Multi-loop heat pump drying system with adjustable return air ratio

Abstract

The invention relates to a multi-loop heat pump drying system with an adjustable return air ratio. Comprising an air inlet, an air outlet, a heating pipeline, a drying pipeline, a refrigeration pipeline, a first air return pipeline, a second air return pipeline, a third air return pipeline, a first air valve, a second air valve, a third air valve, a fourth air valve, a fifth air valve, a sixth air valve, a dryer, a fan, a hot water coil pipe, a cold water coil pipe, a heat circulation device and a controller. The first air return pipeline, the second air return pipeline and the third air return pipeline form a plurality of loops, the air valves are arranged in the different pipelines, and the air return ratio in the system and the dehumidification and heating degree of return air are controlled by controlling opening and closing of the air valves. Namely, according to the technical scheme, the air return ratio can be adjusted by opening and closing the air valves according to outdoor temperature and humidity changes in different seasons, and the drying requirements under different conditions are met.

Description

Technical Field

[0001] The present application relates to the field of energy-saving drying technology, and in particular to a multi-circuit heat pump drying system with adjustable return air ratio. Background Art

[0002] The drying industry involves a wide range of areas in the national economy, such as agriculture, food, chemicals, ceramics, medicine, mineral processing, pulp and paper, wood processing and other industries. Drying is used in almost all production processes. The outdoor temperature and humidity are different in different seasons. The existing drying system is difficult to adjust the return air ratio according to the changes in outdoor temperature and humidity in different seasons to meet the drying needs in different situations. Summary of the invention

[0003] In order to at least overcome to some extent the problem that the drying system in the related art is difficult to adjust the return air ratio according to the changes in outdoor temperature and humidity in different seasons to meet the drying needs in different situations, the present application provides a multi-circuit adjustable return air ratio heat pump drying system.

[0004] The scheme of this application is as follows:

[0005] A multi-circuit heat pump drying system with adjustable return air ratio, comprising:

[0006] Air inlet, air outlet, heating duct, drying duct, refrigeration duct, first return air duct, second return air duct, third return air duct, first air valve, second air valve, third air valve, fourth air valve, fifth air valve, sixth air valve, dryer, fan, hot water coil, cold water coil and heat circulation device;

[0007] The heating pipe comprises a first connection port, a second connection port and a third connection port;

[0008] The refrigeration pipeline includes a first connection port, a second connection port and a third connection port;

[0009] The first return air duct includes a first connection port, a second connection port and a third connection port;

[0010] The second return air duct includes a first connection port, a second connection port and a third connection port;

[0011] The third return air duct includes a first connection port and a second connection port;

[0012] The first connection port of the heating duct is connected to the air inlet and the first connection port of the first return air duct, the second connection port is connected to the first connection port of the second return air duct, and the third connection port is connected to the drying duct;

[0013] The first connection port of the refrigeration pipe is connected to the air outlet and the third connection port of the first return air pipe, the second connection port is connected to the third connection port of the second return air pipe, and the third connection port is connected to the drying pipe;

[0014] The second connection port of the first return air duct is connected to the first connection port of the third return air duct;

[0015] The second connecting port of the second return air duct is connected to the second connecting port of the third return air duct;

[0016] The first air valve is arranged at the air inlet;

[0017] The second air valve is arranged at the air outlet;

[0018] The third air valve is arranged between the second connection port and the third connection port of the first return air duct;

[0019] The fourth air valve is arranged between the first connection port and the second connection port of the third return air duct;

[0020] The fifth air valve is arranged between the first connection port and the second connection port of the second return air duct;

[0021] The sixth air valve is arranged between the second connecting port and the third connecting port of the second return air duct;

[0022] The dryer is arranged in the drying pipeline and is used to dry the gas flowing through the dryer;

[0023] The fan is arranged between the second connection port and the third connection port of the refrigeration pipeline;

[0024] The thermal circulation device is connected to the hot water coil and the cold water coil;

[0025] The hot water coil is arranged between the first connection port and the second connection port of the heating pipe, and is used to heat the gas in the heating pipe;

[0026] The cold water coil is arranged between the first connecting port and the second connecting port of the refrigeration pipeline, and is used for absorbing heat from the gas in the refrigeration pipeline.

[0027] Preferably, the thermal cycler comprises:

[0028] Hot water circulation pipeline, heat exchange pipeline, cold water circulation pipeline, first water pump, second water pump, condenser, evaporator, compressor and throttle valve;

[0029] The thermal cycle device uses water as an energy carrier;

[0030] The hot water coil is connected to the condenser through the hot water circulation pipeline;

[0031] The first water pump is arranged in the hot water circulation pipeline;

[0032] The cold water coil is connected to the evaporator through the cold water circulation pipeline;

[0033] The second water pump is arranged in the cold water circulation pipeline;

[0034] The heat exchange pipe is composed of four parts, the first part is arranged in the condenser, the second part is arranged in the evaporator, the energy carrier in the third part flows from the evaporator to the condenser, and the energy carrier in the fourth part flows from the condenser to the evaporator;

[0035] The compressor is disposed in the third portion of the heat exchange pipe;

[0036] The throttle valve is disposed in a fourth portion of the heat exchange pipe.

[0037] Preferably, the thermal cycler comprises:

[0038] Hot water circulation pipes, heat exchange pipes, cold water circulation pipes, condensers, evaporators, compressors and throttle valves;

[0039] The thermal cycle device uses a refrigerant as an energy carrier;

[0040] The condenser is arranged at the hot water coil;

[0041] The evaporator is arranged at the cold water coil;

[0042] The heat exchange pipe is composed of two parts, the energy carrier in the first part flows from the evaporator to the condenser, and the energy carrier in the second part flows from the condenser to the evaporator;

[0043] The compressor is disposed in the first portion of the heat exchange conduit;

[0044] The throttle valve is disposed in the second portion of the heat exchange pipe.

[0045] Preferably, it also includes:

[0046] Controller;

[0047] The controller is connected to each air valve and is used to control the switch of each air valve according to the received working condition instruction, so as to control the return air ratio in the system, and the dehumidification and heating degree of the return air;

[0048] The third air valve is close to the third connecting port of the first return air duct;

[0049] The fourth air valve is close to the second connecting port of the third return air duct;

[0050] The fifth air valve is close to the second connecting port of the second return air duct;

[0051] The sixth air valve is close to the second connecting port of the second return air duct.

[0052] Preferably, when receiving the first operating condition instruction, the controller controls the third air valve to open, and controls the first air valve, the second air valve, the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to 100%, and all the return air is dehumidified and heated.

[0053] Preferably, when receiving the second operating condition instruction, the controller controls the first air valve, the second air valve and the third air valve to open, and controls the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to 50%, and all the return air is dehumidified and heated.

[0054] Preferably, when receiving the third operating condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fourth air valve and the sixth air valve to open, and controls the fifth air valve to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and all the return air is heated.

[0055] Preferably, when receiving the fourth operating condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fourth air valve and the fifth air valve to open, and controls the sixth air valve to close, so as to control the return air ratio in the system to 50%, all the return air is dehumidified, and part of the return air is heated.

[0056] Preferably, when receiving the fifth operating condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fifth air valve and the sixth air valve to open, and controls the fourth air valve to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and part of the return air is heated.

[0057] Preferably, when receiving the sixth operating condition instruction, the controller controls the first air valve and the second air valve to open, and controls the third air valve, the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to 0%, all return air is dehumidified, and all fresh air is heated.

[0058] The technical solution provided by this application may have the following beneficial effects:

[0059] The multi-circuit adjustable return air ratio heat pump drying system in this technical solution forms multiple circuits through the first return air duct, the second return air duct and the third return air duct, and sets air valves in different ducts. By controlling the switch of each air valve, the return air ratio in the system and the dehumidification and heating degree of the return air can be controlled. That is, this technical solution can adjust the return air ratio by switching each air valve according to the changes in outdoor temperature and humidity in different seasons to meet the drying needs in different situations.

[0060] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0062] Figure 1 It is a structural schematic diagram of a multi-circuit adjustable return air ratio heat pump drying system provided by an embodiment of the present application;

[0063] Figure 2 It is a structural schematic diagram of a multi-circuit adjustable return air ratio heat pump drying system provided by another embodiment of the present application;

[0064] Figure 3 It is a gas flow diagram of a multi-circuit adjustable return air ratio heat pump drying system under a first working condition provided by an embodiment of the present application;

[0065] Figure 4 It is a schematic diagram of gas flow direction of a multi-circuit adjustable return air ratio heat pump drying system under a second working condition provided by an embodiment of the present application;

[0066] Figure 5 It is a schematic diagram of gas flow direction of a multi-circuit adjustable return air ratio heat pump drying system under a third working condition provided by an embodiment of the present application;

[0067] Figure 6 It is a schematic diagram of gas flow direction of a multi-circuit adjustable return air ratio heat pump drying system under a fourth working condition provided by an embodiment of the present application;

[0068] Figure 7 It is a schematic diagram of gas flow direction of a multi-circuit adjustable return air ratio heat pump drying system under the fifth working condition provided by an embodiment of the present application;

[0069] Figure 8 It is a schematic diagram of gas flow of a multi-circuit adjustable return air ratio heat pump drying system under the sixth operating condition provided by an embodiment of the present application.

[0070] Figure numerals: air inlet-11; air outlet-12; heating duct-21; drying duct-22; refrigeration duct-23; first return air duct-31; second return air duct-32; third return air duct-33; first air valve-41; second air valve-42; third air valve-43; fourth air valve-44; fifth air valve-45; sixth air valve-46; dryer-5; fan-6; hot water coil-71; cold water coil-72; hot water circulation duct-81; heat exchange duct-82; cold water circulation duct-83; first water pump-84; second water pump-85; condenser-86; evaporator-87; compressor-88; throttle valve-89. DETAILED DESCRIPTION

[0071] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0072] Embodiment 1

[0073] Figure 1 This is a schematic diagram of a multi-circuit adjustable return air ratio heat pump drying system provided by an embodiment of the present application, referring to Figure 1 , a multi-circuit adjustable return air ratio heat pump drying system, comprising:

[0074] Air inlet 11, air outlet 12, heating duct 21, drying duct 22, refrigeration duct 23, first return air duct 31, second return air duct 32, third return air duct 33, first air valve 41, second air valve 42, third air valve 43, fourth air valve 44, fifth air valve 45, sixth air valve 46, dryer 5, fan 6, hot water coil 71, cold water coil 72, thermal circulation device and controller;

[0075] The heating pipe 21 includes a first connection port, a second connection port and a third connection port;

[0076] The refrigeration pipe 23 includes a first connection port, a second connection port and a third connection port;

[0077] The first return air duct 31 includes a first connection port, a second connection port and a third connection port;

[0078] The second return air duct 32 includes a first connection port, a second connection port and a third connection port;

[0079] The third return air duct 33 includes a first connection port and a second connection port;

[0080] The first connection port of the heating duct 21 is connected to the air inlet 11 and the first connection port of the first return air duct 31 , the second connection port is connected to the first connection port of the second return air duct 32 , and the third connection port is connected to the drying duct 22 ;

[0081] The first connection port of the refrigeration pipe 23 is connected to the air outlet 12 and the third connection port of the first return air pipe 31 , the second connection port is connected to the third connection port of the second return air pipe 32 , and the third connection port is connected to the drying pipe 22 ;

[0082] The second connection port of the first return air duct 31 is connected to the first connection port of the third return air duct 33;

[0083] The second connection port of the second return air duct 32 is connected to the second connection port of the third return air duct 33;

[0084] The first air valve 41 is arranged at the air inlet 11;

[0085] The second air valve 42 is disposed at the air outlet 12;

[0086] The third air valve 43 is disposed between the second connection port and the third connection port of the first return air duct 31;

[0087] The fourth air valve 44 is disposed between the first connection port and the second connection port of the third return air duct 33;

[0088] The fifth air valve 45 is disposed between the first connection port and the second connection port of the second return air duct 32;

[0089] The sixth air valve 46 is disposed between the second connection port and the third connection port of the second return air duct 32;

[0090] The dryer 5 is disposed in the drying pipeline 22 and is used to dry the gas flowing through the dryer 5;

[0091] The fan 6 is arranged between the second connection port and the third connection port of the refrigeration pipe 23;

[0092] The heat circulation device connects the hot water coil 71 and the cold water coil 72;

[0093] The hot water coil 71 is disposed between the first connection port and the second connection port of the heating pipe 21, and is used to heat the gas in the heating pipe 21;

[0094] The cold water coil 72 is disposed between the first connection port and the second connection port of the refrigeration pipe 23, and is used to absorb heat from the gas in the refrigeration pipe 23;

[0095] The controller is connected to each air valve and is used to control the switch of each air valve according to the received working condition instructions to control the return air ratio in the system, as well as the dehumidification and heating degree of the return air.

[0096] It should be noted that the first connection port, the second connection port and the third connection port of the heating pipe 21 are Figure 1 The figure shows three connection ports of the heating pipe 21 from left to right.

[0097] The first connection port, the second connection port and the third connection port of the refrigeration pipe 23 are Figure 1 The figure shows three connection ports of the refrigeration pipe 23 from left to right.

[0098] The first connection port, the second connection port and the third connection port of the first return air duct 31 are Figure 1 The figure shows three connection ports of the first return air duct 31 from top to bottom.

[0099] The first connection port, the second connection port and the third connection port of the second return air duct 32 are Figure 1 The figure shows three connection ports of the second return air duct 32 from top to bottom.

[0100] The first connection port and the second connection port of the third return air duct 33 are Figure 1 The two connection ports of the third return air duct 33 from left to right are shown in FIG.

[0101] The role of the air valve in this system is to adjust the path and flow of air flow, which has a direct impact on the energy efficiency and performance of the entire drying process. It not only provides the necessary air flow control, but also accurately controls the drying conditions by adjusting the air volume and flow direction, thereby improving drying efficiency and product quality.

[0102] In specific practice, refer to Figure 1 , the third air valve 43 is close to the third connecting port of the first return air duct 31;

[0103] The fourth air valve 44 is close to the second connection port of the third return air duct 33;

[0104] The fifth air valve 45 is close to the second connection port of the second return air duct 32;

[0105] The sixth air valve 46 is close to the second connecting port of the second return air duct 32 .

[0106] By placing each air valve close to the connection port, the return air can achieve a "direct current" effect and prevent excessive return air from entering a "dead end" and affecting the flow rate.

[0107] The dryer 5 is the final user of the heat pump drying system, and its main function is to absorb moisture from the material. Through the heat pump drying system, the cooling and dehumidifying effect of the evaporator 87 and the heat release effect of the condenser 86 on the air, dry air with a lower water content is obtained to dry the wet material.

[0108] The function of the fan 6 is to promote air flow and ensure that heat and moisture circulate effectively in the system.

[0109] The main function of the cold water coil 72 is to reduce the wet temperature of the air. The cold water and the dry air exchange heat in the cold water coil 72, dehumidify the dry air and recover the heat therein.

[0110] The main function of the hot water coil 71 is to release heat and increase the temperature of the air to meet the heat demand for material drying.

[0111] During implementation, the system introduces ambient air or return air from the dryer 5 , which is heated by the hot water coil 71 to dry the material. The dried air is discharged from the system through the fan 6 , and is cooled by the cold water coil 72 .

[0112] The multi-circuit adjustable return air ratio heat pump drying system in the technical solution forms multiple circuits through the first return air duct 31, the second return air duct 32 and the third return air duct 33, and sets air valves in different ducts. By controlling the switch of each air valve, the return air ratio in the system and the dehumidification and heating degree of the return air can be controlled. That is, the technical solution can adjust the return air ratio by switching each air valve according to the changes in outdoor temperature and humidity in different seasons to meet the drying needs in different situations.

[0113] Embodiment 2

[0114] Traditional drying operation is a high energy consumption process. The energy consumed by drying in my country accounts for about 12% of the total energy consumption of the national economy each year. At the same time, the traditional drying process is also a factor that causes environmental pollution. In order to cope with energy and environmental problems and achieve sustainable development of the national economy, energy saving and environmental protection of drying are becoming increasingly important. The traditional drying industry is also facing industrial transformation and upgrading. As a clean and energy-saving technology that takes into account the quality and cost of drying products, the loop adjustable return air ratio heat pump drying system is applied in the drying field, which can greatly reduce the energy consumption cost of enterprises and achieve the goal of energy saving and emission reduction.

[0115] In order to solve the problem of high energy consumption of the drying process in the existing drying system, the heat cycle device is innovated in this embodiment, and the heat pump technology is adopted to recover the heat in the high-temperature drying flue gas after the dryer 5 by using water or refrigerant as the energy carrier. After the heat pump is lifted, high-temperature refrigerant or high-temperature hot water is obtained to replace the fossil fuel heat source and be used to heat the fresh air introduced from the environment. At the same time, according to different materials and different seasons of outdoor temperature and humidity changes, the proportion of supply and exhaust air can be adjusted by switching on and off each air valve to match the drying needs.

[0116] It should be noted that there are many ways to implement the thermal cycle device. For example, a thermal cycle device using water as an energy carrier Figure 1 As shown, including:

[0117] Hot water circulation pipeline 81, heat exchange pipeline 82, cold water circulation pipeline 83, first water pump 84, second water pump 85, condenser 86, evaporator 87, compressor 88 and throttle valve 89;

[0118] The hot water coil 71 is connected to the condenser 86 via the hot water circulation pipe 81;

[0119] The first water pump 84 is disposed in the hot water circulation pipe 81;

[0120] The cold water coil 72 is connected to the evaporator 87 through the cold water circulation pipe 83;

[0121] The second water pump 85 is disposed in the cold water circulation pipeline 83;

[0122] The heat exchange pipe 82 is composed of four parts, the first part is arranged in the condenser 86, the second part is arranged in the evaporator 87, the energy carrier in the third part flows from the evaporator 87 to the condenser 86, and the energy carrier in the fourth part flows from the condenser 86 to the evaporator 87;

[0123] The compressor 88 is disposed in the third portion of the heat exchange conduit 82;

[0124] The throttle valve 89 is provided in the fourth portion of the heat exchange pipe 82 .

[0125] During implementation, in the system loop, the cold water at the cold water coil 72 heats up after absorbing the return air heat, and the increased heat enters the evaporator 87 through the cold water circulation pipe 83 to evaporate the refrigerant. The evaporated low-temperature and low-pressure refrigerant gas enters the compressor 88 and is compressed into a high-temperature and high-pressure refrigerant gas, and then flows to the condenser 86 for condensation. During the condensation process, the refrigerant releases heat and is absorbed by the hot water circulation pipe 81. The hot water heats up and the refrigerant becomes a medium-temperature and high-pressure liquid. After flowing through the throttle valve 89, the refrigerant pressure and temperature are further reduced and become a low-temperature and low-pressure gas, and then enters the evaporator 87 to form a closed thermal cycle, and the hot water in the hot water circulation pipe 81 will flow to the hot water coil 71 to heat the air at the hot water coil 71 for drying the material. At this point, a complete multi-loop adjustable return air ratio heat pump drying system cycle is formed.

[0126] During the whole process, the first water pump 84 and the second water pump 85 are responsible for promoting the circulation of water in the system to ensure the effective transfer of heat. The air valve is used to adjust the flow path and flow rate of the air, realize the control of multiple circuits and adjustable return air ratio to adapt to different drying requirements and environmental conditions. In this way, the system can flexibly adjust the drying conditions according to the characteristics of the material and the drying requirements, and realize an efficient and energy-saving drying process.

[0127] Finally, the moisture of the material is discharged from the system to form a complete drying system. In this way, the multi-circuit adjustable return air ratio heat pump drying system can maximize energy efficiency while ensuring drying quality.

[0128] During this process, the compressor 88 increases the pressure and temperature of the refrigerant by compressing the refrigerant, and the high-temperature and high-pressure refrigerant gas flows into the condenser 86 .

[0129] The main function of the condenser 86 is to cool the high-temperature and high-pressure gas refrigerant compressed by the compressor 88 and convert it into a liquid state. In this process, the condenser 86 releases the heat in the refrigerant to the external environment (usually air or water) to achieve effective heat transfer. This process is an exothermic process. After the refrigerant is cooled in the condenser 86, it is converted from a gaseous state to a liquid state.

[0130] When the medium-temperature and high-pressure refrigerant saturated liquid flows through the throttle valve 89, it will become a low-temperature and low-pressure refrigerant liquid and produce a small amount of flash gas, thereby achieving the purpose of absorbing heat from the outside.

[0131] Inside the evaporator 87, the low-temperature and low-pressure liquid refrigerant absorbs the heat of the cold water in the cold water pipeline and evaporates into a gas, is sucked into the compressor 88 and compressed into a high-temperature and high-pressure saturated gas, then enters the condenser 86 to release heat, is condensed into a liquid again, is reduced in pressure by the throttle valve 89, and returns to the evaporator 87, forming a closed cycle.

[0132] It should be noted that there are many ways to implement the thermal cycle device. For example, a thermal cycle device using water as an energy carrier Figure 2 As shown, including:

[0133] heat exchange pipe 82, condenser 86, evaporator 87, compressor 88 and throttle valve 89;

[0134] The heat cycle device uses refrigerant as an energy carrier;

[0135] The condenser 86 is arranged at the hot water coil 71;

[0136] The evaporator 87 is arranged at the cold water coil 72;

[0137] The heat exchange pipe 82 consists of two parts, the energy carrier in the first part flows from the evaporator 87 to the condenser 86, and the energy carrier in the second part flows from the condenser 86 to the evaporator 87;

[0138] The compressor 88 is disposed in the first portion of the heat exchange conduit 82;

[0139] The throttle valve 89 is disposed in the second portion of the heat exchange pipe 82 .

[0140] Figure 2In the heat cycle device shown, the main function of the condenser 86 is to cool the high-temperature and high-pressure gas refrigerant compressed by the compressor 88 and convert it into a liquid state. In this process, the condenser 86 releases the heat in the refrigerant to the external environment (usually air or water) to achieve effective heat transfer. This process is an exothermic process. After the refrigerant is cooled in the condenser 86, it is converted from a gaseous state to a liquid state.

[0141] When the medium-temperature and high-pressure refrigerant saturated liquid flows through the throttle valve 89, it will become a low-temperature and low-pressure refrigerant liquid and produce a small amount of flash gas, thereby achieving the purpose of absorbing heat from the outside.

[0142] Inside the evaporator 87, the low-temperature and low-pressure liquid refrigerant absorbs the heat of the cold water in the cold water pipeline and evaporates into a gas, is sucked into the compressor 88 and compressed into a high-temperature and high-pressure saturated gas, then enters the condenser 86 to release heat, is condensed into a liquid again, is reduced in pressure by the throttle valve 89, and returns to the evaporator 87, forming a closed cycle.

[0143] It should be noted that both of the above-mentioned two thermal cycle devices can achieve the purpose of high efficiency and energy saving, and in specific practice, they can be selected according to needs.

[0144] Embodiment 3

[0145] It should be noted that the controller is connected to each air valve and is used to control the switch of each air valve according to the received working condition instructions to control the return air ratio in the system and the dehumidification and heating degree of the return air.

[0146] Specifically, in this embodiment, the working conditions are divided into six types:

[0147] When receiving the first operating condition instruction, the controller controls the third air valve 43 to open, and controls the first air valve 41, the second air valve 42, the fourth air valve 44, the fifth air valve 45 and the sixth air valve 46 to close, so as to control the return air ratio in the system to 100%, and all the return air is dehumidified and heated.

[0148] The gas flow direction under the first working condition is as follows Figure 3 As shown, this condition is suitable for winter. In order to maximize energy utilization, the system can completely close the introduction of ambient air and use only return air. The damper completely closes the introduction of fresh air in 100% return air mode, ensuring that all return air is dehumidified and heated.

[0149] When receiving the second operating condition instruction, the controller controls the first air valve 41, the second air valve 42 and the third air valve 43 to open, and controls the fourth air valve 44, the fifth air valve 45 and the sixth air valve 46 to close, so as to control the return air ratio in the system to 50%, and all the return air is dehumidified and heated.

[0150] The gas flow direction under the second working condition is as follows Figure 4As shown, this condition is suitable for summer, in which the system is set to a 50% return air ratio, half of the air comes from the return air of the dryer 5, and the other half comes from the external environment. All the return air is dehumidified and heated to maintain constant temperature and humidity conditions in the dryer 5.

[0151] When receiving the third operating condition instruction, the controller controls the first air valve 41, the second air valve 42, the third air valve 43, the fourth air valve 44 and the sixth air valve 46 to open, and controls the fifth air valve 45 to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and all the return air is heated.

[0152] The gas flow direction under the third working condition is as follows Figure 5 As shown, this condition is suitable for summer, in which the system is set to a 50% return air ratio, half of the air comes from the return air of the dryer 5, and the other half comes from the external environment. The return air is partially dehumidified and fully heated.

[0153] When receiving the fourth operating condition instruction, the controller controls the first air valve 41, the second air valve 42, the third air valve 43, the fourth air valve 44 and the fifth air valve 45 to open, and controls the sixth air valve 46 to close, so as to control the return air ratio in the system to 50%, all the return air is dehumidified, and part of the return air is heated.

[0154] The gas flow direction under the fourth working condition is as follows Figure 6 As shown, this condition is suitable for summer (high dew point). In this condition, the system is set to a 50% return air ratio, half of the air comes from the return air of the dryer 5, and the other half comes from the external environment. All return air is fully dehumidified and partially heated.

[0155] When receiving the fifth operating condition instruction, the controller controls the first air valve 41, the second air valve 42, the third air valve 43, the fifth air valve 45 and the sixth air valve 46 to open, and controls the fourth air valve 44 to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and part of the return air is heated.

[0156] The gas flow direction under the fifth working condition is as follows Figure 7 As shown, this condition is suitable for summer (low dew point), in which the system is set to a 50% return air ratio, half of the air comes from the return air of the dryer 5, and the other half comes from the external environment. The return air is partially dehumidified and partially heated.

[0157] When receiving the sixth operating condition instruction, the controller controls the first air valve 41 and the second air valve 42 to open, and controls the third air valve 43, the fourth air valve 44, the fifth air valve 45 and the sixth air valve 46 to close, so as to control the return air ratio in the system to 0%, all the return air is dehumidified, and all the fresh air is heated.

[0158] The gas flow direction under the sixth working condition is as follows Figure 8As shown, in this working condition, the system is set to 0% return air ratio, all the air entering the dryer 5 comes from the dry environment fresh air, all the return air is fully dehumidified and the fresh air is fully heated.

[0159] The multi-circuit adjustable return air ratio heat pump drying system in the technical solution forms multiple circuits through the first return air duct 31, the second return air duct 32 and the third return air duct 33, and sets air valves in different ducts. By controlling the switch of each air valve, the return air ratio in the system and the dehumidification and heating degree of the return air can be controlled. That is, the technical solution can adjust the return air ratio by switching each air valve according to the changes in outdoor temperature and humidity in different seasons to meet the drying needs in different situations.

[0160] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0161] It should be noted that, in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0162] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0163] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0164] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0165] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0166] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0167] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0168] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A multi-circuit adjustable return air ratio heat pump drying system, characterized in that: include: Air inlet, air outlet, heating duct, drying duct, refrigeration duct, first return air duct, second return air duct, third return air duct, first air valve, second air valve, third air valve, fourth air valve, fifth air valve, sixth air valve, dryer, fan, hot water coil, cold water coil, thermal circulation device and controller; The heating pipe comprises a first connection port, a second connection port and a third connection port; The refrigeration pipeline includes a first connection port, a second connection port and a third connection port; The first return air duct includes a first connection port, a second connection port and a third connection port; The second return air duct includes a first connection port, a second connection port and a third connection port; The third return air duct includes a first connection port and a second connection port; The first connection port of the heating duct is connected to the air inlet and the first connection port of the first return air duct, the second connection port is connected to the first connection port of the second return air duct, and the third connection port is connected to the drying duct; The first connection port of the refrigeration pipe is connected to the air outlet and the third connection port of the first return air pipe, the second connection port is connected to the third connection port of the second return air pipe, and the third connection port is connected to the drying pipe; The second connection port of the first return air duct is connected to the first connection port of the third return air duct; The second connecting port of the second return air duct is connected to the second connecting port of the third return air duct; The first air valve is arranged at the air inlet; The second air valve is arranged at the air outlet; The third air valve is arranged between the second connection port and the third connection port of the first return air duct; The fourth air valve is arranged between the first connection port and the second connection port of the third return air duct; The fifth air valve is arranged between the first connection port and the second connection port of the second return air duct; The sixth air valve is arranged between the second connecting port and the third connecting port of the second return air duct; The dryer is arranged in the drying pipeline and is used to dry the gas flowing through the dryer; The fan is arranged between the second connection port and the third connection port of the refrigeration pipeline; The thermal circulation device is connected to the hot water coil and the cold water coil; The hot water coil is arranged between the first connection port and the second connection port of the heating pipe, and is used to heat the gas in the heating pipe; The cold water coil is arranged between the first connection port and the second connection port of the refrigeration pipeline, and is used to absorb heat from the gas in the refrigeration pipeline; The controller is connected to each air valve and is used to control the switch of each air valve according to the received working condition instruction, so as to control the return air ratio in the system and the dehumidification and heating degree of the return air.

2. The multi-circuit adjustable return air ratio heat pump drying system according to claim 1 is characterized in that: The thermal cycler comprises: Hot water circulation pipeline, heat exchange pipeline, cold water circulation pipeline, first water pump, second water pump, condenser, evaporator, compressor and throttle valve; The thermal cycle device uses water as an energy carrier; The hot water coil is connected to the condenser through the hot water circulation pipeline; The first water pump is arranged in the hot water circulation pipeline; The cold water coil is connected to the evaporator through the cold water circulation pipeline; The second water pump is arranged in the cold water circulation pipeline; The heat exchange pipe is composed of four parts, the first part is arranged in the condenser, the second part is arranged in the evaporator, the energy carrier in the third part flows from the evaporator to the condenser, and the energy carrier in the fourth part flows from the condenser to the evaporator; The compressor is disposed in the third portion of the heat exchange pipe; The throttle valve is disposed in a fourth portion of the heat exchange pipe.

3. The multi-circuit adjustable return air ratio heat pump drying system according to claim 1 is characterized in that: The thermal cycler comprises: Heat exchange pipes, condensers, evaporators, compressors and throttle valves; The thermal cycle device uses a refrigerant as an energy carrier; The condenser is arranged at the hot water coil; The evaporator is arranged at the cold water coil; The heat exchange pipe is composed of two parts, the energy carrier in the first part flows from the evaporator to the condenser, and the energy carrier in the second part flows from the condenser to the evaporator; The compressor is disposed in the first portion of the heat exchange conduit; The throttle valve is disposed in the second portion of the heat exchange pipe.

4. The multi-circuit adjustable return air ratio heat pump drying system according to claim 1 is characterized in that: The third air valve is close to the third connecting port of the first return air duct; The fourth air valve is close to the second connecting port of the third return air duct; The fifth air valve is close to the second connecting port of the second return air duct; The sixth air valve is close to the second connecting port of the second return air duct.

5. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4 is characterized in that: When receiving the first working condition instruction, the controller controls the third air valve to open, and controls the first air valve, the second air valve, the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to be 100%, and all the return air is dehumidified and heated.

6. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4, characterized in that: When receiving the second working condition instruction, the controller controls the first air valve, the second air valve and the third air valve to open, and controls the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to 50%, and all the return air is dehumidified and heated.

7. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4, characterized in that: When receiving the third working condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fourth air valve and the sixth air valve to open, and controls the fifth air valve to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and all the return air is heated.

8. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4, characterized in that: When receiving the fourth working condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fourth air valve and the fifth air valve to open, and controls the sixth air valve to close, so as to control the return air ratio in the system to 50%, all the return air is dehumidified, and part of the return air is heated.

9. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4, characterized in that: When receiving the fifth working condition instruction, the controller controls the first air valve, the second air valve, the third air valve, the fifth air valve and the sixth air valve to open, and controls the fourth air valve to close, so as to control the return air ratio in the system to 50%, part of the return air is dehumidified, and part of the return air is heated.

10. The multi-circuit adjustable return air ratio heat pump drying system according to claim 4, characterized in that: When receiving the sixth operating condition instruction, the controller controls the first air valve and the second air valve to open, and controls the third air valve, the fourth air valve, the fifth air valve and the sixth air valve to close, so as to control the return air ratio in the system to 0%, all the return air is dehumidified, and all the fresh air is heated.

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