A control method and control system of a fresh air handling unit

Abstract

The application relates to a control method and a control system of a fresh air unit, and relates to the technical field of a fresh air system. The control method comprises the following steps: collecting first temperature data of fresh air at an air inlet of a cross-flow heat exchanger; judging whether the first temperature data is less than a first temperature threshold value; if the first temperature data is less than the first temperature threshold value, heating is supplied by a surface air cooler to preheat fresh air flowing through the cross-flow heat exchanger; and if the first temperature data is not less than the first temperature threshold value, fresh air is sent to the surface air cooler, and the fresh air is heated by the surface air cooler. The application has the effect that the surface air cooler can be prevented from being frozen and cracked by low-temperature fresh air.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fresh air systems, in particular to a control method and control system of a fresh air handling unit. BACKGROUND

[0002] The fresh air handling unit is an air conditioning equipment for providing fresh air. The working principle is to extract fresh air from the outdoor, and after dust removal, dehumidification or humidification, temperature rise or fall, etc., the air is sent to the indoor by the fan, and replaces the original air in the indoor space when entering the indoor space.

[0003] The related technology discloses a fresh air handling unit, which comprises a box body, an air inlet and an air outlet are formed on opposite sides of the box body, a primary filter is fixedly arranged at the air inlet of the box body, the primary filter covers the air inlet, a surface cooler and a heat exchanger are arranged on one side of the box body close to the air inlet, a centrifugal fan is arranged on one side of the box body close to the air outlet, and the air outlet of the centrifugal fan is communicated with the air outlet of the box body, wherein the surface cooler and the heat exchanger are often connected with liquid medium to exchange heat with air.

[0004] According to the related technology, the high-temperature medium in the surface cooler and the heat exchanger can conduct heat to the air in the box body, so as to improve the temperature of the air in the box body, and the air is sent into the indoor through the centrifugal fan. However, in some northern regions of China, the temperature can reach-22℃ in cold weather. At this time, the cold air enters the box body, which is easy to freeze the surface cooler and cause the fresh air handling unit to be difficult to work normally, and improvement is needed. SUMMARY

[0005] The purpose of the present application is to provide a control method and control system of a fresh air handling unit, which can preheat the fresh air entering the fresh air handling unit to avoid the surface cooler from being frozen.

[0006] In the first aspect, the present application provides a control method of a fresh air handling unit, which adopts the following technical scheme:

[0007] A control method of a fresh air handling unit, comprising:

[0008] Collecting first temperature data of fresh air at an air inlet of a cross-flow heat exchanger;

[0009] Judging whether the first temperature data is less than a first temperature threshold value;

[0010] If the first temperature data is less than the first temperature threshold value, heating is supplied through a surface cooler to preheat the fresh air flowing through the cross-flow heat exchanger;

[0011] If the first temperature data is not less than the first temperature threshold value, the fresh air is sent to the surface cooler, and the fresh air is heated through the surface cooler.

[0012] By adopting the technical scheme, the first temperature data is collected, and it is judged whether the first temperature data is less than the first temperature threshold value, and then when the first temperature data is less than the first temperature threshold value, the cross-flow heat exchanger is used to preheat the fresh air, so as to improve the temperature of the fresh air, thereby avoiding that the surface cooler is frozen and cracked by the low-temperature fresh air.

[0013] Optionally, after the surface cooler is used to preheat the fresh air flowing through the cross-flow heat exchanger, the method further comprises:

[0014] collecting second temperature data of the fresh air at an air outlet of the cross-flow heat exchanger;

[0015] judging whether the second temperature data is not less than the first temperature threshold value;

[0016] if the second temperature data is not less than the first temperature threshold value, the preheated fresh air is sent to the surface cooler, and the fresh air is heated by the surface cooler;

[0017] if the second temperature data is less than the first temperature threshold value, the water valve opening degree of the surface cooler is increased, an alarm information is sent, and the fan and the fresh air sealing air valve are closed.

[0018] By adopting the technical scheme, the second temperature data is collected, and it is judged whether the second temperature data is not less than the first temperature threshold value, and then when the second temperature data is less than the first temperature threshold value, the water valve opening degree of the surface cooler is increased to improve the temperature of the fresh air, and an alarm information is sent, and the fan and the fresh air sealing air valve are closed, thereby further avoiding that the surface cooler is frozen and cracked by the low-temperature fresh air.

[0019] Optionally, after the surface cooler is used to heat the fresh air, the method further comprises:

[0020] the heated fresh air is heated again by the heat exchanger;

[0021] third temperature data of the fresh air after being heated again is collected;

[0022] it is judged whether the third temperature data is not less than a second temperature threshold value;

[0023] if the third temperature data is not less than the second temperature threshold value, the blowing power of the fan is increased, and the fresh air after being heated again is blown into the room by the fan;

[0024] if the third temperature data is less than the second temperature threshold value, the heating temperature of the heat exchanger is increased, and the blowing power of the fan is reduced, so that the fresh air after being heated again is blown into the room by the fan.

[0025] By adopting the technical scheme, the third temperature data is collected, and it is judged whether the third temperature data is not less than the second temperature threshold value, and then when the third temperature data is not less than the second temperature threshold value, the blowing power of the fan is increased, then the new air heated again is blown to the indoor by the fan, when the third temperature data is less than the second temperature threshold value, the heating temperature of the heat exchanger is increased, and the blowing power of the fan is reduced, then the new air heated again is blown to the indoor by the fan, so that the temperature of the new air flowing to the indoor can be ensured.

[0026] Optionally, the heat exchanger is provided with a heating coil, and the new air is heated again by the heating coil, and specifically comprises:

[0027] The tube temperature of the heating coil is monitored in real time;

[0028] According to the tube temperature and the preset anti-freezing protection temperature threshold value, the temperature control target is switched;

[0029] According to the current temperature control target, the medium flow of the heating coil is adjusted, so that the measured temperature corresponding to the current temperature control target reaches the target temperature.

[0030] By adopting the technical scheme, according to the tube temperature and the preset anti-freezing protection temperature threshold value, the temperature control target is switched, and then according to the current temperature control target, the medium flow of the heating coil is adjusted, so that the measured temperature corresponding to the current temperature control target reaches the target temperature, so that the correspondence between the measured temperature and the target temperature can be ensured.

[0031] Optionally, according to the tube temperature and the preset anti-freezing protection temperature threshold value, the temperature control target is switched, and specifically comprises:

[0032] The tube temperature is compared with the preset anti-freezing protection temperature threshold value to determine the interval in which the tube temperature is located;

[0033] According to the determined interval, the temperature control target is switched.

[0034] By adopting the technical scheme, by comparing the tube temperature with the preset anti-freezing protection temperature threshold value, the interval in which the tube temperature is located can be determined, and then according to the determined interval, the temperature control target is switched, so that the temperature control target can be conveniently switched.

[0035] Optionally, according to the determined interval, the temperature control target is switched, and specifically comprises:

[0036] If the tube temperature is greater than or equal to the sum of the preset anti-freezing protection temperature threshold value and a preset value and lasts for a preset time, the first temperature control target is switched to, wherein the measured temperature corresponding to the first temperature control target is a room temperature, and the target temperature is a user set temperature.

[0037] If the pipe body temperature is less than or equal to the preset freeze protection temperature threshold value and lasts for a preset time, a second temperature control target is switched to, wherein the second temperature control target corresponds to the pipe body temperature as the measured temperature and the preset freeze protection temperature threshold value as the target temperature;

[0038] If the pipe body temperature is greater than the preset freeze protection temperature threshold value and less than the sum of the preset freeze protection temperature threshold value and the preset value and lasts for a preset time, the last determined temperature control target is kept unchanged.

[0039] By adopting the above technical solution, the relationship between the pipe body temperature, the preset freeze protection temperature threshold value and the preset value is judged, and corresponding measures are taken to ensure the temperature flowing into the room.

[0040] Optionally, the heating coil is connected with a medium inflow pipeline, a heat supply control valve is arranged on the medium inflow pipeline, and the medium flow of the heating coil is adjusted according to the current temperature control target, specifically including:

[0041] If the measured temperature is greater than the target temperature, the opening degree of the heat supply control valve is reduced;

[0042] If the measured temperature is equal to the target temperature, the current opening degree of the heat supply control valve is kept unchanged;

[0043] If the measured temperature is less than the target temperature, the opening degree of the heat supply control valve is increased.

[0044] By adopting the above technical solution, the opening degree of the heat supply control valve is adjusted according to the comparison between the measured temperature and the target temperature, so that the temperature flowing into the room can be further ensured.

[0045] In a second aspect, the application provides a control system of a fresh air handling unit, which adopts the following technical solution:

[0046] A control system of a fresh air handling unit, comprising:

[0047] A collection module is configured to collect first temperature data of fresh air at an inlet of a cross-flow heat exchanger;

[0048] A judgment module is configured to judge whether the first temperature data is less than a first temperature threshold value;

[0049] A first execution module is configured to preheat fresh air flowing through the cross-flow heat exchanger by heat supply of a surface air cooler when the first temperature data is less than the first temperature threshold value;

[0050] The second execution module is configured to, when the first temperature data is not less than the first temperature threshold, send fresh air to the surface cooler and heat the fresh air by the surface cooler.

[0051] By using the above technical solution, the first temperature data is collected by the collection module, and the judgment module is used to judge whether the first temperature data is less than the first temperature threshold. Then, by means of the first execution module, when the first temperature data is less than the first temperature threshold, the fresh air is preheated by the cross-flow heat exchanger to improve the temperature of the fresh air, so that the surface cooler can be prevented from being frozen and cracked by the fresh air with low temperature.

[0052] In a third aspect, the application provides a terminal, which adopts the following technical solution:

[0053] A terminal comprises a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor loads the computer program, the method of the first aspect is executed.

[0054] By using the above technical solution, the computer program of the first aspect is generated and stored in the memory to be loaded and executed by the processor, so that the user can establish contact with the control system of the fresh air handling unit through the terminal and query the processed contents of the system.

[0055] In a fourth aspect, the application provides a computer readable storage medium, which adopts the following technical solution:

[0056] A computer readable storage medium stores a computer program. When the computer program is loaded by a processor, the method of the first aspect is executed.

[0057] By using the above technical solution, the computer program of the first aspect is generated and stored in the computer readable storage medium. After the computer readable storage medium is loaded into any computer, the computer can execute the method of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 is a structure schematic diagram of the fresh air handling unit in the embodiment of the application;

[0059] Figure 2 is a method flowchart of steps S1-S4 in the embodiment of the application;

[0060] Figure 3 is a method flowchart of steps S5-S8 in the embodiment of the application;

[0061] Figure 4 is a method flowchart of steps S9-S13 in the embodiment of the application;

[0062] Figure 5 is a method flowchart of steps S14-step S16 in the embodiment of the present application;

[0063] Figure 6 is a method flowchart of steps S151-step S152 in the embodiment of the present application;

[0064] Figure 7 is a method flowchart of steps S1521-step S1523 in the embodiment of the present application;

[0065] Figure 8 is a method flowchart of steps S17-step S19 in the embodiment of the present application;

[0066] Figure 9 is a module framework diagram of the control system of the fresh air handling unit in the embodiment of the present application;

[0067] In the figure, 1, shell; 11, fresh air inlet; 12, fresh air outlet; 13, blocking plate; 14, air inlet compartment; 141, air baffle; 142, surface cooler; 143, cross-flow heat exchanger; 144, first expansion valve; 15, air supply compartment; 151, first heat exchanger; 152, heat recovery condenser; 153, fan; 154, second expansion valve; 155, third expansion valve; 2, compressor; 3, second heat exchanger; 4, acquisition module; 5, judgment module; 6, first execution module; 7, second execution module. DETAILED DESCRIPTION

[0068] The following will be combined with the accompanying Figure 1 -Appendix Figure 9 , the present application is further described in detail.

[0069] The control method of the fresh air handling unit disclosed in the present application mainly describes the use process of the fresh air handling unit in winter.

[0070] Referring to Figure 1 , the embodiment of the present application discloses a fresh air handling unit, which comprises a shell 1, the length direction of the shell 1 is horizontally arranged, the length direction of the shell 1 is provided with a fresh air inlet 11 and a fresh air outlet 12 on both sides, and the fresh air inlet 11 is outdoor and the fresh air outlet 12 is indoor.

[0071] Among them, the middle part of the shell 1 is fixed with a blocking plate 13, the blocking plate 13 is vertically arranged, the circumferential side of the blocking plate 13 abuts against the upper and lower side walls and the two side walls in the width direction of the shell 1, the air inlet compartment 14 is formed on the side of the blocking plate 13 close to the fresh air inlet 11 in the shell 1, the air supply compartment 15 is formed on the side of the blocking plate 13 close to the fresh air outlet 12 in the shell 1, and the middle part of the blocking plate 13 is provided with a ventilation opening 131.

[0072] The air baffle 141, the surface cooler 142 and the cross-flow heat exchanger 143 are arranged in the air inlet compartment 14, the surface cooler 142 is communicated with a heat medium flow pipeline, and the first expansion valve 144 is installed on the heat medium flow pipeline and used for controlling the conduction of the heat medium flow pipeline. In specific application, the outdoor fresh air enters the air inlet compartment 14 from the fresh air inlet 11, and then is preheated by the cross-flow heat exchanger 143, and then is heated by the surface cooler 142, and then the heated fresh air is delivered to the air supply compartment 15 through the cross-flow heat exchanger 143 and the air outlet 131.

[0073] The first heat exchanger 151, the heat recovery condenser 152 and the fan 153 are arranged in the air supply compartment 15, the first heat exchanger 151 is communicated with the heat recovery condenser 152, the second expansion valve 154 and the third expansion valve 155 are arranged on the communication pipeline of the first heat exchanger 151 and the heat recovery condenser 152, and the second expansion valve 154 and the third expansion valve 155 are used for controlling the conduction of the communication pipeline of the first heat exchanger 151 and the heat recovery condenser 152. In specific application, the heated fresh air is heated again by the first heat exchanger 151, and finally is delivered to the indoor environment by the fan 153.

[0074] The compressor 2 and the second heat exchanger 3 are arranged outside the shell 1, one side of the first heat exchanger 151 is communicated with the compressor 2, the other side of the first heat exchanger 151 is respectively communicated with the heat recovery condenser 152 and one side of the second heat exchanger 3, and the other side of the second heat exchanger 3 is communicated with the compressor 2.

[0075] Further, in cold weather, the second expansion valve 154 is opened, the third expansion valve 155 is closed, the compressor 2, the first heat exchanger 151, the second expansion valve 154 and the second heat exchanger 3 are matched, and the fresh air is heat-exchanged by the first heat exchanger 151 to improve the temperature of the fresh air. In hot weather, the second expansion valve 154 is closed, the third expansion valve 155 is opened, the compressor 2, the second heat exchanger 3, the heat recovery condenser 152, the third expansion valve 155 and the first heat exchanger 151 are matched, and the fresh air is heat-exchanged by the first heat exchanger 151 to reduce the temperature of the fresh air.

[0076] The embodiment of the application discloses a control method of a fresh air handling unit, referring to Figure 2 , and specifically includes the following steps:

[0077] S1: collecting first temperature data of fresh air at the cross-flow heat exchanger air inlet.

[0078] In one embodiment of the present application, a high-precision temperature sensor is installed at the air inlet of the cross-flow heat exchanger, and the first temperature data at the air inlet of the cross-flow heat exchanger is collected in real time by the high-precision temperature sensor.

[0079] S2: Determine whether the first temperature data is less than the first temperature threshold.

[0080] In the present embodiment, the first temperature threshold is set to 2°C, and of course, the set value of the first temperature threshold can be adjusted according to the actual use; and then determine whether the first temperature data collected in step S1 is less than 2°C.

[0081] S3: If the first temperature data is less than the first temperature threshold, heat the new air flowing through the cross-flow heat exchanger by the cooling coil.

[0082] In one embodiment of the present application, a hot water flow pipeline is connected to the cooling coil, and the cooling coil can be used to heat the new air flowing through it. Since the cross-flow heat exchanger is used to preheat the new air, when the first temperature data is less than 2°C, the new air heated by the cooling coil will enter the cross-flow heat exchanger, thereby preheating the new air entering the cross-flow heat exchanger to a temperature of 2°C or above, thereby avoiding cracking of the cooling coil.

[0083] S4: If the first temperature data is not less than the first temperature threshold, send the new air to the cooling coil and heat the new air by the cooling coil.

[0084] In one embodiment of the present application, when the first temperature data is greater than or equal to 2°C, i.e., within the range that the cooling coil can withstand, the new air is directly sent to the cooling coil for heating.

[0085] In one embodiment of the present application, with reference to Figure 3 After the new air flowing through the cross-flow heat exchanger is preheated by the cooling coil, the following steps can also be included:

[0086] S5: Collect the second temperature data of the new air at the air outlet of the cross-flow heat exchanger.

[0087] In one embodiment of the present application, a high-precision temperature sensor is installed at the air outlet of the cross-flow heat exchanger, and the second temperature data at the air outlet of the cross-flow heat exchanger is collected in real time by the high-precision temperature sensor.

[0088] S6: Determine whether the second temperature data is not less than the first temperature threshold.

[0089] In the present embodiment, determine whether the second temperature data collected in step S5 is not less than 2°C.

[0090] S7: If the second temperature data is not less than the first temperature threshold, the preheated fresh air is sent to the surface cooler, and the fresh air is heated by the surface cooler.

[0091] In an embodiment of the present application, when the second temperature data is greater than or equal to 2℃, the surface cooler can be prevented from being frozen, and then the preheated fresh air is sent to the surface cooler for heating.

[0092] S8: If the second temperature data is less than the first temperature threshold, the water valve opening degree of the surface cooler is increased, an alarm information is sent, and the fan and the fresh air sealing air valve are closed.

[0093] In an embodiment of the present application, when the second temperature data is less than 2℃, the water valve opening degree of the surface cooler can be increased to make a large amount of hot water flow into the surface cooler, so as to increase the temperature of the fresh air heated by the surface cooler, and then the temperature of the cross-flow heat exchanger can be increased to preheat the fresh air flowing through the cross-flow heat exchanger by a large temperature, at the same time, the fresh air unit sends an alarm information, and the fan and the fresh air sealing air valve are closed to prevent the surface cooler from being frozen.

[0094] In an embodiment of the present application, the second temperature data of the fresh air at the outlet of the cross-flow heat exchanger is collected, so as to further prevent the surface cooler from being frozen.

[0095] In an embodiment of the present application, the second temperature data of the fresh air at the outlet of the cross-flow heat exchanger is collected, so as to further prevent the surface cooler from being frozen. Figure 4 After the fresh air is heated by the surface cooler, the following steps can be further included:

[0096] S9: The heated fresh air is heated again by a heat exchanger.

[0097] In an embodiment of the present application, the heat exchanger is a first heat exchanger in the fresh air unit, and the heat exchanger is connected with a hot water pipeline, so as to heat the fresh air flowing through the heat exchanger again by the hot water pipeline.

[0098] S10: Third temperature data of the fresh air heated again is collected.

[0099] In an embodiment of the present application, a high-precision temperature sensor is installed at the outlet of the heat exchanger, and then the third temperature data of the fresh air heated again is collected by the high-precision temperature sensor in real time.

[0100] S11: Whether the third temperature data is not less than a second temperature threshold is judged.

[0101] In an embodiment of the present application, the second temperature threshold is a user set temperature, for example, any value in 25℃-28℃, and whether the third temperature data collected in step S10 is not less than the user set temperature is judged.

[0102] S12: If the third temperature data is not less than the second temperature threshold, increasing the blowing power of the fan, and blowing the newly heated fresh air to the indoor through the fan.

[0103] In one embodiment of the present application, when the third temperature data is greater than or equal to the user set temperature, the blowing power of the fan can be increased to increase the blowing amount of the fan, and then the newly heated fresh air is blown to the indoor through the fan.

[0104] S13: If the third temperature data is less than the second temperature threshold, increasing the heat supply temperature of the heat exchanger, and reducing the blowing power of the fan to blow the newly heated fresh air to the indoor through the fan.

[0105] In one embodiment of the present application, when the third temperature data is less than the user set temperature, the opening degree of the hot water management in the heat exchanger can be increased to increase the heat supply temperature of the heat exchanger, thereby increasing the temperature of the fresh air flowing through the heat exchanger, and reducing the blowing power of the fan to blow the newly heated fresh air to the indoor through the fan.

[0106] In one embodiment of the present application, referring to Figure 5 , the heat exchanger is provided with a heating coil, and the fresh air is re-heated by the heating coil. The heat exchanger in the present embodiment is the first heat exchanger in the above-mentioned fresh air handling unit, and specifically includes the following steps:

[0107] S14: Real-time monitoring of the tube temperature of the heating coil.

[0108] In one embodiment of the present application, a high-precision temperature sensor is installed on the heating coil, and the high-precision temperature sensor can be used to collect the tube temperature of the heating coil in real time.

[0109] S15: Switching the temperature control target according to the tube temperature and the preset freeze protection temperature threshold.

[0110] In one embodiment of the present application, the preset freeze protection temperature threshold is the lower limit value of the coil freeze protection temperature, and the preset freeze protection temperature threshold can be used to determine whether the heating coil is at risk of freeze cracking.

[0111] In one embodiment of the present application, referring to Figure 6 , step S15 specifically includes the following steps:

[0112] S151: Comparing the tube temperature with the preset freeze protection temperature threshold to determine the interval in which the tube temperature is located.

[0113] S152: Switching the temperature control target according to the determined interval.

[0114] In one embodiment of the present application, the temperature control target is switched by comparing the pipe body temperature with the preset freeze protection temperature threshold, so that the freeze protection of the coil and the temperature control can be considered.

[0115] In one embodiment of the present application, the temperature control target is switched by comparing the pipe body temperature with the preset freeze protection temperature threshold, so that the freeze protection of the coil and the temperature control can be considered. Figure 7 The step S152 specifically includes the following steps:

[0116] S1521: If the pipe body temperature is greater than or equal to the sum of the preset freeze protection temperature threshold and the preset value, and lasts for a preset time, switch to the first temperature control target, wherein the first temperature control target corresponds to the measured room temperature and the target temperature is the user set temperature.

[0117] S1522: If the pipe body temperature is less than or equal to the preset freeze protection temperature threshold, and lasts for a preset time, switch to the second temperature control target, wherein the second temperature control target corresponds to the measured pipe body temperature and the target temperature is the preset freeze protection temperature threshold.

[0118] S1523: If the pipe body temperature is greater than the preset freeze protection temperature threshold and less than the sum of the preset freeze protection temperature threshold and the preset value, and lasts for a preset time, keep the last determined temperature control target unchanged.

[0119] The preset time in the present embodiment can be set according to actual conditions, for example, the preset time can be set to any value in 3-60s, and thus by setting the preset time, false judgment can be avoided.

[0120] The preset value in the present embodiment can be set by debugging according to the scale and heat load characteristics of different fresh air handling units, for example, the preset value can be set to 0.5-5℃, and thus by setting the preset value to participate in the switching of the temperature control target, the temperature difference gradient between the fresh air handling unit and the room temperature can be ensured to be reasonable when the fresh air handling unit operates according to the second temperature control target, and the control accuracy of the fresh air handling unit on the room temperature is about ±2℃. If the temperature difference gradient is too small, the temperature control target switches frequently, resulting in unstable temperature control; if the temperature gradient is too large, the transition interval is too large, which easily leads to room temperature control lag. On the basis of ensuring smooth switching of the temperature control target, the smaller the preset value, the higher the temperature control accuracy.

[0121] Based on the intelligent switching of the temperature control target based on the pipe body temperature, the fresh air handling unit can be prevented from freezing in advance, and the protection shutdown caused by too small medium flow at low room load can be avoided, and the comfortable and accurate room temperature control can be realized according to the dynamic load change of the room temperature.

[0122] S16: Adjusting the medium flow of the heating coil according to the current temperature control target, so that the measured temperature corresponding to the current temperature control target reaches the target temperature.

[0123] In an embodiment of the present application, the temperature control target comprises a measured temperature and a target temperature corresponding to the measured temperature, the measured temperature is a measured value of the temperature parameter to be controlled, and the target temperature is a target value of the temperature parameter to be controlled. For example, the measured temperature is the room temperature, and the target temperature is the user-set temperature; or the measured temperature is the pipe body temperature of the heating coil, and the target temperature is a preset freeze protection temperature threshold.

[0124] The heating coil heats air through the heat medium, and by adjusting the heat medium flow of the heating coil, the pipe body temperature of the heating coil can be changed to achieve coil freeze protection, and the outlet air temperature of the fresh air handling unit can also be changed to regulate the room temperature.

[0125] In the heating operation, the pipe body temperature of the heating coil is monitored, the temperature control target is automatically switched according to the pipe body temperature and the preset freeze protection temperature threshold, and the medium flow of the heating coil is adjusted according to the current temperature control target, so that the measured temperature corresponding to the current temperature control target reaches the target temperature, which is the preset freeze protection temperature threshold or the user-set temperature. Combining the coil freeze protection control of the fresh air handling unit with the room temperature control, the heating coil automatically prevents freezing and automatically tracks the room temperature change, improves the temperature control precision on the basis of meeting the coil freeze protection, ensures the room temperature comfort, and solves the problems of more devices required for the coil freeze protection of the fresh air handling unit and poor temperature control precision of the fresh air handling unit.

[0126] In an embodiment of the present application, the temperature control target comprises a measured temperature and a target temperature corresponding to the measured temperature, the measured temperature is a measured value of the temperature parameter to be controlled, and the target temperature is a target value of the temperature parameter to be controlled. For example, the measured temperature is the room temperature, and the target temperature is the user-set temperature; or the measured temperature is the pipe body temperature of the heating coil, and the target temperature is a preset freeze protection temperature threshold. Figure 8 The heating coil is connected with a medium inflow pipeline, a heat supply control valve is arranged on the medium inflow pipeline, and the medium flow of the heating coil is adjusted according to the current temperature control target, which specifically includes the following steps:

[0127] S17: If the measured temperature is greater than the target temperature, the opening degree of the heat supply control valve is reduced.

[0128] S18: If the measured temperature is equal to the target temperature, the current opening degree of the heat supply control valve is maintained.

[0129] S19: If the measured temperature is less than the target temperature, the opening degree of the heat supply control valve is increased.

[0130] In an embodiment of the present application, the medium flow of the heating coil is adjusted by controlling the opening degree of the heat supply control valve, and the heat supply control valve in this embodiment is the second expansion valve of the fresh air handling unit.

[0131] Wherein, the medium flow of the heating coil is adjusted according to the current temperature control target, for example, the opening adjustment of the heat supply control valve is carried out through proportional integral control or proportional integral derivative control, and the opening of the heat supply control valve can be quickly adjusted in the embodiment, so as to adjust the medium flow of the heating coil.

[0132] Wherein, the conventional heat medium includes hot water and saturated 0.3MPa high-temperature steam, and the water medium is in the heating coil after heating, so the tube temperature of the heating coil is required to be greater than 0℃, and considering the safety margin, the preset anti-freezing protection temperature threshold is higher than 0℃, if the preset anti-freezing protection temperature threshold is set too small, the anti-freezing protection is likely to fail due to the too small opening of the heat supply control valve, and the room temperature control is not comfortable due to the too low supply air temperature; if the preset anti-freezing protection temperature threshold is set too large, the anti-freezing is not failed, but the room temperature control is not comfortable due to the too high supply air temperature when the room load is small.

[0133] Wherein, the preset anti-freezing protection temperature threshold in the embodiment can be set to any value in 3-45℃, and the preset anti-freezing protection temperature threshold is greater than or equal to the user set temperature-7℃ and less than or equal to the user set temperature+15℃, and in winter heating, the range of the user set temperature is generally 10-30℃, so the anti-freezing control and the room temperature control precision can be effectively considered.

[0134] Through the control method of the fresh air handling unit, the air temperature before entering the heating coil reaches above 3℃ by using the self-preheating technology of the fresh air handling unit, so the coil freezing can be effectively prevented, the fresh air handling unit uses 50-60℃ low-temperature hot water, and the fresh air demand under-22℃ outdoor environment temperature can be met, no electric heating preheating is needed, no anti-freezing liquid is needed, the equipment structure is simple, the installation and debugging are convenient, and the fresh air handling unit can be widely applied to office buildings, schools, exhibition halls, stadiums, theaters, libraries and hotel lobbies in severe cold and cold regions.

[0135] The fresh air handling unit can adapt to an extremely cold outdoor environment of-22 DEG C, and directly pass low-temperature hot water without freezing. The shell of the fresh air handling unit adopts an overall foamed sandwich structure, the outer plate is subjected to professional corrosion treatment, and the inner plate is a galvanized plate. The two layers of steel plates are filled with hard polyurethane thermal insulation material which has excellent waterproof and fireproof properties and excellent thermal insulation performance. The thermal insulation of the panel is high-pressure polyurethane foam with a density of 50 kg / m3, and the standard panel thickness is 30 mm. The fan adopts a low-noise direct-coupled outer rotor centrifugal fan, has the characteristics of double-sided air inlet, small volume, large air volume, stable operation, low noise, and high full pressure, and the like. The high-efficiency self-preheating core adopts a hydrophilic aluminum foil material and a 90 DEG cross-flow design. The air passage adopts a stamping convex circular body for support, and has high strength and fastening property. The self-preheating core can ensure that the temperature of the preheated fresh air is higher than 3 DEG C, meeting the anti-freezing requirement. Two-stage low-temperature hot water heaters are adopted. In the case of an outdoor temperature of-22 DEG C in winter, the supply air temperature can reach 24 DEG C, and the indoor equipment does not need to bear the fresh air load. The fresh air handling unit can be optionally provided with an electrode steam humidifier to meet the winter humidification requirement. The fresh air handling unit adopts an intelligent PLC liquid crystal control screen, adopts an RS485 communication mode, supports a modbus communication protocol, and can realize functions such as hot water valve regulation and control, temperature monitoring, fresh air damper and fan control, connection to building automatic control, and the like.

[0136] In an embodiment of the present application, the intelligent PLC liquid crystal control screen can adjust the heat exchanger water valve opening degree in real time according to the supply air temperature, can set an intelligent timing operation mode and a holiday mode, and can realize a filter screen timing alarm reminding function.

[0137] The implementation principle of the embodiment of the present application is that the temperature at the inlet of the cross-flow heat exchanger is monitored in real time, it is judged whether the temperature at the inlet is less than a preset temperature threshold, and when the temperature at the inlet is less than the preset temperature threshold, the heat supply of the surface cooler is used to heat the fresh air flowing through the cross-flow heat exchanger, and then the cross-flow heat exchanger is used to preheat the fresh air, so as to improve the temperature of the fresh air, thereby avoiding the surface cooler from being frozen and cracked by the low-temperature fresh air.

[0138] The embodiment of the present application discloses a control system of a fresh air handling unit, referring to Figure 9 , comprising an acquisition module 4, a judgment module 5, a first execution module 6, and a second execution module 7. The first temperature data of the fresh air at the inlet of the cross-flow heat exchanger is acquired by means of the acquisition module 4. It is judged by means of the judgment module 5 whether the first temperature data is less than a first temperature threshold. When the first temperature data is less than the first temperature threshold, the fresh air flowing through the cross-flow heat exchanger is preheated by means of the heat supply of the surface cooler by means of the first execution module 6. When the first temperature data is not less than the first temperature threshold, the fresh air is sent to the surface cooler, and the fresh air is heated by means of the surface cooler by means of the second execution module 7.

[0139] The control system of the fresh air handling unit in the embodiment is applied with the control method of the fresh air handling unit in the above embodiment, and thus the specific content of the control system of the fresh air handling unit is not described herein.

[0140] The embodiment of the present application discloses a terminal, comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor loads the computer program to execute the control method of the fresh air handling unit in the above embodiment.

[0141] In one embodiment of the present application, the terminal can be a desktop computer, a notebook computer or a cloud server, and the terminal comprises but is not limited to a processor and a memory, for example, the terminal can also comprise an input / output device, a network access device and a bus.

[0142] In one embodiment of the present application, the processor can be a central processing unit (CPU), and of course, according to the actual use case, other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), off-the-shelf programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. can also be used, and the general-purpose processor can be a microprocessor or any conventional processor, etc. The present application does not make any limitation in this regard.

[0143] In one embodiment of the present application, the memory can be an internal storage unit of the terminal, for example, a hard disk or a memory of the terminal, or an external storage device of the terminal, for example, a plug-in hard disk, a smart memory card (SMC), a secure digital card (SD) or a flash memory card (FC) equipped on the terminal, and the memory can also be a combination of the internal storage unit and the external storage device of the terminal. The memory is used to store computer programs and other programs and data required by the terminal, and the memory can also be used to temporarily store data that has been output or will be output. The present application does not make any limitation in this regard.

[0144] By setting the terminal, the control method of the fresh air handling unit in the above embodiment is stored in the memory of the terminal and loaded and executed on the processor of the terminal, so that the user can establish contact with the system through the terminal and query the processed contents of the system.

[0145] The embodiment of the present application discloses a computer readable storage medium, and the computer readable storage medium stores a computer program, wherein the computer program is loaded by the processor to execute the control method of the fresh air handling unit in the above embodiment.

[0146] In an embodiment of the present application, the computer program can be stored in a computer readable storage medium, and the computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form of these. The computer readable storage medium includes any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, software distribution medium, and the like. It should be noted that the computer readable storage medium includes but is not limited to the above-mentioned components.

[0147] By means of the computer readable storage medium, the control method of the fresh air handling unit in the above embodiment is stored in the computer readable storage medium and loaded and executed on the processor. After the computer readable storage medium is loaded into any computer, the computer can execute the control method of the fresh air handling unit in the above embodiment.

[0148] The embodiments of the specific implementation are the preferred embodiments of the present application, but not limit the protection scope of the present application. The same components are indicated by the same reference numerals. Therefore, equivalent changes made according to the structure, shape, principle of the present application should be covered by the protection scope of the present application.

Claims

1. A control method for a fresh air handling unit, characterized in that, include: Collect the first temperature data of the fresh air at the air inlet of the cross-flow heat exchanger; Determine whether the first temperature data is less than the first temperature threshold. If the first temperature data is less than the first temperature threshold, then the fresh air flowing through the cross-flow heat exchanger is preheated by supplying heat through the surface cooler. If the first temperature data is not less than the first temperature threshold, then fresh air is sent to the surface cooler and heated by the surface cooler; After the fresh air is heated by the aforementioned surface cooler, the system further includes: The heated fresh air is reheated using a heat exchanger; Collect the third temperature data of the fresh air after reheating; Determine whether the third temperature data is not less than the second temperature threshold; If the third temperature data is not less than the second temperature threshold, then increase the blowing power of the fan and blow the reheated fresh air into the room through the fan; If the third temperature data is less than the second temperature threshold, the heating temperature of the heat exchanger is increased and the blowing power of the fan is reduced so that the reheated fresh air is blown into the room through the fan. The heat exchanger is equipped with a heating coil, which reheats the fresh air. Specifically, this includes: Real-time monitoring of the tube temperature of the heating coil; The temperature control target is switched according to the tube temperature and the preset antifreeze protection temperature threshold. Based on the current temperature control target, adjust the medium flow rate of the heating coil so that the measured temperature corresponding to the current temperature control target reaches the target temperature; The step of switching the temperature control target based on the pipe body temperature and the preset antifreeze protection temperature threshold specifically includes: The temperature of the tube body is compared with the preset antifreeze protection temperature threshold to determine the range of the tube body temperature. Based on the determined range, switch the temperature control target; The step of switching the temperature control target according to the determined interval specifically includes: If the temperature of the tube body is greater than or equal to the sum of the preset antifreeze protection temperature threshold and the preset value, and continues for a preset time, then switch to the first temperature control target, wherein the measured temperature corresponding to the first temperature control target is the room temperature, and the target temperature is the user-set temperature; If the tube temperature is less than or equal to the preset antifreeze protection temperature threshold and continues for a preset time, then switch to the second temperature control target, wherein the measured temperature corresponding to the second temperature control target is the tube temperature, and the target temperature is the preset antifreeze protection temperature threshold; If the temperature of the tube body is greater than the preset antifreeze protection temperature threshold and less than the sum of the preset antifreeze protection temperature threshold and the preset value, and this condition persists for a preset time, then the most recently determined temperature control target will remain unchanged.

2. The control method for the fresh air handling unit according to claim 1, characterized in that, After preheating the fresh air flowing through the cross-flow heat exchanger by supplying heat through the surface cooler, the process further includes: Collect the second temperature data of the fresh air at the outlet of the cross-flow heat exchanger; Determine whether the second temperature data is not less than the first temperature threshold; If the second temperature data is not less than the first temperature threshold, the preheated fresh air is sent to the surface cooler and heated by the surface cooler. If the second temperature data is less than the first temperature threshold, the opening of the water valve of the surface cooler is increased, an alarm message is issued, and the fan and the fresh air sealing valve are shut off.

3. The control method for the fresh air handling unit according to claim 1, characterized in that, The heating coil is connected to a medium inflow pipeline, and a heating control valve is installed on the medium inflow pipeline. The medium flow rate of the heating coil is adjusted according to the current temperature control target, specifically including: If the measured temperature is greater than the target temperature, then reduce the opening of the heating control valve; If the measured temperature is equal to the target temperature, then maintain the current opening of the heating control valve; If the measured temperature is lower than the target temperature, the opening of the heating control valve is increased.

4. A control system for a fresh air handling unit, characterized in that, The control method for the fresh air handling unit according to any one of claims 1-3 is adopted, the system comprising: The data acquisition module (4) is used to acquire the first temperature data of the fresh air at the air inlet of the crossflow heat exchanger; The judgment module (5) is used to determine whether the first temperature data is less than the first temperature threshold. The first execution module (6) is used to preheat the fresh air flowing through the cross-flow heat exchanger by supplying heat through the surface cooler when the first temperature data is less than the first temperature threshold. The second execution module (7) is used to send fresh air to the surface cooler when the first temperature data is not less than the first temperature threshold, and to heat the fresh air through the surface cooler.

5. A terminal, comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that, When the processor loads the computer program, it executes the method according to any one of claims 1-3.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is loaded by the processor, it executes the method of any one of claims 1-3.

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