CN111365979A - Control method of bypass closed type variable frequency heat pump drying equipment - Google Patents
Control method of bypass closed type variable frequency heat pump drying equipment Download PDFInfo
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- CN111365979A CN111365979A CN202010205520.1A CN202010205520A CN111365979A CN 111365979 A CN111365979 A CN 111365979A CN 202010205520 A CN202010205520 A CN 202010205520A CN 111365979 A CN111365979 A CN 111365979A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/06—Controlling, e.g. regulating, parameters of gas supply
- F26B21/10—Temperature; Pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B30/00—Heat pumps
- F25B30/02—Heat pumps of the compression type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
- F25B49/022—Compressor control arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/02—Circulating air or gases in closed cycles, e.g. wholly within the drying enclosure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/06—Controlling, e.g. regulating, parameters of gas supply
- F26B21/08—Humidity
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/06—Controlling, e.g. regulating, parameters of gas supply
- F26B21/12—Velocity of flow; Quantity of flow, e.g. by varying fan speed, by modifying cross flow area
Abstract
The invention relates to a control method of bypass type closed frequency conversion heat pump drying equipment, which is characterized by comprising the following steps: setting drying process parameters in the controller, namely setting air inlet temperature T of circulating air in the drying chamber0Setting air inlet humidity phi0And a set air humidity difference value delta phi 'and a set air temperature difference value delta T' of the circulating air entering and exiting the drying bin; the controller detects the actual conditions according to the air inlet temperature sensor and the air inlet humidity sensorAir inlet temperature T1And actual air inlet humidity phi1By comparing the actual air inlet temperature T1And setting the air inlet temperature T0The frequency of the inverter compressor is adjusted according to the magnitude of the frequency; the controller adjusts the frequency of the variable-frequency circulating fan by comparing the actual air humidity change value delta phi of the circulating air entering and exiting the drying bin with the set air humidity difference value delta phi 'and the actual air temperature change value delta T with the set air temperature difference value delta T'. The advantages are that: and under the condition of meeting the drying process parameters, the energy conservation of the operation of the drying equipment is realized.
Description
Technical Field
The invention relates to a control method of a drying device of a variable frequency heat pump, and relates to the field of energy conservation of heat pumps.
Background
The heat pump drying technology has been widely applied to the drying processing of food, agricultural products and the like, and one of the obvious characteristics in the drying processing of the products is that the heating load change in the whole processing process is large, and in addition, the drying process parameters (the temperature and the humidity of circulating air) have large influence on the drying rate and the product quality.
At present, a fixed-frequency heat pump technology is mostly adopted in heat pump drying equipment, the adaptability of the heat pump technology to the requirements of a drying process is poor, the drying rate and the product quality are difficult to meet the design requirements, and the energy consumption of the drying equipment is high. Therefore, the drying technology of the variable frequency heat pump with better heating load adjusting capacity is gradually applied, and although the variable frequency heat pump solves the problem of adjusting the heating load, the system optimization control is needed to better meet the requirements of setting process parameters and realizing the energy saving of equipment operation. In the bypass type closed frequency conversion heat pump drying equipment, frequency control of the frequency conversion compressor, control of circulating air quantity, control of circulating air temperature and humidity, control of bypass air quantity and the like are involved, so that how to realize system control on the drying equipment has important significance on the performance of the drying equipment.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a control method of bypass type closed frequency conversion heat pump drying equipment, which can automatically adjust the compressor frequency, the circulating fan frequency and the air volume distribution proportion of an air volume bypass valve of the drying equipment by a control system according to the set drying process parameter requirements, and realize the energy saving of the operation of the drying equipment under the condition of meeting the drying process parameter.
In order to achieve the purpose, the technical scheme of the invention is realized by the control method of the bypass type closed frequency conversion heat pump drying equipment, wherein the drying equipment comprises a frequency conversion compressor, a condenser, a throttle valve, an evaporator, an air volume bypass valve, a frequency conversion circulating fan, a drying bin, a controller, an air inlet temperature sensor, an air inlet humidity sensor, an air outlet temperature sensor and an air outlet humidity sensor; wherein the air inlet temperature sensor and the air inlet humidity sensor respectively sense the air inlet temperature T of the drying bin1And air inlet humidity phi1The air outlet temperature sensor and the air outlet humidity sensor respectively sense the air outlet temperature T of the drying bin2And air outlet humidity phi2(ii) a The condenser is characterized in that the refrigerant in the condenser exchanges heat with circulating air, the circulating air is subjected to equal-humidity heating, the refrigerant in the evaporator exchanges heat with the circulating air, the circulating air is subjected to dehumidification cooling, and condensed water is discharged; the drying equipment control method comprises the following steps:
firstly, drying process parameters are set in a controller, namely the set air inlet temperature T of the circulating air of the drying chamber0Setting air inlet humidity phi0And a set air humidity difference value delta phi 'and a set air temperature difference value delta T' of the circulating air entering and exiting the drying bin;
the controller detects the actual air inlet temperature T according to the air inlet temperature sensor and the air inlet humidity sensor1And actual air inlet humidity phi1By comparing the actual air inlet temperature T1And setting the air inlet temperature T0When T is less than or equal to the frequency of the inverter compressor1＞T0When T is less than T, the frequency of the inverter compressor is reduced1＜T0Increasing the frequency of the variable frequency compressor; by comparing the actual air inlet humidity phi1And setting air inlet humidity phi0The distribution ratio of straight-through air volume to bypass air volume of the air volume bypass valve is adjusted according to the air volume distribution ratio of the straight-through air volume to the bypass air volume, when phi is1＞φ0When the air quantity bypass valve is used, the straight air quantity proportion is increased
φ1＜φ0When the air quantity bypass valve is used, the straight-through air quantity proportion is reduced;
(III) the controller compares the actual air humidity change values of the circulating air entering and exiting the drying bin
Δφ（Δφ=φ1-φ2) The magnitude of the difference Δ Φ' from the set air humidity, and the actual air temperature change value Δ T (Δ T = T)1-T2) Adjusting the frequency of the variable-frequency circulating fan according to the set air temperature difference delta T'; in the adjustment process, the deviation between Δ T and Δ T 'is used as a limiting control parameter, and the deviation between Δ Φ and Δ Φ' is used as a process control parameter, that is, in the adjustment process: (a) under the condition that delta T is less than delta T ', reducing the frequency of the variable-frequency circulating fan when delta phi is less than delta phi ', and improving the frequency of the variable-frequency circulating fan when delta phi is more than delta phi '; (b) and once the condition that the delta T is more than or equal to the delta T 'occurs, increasing the frequency of the variable-frequency circulating fan to enable the delta T to be less than the delta T'.
In the technical solution, the setting range of the set air humidity difference Δ Φ 'is-10% to-60%, and the set air humidity difference Δ Φ' may be a fixed value in the whole drying process, or may be different values at different drying stages, and the fixed value in this embodiment is-40%; the set range of the set air temperature difference delta T' is 1-15 ℃, and the air temperature difference is set in the whole drying process
Δ T' may be a fixed value, or may be different values at different drying stages, and in this embodiment, a fixed value of 5 ℃.
Compared with the prior art, the invention has the following advantages:
the control logics of the variable-frequency compressor, the variable-frequency circulating fan and the air quantity bypass valve in the drying equipment are simple, and the energy conservation of the heat pump refrigerating system and the energy conservation of the variable-frequency circulating fan can be realized, so that the energy conservation of the operation of the drying equipment is realized.
Drawings
Fig. 1 is a schematic diagram of a bypass type closed frequency conversion heat pump drying equipment system implemented by the invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
As shown in fig. 1, it is a control method of a bypass type closed frequency conversion heat pump drying device, the drying device includes a frequency conversion compressor 1, a condenser 2, a throttle valve 3, an evaporator 4, an air volume bypass valve 5, a frequency conversion circulating fan 6, a drying cabin 7, a controller 8, an air inlet temperature sensor 9, an air inlet humidity sensor 10, an air outlet temperature sensor 11, an air outlet humidity sensor 12; wherein the air inlet temperature sensor 9 and the air inlet humidity sensor 10 respectively sense the air inlet temperature T of the drying bin 71Air inlet humidity phi1The air outlet temperature sensor 11 and the air outlet humidity sensor 12 respectively sense the air outlet temperature T of the drying bin 72Humidity phi of air outlet2。
In the drying equipment, a variable frequency compressor 1, a condenser 2, a throttle valve 3 and an evaporator 4 form a heat pump system, a refrigerant passes through the variable frequency compressor 1 to the condenser 2, exchanges heat with circulating air in the condenser 2 and is condensed into liquid, a liquid refrigerant passes through the throttle valve 3, is throttled and then reaches the evaporator 4, exchanges heat with the circulating air in the evaporator 4 and is evaporated into gas, and then returns to the compressor 1; in the drying equipment, an air volume bypass valve 5 and a variable-frequency circulating fan 6 form a circulating air system, high-temperature and low-humidity (lower relative humidity) air from a condenser 2 is sent to a drying bin 7 through the variable-frequency circulating fan 6, the heat and moisture exchange is carried out between the circulating air and the dried material in the drying bin 7, the material is gradually dried, the temperature of the circulating air is reduced on one hand, the moisture content of the circulating air is also improved on the other hand, the high-temperature and high-humidity (higher relative humidity) circulating air is distributed through the air volume bypass valve 5, one part of the circulating air is directly communicated, the circulating air is subjected to heat exchange with a refrigerant of a heat pump system through the evaporator 4, the circulating air is dehumidified and cooled, part of water vapor in the air is condensed into water and discharged, the other part of the circulating air is bypassed, the water vapor is directly mixed with the dehumidified and cooled part of the circulating air and then flows to the condenser 2, the circulating air is subjected to equal; the drying equipment control method comprises the following steps:
drying process parameters are set in the controller 8, namely the set air inlet temperature T of the circulating air of the drying chamber 70Setting air inlet humidity phi0And a set air humidity difference value delta phi 'and a set air temperature difference value delta T' of the circulating air entering and exiting the drying bin 7;
the controller 8 detects the actual air inlet temperature T according to the air inlet temperature sensor 9 and the air inlet humidity sensor 101And actual air inlet humidity phi1By comparing the actual air inlet temperature T1And setting the air inlet temperature T0To adjust the frequency of the inverter compressor 1, when T is1＞T0When T is less than T, the frequency of the inverter compressor 1 is reduced1＜T0When the frequency is increased, the frequency of the variable frequency compressor 1 is increased; by comparing the actual air inlet humidity phi1And setting air inlet humidity phi0The distribution proportion of straight-through air volume and bypass air volume of the air volume bypass valve 5 is adjusted according to the size of the air volume bypass valve, when phi is1＞φ0When the wind quantity is increased, the wind quantity through the wind quantity bypass valve 5 is increased by phi1＜φ0In the process, the straight air volume proportion of the air volume bypass valve 5 is reduced;
the controller 8 compares the actual humidity change values of the circulating air entering and exiting the drying chamber 7
Δφ（Δφ=φ1-φ2) The magnitude of the difference Δ Φ' from the set air humidity, and the actual air temperature change value Δ T (Δ T = T)1-T2) Adjusting the frequency of the variable-frequency circulating fan 6 according to the set air temperature difference delta T'; during the regulation, the deviation of Δ T from Δ T' is used as a limiting control parameter,
the deviation between delta phi and delta phi' is used as a process control parameter, i.e. during the adjustment process: (a) at Δ T < >
In case of Δ T', when Δ Φ < Δ Φ ″, the frequency of the variable-frequency circulation fan 6 is reduced, and when Δ Φ > -
When is delta phi', the frequency of the variable-frequency circulating fan 6 is increased; (b) once the case that Δ T is equal to or greater than Δ T 'occurs, Δ T < Δ T' is made by increasing the frequency of the variable-frequency circulating fan 6.
In this embodiment, the set range of the set air humidity difference Δ Φ "is-10% to-60%, and the set air humidity difference Δ Φ" may be a fixed value in the entire drying process, or may be different values in different drying stages, and in this embodiment, the fixed value is-40%; the set range of the set air temperature difference Δ T 'is 1-15 ℃, and the set air temperature difference Δ T' may be a fixed value in the whole drying process, or may be different values at different drying stages, and the fixed value in this embodiment is 5 ℃.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (2)
1. A control method of bypass type closed frequency conversion heat pump drying equipment comprises the steps that the drying equipment comprises a frequency conversion compressor (1), a condenser (2), a throttle valve (3), an evaporator (4), an air volume bypass valve (5), a frequency conversion circulating fan (6), a drying bin (7), a controller (8), an air inlet temperature sensor (9), an air inlet humidity sensor (10), an air outlet temperature sensor (11) and an air outlet humidity sensor (12); wherein the air inlet temperature sensor (9) and the air inlet humidity sensor (10) respectively sense the air inlet temperature T of the drying bin (7)1And air inlet humidity phi1The air outlet temperature sensor (11) and the air outlet humidity sensor (12) respectively sense the air outlet temperature T of the drying bin2And air outlet humidity phi2(ii) a It is characterized in that the refrigerant in the condenser (2) exchanges heat with circulating air, the circulating air is heated in a uniform manner, the refrigerant in the evaporator (4) exchanges heat with the circulating air, the circulating air is dehumidified and cooled, and cold is dischargedCondensing water; the drying equipment control method comprises the following steps:
setting drying process parameters in a controller (8), namely setting air inlet temperature T of circulating air of a drying bin (7)0Setting air inlet humidity phi0And a set air humidity difference delta phi 'and a set air temperature difference delta T' of the circulating air entering and exiting the drying bin (7);
the controller (8) detects the actual air inlet temperature T according to the air inlet temperature sensor (9) and the air inlet humidity sensor (10)1And actual air inlet humidity phi1By comparing the actual air inlet temperature T1And setting the air inlet temperature T0When the frequency of the inverter compressor (1) is adjusted to be T1＞T0When T is greater than T, the frequency of the inverter compressor (1) is reduced1＜T0When the frequency of the variable frequency compressor (1) is increased; by comparing the actual air inlet humidity phi1And setting the humidity of the air inlet
φ0The distribution proportion of straight-through air volume and bypass air volume of the air volume bypass valve (5) is adjusted according to the size of the air volume bypass valve (5), when phi is1＞φ0When the wind quantity is increased, the straight wind quantity proportion of the wind quantity bypass valve (5) is increased when phi is larger1＜φ0When the air quantity bypass valve (5) is used, the direct air quantity proportion is reduced;
(III) the controller (8) compares the actual air humidity change value delta phi (delta phi = phi) of the circulating air entering and exiting the drying bin (7)1-φ2) The magnitude of the difference Δ Φ' from the set air humidity, and the actual air temperature change value Δ T (Δ T = T)1-T2) Adjusting the frequency of the variable-frequency circulating fan (6) according to the set air temperature difference delta T'; in the adjustment process, the deviation between Δ T and Δ T 'is used as a limiting control parameter, and the deviation between Δ Φ and Δ Φ' is used as a process control parameter, that is, in the adjustment process: (a) in the case of Δ T < Δ T', when Δ Φ < Δ Φ ″, reducing the frequency of the variable-frequency circulating fan (6), and when Δ Φ > Δ Φ ″, increasing the frequency of the variable-frequency circulating fan (6); (b) once Δ T ≧ occurs
In the case of Δ T ', Δ T < Δ T' is made by increasing the frequency of the variable-frequency circulating fan (6).
2. The control method of the bypass-type closed-type frequency-conversion heat pump drying equipment according to claim 1, wherein the set range of the set air humidity difference Δ Φ 'is-10% to-60%, the set air humidity difference Δ Φ' may be a fixed value during the whole drying process, or may be a different value at different drying stages, and in this embodiment, the fixed value is-40%; the set range of the set air temperature difference Δ T 'is 1-15 ℃, and the set air temperature difference Δ T' may be a fixed value in the whole drying process, or may be different values at different drying stages, and the fixed value in this embodiment is 5 ℃.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010205520.1A CN111365979A (en) | 2020-03-23 | 2020-03-23 | Control method of bypass closed type variable frequency heat pump drying equipment |
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| CN202010205520.1A CN111365979A (en) | 2020-03-23 | 2020-03-23 | Control method of bypass closed type variable frequency heat pump drying equipment |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112611174A (en) * | 2020-11-30 | 2021-04-06 | 扬州大学 | Multi-energy complementary drying control system |
| CN115523750A (en) * | 2022-08-09 | 2022-12-27 | 青岛海尔空调器有限总公司 | Heat pump dryer control method and device based on air inlet temperature |
| CN115540582A (en) * | 2022-08-09 | 2022-12-30 | 青岛海尔空调器有限总公司 | Drying adjustment method, dryer, electronic device, and storage medium |
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| US20060179676A1 (en) * | 2003-09-29 | 2006-08-17 | Michael Goldberg | Heat pump clothes dryer |
| CN106567237A (en) * | 2015-10-10 | 2017-04-19 | 杭州三花家电热管理系统有限公司 | Refrigerant system, drying device, and control method of drying device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112611174A (en) * | 2020-11-30 | 2021-04-06 | 扬州大学 | Multi-energy complementary drying control system |
| CN115523750A (en) * | 2022-08-09 | 2022-12-27 | 青岛海尔空调器有限总公司 | Heat pump dryer control method and device based on air inlet temperature |
| CN115540582A (en) * | 2022-08-09 | 2022-12-30 | 青岛海尔空调器有限总公司 | Drying adjustment method, dryer, electronic device, and storage medium |
| CN115540582B (en) * | 2022-08-09 | 2024-04-23 | 青岛海尔空调器有限总公司 | Drying adjustment method, dryer, electronic device and storage medium |
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