WO2020087262A1

WO2020087262A1 - Heat pump control system for dehumidification and drying

Info

Publication number: WO2020087262A1
Application number: PCT/CN2018/112623
Authority: WO
Inventors: 王天舒; 王玉军; 吴小网; 李�柱; 刘军; 王颖
Original assignee: 江苏天舒电器有限公司
Priority date: 2018-10-29
Filing date: 2018-10-30
Publication date: 2020-05-07
Also published as: CN109237925B; CN109237925A

Abstract

A heat pump control system for dehumidification and drying, which is formed with a control that may be switched between a baking mode and a dehumidification mode according to product process requirements. The baking mode is composed of a first heating unit and an air supply unit; the dehumidification mode is composed of a second heating unit, the air supply unit and a return air dehumidification unit; the first heating unit and the second heating unit are arranged in parallel; the supply air unit and the return air dehumidification unit form a closed circulation air path; and a system control in response to current product process requirements is established by means of forming selection control between the modes and process control in respective modes.

Description

Heat pump control system for dehumidification and drying

Technical field

The invention belongs to the field of hot air drying, in particular to a heat pump control system for dehumidification and drying.

Background technique

At present, there are more and more places that need hot air drying in the market, such as tobacco drying, grain drying, medicinal materials drying, fruit and vegetable drying, etc. The drying is mainly performed by coal stove, gas stove, electric stove. Coal and gas are non-renewable strategic energy sources, not the direction of national promotion. Electric furnaces are not suitable for mass promotion because of their high energy consumption and high operating costs. Due to the many reasons mentioned above, heat pump dryers are now gradually being accepted by the market due to many advantages such as energy saving, environmental protection and high drying quality. At present, there are two main types of drying heat pumps on the market. One is hot air dehumidification drying. This drying method is suitable for places where fast water output and high drying temperature are required. The other is dehumidification drying. It is suitable for places with low drying water rate and low drying temperature.

However, because the process of drying various materials varies greatly, and at the same time, during the drying process, the temperature of the dry and wet bulbs in the air is different at different times, so the products are all customized products and cannot be formed. Batch.

The application for the invention number 201711386808.8 discloses a control system and control method for a heat pump dryer, including a heat pump dehumidifier, a drying room, and a temperature sensor, a humidity sensor, a signal receiving module, and a touch screen provided in the heat pump dryer The module, the contactor module and the PLC module that controls the operation of the heat pump dehumidification equipment; the PLC module is electrically connected to the contactor module, the signal receiving module and the touch screen module, and the touch screen module is electrically connected to the temperature sensor and the humidity sensor; The heater module is electrically connected, the temperature sensor is set in the heat pump dryer and the drying room, and the humidity sensor is set in the heat pump dryer.

The application for the invention number 201610094280.6 discloses a drying dehumidifier, including a compressor, an indoor condenser, an outdoor evaporator, a first throttle valve, an outdoor heat exchanger, and a control system. The dehumidification circulation pipeline and the low-temperature dehumidification circulation pipeline, the controller controls the refrigerant to circulate in the corresponding circulation pipeline, and can carry out heating and dehumidification or cooling and dehumidification of the material, thereby overcoming the drying and dehumidification heat pump unit in the prior art which only has heating and dehumidification Mode, and the defect of low temperature dehumidification cannot be performed on the material.

The application for the invention number 201410492849.5 discloses a heat pump dryer with a dehumidification function. Its structure is characterized in that the compressor is connected to a four-way reversing valve, the four-way reversing valve is connected to a fin condenser, and the fin condenser is connected Reservoir, the reservoir is connected to the drying filter, the drying filter is connected to the two-way expansion valve, the two-way expansion valve is connected to the drying filter, the drying filter is connected to the evaporator, the evaporator is connected to the four-way directional valve, and the four-way directional valve is connected The gas-liquid separator, the gas-liquid separator is connected to the compressor, in addition, the outdoor fan is connected to the evaporator, and the indoor fan is connected to the evaporator and the fin condenser.

The invention application with application number 201610100353.8 discloses a heat recovery dehumidification type heat pump dryer, which is composed of a fan, an air-air total heat exchanger, a heat pump system and an electric air valve. The heat pump system includes a refrigeration compressor, an indoor evaporator, an outdoor evaporator, a condenser, and an expansion valve. The indoor high-humidity air and the low-temperature and low-humidity airflow passing through the indoor evaporator are fully heat-exchanged through the air-air total heat exchanger, and the saturated air after pre-cooling and dehumidification passes through the evaporator to further dehumidify the air. When the condenser heats up, the relative humidity is further reduced. When the indoor air moisture content is reduced to a certain level, the efficiency of freezing and dehumidification is reduced and the temperature is affected. At this time, the indoor air passes through the air-air total heat exchanger and the indoor evaporator. Directly through the condenser to further heat up, the relative humidity is further reduced, and then sent into the room by the fan.

Summary of the invention

In order to solve the above problems, the present invention provides a heat pump control system for dehumidification and drying. The technical solutions are as follows:

A heat pump control system for dehumidification and drying, characterized in that a control that can be switched between a baking mode and a dehumidification mode according to product process requirements is formed in the control system to respond to different temperature and humidity in the drying room Working condition demand,

The baking mode is composed of a first heating unit and an air supply unit;

The dehumidification mode is composed of a second heating unit, an air supply unit, and a return air dehumidification unit;

among them,

The first heating unit and the second heating unit are arranged in parallel;

The air supply unit and the return air dehumidification unit form a closed circulation air path;

The control system establishes a system control that responds to the current product process requirements by forming selective control between modes and process control within each mode.

A heat pump control system for dehumidification and drying according to the present invention is characterized by:

The first heating unit and the second heating unit are arranged in parallel in a form that can be adjusted proportionally.

The dehumidification mode establishes a graded dehumidification control in the mode according to the return air humidity.

According to the dehumidification drainage volume, a closed-loop adaptive dynamic dehumidification adjustment control system composed of a ratio adjustment between the first heating unit and the second heating unit is established.

The first heating unit in the baking mode is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, an outdoor evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The second heating unit in the dehumidification mode is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, a return air evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The air supply unit is composed of a return air evaporator, a supply air heating condenser, a supply air fan, and a drying room connected in sequence to the pipeline;

The return air dehumidification unit is composed of a drying room, a first initial effect filter, and a return air evaporator connected in sequence to the pipeline;

The closed circulation air path is formed by the connection of the air supply unit and the return air dehumidification unit.

The first heating unit is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, an outdoor evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The second heating unit is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, a return air evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

A water collecting tray is provided at the lower end of the return air evaporator, and a flowmeter is provided at the drain of the water collecting tray.

The main electronic expansion valve is installed on the refrigerant pipeline leading from the accumulator to the outdoor evaporator,

Auxiliary electronic expansion valve is provided on the refrigerant pipeline leading from the accumulator to the return air evaporator,

The auxiliary electronic expansion valve adjusts the opening degree according to the requirements of the process dehumidification water volume,

According to the time sequence, compare the current value of the flowmeter with the value set by the process, and establish the feedback opening adjustment of the main electronic expansion valve based on the current auxiliary electronic expansion valve opening, forming a cooperation between the main electronic expansion valve and the auxiliary electronic expansion valve. Adaptive feedback dehumidification adjustment, thereby forming an adaptation of the actual dehumidification water volume and the set dehumidification water volume.

The auxiliary electronic expansion valve establishes a step-by-step gradient adjustment according to the requirements of process dehumidification water volume;

Under the current gradient corresponding to the step-by-step gradient adjustment, after the unit is turned on, set the collection points at equal time intervals and collect real-time data statistics of the flowmeter according to the collection points;

Compare the statistical data collected in real time with the set value under this gradient, and adjust the opening of the main electronic expansion valve according to the comparison result, to form the statistical data collected in real time and continuously track the dynamic correction adjustment control of the set value under this gradient .

According to the return air humidity, the dehumidification mode establishes the following three levels of dehumidification control in the mode,

Ⅰ. First-level dehumidification with low humidity;

Ⅱ. High humidity fresh air mixed secondary dehumidification;

Ⅲ. High humidity fresh air mixed temperature control type three-level dehumidification.

A humidity sensor is arranged on the ventilation pipeline leading from the first primary effect filter to the return air evaporator,

There is a three-way member between the first primary effect filter and the return air evaporator,

The first end pipeline of the three-way member is connected to the air outlet of the first primary effect filter,

The second end pipeline of the three-way member is connected to the air inlet of the return air evaporator,

The third end pipeline of the three-way component is connected to the air inlet of an exhaust fan,

The air outlet pipe of the exhaust fan is connected to the first air inlet of a full heat exchanger,

The second air inlet of the total heat exchanger is the fresh air inlet end,

The first air outlet pipeline of the total heat exchange is connected to the air inlet of the return air evaporator.

There is also a second air outlet on the total heat exchanger,

A heat recovery evaporator is provided at the second air outlet of the total heat exchanger;

An exhaust valve is provided at the air outlet of the heat recovery evaporator,

The heat recovery evaporator is used to receive the gas exchanged with the heat exchange through the second air outlet of the total heat exchanger, and deliver the gas after the heat exchanger to the air inlet of the outdoor evaporator through the air exhaust valve.

A fresh air heating condenser is also arranged between the first air outlet of the total heat exchanger and the air inlet of the return air evaporator;

The fresh air heating condenser is used to heat the mixed air output by the total heat exchanger to respond to the return air temperature requirement that subsequently enters the air inlet of the return air evaporator.

According to the current humidity value detected by the humidity sensor in real time, combined with process requirements, a dehumidification control based on three levels is established;

When the return air humidity is lower than the process setting value, the low-humidity first-level dehumidification is started, and the closed type consisting of a drying room, a first primary effect filter, a return air evaporator, and a supply air heating condenser connected by pipes in sequence Circulation loop, forming a return air dehumidification channel for first-level dehumidification;

When the return air humidity is higher than the process setting value, the high temperature fresh air mixed secondary dehumidification is started. The return air passes through the drying room and reaches the first primary effect filter and is divided into two paths. The first path leads to the return air evaporator , The second way is connected to the total heat exchanger through the exhaust fan pipe, and then connected to the return air evaporator by the total heat exchanger to form a high humidity fresh air hybrid secondary dehumidification dehumidification channel structure;

When the return air humidity is higher than the process setting value, and the temperature after heat exchange through the total heat exchanger is lower than the temperature value required by the process, the high humidity fresh air hybrid temperature controlled three-level dehumidification is started, and the return air passes After the drying room reaches the first primary effect filter, it is divided into two paths, the first path leads to the return air evaporator, the second path is connected to the total heat exchanger through the exhaust fan pipeline, and then the full heat exchanger Connected to the fresh air heating condenser, and finally connected to the return air evaporator through the fresh air heating condenser pipeline, forming a high humidity fresh air hybrid temperature control three-stage dehumidification dehumidification channel structure.

The refrigerant inlet through the heat recovery evaporator enters the heat recovery evaporator refrigerant chamber, and the refrigerant source participating in the heat exchange is provided by two channels; the first channel is transported through the refrigerant outlet of the outdoor evaporator and the second channel is refrigerant Outlet transportation; the cold medium after participating in the heat exchange is connected to the four-way valve through the refrigerant outlet pipe of the heat recovery evaporator.

The fresh air heating condenser is arranged between the air supply heating condenser and the liquid reservoir, and the cold medium discharged through the heat exchange of the air supply heating condenser is used as the refrigerant source for the heat exchange of the fresh air heating condenser, and participates in completing the heat of the fresh air evaporator The exchanged refrigerant is then piped to the reservoir.

The heat pump control system for dehumidification and drying of the present invention,

First, establish an adjustable adaptive control between the dehumidification mode and the baking mode;

Secondly, in the dehumidification mode, further establishment of low-humidity first-level dehumidification, high-humidity fresh air hybrid two-level dehumidification, high-humidity fresh air hybrid temperature-controlled three-level dehumidification based on monitoring of return air humidity, Three levels of dehumidification control to form a fine control response to return air humidity and an adaptive control response to return air temperature;

Thirdly, in the dehumidification mode, an adaptive dynamic dehumidification adjustment control system based on monitoring of the dehumidification displacement is further established. The adaptive dynamic dehumidification adjustment control system controls the temperature between the first heating unit and the second heating unit by Proportional adjustment formation;

Then, using full heat recovery technology, the exhaust hot air and fresh air are recovered for heat to obtain free heat;

In summary, the heat pump control system for dehumidification and drying of the present invention is designed with three evaporators and two condensers, so as to achieve return air dehumidification, fresh air heating, compressor overheating and overheating in the external environment. Free heat is transferred to the drying room to meet the changing working conditions of high and low temperature and high and low humidity in the drying room; among them, the designed two-way flow distribution technology adopts two-way electronic expansion valve throttle control to automatically adjust the distribution of the two-way evaporator The flow rate satisfies the return air drying and wet bulb temperatures of different drying rooms while ensuring the best dehumidification effect; and adopts full heat recovery technology to recover the discharged hot air and fresh air to obtain free heat.

BRIEF DESCRIPTION

1 is a schematic block diagram of the overall structure of the present invention;

Figure 2 is a schematic diagram of the structure of Figure 1;

3 is a schematic diagram of the overall control tree structure of the present invention;

4 is a schematic diagram of the system structure of the present invention.

detailed description

Hereinafter, a heat pump control system for dehumidification and drying of the present invention will be further specifically described based on the drawings and specific embodiments of the specification.

A heat pump control system for dehumidification and drying as shown in Figures 1 and 2 is characterized in that a control that can be switched between the baking mode and the dehumidification mode according to the product process requirements is formed in the control system for Respond to different temperature and humidity conditions in the drying room,

The baking mode is composed of a first heating unit and an air supply unit;

among them,

The first heating unit and the second heating unit are arranged in parallel;

among them,

The first heating unit and the second heating unit are arranged in parallel in a form that can be adjusted proportionally;

Step by step, according to the amount of dehumidification drainage, establish the ratio of the first heating unit and the second heating unit

Closed-loop adaptive dynamic dehumidification adjustment control system.

among them,

According to the time sequence, compare the current value of the flowmeter with the value set by the process, and establish the feedback opening adjustment of the main electronic expansion valve based on the current auxiliary electronic expansion valve opening degree. Adaptive feedback dehumidification adjustment, thereby forming an adaptation of the actual dehumidification water volume and the set dehumidification water volume.

among them,

Compare the statistical data collected in real time with the setting value under this gradient, and adjust the opening of the main electronic expansion valve according to the comparison result, to form the statistical data collected in real time and continuously track the dynamic correction adjustment control under the gradient. .

among them,

Ⅰ. First-level dehumidification with low humidity;

Ⅱ. High humidity fresh air mixed secondary dehumidification;

among them,

The second air inlet of the total heat exchanger is the fresh air inlet end,

among them,

There is also a second air outlet on the total heat exchanger,

An exhaust valve is provided at the air outlet of the heat recovery evaporator,

among them,

Description of working principle

The high-temperature and high-pressure gas refrigerant discharged from the compressor flows into the four-way valve, and then flows into the air supply heating condenser to release heat to the return air of the drying room, and the liquid refrigerant of the air supply heating condenser is discharged, and then enters the fresh air heating condenser The supercooled heat is recovered and flows into the accumulator. The condensate from the accumulator is divided into two channels, one enters the main electronic expansion valve and the other enters the auxiliary electronic expansion valve. The refrigerant section of the main electronic expansion valve After the pressure is reduced, it flows into the outdoor evaporator to absorb heat from the external environment. The refrigerant that enters the auxiliary electronic expansion valve is throttled and depressurized, and then enters the return air evaporator for evaporation and dehumidification. The gaseous refrigerant and the gas from the outdoor evaporator merge together and enter the heat recovery evaporator for superheat recovery, absorbing the exhaust from the drying room. The heat flows into the four-way valve and then to the vapor-liquid separator, and is sucked into the compressor to form a closed circulation system.

After the air returned from the drying room passes through the primary effect filter, the air inlet and air return evaporator dehumidifies, then enters the air supply heating condenser to increase the temperature, and is sent to the drying room by the air supply fan. When it is detected that the return air humidity is higher than the set value, the exhaust fan is turned on, a part of the high humidity return air is extracted and sent to the full heat exchanger, and the fresh air coming in through the fresh air valve is used for full heat exchange, and the fresh air is preheated. Reheat recovery evaporator, after the heat exchanged through the heat recovery evaporator again for heat recovery, it is discharged by the exhaust valve, the discharged air goes to the outdoor evaporator, after the outdoor evaporator absorbs heat, the outdoor cold wind Machine row. After passing through the full heat exchanger, the fresh air and fresh air heating condenser are reheated and mixed with the return air from the drying room. When the exhaust temperature exceeds 105 degrees, the injection solenoid valve opens to reduce the exhaust temperature and ensure the life of the compressor. When the exhaust temperature is below 90 degrees, the injection solenoid valve is closed.

The four operating modes involved in this control system are as follows:

Dehumidification mode:

In this mode, the main electronic expansion valve is in the closed state, and the auxiliary electronic expansion valve is comprehensively processed according to the three values of the return air evaporator temperature, the return air evaporator outlet temperature, and the suction temperature to control the opening of the auxiliary electronic expansion valve.

The specific control process is as follows (T suction superheat = T suction temperature-T return air evaporation temperature):

Return air relative humidity ≥80%, T suction superheat is 2,

80%> Return air relative humidity ≥60%, T suction superheat is 3,

60%> Return air relative humidity ≥ 45%, T suction superheat is 4,

45%> Return air relative humidity ≥ 25%, T suction superheat is 5,

The relative humidity of the return air is less than 25%, and the T suction superheat is 7.

When T return air dew point temperature-T return air evaporation temperature ≥ 4, the value of T suction superheat is -1.

When 2≤T return air dew point temperature-T return air evaporation temperature <4, the value of T suction superheat remains unchanged.

When T return air dew point temperature-T return air evaporation temperature <4, the value of T suction superheat remains unchanged.

It will inspect once every 5 minutes and revise the value of T suction superheat.

Baking mode:

In this mode, the main electronic expansion valve is opened, and the auxiliary electronic expansion valve is closed. According to the three values of outdoor evaporator temperature, outdoor evaporator outlet temperature, and suction temperature, comprehensive processing is performed to control the opening degree of the main electronic expansion degree.

The specific control process is as follows (T suction superheat 1 = T suction temperature-T outdoor evaporation temperature):

Relative humidity of return air ≥80%, T suction superheat 1 is 2,

80%> Return air relative humidity ≥ 60%, T suction superheat 1 is 3,

60%> Return air relative humidity ≥ 45%, T suction superheat 1 is 4,

45%> Return air relative humidity ≥ 25%, T suction superheat 1 is 5,

The relative humidity of the return air is less than 25%, and the T suction superheat 1 is 7.

When T return air dew point temperature-T return air evaporation temperature ≥ 4, the value of T suction superheat 1 is -1.

When 2≤T return air dew point temperature-T return air evaporation temperature <4, the value of T suction superheat 1 remains unchanged.

When T return air dew point temperature-T return air evaporation temperature <4, the value of T suction superheat 1 remains unchanged.

It is inspected once every 5 minutes, and the value of T inspiratory superheat 1 is corrected.

Automatic adaptation mode:

In this mode, according to the drying characteristics of each stage, the dehumidification water volume (G1-G10) is designed in ten stages. A water collecting tray is placed under the return air evaporator, and a flow meter is installed on the drain to measure the water volume during dehumidification . The auxiliary electronic expansion valve is opened to the initial opening degree, and the main electronic expansion valve is closed. At this time, the auxiliary electronic expansion valve is automatically adjusted according to the logic of the auxiliary electronic expansion valve in the dehumidification mode. After the unit is opened for ten minutes, the drainage flow meter is turned on to count the water volume for ten minutes and the water volume designed at this stage. If the dehumidification water volume is lower than the designed Water volume, keep running in this state. If the amount of dehumidified water is higher than the designed amount of water, the main electronic expansion valve is adjusted to the minimum opening, and part of the liquid refrigerant out of the reservoir is distributed to the outdoor evaporator. The flow into the return air evaporator will be reduced. At this time, the moisture dehumidified by the return air evaporator will gradually decrease, and the opening of the main electronic expansion valve will gradually increase until it reaches the designed water volume at this stage. Through the main and auxiliary expansion valves, the two-way flow rate is constantly corrected to achieve the actual dehumidification water volume to meet the designed dehumidification volume requirements, and at the same time to meet the return air dry bulb temperature requirements.

Note 1: The initial opening and operation of the auxiliary electronic expansion valve are as follows:

1. Initial opening = 230 + 3.5 * outlet temperature-opening coefficient * (20-return air temperature)

In the above formula, when the return air temperature is <20 degrees, the opening coefficient = 2; when the return air temperature is ≥ 20 degrees, the opening coefficient = 20. If the initial opening calculation value is> 480 steps, it is calculated as 480.

2. When the difference between the suction temperature and the return air evaporator temperature is greater than 8 degrees, adjust 4 * 8 steps each time.

3. When the difference between the suction temperature and the return air evaporator temperature is greater than 2 degrees, adjust 2 * 8 steps each time.

4. When the difference between the suction temperature and the return air evaporator temperature is greater than 1 degree and less than 2 degrees, adjust 1 * 8 steps each time.

Note 2: The initial opening and operation of the main electronic expansion valve are as follows:

1. Initial opening = 230 + 3.5 * outlet temperature-opening coefficient * (20-outdoor ambient temperature)

2. When the difference between the suction temperature and the outdoor evaporator temperature is greater than 8 degrees, adjust 4 * 8 steps each time.

3. When the difference between the suction temperature and the outdoor evaporator temperature is greater than 2 degrees, adjust 2 * 8 steps each time.

4. When the difference between the suction temperature and the outdoor evaporator temperature is greater than 1 degree and less than 2 degrees, adjust 1 * 8 steps each time.

Ventilation mode: At this time, the compressor is turned off, only the blower fan is turned on, and the air system is circulated.

Example 1

The control system in this embodiment provides the product to switch between three modes of baking mode, dehumidification mode and ventilation mode;

The closed refrigerant heat exchange circuit that constitutes the baking mode is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, an outdoor evaporator, a four-way valve, and a vapor-liquid separator connected in sequence.

The closed refrigerant heat exchange circuit constituting the dehumidification mode is composed of a compressor, a four-way valve, an air supply heating condenser, an accumulator, a return air evaporator, a four-way valve, and a vapor-liquid separator connected in sequence.

The hot air supply channel constituting the baking mode or dehumidification mode is composed of a supply air heating condenser, an air supply fan and a drying room connected in sequence to the pipeline.

Set the return air setting after the air supply to cooperate with the air supply channel to form a closed circulation air duct; the return air setting is composed of a drying room connected by pipelines, the first primary effect filter, the return air evaporator and the supply air Composed of wind-heated condenser.

In the baking mode, the main electronic expansion valve is opened, and the auxiliary electronic expansion valve is closed. According to the three values of outdoor evaporator temperature, outdoor evaporator outlet temperature, and suction temperature, comprehensive processing is performed to control the opening degree of the main electronic expansion.

In the dehumidification mode, the main electronic expansion valve is in the closed state, and the auxiliary electronic expansion valve is comprehensively processed according to the three values of the return air evaporator temperature, the return air evaporator outlet temperature, and the suction temperature to control the opening of the auxiliary electronic expansion valve.

In the ventilation mode, the compressor is turned off at this time, only the blower fan is turned on, and the air system is circulated.

Example 2

The control in this embodiment is based on the dehumidification mode, and further establishes three levels of dehumidification control in the dehumidification mode according to the return air humidity, namely: Ⅰ. Low humidity first-level dehumidification; Ⅱ. High humidity fresh air Mixed two-stage dehumidification; Ⅲ. High humidity fresh air mixed temperature-controlled three-stage dehumidification.

Example 3

The control in this embodiment is based on the dehumidification mode, and further establishes a closed-loop adaptive dynamic dehumidification adjustment control system based on the baking mode and the dehumidification mode according to the dehumidification drainage volume;

The baking mode is composed of a first heating unit and an air supply unit;

Establish a closed-loop adaptive dynamic dehumidification adjustment control system composed of the ratio adjustment between the first heating unit and the second heating unit according to the dehumidification drainage volume;

Under the current gradient corresponding to the step-by-step gradient adjustment, after the unit is turned on, set the acquisition point at equal intervals (in this example, it is set every ten minutes), and perform real-time data on the flowmeter according to the acquisition point Statistics collection;

Example 4

In this embodiment, on the basis of Embodiment 2, a heat recovery evaporator is further provided at the rear end of the total heat exchanger, and the heat recovery evaporator is used to recover the heat after the total heat exchange and then send it to the outdoor evaporator. In order to achieve free heat recovery and utilization.

In the above embodiments, a liquid ejection capillary is provided on the pipeline leading from the four-way valve to the vapor-liquid separator, the liquid ejection capillary leads to the reservoir, and a liquid ejection solenoid valve is provided on the liquid ejection capillary; When the final exhaust temperature in the system exceeds 105 degrees, the injection solenoid valve opens to reduce the exhaust temperature and ensure the life of the compressor. When the exhaust temperature is below 90 degrees, the injection solenoid valve is closed.

The system configuration of the above embodiment is described as follows:

1. Total heat exchanger, this heat exchange capacity is designed according to 30% of the cooling capacity of the compressor under standard operating conditions, the design operating conditions are fresh air inlet temperature of 15 degrees, exhaust air temperature of 40 degrees, and exhaust air volume is the air volume of the blower 30%.

2. The heat exchange capacity of the outdoor evaporator is configured according to the compressor's capacity 100%, the return air evaporator is configured according to the compressor's capacity 25%, and the heat recovery evaporator is configured according to the compressor's capacity 15%.

3. The air inlet heating condenser is configured according to the compressor's capacity 100%, and the fresh air heating condenser is configured according to the compressor's capacity 25%.

4. The main electronic expansion valve is configured at 125% of the compressor capacity, and the auxiliary electronic expansion valve is configured at 20% of the compressor capacity.

5. When the exhaust temperature exceeds 105 degrees, the injection solenoid valve is opened to reduce the exhaust temperature to ensure the life of the compressor. When the exhaust temperature is less than 90 degrees, close the injection solenoid valve.

Claims

A heat pump control system for dehumidification and drying, characterized in that a control that can be switched between a baking mode and a dehumidification mode according to product process requirements is formed in the control system to respond to different temperature and humidity in the drying room Working condition demand,

The baking mode is composed of a first heating unit and an air supply unit;

The dehumidification mode is composed of a second heating unit, an air supply unit, and a return air dehumidification unit;

among them,

The first heating unit and the second heating unit are arranged in parallel;

The air supply unit and the return air dehumidification unit form a closed circulation air path;

The control system establishes a system control that responds to the current product process requirements by forming selective control between modes and process control within each mode.
The heat pump control system for dehumidification and drying according to claim 1, characterized in that:

The first heating unit and the second heating unit are arranged in parallel in a form that can be adjusted proportionally.
The heat pump control system for dehumidification and drying according to claim 1, characterized in that:

The dehumidification mode establishes a graded dehumidification control in the mode according to the return air humidity.
The heat pump control system for dehumidification and drying according to claim 2, characterized in that:

According to the dehumidification drainage volume, a closed-loop adaptive dynamic dehumidification adjustment control system composed of a ratio adjustment between the first heating unit and the second heating unit is established.
The heat pump control system for dehumidification and drying according to claim 1, characterized in that:

The first heating unit in the baking mode is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, an outdoor evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The second heating unit in the dehumidification mode is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, a return air evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The air supply unit is composed of a return air evaporator, a supply air heating condenser, a supply air fan, and a drying room connected in sequence to the pipeline;

The return air dehumidification unit is composed of a drying room, a first initial effect filter, and a return air evaporator connected in sequence to the pipeline;

The closed circulation air path is formed by the connection of the air supply unit and the return air dehumidification unit.
The heat pump control system for dehumidification and drying according to claim 2 or 4, wherein:

The first heating unit is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, an outdoor evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

The second heating unit is composed of a compressor, a four-way valve, an air supply heating condenser, a liquid reservoir, a return air evaporator, a four-way valve, and a vapor-liquid separator connected in sequence;

A water collecting tray is provided at the lower end of the return air evaporator, and a flowmeter is provided at the drain of the water collecting tray.

The main electronic expansion valve is installed on the refrigerant pipeline leading from the accumulator to the outdoor evaporator,

Auxiliary electronic expansion valve is provided on the refrigerant pipeline leading from the accumulator to the return air evaporator,

The auxiliary electronic expansion valve adjusts the opening degree according to the requirements of the process dehumidification water volume,

According to the time sequence, compare the current value of the flowmeter with the value set by the process, and establish the feedback opening adjustment of the main electronic expansion valve based on the current auxiliary electronic expansion valve opening, forming a cooperation between the main electronic expansion valve and the auxiliary electronic expansion valve. Adaptive feedback dehumidification adjustment, thereby forming an adaptation of the actual dehumidification water volume and the set dehumidification water volume.
The heat pump control system for dehumidification and drying according to claim 6, characterized in that:

The auxiliary electronic expansion valve establishes a step-by-step gradient adjustment according to the requirements of process dehumidification water volume;

Under the current gradient corresponding to the step-by-step gradient adjustment, after the unit is turned on, set the collection points at equal time intervals and collect real-time data statistics of the flowmeter according to the collection points;

Compare the statistical data collected in real time with the setting value under this gradient, and adjust the opening of the main electronic expansion valve according to the comparison result, to form the statistical data collected in real time and continuously track the dynamic correction adjustment control under the gradient. .
The heat pump control system for dehumidification and drying according to claim 3, characterized in that:

According to the return air humidity, the dehumidification mode establishes the following three levels of dehumidification control in the mode,

Ⅰ. First-level dehumidification with low humidity;

Ⅱ. High humidity fresh air mixed secondary dehumidification;

Ⅲ. High humidity fresh air mixed temperature control type three-level dehumidification.
A heat pump control system for dehumidification and drying according to claims 5 and 8, characterized in that:

A humidity sensor is arranged on the ventilation pipeline leading from the first primary effect filter to the return air evaporator,

There is a three-way member between the first primary effect filter and the return air evaporator,

The first end pipeline of the three-way member is connected to the air outlet of the first primary effect filter,

The second end pipeline of the three-way member is connected to the air inlet of the return air evaporator,

The third end pipeline of the three-way component is connected to the air inlet of an exhaust fan,

The air outlet pipe of the exhaust fan is connected to the first air inlet of a full heat exchanger,

The second air inlet of the total heat exchanger is the fresh air inlet end,

The first air outlet pipeline of the total heat exchange is connected to the air inlet of the return air evaporator.
The heat pump control system for dehumidification and drying according to claim 9, characterized in that:

There is also a second air outlet on the total heat exchanger,

A heat recovery evaporator is provided at the second air outlet of the total heat exchanger;

An exhaust valve is provided at the air outlet of the heat recovery evaporator,

The heat recovery evaporator is used to receive the gas exchanged with the heat exchange through the second air outlet of the total heat exchanger, and deliver the gas after the heat exchanger to the air inlet of the outdoor evaporator through the air exhaust valve.
The heat pump control system for dehumidification and drying according to claim 9, characterized in that:

A fresh air heating condenser is also arranged between the first air outlet of the total heat exchanger and the air inlet of the return air evaporator;

The fresh air heating condenser is used to heat the mixed air output by the total heat exchanger to respond to the return air temperature requirement that subsequently enters the air inlet of the return air evaporator.
The heat pump control system for dehumidification and drying according to claim 9, characterized in that:

According to the current humidity value detected by the humidity sensor in real time, combined with process requirements, a dehumidification control based on three levels is established;

When the return air humidity is lower than the process setting value, the low-humidity first-level dehumidification is started, and the closed type consisting of a drying room, a first primary effect filter, a return air evaporator, and a supply air heating condenser connected by pipes in sequence Circulation loop, forming a return air dehumidification channel for first-level dehumidification;

When the return air humidity is higher than the process setting value, the high temperature fresh air mixed secondary dehumidification is started. The return air passes through the drying room and reaches the first primary effect filter and is divided into two paths. The first path leads to the return air evaporator , The second way is connected to the total heat exchanger through the exhaust fan pipe, and then connected to the return air evaporator by the total heat exchanger to form a high humidity fresh air hybrid secondary dehumidification dehumidification channel structure;

When the return air humidity is higher than the process setting value, and the temperature after heat exchange through the total heat exchanger is lower than the temperature value required by the process, the high humidity fresh air hybrid temperature controlled three-level dehumidification is started, and the return air passes After the drying room reaches the first primary effect filter, it is divided into two paths, the first path leads to the return air evaporator, the second path is connected to the total heat exchanger through the exhaust fan pipeline, and then the full heat exchanger Connected to the fresh air heating condenser, and finally connected to the return air evaporator through the fresh air heating condenser pipeline, forming a high humidity fresh air hybrid temperature control three-stage dehumidification dehumidification channel structure.
The heat pump control system for dehumidification and drying according to claim 10, characterized in that:

The refrigerant inlet through the heat recovery evaporator enters the heat recovery evaporator refrigerant chamber, and the refrigerant source participating in the heat exchange is provided by two channels; the first channel is transported through the refrigerant outlet of the outdoor evaporator and the second channel is refrigerant Outlet transportation; the cold medium after participating in the heat exchange is connected to the four-way valve through the refrigerant outlet pipe of the heat recovery evaporator.
The heat pump control system for dehumidification and drying according to claim 11, characterized in that:

The fresh air heating condenser is arranged between the air supply heating condenser and the liquid reservoir, and the cold medium discharged through the heat exchange of the air supply heating condenser is used as the refrigerant source for the heat exchange of the fresh air heating condenser, and participates in completing the heat of the fresh air evaporator The exchanged refrigerant is then piped to the reservoir.