CN116007308A

CN116007308A - Solar heat pump drying system with high-low temperature energy supplementing and dehumidifying functions

Info

Publication number: CN116007308A
Application number: CN202210317820.8A
Authority: CN
Inventors: 李明; 张祖德; 李国良
Original assignee: Yunnan Normal University
Current assignee: Yunnan Normal University
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2023-04-25

Abstract

The invention discloses a solar heat pump drying system with high and low temperature energy supplementing and dehumidifying functions, which adopts a solar heat collecting and energy storing system, a glycol antifreeze high and low temperature energy supplementing system and a drying system combining an air source heat pump system and a dehumidifying system. In order to alleviate the problem of low heating efficiency of the air source heat pump in a low-temperature environment, a solar heat collection and energy storage system is utilized to store heat in a form of heating water; when the air temperature is low, the stored heat is released to the glycol antifreeze fluid graded heat exchange energy supplementing system in the form of hot water to carry out energy supplementing with different temperature gradients, so that the efficiency of the drying system is improved; meanwhile, a polymer dehumidification system is started, so that the humidity in the drying box is effectively controlled, the drying quality of materials is ensured, and the drying time is shortened. The solar energy, air energy and electric energy are complemented with each other in multiple energy, heat is effectively saved by supplementing energy at high and low temperatures, the system is maintained to run stably, the material drying period is obviously shortened, the environmental pollution is reduced, and the comprehensive energy utilization efficiency and the economic efficiency are improved.

Description

Solar heat pump drying system with high-low temperature energy supplementing and dehumidifying functions

Technical Field

The invention relates to a drying system, in particular to a double-evaporator serial air source heat pump drying system with solar energy storage, high-low temperature energy supplement and dehumidification, and belongs to the technical field of new energy drying.

Background

Solar energy and air energy are environment-friendly low-level energy, and are very suitable for coastal islands, grassland pasture areas, mountain areas and plateau areas which are lack of water, fuel and inconvenient in transportation, and the energy sources are utilized according to local conditions. At present, when the conventional air source heat pump is used in a region with high temperature difference between a plateau, severe cold and day and night, the heat pump unit can work normally when the ambient temperature is higher, and when the ambient temperature is reduced to below 0 ℃, the heating performance of the unit fluctuates and decays, the temperature of a drying room is obviously reduced, the humidity is higher, the drying operation is not utilized, the frosting condition of an evaporator can occur when the ambient temperature is continuously reduced to the dew point temperature of air, the compression ratio of a compressor is increased, and the exhaust temperature of the compressor is rapidly increased to cause the alarm shutdown of the system. There is a limit to using either solar energy or air source heat pump alone to dry, and for this purpose, it is still an urgent situation to combine the two, with complementary advantages to achieve stable and continuous drying.

With the development of society and the development of economy, drying is mainly used as constant temperature drying and heating equipment for foods, dairy products, meats, aquatic products, chemical industry, medicines and the like, and a drying system has played a bigger and bigger role in the fields of industry, agriculture, bio-pharmaceuticals and the like. The traditional drying method generally adopts an open air natural drying method, which has a plurality of defects: the efficiency is low, the occupied area is large, the time and the labor are consumed, the influence of weather conditions such as gust, plum rain and the like is easy, the pollution of wind sand, dust, insect and ant and the like is easy, and the quality of dry food or agricultural and sideline products is difficult to ensure. The artificial drying industry is an industry with larger energy consumption, depends on heat provided by fossil fuel, has serious environmental pollution on one hand, and on the other hand, has difficulty in ensuring the quality of dried food or agricultural and sideline products, and is easy to cause secondary pollution. At present, the energy crisis and the environment crisis, from the energy conservation perspective or from the environment protection perspective, the new energy is actively developed, the heat energy utilization rate is improved, and the method is a necessary trend of the development of the green drying industry.

Disclosure of Invention

Aiming at the defects in the drying mode, the invention provides a solar heat pump drying system with high and low temperature energy supplementing and dehumidifying functions for reducing the energy consumption and low efficiency of the existing drying system at low temperature. The heat is utilized in a grading way by grading energy storage solar heat and energy supplementing, so that the heat grading utilization is realized, the heat and heat exchange rate of working media are improved, the problems of attenuation fluctuation and low efficiency of the heating performance of the heat pump under the working conditions of high altitude, severe cold and large temperature difference are effectively controlled, the drying rate of the drying box is stabilized, the universality of the system is improved, the energy is effectively saved, and the drying efficiency is improved.

In order to achieve the above purpose, the technical scheme of the invention is as follows: the system is composed of a solar heat collection energy storage system, an ethylene glycol antifreeze high-low temperature energy supplementing system, an air source heat pump system and a dehumidification system.

The ethylene glycol antifreeze high-low temperature energy supplementing system consists of a high-low temperature energy storage water tank, is connected with a solar heat collector and stores energy in a grading manner; the high-low temperature energy supplementing is to select a water tank with proper temperature after monitoring the heat exchange rate of the system and converting the heat exchange rate into the corresponding required temperature; and after the energy is supplemented, the water tank or the heat collector with the corresponding temperature can be selected according to the temperature.

The specific form of the high-low temperature energy supplementing is as follows: the temperature of the drying box is monitored, the temperature detector is fed back, the electromagnetic valve behind the high-temperature heat exchange water tank or the low-temperature water tank is selected to be opened, the temperature monitor of the water supply pump and the electromagnetic valve or the opening of the electromagnetic valve are fed back in time, the stable state of the heat of the selected heat exchange water tank is guaranteed, the glycol antifreeze with proper temperature is conveyed to the plate heat exchanger, the plate heat exchanger and the evaporator are connected in series, the working medium is heated in the evaporator once and then is fed to the compressor after being heated in the plate heat exchanger again, so that the heat of the working medium is improved, the heat exchange rate is improved, and the problems of attenuation fluctuation and low efficiency of the heat pump heating performance under the working conditions of high altitude, severe cold and large temperature difference and the drying rate of the stable drying box can be solved.

The solar heat collection and energy storage system is connected with the air source heat pump system in series through a heat pump energy supplementing system in a mode of connecting a plate heat exchanger with an air source heat pump evaporator,

furthermore, the dehumidification system is a box body which is arranged in the drying box and can be pulled and replaced, and dehumidification materials are uniformly distributed in the box body.

Further, the solar heat collection and energy storage system comprises a vacuum tube heat collector, a heat storage water tank, a circulating water pump and a temperature difference controller, and the circulating water pump is controlled to exchange heat in the heat storage water tank into the pressure-bearing water tank by monitoring the temperature of the pressure-bearing heat exchange water tank.

Further, the solar vacuum tube is arranged on the inclined foundation frame and provided with a wire opening for ground fixation.

Further, the interior of the drying box is divided into a circulating return air duct, and an axial flow return air fan is arranged at the air duct opening.

Further, the electromagnetic valve connected with the dehumidifying evaporator in the drying oven is in a normally open state.

Further, the drying box structure is a cuboid structure, and 9 circulating air mechanisms are arranged in the box body to form an air wall.

Further, the material rack and the material tray in the drying box are separated, and universal wheels are arranged at the bottom of the material rack.

The invention has the advantages and beneficial effects that: the method utilizes the energy-saving classified heat storage and the classified energy compensation, adopts the replaceable and reusable adsorption material to the humidity in the drying box, stores hot water to heat the rear end of the evaporator through the high-temperature and low-temperature water tank, realizes the secondary heating of the refrigerant, solves the problems of attenuation fluctuation and low efficiency of the heat pump heating performance of the air source heat pump under the working conditions of high altitude, severe cold and large temperature difference, stabilizes the drying rate of the drying box, and is an ideal drying system. .

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the following second are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a solar heat pump drying system with high and low temperature energy supplementing and dehumidification according to the present invention.

Fig. 2 is a diagram of a high-low temperature energy supplementing system provided by the invention.

In the figure: 1. a solar collector; 2. a heat collecting circulating water pump; 3. a temperature difference controller; 4. a heat storage water pump; 5. a temperature difference controller; 6. an electromagnetic valve; 7. an electromagnetic valve; 8. a high temperature heat storage water tank; 9. electric heating of the high-temperature heat storage water tank; 10. an electromagnetic valve; 11. an electromagnetic valve; 12. a temperature difference controller; 13. a low temperature heat storage water tank; 14. an electromagnetic valve; 15. an electromagnetic valve; 16. electric heating of the low-temperature heat storage water tank; 17. an electromagnetic valve; 18. a temperature difference controller; 19. an energy supplementing evaporator; 20. an electromagnetic valve; 21. a compressor; 22. a condenser; 23. a condenser fan; 24. a throttle valve; 25. an evaporator; 26. an evaporator fan; 27. a return air blower; 28. a drying box; 29. a material rack; 30. a drain hole; 31. a detachable frame; 32. a lithium chloride-silica gel layer; 33. a dehumidifying evaporator.

Detailed Description

The invention is described in further detail below with reference to the drawings and examples.

The invention provides a solar heat pump drying system for high-low temperature energy supplementing and dehumidification.

As shown in figure 1, the high and cold region heat pump drying system with solar energy and rotating wheel dehumidification and grading energy supplementing comprises a rotating wheel dehumidification energy supplementing system, a solar heat collector and an air source heat pump system, wherein the drying system comprises drying box internal circulation and adsorption material analysis.

Firstly, the solar heat collector 1 is fixedly installed in the open and non-shielding area towards the south, the outlet of the heat collector 1 is connected with the high-temperature heat storage water tank 8, then the inlet of the heat collector 1 is connected with the lower part of the low-temperature heat storage water tank 13 and the circulating pump 2 is installed in the middle of the low-temperature heat storage water tank 13, the temperature of the outlet of the heat collector is monitored by the temperature difference controller 3 through a temperature sensor, and the start and stop of the circulating pump 2 are controlled through the temperature difference.

And secondly, the drying system dynamically supplements energy by monitoring the ambient temperature, the humidity and the heat exchange quantity of the air source heat pump, and the temperature change is monitored by the temperature difference controllers 3 and 5 to regulate and select the operation of the energy supplementing system and the opening degree of the electromagnetic valve 7 or 6 to control the energy supplementing quantity.

Then, the corresponding energy supplementing water tank is selected for energy supplementing, the plate type evaporator 19 for energy supplementing is connected with the evaporator 25 in the air source heat pump drying system in parallel, the dehumidifying evaporator 33 is connected with the rear end of the energy supplementing plate type evaporator 19 and the front end of the evaporator 25 through the electromagnetic valve 20, the opening of the electromagnetic valve 20 is half-opened at maximum, and the circulation direction of the refrigerant and the circulation direction of the energy supplementing hot water are opposite.

Finally, the high-temperature humid air in the drying box 28 is absorbed by the lithium chloride-silica gel composite material on the lithium chloride-silica gel layer 32 to evaporate by the return air fan 27, then is subjected to heat exchange on the dehumidifying evaporator 33, the working medium in the dehumidifying evaporator 33 absorbs heat, and meanwhile, the humid air is condensed into water and is discharged through the drain hole 30, and the heated working medium is sent to the front end of the evaporator 25, so that the heat exchange mass flow is improved. Thus, the solar auxiliary air source heat pump drying system based on the phase change material rotating wheel dehumidification energy supplementing under the large temperature difference is completed.

Specifically, during daytime, solar energy is sufficient, irradiation intensity is sufficient, when the environment is stable and is not lower than 5 ℃, an air source heat pump system is utilized to drive a compressor 21 in a drying system to work, heat is released to a drying box through a fan 23 at a condenser 22 to heat up and dry, meanwhile, a solar heat collection storage system is used for storing energy, the heat collector 1 absorbs solar energy to heat water of a high-temperature heat storage water tank 8 and a low-temperature heat storage water tank 13, water circulation is carried out through circulating water pumps 2 and 4 of the heat collection storage system, meanwhile, temperature change is monitored by using temperature difference controllers 3 and 5, solar photovoltaic is guaranteed to absorb solar energy during daytime and is converted into hot water to be stored in a storage tank, and enough heat is stored for use at night and under low temperature. At night, the solar energy cannot be absorbed by the heat collector 1, the circulating water pumps 2 and 4 of the heat collection and storage system are closed, and the energy storage system stops energy storage. At this ambient temperature, when the drying system is in steady operation, the air source heat pump system is always used for the drying operation of the whole drying system.

Specifically, in the cloudy weather or in the environment with larger temperature difference at night, solar irradiation is insufficient in daytime, when the irradiation is good, according to the condition of solar irradiance intensity, when the ambient temperature is higher than 5 ℃, the compressor 21 of the air source heat pump drying system is driven to work, when the heat exchange capacity of the evaporator 25 of the air source heat pump drying system is monitored to be reduced and the ambient temperature is lower than 5 ℃, the high-temperature and low-temperature energy supplementing system is monitored to work, the amount of the supplemented energy and the temperature are regulated and controlled through the heat exchange capacity signal of the temperature detector 18, the electromagnetic valve 10 or 15 in front of the high-temperature heat storage water tank 8 or the low-temperature heat storage water tank 13 is selected to be opened, stored hot water is transmitted to the energy supplementing plate heat exchanger 19, the stored heat is utilized to the maximum extent, meanwhile, the plate heat exchanger 19 is prevented from being damaged due to overheat after the water is directly connected into the plate heat exchanger, backwater is returned to the water tank or the heat collector 1 according to the temperature difference controller 12, and the circulation is a complete energy supplementing circulation; the problems of attenuation fluctuation and lower efficiency of the drying system in cloudy weather and heat pump heating performance are guaranteed, the drying rate of the drying box is stabilized, and the temperature of the drying box is always at a set temperature.

Specifically, in rainy and snowy days, under the condition that solar energy is insufficient in daytime and irradiance is extremely small, when the air source heat pump system cannot stably operate, and in the condition, the frosting phenomenon of the evaporator 25 can occur, so that the heat exchange efficiency of the evaporator is greatly reduced, at the moment, the normal operation of the air source heat pump is maintained, meanwhile, the temperature difference controller 18 receives a signal, the high-temperature heat storage water tank 8 or the low-temperature heat storage water tank 13 is selected according to calculation to supplement energy to the plate-type energy supplementing heat exchanger 19 through monitoring the temperature of the drying box 28, the corresponding electromagnetic valve 10 or 15 is started, and when continuous rainy days are caused, the electric heating 9 or 16 in the water tank can be started, the corresponding temperature range of the water tank for energy supplementing is heated, and the energy supplementing effect and the heat utilization rate are ensured; the temperature of the drying box is kept at the set temperature through the grading energy supplementing system, so that the problems of attenuation fluctuation and low efficiency of the heating performance of the heat pump under the working conditions of high altitude, severe cold and large temperature difference are solved, and the drying rate of the drying box is stabilized.

The present invention is not limited to the preferred embodiments, which are disclosed above, but rather, the present invention is not limited to the preferred embodiments, and any person skilled in the art can make a few changes or modifications to the equivalent embodiments without departing from the technical scope of the present invention, but any simple modification, equivalent changes and modifications to the above embodiments according to the technical principles of the present invention are still within the scope of the technical scheme of the present invention.

Claims

1. A solar heat pump drying system with high-low temperature energy supplementing and dehumidifying functions is characterized by adopting a solar heat collecting and energy storing system, a glycol antifreeze high-low temperature energy supplementing system, an air source heat pump system and a dehumidifying system.

2. The high-low temperature energy supplementing system of the ethylene glycol antifreeze fluid is divided into: when the required energy supplementing heat is 25-35 ℃, the heat in the low-temperature barrel is adopted for energy supplementing, and when the required energy supplementing heat is 35 ℃ or above, the heat in the high-temperature barrel is adopted for energy supplementing.

3. The problem that the heat exchange efficiency is reduced due to the fact that the evaporator frosts in the air source heat pump under the low-temperature environment is solved, meanwhile, the maximum utilization of stored heat can be achieved by utilizing high-low temperature interaction energy supplement, the optimal running condition of the drying system is maintained, and the drying efficiency and the energy supplement system utilization rate are improved.

4. The glycol antifreeze high-low temperature energy supplementing system of claim 1, wherein the system comprises a high-temperature heat exchange water tank, a low-temperature heat exchange water tank, a heat exchange coil, an electric heater, a circulating water pump, a plate heat exchanger, a PVC pipeline, a temperature monitor, an electromagnetic valve and the like, wherein the heat exchange coil is vertically arranged in the heat exchange water tank, the heat exchange coil is connected with the heat storage water tank through a pipeline, and auxiliary electric heating equipment is arranged in the middle of the heat exchange water tank.

5. The plate-type evaporator for energy supplementing is connected in series with the evaporator of the air source heat pump, the plate-type heat exchanger is connected with the glycol antifreeze in the heat exchange water tank, the glycol antifreeze heat exchange water tank is added for secondary heat exchange, the temperature of glycol entering the plate-type energy supplementing heat exchanger can be controlled, and meanwhile, the damage of the plate-type heat exchanger caused by freezing after water is directly connected into the plate-type heat exchanger is prevented; when the temperature fluctuation in the drying box is detected and the heat exchange quantity is reduced, the grading energy supplementing system is started, the system calculates according to the drying set value and the current system operation working condition requirement, the model is transmitted to a temperature monitor and an electromagnetic regulating valve at the rear end of the heat exchange water tank, the selection of the high-temperature or low-temperature heat exchange water tank is regulated, and the proper temperature energy supplementing working quantity is carried out, so that the whole drying system is ensured to be stably in the set working condition.

6. The solar heat collection and energy storage system of claim 1, wherein a vacuum tube heat collector is adopted and installed towards the south, the installation inclination angle is the installation ground dimension, a temperature probe is installed between the heat storage water tank and the heat collector to collect temperature signals, and a temperature difference controller and a circulating water pump are installed between the heat storage water tank and the heat collector to ensure the stability of heat storage.

7. The drying system of claim 1, wherein a detachable frame of uniformly distributed lithium chloride-silica gel composite material, a dehumidifying evaporator and a return air blower are arranged at a return air passage of the drying box, and the dehumidifying evaporator is connected with the energy compensating evaporator and the evaporator; the wet air in the drying box is blown onto the lithium chloride-silica gel composite material on the detachable frame of the return air channel and the dehumidifying evaporator through the action of the return air fan, the lithium chloride-silica gel composite material and the dehumidifying on the frame absorb the water vapor in the drying box respectively, the lithium chloride-silica gel composite material absorbs water and saturates into crystals, the dehumidifying evaporator absorbs heat by working media to condense out water, the humidity is reduced, the water is blown into the drying box again, the saturated crystals are replaced by the detachable frame, and the condensed water is discharged through the drain hole; the dehumidifying system collects a large amount of heat while dehumidifying, improves the drying efficiency, saves the energy consumption and reduces the drying time.

8. The dehumidifying evaporator of claim 1 is located in a drying cabinet, the amount of refrigerant entering is controlled by a solenoid valve at the back end of energy supplementing evaporation, and the heat is absorbed in the drying cabinet and the wet air is condensed, and at the same time, the heated refrigerant is sent to the front end of the evaporator, so that the heat exchange capacity of the evaporator is improved, and the overall system efficiency is improved.