface of the four-way reversing valve 10 in sequence, enters the compressor 11 for compression, and generates high-temperature and high-pressure refrigerant vapor which is discharged from the exhaust port of the compressor 11.

[0058] As a further solution of the present invention, in the drying condition, when the return air temperature is low and dehumidification is not required, the return air pre-cooling air valve 8, the fresh air air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve I5 and the return air direct ventilation valve II 21 are opened;

[0059] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21 and the return air direct ventilation valve I 5 through the return air duct 6 to enter the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature increases, and the heated return air passes through the return air duct 6 and enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulation fan 3 to dry the materials.

[0060] As a further solution of the present invention, when the return air temperature reaches a certain set value during drying, the return air direct ventilation valve I5, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve II21, the return air pre-cooling air valve 8, and the fresh air fan 16 are opened;

[0061] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21, the return air pre-cooling valve 8, and enters the return air pre-cooling device 9 through the return air duct 6 to exchange heat with the fresh air. The cooled return air enters the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor to reduce the return air temperature entering the return air heat exchanger, so that the refrigerant therein is fully condensed to improve the heating performance and operational stability of the heat pump. At the same time, the outdoor fresh air after heat exchange is sent to the fresh air heat exchanger to exchange heat with the refrigerant to increase the evaporation temperature of the refrigerant; the return air temperature rises, and the heated return air enters the drying and refrigerating chamber 1 through the air supply port 2 under the traction of the circulation fan 3, and the fresh air is sent to the fresh air heat exchanger 14 under the traction of the fresh air fan 16.

[0062] As a further solution of the present invention, when dehumidification is required under dry working conditions, the return air pre-cooling air valve 8 and the return air direct ventilation valve II 21 are closed, and the return air direct ventilation valve I 5, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are opened;

[0063] The return air in the drying and refrigeration chamber 1 flows out from the return air port 7, and then passes through the return air duct 6 and the dehumidification air valve 19 under the traction of the dehumidification fan 20 to enter the dehumidification air flow waste heat recovery device 15 for heat exchange with the outdoor fresh air. The return air after heat exchange is discharged to the atmosphere, and the outdoor fresh air after heat exchange is sent to the return air heat exchanger for further heating to recover part of the dehumidification waste heat and reduce the drying energy consumption; the fresh air passes through the return air duct 6, passes through the fresh air valve 18 and the return air direct ventilation valve Ⅰ5, and enters the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature rises, and the heated return air enters the drying and refrigeration chamber 1 through the air supply port 2 under the traction of the circulation fan 3 to achieve the purpose of drying the materials and dehumidifying the return air.

[0064] As a further embodiment of the present invention, during refrigeration operation, high-temperature, high-pressure refrigerant passes through the refrigerant pipe 12, sequentially through the exhaust port of the compressor 11, the port a of the four-way reversing valve 10, and the port d of the four-way reversing valve 10, and enters the refrigerant inlet of the fresh air heat exchanger 14. The high-temperature, high-pressure refrigerant vapor enters the fresh air heat exchanger 14 and exchanges heat with the fresh air simultaneously entering the fresh air heat exchanger 14 from the fresh air pipe 17. The refrigerant temperature decreases and condenses into liquid refrigerant, while the fresh air temperature increases. The fresh air after heat exchange is discharged into the air.

[0065] The liquid refrigerant passes through the refrigerant outlet of the fresh air heat exchanger 14, the refrigeration check valve 1302, the refrigeration throttle valve 1301, and the refrigerant inlet of the return air heat exchanger 4 through the refrigerant pipe 12 in sequence; the liquid refrigerant enters the return air heat exchanger 4 and exchanges heat with the return air entering the return air heat exchanger 4 from the return air pipe 6 at the same time. The refrigerant temperature increases to refrigerant vapor, and the return air temperature decreases.

[0066] The refrigerant vapor passes through the outlet of the return air heat exchanger 4, the b interface of the four-way reversing valve 10, and the c interface of the four-way reversing valve 10 in sequence, enters the compressor 11 for compression, and generates high-temperature and high-pressure refrigerant vapor and is discharged from the exhaust port of the compressor 11.

[0067] As a further solution of the present invention, in the refrigeration working condition, the return air pre-cooling air valve 8, the fresh air air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve I5 and the return air direct ventilation valve II 21 are opened;

[0068] The return air in the drying and refrigerating chamber 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve II 21 and the return air direct ventilation valve I 5 through the return air duct 6 to enter the return air heat exchanger 4 to exchange heat with the liquid refrigerant. The return air temperature is reduced. The cooled return air enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulation fan 3 to refrigerate the materials.

[0069] In the drying mode, the system's exhaust port is connected to port a of the four-way reversing valve 10 via a refrigerant pipe 12. Port b of the four-way reversing valve 10 is connected to the inlet of the return air heat exchanger 4 via a refrigerant pipe 12. High-temperature, high-pressure refrigerant vapor, compressed by compressor 11, enters the return air heat exchanger 4, where it undergoes heat exchange with the return air from the return air duct 6. The refrigerant's temperature decreases and condenses into liquid refrigerant. The return air, then warms up, enters the drying and refrigeration chamber 1 through the air supply port 2. The outlet of the return air heat exchanger 4 is connected to the inlet of a wide-pressure-drop ratio two-way throttling device 13 via a refrigerant pipe 12. The refrigerant then passes through the heating check valve 1303 and the heating throttle valve 1304. The outlet of the wide-pressure-drop ratio two-way throttling device 13 is connected to the inlet of the fresh air heat exchanger 14 via a refrigerant pipe. The liquid refrigerant exchanges heat with the outdoor fresh air in the fresh air heat exchanger 14, absorbing heat and evaporating into refrigerant vapor. The refrigerant vapor discharged from the fresh air heat exchanger 14 enters the four-way reversing valve 10 through the refrigerant pipe 12 at the port d of the four-way reversing valve 10, and is then discharged from the port c of the four-way reversing valve 10. The refrigerant vapor discharged from the port c of the four-way reversing valve 10 enters the compressor 11 from the intake port, is compressed again, and is discharged from the exhaust port of the compressor 11.

[0070] According to the requirements of the drying process for the temperature and relative humidity in the drying room during the drying process, the states of the return air direct ventilation valve 5, the return air pre-cooling air valve 8, the fresh air fan 16, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are adjusted as needed. When the return air temperature is low and dehumidification is not required, the return air pre-cooling air valve 8, the fresh air fan 16, the fresh air valve 18, the dehumidification air valve 19, and the dehumidification fan 20 are closed, and the return air direct ventilation valve 5 is opened. The return air from the drying and refrigerating dual-purpose room 1 flows out from the return air port 7, and then flows through the return air direct ventilation valve 5 through the return air duct 6 to enter the return air heat exchanger 4 for heating. The heated return air enters the drying and refrigerating dual-purpose room 1 from the air supply port 2 under the traction of the circulation fan 3; when dehumidification is required, the return air pre-cooling air valve 8 and the fresh air fan 16 are closed, and the fresh air valve 18, the dehumidification air valve 19, the dehumidification air valve 20, and the return air direct ventilation valve 5 are opened. The return air from the drying and refrigerating dual-purpose room 1 flows out from the return air port 7, and enters the dehumidification air flow waste heat recovery device 15 under the traction of the dehumidification fan 20 to exchange heat with the outdoor fresh air. The return air is discharged to the atmosphere, and the fresh air passes through the return air duct 6, flows through the return air direct ventilation valve 5, and enters the return air heat exchanger 4 for heating. The heated fresh air enters the drying and refrigerating dual-purpose room 1 from the air supply port 2 under the traction of the circulation fan 3; when the return air temperature is high and dehumidification is not required, the fresh air valve 18, the dehumidification air valve 19, the dehumidification fan 20, and the return air direct ventilation valve 5 are closed, and the return air pre-cooling air valve 8 and the fresh air fan 16 are opened. The return air from the drying and refrigerating dual-purpose room 1 flows out from the return air port 7, passes through the return air duct flow 6, passes through the return air pre-cooling air valve 8, and enters the return air pre-cooling device 9 to exchange heat with the outdoor fresh air. The return air after heat exchange enters the return air heat exchanger 4, is heated, and then enters the drying and refrigerating dual-purpose room 1 through the air supply port 2 under the traction of the circulation fan 3. The outdoor fresh air is sent to the fresh air heat exchanger 14 under the traction of the fresh air fan 16;

[0071] Under refrigeration conditions, the exhaust port of compressor 11 is connected to port a of four-way reversing valve 10 via refrigerant pipe 12. Port d of four-way reversing valve 10 is connected to the inlet of fresh air heat exchanger 14 via refrigerant pipe 12. After being compressed by compressor 11, high-temperature, high-pressure refrigerant vapor enters fresh air heat exchanger 14, where it undergoes heat exchange with the outdoor fresh air. This cools the refrigerant and condenses it into liquid refrigerant. The outlet of fresh air heat exchanger 14 is connected to the inlet of wide-pressure-drop ratio bidirectional throttling device 13 via a refrigerant pipe. The refrigerant then passes through refrigeration check valve 1302, refrigeration throttling valve 1301, and the wide-pressure-drop ratio bidirectional throttling device. The outlet of wide-pressure-drop ratio bidirectional throttling device 13 is connected to the inlet of return air heat exchanger 4 via refrigerant pipe 12. The liquid refrigerant exchanges heat with the return air in return air heat exchanger 4, absorbing heat and evaporating into refrigerant vapor, lowering the return air temperature. The refrigerant vapor discharged from the return air heat exchanger 4 passes through the refrigerant pipe 12 and enters the four-way reversing valve 10 at port b of the four-way reversing valve 10, and is then discharged from port c of the four-way reversing valve 10. The refrigerant vapor discharged from port c of the four-way reversing valve 10 enters the compressor 11 from the intake port of the compressor 11, is compressed again, and is then discharged from the exhaust port of the compressor 11.

[0072] Under refrigeration conditions, cold air enters the drying and refrigerating chamber 1, exchanges heat with the refrigerated materials, raising its temperature. It then flows out through the return air vent 7. The supply air temperature and volume are adjusted as needed based on the temperature requirements for refrigeration or preservation. The air in the drying and refrigerating chamber 1 flows out through the return air vent 7, passes through the return air duct 6, and flows through the return air direct ventilation valve 5 into the return air heat exchanger 4. There, it exchanges heat with the refrigerant, lowering its temperature. The air is then drawn by the circulating fan 3 through the supply air vent 2 into the drying and refrigerating chamber 1.

[0073] The specific embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A composite energy system for drying and refrigerating agricultural products in a wide temperature range, characterized in that: Including heat pump system and ventilation system; According to the requirements of refrigeration or drying, the heat pump system performs heat exchange between the refrigerant in the heat pump system and the return air in the ventilation system. The wide pressure drop ratio bidirectional throttling device (13) in the heat pump system increases the heating and cooling temperature range of the heat pump, thereby heating or cooling the return air in the ventilation system. The interface state of the four-way reversing valve (10) in the heat pump system is adjusted to realize the system being in a drying condition or a refrigeration condition. The ventilation system is used to adjust the temperature, air volume and humidity of the return air in the ventilation system according to the temperature and humidity requirements of refrigeration, preservation or drying; the return air pre-cooling device (9) in the ventilation system uses outdoor fresh air as a natural cooling source to reduce the temperature of the return air entering the return air heat exchanger (4); the dehumidified air flow waste heat recovery device (15) in the ventilation system uses outdoor fresh air to recover the waste heat of the dehumidified air flow; The heat pump system comprises: a return air heat exchanger (4), a four-way reversing valve (10), a compressor (11), a refrigerant pipeline (12), a wide pressure drop ratio bidirectional throttling device (13), and a fresh air heat exchanger (14); The four-way reversing valve (10) comprises four interfaces a, b, c, and d, and the interfaces a, b, c, and d of the four-way reversing valve (10) are respectively connected to a refrigerant pipeline; The wide pressure drop ratio bidirectional throttling device (13) comprises a heating throttling valve (1304), a heating one-way valve (1303), a cooling throttling valve (1301), and a cooling one-way valve (1302); The exhaust port of the compressor (11) is connected to the interface a of the four-way reversing valve (10) through the refrigerant pipe (12), the interface b of the reversing valve (10) is connected to the refrigerant inlet of the return air heat exchanger (4) through the refrigerant pipe (12), the refrigerant outlet of the return air heat exchanger (4) is connected to the wide pressure drop ratio two-way throttling device (13) through the refrigerant pipe (12), the wide pressure drop ratio two-way throttling device (13) is connected to the refrigerant inlet of the fresh air heat exchanger (14) through the refrigerant pipe (12), the refrigerant outlet of the fresh air heat exchanger (14) is connected to the interface d of the four-way reversing valve (10) through the refrigerant pipe (12), and the interface c of the four-way reversing valve (10) is connected to the air intake of the compressor (11) through the refrigerant pipe (12); The ventilation system comprises: a drying and refrigeration dual-purpose chamber (1), an air supply port (2), a circulating fan (3), a return air direct ventilation valve I (5), a return air duct (6), a return air port (7), a return air pre-cooling air valve (8), a return air pre-cooling device (9), a dehumidification air flow waste heat recovery device (15), a fresh air fan (16), a fresh air duct (17), a fresh air valve (18), a dehumidification air valve (19), a dehumidification fan (20), and a return air direct ventilation valve II (21); The outlet of the drying and refrigerating chamber (1) is connected to the return air inlet (7), the return air inlet (7) is connected to the inlet of the return air direct ventilation valve II (21) through the return air duct (6), the outlet of the return air direct ventilation valve II (21) is connected to the inlet of the return air direct ventilation valve I (5) through the return air duct (6), the outlet of the return air direct ventilation valve I (5) is connected to the return air inlet of the return air heat exchanger (4) through the return air duct (6), the return air outlet of the return air heat exchanger (4) is connected to the circulation fan (3) through the return air duct (6), the circulation fan (3) is connected to the air supply port (2) through the return air duct (6), and the air supply port (2) is provided on the drying and refrigerating chamber (1); The return air port (7) is simultaneously connected to the inlet of the dehumidification fan (20) through the return air duct (6), the dehumidification fan (20) is connected to the dehumidification air valve (19) through the return air duct (6), the dehumidification air valve (19) is connected to the inlet of the dehumidification air flow waste heat recovery device (15) through the return air duct (6), the outlet of the dehumidification air flow waste heat recovery device (15) is connected to the fresh air valve (18) through the return air duct (6), and the fresh air valve (18) is finally connected to the inlet of the return air direct ventilation valve I (5) through the return air duct (6); The return air direct ventilation valve II (21) outlet is also connected to the return air pre-cooling valve (8) through the return air duct (6), the return air pre-cooling valve (8) is connected to the return air inlet of the return air pre-cooling device (9), and the return air outlet of the return air pre-cooling device (9) is connected to the return air inlet of the return air heat exchanger (4) through the return air duct (6); The fresh air outlet of the return air pre-cooling device (9) is connected to the inlet of the fresh air fan (16) through the fresh air duct (17), and the fresh air fan (16) is connected to the fresh air inlet of the fresh air heat exchanger (14); In the drying condition, the high-temperature and high-pressure refrigerant passes through the refrigerant pipe (12) in sequence through the exhaust port of the compressor (11), the port a of the four-way reversing valve (10), and the port b of the four-way reversing valve (10) and enters the refrigerant inlet of the return air heat exchanger (4); the high-temperature and high-pressure refrigerant vapor enters the return air heat exchanger (4) and exchanges heat with the return air entering the return air heat exchanger (4) from the return air pipe (6) at the same time, the refrigerant temperature decreases and condenses into liquid refrigerant, and the return air temperature increases; The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger (4), the heating one-way valve (1303), the heating throttle valve (1304), and the refrigerant inlet of the fresh air heat exchanger (14) in sequence through the refrigerant pipe (12); the liquid refrigerant enters the fresh air heat exchanger (14) and exchanges heat with the fresh air entering the fresh air heat exchanger (14) from the fresh air pipe (17) at the same time, and the refrigerant temperature rises to refrigerant vapor, and the fresh air temperature rises; the fresh air after heat exchange is discharged into the air; The refrigerant vapor passes through the fresh air heat exchanger (14), the d interface of the four-way reversing valve (10), and the c interface of the four-way reversing valve (10) in sequence, enters the compressor (11), is compressed, and generates high-temperature and high-pressure refrigerant vapor, which is discharged from the exhaust port of the compressor (11); In the drying condition, when the return air temperature is low and dehumidification is not required, close the return air pre-cooling air valve (8), the fresh air air valve (18), the dehumidification air valve (19), and the dehumidification fan (20), and open the return air direct ventilation valve I (5) and the return air direct ventilation valve II (21); The return air in the drying and refrigerating chamber (1) flows out from the return air port (7), then flows through the return air direct ventilation valve II (21) and the return air direct ventilation valve I (5) through the return air duct (6) and enters the return air heat exchanger (4) to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature increases, and the heated return air passes through the return air duct (6) and is pulled by the circulating fan (3) to enter the drying and refrigerating chamber (1) from the air supply port (2) to dry the material. When the return air temperature reaches a certain set value during drying, the return air direct ventilation valve I (5), the fresh air valve (18), the dehumidification valve (19), and the dehumidification fan (20) are closed, and the return air direct ventilation valve II (21), the return air pre-cooling valve (8), and the fresh air fan (16) are opened; The return air in the drying and refrigerating chamber (1) flows out from the return air port (7), then flows through the return air direct ventilation valve II (21), the return air pre-cooling valve (8) in sequence through the return air duct (6), and enters the return air pre-cooling device (9) to exchange heat with the fresh air. The cooled return air enters the return air heat exchanger (4) to exchange heat with the high-temperature and high-pressure refrigerant vapor, and the return air temperature rises. The heated return air enters the drying and refrigerating chamber (1) through the air supply port (2) under the traction of the circulation fan (3), and the fresh air is sent to the fresh air heat exchanger (14) under the traction of the fresh air fan (16); When dehumidification is required under dry conditions, close the return air pre-cooling air valve (8) and the return air direct ventilation valve II (21), and open the return air direct ventilation valve I (5), the fresh air valve (18), the dehumidification air valve (19), and the dehumidification fan (20); The return air in the drying and refrigeration chamber (1) flows out from the return air port (7), and then enters the dehumidification air flow waste heat recovery device (15) through the return air duct (6) under the traction of the dehumidification fan (20) through the dehumidification air valve (19) to exchange heat with the outdoor fresh air. The return air after heat exchange is discharged to the atmosphere. The fresh air flows through the return air duct (6) through the fresh air valve (18) and the return air direct ventilation valve I (5) to enter the return air heat exchanger (4) to exchange heat with the high-temperature and high-pressure refrigerant vapor. The return air temperature rises. The heated return air enters the drying and refrigeration chamber (1) through the air supply port (2) under the traction of the circulation fan (3) to achieve the purpose of drying the materials and dehumidifying the return air.

2. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: The wide pressure drop ratio bidirectional throttling device (13) is used to increase the temperature range of the heat pump so that the system can meet the temperature required for drying or refrigeration preservation. When the system is in a drying condition, the refrigerant passes through the heating check valve (1303) and the heating throttle valve (1304) in the wide pressure drop ratio bidirectional throttling device (13) in sequence; when the system is in a refrigeration preservation condition, the refrigerant passes through the cooling check valve (1302) and the cooling throttle valve (1301) in the wide pressure drop ratio bidirectional throttling device (13) in sequence.

3. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: In the refrigeration mode, the high-temperature and high-pressure refrigerant passes through the refrigerant pipe (12) in sequence through the exhaust port of the compressor (11), the port a of the four-way reversing valve (10), and the port d of the four-way reversing valve (10) to enter the refrigerant inlet of the fresh air heat exchanger (14); the high-temperature and high-pressure refrigerant vapor enters the fresh air heat exchanger (14) and exchanges heat with the fresh air entering the fresh air heat exchanger (14) from the fresh air pipe (17) at the same time, the refrigerant temperature decreases and condenses into liquid refrigerant, and the fresh air temperature increases; the fresh air after heat exchange is discharged into the air; The liquid refrigerant passes through the refrigerant outlet of the fresh air heat exchanger (14), the refrigeration one-way valve (1302), the refrigeration throttle valve (1301), and the refrigerant inlet of the return air heat exchanger (4) through the refrigerant pipe (12); the liquid refrigerant enters the return air heat exchanger (4) and exchanges heat with the return air entering the return air heat exchanger (4) from the return air pipe (6) at the same time, the refrigerant temperature increases to refrigerant vapor, and the return air temperature decreases; The refrigerant vapor passes through the outlet of the return air heat exchanger (4), the port b of the four-way reversing valve (10), and the port c of the four-way reversing valve (10) in sequence, enters the compressor (11) for compression, and generates high-temperature and high-pressure refrigerant vapor which is discharged from the exhaust port of the compressor (11).

4. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: In the cold storage mode, the return air pre-cooling air valve (8), the fresh air air valve (18), the dehumidification air valve (19), and the dehumidification fan (20) are closed, and the return air direct ventilation valve I (5) and the return air direct ventilation valve II (21) are opened; The return air in the drying and refrigerating chamber (1) flows out from the return air port (7), then flows through the return air direct ventilation valve II (21) and the return air direct ventilation valve I (5) through the return air duct (6) and enters the return air heat exchanger (4) to exchange heat with the liquid refrigerant. The return air temperature is reduced, and the cooled return air is drawn by the circulating fan (3) and enters the drying and refrigerating chamber (1) from the air supply port (2) to refrigerate the materials.

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