Evaporative cooling chiller and control method thereof

Abstract

The present invention relates to the technical field of air conditioning equipment, and in particular to an evaporative cooling chiller and a control method thereof. The evaporative cooling chiller of the present invention comprises: a unit housing, a surface cooler, an evaporative cooling coil device and a fan. A first air duct and a second air duct separated from each other are arranged in the unit housing. The two ends of the first air duct are respectively connected to the air inlet and the air outlet. The surface cooler and the cooling coil device are arranged in the first air duct and are sequentially located between the air outlet and the air inlet. The air inlet end of the second air duct is connected to the air inlet in an opening and closing manner through a first air valve. The air outlet end of the second air duct is connected to the part of the first air duct located between the surface cooler and the evaporative cooling coil device in an opening and closing manner through a second air valve. The air outlet end of the second air duct is connected to the part of the first air duct located between the fan and the surface cooler in an opening and closing manner through a third air valve. In the present invention, the air flow path can be controlled by adjusting the air valve, thereby reducing wind resistance and reducing fan energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning equipment, and in particular to an evaporative cooling chiller and a control method thereof. Background Art

[0002] With the continuous development and deepening of evaporative cooling air-conditioning technology, various forms of evaporative cooling chillers have emerged and play a good role in energy saving and environmental protection in actual projects.

[0003] In the prior art, in the evaporative cooling chiller with natural cooling function, in its cooling mode, the air needs to pass through the heat exchange tube group, the surface cooler, the filler and other components. The wind resistance of the unit is large, resulting in high fan energy consumption and low system energy efficiency, which greatly reduces the energy saving of the evaporative cooling chiller with natural cooling function. Summary of the invention

[0004] The present invention provides an evaporative cooling chiller and a control method thereof, which are used to solve at least one of the above technical problems.

[0005] One aspect of the present invention provides an evaporative cooling chiller, comprising: a unit housing, a surface cooler, an evaporative cooling coil device and a fan, wherein an air inlet and an air outlet are respectively arranged on opposite sides of the unit housing, and the fan is arranged at the air outlet.

[0006] The unit housing is provided with a first air duct and a second air duct separated from each other, the two ends of the first air duct are respectively connected to the air inlet and the air outlet, the surface cooler and the cooling coil device are arranged in the first air duct and are located in sequence between the air outlet and the air inlet,

[0007] The air inlet end of the second air duct is connected to the air inlet in an open-closeable manner through a first air valve.

[0008] The air outlet end of the second air duct is connected to the part of the first air duct located between the surface cooler and the evaporative cooling coil device in an openable and closeable manner through a second air valve.

[0009] The air outlet end of the second air duct is connected to a portion of the first air duct located between the fan and the surface cooler in an openable and closable manner through a third air valve.

[0010] In one embodiment, the first air duct is disposed at the center of the unit housing and extends in a vertical direction, and the second air duct is disposed around the first air duct and extends in a vertical direction.

[0011] In one embodiment, a controller is also included.

[0012] The controller is connected to the fan to control the frequency of the fan;

[0013] The controller is connected to the first air valve, the second air valve and the third air valve respectively to control the states of the first air valve, the second air valve and the third air valve.

[0014] In one embodiment, a temperature sensing package for measuring the ambient dry-bulb temperature is provided on the outer wall of the unit housing.

[0015] In one embodiment, the evaporative cooling coil device comprises: a water tank, a spray assembly, a heat exchange tube group and a filler.

[0016] The spray assembly, the heat exchange tube group and the filler are arranged in sequence from top to bottom in the first air duct, the water tank is arranged below the filler, and the water tank is connected to the spray assembly through a water supply pipeline.

[0017] In one embodiment, a first temperature sensor is provided at the inlet end of the heat exchange tube group, and the first temperature sensor is used to measure the inlet temperature of the refrigerant passing into the heat exchange tube group;

[0018] A second temperature sensor is provided at the outlet end of the heat exchange tube group, and the second temperature sensor is used to measure the outlet temperature of the refrigerant passing into the heat exchange tube group.

[0019] In one embodiment, a water pump, a ball valve and a one-way valve are sequentially arranged on the water supply pipeline.

[0020] In one embodiment, a third temperature sensor is provided at the inlet of the surface cooler, and the third temperature sensor is used to measure the inlet temperature of the coolant passing into the surface cooler;

[0021] A fourth temperature sensor is provided at the outlet of the surface cooler, and the fourth temperature sensor is used to measure the outlet temperature of the coolant passing into the surface cooler.

[0022] Another aspect of the present invention provides a control method for an evaporative cooling chiller, which is used to control the above evaporative cooling chiller, comprising:

[0023] Activate the corresponding cooling mode according to the range of ambient dry-bulb temperature; and

[0024] Adjust the states of the first air valve, the second air valve and the third air valve according to the corresponding cooling mode to control the flow path of air from the air inlet to the air outlet, thereby achieving the purpose of reducing wind resistance;

[0025] Wherein, the refrigeration mode includes: natural refrigeration mode, mechanical refrigeration mode and mixed refrigeration mode. In the natural refrigeration mode, the refrigerant is cooled by the surface cooler;

[0026] In mechanical cooling mode, the refrigerant is cooled by an evaporative cooling coil unit;

[0027] In hybrid cooling mode, the secondary coolant is cooled by the surface cooler and the refrigerant is cooled by the evaporative cooling coil unit at the same time.

[0028] In one embodiment, the steps include:

[0029] Step 11: If the ambient dry-bulb temperature is less than or equal to the first preset temperature, the natural cooling mode is started;

[0030] Step 12: In the natural cooling mode, the first air valve and the second air valve are controlled to be fully opened, and the third air valve is closed;

[0031] Step 13: Determine the range of the inlet and outlet temperature difference of the coolant. If it is within the first temperature difference range, keep the frequency of the fan unchanged; if it is within the second temperature difference range, execute step 14; if it is within the third temperature difference range, execute step 15;

[0032] Step 14: adjusting the frequency of the fan according to the first preset method, and then returning to step 13;

[0033] Step 15: Adjust the frequency of the fan according to the second preset method, and then return to step 13.

[0034] In one embodiment, the steps include:

[0035] Step 21: If the ambient dry-bulb temperature is greater than or equal to the second preset temperature, start the mechanical cooling mode;

[0036] Step 22: In the mechanical cooling mode, the first air valve is controlled to be closed, and the second air valve and the third air valve are controlled to be fully opened;

[0037] Step 23: Determine the range of the refrigerant inlet and outlet enthalpy difference. If it is within the first enthalpy difference range, keep the fan frequency unchanged; if it is within the second enthalpy difference range, execute step 24; if it is within the third enthalpy difference range, execute step 25;

[0038] Step 24: adjusting the frequency of the fan according to the third preset method, and then returning to step 23;

[0039] Step 25: Adjust the frequency of the fan according to the fourth preset method, and then return to step 23.

[0040] In one embodiment, the steps include:

[0041] Step 31: If the ambient dry-bulb temperature is between the first preset temperature and the second preset temperature, the hybrid cooling mode is started;

[0042] Step 32: Control the first air valve, the second air valve and the third air valve to close in the mixed cooling mode;

[0043] Step 33: Determine the range of the refrigerant inlet and outlet enthalpy difference. If it is in the first enthalpy difference range, keep the fan frequency unchanged and execute step 36; if it is in the second enthalpy difference range, execute step 34; if it is in the third enthalpy difference range, execute step 35;

[0044] Step 34: adjusting the frequency of the fan according to the third preset method, and returning to step 33;

[0045] Step 35: adjusting the frequency of the fan according to the fourth preset method, and returning to step 33;

[0046] Step 36: Determine the range of the inlet and outlet temperature difference of the coolant. If it is in the first temperature difference range, keep the frequency of the fan unchanged; if it is in the second temperature difference range, execute step 37; if it is in the third temperature difference range, execute step 38;

[0047] Step 37: fully open the first air valve, and increase the opening of the second air valve according to the fifth preset method, and then return to step 33;

[0048] Step 38: Fully open the second air valve, and increase the opening of the third air valve according to the sixth preset method, and then return to step 33.

[0049] Compared with the prior art, the advantages of the present invention are as follows: in the present invention, the first air duct and the second air duct are respectively arranged in the unit shell so that there are multiple options for the flow path of air from the air inlet to the air outlet, and the flow path of the air can be controlled by adjusting the states of the first air valve, the second air valve and the third air valve. Different paths can be selected for air circulation in different refrigeration modes, thereby reducing the wind resistance under the corresponding refrigeration model and reducing the energy consumption of the fan, which is beneficial to improving the energy saving of the evaporative cooling chiller. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0051] Figure 1 is a schematic structural diagram of an evaporative cooling chiller in one embodiment of the present invention;

[0052] Figure 2 is a schematic diagram of cooling mode switching steps in one embodiment of the present invention;

[0053] Figure 3 is a schematic diagram of control steps in a natural cooling mode in an embodiment of the present invention;

[0054] Figure 4It is a schematic diagram of control steps in a mechanical refrigeration mode in an embodiment of the present invention.

[0055] Figure 5 It is a schematic diagram of control steps in a mechanical refrigeration mode in an embodiment of the present invention.

[0056] Reference numerals:

[0057] 1-unit housing; 2-surface cooler; 3-fan; 4-air inlet; 5-air outlet;

[0058] 6-first air duct; 7-second air duct; 8-first air valve; 9-second air valve; 10-third air valve;

[0059] 11-controller; 12-temperature sensing package; 13-water tank; 14-spray assembly; 15-heat exchange tube group;

[0060] 16-filler; 17-water supply pipeline; 18-first temperature sensor; 19-second temperature sensor;

[0061] 20-third temperature sensor; 21-fourth temperature sensor; 22-water pump; 23-ball valve;

[0062] 24 - one-way valve; 25 - first pressure sensor; 26 - second pressure sensor. DETAILED DESCRIPTION

[0063] The present invention will be further described below in conjunction with the accompanying drawings.

[0064] like Figure 1 As shown in the figure, the evaporative cooling chiller of the present invention comprises: a unit housing 1, a surface cooler 2, an evaporative cooling coil device and a fan 3. Among them, an air inlet 4 and an air outlet 5 are respectively arranged on opposite sides of the unit housing 1, and the fan 3 is arranged at the air outlet 5. A first air duct 6 and a second air duct 7 separated from each other are arranged in the unit housing 1, and both ends of the first air duct 6 are respectively connected to the air inlet 4 and the air outlet 5, the surface cooler 2 and the cooling coil device are arranged in the first air duct 6 and are sequentially located between the air outlet 5 and the air inlet 4, the air inlet end of the second air duct 7 is connected to the air inlet 4 in an opening and closing manner through a first air valve 8, the air outlet end of the second air duct 7 is connected to the part of the first air duct 6 located between the surface cooler 2 and the evaporative cooling coil device in an opening and closing manner through a second air valve 9, and the air outlet end of the second air duct 7 is connected to the part of the first air duct 6 located between the fan 3 and the surface cooler 2 in an opening and closing manner through a third air valve 10.

[0065] It should be noted that the evaporative cooling chiller of the present invention has a natural cooling function, and its cooling modes include: a natural cooling mode, a mechanical cooling mode and a mixed cooling mode.

[0066] In the natural cooling mode, the refrigerant is used for cooling, and the high-temperature refrigerant after cooling is passed into the surface cooler 2 for cooling.

[0067] In the mechanical refrigeration mode, refrigeration is carried out through the refrigerant. The high-temperature refrigerant after refrigeration is compressed by the compressor into a high-temperature and high-pressure gas and passed into the evaporative cooling coil device for cooling.

[0068] In the mixed cooling mode, cooling is performed by both the coolant and the refrigerant. The high-temperature refrigerant and the high-temperature coolant are respectively introduced into the corresponding surface cooler 2 and cooled by the evaporative cooling coil device.

[0069] In the present invention, a first air duct 6 and a second air duct 7 are respectively arranged in the unit shell 1 so that there are multiple options for the flow path of air from the air inlet 4 to the air outlet 5, and the flow path of the air can be controlled by adjusting the states of the first air valve 8, the second air valve 9 and the third air valve 10. Different paths can be selected for air circulation in different refrigeration modes, thereby reducing the wind resistance under the corresponding refrigeration model and reducing the energy consumption of the fan 3, which is beneficial to improving the energy saving of the evaporative cooling chiller.

[0070] Preferably, the first air duct 6 is arranged in the center of the unit housing 1 and extends in the vertical direction, and the second air duct 7 is arranged around the first air duct 6 and extends in the vertical direction. In this way, the air ducts in the unit housing 1 are arranged reasonably, which is conducive to achieving the connection between the second air duct 7 and the first air duct 6 and the uniform circulation of air.

[0071] Among them, the number of the first air valve 8, the second air valve 9 and the third air valve 10 can be set to one or more, preferably set to two, and multiple first air valves 8, second air valves 9 and third air valves 10 are evenly arranged on both sides of the first air duct 6, so that the air can circulate more evenly in the unit casing 1.

[0072] Specifically, the evaporative cooling chiller further includes a controller 11. The controller 11 is connected to the fan 3 to control the frequency of the fan 3. The controller 11 is respectively connected to the first air valve 8, the second air valve 9 and the third air valve 10 to control the states of the first air valve 8, the second air valve 9 and the third air valve 10.

[0073] The states of the first air valve 8, the second air valve 9 and the third air valve 10 include the opening and closing states and the opening sizes of the air valves.

[0074] In one embodiment, a temperature sensing package 12 for measuring the ambient dry bulb temperature is provided on the outer wall of the unit housing 1. The dry bulb temperature is the actual temperature of the air in contact with the surface of the bulb, and has nothing to do with the humidity in the air. The ambient dry bulb temperature is measured by the temperature sensing package 12, and the cooling mode is switched according to the range of the ambient dry bulb temperature, so that the control of the unit is more accurate.

[0075] In one embodiment, the evaporative cooling coil device includes: a water tank 13, a spray assembly 14, a heat exchange tube group 15 and a filler 16. Figure 1 As shown in the figure, the spray assembly 14, the heat exchange tube group 15 and the filler 16 are arranged in sequence from top to bottom in the first air duct 6, the water tank 13 is arranged below the filler 16, and the water tank 13 is connected to the spray assembly 14 through the water supply pipeline 17.

[0076] The operation process of the evaporative cooling coil device is as follows: the circulating water in the water tank 13 is sprayed on the heat exchange tube group 15 through the water supply pipe 17 and the spray assembly 14 to exchange heat with the high-temperature refrigerant in the heat exchange tube. The circulating water evaporates and takes away the heat, so that the refrigerant condenses in the heat exchange tube group 15. The circulating water is sprayed from top to bottom, spreads on the surface of the heat exchange tube group 15 to form a film, and absorbs the heat of the refrigerant in the heat exchange tube group 15. The circulating water is heated and the temperature rises (absorbs the heat of the refrigerant in the heat exchange tube group 15). A small part of the circulating water evaporates to form water vapor and is discharged from the condenser with the air. The remaining circulating water spreads on the filler 16 to form a film, a small part of the circulating water absorbs heat and evaporates and mixes with the air (the heat absorbed by evaporation is used to cool the circulating water), and the remaining other part of the circulating water is cooled and finally drips into the water tank 13, and then sent to the spray assembly 14.

[0077] It should be noted that a portion of the circulating water will be discharged from the fan 3 after evaporation, which will cause water vapor loss. Usually, a water replenishment port is provided in the water tank 13 to compensate for the circulating water loss.

[0078] Specifically, a first temperature sensor 18 is provided at the inlet end of the heat exchange tube group 15, and the first temperature sensor 18 is used to measure the inlet temperature of the refrigerant passing into the heat exchange tube group 15. A second temperature sensor 19 is provided at the outlet end of the heat exchange tube group 15, and the second temperature sensor 19 is used to measure the outlet temperature of the refrigerant passing into the heat exchange tube group 15. The inlet and outlet temperature difference of the refrigerant can be calculated by the outlet temperature and the inlet temperature of the refrigerant, and then the inlet and outlet enthalpy difference and the heat exchange amount of the refrigerant can be obtained.

[0079] In addition, a first pressure sensor 25 is provided at the inlet end of the heat exchange tube group 15, and the first pressure sensor 25 is used to measure the inlet pressure of the refrigerant passing into the heat exchange tube group 15. A second pressure sensor 26 is provided at the outlet end of the heat exchange tube group 15, and the second pressure sensor 26 is used to measure the outlet pressure of the refrigerant passing into the heat exchange tube group 15.

[0080] Preferably, a water pump 22, a ball valve 23 and a one-way valve 24 are sequentially arranged on the water supply pipeline 17. The water pump 22 is used to pump the circulating water in the water tank 13 to the spray assembly 14, the ball valve 23 is used to control the opening and closing of the water supply pipeline 17, and the one-way valve 24 is used to prevent the circulating water from flowing back into the water tank 13.

[0081] In one embodiment, a third temperature sensor 20 is provided at the inlet of the cooler 2, and the third temperature sensor 20 is used to measure the inlet temperature of the coolant passing into the cooler 2. A fourth temperature sensor 21 is provided at the outlet of the cooler 2, and the fourth temperature sensor 21 is used to measure the outlet temperature of the coolant passing into the cooler 2. The inlet and outlet temperature difference of the coolant can be calculated by the outlet temperature and inlet temperature of the coolant.

[0082] Preferably, the surface cooler 2 is a V-shaped surface cooler.

[0083] like Figure 2-5 As shown in the figure, the present invention also provides a control method for an evaporative cooling chiller, which is used to control the above-mentioned evaporative cooling chiller, including: starting a corresponding refrigeration mode according to the range of the ambient dry-bulb temperature; and adjusting the states of the first air valve 8, the second air valve 9 and the third air valve 10 according to the corresponding refrigeration mode to control the flow path of air from the air inlet 4 to the air outlet 5, thereby achieving the purpose of reducing wind resistance.

[0084] The refrigeration modes include: natural refrigeration mode, mechanical refrigeration mode and mixed refrigeration mode. In the natural refrigeration mode, the coolant is cooled by the surface cooler 2; in the mechanical refrigeration mode, the refrigerant is cooled by the evaporative cooling coil device; in the mixed refrigeration mode, the coolant is cooled by the surface cooler 2 and the refrigerant is cooled by the evaporative cooling coil device at the same time.

[0085] In the present invention, the refrigeration mode is switched reasonably according to the ambient dry-bulb temperature, so that reasonable application in different seasons can be achieved, especially in transitional seasons, so that the natural cold source can be fully utilized to achieve the purpose of energy saving.

[0086] At the same time, a first air duct 6 and a second air duct 7 are respectively arranged in the unit shell 1 so that there are multiple options for the flow path of air from the air inlet 4 to the air outlet 5, and the flow path of the air can be controlled by adjusting the states of the first air valve 8, the second air valve 9 and the third air valve 10. Different paths can be selected for air circulation in different refrigeration modes, thereby reducing the wind resistance under the corresponding refrigeration model and reducing the energy consumption of the fan 3, which is beneficial to improving the energy saving of the evaporative cooling chiller.

[0087] The start-up conditions of the natural cooling mode and the control steps in the natural cooling mode are described in detail below.

[0088] like Figure 3 As shown in , the control method of the evaporative cooling chiller includes the following steps:

[0089] Step 11: If the ambient dry-bulb temperature is less than or equal to the first preset temperature, the natural cooling mode is started.

[0090] Among them, in step 11, the ambient dry-bulb temperature T is detected by the temperature sensing bulb 12. The first preset temperature A1 can be set to 0 °C or other temperature values set by the user.

[0091] Step 12: Control the first air valve 8 and the second air valve 9 to be fully open and the third air valve 10 to be closed in the natural refrigeration mode.

[0092] Among them, the first air valve 8 and the second air valve 9 being fully open means that the opening degrees of the first air valve 8 and the second air valve 9 reach the maximum.

[0093] In the natural refrigeration mode, only the coolant is cooled by the surface cooler 2, and the evaporative cooling coil device is not operating. Through step 12, most of the air flowing in from the air inlet 4 directly flows through the second air duct 7 to the lower part of the surface cooler 2, and then directly flows out from the air outlet 5 after passing through the surface cooler 2, without passing through components such as the packing 16 and the heat exchange tube group 15 of the evaporative cooling coil device, thereby reducing the air resistance.

[0094] Step 13: Judge the range of the temperature difference between the inlet and outlet of the coolant. If it is within the first temperature difference range, keep the frequency of the fan 3 unchanged; if it is within the second temperature difference range, execute step 14; if it is within the third temperature difference range, execute step 15.

[0095] Step 14: Adjust the frequency of the fan 3 according to the first preset method, and then return to execute step 13.

[0096] Step 15: Adjust the frequency of the fan 3 according to the second preset method, and then return to execute step 13.

[0097] In steps 13 to 15, it is judged whether the current heat exchange amount meets the requirements according to the temperature difference ΔT1 between the inlet and outlet of the coolant. If it meets the requirements, keep the frequency of the fan 3 unchanged; if it does not meet the requirements, adjust the frequency of the fan 3 to adjust the heat exchange amount, so as to ensure the cooling demand of the coolant and avoid the frequency of the fan 3 from being too large, achieving the purpose of energy conservation and consumption reduction.

[0098] Specifically, in step 13, the first temperature difference range for the temperature difference between the inlet and outlet of the coolant is: B1 ≤ ΔT1 ≤ B2; the second temperature difference range for the temperature difference ΔT1 between the inlet and outlet of the coolant is ΔT1 < B1; the third temperature difference range for the temperature difference ΔT1 between the inlet and outlet of the coolant is: ΔT1 > B2. Among them, the values of B1 and B2 can be set by the user according to actual needs. For example, B1 can be set to 3.5 (°C) and B2 can be set to 7 (°C).

[0099] In step 14, adjusting the frequency of the fan 3 according to the first preset method specifically means: making the adjusted frequency M of the fan 3 in the natural refrigeration mode satisfy the following defining formula:

[0100] M = M O+z1|ΔT1-B1|.

[0101] In step 15, the frequency of the fan 3 is adjusted according to the second preset method, specifically: the frequency M' of the fan 3 after adjustment in the natural cooling mode satisfies the following definition:

[0102] M=M O -z1|B2-ΔT1|.

[0103] Where M O is the initial frequency of fan 3 in natural cooling mode, which is generally 40 (Hz); z1 is the correction factor, dimensionless unit, generally taking an empirical value, such as 1.2.

[0104] In other words, when the inlet and outlet temperature difference of the refrigerant is within the first temperature difference range, the frequency of fan 3 is within an appropriate range, which can not only ensure the heat exchange requirements of the refrigerant, but also does not cause energy waste; when the inlet and outlet temperature difference of the refrigerant is small (within the second temperature difference range), the frequency of fan 3 can be increased to meet the heat exchange requirements of the refrigerant; when the inlet and outlet temperature difference of the refrigerant is large (within the third temperature difference range), the frequency of fan 3 can be reduced to achieve energy saving and consumption reduction.

[0105] The start-up conditions of the mechanical cooling mode and the control steps in the mechanical cooling mode are described in detail below.

[0106] like Figure 4 As shown in , the control method of the evaporative cooling chiller includes the following steps:

[0107] Step 21: If the ambient dry-bulb temperature is greater than or equal to the second preset temperature, the mechanical cooling mode is started.

[0108] In step 21, the ambient dry-bulb temperature T is detected by the temperature sensing package 12, and the second preset temperature A2 can be set to 15°C or other temperature values ​​set by the user.

[0109] Step 22: In the mechanical refrigeration mode, the first air valve 8 is controlled to be closed, and the second air valve 9 and the third air valve 10 are controlled to be fully opened.

[0110] The second air valve 9 and the third air valve 10 being fully open means that the opening degrees of the second air valve 9 and the third air valve 10 are at the maximum.

[0111] In the mechanical refrigeration mode, the refrigerant is cooled only by the evaporative cooling coil device, and the surface cooler 2 is not in operation. Through step 22, most of the air flowing in from the air inlet 4 directly flows through the evaporative cooling coil device through the inlet end of the first air duct 6, and most of the air passing through the evaporative cooling coil device passes through the second air valve 9 and the third air valve 10 in sequence and then flows out from the air outlet 5, thereby bypassing the surface cooler 2 and reducing the wind resistance.

[0112] Step 23: Determine the range in which the enthalpy difference between the inlet and outlet of the refrigerant lies. If it is within the first enthalpy difference range, keep the frequency of the fan 3 unchanged; if it is within the second enthalpy difference range, execute Step 24; if it is within the third enthalpy difference range, execute Step 25.

[0113] Step 24: Adjust the frequency of the fan 3 in accordance with the third preset method, and then return to execute Step 23;

[0114] Step 25: Adjust the frequency of the fan 3 in accordance with the fourth preset method, and then return to execute Step 23.

[0115] In Steps 23 to 25, it is determined whether the current heat exchange amount of the refrigerant meets the requirements based on the enthalpy difference ΔH between the inlet and outlet of the refrigerant. If it meets the requirements, keep the frequency of the fan 3 unchanged; if it does not meet the requirements, adjust the heat exchange amount by adjusting the frequency of the fan 3, so as to ensure the cooling demand of the refrigerant and avoid excessive frequency of the fan 3, achieving the purpose of energy conservation and consumption reduction.

[0116] At the same time, since the pressure and temperature of the refrigerant will change greatly after flowing through the heat exchange tube group 15 for heat exchange, and there is a certain functional relationship between the enthalpy value of the refrigerant and its temperature and pressure, the heat exchange amount of the refrigerant is determined by the enthalpy difference between the inlet and outlet of the refrigerant.

[0117] Specifically, in Step 23, the first enthalpy difference range for the enthalpy difference ΔH between the inlet and outlet of the refrigerant is: C1 ≤ ΔH ≤ C2; the second enthalpy difference range for the enthalpy difference ΔH between the inlet and outlet of the refrigerant is ΔH < C1; the third enthalpy difference range for the enthalpy difference ΔH between the inlet and outlet of the refrigerant is: ΔH > C2. Among them, the values of C1 and C2 can be set by the user according to actual needs. For example, C1 can be set to 140 (kJ / kg) and C2 can be set to 175 (kJ / kg).

[0118] In Step 24, adjusting the frequency of the fan 3 in accordance with the third preset method specifically means: making the adjusted frequency M' of the fan 3 in the mechanical refrigeration mode satisfy the following defining formula:

[0119] M' = M' O + z2|ΔH - C1|.

[0120] In Step 25, adjusting the frequency of the fan 3 in accordance with the fourth preset method specifically means: making the adjusted frequency M' of the fan 3 in the mechanical refrigeration mode satisfy the following defining formula:

[0121] M' = M' O - z2|C2 - ΔH|.

[0122] In the formula, M' Ois the initial frequency of fan 3 in mechanical refrigeration mode, which is generally 35 (Hz); z2 is a correction factor, a dimensionless unit, which is generally an empirical value, such as 1.1.

[0123] In other words, when the inlet and outlet enthalpy difference of the refrigerant is in the first enthalpy difference range, the frequency of the fan 3 is in an appropriate range, which can not only ensure the heat exchange requirements of the refrigerant, but also will not cause energy waste; when the inlet and outlet enthalpy difference of the refrigerant is small (in the second enthalpy difference range), the frequency of the fan 3 can be increased to meet the heat exchange requirements of the coolant; when the inlet and outlet temperature difference of the coolant is large (in the third enthalpy difference range), the frequency of the fan 3 can be reduced to achieve energy saving and consumption reduction.

[0124] The start-up conditions of the hybrid cooling mode and the control steps in the hybrid cooling mode are described in detail below.

[0125] like Figure 5 As shown in , the control method of the evaporative cooling chiller includes the following steps:

[0126] Step 31: If the ambient dry-bulb temperature is between the first preset temperature and the second preset temperature, the hybrid cooling mode is started;

[0127] Among them, in step 31, the ambient dry bulb temperature T is detected by the temperature sensing package 12, the first preset temperature A1 can be set to 0°C, the second preset temperature A2 can be set to 15°C, or other temperature values ​​set by the user.

[0128] Step 32: in the mixed cooling mode, the first air valve 8, the second air valve 9 and the third air valve 10 are controlled to be closed;

[0129] In the hybrid cooling mode, the refrigerant is cooled by the evaporative cooling coil device, and the coolant is cooled by the surface cooler 2 at the same time. Through step 32, most of the air flowing in from the air inlet 4 directly passes through the first air duct 6, passes through the evaporative cooling coil device and the surface cooler 2 in sequence, and then flows out from the air outlet 5.

[0130] Step 33: Determine the range of the refrigerant inlet and outlet enthalpy difference. If it is in the first enthalpy difference range, keep the frequency of the fan 3 unchanged and execute step 36; if it is in the second enthalpy difference range, execute step 34; if it is in the third enthalpy difference range, execute step 35.

[0131] Step 34: adjust the frequency of the fan 3 according to the third preset method, and return to step 33.

[0132] Step 35: adjust the frequency of the fan 3 according to the fourth preset method, and return to step 33.

[0133] Among them, in steps 33 to 35, according to the enthalpy difference ΔH between the inlet and outlet of the refrigerant, it is judged whether the current heat exchange amount of the refrigerant meets the requirements. If it meets the requirements, the frequency of the fan 3 remains unchanged. If it does not meet the requirements, the frequency of the fan 3 is adjusted to adjust the heat exchange amount, so as to ensure the cooling demand of the refrigerant and avoid excessive frequency of the fan 3, achieving the purpose of energy conservation and consumption reduction.

[0134] Specifically, in step 33, the enthalpy difference ΔH between the inlet and outlet of the refrigerant is in the first enthalpy difference range: C1 ≤ ΔH ≤ C2; the enthalpy difference ΔH between the inlet and outlet of the refrigerant is in the second enthalpy difference range: ΔH < C1; the enthalpy difference ΔH between the inlet and outlet of the refrigerant is in the third enthalpy difference range: ΔH > C2. Among them, the values of C1 and C2 can be set by the user according to actual needs. For example, C1 can be set to 140 (kJ / kg) and C2 can be set to 175 (kJ / kg).

[0135] Specifically, in step 34, adjusting the frequency of the fan 3 according to the third preset method is specifically: making the adjusted frequency M" of the fan 3 in the mixed refrigeration mode satisfy the following defining formula:

[0136] M" = M" O + z3|ΔH - C1|.

[0137] In step 35, adjusting the frequency of the fan 3 according to the fourth preset method is specifically: making the adjusted frequency M" of the fan 3 in the mixed refrigeration mode satisfy the following defining formula:

[0138] M" = M" O - z3|C2 - ΔH|.

[0139] In the formula, M" O is the initial frequency of the fan 3 in the mixed refrigeration mode, generally 45 (Hz); z3 is a correction factor, dimensionless unit, generally taking an empirical value, for example, taking 1.4.

[0140] In other words, when the enthalpy difference between the inlet and outlet of the refrigerant is in the first enthalpy difference range, the frequency of the fan 3 is in a suitable range, which can not only ensure the heat exchange requirements of the refrigerant but also avoid energy waste; when the enthalpy difference between the inlet and outlet of the refrigerant is small (in the second enthalpy difference range), the frequency of the fan 3 can be increased to meet the heat exchange requirements of the secondary refrigerant; when the temperature difference between the inlet and outlet of the secondary refrigerant is large (in the third enthalpy difference range), the frequency of the fan 3 can be reduced to achieve energy conservation and consumption reduction.

[0141] Step 36: Judge the range where the temperature difference between the inlet and outlet of the secondary refrigerant is located. If it is in the first temperature difference range, keep the frequency of the fan 3 unchanged; if it is in the second temperature difference range, execute step 37; if it is in the third temperature difference range, execute step 38;

[0142] Step 37: Fully open the first air valve 8, increase the opening degree of the second air valve 9 in accordance with the fifth preset manner, and then return to execute Step 33;

[0143] Step 38: Fully open the second air valve 9, increase the opening degree of the third air valve 10 in accordance with the sixth preset manner, and then return to execute Step 33.

[0144] After the first adjustment of the frequency of the fan 3 according to the enthalpy difference between the inlet and outlet of the refrigerant through Steps 33 to 35, through Steps 36 to 38, the opening degrees of the respective air valves are adjusted to an appropriate range according to the temperature difference between the inlet and outlet of the secondary refrigerant, so that a part (most) of the air flowing in from the air inlet 4 directly passes through the second air duct 7 and enters below the surface cooler 2, thereby bypassing the evaporative cooling disc device by this part of the air and reducing the air resistance. When the opening degrees of the respective air valves are adjusted to an appropriate range, the second adjustment of the frequency of the fan 3 is performed again according to the enthalpy difference between the inlet and outlet of the refrigerant.

[0145] Specifically, in Step 36, the temperature difference ΔT1 between the inlet and outlet of the secondary refrigerant is in the first temperature difference range: B1 ≤ ΔT1 ≤ B2; the temperature difference ΔT1 between the inlet and outlet of the secondary refrigerant is in the second temperature difference range: ΔT1 < B1; the temperature difference ΔT1 between the inlet and outlet of the secondary refrigerant is in the third temperature difference range: ΔT1 > B2. Among them, the values of B1 and B2 can be set by the user according to actual needs. For example, B1 can be set to 3.5 (°C) and B2 can be set to 7 (°C).

[0146] Among them, when ΔT1 < B1, by fully opening the first air valve 8 and increasing the opening degree of the second air valve 9, more air directly passes through the surface cooler 2 to take away more heat on the surface cooler 2, so that the heat exchange amount of the secondary refrigerant increases, so as to adjust the temperature difference ΔT1 between the inlet and outlet of the secondary refrigerant to the first temperature difference range. On the contrary, when ΔT1 > B2, fully open the second air valve 9 and increase the opening degree of the third air valve 10, so that a part of the air bypasses the surface cooler 2 and flows out directly to reduce the heat exchange amount of the surface cooler 2, so that the heat exchange amount of the secondary refrigerant decreases, so as to adjust the temperature difference ΔT1 between the inlet and outlet of the secondary refrigerant to the first temperature difference range.

[0147] Specifically, in Step 37, increasing the opening degree of the second air valve 9 in accordance with the fifth preset manner is specifically: making the opening degree N of the second air valve 9 in the mixed refrigeration mode satisfy the following defining formula:

[0148] N = N O + z4|ΔT1 - C1|.

[0149] In Step 38, increasing the opening degree of the third air valve 10 in accordance with the sixth preset manner is specifically: making the opening degree N' of the third air valve 10 in the mixed refrigeration mode satisfy the following defining formula:

[0150] N' = N' O + z4|C2 - ΔT1|.

[0151] Where N O N' is the initial opening of the second air valve 9 in the mixed cooling mode, which is generally 10; O is the initial opening of the third air valve 10 in the mixed cooling mode, which is generally 10; z4 is a correction factor, a dimensionless unit, which is generally an empirical value, such as 1.4.

[0152] It should be noted that the maximum opening degrees of the second air valve 9 and the third air valve 10 are expressed as 100.

[0153] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the terms "first", "second", "third" and "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third" and "fourth" may explicitly or implicitly include one or more of the features.

[0154] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An evaporative cooling chiller, characterized in that: include: The unit housing, the surface cooler, the evaporative cooling coil device and the fan, the opposite sides of the unit housing are respectively provided with an air inlet and an air outlet, and the fan is arranged at the air outlet. The unit housing is provided with a first air duct and a second air duct separated from each other, the two ends of the first air duct are respectively connected to the air inlet and the air outlet, the surface cooler and the cooling coil device are arranged in the first air duct and are located in sequence between the air outlet and the air inlet, The air inlet end of the second air duct is connected to the air inlet in an open-closeable manner through a first air valve. The air outlet end of the second air duct is connected to the part of the first air duct located between the surface cooler and the evaporative cooling coil device in an openable and closeable manner through a second air valve. The air outlet end of the second air duct is connected to the part of the first air duct located between the fan and the surface cooler in an openable and closable manner through a third air valve; The refrigeration mode of the evaporative cooling chiller includes a natural refrigeration mode for cooling the secondary coolant through the surface cooler and a mechanical refrigeration mode for cooling the refrigerant through the evaporative cooling coil device; The evaporative cooling chiller also includes a controller, which is connected to the first air valve, the second air valve and the third air valve respectively to control the states of the first air valve, the second air valve and the third air valve. Wherein, the controller controls the first air valve and the air valve to be fully opened, and the third air valve to be closed, so as to start the natural cooling mode; The controller controls the first air valve to be closed, and the second air valve and the third air valve to be fully opened, so as to start the mechanical refrigeration mode.

2. The evaporative cooling chiller according to claim 1, characterized in that: The first air duct is arranged at the center of the unit housing and extends in the vertical direction, and the second air duct is arranged around the first air duct and extends in the vertical direction.

3. An evaporative cooling chiller according to claim 1 or 2, characterized in that: The controller is connected to the fan to control the frequency of the fan.

4. An evaporative cooling chiller according to claim 1 or 2, characterized in that: A temperature sensing package for measuring the ambient dry-bulb temperature is arranged on the outer wall of the unit housing.

5. An evaporative cooling chiller according to claim 1 or 2, characterized in that: The evaporative cooling coil device comprises: a water tank, a spray assembly, a heat exchange tube group and a filler. The spray assembly, the heat exchange tube group and the filler are arranged in sequence from top to bottom in the first air duct, the water tank is arranged below the filler, and the water tank is connected to the spray assembly through a water supply pipeline.

6. The evaporative cooling chiller according to claim 5, characterized in that: A first temperature sensor is provided at the inlet end of the heat exchange tube group, and the first temperature sensor is used to measure the inlet temperature of the refrigerant passing into the heat exchange tube group; A second temperature sensor is provided at the outlet end of the heat exchange tube group, and the second temperature sensor is used to measure the outlet temperature of the refrigerant passing into the heat exchange tube group.

7. The evaporative cooling chiller according to claim 5, characterized in that: A water pump, a ball valve and a one-way valve are arranged in sequence on the water supply pipeline.

8. An evaporative cooling chiller according to claim 1 or 2, characterized in that: A third temperature sensor is provided at the inlet of the surface cooler, and the third temperature sensor is used to measure the inlet temperature of the coolant passing into the surface cooler; A fourth temperature sensor is provided at the outlet of the surface cooler, and the fourth temperature sensor is used to measure the outlet temperature of the coolant passing into the surface cooler.

9. A control method for an evaporative cooling chiller, used to control the evaporative cooling chiller according to any one of claims 1 to 8, characterized in that: include: Start the corresponding cooling mode according to the range of ambient dry-bulb temperature; as well as Adjust the states of the first air valve, the second air valve and the third air valve according to the corresponding cooling mode to control the flow path of air from the air inlet to the air outlet, thereby achieving the purpose of reducing wind resistance; The refrigeration modes include natural refrigeration mode, mechanical refrigeration mode and mixed refrigeration mode. In the natural cooling mode, the refrigerant is cooled by the surface cooler; In mechanical cooling mode, the refrigerant is cooled by an evaporative cooling coil unit; In hybrid cooling mode, the secondary coolant is cooled by the surface cooler and the refrigerant is cooled by the evaporative cooling coil unit at the same time.

10. The control method according to claim 9, characterized in that: The following steps are involved: Step 11: If the ambient dry-bulb temperature is less than or equal to the first preset temperature, the natural cooling mode is started; Step 12: In the natural cooling mode, the first air valve and the second air valve are controlled to be fully opened, and the third air valve is closed; Step 13: Determine the range of the inlet and outlet temperature difference of the coolant. If it is within the first temperature difference range, keep the frequency of the fan unchanged; if it is within the second temperature difference range, execute step 14; if it is within the third temperature difference range, execute step 15; Step 14: adjusting the frequency of the fan according to the first preset method, and then returning to step 13; Step 15: Adjust the frequency of the fan according to the second preset method, and then return to step 13.

11. The control method according to claim 9 or 10, characterized in that: The following steps are involved: Step 21: If the ambient dry-bulb temperature is greater than or equal to the second preset temperature, start the mechanical cooling mode; Step 22: In the mechanical cooling mode, the first air valve is controlled to be closed, and the second air valve and the third air valve are controlled to be fully opened; Step 23: Determine the range of the inlet and outlet enthalpy difference of the refrigerant. If it is within the first enthalpy difference range, keep the frequency of the fan unchanged. If it is in the second enthalpy difference range, execute step 24; if it is in the third enthalpy difference range, execute step 25; Step 24: adjusting the frequency of the fan according to the third preset method, and then returning to step 23; Step 25: Adjust the frequency of the fan according to the fourth preset method, and then return to step 23.

12. The control method according to claim 9 or 10, characterized in that: The following steps are involved: Step 31: If the ambient dry-bulb temperature is between the first preset temperature and the second preset temperature, the hybrid cooling mode is started; Step 32: Control the first air valve, the second air valve and the third air valve to close in the mixed cooling mode; Step 33: Determine the range of the refrigerant inlet and outlet enthalpy difference. If it is in the first enthalpy difference range, keep the fan frequency unchanged and execute step 36; if it is in the second enthalpy difference range, execute step 34; if it is in the third enthalpy difference range, execute step 35; Step 34: adjusting the frequency of the fan according to the third preset method, and returning to step 33; Step 35: adjusting the frequency of the fan according to the fourth preset method, and returning to step 33; Step 36: Determine the range of the inlet and outlet temperature difference of the coolant. If it is in the first temperature difference range, keep the frequency of the fan unchanged; if it is in the second temperature difference range, execute step 37; if it is in the third temperature difference range, execute step 38; Step 37: fully open the first air valve, and increase the opening of the second air valve according to the fifth preset method, and then return to step 33; Step 38: Fully open the second air valve, and increase the opening of the third air valve according to the sixth preset method, and then return to step 33.

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