CN115211313A

CN115211313A - Seedbed temperature control system and control method thereof

Info

Publication number: CN115211313A
Application number: CN202210816513.4A
Authority: CN
Inventors: 邓晨冕; 张�杰; 邱跃; 王冰军; 周炀
Original assignee: Ningbo Haizhipu Intelligent Technology Co ltd
Current assignee: Ningbo Haizhipu Intelligent Technology Co ltd
Priority date: 2022-07-12
Filing date: 2022-07-12
Publication date: 2022-10-21

Abstract

The invention provides a seedbed temperature control system and a control method thereof. Directly set up the heat transfer capillary on the seedbed, set up insulation construction again on the seedbed, just can realize local accuse temperature to the multilayer is arranged, realizes high density and grows seedlings, saves space, directly heats and cools down the seedling root system on the seedbed simultaneously, all has the seedbed above the district of growing seedlings in addition, that is to say the district of growing seedlings both can heat and cool down above and below. Meanwhile, the scheme in the application is a heat pump system, air blowing cannot be generated, the heating/refrigerating effect is good, the temperature field distribution is uniform, and the equipment investment is low. Preventing the seedlings from being affected. The control method of the seedbed temperature control system directly realizes the switching between cooling and heating through the switching of the four-way reversing valve.

Description

Seedbed temperature control system and control method thereof

Technical Field

The invention relates to the field of agricultural seedling culture and cultivation, in particular to a seedbed temperature control system and a control method thereof.

Background

Temperature is one of the key factors influencing the growth of crops, influences the development speed of the crops, and further influences the growth period of the crops, the development period and the growth period. Some crops must be subjected to certain temperature conditions during the raising of seedlings, and the optimum temperature during the day and night is different for different crops, so that controlling the temperature of raising crops is of great importance for the production rate of crops.

In the prior art, crop greenhouses are mostly heated by burning coal, formaldehyde and the like, and the mode generates a large amount of harmful gases such as CO, CO2, SO2 and the like, SO that the environment is not protected, and the effect is not good. Later appearing electric floor heating is used for heating warmhouse booth, and the effect is still good, but can only realize rising temperature, still needs the installation air conditioning equipment in addition to carry out the cooling treatment, and power consumption is big moreover, and easy electric leakage, the security performance is poor. Air conditioning equipment has strong blowing sense, and cannot be applied to the seedling raising of crops with special requirements, so that the seedling raising effect is influenced.

With the development and popularization and application of heat pump technology, water/ground source heat pumps are used for planting greenhouse crops, but all the heat pumps use water as a heat exchange medium, so that the heat loss caused by secondary heat exchange is large, and in addition, water leakage and pipeline freezing damage in winter exist. The space of crops greenhouse, big-arch shelter is generally great, and is highly higher for the heating of last conventionality or cooling mode carry out temperature control to the greenhouse and handle, and what heat is the air, hardly heats plant roots, and in addition, the energy consumption is very big, and equipment investment is also very high, and heating or cooling effect are also not good. In addition, for the crop seedling raising in a high space, the seedling raising beds are generally arranged in a multilayer mode in the vertical direction, and the problem that local temperature is too high or too low due to the fact that the uniformity of the temperature in the greenhouse cannot be guaranteed for the high-density planting heat pump system is solved.

Disclosure of Invention

The invention aims to provide a seedbed temperature control system capable of saving energy consumption, and the invention also aims to provide a control method of the seedbed temperature control system, and accurate temperature control of crop seedlings.

The utility model provides a seedbed temperature control system, includes heat pump unit and is used for arranging the seedbed of seedling, the seedbed is provided with the multilayer and follows vertical interval arrangement, and adjacent upper and lower two-layer the region between the seedbed constitutes the district of growing seedlings, the seedbed upper berth is equipped with the heat transfer capillary, the heat transfer capillary is carried out heat transfer control by heat pump unit.

Among the above-mentioned scheme, directly set up the heat transfer capillary on the seedbed, set up insulation construction again on the seedbed, just can realize local accuse temperature to the multilayer is arranged, realizes that high density is grown seedlings, saves space, directly heats and cools down the seedling root system on the seedbed simultaneously, all has the seedbed above the district of growing seedlings in addition, that is to say the district of growing seedlings about the homoenergetic heats and cools down. Meanwhile, the scheme in the application is a heat pump system, air blowing cannot be generated, the heating/refrigerating effect is good, the temperature field distribution is uniform, and the equipment investment is low. Preventing the seedlings from being affected. The control method of the seedbed temperature control system directly realizes the switching between cooling and heating through the switching of the four-way reversing valve.

Preferably, the heat pump unit comprises a compressor, a liquid outlet of the compressor is sequentially connected with an oil separator and a four-way reversing valve through a pipeline, and the four-way reversing valve comprises a port C, a port E, a port S and a port D communicated with the oil separator;

the C port is sequentially connected with an outdoor finned heat exchanger, a main circuit electronic expansion valve, a high-pressure liquid storage device and a liquid pipe stop valve through pipelines, the heat exchange capillary pipe comprises a tail end liquid pipe and a tail end gas pipe, the liquid pipe stop valve is connected with the tail end liquid pipes on the plurality of heat exchange capillary pipes through a branch pipe, and the capillary electronic expansion valve is arranged on the pipeline between the heat exchange capillary pipe and the branch pipe;

the E port is connected with an air pipe stop valve through a pipeline, and the air pipe stop valve is connected with tail end air pipes on the plurality of heat exchange capillary pipes through flow dividing pipes;

the S port is connected with a gas-liquid separator through a pipeline, and an air suction pipe communicated with a compressor is arranged at an outlet of the gas-liquid separator.

Preferably, an exhaust temperature sensor is arranged on a pipeline between the compressor and the oil separator, a high-pressure switch and a high-pressure sensor are arranged on a pipeline between the oil separator and the four-way reversing valve, a tail end liquid pipe temperature sensor is arranged at the tail end liquid pipe, a tail end air pipe temperature sensor and an electromagnetic valve are arranged at the tail end air pipe, and a seedbed environment temperature sensor is arranged on the seedbed.

Preferably, the air suction pipe is provided with an air suction temperature sensor, a low pressure sensor and a low pressure switch, an oil return capillary tube is connected between the oil separator and the air suction pipe, and a connecting end of the oil return capillary tube is positioned between the air suction temperature sensor and the low pressure sensor.

A control method of a seedbed temperature control system comprises the following steps:

s1, monitoring and obtaining a seedbed environment temperature Tai in real time through a seedbed environment temperature sensor, and presetting a user heating temperature value Tset1, a user refrigerating temperature value Tset2 and an environment temperature deviation value T7;

s2, when the seedbed environment temperature Tai is smaller than Tset1, starting a heating mode by the system, starting a compressor, controlling a four-way reversing valve to act, communicating a port D with a port E, communicating a port C with a port S, and enabling a medium in the compressor to flow along the following route:

compressor-oil separator-D port-E port-air pipe stop valve-shunt tube-solenoid valve-end air pipe-heat exchange capillary tube-end liquid pipe-capillary tube electronic expansion valve-branch pipe-liquid pipe stop valve-high pressure reservoir-main circuit electronic expansion valve-outdoor fin heat exchanger-C port-S port-gas-liquid separator-air suction pipe-compressor;

when the seedbed ambient temperature Tai is larger than Tset2, the system starts a refrigeration mode, starts a compressor, controls a four-way reversing valve to act, enables a port D to be communicated with a port C, enables a port E to be communicated with a port S, and enables a medium in the compressor to flow along the following route:

compressor-oil separator-D port-C port-outdoor finned heat exchanger-main circuit electronic expansion valve-high pressure reservoir-liquid pipe stop valve-manifold-capillary electronic expansion valve-end liquid pipe-heat exchange capillary pipe-end air pipe-solenoid valve-shunt pipe-air pipe stop valve-E port-S port-gas-liquid separator-air suction pipe-compressor;

s3, in the heating process, when the ambient temperature Tai of the seedbed is more than Tset1+ T7, stopping the compressor;

in the refrigeration process, when the ambient temperature Tai of the seedbed is less than Tset2-T7, the compressor is stopped.

In the scheme, the refrigeration and heating switching is directly realized through the switching of the four-way reversing valve, so that the refrigeration and heating can be realized without two systems, and the system equipment is reduced.

Preferably, a temperature intermediate value Tset of the seedbed, a preset value T1 of temperature range deviation and a preset value delta T of unit time change rate are preset;

in the heating process, the average temperature of the seedbed is obtained by calculation

When in use

When the frequency of the compressor is increased, the frequency of the compressor is increased; when in use

And the change rate of the average ambient temperature of the seedbed in unit time after the system is started

When so, maintaining the current compressor frequency; when in use

The compressor frequency is controlled by down-conversion, wherein

For the calculated average temperature of the startup seedbed in the period,

calculating the average temperature of the starting seedbed in the last period, wherein t is the frequency regulation period of the compressor;

in the process of refrigeration, when

When so, maintaining the current compressor frequency; when in use

And in time, the frequency of the compressor is subjected to frequency reduction control.

Preferably, the air suction temperature sensor acquires air suction temperature Ts in real time, the low-pressure sensor acquires low pressure in real time, a pressure-saturation temperature comparison table is inquired to acquire saturation temperature Ps _ T corresponding to the low pressure, air suction superheat SH1= Ts-Ps _ T of a temperature control system is defined, and deviation range values of the air suction superheat are preset to be T2 and T3 and an air suction superheat intermediate value SH1_ tar;

in the refrigeration process, the main electronic expansion valve keeps the maximum opening degree;

in the heating process, when SH1 is less than or equal to SH1_ tar-T2, the main-path electronic expansion valve performs valve closing adjustment; when SH1 is more than or equal to SH1_ tar + T3, the main-path electronic expansion valve performs valve opening large adjustment; when SH1_ tar-T2 is less than SH1 and less than SH1_ tar + T3, the main electronic expansion valve keeps the current valve opening.

Preferably, the exhaust temperature sensor acquires exhaust temperature Td in real time, the high pressure sensor acquires high pressure in real time, a pressure-saturation temperature comparison table is inquired to acquire saturation temperature Pd _ t corresponding to the high pressure, exhaust superheat Td _ SH = Td-Pd _ t of the temperature control system is defined, and an exhaust superheat lower limit value Td _ SH1 and an exhaust superheat upper limit value Td _ SH2 are set;

when Td _ SH is less than or equal to Td _ SH1, the main electronic expansion valve takes the Td _ SH value as the standard, no matter how the SH1 value is adjusted in a small mode, when Td _ SH is more than or equal to Td _ SH2, the main electronic expansion valve takes the Td _ SH value as the standard, no matter how the SH1 value is adjusted in a large mode, and when Td _ SH1 is more than Td _ SH and less than Td _ SH2, the main electronic expansion valve adjusts the valve opening according to the SH1 value.

Preferably, a tail end liquid pipe temperature sensor and a tail end air pipe temperature sensor respectively acquire a first end temperature Q1 and a second end temperature Q2 in real time, a heat exchange capillary superheat degree SH2= | Q2-Q1|, and a heat exchange capillary refrigeration superheat degree lower limit value T4, a heat exchange capillary refrigeration superheat degree upper limit value T5 and a seedbed environment temperature deviation value T6 are set;

in the refrigeration process, when SH2 is less than or equal to T4, the capillary electronic expansion valve performs valve closing adjustment; when SH2 is larger than or equal to T5, the capillary electronic expansion valve performs valve opening adjustment; when T4 is more than SH2 and less than T5, the capillary electronic expansion valve keeps the current valve opening;

in the heating process, when Tai is less than Tset-T6, the capillary electronic expansion valve performs valve opening large adjustment; when SH2 is larger than Tset + T6, the capillary electronic expansion valve performs valve closing adjustment; when Tset-T6 is more than or equal to SH2 and more than or equal to Tset + T6, the capillary electronic expansion valve keeps the current valve opening.

Preferably, the capillary electronic expansion valve and the solenoid valve on the lowest bed are kept closed during the cooling process, and the capillary electronic expansion valve and the solenoid valve on the uppermost bed are kept closed during the heating process.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a heat pump system according to the present invention;

FIG. 3 is a schematic view of the heat pump system of the present invention in a cooling state;

FIG. 4 is a schematic diagram of the heating state of the heat pump system according to the present invention;

description of reference numerals: 10. a seedbed; 11. a seedbed environment temperature sensor; 20. a heat exchange capillary tube; 21. a distal end liquid tube; 22. a terminal trachea; 23. a capillary tube electronic expansion valve; 24. a tip fluid tube temperature sensor; 25. a terminal tracheal temperature sensor; 26. an electromagnetic valve; 30. a compressor; 31. an exhaust gas temperature sensor; 40. an oil separator; 41. a high pressure switch; 42. a high pressure sensor; 50. a four-way reversing valve; 51. a C port; 52. an E port; 53. an S port; 54. a D port; 60. an outdoor finned heat exchanger; 71. a main-path electronic expansion valve; 72. a high pressure reservoir; 73. a liquid pipe stop valve; 74. a branching pipe; 75. an air pipe stop valve; 76. a shunt tube; 80. a gas-liquid separator; 90. an air intake duct; 91. an intake air temperature sensor; 92. a low pressure sensor; 93. a low pressure switch; 94. and (4) an oil return capillary tube.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the description of the present invention, it should be noted that the terms "bottom", "outside", "front-back", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the state of the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the term "connected" is to be interpreted broadly, e.g. as a fixed connection, a detachable connection, or an integral connection; 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 in specific cases to those skilled in the art.

A seedbed temperature control system and a control method thereof comprise a heat pump unit and a seedbed 10 used for arranging seedlings, wherein the seedbed 10 is provided with a plurality of layers and is arranged at intervals in the vertical direction, the area between the upper layer and the lower layer of the seedbed 10 which are adjacent forms a seedling growing area, heat exchange capillary tubes 20 are laid on the seedbed 10, and the heat exchange capillary tubes 20 are subjected to heat exchange control through the heat pump unit. Wherein the seedbeds 10 are arranged at regular intervals in the vertical direction.

In the above-mentioned scheme, directly set up heat transfer capillary 20 on seedbed 10 to set up multilayer seedbed 10, just so can directly heat and cool down the seedling root system on seedbed 10, all have seedbed 10 in the district of growing seedlings about in addition, that is to say the district of growing seedlings about the homoenergetic heats and cools down, promote ambient temperature's the degree of consistency. Simultaneously the scheme in this application is a heat pump system, can not produce wind-force, prevents to produce the influence to the seedling. The refrigerant is used as a heat exchange medium, and only once heat exchange is performed, so that the heat loss is reduced, and the risks of water leakage and frozen damage to pipelines are avoided; the multiple connection mode is adopted, each seedbed is independently controlled, and the seedbed without temperature control has zero energy consumption; and only adopt local temperature control mode to the bed of growing seedlings, can reduce the energy consumption by a wide margin, realize that crops grow seedlings intelligent, accurate temperature control, realize energy-efficient simultaneously, and do not have the sense of blowing, have important meaning.

Preferably, the heat pump unit comprises a compressor 30, an oil separator 40 and a four-way reversing valve 50 are sequentially connected to a liquid outlet of the compressor 30 through a pipeline, and the four-way reversing valve 50 comprises a C port 51, an E port 52, an S port 53 and a D port 54 communicated with the oil separator 40;

the port C51 is sequentially connected with an outdoor finned heat exchanger 60, a main circuit electronic expansion valve 71, a high-pressure liquid reservoir 72 and a liquid tube stop valve 73 through pipelines, the heat exchange capillary tubes 20 comprise end liquid tubes 21 and end air tubes 22, the liquid tube stop valve 73 is connected with the end liquid tubes 21 on the heat exchange capillary tubes 20 through a branch tube 74, and the capillary tube electronic expansion valve 23 is arranged on the pipeline between the heat exchange capillary tubes 20 and the branch tube 74;

the E port 52 is connected with an air pipe stop valve 75 through a pipeline, and the air pipe stop valve 75 is connected with the end air pipes 22 on the plurality of heat exchange capillary tubes 20 through shunt tubes 76;

the S port 53 is connected to a gas-liquid separator 80 through a pipe, and an outlet of the gas-liquid separator 80 is provided with a suction pipe 90 communicating with the compressor 30. In the heating mode, the compressor 30 is started, and the four-way reversing valve 50 is controlled to be communicated with the D port 54 and the E port 52 and communicated with the C port 51 and the S port 53; in the cooling mode, the compressor 30 is started and the four-way selector valve 50 is controlled to communicate between the D port 54 and the C port 51 and to communicate between the E port 52 and the S port 53.

Preferably, an exhaust temperature sensor 31 is provided on a pipeline between the compressor 30 and the oil separator 40, a high pressure switch 41 and a high pressure sensor 42 are provided on a pipeline between the oil separator 40 and the four-way selector valve 50, a terminal liquid pipe temperature sensor 24 is provided on the terminal liquid pipe 21, a terminal gas pipe temperature sensor 25 and an electromagnetic valve 26 are provided on the terminal gas pipe 22, and a bed environment temperature sensor 11 is provided on the seedbed 10. Each sensor is used to sense the system and provide a parameter from which the system develops its control.

Preferably, the intake pipe 90 is provided with an intake air temperature sensor 91, a low pressure sensor 92, and a low pressure switch 93, an oil return capillary tube 94 is connected between the oil separator 40 and the intake pipe 90, and a connection end of the oil return capillary tube 94 is located between the intake air temperature sensor 91 and the low pressure sensor 92. The oil return capillary 94 is used to return excess media in the oil separator 40 back to the system. The high-pressure switch 41 and the high-pressure sensor 42 are arranged in this order in the flow direction, and the intake air temperature sensor 91, the low-pressure sensor 92, and the low-pressure switch 93 are arranged in this order in the flow direction.

s1, intelligently judging the operation mode of an air conditioning system according to the detected ambient temperature of the seedbed:

monitoring and obtaining the seedbed environment temperature Tai in real time through a seedbed environment temperature sensor 11, and presetting a user heating temperature value Tset1, a user refrigerating temperature value Tset2 and an environment temperature deviation value T7;

s2, judging whether to refrigerate or heat according to the value of the seedbed environment temperature Tai:

when the ambient temperature Tai of the seedbed is less than Tset1, the system starts the heating mode, starts the compressor 30, controls the four-way reversing valve 50 to act, enables the D port 54 to be communicated with the E port 52, enables the C port 51 to be communicated with the S port 53, and enables the medium in the compressor 30 to flow along the following routes:

the method comprises the following steps of 1, a compressor 30, an oil separator 40, a D port 54, an E port 52, an air pipe stop valve 75, a shunt pipe 76, an electromagnetic valve 26, a tail end air pipe 22, a heat exchange capillary tube 20, a tail end liquid pipe 21, a capillary electronic expansion valve 23, a branch pipe 74, a liquid pipe stop valve 73, a high-pressure liquid storage device 72, a main circuit electronic expansion valve 71, an outdoor fin heat exchanger 60, a C port 51, an S port 53, a gas-liquid separator 80, an air suction pipe 90 and the compressor 30;

when the ambient temperature Tai of the seedbed is more than Tset2, the system starts a refrigeration mode, starts the compressor 30, controls the four-way reversing valve 50 to act, enables the D port 54 to be communicated with the C port 51, enables the E port 52 to be communicated with the S port 53, and enables the medium in the compressor 30 to flow along the following routes:

the air compressor 30, the oil separator 40, the D port 54, the C port 51, the outdoor finned heat exchanger 60, the main circuit electronic expansion valve 71, the high-pressure liquid reservoir 72, the liquid tube stop valve 73, the branch tube 74, the capillary electronic expansion valve 23, the tail end liquid tube 21, the heat exchange capillary tube 20, the tail end air tube 22, the electromagnetic valve 26, the branch tube 76, the air tube stop valve 75, the E port 52, the S port 53, the air-liquid separator 80, the air suction tube 90 and the air compressor 30 are sequentially connected;

s3, compressor 30 shutdown condition:

in the heating process, when the ambient temperature Tai of the seedbed is more than Tset1+ T7, the compressor 30 is stopped;

in the refrigeration process, when the ambient temperature Tai of the seedbed is less than Tset2-T7, the compressor 30 is stopped.

As shown in fig. 4, the high-temperature and high-pressure gaseous refrigerant compressed by the dc compressor 30 passes through the oil separator 40, the four-way reversing valve 50, the air pipe stop valve 75, and the branch pipes 76, and each path of refrigerant passes through the electromagnetic valve 26, enters the heat exchange capillary tubes 20 of each layer, and performs radiation heat exchange with the ambient air of each layer of seedbed to heat the environment of each layer of seedbed. After radiation heat exchange, the refrigerant in each layer of heat exchange capillary tube 20 passes through the capillary tube electronic expansion valve 18, and is merged with one path of refrigerant in the two layers of bottom capillary tubes at the branch tube 74 through the capillary tube electronic expansion valve 23, the merged refrigerant enters the outdoor fin heat exchanger 4 through the liquid tube stop valve 73, the high-pressure liquid reservoir 72 and the main path electronic expansion valve 71 for throttling and then carries out heat convection with air, the refrigerant after evaporation and heat absorption enters the gas-liquid separator 80 through the four-way reversing valve 50, the liquid refrigerant is deposited at the bottom of the gas-liquid separator 80, the gas refrigerant returns to the compressor 30 for compression, the heating mode is completed, and the temperature rise control is carried out on the seedbed.

As shown in fig. 3, the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 30 passes through the oil separator 40 and the four-way reversing valve 50, enters the outdoor fin heat exchanger 60 to perform heat convection with outdoor air, is condensed to release heat, is changed into a medium-temperature and medium-pressure liquid refrigerant, and then passes through the main circuit electronic expansion valve 71, the high-pressure liquid reservoir 72, the liquid tube stop valve 73 and the branch tube 74. Then, one path of refrigerant is branched after passing through the branch pipe 74, and each path of refrigerant enters each layer of capillary after being throttled by the capillary electronic expansion valve 23, and performs radiation heat exchange with each layer of seedbed environment air to cool each layer of seedbed environment. After the radiation heat exchange, one path of refrigerant of the heat exchange capillary tube 20 passes through the electromagnetic valve 26 and is merged with other paths of refrigerant at the flow dividing pipe 76. The merged refrigerant enters the gas-liquid separator 80 through the gas pipe stop valve 75 and the four-way reversing valve 50, the liquid refrigerant is deposited at the bottom of the gas-liquid separator, the gas refrigerant returns to the compressor 30 to be compressed, the refrigeration mode is completed, and the cooling control is performed on the seedbed. In the scheme, the four-way reversing valve 50 is switched to directly realize the switching between the refrigeration and the heating, so that the refrigeration and the heating can be realized without two systems, and the system equipment is reduced.

When in use

When the frequency is increased, the frequency of the compressor 30 is controlled; when in use

While, the current compressor 30 frequency is maintained; when in use

The compressor 30 frequency is down-controlled, wherein

For the calculated average temperature of the startup seedbed in the period,

the average temperature of the starting seedbed calculated in the last period is t, and the frequency adjustment period of the compressor 30 is t;

in the process of refrigeration, when

In good time and securityHold current compressor 30 frequency; when in use

The frequency of the compressor 30 is down-controlled. The frequency control of the frequency of the compressor 30 keeps the temperature of the system in a stable range all the time, and prevents the compressor 30 from being started and stopped frequently. The average temperature in the above scheme is calculated by collecting the temperature at each time point, for example, collecting the temperature once per second, and dividing the sum of the collected temperatures by the number of times of collection to obtain the average temperature of the seedbed

The time corresponding to the acquisition times can be single cycle time, and the same

The calculation method is that the sum of the temperatures collected in the period is divided by the collection times.

Preferably, the air suction temperature sensor 91 acquires air suction temperature Ts in real time, the low pressure sensor 92 acquires low pressure in real time, a pressure-saturation temperature comparison table is inquired to acquire saturation temperature Ps _ T corresponding to the low pressure, air suction superheat SH1= Ts-Ps _ T of a temperature control system is defined, and preset air suction superheat deviation range values are T2 and T3 and an air suction superheat intermediate value SH1_ tar;

in the refrigeration process, the main-path electronic expansion valve 71 keeps the maximum opening degree;

in the heating process, when SH1 is less than or equal to SH1_ tar-T2, the main electronic expansion valve 71 performs valve closing adjustment; when SH1 is more than or equal to SH1_ tar + T3, the main-path electronic expansion valve 71 performs valve opening adjustment; when SH1_ tar-T2 is less than SH1 and less than SH1_ tar + T3, the main electronic expansion valve 71 keeps the current valve opening. When the refrigeration mode is operated, the flow rate of the circulating refrigerant of the temperature control system is ensured, and the main electronic expansion valve 71 keeps the maximum opening degree. When the heating mode is operated, the main electronic expansion valve 71 is controlled and adjusted according to the target suction superheat SH1_ tar of the temperature control system. Meanwhile, the exhaust superheat degree of the temperature control system is controlled within a certain range through the correction control adjustment of the main-path electronic expansion valve 71, so that the running stability and reliability of the compressor are ensured.

Preferably, the exhaust temperature sensor 31 acquires an exhaust temperature Td in real time, the high pressure sensor 42 acquires a high pressure in real time, a pressure-saturation temperature comparison table is queried to acquire a saturation temperature Pd _ t corresponding to the high pressure, an exhaust superheat degree Td _ SH = Td-Pd _ t of the temperature control system is defined, and an exhaust superheat degree lower limit value Td _ SH1 and an exhaust superheat degree upper limit value Td _ SH2 are set;

when Td _ SH is less than or equal to Td _ SH1, the main electronic expansion valve 71 takes Td _ SH as the reference, and no matter how SH1 value is adjusted for small valve opening, when Td _ SH is greater than or equal to Td _ SH2, the main electronic expansion valve 71 takes Td _ SH as the reference, and no matter how SH1 value is adjusted for large valve opening, when Td _ SH1 is less than Td _ SH < Td _ SH2, the main electronic expansion valve 71 adjusts valve opening according to SH1 value.

Preferably, the tail end liquid pipe temperature sensor 24 and the tail end air pipe temperature sensor 25 respectively collect the first end temperature Q1 and the second end temperature Q2 in real time, define the superheat degree SH2= | Q2-Q1|, and set a lower limit value T4 of the refrigeration superheat degree of the heat exchange capillary 20, an upper limit value T5 of the refrigeration superheat degree of the heat exchange capillary 20 and a deviation value T6 of the ambient temperature of the seedbed;

in the refrigeration process, when SH2 is less than or equal to T4, the capillary electronic expansion valve 23 performs valve closing adjustment; when SH2 is more than or equal to T5, the capillary electronic expansion valve 23 performs valve opening adjustment; when T4 is more than SH2 and less than T5, the capillary electronic expansion valve 23 keeps the current valve opening;

in the heating process, when Tai is less than Tset-T6, the capillary electronic expansion valve 23 performs valve opening large adjustment; when SH2 is more than Tset + T6, the capillary electronic expansion valve 23 performs valve closing adjustment; when Tset-T6 is more than or equal to SH2 and more than or equal to Tset + T6, the capillary electronic expansion valve 23 keeps the current valve opening.

Meanwhile, in the refrigeration process, in order to ensure the uniformity of the refrigerant of the starting seedbed, the average environmental temperature of the starting seedbed is determined

And correcting and controlling the difference value with the environmental temperature Tai of the starting seedbed. When the temperature is higher than the set temperature

And when the value is larger than the preset value A1, the corresponding seedbed electronic expansion valve performs valve opening correction control. When in use

If the value is less than the preset value A2, the corresponding seedbed electronic expansion valve carries out valve closing correction control. When in use

The corresponding seedbed electronic expansion valve is not corrected and adjusted.

When the heating mode is operated, in order to ensure the uniformity of the refrigerant of the starting seedbed, the average environmental temperature of the starting seedbed is determined

And correcting and controlling the difference value with the environmental temperature Tai of the starting seedbed. When in use

And (3) carrying out valve closing correction control on the corresponding seedbed electronic expansion valve according to a preset value A3. When in use

And the corresponding seedbed electronic expansion valve is used for carrying out valve opening major correction control. When a preset value is reached

Therefore, the system can realize independent temperature control on each seedbed, can be used for carrying out local temperature control on the seedbed with seedling culture requirements in a targeted manner, and has no seedbed energy consumption of the seedling culture requirements. The system can provide a uniform temperature field without air blowing in the crop seedling raising process, realize intelligent and accurate temperature control, ensure seedling raising results, greatly reduce the energy consumption in the seedling raising process, improve the temperature control effect and reduce the initial investment of equipment.

Preferably, the capillary electronic expansion valve 23 and the solenoid valve 26 on the lowermost bed 10 are kept closed during the cooling process, and the capillary electronic expansion valve 23 and the solenoid valve 26 on the uppermost bed 10 are kept closed during the heating process. Because cold air lower floor, hot-air come-up, so when each seedbed environment needs refrigeration cooling: opening capillaries at the bottom of the two layers of seedbeds, cooling the environment of the first layer of seedbed, and simultaneously assisting in cooling the environment of the second layer of seedbed; opening a capillary tube at the bottom of the three-layer seedbed, cooling the environment of the two-layer seedbed, and simultaneously assisting in cooling the environment of the three-layer seedbed; and opening the capillary tubes at the top of the three layers to cool the three layers of seedbed environments. When the seedbed environment needs heating and temperature rising, opening a layer of seedbed bottom capillary tubes, and rising the temperature of the layer of seedbed environment; opening the two-layer bottom capillary tube, heating the two-layer seedbed environment, and simultaneously assisting the one-layer seedbed environment to heat; and opening the capillary tubes at the bottom of the three layers to heat the three-layer seedbed environment and simultaneously assist the two-layer seedbed environment in heating.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and such changes and modifications will fall within the scope of the present invention.

Claims

1. The utility model provides a seedbed temperature control system which characterized in that: including heat pump unit and be used for arranging seedbed (10) of seedling, seedbed (10) are provided with the multilayer and follow vertical interval arrangement, and two-layer about adjacent regional constitution seedling growing area between seedbed (10), seedbed (10) upper berth is equipped with heat transfer capillary (20), heat transfer capillary (20) are carried out heat transfer control by heat pump unit.

2. The temperature control system for a seedbed of claim 1, wherein: the heat pump unit comprises a compressor (30), a liquid outlet of the compressor (30) is sequentially connected with an oil separator (40) and a four-way reversing valve (50) through a pipeline, and the four-way reversing valve (50) comprises a C port (51), an E port (52), an S port (53) and a D port (54) communicated with the oil separator (40);

the heat exchange capillary tube (20) comprises a plurality of heat exchange capillary tubes (20), a C port (51) and a liquid tube stop valve (73), wherein the C port (51) is sequentially connected with an outdoor fin heat exchanger (60), a main circuit electronic expansion valve (71), a high-pressure liquid reservoir (72) and the liquid tube stop valve (73) through pipelines, the heat exchange capillary tube (20) comprises a tail end liquid tube (21) and a tail end air tube (22), the liquid tube stop valve (73) is connected with the tail end liquid tubes (21) on the heat exchange capillary tubes (20) through a branch tube (74), and a capillary tube electronic expansion valve (23) is arranged on the pipeline between the heat exchange capillary tube (20) and the branch tube (74);

the E port (52) is connected with an air pipe stop valve (75) through a pipeline, and the air pipe stop valve (75) is connected with tail end air pipes (22) on the heat exchange capillary pipes (20) through shunt pipes (76);

the S port (53) is connected with a gas-liquid separator (80) through a pipeline, and an air suction pipe (90) communicated with the compressor (30) is arranged at an outlet of the gas-liquid separator (80).

3. The temperature control system for a seedbed as set forth in claim 2, wherein: be provided with exhaust temperature sensor (31) on the pipeline between compressor (30) and oil separator (40), be equipped with high-pressure switch (41) and high-pressure sensor (42) on the pipeline between oil separator (40) and four-way reversing valve (50), terminal liquid pipe (21) department is provided with terminal liquid pipe temperature sensor (24), terminal trachea (22) department is provided with terminal trachea temperature sensor (25) and solenoid valve (26), be provided with seedbed ambient temperature sensor (11) on seedbed (10).

4. The temperature control system for a seedbed of claim 3, wherein: the oil separator is characterized in that the air suction pipe (90) is provided with an air suction temperature sensor (91), a low-pressure sensor (92) and a low-pressure switch (93), an oil return capillary tube (94) is connected between the oil separator (40) and the air suction pipe (90), and the connecting end of the oil return capillary tube (94) is located between the air suction temperature sensor (91) and the low-pressure sensor (92).

5. A control method of the temperature control system for a seedbed as set forth in any of claims 1 to 4, characterized in that: the method comprises the following steps:

s1, monitoring and obtaining a seedbed environment temperature Tai in real time through a seedbed environment temperature sensor (11), and presetting a user heating temperature value Tset1, a user refrigerating temperature value Tset2 and an environment temperature deviation value T7;

s2, when the seedbed environment temperature Tai is less than Tset1, the system starts a heating mode, starts the compressor (30), controls the four-way reversing valve (50) to act, enables the D port (54) to be communicated with the E port (52), enables the C port (51) to be communicated with the S port (53), and enables a medium in the compressor (30) to flow along the following routes:

compressor (30) -oil separator (40) -D port (54) -E port (52) -gas pipe cut-off valve (75) -shunt tube (76) -solenoid valve (26) -end gas pipe (22) -heat exchange capillary tube (20) -end liquid pipe (21) -capillary tube electronic expansion valve (23) -branch tube (74) -liquid pipe cut-off valve (73) -high pressure reservoir (72) -main circuit electronic expansion valve (71) -outdoor fin heat exchanger (60) -C port (51) -S port (53) -gas-liquid separator (80) -gas suction pipe (90) -compressor (30);

when the ambient temperature Tai of the seedbed is more than Tset2, the system starts a refrigeration mode, starts a compressor (30), controls the action of a four-way reversing valve (50), enables a D port (54) to be communicated with a C port (51), enables an E port (52) to be communicated with an S port (53), and enables a medium in the compressor (30) to flow along the following routes:

compressor (30) -oil separator (40) -D port (54) -C port (51) -outdoor finned heat exchanger (60) -main circuit electronic expansion valve (71) -high pressure reservoir (72) -liquid pipe stop valve (73) -branch pipe (74) -capillary tube electronic expansion valve (23) -end liquid pipe (21) -heat exchange capillary tube (20) -end air pipe (22) -solenoid valve (26) -branch pipe (76) -air pipe stop valve (75) -E port (52) -S port (53) -gas-liquid separator (80) -suction pipe (90) -compressor (30);

s3, in the heating process, when the ambient temperature Tai of the seedbed is more than Tset1+ T7, stopping the compressor (30);

in the refrigeration process, when the ambient temperature Tai of the seedbed is less than Tset2-T7, the compressor (30) is stopped.

6. The method of controlling a temperature control system for a seedbed as set forth in claim 5, wherein: presetting a temperature intermediate value Tset of a seedbed, a preset value T1 of temperature range deviation and a preset value delta T of unit time change rate;

When in use

When the frequency of the compressor (30) is increased, the frequency is controlled; when in use

While maintaining the current compressor (30) frequency; when in use

When the frequency of the compressor (30) is controlled in a frequency reduction mode;

in the process of refrigeration, when

While maintaining the current compressor (30) frequency; when in use

wherein

For the calculated average temperature of the startup seedbed in the period,

the average temperature of the starting seedbed calculated in the last period is t, and the frequency adjustment period of the compressor (30) is t.

7. The method of controlling a temperature control system for a seedbed as set forth in claim 5, wherein: the suction temperature sensor (91) acquires suction temperature Ts in real time, the low-pressure sensor (92) acquires low-pressure in real time, a pressure-saturation temperature comparison table is inquired to acquire saturation temperature Ps _ T corresponding to the low-pressure, suction superheat SH1= Ts-Ps _ T of the temperature control system is defined, and deviation range values of the suction superheat are preset to be T2 and T3 and a suction superheat intermediate value SH1_ tar;

in the refrigeration process, the main electronic expansion valve (71) keeps the maximum opening;

in the heating process, when SH1 is less than or equal to SH1_ tar-T2, the main electronic expansion valve (71) performs valve closing adjustment; when SH1 is larger than or equal to SH1_ tar + T3, the main-path electronic expansion valve (71) performs valve opening adjustment; when SH1_ tar-T2 is less than SH1 and less than SH1_ tar + T3, the main electronic expansion valve (71) keeps the current valve opening.

8. The method of controlling a temperature control system for a seedbed as set forth in claim 7, wherein: the exhaust temperature sensor (31) acquires an exhaust temperature Td in real time, the high pressure sensor (42) acquires a high pressure in real time, a pressure-saturation temperature comparison table is inquired to acquire a saturation temperature Pd _ t corresponding to the high pressure, an exhaust superheat Td _ SH = Td-Pd _ t of a temperature control system is defined, and an exhaust superheat lower limit Td _ SH1 and an exhaust superheat upper limit Td _ SH2 are set;

when Td _ SH is less than or equal to Td _ SH1, the valve is adjusted in a small-opening mode, when Td _ SH is more than or equal to Td _ SH2, the main electronic expansion valve (71) is adjusted in a large-opening mode, and when Td _ SH1 is less than Td _ SH and less than Td _ SH2, the main electronic expansion valve (71) is adjusted in a valve opening mode according to the value of SH 1.

9. The method of controlling a temperature control system for a seedbed as set forth in claim 5, wherein:

a tail end liquid pipe temperature sensor (24) and a tail end air pipe temperature sensor (25) respectively acquire a first end temperature Q1 and a second end temperature Q2 in real time, define the superheat degree SH2= | Q2-Q1| of a heat exchange capillary (20), and set a refrigeration superheat degree lower limit value T4 of the heat exchange capillary (20), a refrigeration superheat degree upper limit value T5 of the heat exchange capillary (20) and a seedbed environment temperature deviation value T6;

in the refrigeration process, when SH2 is less than or equal to T4, the capillary electronic expansion valve (23) performs valve closing adjustment; when SH2 is larger than or equal to T5, the capillary electronic expansion valve (23) performs valve opening large adjustment; when T4 is more than SH2 and less than T5, the capillary electronic expansion valve (23) keeps the current valve opening;

in the heating process, when Tai is less than Tset-T6, the capillary electronic expansion valve (23) performs valve opening adjustment; when SH2 is more than Tset + T6, the capillary electronic expansion valve (23) performs valve closing adjustment; when Tset-T6 is more than or equal to SH2 and more than or equal to Tset + T6, the capillary electronic expansion valve (23) keeps the current valve opening.

10. The method of controlling a temperature control system for a seedbed according to claim 6, 7, 8 or 9, characterized in that: in the cooling process, the capillary electronic expansion valve (23) and the electromagnetic valve (26) on the seedbed (10) at the lowest layer are kept in a closed state, and in the heating process, the capillary electronic expansion valve (23) and the electromagnetic valve (26) on the seedbed (10) at the uppermost layer are kept in a closed state.