Air energy heating and drying equipment with double heat recovery

Abstract

This utility model discloses an air-source heat pump drying device with dual heat recovery, belonging to the field of drying technology. It includes an air-source heat pump main unit and a drying oven. The air-source heat pump main unit includes a frame and a heat exchanger, a draft fan, a heat pump, a liquid receiver, an expansion valve, a drying filter, a finned evaporator, and an electric heater mounted on the frame. The heat exchanger, draft fan, and electric heater form a heating chamber via the frame and partitions. A heat exchange core is installed at the connection between the upper part of the drying oven and the heating chamber. The heat exchange core is composed of intersecting air ducts arranged at intervals. The longitudinal air ducts form the air inlet pipe of the air-source heat pump main unit, connecting to the heating chamber, while the transverse air ducts form the air outlet pipe, connecting to the exhaust pipe of the finned evaporator. This utility model achieves dual heat recovery through the heat exchange core and the finned evaporator, overcoming the limitations imposed by the working principle of air-source heat pumps while ensuring energy conservation, thus improving product applicability.

Description

Technical Field

[0001] This utility model relates to the field of air source heat pump drying technology, and more specifically, to an air source heat pump heating and drying device with dual heat recovery. Background Technology

[0002] Our utility model patent, "A Cascade Air Source Heat Pump Heating Unit and Drying Equipment and Its Application" (application number CN202211311546.X), discloses a cascade air source heat pump heating unit. This unit employs a main heat exchanger and a secondary heat exchanger for dual heating, achieving efficient waste heat recovery and good energy-saving results. The equipment uses a secondary heat exchanger to preheat the outside air entering the main heating chamber. Most of the high-temperature, high-humidity waste gas in the dryer passes through a finned evaporator before entering the main heating chamber for recycling. While this saves electricity, the condenser temperature of the air source heat pump heating system itself is limited to below 100℃ in high-temperature environments. If the electric heater raises the temperature inside the drying oven above 100℃, the air source heating system will not function properly, limiting its use for drying certain agricultural products. The significance of this utility model lies in solving this problem. While ensuring energy conservation, it removes the limitations imposed by the working principle of air source heat pumps, improving the practicality and applicability of the product. Summary of the Invention

[0003] In view of the problems existing in the prior art, the purpose of this utility model is to solve the problem of waste heat and waste gas in the drying room and to make comprehensive utilization, so as to provide an energy-saving and efficient material drying equipment.

[0004] To solve the above problems, this utility model adopts the following technical solution: a dual heat recovery air source heating and drying device, including an air source heating main unit and drying ovens disposed on one or both sides of the air source heating main unit. The air source heating main unit includes a frame and a heat exchanger, a duct fan, a heat pump, a liquid receiver, an expansion valve, a drying filter, a finned evaporator, and an electric heater disposed on the frame. The finned evaporator is disposed in an exhaust duct located above the air source heating main unit, the heat exchanger is located above the electric heater, and the duct fan is installed on the heat exchanger. On the lower surface with the airflow direction from top to bottom, the heat exchanger, the induced draft fan, and the electric heater form a heating chamber through a frame and partition. A heat exchange core is installed at the connection between the upper part of the oven and the heating chamber. The heat exchange core is composed of intersecting air ducts arranged at intervals. The longitudinal air ducts form the air intake pipe of the air-source heating host and connect to the heating chamber, while the transverse air ducts form the air outlet pipe and connect to the exhaust pipe where the finned evaporator is located. The air ducts are made of thermally conductive metal material. A liquid collection tank is provided below the finned evaporator and the heat exchange core. The liquid collection tank is discharged outside the drying equipment through a drain pipe.

[0005] Furthermore, the heat exchange core is provided with a return line inside the air duct.

[0006] Furthermore, the duct is equipped with multiple heat-conducting toothed racks aligned with the direction of the duct's airflow.

[0007] Furthermore, a guide plate is provided at the bottom of the heating host below the electric heater.

[0008] Furthermore, an exhaust fan is installed inside the exhaust duct.

[0009] Furthermore, the drain pipe is connected to a condensate tank located outside the oven.

[0010] Compared with the prior art, this utility model has the following advantages:

[0011] (1) During the material drying process, the heat exchange core is designed to use the high-temperature exhaust gas discharged from the oven to heat the outside air entering the heating chamber of the dryer in the first stage, so as to achieve the first stage of heat recovery. Here, the heat exchange core will generate a small amount of high-temperature moisture that condenses upon cooling to form condensate. This part of the condensate is collected in the condensate tank.

[0012] (2) During the material drying process, the low-temperature finned evaporator of the air-source heating host absorbs heat again from the high-temperature and high-humidity exhaust gas discharged from the heat exchange core, and the heat recovered by this part is transferred to the heat exchanger through the air-source system to heat the air entering the heating chamber for a second time. In this way, the finned evaporator achieves a second heat recovery. The low-temperature finned evaporator will condense a large amount of condensate, which is collected in the condensate tank.

[0013] (3) Compared with the previous generation of cascade air-source heat pump ovens of our company, this dryer has the advantage of unlimited heating temperature. Through two heat recovery stages, heat recovery of 60-90% is achieved (the higher the drying temperature of the oven, the lower the heat recovery ratio). All the high-temperature and high-humidity exhaust gas in the oven is discharged from the dryer. The temperature of the air entering the air-source heat exchanger after the initial heating of the heat exchange core will not affect the normal operation of the air-source system. After the second heating stage of the air-source heat exchanger to below 100℃, it is heated to 100℃-150℃ or even higher by the electric heater below. This provides the dryer with practicality and applicability. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the utility model;

[0015] Figure 2 This is a schematic diagram of the heat exchange core structure of the utility model;

[0016] Figure 3This is a schematic diagram of a utility model duct structure;

[0017] Figure 4 This is a structural schematic diagram of the air duct routing of the utility model;

[0018] Figure 5 This is a schematic diagram of the structure of a utility model double-sided drying oven. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model; Example

[0020] like Figure 1-5 As shown, an air-source heat pump drying device with dual heat recovery includes an air-source heat pump main unit 1 and drying ovens 2 disposed on one or both sides of the air-source heat pump main unit 1. The air-source heat pump main unit 1 includes a frame 1 and a heat exchanger 12, a duct fan 13, a heat pump 14, a liquid receiver 15, an expansion valve 16, a drying filter 17, a finned evaporator 18, and an electric heater 19 disposed on the frame 11. The finned evaporator 18 is disposed in an exhaust duct 3 located above the air-source heat pump main unit 1, and the heat exchanger 12 is located in an electric heater... Above the heat exchanger 19, a duct fan 13 is installed on the lower surface of the heat exchanger 13 with the airflow direction from top to bottom (the duct fan can also be placed on the upper surface of the heat exchanger). The heat exchanger 12, the duct fan 13, and the electric heater 19 form a heating chamber 4 through a frame 11 and a partition 10. A heat exchange core 5 is provided at the connection between the upper part of the oven 2 and the heating chamber 4. The heat exchange core 5 is composed of intersecting air ducts 51 arranged at intervals. The longitudinal air ducts 51 form the air intake pipe 511 of the air source heating unit 1, which is connected to the heating chamber 4. Figure 2 (The shaded area indicates a closed section, and the white area indicates a through section). The horizontal air duct 51 forms the air outlet duct 512, which is connected to the exhaust duct 3 where the finned evaporator 18 is located. The air duct 51 is made of thermally conductive metal material. The finned evaporator 18 and the heat exchange core 5 are provided with a liquid collection tank 7 below them. The liquid collection tank 7 is discharged outside the drying equipment through a drain pipe.

[0021] The air source heating system and other technologies in this equipment can refer to the relevant content of our company's utility model patent, "A Cascade Air Source Heating Main Unit and Drying Equipment and Its Application" (Patent No. ZL202211311546.X). Based on this utility model patent, the auxiliary heat exchanger is removed, and copper pipes are used to sequentially connect the heat pump 14, heat exchanger 12, dryer filter 17, liquid receiver 15, expansion valve 16, and finned evaporator 18, and then connect them back to the heat pump 14 to form a loop. The heating air duct is redesigned so that all high-temperature and high-humidity exhaust gas is discharged from the drying equipment after heat recovery and moisture recovery, and fresh air from the outside is fully replenished into the drying equipment. This overcomes the problem of limited operation of the air source heating system caused by the circulation of high-temperature exhaust gas in the drying equipment and only the replenishment of a small amount of fresh air in the original patent technology.

[0022] like Figure 4 As shown, the air duct design of the single-sided drying oven 2 in this application is as follows: fresh air from the outside enters the heating chamber 4 through the air intake pipe 511 of the heat exchange core 5 via the induced draft fan 13 in the heating chamber 4 and flows from top to bottom through the drying oven 2. The air duct in the drying oven flows from bottom to top, and then enters the exhaust pipe 3 of the drying equipment through the exhaust pipe 512 of the heat exchange core. After passing through the finned evaporator 18 in the exhaust pipe 3, it is discharged from the drying equipment.

[0023] The air duct design of the double-sided drying oven in this application refers to the single-sided design described above, with two heat exchange cores, finned evaporators, and exhaust ducts symmetrically arranged (the two sets of exhaust ducts can be combined into one, and the finned evaporator can be placed inside the main exhaust duct). They can be symmetrically arranged above the heating unit. The heat pump, drying filter, liquid receiver, expansion valve, etc. of the air source heating unit 1 can be adjusted and arranged at the rear of the entire dryer, outside the rear side wall of the heating chamber.

[0024] A flow line is installed inside the air duct 51 of the heat exchange core 5, which can cause the airflow to rotate and turbulent as it passes through the air duct, thereby improving the heat exchange efficiency.

[0025] like Figure 3 As shown, instead of using a rifling wire inside the duct 51, a heat-conducting rack 513 can be used. Multiple heat-conducting racks aligned with the duct's airflow direction are installed inside the duct. These heat-conducting racks can significantly increase the thermal contact area and improve heat exchange efficiency.

[0026] The bottom of the heating unit below the electric heater 19 is provided with a guide plate 6. The guide plate can straighten the airflow and reduce the turbulence caused by hot air impacting the bottom plate of the heating chamber. Furthermore, baffles 61 can be evenly arranged on the guide plate. After the airflow passes through the baffles and straightens, it changes direction and enters the oven evenly.

[0027] An exhaust fan 31 is installed inside the exhaust duct 3. The exhaust fan provides power for exhaust, reducing the load on the induced draft fan.

[0028] The drain pipe is connected to a condensate tank 21 located outside the oven 2. The condensate is collected; for example, when drying rose petals, rose essential oil and other byproducts can be extracted from the condensate, increasing the added value of agricultural products.

[0029] The above description is merely a preferred embodiment of this utility model; however, the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and its improved concept, should be included within the protection scope of this utility model.

Claims

1. An air-source heat pump drying device with dual heat recovery, characterized in that: The equipment includes an air-source heat pump main unit and an oven disposed on one or both sides of the main unit. The main unit includes a frame and a heat exchanger, a duct fan, a heat pump, a liquid receiver, an expansion valve, a drying filter, a finned evaporator, and an electric heater mounted on the frame. The finned evaporator is disposed in an exhaust duct located above the main unit. The heat exchanger is located above the electric heater. The duct fan is installed on the lower surface of the heat exchanger with the airflow direction from top to bottom. The heat exchanger, duct fan, and electric heater form a heating chamber through the frame and partition. A heat exchange core is disposed at the connection between the upper part of the oven and the heating chamber. The heat exchange core is composed of intersecting air ducts arranged at intervals. The longitudinal air ducts form the air inlet pipe of the main unit and connect to the heating chamber, while the transverse air ducts form the air outlet pipe and connect to the exhaust duct where the finned evaporator is located. The air ducts are made of thermally conductive metal material. A liquid collection tank is disposed below the finned evaporator and the heat exchange core. The liquid collection tank discharges the liquid outside the drying equipment through a drain pipe.

2. The air-source heat pump drying equipment with dual heat recovery as described in claim 1, characterized in that: The heat exchange core is equipped with a return line inside the air duct.

3. The air-source heat pump drying equipment with dual heat recovery as described in claim 1, characterized in that: The duct is equipped with multiple heat-conducting toothed racks aligned with the direction of the duct's airflow.

4. The air-source heat pump drying equipment with dual heat recovery as described in claim 1, characterized in that: A guide plate is provided at the bottom of the heating unit below the electric heater.

5. The air-source heat pump drying equipment with dual heat recovery as described in claim 1, characterized in that: An exhaust fan is installed inside the exhaust duct.

6. The air-source heat pump drying equipment with dual heat recovery as described in claim 1, characterized in that: The drain pipe is connected to a condensate tank located outside the oven.

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