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

Abstract

The invention discloses a solar heat pump drying system with high and low temperature energy replenishment and dehumidification, which adopts a solar heat collection energy storage system, an ethylene glycol antifreeze high and low temperature energy replenishment system, an air source heat pump system and a dehumidification system combined drying system. In order to alleviate the problem of low heating efficiency of air source heat pumps in low temperature environments, the solar thermal energy storage system is used to store heat in the form of heated water; when the temperature is low, the stored heat is released to ethylene glycol in the form of hot water for antifreeze The liquid graded heat exchange energy replenishment system performs different temperature gradient energy replenishment to improve the efficiency of the drying system; at the same time, the polymer dehumidification system is activated to effectively control the humidity in the drying box to ensure the drying quality of the material and reduce the drying time. Realize the multi-energy complementarity of solar energy, air energy, and electric energy. High and low temperature supplementation can effectively save heat, maintain stable system operation, significantly shorten the drying cycle of materials, reduce environmental pollution, and improve comprehensive energy utilization efficiency and economic efficiency.

Description

A solar heat pump drying system with high and low temperature energy replenishment and dehumidification

technical field

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

Background technique

Solar energy and air energy are environmentally friendly low-level energy sources, and are very suitable for using these energy sources according to local conditions for coastal islands, grassland pastoral areas, mountainous areas, and plateau areas that lack water, fuel, and inconvenient transportation. At present, when conventional air source heat pump drying works in plateau, severe cold, and areas with large temperature difference between day and night, the heat pump unit can work normally when the ambient temperature is high, but when the ambient temperature drops below 0°C, the heating performance of the unit fluctuates and Attenuation, the temperature of the drying room is significantly lower and the humidity is higher. If the drying operation is not used, when the ambient temperature continues to drop to the dew point temperature of the air, the evaporator will frost, the compression ratio of the compressor will increase, and the discharge temperature of the compressor will increase sharply. The rise causes the system to alarm and shut down. There are certain limitations in using a certain form of solar energy or air source heat pump alone for drying. Therefore, it is imminent to combine the two and complement each other to achieve stable and continuous drying.

With the progress of society and the development of economy, drying is mainly used as constant temperature drying and heating equipment for food, dairy products, meat, aquatic products, chemicals, medicine, etc. The drying system has played an increasingly important role in the fields of industry, agriculture, and biopharmaceuticals. Covenant big role. Traditional drying usually adopts the open-air natural drying method, which has many disadvantages: low efficiency, large footprint, time-consuming and labor-intensive, easily affected by climatic conditions such as showers and plum rains, and also vulnerable to wind, sand, dust, insects and ants, etc. Pollution, it is difficult to guarantee the quality of dry food or agricultural by-products. The artificial drying industry is an industry that consumes a lot of energy. It relies on the heat provided by fossil fuels. On the one hand, it pollutes the environment seriously. On the other hand, it is difficult to guarantee the quality of dried food or agricultural by-products, which is easy to cause secondary pollution. In today's energy crisis and environmental crisis, it is an inevitable trend for the development of the green drying industry to actively develop new energy and improve the utilization rate of heat energy, no matter from the perspective of energy saving or environmental protection.

Contents of the invention

In order to reduce the energy consumption and low efficiency of the existing drying system at low temperature, the present invention provides a solar heat pump drying system with high and low temperature energy replenishment and dehumidification, aiming at the shortcomings in the above drying methods. By graded energy storage of solar heat and using it for supplementary energy, the graded utilization of heat is realized, the heat of the working fluid is improved, the heat transfer rate is effectively controlled, and the attenuation and fluctuation of heat pump heating performance and low efficiency are effectively controlled under the conditions of plateau, severe cold, and large temperature difference. problems and stabilize the drying rate of the drying oven, increase the universality of the system, effectively save energy and improve drying efficiency.

In order to achieve the above object, the technical solution of the present invention is: a solar thermal energy storage system, an ethylene glycol antifreeze high and low temperature energy supplement system, an air source heat pump system and a dehumidification system.

The high and low temperature energy replenishment system for ethylene glycol antifreeze consists of high and low temperature energy storage tanks, which are connected to solar collectors and store energy in stages; the high and low temperature energy replenishment is converted into After corresponding to the required temperature, select a water tank with an appropriate temperature; for the high and low temperature replenishment described above, after the replenishment is completed, the return water will select a water tank or heat collector corresponding to the temperature according to the temperature.

The specific form of the high and low temperature replenishment is: by monitoring the temperature of the drying box, feeding back to the temperature detector and selecting the opening of the solenoid valve behind the high-temperature water exchange tank or low-temperature water tank, and timely feeding back to the water pump temperature monitor and solenoid valve or open, to ensure the heat stability of the selected heat exchange tank, and to transport the suitable temperature of ethylene glycol antifreeze to the plate heat exchanger. After one internal heating, the energy is supplemented in the plate heat exchanger and then sent to the compressor to increase the heat of the working medium and improve the heat transfer rate, which can solve the heating performance of the heat pump under the conditions of plateau, severe cold, and large temperature difference Attenuation fluctuations, issues with lower efficiency and drying rates in stable ovens.

The solar thermal energy storage system and the air source heat pump system are connected through a heat pump energy supplement system in the form of a plate heat exchanger connected in series with the air source heat pump evaporator,

Further, the dehumidification system is a drawable and replaceable box placed in a drying box, and dehumidification materials are evenly distributed in the box.

Further, the solar heat collection and energy storage system includes a vacuum tube heat collector, a hot water storage tank, a circulating water pump and a temperature difference controller. The heat is exchanged to the pressurized water tank.

Further, the solar vacuum tube is installed on an inclined foundation frame, and a thread opening is provided for fixing on the ground.

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

Further, the solenoid valve connected to the dehumidification evaporator in the drying box is normally open.

Further, the structure of the drying box is a cuboid structure, and 9 circulating fans are arranged in the box to form a wind wall.

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

The advantages and beneficial effects of the present invention are: use solar energy to store heat in stages, replenish energy in stages, and at the same time adopt replaceable and reusable adsorption materials for the humidity in the drying box, and store hot water to evaporate heat through high-temperature and low-temperature water tanks The rear end of the device realizes the secondary heating of the refrigerant, which solves the problem of attenuation and fluctuation of heat pump heating performance and low efficiency of the air source heat pump under the conditions of plateau, severe cold, and large temperature difference, and stabilizes the drying rate of the drying box. It is a kind of Ideal drying system. .

Description of drawings

In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following documents are only For the embodiments of the present invention, those skilled in the art can also obtain other drawings according to the provided drawings without any creative effort.

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

Fig. 2 is a diagram of the high and low temperature energy supply system provided by the present invention.

In the figure: 1. Solar collector; 2. Collector circulating water pump; 3. Temperature difference controller; 4. Heat storage pump; 5. Temperature difference controller; 6. Solenoid valve; 7. Solenoid valve; 8. High temperature heat storage Water tank; 9. Electric heating of high temperature hot water storage tank; 10. Solenoid valve; 11. Solenoid valve; 12. Temperature difference controller; 13. Low temperature hot water storage tank; 14. Solenoid valve; 15. Solenoid valve; 16. Low temperature Electric heating of hot water storage tank; 17. Solenoid valve; 18. Temperature difference controller; 19. Compensation evaporator; 20. Solenoid valve; 21. Compressor; 22. Condenser; 23. Condenser fan; 24. Throttling Valve; 25. Evaporator; 26. Evaporator fan; 27. Return air fan; 28. Drying box; 29. Material rack; 30. Drain hole; 31. Detachable frame; 33. Dehumidification evaporator.

Detailed ways

The present invention will be described in further detail below in conjunction with accompanying drawings and examples.

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

As shown in Figure 1, the heat pump drying system for solar energy and runner dehumidification graded replenishment in the present invention is composed of a runner dehumidification replenishment system, a solar heat collector and an air source heat pump system, which includes a drying box internal circulation and adsorption material analysis.

First, the solar collector 1 is fixedly installed facing south in an open and unsheltered area, the outlet of the collector 1 is connected to the high-temperature hot water storage tank 8, and then to the low-temperature energy storage tank 13, the inlet of the collector 1 is connected to the low-temperature storage tank 8. The bottom of the hot water storage tank 13 is connected and a circulation pump 2 is installed in the middle. The temperature difference controller 3 monitors the outlet temperature of the collector through a temperature sensor, and controls the start and stop of the circulation pump 2 through the temperature difference.

Secondly, by monitoring the ambient temperature, humidity, and the heat transfer capacity of the air source heat pump for dynamic energy replenishment drying system, the temperature change is monitored by the temperature difference controller 3 and 5, and the operation of the energy replenishment system and the operation of the solenoid valve 7 or 6 are adjusted. The opening degree controls how much heat is replenished.

Then, select the corresponding water tank for energy replenishment, the plate evaporator 19 for energy replenishment is connected in parallel with the evaporator 25 in the air source heat pump drying system, and the dehumidification evaporator 33 is connected to the energy replenishment plate evaporator through the electromagnetic valve 20 The rear end of 19 and the front end of evaporator 25 have a maximum opening of solenoid valve 20 half open, and the circulation direction of the refrigerant is just opposite to the circulation direction of the supplementary hot water.

Finally, the high-temperature and humid air in the drying box 28 passes through the return air fan 27, and the lithium chloride-silica gel composite material absorbs a certain amount of water on the lithium chloride-silica gel layer 32 to evaporate, and then passes through the dehumidification evaporator 33 for heat exchange. , the working medium in the dehumidification evaporator 33 absorbs heat, and at the same time, the humid air condenses into water, which is discharged through the drain hole 30, and the heated working medium is sent to the front end of the evaporator 25 to increase the heat exchange mass flow rate. So far, a solar-assisted air-source heat pump drying system under large temperature difference based on phase change material rotor dehumidification and energy replenishment has been completed.

Specifically, during the day when the solar energy is sufficient, the radiation intensity is sufficient, and the environment is stable and not lower than 5°C, the air source heat pump system is used to drive the compressor 21 in the drying system to work, and the heat is released to the drying box through the fan 23 at the condenser 22. It is used to heat up and dry, and at the same time, the solar thermal storage system performs energy storage work. The heat collector 1 absorbs solar energy to heat the water in the high-temperature hot water storage tank 8 and the low-temperature hot water storage tank 13, and passes through the circulating water pump 2 of the thermal collection storage system and 4 for water circulation, while using temperature difference controllers 3 and 5 to monitor the temperature variation to ensure that solar photovoltaics absorb solar energy during the day and convert it into hot water for storage in storage tanks, storing enough heat for use at night and in low temperature conditions. At night, the heat collector 1 cannot absorb solar energy, the circulating water pumps 2 and 4 of the heat collection storage system are turned off, and the energy storage system stops storing energy. At this ambient temperature, when the drying system is in stable operation, the air source heat pump system has been used to dry the entire drying system.

Specifically, in cloudy weather or in an environment with a large temperature difference at night, the solar radiation during the day is not sufficient. According to the intensity of solar irradiance, when the radiation is good and the ambient temperature is greater than 5°C, first drive the air source heat pump drying system When the compressor 21 of the air source heat pump drying system is monitored to reduce the heat exchange rate of the evaporator 25 and the ambient temperature is lower than 5°C, the high and low temperature energy replenishment system will work, and the heat exchange signal of the temperature detector 18 will be regulated and supplemented. The amount of energy and the level of temperature, select the opening of the solenoid valve 10 or 15 before the high-temperature hot water storage tank 8 or the low-temperature hot water storage tank 13, and transfer the stored hot water to the energy-enhancing plate heat exchanger 19 for maximum utilization Stored heat, and at the same time prevent the plate heat exchanger 19 from being damaged due to overheating after the water is directly passed into the plate heat exchanger, and the return water returns to the water tank or the heat collector 1 according to the temperature difference controller 12, and this cycle is a complete energy replenishment cycle; It ensures the drying system in cloudy weather and heat pump heating performance attenuation fluctuations, low efficiency problems and stable drying rate of the drying box, ensuring that the temperature of the drying box is always at the set temperature.

Specifically, in rainy and snowy weather, when solar energy is not enough during the day, and the irradiance is extremely small, the air source heat pump system cannot operate stably, and in this case, the evaporator 25 will appear frosting, which greatly reduces the temperature of the evaporator. At this time, while maintaining the normal operation of the air source heat pump, the temperature difference controller 18 receives a signal, and by monitoring the temperature of the drying box 28, selects the high-temperature hot water storage tank 8 or the low-temperature hot water storage tank according to the calculation 13 Carry out energy replenishment to the plate type energy replenishment heat exchanger 19, and open the corresponding solenoid valve 10 or 15, when there is continuous rainy day and no solar radiation environment, the electric heating 9 or 16 in the water tank can be started, and the The temperature range corresponding to the heating of the water tank for energy replenishment ensures the effect of energy replenishment and the utilization rate of heat; the temperature of the drying box is kept at the set temperature through the hierarchical energy replenishment system, which solves the problem of heat pump heating under the conditions of plateau, severe cold, and large temperature difference Fluctuations in performance decay, issues with lower efficiencies and drying rates in stable ovens.

The above description is only the preferred embodiment found by the present invention through theoretical calculation and experimental comparison, and does not limit the present invention in any form. Although the present invention has been disclosed above with the preferred embodiment, it is not intended to limit the present invention. Invention, any skilled person familiar with this profession, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all without departing from the present invention The content of the technical solution of the invention, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to the scope of the technical solution of the present invention.

Claims (8)

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.

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