An intelligent dynamic defrosting method

Abstract

The present invention relates to the field of dehumidifiers. The purpose is to provide an intelligent dynamic defrosting method, which should have the characteristics of low investment cost and good defrosting effect while ensuring dehumidification performance. The technical solution is an intelligent dynamic defrosting method, which includes the following steps: 1) setting dehumidifier operating parameters and starting the dehumidifier; 2) the dehumidifier detects the ambient temperature t and the ambient relative humidity φ; 3) the dehumidifier determines the defrosting trigger temperature t C And calculate the defrost trigger time T C And the detection cycle T`; 4) defrost detection.

Description

Technical Field

[0001] The invention relates to the field of dehumidifiers, and in particular to an intelligent dynamic defrosting method. Background Art

[0002] At present, the judgment conditions for entering defrost in the dehumidifier industry are fixed: the defrost function is activated after the coil or fin temperature reaches the sub-zero temperature point and lasts for a certain period of time. This judgment method is simple but not intelligent. It does not take into account different environmental conditions, such as different ambient temperatures and different ambient humidities, different air moisture content, different evaporator coil and fin temperatures, and thus different degrees of frost, so the triggering conditions for entering defrost should also be different.

[0003] The current single defrosting method sacrifices dehumidification performance. For example, when the ambient temperature is 18°C ​​and there is slight frost, there is no need to defrost or the defrosting duration is very short, and the refrigeration system can allocate more time for dehumidification. When the ambient temperature is 5°C, there is severe frost, and defrosting cannot be started until the frost is very thick.

[0004] The dehumidifier industry has a single judgment on the conditions for entering defrost, also because there is currently no algorithm for measuring different working conditions and different judgment condition parameters. If simulation experiments are used to determine the parameters, because the ambient temperature and ambient relative humidity are dynamically changing, and there are many types of combinations of the two, so relying on experimental tests to accumulate data will bring a very large workload, and the human and material resources invested are also huge. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology and to provide an intelligent dynamic defrosting method, which should have the characteristics of low investment cost and good defrosting effect while ensuring the dehumidification performance.

[0006] The technical solution of the present invention is:

[0007] An intelligent dynamic defrosting method comprises the following steps:

[0008] 1) Set the dehumidifier operating parameters and start the dehumidifier;

[0009] 2) The dehumidifier detects the ambient temperature t and the ambient relative humidity φ;

[0010] 3) Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C With the detection period T`:

[0011] t C =-1℃, T C =α*lgN / (t1-β*lgN)+T, T`=40+α*lgN;

[0012] Among them, N = t*φ, α and β are coefficients, t1 and T1 are constants, and t1, β, and lgN are accurate to one decimal place;

[0013] or,

[0014] Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C :

[0015] t C =-1℃, T C =γ*lgW / (t2-δ*lgW)+T2, T`=40+γ*lgW;

[0016] Where, W = 621.97*P W / (101325-P W ), P W =φ*P WS / 100,P WS =610.78*e 17.269*t / (t+237.3) , γ, δ are coefficients, t2, T2 are constants, t2, δ, lgW are accurate to one decimal place;

[0017] 4) At the beginning of the detection cycle T', the dehumidifier operates in the dehumidification mode and performs defrost detection; when the detection cycle T' ends, return to step 2); At the beginning of the detection cycle T', the dehumidifier operates in the dehumidification mode and performs defrost detection; when the triggering condition of the defrost detection is met, the dehumidifier enters the defrost mode, and when the exit condition of the defrost detection is met, return to step 2);

[0018] The defrost detection is the real-time detection of the evaporator temperature t by the dehumidifier Z And record in real time Z ≤t C The duration T z .

[0019] In the step 1), the dehumidifier operation parameters include temperature, humidity and working time.

[0020] In step 4), the triggering condition for defrost detection is T Z ≥T C .

[0021] In step 4), the exit condition of defrost detection is t Z ≥3℃ and maintain for more than 3 minutes.

[0022] In step 4), the evaporator temperature t Z is the evaporator coil temperature or the evaporator fin temperature.

[0023] In the step 3), 10≤α≤30, 1≤β≤2, and α is an integer.

[0024] In the step 3), 1.5≤t1≤3.0, 5≤T1≤15, and T1 is an integer.

[0025] In the step 3), 10≤γ≤30, 1≤δ≤2, and γ is an integer.

[0026] In the step 3), 1.4≤t2≤2.8, 5≤T2≤15, and T2 is an integer.

[0027] The beneficial effects of the present invention are:

[0028] The present invention only needs to detect the ambient temperature and the ambient relative humidity to dynamically calculate the judgment conditions for entering defrosting in real time, match different defrosting trigger conditions and detection cycles according to different environmental conditions, and select different frosting durations to optimize the defrosting effect of the dehumidifier, thereby realizing intelligent dynamic defrosting. In addition, the present invention only needs to adopt the existing temperature and humidity sensors of the dehumidifier, without increasing the investment in hardware resources and the production cost. Therefore, the present invention has important reference significance for the innovation of defrosting technology in the dehumidifier industry, and even in all refrigeration-related industries such as air conditioners and refrigerators. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the working steps of the present invention.

[0030] Figure 2 It is lgN-T C Graph.

[0031] Figure 3 It is lgW-T C Graph.

[0032] Figure 4 It is lgN-T C / lgW-T C . DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0034] Example 1

[0035] An intelligent dynamic defrosting method comprises the following steps:

[0036] 1) Set the dehumidifier operating parameters, including temperature, humidity, working hours, and start the dehumidifier;

[0037] 2) The dehumidifier detects the ambient temperature t and the ambient relative humidity φ;

[0038] 3) Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C With the detection period T`:

[0039] t C Determined to be -1°C;

[0040] First calculate the real number N, N = t*φ; then calculate the logarithm of the real number N with a base of 10, lgN, N = t*φ; finally calculate T C , T C =α*lgN / (t1-β*lgN)+T1;

[0041] Calculate the detection period T`, T`=40+α*lgN;

[0042] Among them, α and β are coefficients, and t1 and T1 are constants. According to empirical calculation, the value ranges of α, β, t1, and T1 are as follows:

[0043] 10≤α≤30, α is an integer, 1.5≤t1≤3.0, 1≤β≤2, 5≤T1≤15, T1 is an integer, t1, β, lgN are accurate to one decimal place;

[0044] 4) Defrosting detection

[0045] At the beginning of the detection cycle T`, the dehumidifier operates in the dehumidification mode and performs defrost detection at the same time;

[0046] When the detection cycle T' ends, return to step 2); when the trigger condition of defrost detection is met, the dehumidifier enters the defrost mode (dehumidification pause), and when the exit condition of defrost detection is met, return to step 2);

[0047] The defrost detection is the real-time detection of the evaporator temperature t by the dehumidifier Z (t Z is the evaporator coil temperature or the evaporator fin temperature) and records it in real time Z ≤t C The duration T z , the trigger condition of defrost detection is T Z ≥T C , the exit condition of defrost detection is t Z ≥3℃ and maintain for more than 3 minutes.

[0048] In this embodiment, t C =-1℃, and the defrost trigger time T is obtained according to different situations C for:

[0049] Assume α = 20, t1 = 1.5, β = 1.0, T1 = 5, then TC =α*lgN / (t1-β*lgN)+T1

[0050] =20*lgN / (1.5-lgN)+5; get the following table:

[0051]

[0052]

[0053] lgN and T C The relationship is as Figure 2 As shown in the figure, T C It increases with the increase of lgN. lgN is related to the ambient temperature t and the ambient relative humidity φ. The larger the product of t and φ, the larger the lgN.

[0054] Under normal circumstances, when the ambient temperature is above 18°C, the coil or fin temperature will not reach -1°C, so it will not trigger the defrosting state;

[0055] The specific working steps of this embodiment are as follows:

[0056] Assume α=20, t1=1.5, β=1, T1=5, t C =-1℃;

[0057] The dehumidifier starts and enters the dehumidification mode. The first detection cycle begins: initial ambient temperature t = 10 °C, initial ambient relative humidity φ = 60%, defrost trigger temperature t C =-1℃, defrost trigger time T C =28min, the detection period T' is 56min;

[0058] During the 5th to 33rd minute of the first detection cycle (during this period the dehumidifier remains in dehumidification mode), the evaporator temperature t Z The temperature is always below -1℃, so the dehumidifier enters the defrost mode (dehumidification mode is paused) at the 34th minute of the first detection cycle. After running in the defrost mode for 6 minutes, the defrost exit condition is met, the first detection cycle ends, and the dehumidifier exits the defrost mode.

[0059] At the beginning of the second detection cycle, the dehumidifier re-enters the dehumidification mode. During the dehumidification process, the air is heated by the condenser and the compressor also generates heat, which causes the actual ambient temperature to rise and the humidity to drop. Therefore, the ambient temperature t=11℃, the ambient relative humidity φ=50%, and the defrost trigger temperature t C =-1℃, defrost trigger time T C =23min, the detection period T' is 54 minutes;

[0060] During the 5th to 28th minute of the second detection cycle (during this period the dehumidifier remains in dehumidification mode), the evaporator temperature t Z The temperature is always below -1℃, so the dehumidifier enters the defrost mode (dehumidification mode is paused) at the 29th minute of the first detection cycle. After running in the defrost mode for 5 minutes, the defrost exit condition is met, the first detection cycle ends, and the dehumidifier exits the defrost mode.

[0061] The subsequent steps are similar to the above detection cycle and are therefore omitted.

[0062] Example 2

[0063] An intelligent dynamic defrosting method comprises the following steps:

[0064] 1) Set the dehumidifier operating parameters, including temperature, humidity, working hours, and start the dehumidifier;

[0065] 2) The dehumidifier detects the ambient temperature t and the ambient relative humidity φ;

[0066] 3) Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C With the detection period T`:

[0067] t C Determined to be -1°C;

[0068] First calculate the saturated water vapor partial pressure P WS , P WS =610.78*e 17.269*t / (t+237.3) ; Then calculate the water vapor partial pressure P W , P W =φ*P WS / 100; then calculate the air humidity W, W = 621.97*P W / (101325-P W ); finally calculate T C , T C =γ*lgW / (t2-δ*lgW)+T2;

[0069] Calculate the detection period T`, T`=40+γ*lgW;

[0070] Among them, γ and δ are coefficients, and t2 and T2 are constants. According to empirical calculations, the value ranges of γ, δ, t2, and T2 are as follows:

[0071] 10≤γ≤30, γ is an integer; 1.4≤t2≤2.8, 1≤δ≤2, 5≤T2≤15, T2 is an integer, t2, δ, lgW are accurate to one decimal place;

[0072] 4) Defrosting detection

[0073] At the beginning of the detection cycle T`, the dehumidifier operates in the dehumidification mode and performs defrost detection at the same time;

[0074] When the detection cycle T' ends, return to step 2); when the trigger condition of defrost detection is met, the dehumidifier enters the defrost mode (dehumidification pause), and when the exit condition of defrost detection is met, return to step 2);

[0075] The defrost detection is the real-time detection of the evaporator temperature t by the dehumidifier Z (t Z is the evaporator coil temperature or the evaporator fin temperature) and records it in real time Z ≤t C The duration T z , the trigger condition of defrost detection is T Z ≥T C , the exit condition of defrost detection is t Z ≥3℃ and maintain for more than 3 minutes.

[0076] In this embodiment, the defrost triggering temperature t is obtained according to different conditions. C And defrost trigger time T C for:

[0077] Assume γ = 20, t2 = 1.4, t C =-1℃; assuming δ = 1.0, T2 = 5, then T C =20*lgW / (1.4-lgW)+5;

[0078] The following table is obtained:

[0079]

[0080] lgW and T C The relationship is as Figure 3 As shown in the figure, T C It increases with the increase of lgW. lgW is related to the ambient temperature t and the ambient relative humidity φ. The larger the product of t and φ, the larger lgW is.

[0081] Under normal circumstances, when the ambient temperature is above 18°C, the coil or fin temperature will not reach -1°C, so it will not trigger the defrosting state;

[0082] The specific working steps of this embodiment are as follows:

[0083] Assume γ = 20, t2 = 1.4; Assume δ = 1, T2 = 5, t C =-1℃;

[0084] The dehumidifier starts and enters the dehumidification mode. The first detection cycle begins: initial ambient temperature t = 10 °C, initial ambient relative humidity φ = 60%, defrost trigger temperature t C =-1℃, defrost trigger time T C =25min, the detection period T' is 54min;

[0085] In the 5th to 30th minute of the first detection cycle (during this period the dehumidifier remains in dehumidification mode), the evaporator temperature t Z The temperature is always below -1°C, so the dehumidifier enters the defrost mode (dehumidification mode is paused) at the 31st minute of the first detection cycle. After running in the defrost mode for 6 minutes, the defrost exit condition is met and the first detection cycle ends.

[0086] At the beginning of the second detection cycle, the dehumidifier re-enters the dehumidification mode. During the dehumidification process, the air is heated by the condenser and the compressor also generates heat, which causes the actual ambient temperature to rise and the humidity to drop. Therefore, the ambient temperature t=11℃, the ambient relative humidity φ=50%, and the defrost trigger temperature t C =-1℃, defrost trigger time T C =20min, the detection period T' is 52 minutes;

[0087] During the 5th to 25th minute of the second detection cycle (during this period the dehumidifier remains in dehumidification mode), the evaporator temperature t Z The temperature is always below -1℃, so the dehumidifier enters the defrost mode (dehumidification mode is paused) at the 26th minute of the first detection cycle. After running in the defrost mode for 5 minutes, the defrost exit condition is met, the first detection cycle ends, and the dehumidifier exits the defrost mode.

[0088] The subsequent steps are similar to the above detection cycle and are therefore omitted.

[0089] Depend on Figure 4 It can be seen that lgN-T C Curve and lgW-T C The trajectory of the curve is basically similar, and lgW-T C The curve is located at lgN-T C Above the curve, it shows that the results obtained by the two calculation methods, lgN (N = ambient temperature t * ambient relative humidity φ) and lgW (W is the air humidity content), are very close. The accuracy of the lgN calculation method is not as high as that of the lgW, but the calculation process is simple, while the calculation process of the humidity content W is complicated. Therefore, the lgN calculation method can be used as a fast and simplified calculation method to replace the lgW calculation method when the accuracy requirements are not so high.

[0090] When the ambient temperature is high (above 18°C), the present invention can prevent the dehumidifier from defrosting or shorten the defrosting time, thereby ensuring that the cold system can allocate more time for dehumidification; when the ambient temperature is low (serious frost is prone to occur at this time), the present invention can enable the dehumidifier to defrost in advance to avoid the occurrence of thick frost that affects the defrosting effect, thereby reducing the subsequent dehumidification performance.

[0091] Example 1: Defrosting in advance when the temperature is below 5°C (T C Less than 15 minutes), Example 2 defrosts in advance when it is slightly below 4°C (T C In the conventional method, no matter the ambient temperature is high or low, it needs to be kept below -1°C for 15 minutes before defrosting.

[0092] Experimental verification

[0093] If the defrost trigger temperature and defrost trigger time are used for testing, when the initial working condition is 10℃ / 60%, the dehumidification time of the first test cycle is 5+15=20 minutes, and the defrost time is 5 minutes, totaling 25 minutes. The working condition of the second test cycle changes to 11℃ / 50%, the dehumidification time is 5+15=20 minutes, and the defrost time is 5 minutes, totaling 25 minutes. The dehumidification operation time in the two cycles is 40 minutes, accounting for 40 / 50=80.0% of the entire two cycles.

[0094] The intelligent dynamic defrost calculation method (Example 1) was used for testing. When the initial working condition was 10°C / 60%, the dehumidification time in the first detection cycle was 5+28=33 minutes, and the defrost time was 6 minutes, totaling 39 minutes. In the second detection cycle, the dehumidification time was 5+23=28 minutes, and the defrost time was 5 minutes, totaling 33 minutes. The dehumidification operation time in the two cycles was 61 minutes, accounting for 61 / 72=84.7% in the two cycles.

[0095] Because dehumidification is prone to frost under low-temperature conditions, resulting in a decrease in dehumidification performance, it is difficult to improve the dehumidification performance under low-temperature conditions. After adopting the intelligent dynamic defrosting method, compared with the two cycles, the proportion of dehumidification working time increased from 80.0% to 84.7%, the effective dehumidification time increased by 4.7%, and the corresponding dehumidification performance increased by 4.7%.

[0096] If tested under 24-hour 10℃ / 60% constant temperature and humidity laboratory conditions, the dehumidification time using the conventional method is 1155 minutes in total, and the dehumidification time using the intelligent dynamic defrost calculation method (Example 1) is 1221 minutes in total. The dehumidification working time ratio is increased from 80.2% to 84.8%, the effective dehumidification time is increased by 4.6%, and the corresponding dehumidification performance is improved by 4.6%.

[0097] In the present invention, the dehumidifier is provided with an environment temperature sensor, an environment relative humidity sensor, and an evaporator coil temperature sensor (or an evaporator fin temperature sensor).

[0098] The ambient temperature sensor detects the air temperature at the air inlet (obtains the ambient temperature t), the ambient relative humidity sensor detects the relative humidity of the air at the air inlet (obtains the ambient relative humidity φ), and the evaporator coil temperature sensor detects the minimum temperature of the evaporator coil (obtains the evaporator temperature t z ), the evaporator fin temperature sensor detects the minimum temperature of the evaporator fin (to obtain the evaporator temperature t z );

[0099] The ambient temperature sensor and ambient relative humidity sensor are arranged at the air inlet of the dehumidifier, the evaporator coil temperature sensor is arranged at the lowest temperature point of the evaporator copper tube, and the evaporator fin temperature sensor is arranged at the lowest temperature point of the evaporator fin. All these sensors are electrically connected to the control board of the dehumidifier and send the detected signals to the sampling circuit of the control board.

Claims

1. An intelligent dynamic defrosting method, comprising the following steps: 1) Set the dehumidifier operating parameters and start the dehumidifier; 2) The dehumidifier detects the ambient temperature t and the ambient relative humidity φ; 3) Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C With the detection period T`: t C =-1℃,T C =α*lgN / (t1-β*lgN)+T1,T`=40+α*lgN; Among them, N = t*φ, α and β are coefficients, t1 and T1 are constants, and t1, β, and lgN are accurate to one decimal place; or, Dehumidifier determines defrost trigger temperature t C And calculate the defrost trigger time T C With the detection period T`: t C =-1℃,T C =γ*lgW / (t2-δ*lgW)+T2,T`=40+γ*lgW; Where W = 621.97*P W / (101325-P W ), P W =φ*P WS / 100,P WS =610.78*e 17.269*t / (t+237.3) , γ, δ are coefficients, t2, T2 are constants, t2, δ, lgW are accurate to one decimal place; 4) At the beginning of the detection cycle T', the dehumidifier operates in the dehumidification mode and performs defrost detection at the same time; when the detection cycle T' ends, return to step 2); when the trigger condition of the defrost detection is met, the dehumidifier enters the defrost mode, and when the exit condition of the defrost detection is met, return to step 2); The defrost detection is the real-time detection of the evaporator temperature t by the dehumidifier Z And record in real time Z ≤t C The duration T z ; In step 4), the triggering condition for defrost detection is T Z ≥T C ; In step 4), the exit condition of defrost detection is t Z ≥3℃ and maintain for more than 3 minutes.

2. The intelligent dynamic defrosting method according to claim 1, characterized in that: In the step 1), the dehumidifier operation parameters include temperature, humidity and working time.

3. The intelligent dynamic defrosting method according to claim 2, characterized in that: In step 4), the evaporator temperature t Z is the evaporator coil temperature or the evaporator fin temperature.

4. The intelligent dynamic defrosting method according to claim 3, characterized in that: In the step 3), 10≤α≤30, 1≤β≤2, and α is an integer.

5. The intelligent dynamic defrosting method according to claim 4, characterized in that: In the step 3), 1.5≤t1≤3.0, 5≤T1≤15, and T1 is an integer.

6. The intelligent dynamic defrosting method according to claim 5, characterized in that: In the step 3), 10≤γ≤30, 1≤δ≤2, and γ is an integer.

7. The intelligent dynamic defrosting method according to claim 6, characterized in that: In the step 3), 1.4≤t2≤2.8, 5≤T2≤15, and T2 is an integer.

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