CN113854612B - Drying unit control method, readable storage medium and drying unit - Google Patents
Drying unit control method, readable storage medium and drying unit Download PDFInfo
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- CN113854612B CN113854612B CN202110980463.9A CN202110980463A CN113854612B CN 113854612 B CN113854612 B CN 113854612B CN 202110980463 A CN202110980463 A CN 202110980463A CN 113854612 B CN113854612 B CN 113854612B
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- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
- A24B3/00—Preparing tobacco in the factory
- A24B3/10—Roasting or cooling tobacco
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- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24B—MANUFACTURE OR PREPARATION OF TOBACCO FOR SMOKING OR CHEWING; TOBACCO; SNUFF
- A24B3/00—Preparing tobacco in the factory
- A24B3/04—Humidifying or drying tobacco bunches or cut tobacco
Abstract
The invention discloses a control method of a drying unit, a readable storage medium and the drying unit, wherein the opening degree of an expansion valve is adjusted according to the actual exhaust temperature Td1 of a compressor and the target exhaust temperature Tm1 corresponding to the current roasting section, or the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of a condenser and the target condensation temperature Tm2 corresponding to the current roasting section; the heat pump system can efficiently operate in each baking section, the overall energy consumption of the heat pump system is reduced, and the purposes of energy conservation and emission reduction are achieved.
Description
Technical Field
The invention belongs to the technical field of drying, and particularly relates to a drying unit control method, a readable storage medium and a drying unit.
Background
With the development of economy, the concept of environmental protection becomes more important. In the field of tobacco drying, energy-saving modification work is being greatly popularized, and the replacement of a coal-fired boiler by an air-source heat pump becomes a major trend of the industry.
The whole process of tobacco drying requires large temperature difference, the drying temperature of the curing barn in each drying stage is different from 30-70 ℃, the condensation temperature of the corresponding heat pump drying unit set spans 35-75 ℃, and the characteristics of large temperature difference, output according to requirements and the like exist; the current control means can not well meet the scene operation requirements of the tobacco drying machine set, and the machine set capacity and energy efficiency can not be brought into the best state according to the requirements of each drying process.
At present, a tobacco drying heat pump system usually adopts a thermal expansion valve or an electronic expansion valve for throttling, and the opening degree of the electronic expansion valve is adjusted by controlling the superheat degree of an outlet of an evaporator by using the control idea of a household comfortable air conditioner. Because actual baking of tobacco is generally carried out in summer, the ambient temperature of an outdoor evaporation side is relatively stable, generally about 25 ℃, the fluctuation is small, but the temperature of a condensation side is the temperature, the temperature spans a range of 30-70 ℃ according to different baking stages of tobacco leaves, and a throttle expansion valve adopts a control means of adjusting the opening of a valve in the form of superheat degree of an evaporator outlet, so that the optimal state of a unit in each baking stage cannot be ensured, and the baking process and the whole energy consumption are further influenced.
Disclosure of Invention
The invention provides a control method of a drying unit, which solves the problem of high energy consumption in the prior art.
In order to solve the technical problems, the invention adopts the following technical scheme:
a control method of a drying unit comprises a plurality of sets of heat pump systems, wherein each set of heat pump system comprises a compressor, a condenser, an expansion valve and an evaporator, and the control method comprises the following steps:
for each set of heat pump system after starting, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section:
if Td1 is less than Tm1-k1, reducing the opening degree of the expansion valve;
if Tm1-k1 is not less than Td1 and less than Tm1+ k1, maintaining the opening degree of the expansion valve;
if Td1 is larger than or equal to Tm1+ k1, the opening degree of the expansion valve is increased;
wherein k1 is a constant greater than 0;
alternatively, the first and second electrodes may be,
for each set of heat pump system after starting, the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current baking section:
if Td2 is less than Tm2-k2, reducing the opening degree of the expansion valve;
if Tm2-k2 is more than or equal to Td2 and less than Tm2+ k2, the opening degree of the expansion valve is kept;
if Td2 is more than or equal to Tm2+ k2, the opening degree of the expansion valve is increased;
wherein k2 is a constant greater than 0.
Further, the target exhaust temperature Tm1= Tg0+ T1 corresponding to the current roasting section;
wherein Tg0 is the target dry bulb temperature in the curing barn corresponding to the current curing section; t1 is a preset superheat threshold value;
the target condensation temperature Tm2= Tg0+ T2 corresponding to the current roasting section;
wherein T2 is a preset superheat threshold value; t2 is less than T1.
Still further, k1= k2, and the numeric area of k1 and k2 is 1.5 to 2.5.
Further, when the opening degree of the expansion valve is decreased, the opening degree of the expansion valve is decreased at a set speed;
when the opening degree of the expansion valve is increased, the opening degree of the expansion valve is increased at a set speed.
Further, when the compressor is in a standby state and is not started, the opening degree of the expansion valve is a set standby opening degree;
when the compressor is started within a set time, the opening degree of the expansion valve is a reference opening degree corresponding to the current roasting section;
after the compressor is started for a set time, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section, or the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current roasting section.
Further, when the dryer group includes a plurality of sets of heat pump systems, the control method further includes:
acquiring the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section;
and determining the starting set number of the heat pump system according to the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section.
Still further, when the dryer unit includes two sets of heat pump systems, determining the number of starting sets of heat pump systems according to the actual dry bulb temperature in the baking room and the target dry bulb temperature in the baking room corresponding to the current baking section specifically includes:
when the actual dry bulb temperature in the curing barn is less than Tg 0-delta Tg, two sets of heat pump systems are started;
when Tg 0-delta Tg is less than or equal to the actual dry bulb temperature in the baking room and less than Tg0-k3 delta Tg, starting one set of heat pump system;
when Tg0-k3 Δ Tg is less than or equal to the actual dry bulb temperature in the curing barn which is less than Tg0+ k3 Δ Tg, the start-stop states of the two sets of heat pump systems are kept;
when the actual dry bulb temperature in the curing barn is more than or equal to Tg0+ k3 × Δ Tg, both the two sets of heat pump systems are stopped;
wherein, the first and the second end of the pipe are connected with each other,
tg0 is the target dry-bulb temperature in the curing barn corresponding to the current curing section;
the delta Tg is the return difference of the temperature control precision of the target dry ball in the curing barn corresponding to the current curing section;
k3 is a constant, and 0 < k3 < 1.
Further, k3=0.5.
A readable storage medium having a readable program stored therein, the readable program when executed, implementing the dryer group control method.
A dryer assembly comprising:
each set of heat pump system comprises a compressor, a condenser, an expansion valve and an evaporator;
a readable storage medium storing a readable program;
and a controller executing the readable program to implement the dryer group control method.
Compared with the prior art, the invention has the advantages and positive effects that: according to the control method of the drying unit, the readable storage medium and the drying unit, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current baking section, or the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current baking section; the heat pump system can efficiently operate in each baking section, the overall energy consumption of the heat pump system is reduced, and the purposes of energy conservation and emission reduction are achieved.
Other features and advantages of the present invention will become more apparent from the detailed description of the embodiments of the present invention when taken in conjunction with the accompanying drawings.
Drawings
Fig. 1 is a schematic diagram of an embodiment of a dryer group according to the present invention;
fig. 2 is a flowchart of an embodiment of a control method for a dryer group according to the present invention;
fig. 3 is a flowchart of another embodiment of a dryer group control method according to the present invention;
fig. 4 is a flowchart of a dryer group control method according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and embodiments.
It should be noted that in the description of the present invention, the terms of direction or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, which are only for convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The invention provides a drying machine set control method, a readable storage medium and a drying machine set, aiming at the problems that the condensation temperature span of a heat pump system is large, the optimal operation state cannot be exerted in each baking section, and the energy consumption is high. Hereinafter, a control method of a dryer group, a readable storage medium, and a dryer group according to the present invention will be described in detail with reference to the accompanying drawings.
A readable storage medium storing a readable program, the readable program implementing the dryer group control method of the first and second embodiments when executed.
The drying machine set comprises a controller, a readable storage medium and a plurality of sets of heat pump systems.
And a plurality of sets of heat pump systems are connected in parallel. Each set of heat pump system comprises a compressor, a condenser, an expansion valve, an evaporator and the like which form a refrigerant circulating pipeline; an outer fan is arranged on the leeward side of the evaporator. The expansion valve is used for throttling the refrigerant, and in the following two embodiments, the expansion valve is an electronic expansion valve. Wherein, the compressor, the evaporator and the external Fan are all arranged in the external space, the condenser is arranged in the main circulating air duct of the curing barn, and the main circulating air duct is also internally provided with a main circulating Fan1. And a temperature sensor is arranged at the air outlet of the compressor and used for detecting the actual air outlet temperature of the compressor. The condenser is provided with a temperature sensor for detecting the actual condensing temperature of the condenser; alternatively, the actual condensing pressure of the condenser is detected by a pressure sensor and converted into the actual condensing temperature.
Suppose that the heat pump system is provided with two sets: a heat pump system a and a heat pump system B, see fig. 1.
The heat pump system A comprises a compressor A, a condenser A, an expansion valve VA, an evaporator A and the like which form a refrigerant circulating pipeline; an external fan FanA is provided on the leeward side of the evaporator a. A temperature sensor SA is provided at the discharge port of the compressor a for detecting the actual discharge temperature of the compressor a. The condenser a is provided with a temperature sensor for detecting the actual condensing temperature of the condenser a.
The heat pump system B comprises a compressor B, a condenser B, an expansion valve VB, an evaporator B and the like which form a refrigerant circulating pipeline; an outer fan FanB is provided on the leeward side of the evaporator B. A temperature sensor SB is provided at the discharge port of the compressor B for detecting the actual discharge temperature of the compressor B. The condenser B is provided with a temperature sensor for detecting an actual condensing temperature of the condenser B.
The compressor A, the compressor B, the evaporator A, the evaporator B, the outer fan A and the outer fan B are all arranged in the external space. The evaporator B is arranged on the windward side of the evaporator A, and the air flow in the external space firstly passes through the evaporator B and then passes through the evaporator A under the driving of the outer fan A and the outer fan B.
The condenser A and the condenser B are arranged in the main circulation air duct, the condenser B is arranged on the windward side of the condenser A, and under the driving of the main circulation Fan Fan1, airflow in the main circulation air duct firstly passes through the condenser B and then passes through the condenser A.
Temperature and humidity sensor in the roast room gathers dry bulb temperature and wet bulb temperature to send the dry bulb temperature and the wet bulb temperature who gathers to drying unit's controller.
The readable storage medium of the dryer group stores readable programs; the controller controls the operation of each set of heat pump system, the main circulating fan and the whole drying unit; the controller executes a readable program in a readable storage medium to implement the dryer group control methods of the first and second embodiments.
The first embodiment,
The method for controlling a dryer group of the embodiment mainly includes the following steps, as shown in fig. 2.
For each set of heat pump system after startup, the following steps are performed:
step S11: and acquiring the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section.
Step S12: adjusting the opening degree of the expansion valve according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section, specifically comprising:
s12-1: if Td1 is less than Tm1-k1, which indicates that the actual exhaust temperature of the compressor is too low, the opening degree of the expansion valve is reduced to reduce the refrigerant circulation amount, thereby increasing the actual exhaust temperature of the compressor.
S12-2: if Tm1-k1 is not less than Td1 and less than Tm1+ k1, which indicates that the actual exhaust temperature of the compressor is in the normal range, the opening degree of the expansion valve is maintained.
S12-3: if Td1 is larger than or equal to Tm1+ k1, which indicates that the actual exhaust temperature of the compressor is too high, the opening degree of the expansion valve is increased to increase the refrigerant circulation amount, so that the actual exhaust temperature of the compressor is reduced.
Wherein k1 is a constant greater than 0.
According to the control method of the drying unit in the embodiment, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current baking section, and when the Td1 is smaller than Tm1-k1, the opening degree of the expansion valve is reduced; when Tm1-k1 is more than or equal to Td1 and less than Tm1+ k1, the opening degree of the expansion valve is kept; when Td1 is larger than or equal to Tm1+ k1, the opening degree of the expansion valve is increased; thereby controlling the exhaust temperature of the compressor within a normal range and ensuring the normal operation of the heat pump system; in addition, the control method of the embodiment combines the target exhaust temperature corresponding to the current baking section, so that the heat pump system can operate efficiently in each baking section, the tobacco drying quality and process are improved, the overall energy consumption of the heat pump system is reduced, and the purposes of energy conservation and emission reduction are achieved.
According to the control method of the drying unit, the opening degree of the expansion valve is intelligently and dynamically adjusted by combining the temperature requirements of each tobacco drying stage, so that the heat pump system operates at the most efficient point in each drying stage, the capacity and the energy efficiency of the heat pump system are fully exerted, the drying efficiency is improved, and the energy is saved and the efficiency is improved. The control method of the drying unit ensures continuous and efficient operation of the heat pump system, saves energy, reduces consumption and reduces operation cost; the baking efficiency is improved, the baking speed is improved, and the income of tobacco growers is increased.
In this embodiment, k1 is in the range of 1.5 to 2.5 in degrees centigrade. k1, the opening of the expansion valve is accurately and stably adjusted by selecting the value range. As a preferable embodiment of the present embodiment, k1=2 ℃.
In this embodiment, the target exhaust temperature Tm1= Tg0+ T1 corresponding to the current baking section.
Wherein Tg0 is the target dry bulb temperature in the curing barn corresponding to the current curing section; t1 is a preset superheat threshold value.
In the material drying process, each drying section has corresponding target dry-bulb temperature and target wet-bulb temperature. By selecting the target exhaust temperature calculation formula, the target exhaust temperature of the compressor is related to the target dry bulb temperature of the baking room, so that the heat pump system can be further ensured to efficiently operate in each baking section, and the actual dry bulb temperature in the baking room meets the requirement.
As a preferable configuration of the present embodiment, when the opening degree of the expansion valve is decreased, the opening degree of the expansion valve is decreased at a set speed; namely, the opening degree of the expansion valve is reduced at a constant speed, so that the circulation volume of the refrigerant is stably reduced, and the stable operation of the heat pump system is ensured. For example, the opening is decreased by 1 step every 5 seconds.
When the opening degree of the expansion valve is increased, the opening degree of the expansion valve is increased at a set speed, namely the opening degree of the expansion valve is increased at a constant speed, so that the circulation volume of the refrigerant is stably increased, and the stable operation of the heat pump system is ensured. For example, the opening is increased by 1 step every 5 seconds.
For each heat pump system, in order to ensure that the system can be started and operated smoothly, and the opening degree of the expansion valve is adjusted stably, the control method of the embodiment further includes the following steps:
(1) When the compressor is in a standby state and is not started, the opening degree of the expansion valve is a set standby opening degree; if the standby opening is 200 steps. In this embodiment, the full-opening degree of the expansion valve is 480 steps.
(2) And in a set time (such as 5 minutes after starting) after the compressor is started, the opening degree of the expansion valve is the reference opening degree corresponding to the current baking section.
(3) After the compressor is started for a set time (for example, after 5 minutes from the start), the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current baking section.
As shown in table 1, the tobacco leaf curing process includes three stages: yellowing stage, color fixing stage and tendon drying stage. Wherein the yellowing stage comprises a baking section 1, a baking section 2 and a baking section 3; the color fixing stage comprises a baking section 4, a baking section 5, a baking section 6 and a baking section 7; the tendon drying stage comprises a baking section 8, a baking section 9 and a baking section 10.
Each of the roasting sections has a corresponding target dry-bulb temperature, and a reference opening degree of the electronic expansion valves a and B.
TABLE 1
In this embodiment, when the dryer group includes a plurality of sets of heat pump systems, the control method of this embodiment further includes the following steps, which are shown in fig. 3.
Step S21: and acquiring the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section.
Step S22: and determining the starting set number of the heat pump system according to the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section.
The starting set number of the heat pump system is determined by combining the target dry bulb temperature corresponding to the baking sections, so that the temperature and humidity requirements of the baking room can be met, the heating effect of the heat pump system in each baking section is ensured, the waste of energy sources is avoided, the overall energy consumption of the heat pump system is reduced, and the aims of energy conservation and emission reduction are fulfilled.
When the drying unit comprises two sets of heat pump systems, the heat pump system A and the heat pump system B are connected in parallel, and two modes of single-system operation heat supply and double-system operation heat supply are automatically carried out according to the load requirement of the curing barn; in order to balance the running time of the two systems, the heat pump system A and the heat pump system B adopt alternate starting control.
Therefore, when the dryer group includes two sets of heat pump systems, S22 specifically includes the following steps:
(22-1) when the actual dry bulb temperature in the curing barn is less than Tg 0-delta Tg, the actual dry bulb temperature in the curing barn is very low, and two sets of heat pump systems are required to be started. And if the heat pump system A is already in operation at the moment, the heat pump system B is restarted to realize the double-system heat supply operation. Namely, the compressor A and the compressor B operate, the outer fans FanA and FanB operate in high wind, and the main circulating Fan Fan1 operates in high wind, so that double-system heat supply operation is carried out, and the dry bulb temperature in the baking room is quickly increased.
(22-2) when Tg 0-delta Tg is less than or equal to the actual dry bulb temperature < Tg0-k3 delta Tg in the curing barn, the actual dry bulb temperature in the curing barn is slightly lower, and one set of heat pump system is started. If the heat pump system A is started to carry out single-system heat supply operation, namely the compressor A is started, the external Fan FanA runs in high wind, and the main circulating Fan Fan1 of the curing barn runs in high wind, and single-system running heat supply is carried out.
In order to balance the operation time of the two heat pump systems, the heat pump system A and the heat pump system B are alternately started, namely the heat pump system A is started firstly at this time, the heat pump system B is started next time, and the two systems operate according to the required rotation value.
(22-3) when Tg0-k3 delta Tg is less than or equal to actual dry bulb temperature < Tg0+ k3 delta Tg in the baking room, the actual dry bulb temperature in the baking room is relatively proper, and the current start-stop states of the two sets of heat pump systems are kept.
(22-4) when the actual dry bulb temperature in the baking room is more than or equal to Tg0+ k3 delta Tg, the actual dry bulb temperature in the baking room reaches the target requirement, at the moment, the two sets of heat pump systems are stopped, namely the compressor A and the compressor B are stopped, the external fans FanA and FanB are stopped, the main circulating Fan Fan1 of the baking room runs in high wind, the normal circulation of hot air in the baking room is kept, and the next round of operation is carried out in real time according to the detection result.
Wherein the content of the first and second substances,
tg0 is the target dry bulb temperature in the curing barn corresponding to the current curing section;
the delta Tg is the return difference of the temperature control precision of the target dry ball in the curing barn corresponding to the current curing section;
k3 is a constant, and 0 < k3 < 1.
By designing the above (22-1) - (22-4), the number of the starting sets of the heat pump system is determined according to the relation between the actual dry bulb temperature in the baking room and Tg 0-delta Tg, tg0-k3 delta Tg and Tg0+ k3 delta Tg, so that the heat supply in the baking room can be ensured, and the energy waste caused by too many starting sets of the heat pump system can be avoided.
As a preferred embodiment of the present embodiment, k3=0.5.
Namely, when the actual dry bulb temperature in the curing barn is less than Tg 0-delta Tg, two sets of heat pump systems are started.
When Tg 0-delta Tg is less than or equal to actual dry bulb temperature in the curing barn and less than Tg0-0.5 x delta Tg, one set of heat pump system is started.
And when the Tg is 0-0.5 × Δ Tg is less than or equal to the actual dry bulb temperature in the baking room and is less than Tg0+0.5 × Δ Tg, maintaining the current start-stop states of the two sets of heat pump systems.
When the actual dry bulb temperature in the curing barn is more than or equal to Tg0+0.5 × Δ Tg, both the two heat pump systems are stopped.
By selecting k3=0.5, the range division can be balanced, and the number of the starting sets of the heat pump system can be determined accurately.
The control method of the drying unit in the embodiment dynamically adjusts the opening of the electronic expansion valve according to the actual exhaust temperature of the compressor and the target dry-bulb temperature Tg0 of the baking room in each baking process stage, so as to ensure the high-efficiency operation of the drying unit, and specifically comprises the following steps:
1. standby control: when the compressor A/B is in a standby state and is not started, the electronic expansion valve A/B is in a standby opening degree of 200 steps.
2. Starting control: and within 5min after the A/B of the compressor is started, the A/B of the electronic expansion valve is in the standard opening degree. Reference opening degree setting principle: different reference opening degrees are set according to the target dry bulb temperature Tg0 set by different baking sections, as shown in table 1.
After 5min of operation, calculating the target exhaust temperature according to the target dry-bulb temperature Tg0 set by the corresponding baking section, namely: the target exhaust temperature Tm1 defines: tm1= (Tg 0+ T1) ° c.
Starting the compressor A/B, after the electronic expansion valve A/B stably operates for 5min at a reference opening degree, comparing the actual exhaust temperature Td1 of the compressor A/B with the target exhaust temperature Tm1 corresponding to the current baking section, and adjusting the opening degree of the electronic expansion valve A/B as follows:
when Td1 is less than (Tm 1-2) DEG C, the opening degree of the electronic expansion valve A/B is reduced by 1 step every 5 seconds;
when Tm1-2 is less than or equal to Td1 and less than Tm1+2, the electronic expansion valve A/B keeps the current opening degree unchanged;
when Td1> (Tm 1+ 2) ° C, the opening degree of the electronic expansion valve A/B is increased by 1 step every 5 seconds.
3. And (3) shutdown control: when the actual dry bulb temperature in the curing barn is more than or equal to Tg0+0.5 delta Tg, the dry bulb temperature in the curing barn reaches the target requirement, at the moment, the compressor A/B stops running, the electronic expansion valve A/B enters 200 steps of standby opening, and the next starting running is waited.
Example II,
The method for controlling a dryer group of the embodiment mainly includes the following steps, as shown in fig. 4.
For each set of heat pump system after starting, executing the following steps:
step S31: and acquiring the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current roasting section.
Step S32: adjusting the opening degree of the expansion valve according to the actual condensing temperature Td2 of the condenser and the target condensing temperature Tm2 corresponding to the current roasting section, specifically comprising:
s32-1: if Td2 is less than Tm2-k2, which indicates that the actual condensing temperature of the condenser is too low, the opening degree of the expansion valve is reduced to reduce the circulating amount of the refrigerant, so that the actual condensing temperature of the condenser is increased.
S32-2: if Tm2-k2 is more than or equal to Td2 and less than Tm2+ k2, the actual condensing temperature of the condenser is in a normal range, and the opening degree of the expansion valve is kept.
S32-3: if Td2 is larger than or equal to Tm2+ k2, which indicates that the actual condensing temperature of the condenser is too high, the opening degree of the expansion valve is increased to increase the circulating amount of the refrigerant, so that the actual condensing temperature of the condenser is reduced.
Wherein k2 is a constant greater than 0.
According to the control method of the drying unit, the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current baking section, and when the Td2 is smaller than the Tm2-k2, the opening degree of the expansion valve is reduced; when Tm2-k2 is more than or equal to Td2 and less than Tm2+ k2, the opening degree of the expansion valve is kept; when Td2 is larger than or equal to Tm2+ k2, the opening degree of the expansion valve is increased; thereby controlling the condensation temperature of the condenser within a normal range and ensuring the normal operation of the heat pump system; in addition, the control method of the embodiment combines the target condensing temperature corresponding to the current baking section, so that the heat pump system can operate efficiently in each baking section, the tobacco drying quality and process are improved, the overall energy consumption of the heat pump system is reduced, and the purposes of energy conservation and emission reduction are achieved.
According to the control method of the drying unit, the opening degree of the expansion valve is intelligently and dynamically adjusted by combining the temperature requirements of each tobacco drying stage, so that the heat pump system operates at the most efficient point in each drying stage, the capacity and the energy efficiency of the heat pump system are fully exerted, the drying efficiency is improved, and the energy is saved and the efficiency is improved. The control method of the drying unit ensures that the heat pump system continuously and efficiently operates, saves energy, reduces consumption and reduces operation cost; the baking efficiency is improved, the baking speed is improved, and the income of tobacco growers is increased.
In this embodiment, k2= k1, and k2 ranges from 1.5 to 2.5 in units of ℃. k2, the opening of the expansion valve is accurately and stably adjusted by selecting the value range. As a preferable aspect of the present embodiment, k2=2 ℃.
In this embodiment, the target condensation temperature Tm2= Tg0+ T2 corresponding to the current roasting stage.
Wherein Tg0 is the target dry-bulb temperature in the curing barn corresponding to the current curing section; t2 is a preset superheat threshold value.
T2 < T1, e.g. T1=15 ℃, T2=9 ℃.
In the material drying process, each baking section has a corresponding target dry-bulb temperature and a target wet-bulb temperature. By selecting the target condensation temperature calculation formula, the target condensation temperature of the condenser is related to the target dry bulb temperature of the baking room, and the heat pump system can be further ensured to efficiently operate in each baking section, so that the actual dry bulb temperature in the baking room meets the requirement.
As a preferable configuration of the present embodiment, when the opening degree of the expansion valve is decreased, the opening degree of the expansion valve is decreased at a set speed; namely, the opening degree of the expansion valve is reduced at a constant speed, so that the circulation volume of the refrigerant is stably reduced, and the stable operation of the heat pump system is ensured. For example, the opening is decreased by 1 step every 5 seconds.
When the opening degree of the expansion valve is increased, the opening degree of the expansion valve is increased at a set speed, namely the opening degree of the expansion valve is increased at a constant speed, so that the circulation volume of the refrigerant is stably increased, and the stable operation of the heat pump system is ensured. For example, the opening is increased by 1 step every 5 seconds.
For each heat pump system, in order to ensure that the system can be started and operated smoothly, and the opening degree of the expansion valve is adjusted stably, the control method of the embodiment further comprises the following steps:
(1) When the compressor is in a standby state and is not started, the opening degree of the expansion valve is a set standby opening degree; for example, the standby opening is 200 steps. In this embodiment, the full-opening degree of the expansion valve is 480 steps.
(2) And when the compressor is started within a set time (such as within 5 minutes after the compressor is started), the opening degree of the expansion valve is the reference opening degree corresponding to the current roasting section.
(3) After the compressor is started for a set time (for example, after 5 minutes from the start), the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current baking section.
The tobacco leaf baking process, the target dry bulb temperature corresponding to each baking section, and the reference opening degree of the expansion valve are shown in table 1 of the first embodiment, and are not described herein again.
The number of starting sets of the heat pump system is determined according to the actual dry bulb temperature in the baking room and the target dry bulb temperature in the baking room corresponding to the current baking section, which is described in the first embodiment and is not described herein again.
According to the control method of the drying unit in the embodiment, the opening of the electronic expansion valve is dynamically adjusted according to the actual condensing temperature of the condenser and the target dry-bulb temperature Tg0 of the baking room in each baking process stage, so that the high-efficiency operation of the drying unit is ensured, and the control method specifically comprises the following steps:
1. standby control: when the compressor A/B is in a standby state and is not started, the electronic expansion valve A/B is in a standby opening degree of 200 steps.
2. Starting control: and within 5min after the A/B of the compressor is started, the A/B of the electronic expansion valve is in the standard opening degree. Reference opening degree setting principle: different reference opening degrees are set according to the target dry-bulb temperature Tg0 set by different baking sections, as shown in Table 1 in example I.
After 5min of operation, calculating the target condensation temperature according to the target dry-bulb temperature Tg0 set by the corresponding baking section, namely: the target condensation temperature Tm2 defines: tm2= (Tg 0+ T2) ° c.
Starting the compressor A/B, after the electronic expansion valve A/B stably operates for 5min at a reference opening, comparing the actual condensation temperature Td2 of the condenser A/B with the target condensation temperature Tm2 corresponding to the current baking section, and adjusting the opening of the electronic expansion valve A/B as follows:
when Td2 is less than (Tm 2-2) DEG C, the opening degree of the electronic expansion valve A/B is reduced by 1 step every 5 seconds;
when Tm2-2 is less than or equal to Td2 and less than Tm2+2, the electronic expansion valve A/B keeps the current opening degree unchanged;
when Td2> (Tm 2+ 2) ° C, the opening degree of the electronic expansion valve A/B is increased by 1 step every 5 seconds.
3. And (3) shutdown control: when the actual dry bulb temperature in the curing barn is more than or equal to Tg0+0.5 × Δ Tg, the dry bulb temperature in the curing barn reaches the target requirement, at the moment, the compressor A/B stops running, the electronic expansion valve A/B enters the standby opening degree for 200 steps, and the next starting operation is waited.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make various changes, modifications, additions and substitutions within the spirit and scope of the present invention.
Claims (4)
1. A control method of a drying unit comprises a plurality of sets of heat pump systems, wherein each set of heat pump system comprises a compressor, a condenser, an expansion valve and an evaporator, and is characterized in that: the control method comprises the following steps:
for each set of heat pump system after starting, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section:
if Td1 is less than Tm1-k1, reducing the opening degree of the expansion valve;
if Tm1-k1 is more than or equal to Td1 and less than Tm1+ k1, keeping the opening degree of the expansion valve;
if Td1 is larger than or equal to Tm1+ k1, the opening degree of the expansion valve is increased;
wherein k1 is a constant greater than 0;
alternatively, the first and second liquid crystal display panels may be,
for each set of heat pump system after starting, adjusting the opening degree of an expansion valve according to the actual condensation temperature Td2 of a condenser and the target condensation temperature Tm2 corresponding to the current baking section:
if Td2 is less than Tm2-k2, reducing the opening degree of the expansion valve;
if Tm2-k2 is more than or equal to Td2 and less than Tm2+ k2, the opening degree of the expansion valve is kept;
if Td2 is more than or equal to Tm2+ k2, the opening degree of the expansion valve is increased;
wherein k2 is a constant greater than 0;
when the dryer group comprises a plurality of sets of heat pump systems, the control method further comprises the following steps:
acquiring the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section;
determining the starting set number of the heat pump system according to the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section;
when the drying unit comprises two sets of heat pump systems, the starting set number of the heat pump systems is determined according to the actual dry bulb temperature in the curing barn and the target dry bulb temperature in the curing barn corresponding to the current curing section, and the method specifically comprises the following steps:
when the actual dry bulb temperature in the curing barn is less than Tg 0-delta Tg, starting two sets of heat pump systems;
when Tg 0-delta Tg is less than or equal to actual dry bulb temperature in the curing barn < Tg0-k3 x delta Tg, starting one set of heat pump system;
when Tg0-k3 × Δ Tg is less than or equal to the actual dry bulb temperature in the baking room and less than Tg0+ k3 × Δ Tg, the start-stop state of the two sets of heat pump systems is maintained;
when the actual dry bulb temperature in the curing barn is more than or equal to Tg0+ k3 × Δ Tg, both the two sets of heat pump systems are stopped;
wherein, the first and the second end of the pipe are connected with each other,
tg0 is the target dry bulb temperature in the curing barn corresponding to the current curing section;
the delta Tg is the return difference of the temperature control precision of the target dry ball in the curing barn corresponding to the current curing section;
k3 is a constant, and k3 is more than 0 and less than 1;
the target exhaust temperature Tm1= Tg0+ T1 corresponding to the current baking section;
wherein Tg0 is the target dry bulb temperature in the curing barn corresponding to the current curing section; t1 is a preset superheat threshold value;
the target condensation temperature Tm2= Tg0+ T2 corresponding to the current roasting section;
wherein T2 is a preset superheat degree threshold value; t2 is less than T1;
k1= k2, and the value ranges of k1 and k2 are 1.5-2.5;
reducing the opening degree of the expansion valve at a set speed while reducing the opening degree of the expansion valve;
increasing the opening degree of the expansion valve at a set speed when increasing the opening degree of the expansion valve;
when the compressor is in a standby state and is not started, the opening degree of the expansion valve is a set standby opening degree;
when the compressor is started within a set time, the opening degree of the expansion valve is a reference opening degree corresponding to the current roasting section;
after the compressor is started for a set time, the opening degree of the expansion valve is adjusted according to the actual exhaust temperature Td1 of the compressor and the target exhaust temperature Tm1 corresponding to the current roasting section, or the opening degree of the expansion valve is adjusted according to the actual condensation temperature Td2 of the condenser and the target condensation temperature Tm2 corresponding to the current roasting section.
2. The control method according to claim 1, characterized in that: k3=0.5.
3. A readable storage medium, characterized by: the readable storage medium has a readable program stored therein, which when executed implements the dryer group control method of any one of claims 1 to 2.
4. The utility model provides a drying unit which characterized in that: the method comprises the following steps:
each set of heat pump system comprises a compressor, a condenser, an expansion valve and an evaporator;
a readable storage medium storing a readable program;
a controller executing the readable program to implement the dryer group control method according to any one of claims 1 to 2.
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| CN202110980463.9A CN113854612B (en) | 2021-08-25 | 2021-08-25 | Drying unit control method, readable storage medium and drying unit |
| PCT/CN2022/096747 WO2023024635A1 (en) | 2021-08-25 | 2022-06-02 | Drying unit control method, readable storage medium, and drying unit |
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| CN113854612B (en) * | 2021-08-25 | 2023-02-28 | 青岛海尔空调电子有限公司 | Drying unit control method, readable storage medium and drying unit |
| CN114440572B (en) * | 2022-02-14 | 2023-02-17 | 珠海格力电器股份有限公司 | Control method of heat pump drying unit for tobacco drying and heat pump drying unit |
| CN115435585A (en) * | 2022-09-07 | 2022-12-06 | 青岛海尔空调器有限总公司 | Control device and method for heat pump dryer |
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| CN113854612A (en) | 2021-12-31 |
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