Agricultural product drying and cold storage fresh-keeping composite energy system with wide temperature area

Abstract

The invention relates to a wide-temperature-zone agricultural product drying and cold storage preservation composite energy system, and belongs to the technical field of agricultural product drying and cold storage preservation. The system comprises a heat pump system and a ventilation system, according to the requirement of refrigeration or drying, a refrigerant in the heat pump system exchanges heat with return air in the ventilation system, and the return air in the ventilation system is heated or cooled; the ventilation system is used for adjusting the temperature, the air supply amount and the humidity of return air in the ventilation system as required according to the temperature and humidity requirements of refrigeration preservation or drying; the return air pre-cooling device in the ventilation system takes outdoor fresh air as a natural cold source, the temperature of inlet return air is reduced, refrigerant steam is fully condensed, and the heating performance and the operation stability of a heat pump are improved; the temperature range provided by the heat pump is enlarged, and the requirement for drying or refrigeration is met; after agricultural products needing to be dried are processed, the drying chamber can be used as a refrigerating chamber, investment is reduced, and the equipment utilization rate is increased.

Description

Technical Field

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

[0002] Heat pump drying is widely used in the field of agricultural product processing and is applied in various regions across the country. In some places where agricultural products are produced, there are products that need to be processed and dried for primary processing, as well as products that need to be refrigerated and preserved. The equipment currently used for drying or refrigerating agricultural products has the problems of single function and low utilization rate. In addition, if drying equipment and refrigerating and preserving equipment are equipped at the production site at the same time, not only will the initial investment be high and the investment recovery period be too long, but the equipment maintenance cost will also be high. After installing a wide temperature range agricultural product drying and refrigerating and preserving composite energy system, after the agricultural products that need to be dried are processed, the drying room can be converted into a refrigerating room to achieve the purpose of reducing investment and improving equipment utilization.

[0003] The current heat pump system is difficult to meet the heating requirements of drying or refrigeration, and heat pump drying also has some shortcomings. During the material drying process, when the return air temperature is too high, the refrigerant vapor in the condenser is difficult to condense effectively, which will cause the heating performance of the heat pump system to decay rapidly and the system to operate unstably. At the same time, a large amount of high-temperature and high-humidity airflow is directly discharged into the atmosphere, and the waste heat is not recovered and wasted seriously. Summary of the invention

[0004] In view of the problems and shortcomings of the equipment currently used for drying or refrigerating agricultural products, the present invention provides a composite energy system for drying and refrigerating agricultural products in a wide temperature range. The system of the present invention can convert the drying room into a refrigerating room after the agricultural products to be dried are processed, thereby reducing investment and improving equipment utilization. The precooling device uses outdoor fresh air as a natural cold source to reduce the return air temperature entering the return air heat exchanger, so that the refrigerant vapor therein is fully condensed, reducing throttling losses and increasing the heat release of the refrigerant in the return air heat exchanger, thereby improving the heating performance and operating stability of the heat pump. The dehumidification airflow waste heat recovery device uses outdoor fresh air to recover the dehumidification airflow waste heat, reducing heat energy loss and reducing 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] 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 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 a drying condition or a 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 cold storage, 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 operating stability of the heat pump; the dehumidification airflow waste heat recovery device 15 in the ventilation system recovers the dehumidification airflow waste heat with outdoor fresh air.

[0008] As a further solution of the present invention, 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;

[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 comprises a heating throttling valve 1304, a heating check valve 1303, a cooling throttling 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 solution of the present invention, the ventilation system includes: a drying and refrigerating dual-purpose chamber 1, an air supply port 2, a circulating fan 3, a return air direct ventilation valve I5, a return air duct 6, a return air port 7, a return air precooling air valve 8, a return air precooling 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 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 arranged on the drying and refrigerating 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 Ⅰ5 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 the energy consumption of the drying system;

[0015] The return air direct air valve II 21 outlet is also connected to the return air precooling valve 8 through the return air duct 6, the return air precooling valve 8 is connected to the return air inlet of the return air precooling device 9, and the return air outlet of the return air precooling 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 precooling 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. The return air precooling device 9 uses the outdoor fresh air as a natural cooling source to reduce the return air temperature entering the return air heat exchanger, so that the refrigerant vapor therein is fully condensed, thereby improving the heating performance and operation stability of the heat pump.

[0017] As a further solution of the present invention, the wide pressure drop ratio two-way 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 the drying condition, the refrigerant passes through the heating check 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 the refrigeration preservation condition, the refrigerant passes through the refrigeration check valve 1302 and the refrigeration throttle valve 1301 in the wide pressure drop ratio two-way throttling device 13 in sequence. According to the required temperature range for drying, the type and model of the heating throttle valve 1304 are selected; according to the required temperature range for refrigeration preservation, the type and model of the refrigeration throttle valve 1301 are selected; thereby meeting the temperature range of the composite energy system for drying and refrigeration preservation of agricultural products in a wide temperature range.

[0018] As a further solution of the present invention, 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 a interface of the four-way reversing valve 10, and the b interface of the four-way reversing valve 10 to enter 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;

[0019] The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger 4, the heating check 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 to perform heat exchange 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;

[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 that 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 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 I5 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 steam. 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 circulating fan 3 to dry the material.

[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 air 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 operation 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 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 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 refrigerating 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, and exchanges heat 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 flows through the return air duct 6 through the fresh air valve 18 and the return air direct ventilation valve Ⅰ5 to enter the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor, and the return air temperature increases. 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 to achieve the purpose of drying the materials and dehumidifying the return air.

[0027] As a further solution of the present invention, in the refrigeration 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 a interface of the four-way reversing valve 10, and the d interface 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 that simultaneously enters the fresh air heat exchanger 14 from the fresh air pipe 17, 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;

[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 in sequence through the refrigerant pipe 12; the liquid refrigerant enters the return air heat exchanger 4 to exchange 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 that is discharged from the exhaust port of the compressor 11.

[0030] As a further solution of the present invention, in the refrigeration condition, the return air pre-cooling air valve 8, the fresh 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 I5 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, and the cooled return air enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulating fan 3 to refrigerate the materials.

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

[0033] 1. Use a wide pressure drop ratio bidirectional 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 dehumidification airflow waste heat recovery device to recover the waste heat of the dehumidification 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 to reduce investment and improve 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 schematic diagram of a wide pressure drop ratio bidirectional throttling device.

[0039] Figure 1The reference numerals represent in sequence: 1-drying and refrigerating chamber, 2-air supply port, 3-circulating fan, 4-return air heat exchanger, 5-return air direct ventilation valve I, 6-return air duct, 7-return air port, 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-dehumidification air flow waste heat recovery device, 16-fresh air fan, 17-fresh air duct, 18-fresh air valve, 19-dehumidification air valve, 20-dehumidification fan, 21-return air direct ventilation valve II;

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

[0041] The present invention will be further described below in conjunction with 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] 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 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 a drying condition or a 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 cold storage, 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 operating stability of the heat pump; the dehumidification airflow waste heat recovery device 15 in the ventilation system recovers the dehumidification airflow waste heat with outdoor fresh air.

[0045] As a further solution of the present invention, 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;

[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 comprises a heating throttling valve 1304, a heating check valve 1303, a cooling throttling 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 solution of the present invention, the ventilation system includes: a drying and refrigerating dual-purpose chamber 1, an air supply port 2, a circulating fan 3, a return air direct ventilation valve I5, a return air duct 6, a return air port 7, a return air precooling air valve 8, a return air precooling 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 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 arranged on the drying and refrigerating 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 Ⅰ5 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 the energy consumption of the drying system;

[0052] The return air direct air valve II 21 outlet is also connected to the return air precooling valve 8 through the return air duct 6, the return air precooling valve 8 is connected to the return air inlet of the return air precooling device 9, and the return air outlet of the return air precooling 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 precooling 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. The return air precooling device 9 uses the outdoor fresh air as a natural cooling source to reduce the return air temperature entering the return air heat exchanger, so that the refrigerant vapor therein is fully condensed, thereby improving the heating performance and operation 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 check 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 check 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 solution of the present invention, 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 a interface of the four-way reversing valve 10, and the b interface of the four-way reversing valve 10 to enter 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;

[0056] The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger 4, the heating check 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 to perform heat exchange 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;

[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 that 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 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 I5 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 steam. 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 circulating fan 3 to dry the material.

[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 air 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 operation 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 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 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 refrigerating 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, and exchanges heat 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 flows through the return air duct 6 through the fresh air valve 18 and the return air direct ventilation valve Ⅰ5 to enter the return air heat exchanger 4 to exchange heat with the high-temperature and high-pressure refrigerant vapor, and the return air temperature increases. 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 to achieve the purpose of drying the materials and dehumidifying the return air.

[0064] As a further solution of the present invention, in the refrigeration 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 a interface of the four-way reversing valve 10, and the d interface 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 that simultaneously enters the fresh air heat exchanger 14 from the fresh air pipe 17, 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;

[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 in sequence through the refrigerant pipe 12; the liquid refrigerant enters the return air heat exchanger 4 to exchange 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 that is discharged from the exhaust port of the compressor 11.

[0067] As a further solution of the present invention, in the refrigeration condition, the return air pre-cooling air valve 8, the fresh 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 I5 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, and the cooled return air enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulating fan 3 to refrigerate the materials.

[0069] When the system is in a drying condition, the exhaust port of the compressor 11 is connected to the port a of the four-way reversing valve 10 through the refrigerant pipe 12, and the port b of the four-way reversing valve 10 is connected to the inlet of the return air heat exchanger 4 through the refrigerant pipe 12. The high-temperature and high-pressure refrigerant vapor compressed by the compressor 11 enters the return air heat exchanger 4 and performs heat exchange with the return air from the return air pipe 6. The refrigerant temperature is reduced and condensed into liquid refrigerant. The return air temperature is increased and enters the drying and refrigeration dual-purpose chamber 1 from the air supply port 2. The outlet of the return air heat exchanger 4 is connected to the inlet of the wide pressure drop ratio two-way throttling device 13 through the refrigerant pipe 12. The refrigerant passes through the heating check valve 1303 and the heating throttling valve 1304 in turn. 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 through the refrigerant pipe. The liquid refrigerant performs heat exchange with the outdoor fresh air in the fresh air heat exchanger 14, and the liquid refrigerant absorbs heat and evaporates into refrigerant vapor. The refrigerant vapor discharged from the fresh air heat exchanger 14 enters the four-way reversing valve 10 at the port d of the four-way reversing valve 10 through the refrigerant pipe 12, and then is 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 air intake port of the compressor 11, 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 of 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 circulating 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 fan 20, and the return air direct ventilation valve 5 are opened. The return air of 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 flows through the return air duct 6 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 circulating 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 of the drying and refrigerating dual-purpose room 1 flows out from the return air port 7, flows through the return air duct 6 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 for heating, and then enters the drying and refrigerating dual-purpose room 1 through the air supply port 2 under the traction of the circulating fan 3, and the outdoor fresh air is sent to the fresh air heat exchanger 14 under the traction of the fresh air fan 16;

[0071] Under the refrigeration condition, the exhaust port of the compressor 11 is connected to the port a of the four-way reversing valve 10 through the refrigerant pipe 12, and the port d of the four-way reversing valve 10 is connected to the inlet of the fresh air heat exchanger 14 through the refrigerant pipe 12. The high-temperature and high-pressure refrigerant vapor compressed by the compressor 11 enters the fresh air heat exchanger 14 to exchange heat with the outdoor fresh air, and the refrigerant temperature is reduced and condensed into liquid refrigerant. The outlet of the fresh air heat exchanger 14 is connected to the inlet of the wide pressure drop ratio two-way throttling device 13 through the refrigerant pipe, and the refrigerant passes through the refrigeration check valve 1302 and the refrigeration throttling valve 1301 through the wide pressure drop ratio two-way throttling device in turn, and the outlet of the wide pressure drop ratio two-way throttling device 13 is connected to the inlet of the return air heat exchanger 4 through the refrigerant pipe 12. The liquid refrigerant and the return air exchange heat in the return air heat exchanger 4, and the liquid refrigerant absorbs heat and evaporates into refrigerant vapor, and the return air temperature is reduced. The refrigerant vapor discharged from the return air heat exchanger 4 enters the four-way reversing valve 10 at the port b of the four-way reversing valve 10 through the refrigerant pipe 12, and then is 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 air intake port of the compressor 11, is compressed again, and is discharged from the exhaust port of the compressor 11.

[0072] Under refrigeration conditions, cold air enters the drying and refrigerating chamber 1 to exchange heat with the refrigerated materials, the temperature rises, and then flows out at the return air port 7. According to the temperature requirements of refrigeration or preservation, the air supply temperature and air supply volume are adjusted as needed. The air in the drying and refrigerating chamber 1 flows out at the return air port 7, flows through the return air pipe 6 and the return air direct ventilation valve 5 into the return air heat exchanger 4, exchanges heat with the refrigerant in the return air heat exchanger 4 to reduce the temperature, and then enters the drying and refrigerating chamber 1 from the air supply port 2 under the traction of the circulating fan 3.

[0073] The specific embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose 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 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 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 as required according to the temperature and humidity requirements of cold storage, preservation or drying; the return air precooling 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); 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.

2. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: 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 non-return valve (1303), a cooling throttling valve (1301), and a cooling non-return valve (1302); The exhaust port of the compressor (11) is connected to the a interface of the four-way reversing valve (10) through a refrigerant pipeline (12); the b interface of the reversing valve (10) is connected to the refrigerant inlet of the return air heat exchanger (4) through a refrigerant pipeline (12); the refrigerant outlet of the return air heat exchanger (4) is connected to a wide pressure drop ratio bidirectional throttling device (13) through a refrigerant pipeline (12); the wide pressure drop ratio bidirectional throttling device (13) is connected to the refrigerant inlet of the fresh air heat exchanger (14) through a refrigerant pipeline (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 a refrigerant pipeline (12); and the c interface of the four-way reversing valve (10) is connected to the air intake port of the compressor (11) through a refrigerant pipeline (12).

3. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: The ventilation system comprises: a drying and refrigerating 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 port (7), the return air port (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 arranged 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 precooling valve (8) through the return air duct (6), the return air precooling valve (8) is connected to the return air inlet of the return air precooling device (9), and the return air outlet of the return air precooling 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 precooling device (9) is connected to the inlet of the fresh air fan (16) through 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).

4. 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 two-way throttling device (13) is used to increase 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 check valve (1303) and the heating throttling 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 check valve (1302) and the refrigeration throttling valve (1301) in the wide pressure drop ratio two-way throttling device (13) in sequence.

5. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: 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 a interface of the four-way reversing valve (10), and the b interface of the four-way reversing valve (10) to enter 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 simultaneously entering the return air heat exchanger (4) from the return air pipe (6); the refrigerant temperature is reduced and condensed into liquid refrigerant, and the return air temperature is increased; The liquid refrigerant passes through the refrigerant outlet of the return air heat exchanger (4), the heating non-return 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 that simultaneously enters the fresh air heat exchanger (14) from the fresh air pipe (17); the temperature of the refrigerant rises to become refrigerant vapor, and the temperature of the fresh air 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) for compression, and generates high-temperature and high-pressure refrigerant vapor which is discharged from the exhaust port of the compressor 11.

6. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: In the dry 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 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 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 circulating fan (3) to dry the material.

7. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: 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 air valve (19), and the dehumidification fan (20) are closed, and the return air direct ventilation valve II (21), the return air pre-cooling air 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 air 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. The return air temperature increases. 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 delivered to the fresh air heat exchanger (14) under the traction of the fresh air fan (16).

8. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: When dehumidification is required under dry 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; The return air in the drying and refrigerating chamber (1) flows out from the return air port (7), and then enters the dehumidifying air flow waste heat recovery device (15) through the return air duct (6) under the traction of the dehumidifying fan (20), passes through the dehumidifying air valve (19), and exchanges 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), passes through the fresh air valve (18), and the return air direct ventilation valve I (5) 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. The heated return air enters the drying and refrigerating chamber (1) through the air supply port (2) under the traction of the circulating fan (3), thereby achieving the purpose of drying the materials and dehumidifying the return air.

9. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: In the refrigeration 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 a interface of the four-way reversing valve (10), and the d interface 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) to perform heat exchange with the fresh air simultaneously entering the fresh air heat exchanger (14) from the fresh air pipe (17); the refrigerant temperature is reduced and condensed into liquid refrigerant, and the fresh air temperature is increased; 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 non-return valve (1302), the refrigeration throttle valve (1301), and the refrigerant inlet of the return air heat exchanger (4) in sequence through the refrigerant pipeline (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 become 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.

10. The wide temperature range agricultural product drying and refrigeration preservation composite energy system according to claim 1, characterized in that: In the cold storage condition, the return air pre-cooling air valve (8), the fresh 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, and the return air temperature is reduced. 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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